CROSS REFERENCE TO RELATED APPLICATIO

pHMJ!J This application claims priority to IIS. Pate Application No, 15/389,326, filed fSecember 2% 20.16 and t.o _: VS. Pravisiouai Application No. 62 385,854 filed oil September ¾ 20.16, both of which are herein mcotporaled by reference, in their entirely.

BACKGROU D

il03 An u roa t d vehicle, w ich raay also be referred to as m autonomous vehkle. is a vehicle capable of travel, without, a physiea!ly-preserit kr naii. operator. .An unmanned ehicle may operate hi a femofe-coBirol mode, in ¾a a«to«oi»0KS mode, or ia a partially autoiiQmotis mode.

|0$03J When an unaiaraied vehicle operates in a remote-control mode _* a pilot or driver that is at a remote location c n control the unmanned vehicle ia commands that are s rai to the unmanned vehicle via a wireless link. When die unmanned vehicle operates m autonomous mode, the aaa¾aancd vehicle typically moves based OK p eprog ammed navigation aypoints, dynamic' automation- systems, or a combination of these Further, seme unmanned vehiete cart operate -in both a remote-control mode and: -an autonomous mode, and in some instances ma d so sinndtaneously. For hisiatjee, a remote pilot or driver may wish to leave navigation to an uOTomous system while manually perfofrnisg another task, s«e as Operating a mechanical system or picking up objects, as an example.

00O4| Vario us types of unmanned vehicles exist f various diifeent envimnnienis.

For nisianee, uBtnaaned vehicles exist fat operation in ike air, on the ground, mider aier.. and m space. Examples Include quad-copters and tail-sitter U ^' AVs _* among others. U mnHcd vehicles also exist for hybrid operations which mirlti-enviroririieiit operation is ^: possible,. Examples of hybrid linmanned vehicles ciude an amphibioas craft tot is capable of operatkm on land as w ll as on water or a floatplane that is capable of landing on water as well, as on land. Othe examples are also possible. SUMMARY

{009SJ Example impieme atioas may relate to various technkpes for picking up, ftao.spQi ti¾, and lowering a pay load coupled to a tether of a winc system arranged oft m unmanned aerial vehicle {IJAV}, For example., the winch system may metede a motor for winding and. tmwhid g the tether ftom a spoof, and the UAY's control system may operate the motor to lower tlie tether .toward the ground so a payload may be attache^ to the tether. The control system: may further monitor an.4-aaal.yze an: electric current supplied, to the moto in order to dete mine whether the payload has heen attached to the tether. ¾ another example, the cont ol system, may monitor and analyze the motor enfreut in order to determine, when lowering a payioad, that the payload has reached the ground and respo siveiy operate the motor to detach, the: payload -from the tether. The control system may then further mo itor and analyze the motor current to deiermme whether the payload has detached from the tether.

{Θ0Θ6| In one aspect, a system is provided he system includes a tether disposed oft « spool and a. motor arranged in UAV, where operating the motor la -a- firs mode aud second; tuode respectively counters anrl assists unwindi g of tlie tether due to gravity. Tlie syste _; ro feriher includes a payload coupling apparatus- stxne&asd to mechanically couple the tether to th payload and a pay!oad latch switohable between a closed position that prevents the payload from being lowered from the OAV and an open position that allows the pay load to be lowered from the U V. Additionally, the system includes a control system configured to determine that the UA.V is located at a piefcup location and responsiveiy operate in a. payload pickup mode. Pining operation m the payioad pickup mode, the control system is configured to open the payload latch, and operate the motor to unwind a predetermined length of the tetter corresponding to a payload aitechftient altitude for the payload coupling apparatus. After unwinding the predetermined length of the tether and -wafting for a predetermined payload attachment period, the control s stem is further configured to perate the motor in the first tH de f r a predetermined attachment verificatio period and deterrninc, based at least i part on. motor current during the predetermined aftae ^' hmeai verification period, tha the payload couplin apparatus is mechanically coupled, to the payload. The control system is further configured to, responsive to the detenninatiou that the payload coupling apparatus Is mechatheall coupled t the payload, operate the motor to retract the tether and, while retracting the tether, determine that both; (a) an unwound length of the tether ½ less ma a mreshold length and ih) the motor eurrent is greater than, a threshold euxrent, and responsively operate the motor to pull the payload into receptacle on a lower .surfkse. of the UAV. Additionally, the eoritrol .system is ¾s»fi ti¾d to, after operaiioa of the motor to pitE the pay toad info the receptacle, close the pay load latch to secure the payioad in the receptacle,

}¾¾07] in another aspect, another system is provided. The sysicm includes a tethe disposed en a spoof and a motor arranged m a UAV, where operating ^" die motor hi a first mode an a second mode respectively counters and assists unwinding of the tether due to: gravity.. The system further iriemde a payioad coupling apparatus stRretured. to mechanically couple the tether to the pay load. au a control system configured, to -deie mne that- the TJAV ^" is locate at a target location and respoasively operate in. a delivery mode, During operation i the delivery Μοφέ, the: control system is configured to operate the motor to ya ind the tether according to a predetermined descent profile, determine that an unwound lengt of tile tether is greater than, a ihreshofd length dial corresponds to a predetermined near-ground attitude of

■*r BRIEF DESC iPTfO OF THE DRA I GS

[0¾li Figure i A is a simplified iitesteadon. of an istananned aerial -vehide, according to art example effibodlniertt:

}0M2| Figure .IB is a simplified, illustratiori of an Biunanned aerial vehicle, accordin to as exam le embodiment..

|0013| Figure lC is a siniplified illustration of an muuanned. aerial vehicle, accordin to aa example -embod ment

|0<ϊί | Figure ID is a simplified illustrat : of an. unumnned aerial veSuele, according to an ex m le embodiment.,.

i ftlSi Figure I B is a simplified illasfrafiou of as lanna raed aerial vehicle, according t an exaBiple embodi ieBt

(00161 Figure 2 is a simplified block diagram. illnstratiBg eamporicats of an unmanned aerial vehicle,, accor ding to an example embodiment,

|0917} Figure 3 is a simplified block diagram illustratoig a IJAV system, according to 'm example embo imen

00 ί S I Figures 4A, 4 , and 4C show a payload delivery apparatus, aeeordtBg t exatnple em di ents.

j-0919 ^' j Figure 5A. shows a .perspective view of a payioad del vw apparatus 00 taeluding pay!oad 510, according to an example embodiBieai

|9020| Figure 5B is a cross-sectional Side v ew of payload deli ver apparatus 500 and payldad- 510 shewn in Fignre 5A..

|002l| Figure 5C is a side view of pay!oad. delivery apparatus 5#-a«d payload 510 shown in Figures 5 A and SB.

(00221 Figure o ^" A is a. perspective view of payload coupling apparatus 80Q, according to an example embodiment.

(0023 Figure 68 is a side view o payioad coupliug apparatus Ά .shown in Figure

6A.

the fuselage of a DAY, {Θ026 Figure 8 is mother pers ective vie of payload coupling apparatus 800 shown

In Figures 6 A-f , prior to insertion too a payload coupling app aratos receptacle positioned in the fiiseiage of a D AY

}M27 Figure 9 shows a perspective view of a recessed restraint slot and payload coopling apparatus receptacle positioned is a fuselage of a tJAV.

{002-8] Figure lOA shows a side view of a payload delivery apparatus 500 with a handle 511 of payioad 510 secured wuh.m a payload coupling apparatus 800 as th payload 510 moves ifew wdty prior to touching down for deli ery,

{0029] Figure -|0B shows a side view of payload delivery apparatus 500 after payload

510 has landed on the groiard showiiig payload eowplieg ajsparatus 800 deeoia led from handle 511 of payload 510.

(0O3O| Figure IOC shows a side view of pay ad delivery apparatus 500 with payload coupling appajatos 80 moving away from handle 51 ί of payioad 510.

|003J I Figure 1 1 is a side view of handle S i 1 of payload 510,

{0032] Figure .2 shows a pair of loefcin pins .570,.572 extending through holes 14 and 516 in handle 5 i | of payload SiO io secure the handle 51 1 and top of payload 510 within die fuselage of a DAY.

{0033] Figure 13 A is a perspective vi¾ of pay load eoupINg apparatus 90 prior to having a handle of a payload positioned within: slot 920 of payload coupling apparatus 900. 0034| Figure I3B is a perspective view of payload coupling; apparatas 900 alter ddivering: a payload and deeotjpiis fears a handle of a payload.

{0035] ^" Figure- A is a front perspective view of payload couplin apparatus 900 shown m Figures 13 A nd 138. according to an example embodiment

{0036] Figure !4B is a rear perspeetive view -of payioad coupling apparatus 90 shown, in Figure I4A.

fi03T| Figure I4€ is a side view of payload eoupli apparatus 900 shown i Figures

14A a«d !4B,

{0038] Figure 141 is a: front view of payioad eowpltsg apparatus 9 0 s¾ow» in

Figures: 14A44C,

{0039] Figure ! 4E is a to view of payioad couplin apparatus 900 shown in. Figures

14A:- .

{0040] Figure 15 A is a perspeetive view of payioad eotipiing apparatus 1006, aeeording to m e am e embodiment

|<M)6?J Figure 33 is a flow chart of a method for detecting nd addressing downward forecs on te!her when lowering a payload toward the ground;, according to an example embodiment

ΙΘ 681 Figure 36 is a flow chart of a method for detecting and addressing downward forces on a tether when winching, a payload toward a UA.V, according to an example embodimeiit,

j M½9J Figure 3? is a flow chart of a -.method for detecting whether a AV has successfully picked up a payload, according to an example embodiment

J0t)70| Figure. 38A illustrates a portion of a state diagram of a IJAV earn ing out a payload. pickup and delivery process, according to an example embodiment.

(007l| Figure 38B illustrates another portion of fee state diagram of a UAV carrying out a payload pickup and delivery process, according to an example .embodiment,

j f)721 Figure 3SC illustrates another portion of the state diagram of a FJAV carrying out a payload pickup: and -delivery process, according to s: example embodiment

j¾9? | The present embodiments are related to the use of -unmanned aerial -ve icles (UA s) or unmanned aerial systems (UASs) (referred to collectively herein as UAVs) that are used to earry a p yioad to be delivered or retrieved. As examples, U Vs may be used to deliver or retrieve a payioad to orfrom an in i idual or business. In operation the payioad t be delivered is secu ed; to the UAV and the UAV is then flo n to the desired deliver site. Qttee the UAV arrives at the delivery site, the ^: UAV may land to deliver the payioad, or operate io a hover rnode and lower the payioad frOai the UA towards the delivery site using a tether and a winch mechanism positioned will i the UAV, Upon touehdowa of die pa ioad, a payioad. coupling apparatus,, sometimes referred to as a "capsule," is automatically decoupled ^" h¾ra the payioad, I» addition, the payioad may be- retrieved while the UAV is operating in a hove mode by positioning a handle of the payioad into a slot in die payioad ■coupling apparatus.

|0975f ^' in order to deliver the payioad, the UAV ma include arious mechanisms to secure the payioad during transport and release the payioad upon delivery. Example eiiibodi eats may take the for of or otherwise relate to an apparatus for passi vely coupling a payioa to a O. fer transport and releasing the payioad upon, deiivery,

f {$76! Sach a pa ioad coupling apparatus .may include a housing coupled to the UA by a iether ihat .may be wound, aad: uawonnd to raise and lower the housing with respect to the UAV. The housing may include one or more swing arms adapted t extend from the bousing at an. acute angle, fomiing a book on which the payioad may be attached. When the .housing and attached, payioad are lowered from the UAV (e.g. _: , by unwinding the tether) to a transport location below the UAV (e.g., the grouad), the payioad nsay detach ftom the ttoofe. within a cavit in the fuselage when the casus of the &yl &d c ining apparatus are n •engagement w¾ i maitag eatas within the fuselage. However, where earns are used, the eatas Of the pay load coupling apparatus and the mating caois wliliiis a payload eoopiktg receptacle is the fuselage niay properly rotate the pay bad coupling apparatus to orient the payload hi a desired position with respect to the iiselage,

I ^' OOSli A significant advantage of the payload coupling apparatus is that the paytoad coupling apparatus includes no movin parts^ thereb reducing its complexit and reducing the possibility of part failure which exists when moving parts are .involved in a payloa coupling ap aratus,

J0 ⁽ i82| ihe payload may advantageously iaciude a haad¼ that is well-suite for positioning within the slot of {fee payload coupling apparatus. Tile andle may he constructed of a thin, flexible plastic material having -a high degree of itexikiiity allowhig for eas iosertiorJ into the slot of the pay load coupling mechanism, and also for easy decoupling from, the slot of the payload coupling taeehattism upon landing; of the payload, Handle flexibility is desirable to allow the payload arid payload coupling apparatus to hang vertically straight, as the handle bends to match the angle of the slot in the payload couplin apparatus, A rnote rigid handle makes it easier for the payload couplin apparatus to decouple front die handle upon package landing, although it the handle is too flexible the payload coupling apparatus eoukl flip ever and not release, Fi beruiote, it is desirable that upon decoupling, the handle should spring back to a vertical orieaiaiioa: which further rednces the re-hookiag of the handle with the. slot of the payload coupling apparatus, and to pull the package tight iato the restraint when engaging within the fuselage of die UA.V< It should also be noted that ihe handle eoukl also be out of paper or other natural fiber, with or without piastie lamination or piastic giass natural fibers for exits strength. As an example, fiber fein breed paper niay he used as well,

f M83 The handle ma also advantageously include a pair of holes that are adapted to receive locking pins positioaed within the OA¥, T¾e lockin pins may have a, conical shape to facilitate insertion int the holes in the handle and to pull the paekage int right: engagemerji: within the recessed restraint slot fit the fuselage of the UAV, Once the earns of the payload coupling apparatus are engaged with, the mating earns within the fuselage, the handle is positioaed in the desired orientation. A servo: m tor or other meehanisrn such as a regular electric motor with leadsciew, -or rack and pinion with limit switches to control travel ( r other mechanism: such, as a linear actuator) niay be used to niove the conical- locking pins through the holes is the handle to hold the handle and payload beneat tightly in position, allowin for high speed fligh t of the ti<W w i the payload is secured beneath the UAV. Alternatively, ike locking ^' pirn or pin could be mo ed into positloa within a recess or opening to die payload coupling apparatus itself, rather than toto holes to toe handle of the .of the package id secure the payload coupling apparat s and package to the UAV,

|IMM4| The pay toad may take the form of an aerodynamic tote, although the payload may have any tunaber of tofierent configuratloas sad geometries. However, where a linear recessed restraint slot is positioned with t&e feseiage, it is desirable that die top of the payload has a generally linear shape to it withia the linear recessed restrain slot within the fuselage; 0{|85| The pay load coupling .raeehaolsni may have different configurations as well.

For example, a tethe may be attached to a hoifora of the pay!oad: cot!piitig apparatus, and is ositioaed - within a vertically extending tether slot in the payload coupling apparatus. The vertical tether slot extends through: the payload coupling apparatus that is adapted to receive a handle of a payload. In this position, the handle of toe payload is positioned -within the slot dirisg deliveiy and reftievai The payload eo¾p ling apparatus also includes a pair of upwardly extending fingers positioned about the slot with an opening between the pair of lagers.

|.0$8$j When the payload touches the ground, toe payload coupling apparatus ^• continues - td m downwardly and automatically Is decoupled fi nn toe handle of toe payload. The payload conpi tog appafaius may ieetade a top half that is weighted, suc ihat upon decoupling fiorn the handle of the payload, toe payload coupling apparatus tips over and: rotates I SO degrees such that the pair of upwardly extending fingers are rotated IS!) an extend: downwardly. During this rotation, the tether becomes disengaged from the vertical tether stot and moves through the opening between the pair of fingers,. A a result, toe payload coupling is prevented from reengaging with the handle of the payload because toe slots extends downwardly, in addition, the downwardly extending slot after release of toe handle also helps to prevent the payload: coupling apparatus from engaging with powe lines or tree branches as it is winched back, to the U ^' AV, because toe opening: -in the slot extends downwardly. Alternately, the payload coupling apparatus ma be bottom weighted,

JQii87f This embodiment of the payload coupling apparatus may also include cams on an other surface thereof adapted to engage mating cams within a payload coupling apparatus receptacle within the fuselage to orient the payload coupling apparatus in a desired position within toe fuselage of the OA V.

#88 In nother emtjodinient, a. vertical slo may he positioned within the payload coupling apparatus adapted to receive a handle of a payload and to support the handle and payload during delivery a d retrieval. 1» this ombodimeai,- a tether slot is positioned on exterior & ilie pay load coupling apparatus, . and the top of the payload coupling apparatus is weighted such that when the payload reaches the ground, the pay load couplin apparatus continues to move downwardly until the haudle is decoupled from the slot of the payload coupling apparatus. Once decoupled, the weighted payload couplin ffieehauism rotates 90 degrees such that the slot cannot reengage with the handle of the payload during retrieval or eatch en power lines or tree branches.. This eraDodhneot of die payload coupling mechanism ma include earns eu an. outer surface thereof adapted to engage mating earns wifhin the feela e of l te tJAV to orient the payload CQUpli mechanism, and the handle and payload., m a desired position,

0089 lit addition, the payload delivery syste ats omatieaSly aligns die package during winch tip, orienting it for minhisnm dra along the aircraft's tong tdiual axis. This aiigtunent enables high speed forward flight, after pick: up. The alignment is accomplished- throttgh the shape of the payload hook and receptacle. The hook (also called capsiile due to its shape) has cam features around its perimeter which, always orieut it in a. defined direction when it engages into the cam featisres insid the receptacle of the fuselage of the OAV, The tips of the cam shapes on both sides of the capsule are asymmetric to prevent jamming the oil degree oneRtattoa. in this regard, helical cam surfaces may .meet at an apex on one side of the payload: coupling raec attism, and helical earn surfaces may meet at a rounded apes on the other side of the payload coupling mechanism. The hook is speeiieally designed so that the package lianas in the eenterltne of the hook, enabling alignment i« both directions from 90 degrees.

|0099J Besides the alignment fimetionaiity, the payload hook also releases the package passively and automatically when, the package touche the round upon delivery, "Ihis is accomplished through the shape and angle of the hook slot at d the corresponding handle on the package. The hook slides off die handle easi ly when the payload touche down due to the mass of the capsiile and also me inertia waiittag to continue moving the capsule downward, past the package. The end of the hook is designed to be recessed slightly from the body of the capsule, which, prevents the hook from accidentally . reattaching to the handle. After successful release, the hook gets winched hack up into the aircraft. All. this funcdeffiaiity (package alignment during pickup and passive release during delivery) may advantageously be achieved without any moving parts in this hook embodiment (inferred to as a, solid state design). This greatly increases reliability and: reduces cost. The simple design also makes user interaction very clear aud seii-explaaatory. la addition, the payload coupling; a p ratus tmy be bottom weighted si? "that It ^' iemains ^" m a desired vertical- orientation, and does not tilt.

jOO f The package ased for the winch tip/pick o operation may be m aerodynamieally sha ed tote with a reinforced snap-in handle (e.g. made out of plastic or other materials .sitch as fiber), although otber sbaped payteads may also be- used. The handle of the payioad attaches the payload to the hook of a pay load coupling apparatus and its slot or opening Is shaped to allow for a reliable passive release.. The handle also may include two smaller openings for Soeklng pim. The relnforcerBent of the handle is beneficial to teansrait the totqae from -the capsule into the package durkg the a!l ftraerjt rotation. The package itself raay he made o«t of cardstock and have m infernal tear strip, ^' TJ*e tills fiber tape tear strip may tan along die perimeter of one package side and. enables the ertstomer t open the paeiiage easily after delivery,

{ 92 When the ay load ts-sviached up an alignment is completed the payloa is piilled into a recessed restraint slot in the fuselage of the OAV _» using the additional vertical travel of the capsule in its receptacle . The recessed restraint slot matches the shape of the upper portion, of the payload and stabilises it during eriiise flight,, preventing any excess side io side or back and forth sway rnetion. Th recessed restrain slot is also eoaipietely recessed Into the fuselage and has o protruding parts, allowing for good ae ody amic on the return flight (after the package as beers delivered).

i fy Th present enibodlrneuts provide a highly integraied winch-based pickup and delivery system for UAVs, A «t*mher of significant advantages may be provided. For example, the ability io pick up nd deliver packages without the need for landing is provided. Th system is able to winch u a package with the aircraft hovering.. There also may he no need fo infrastructure at the niercha»t o customer in certai applications. The advantages Include high .mission flexibility- and the potential, for limited or no htirastmemre installation costs, as well as increased flexibility iii payload geometry.

II, Illustrative LTomaitiie Vehicles

fiKI94| Herein, the: terms "nnmaaned aerial vehicle" and "UA " refer to any autonomous of semi-autonomous vehicle that is capable of performiti some fonctioris without a physically present human, pilot.

JiifH9Sf A tJAV can take various farms. For example, a fJAV may take the form of a fixed-wing aircraft, a glider aircraft, a tail-sitter airemft, a jet aircraft, a ducted fen .-aircraft, a lightcr-than-air dirigible such as a blim or steerahie balloon, a rotoreraft such as a. hehcoptef or mullicop er, and or an orsithopter, among other possibilities. Farther, the terms ^' "dtepne."

examp le U AV 11 0a, stabilizers 1108 are -shows attached to the rotor supports 1. 1.10.

j¾099| During flight, the UAV l !OO may control the direction a¾d or speed of Its movement: by controlling lis pitch, roll, yaw, and or altitude. For -exainpls- the stabilizers I: JOS may iue!ude one or more rudders: 11:08a tor eontrolllftg the UA V's yaw, and the wing 1.102 may include one or mom elevators for controlling the tJAV's pitch and/or one or more ailerons 1 102a for controlling the UAV's roil. As another example, increasing or decreasin the speed of all the propellers simultaneously can result in the UAV 1 100a increasing or decreasing its altitude _* respectively,

{{Ϊίθ0 Similarly,.. Figure IB shows anotlier example of a feed-wing UAV 1,20. The fixed-wing UAV 120 includes a fuselage 122, two wings 124 with an airfoil-shaped cross section: to provide lift for th ^' UAV 120, a ertical stabilizer 126 (or fin) to stabilize the ptase's yaw (torn left or right), a . ^■ horizontal stabilizer 128 (also referred to: as a elevator or tailplane) to stabilize pitch (tilt «p or down), landing gear 139, and a propulsion unit 132, whien ean include a motor, shaf , arid propeller.

}01M| Figare iC shows an: example of a UAV 140 with a propelier in pusher coB iguraiiori. The term "pusher ^* refers to the feet that a propulsion unit 1 2 is mounted at the baek of the UAV and '' oshes' ⁵ the vehicle forward, m contrast to ihe propulsion wait being mounted at the front of the VAV. Similar to the description provided for Figures ΪΑ and IB. i ure iC depicts eouuuon structures used in a pusher plane, i cluding a fuselage 144, two wing 146, vertical stabilizers Ϊ4Β, and ie: propnislou unit 142,. hich e&n include a motor, shaft and propeller.

J&1021 Figure ID shows an example of a tai l -si iter UAV 160. In the illustrated example, the tail*&ttter UAV 1 0 has fixed wings 162 to - pr vide lift and allow the UAV 1 0 to glide horizontally (fcg,, along the x-axi-s, in a. position that is approximately perpendicular to ¾e position show in Figure I D). Ffowever, the Used wings 1.62 also allow fee tail-sitter UAV 160 to take off and land vertically on its own.

0l03f For example, at a launch site, the tail-sitter UAV 160 may be positioned vertically (as shown) with its fins 1.64 and or wip 162 resting on the ground: and stabilizing the UAV 160 in. the vertical position. The tail-sitter UAV 160 may then take off by operating Ms propellers 166 to generate an upward ^' ferusi (e.g , thrust that is generally along the y- axls :. Gnce at a. suitable altitude:, fee tail-sifter UAV 1 0 « · use its flaps 168 to reorient itself in a horizontal, position, such: that its fuselage 170 Is closer to being aligned, with fee axis than the y~axis. Positioned horizon tally, the ptopeiletS: 166 may provide forward thrust ^' so that the tail-sitter UAV 160 can :iy in a similar manner as a typical airplane.

|01CH| Marry variations on the illustrated fxed- ing UAVs are possible, For instance, feed-wing UAVs may include more or fewer propellers, and or may utilize a ducted fan or mtftipie ducted fans for propulsion. Farther, UAVs with more wings- (e.g., an -configuration with tbuir wings), with fewer wings, or. eve with no ings, are also possible.

|Q!65J As noted above, some embodiments uury involve other types of UAVs, is addition to or in fee alternative to fked-wing UAVs, For Instance, Figure IE shows an example of a rotorcrafi that is eonimonly referred to as a muitieopter ISO. The mnlticopfer 180 m y also be referred o as a quadeopEer. as it includes f0¾r rotors 182, It should be understood thai exauiple embodiments -may involve a rotororaft with more or fewer rotors

specific route to take between the two locations, specific flight controls to achieve the routs and avoid obstacles while navigating; the route,, and so on.

ieSJ Mom generally, it should be understood: that the example OA s described herein are not Intended, to be limiting, ^' Example embodiments ma relate to, be implemented within, or take the htm of. any type of ^' nmanned aerial vehicle,

ill, illustrative JAV Compeaente

QI 9 Figure 2 is a simplified block diagram illustrating components of a AV 200, according t an example embodiment U V 200 nia -rafce the form of, or be similar in form to, one of the UAVs 1 )0, 120, .1.40, MO, and ISO described in reference to Figures 1 A- IE. However, UAV 200 may also take other forms. |0i #| UAV 200 may include various types of senso y and may iiielude a computin

.system configured to provide the ftmeiioiiaiity described herein. In the illusiraied embodhnent, the sensors of UAV 2© include an. niert measwmi rtt unit (IMU) 202, uitesonic serisor(s) 204, and a GPS 206.. arnong otliet poss le sensors and sensing systems;

I 11) .In the iiiustrate embodiment, .UAV 2(50 also includes one or more processors

208. A processor 208 may be a general _' purpose processor or a special . ^' purpose processor (e.g., .digital signal processors, appiicaiioFi specific integrated circnits, etc). The one or snore processors 208 can be c nfigured to execute eompiiter-reada e progratn instructions 312 ¾at are: stored in :th data storage 210 and are executable to r vide the ¾¾etionaity pi a, UAV described herein.

|0l 12) The data storage 21.0 may include or take Ac form of one of. mote eomputer- readabk storage media that can be read or accessed by at least one processor 208. The one or more eonipuie«»readahle storage media cat* include volatile and/or nonvolatile storage components, SM!I as optical, magaeiic, organic or other memory or disc storage,; ich sail be integrated in whole or in part: with at least one of the one or more processors.208, In some embodiments,, . the data storage 210 can be. implemented; usin a single ptiy steal device {e.g., one optical, la&gnetise, organic or other memory or disc storage onit), while, in other embodiments, the data storage 210 can fee implemented using two or more physical ..devices. 01J3) As noted, the data storage. 2ΙΘ can include coinpister-readab!e program insirnetions 21 and perhaps additional data, such as diagnostic data of the U V 200. A stieh, the data storage 210 may include p:rogmn instructions 212 to perform or facilitate some or all of the UAV fanctionalit described herein. For i stance, in the illustrated embodiment, program Instmetions 212 include a navigation. module 214 and a tether control module 216.. A. Sensors

f 011 1 i at). ilhiSttatiYC embodiment, IMU. .202 may include both an aece}eroi»eter and a gyroscope, which may be «sed together to determine an orientation of the UAV 200. I» particular,, the aeceleroinetor can measure the orientation of the vehicle with respect to earth, while the gyroscope measures Ac rate of rotation arotirsd an axis. iMUs are commercially ■available in low-cost, low-power packages. For instance, an IMU 202 may take the form of or include a miniaturized ieK BleettoMeehariical. System (MEMS) or a ManoEIeetroMeckanieal System. (MEMS). Other types of IMUs ma als be utilise .

fOilSf An IMU 202 may include other sensors, in addition to aecelerometers and gyroscopes, which, may help to. beiteF determine position and/or help to increase autonomy of tiie U V 2 . Two examples of such sensors are magnetometers and pressure sensors. In some embodiments,, a UAV may include a !o sa e , digital 3*axis- ^gttetoflneter- which can ^' fee used to realize a orientation -i»depe¾de»t electronic compass for accurate eading Information, However, other types of ma netometers may be utilized as Weil, Other examples are a so possible. Further.. Bot that a JA V could inelnde some or all of the above-- described inertia sensors as separate copiponerits from an IMU,

|01 i£g UAV 2 9 may also include a pressur sensor or barometer, which can be used to determine the altitude o the UAV 200. Alternatively, oilier sensors, such as sonic altimeters or radar altimeters, ean be used to provide an indication of altitude, which may help to improve the aeeiirasy of arid/ot prevent drift of an. IMO,

l&l 17 Irs a farther aspect, U A M m y Include one or more sensors that allow tie UAV t sense objects in t e environment. For instance ln the illustrated embodiment,, UAV 200 includes ultrasonic sensor(s) 204. Ultrasonic sensor(s) 204 can. determine the distance to an. object by geaeratrrig. sound waves and determining the time interval between transntission of the wave and: receivin the correspondmg echo off an object . A typical appticatlosi of an. ultrasonic sensor for unmanned veMeles or !MUs is low-level altitude control ami obstacle: avoidance. Art ultrasonic sensor can also be used for vehicles that need to ho e at a certain height or need to be ca able of detecting ebstaeie& Other systems can fee used to determine, sense the presence of _* -and/or dterinme. the distance to nearby objects, such as a light detection and ranging (LiDA t) system, laser detection and ranging f LADAR) system, and/c a» infrared f ror ard-IoOking infrared (FOR) system, among other possibilities, fCSi SJ In some emfeodimerits, UAV 200 :may also include one or more inia ing s-ystem(s) ₄ For example, one or more still and/or video cameras may be tttilized by IJAV 20 to capture image dat from the UAV ' environment. As a specific example, eh.arge ¾upied device (GC&) cameras or complementary metal^oxide-sernicondttetor (CMOS) cameras can be used, with- unmanned vehicles. Such imaging sensor(s) have .unmeroiis possible applications, stick as obstacle avoidance:, local ization techniques, ground tracking for more accurate navigation Ce,g b -applying optical flow ^' tqehnkfues to images), video feedback, aftd'br image recognition and processing,, amon other possibilities;.

101.191 UAV 200 may also include a GPS receiver 206. The GPS receiver 206 ma be configured, to provide data that is typical of well-known GPS systems, such as the GPS coordinates -.of the UAV 200, Such GPS data may he -u ilised by the UA. 200 for various functions. As suck the UAV ma «se it GPS receiver 206 to help navigate to the caller's location, as Indicated, at least in part, by the GPS coordinates provided by their mobile ds vise. Other examples are als possi ble . B» avigation utl Locution Determmistian

}Θ12Θ| Tiie 8a«gai ¾ib wiodule 21 sy\ ?ov e fnneiio&aiity t¾at allows the UAV 2S0 to,, e.g.* move a ut ft$ environment and reach a desired location. To do so, the natation module 214 may control the altitude andor direction of flight by eosire!lisg the mechanical features of the UAV thai affect flight (e.g.,. its rudderis),. elevatoris), aileronCs), and/or the speed of its propclleris}}.

$1.21 J : In order to navigate the UAV 2¾0 to a target location, the myigatiop mo ule 214 may mpie mi various riayigacioii teehnicjwes, sneh as map-based navigation and ioeali¾ation¾ised navigation., for instance. With, map-based riavigatiofi _s the UAV 201 may be provided with, a nisp of its emdronme&t, whi h may thai be used to navi ato to a particular locatio on the map. With loca!tt tioa-base i n vi ation, the UAV 200 may be capable of navigating i m unknown mvir fttnent usin localization. Localization-base navigatio -may involve the UAV 20 buil ing its own map of its environment and calculating its position within tfee map and/or tlie position of objects i the en Onn erft. For example, as a UAV .208 moves throughout its. environment, the UAV 2 0 «¾y contirmously use iocalizafios t update its map of the e«Yifoni»eet. This continuous mapping process ma be ieferred. to as simultaneous localization: and mappin (SLAM). Other navigation techniques may also be ttii!i¾ed.

}M22| Its some embodiments, the navi ation module 214 may navigate using a teehnlque that reies o way points. In particular, waypoints are sets of coordinate that identif points in physical space. For instance, as ai -navigation, avpokt may be defined b a certain latitude, longitude, and altitude. Accordingly,, navigation module 214. may cause UAV 20 to move from waypoint to waypoint., in order to ultimately travel to a final destination (e.g., a final waypoint in a setpeiiee of waypoints),

f 123J I a forther as ect the navigation rnodnie 214 and or other components, and Systems of the UAV 200 may be eoni%«red for ^M 1.oiCidisatioh ^w'' o ^' more precisel navigate to the scene of a target location. More specifically, it ma be desirable is certain situations for a t A to be within a threshold distance of the target location where a payload 228 is being delivered by a UAV (e,g., within a lew feet of the target destination). To this end, a UAV may use a two-tiered approach in which it rises a more-general location-determination technique to navigate to a general area that is associated with the target location, and then use a more-refined iocation-determination technique to identif and/or navigate to the target location withi the general area. {0124} For example, the UAV 200 rosy navigate to die general area of a target des matson where a payload 22S is being delivered ^' using waypoi s arid/or map-based navigation. The UA V may .ihea switch to a mode in which it utilizes a localization process to locate and travel to a ore specific location. For instance, if the UAV 280 is to deliver a payload to a user's horne,. the AV 200 may seed to be- substantially close to the target location is order to avoid deli very of the payload to uadesired areas (e.g.,. onto a roof, into a pool _* oato a neighbors property _* , ete.); However, a GPS signa may only get the -UAV 200 so far ¾-g _i5 wthm a. Woc¾ of the user's borne). A more precise iocatiOE-defent!iii iior} ^• tech ique may diets fee used to find the specific target location,

l&i jS I VarioMS types of !ocarJon-determ atiOn teehniqwes -ma be use to acconmlisn ioea&afeo of the target delivery location once th UA 200 has navigated to the general area of the target deliver location. For instance, the UAV 200 may be equi d with one or rnore sensory systems; -soeh as, for example, ultrasonic sensors 204, infrared sensors (not, ■Shawn), a d/or other sensors, which, may provide input that the- navigation niodnle 214 utilizes to navigate autonomously or senii-anto«onuo«siy to the speeifie target location.

0126 As another example, once the UAV 20 reaches the general are of the target

■delivery location (or of a Mo ving; salject such as; a pers n or their mobile device), the UAV .200 m switch to a "O ^hy-wire" mode ere it is controlled, at least in part _* , by a remote operator, te ca navigate the O V 290 to the specific target location. To tfns end, sensory data Irorn die DAY 200 may be sent to the remote operator to assist theni in navigating the UA V 200 to the specific location.

|0327| As yet another example, the UAV 20 niay include a modul that is able to signal to a passer-by for assistance in either reaching the speeifie target delivery location; for example, the UAV 200 may display -a visual message equesting swell assistance in a graphic display, play m audio message or tone throngh. speakers to indicate the need for sweh assistance:, among other possibilities, Sitch viswal or audio message might- indicate that assistance is needed is delivering the U AV 200 to a particular person o a particular location, and misfit provide inf rraation to assist the passer4>y io deb vers ng the UAV 200 to tne person or location (e.g, _s a description or picture of the person, or location, and or the person or location's name), among other possibilities. Such a feahsre can he nsefkl in a scenario in which, the UA is unable to use sensory fanetioris or another iocation-de ermmation technique to reach the specific target location. However., this teatete .ts.-fcot limited to sneh scenarios: J 12S| lift softje embodiments, once the U V 200 arrives at the eneral area of a target delivery location, the UAV 201) may tiffin a beacon from a user's remote dsviee {e.g. _¥ the user's mobile jshotse) to locate the person, Sue va beacon may take various f mis. As as example, consider tile scenario ere a remote device,, such as the mobile phone of a person who requested a UAV delivery,, is able to send oitt directional signals (e.g., via an F signal, s light, signal and/or an audio signal). In this scenario, the UAV 200 may be configured to aavigate ^: b ''sourcin ' ⁵ saeb directional signals ~ m other words, by deteraiiaiug: where the signal is strongest aad Mvigating■accordingly:. As another example, a white device can emit a frec eney, eiiier in the .human ra¾ge or outside the■.human ranges aad the U .200 can .listen for that rmqueney and navigate accordingly-. As a relate example, if the UA 200 is listening for s kes commands, then the UAV 200 eoukl ytiiize ^■ spoken, statements, such as 'Tni over here!" to source the specific location of the person requesting delivery of a payioad.

pi29| n an alternative arrangement, a na igation module may be implemented at a. remote eempuiin device, which conimimieates wirelessi with ^' the UA V 200, The remote ^• camjsitia device may reeeive data indieatmg the operational state of the U AV 200, sensor dat irot the OAV 200 mat allows it to assess the environments! conditions bein experienced fey the UAV 20 , and/or location information for the UA V 200. Pr i ed with Sttch iatornaaiion,. the remote computing device stay determine altiiudinal and or directional adjustment that should be made by the UAV 200 and/or determine how the OAV 200 should adjust its nieehauicai features (e.g , its rudderfs), e|¾vatof s) _t ai!ero«{s an&¾r the speed of its propel ler(s)) in orde to et ic ate such movements. The remote computin system may then communicate such adjustments to the U V 200 so it can move in the determined manner.

C Coniitititiication Systems

|0130 In a further aspect, the UAV 200 includes one or more communication systems 218. The communications systems 218 may include one or tnore wireless imerfaces and'bv one or more wireline interfaces, which allow the UA 260 io eornmum ^' caie via one or more networks. Such wireless interfaces ma provide for communication under one or more wireless eonmtnnicaiion protocols, such as Bluetooth, WiFi (eg., an. IEEE 802.11. protocol), Long-Term Evolution (LTE , iMAX (e,g. _s aa IEEE 8 ⁽ )2; 1 & standard), -a :radio«fi«q«ency ID (RFlD protocol, near-field communication (NF ¾ and/or other wireless commtrnication protocols. Such iretiue interfaces may include an Ethernet interface, a Universal Serial Bus (USB) interface, o similar interface to communicate via a wire, a twisted ai of wires, a coaxial cable, a¾ optical link, a fiher-optie link, or oth r physical connection to a wire!kte network.

}ΘΙ3ϊ| IK some embodiments, a OAV 200 may ifiehide c amMsi aiioii systems 21 that allow for both short-range eommanleatiori and long-range cemmnnicatiorf. Per exam le, the UAV 200 may be configured for short-range communications trsing Bluetooth, and for long-range commtaiicatioas under a CDMA protocol In. such an enrbodiment the UAV 200 may be configured to taction as a "hot spot;" o in other words, as a gateway or proxy between a remote support device and. one or more data. nehvorks,. such as a cellular network anqVor the lifclM. Configured as sneh, the IJAV 200 may facilitate data communications that the remote support device would otherwise be tioable to perlbnii. by itself

|1132} For example., the UAV .200 may provide a WiFi eenmeeiiou to- a remote device, and ^' serve as a proxy or gateway to a cellular service provider's data network, -which, the UAV might ^' c nnect to -under an LTE or a 3G protocol for instance. The UAV 200 could also serve- as a prox or gateway to a high-aititude balloon network, a satellite network, or combination of these networks, among others, which a rernote device might not be able to otherwise access,

B, Fewer Systents

(#133] in a further aspec¾ the UA 200 may include -power system(s) 230, The power .system 220 may include one or more batteries ' fo« . _. providing power to the U AV 20O, Is one example, the one or more batteries may be rechargeable and each battery may be recharged vi a wired eo&neetk® bet een the battery and a powe supply and/or via a wireless charging system, such as an inductive charging s stem that applies art external, time- varying magnetic field to -an internal battery,

I, Payfoad Delivery

( 13 j The UAV 200 m&y employ various systems and coBfiguraiious in order to transport and deliver a payioad 2:28. in so i isnplementaiions. the payioad 228 of a given UA V 200 may include or take the fwm of a ''package" designed to transport various goods to ■a target, delivery location, For exa ple, the U ^' A V 200 can. include- a compartment, in Which an item or item may be transported. Such a package may one or mo e food stems, purchased ^' goods, medical, items,, or any other objeet s) ving a size and weight suitable to be trsusported. be&ve n two locations by the U A V, In other embodimefits, a payioad 22$ may -.simply, fee the one or more items that are being delivered (e,g,< without pacfeage hoiisin the items) . f0135f ϊύ some embodiments, the pay!oad 228 may be attache to ine UAV and loca d substantially outside of the UAV during some or ail of a flight by the UAV. For example, ike package may be tethered, or otherwise reiea^ahSy attached belo the UAV during Sight to a target location, in an eaihodiment where a package carries goods below the UAV,. the package may include various features that prefect its contents from the mwonment, reduce aerodynamic drag on the system, and prevent the cot) tents of the package from, shifting during UA fligh

J9136| For instance, when;: the pay load 228 takes the form of a package for transporting: Items, the package may include an eater shell constructed of water-resistant cardboard, .plastic, or -m other ligh tweight and water-resistant ..material Further, in order to reduce drag, the package may feat are sniooth surfaces ith a pointed front that reduces the frontal cross-seetional area. Further, the sides of the package may taper .from a wide bottom to a narrow tap, wiiiei¾ allows tlse packa e to serve as a narrow pylon ^' tbat reduces iuterfereiiee effects on the wing(s) of the UA V, This may move some of the frontal area and volume of the package away from the wiug s) of the UAV, thereby preventing the rednciion of lift on the wingCs} cause by the package. Yet fiirther, in some embodiaieats, the outer shell of the package may be consh icted horn a single sheet of material in order to reduce air gaps or extra material, both of which may increase drag on the system,: Additionally or alternatively,, the package -may lae!tide a stabilize to dampen package fette This reduction in flutter rnay allow the package to have a: less rigid coaneetion to the UAV and may cause the contents of the package to shift less during flight.

iJTf In order to deli er the payioad, the iJAV may include witteh system. 221. controlled by the tether control module 216 in order to lowe the payload 228 to the ground white the UAV hovers above. As shown in Figure 2, the winch system >22.1 nsay include a tether 224, and the tethe 224 ma be coupled to the payload 228 b a payload coupling, apparatus 226. The tether 22 may he wound on a spool that is coupled to a motor 222 of the UAV, The motor 222 ma take the form of a DC motor (e.g,, a servo rooter) that eaa he actively controlled by speed, controller. The tether control module 216 can control the speed controller to cause the motor 222 to rotate the spook thereby unwinding or retracting; the tether 224 and lowering or raising the payioad _/ Coupiiu apparatus 22h. la practice, the speed controller may output a desired operating rate ( g a desired R ) tor the spook which m y correspond to the speed at whicn the tether 224 and payload 22B shordd he lowered towards the ground. The motor 222 may then rotate the spool so that it maintai s the desired operating rate. [0138} Is order t control the motet 222 via the speed controller, the tether control

■module 2ϊβ may receive data from a speed sensor (e«.g., an encoder) configured to convert ¾ mechanical position to a representative analog or digital signal la particul r, the speed sensor ma include a rotary encoder that may pro vide information related to rotary position (and/or rotary movement) of a shaft of the motor o th spool coupled to the .motor, among other possibilities, .Moreover, the speed sensor may take die form of m absolute encoder arid or an incremental encoder, among others. So in an example imp!enrentation, as rhe motor 222 causes rotation of the spoo! _S: a rotary encoder may he used, to measure this rotation. In doing so, the rotary encoder may be ^' Used c<¾¾ ei† . ^· ¾· ·ρβ§.¾; ¾ι to an analog Of digital electronic signal »sed by the tether control modiste 216 to determine the ni nM of rotation of the spool from a fixed reference angle and'or to an analog, or digital electronic .signal -that, representative of a new rotary position, among other options. Other examples ace also possible.

pi 39 i Based on ike- data froni the speed sensor, the tether cositol modttie 216 may determine a. rotational speed of the motor 222 and/o the spool and responsi ely control the motor 222 fe.g., by increasing or decreasing an electrical earreni supplied to the motor 222} tie ca»se the ioml-s ^dofihs- ttotor 222 to matc a desired speed. When, adjosting ttie motor conCTt, the tnajpitude of the enrrent adjustment raay be based n a proportional- jutegra -deriYaiiv (FID) calculation using the determined and desired speeds of the motor 222, For instance, the magtiitede of die current adjustment ma be based on a present difference _* a past difference (based on aecumii Sated error over time), and. a future difference (based on current rates o change) between the determined and desired speeds of tile spool. Θ;Ϊ4Θ| In some embodiments _S: the tether control module 216 may vary the rate at whteh die tether 224 and paylea : 228 are lowered t the ground. For example, the speed controller may change the desired operating rate according to a variable deployment-rate profile and/or in response to other factor m order to change the rate at which the payload 228 descends toward the groond. To do so, dre tether control module 216 may adjnsf an amount of braking or an. a:tnonnt of friction that is applied to the tether 224, For example, to vary the tether deployment rale, the UAV 200 may inelnde friction pads tha can appl a variable amount of pressure to the tether 224, As another example, the UAV 2C 1 can inelnde a motorized braking system that varies the rate at which the spool lets out the tether 224. Such a braking ystem may take the f rm of an eleeiroinecharteai. system is which tire motor 222 operates to slow the rate at which the spool lets out the tether 224. Further, the .motor 222 ma vary the amotmt by which it adjusts the speed (e.g., fee RPM) of the s ool, and thus may vary the deployment rate of the fetfeer 224, Other examples are; also possible.

j0i41| In some embodiments*,, the tether control module 21 may be eotefigured to limit the motor current supplied to the motor 222 to a maximum value. With such a li it placed OH die motor ctirrent _> there may be situations where .fhe motor 222 cannot operate at the desired operate specified by the speed: controller. For instance, as discussed in more detail below, there may ¼ situations where the speed■controller specifies a desired operating rate at which the motor 222 should retract the tether 224 toward the UAV 200, but the moto current may be limited such that a large enoug o nward foree on the tedier 224 would counteract the retracting force of the motor 222 and cause the tether 224 to unwiftd. instead. And as further diacessed below, a limit on the motor eoorent may be imposed and/or altered depending on an operationai state of the UAV 200.

|0i42| ΪΒ some embodiments, the tcttser control module 216 ma he configured to detcrmme a states of the tether 224 and or the payload 22% based on the aniotmt of etareftt supplied to the motor 222. For instance, if a downward forte is applied to the tether 224 (e.g., if the payload 228 Is attached to the tether 224 or if the tether 224 gets snagged on an object when redacting toward the UAV 2CM ⁾ }, the tether control module 216 may need t increase the motor current in order to cause the determined rotational speed of the motor 222 and/o spool to match the desired speed. Similarly, when the downward force is removed froiit the tether 224 fe.g. _y tipon deliver of the payload 228 or reraovai of a tethe snag), the tether control modiste 216 may need to decrease the motor current- in order t eaiise the determined rotational speed of tl e motor 222 and/or spool to match the desired speed. As sncli, the tether control module 216 may be configured to monitor the current snpplied to the motor 222. For instance, the tether control module 216 could determine the motor current based on. sensor data received from a current senso o the motor or a enrrent sensor of the power system 220. in an case, based on the current snpplied to the motor 222 _? determine if the payload 228 is attached to the tether 224, if someone or sornedung is pulling on the tether 224. and/or i the payload conpiiiig apparatus 226 is pressing against, the UAV Wti after retracting the tedter 224. Other examples, are possible as well,

(01.431 During delivery of the payload 228, the payload coupling apparatus 226 can be c nfigured to secure the payload 228 while being lowered fro tfee; ^" UAV b the tether 224, and can be fether cottfsgnred to release the payload 2 8 upon reaching ground level The payload coupling apparatus 226 can then he retracted to the UAV by reeling in the tether 2.24 using ti¾e motor 222. f0t44J In some implementations, 'the payload 228 may be passively released, once it is lowered to the roraA For xampl , a passive release mechanism tnay inclnde ofte or more swing axms adapted to retract into and extend froffl a housing. An extended ^■ swin arm may form a hook on which the pay load 228 may be attached. Upon lowering the release .mechanism and tie payload. 228 to the .■ground: via a tether,, a gravitational ioree as well as a downward inertia! force on the release raecbanism ma cause the payload 2$ to detach firom die hook allowing die release mechanism to be raised upwards toward the UAV. The release mechanism may further include; a spring mechanism that biases the swing am) to retract into the housing when there are no m the external forces ors the swing arm. For instance, a spring ■may .exert -a force ^' - -oh the .swia mm thai pushes or pulls the swing ao« toward the housing Sttch that the swing arm retracts into the housing once the weight of the payload 228 no longer forces the swing arm. io extend from the .housing. Reiraeting the swing arm into the -housing may reduce the likelihood of the release mechanism snagging the payload 228 or oilier nearby objects when raising the release iuechaoisrti toward, the t?A upon delivery of the payload 228.

}ΘΙ45§ Active payload release nmehauistns are also possible. For example, sensors such as barometric pressure based altimeter and/or acceierometers may hel to detect ike position of the release nieehautsnj (and the payload) relative to the ground, l¾ta from the sensors eas be cornmisnicated back to the UAV aud or a control system -over a wireless link and used to hel in determining when the release mec anism has reached: ground level {e.g., by detecting a measurement with the aeeelerornefer that is characteristic of grouud impact). In other examples, the ^' UAV .may determine thai the paybad has reached, the ground based on a weight sensor detecting a threshold low downward force on the tether and/or based on a threshold low measurement of power drawn by the winch when lowering the payload.

| i46 ^' f Other systems and techniques for dehveriag a payload,. in addition or in the alternative to a tethered delivery system are also possible. For example, a UAV 200 could include an air >ag drop system or a parach«te drop system. Alternatively, a UAV 200 canyirt a payload could simply land on the ground at a delivery location. Other examples are also possible,

IY< IJhjstraiive U V Beptoyraeintt Systems

|θί47| UAV systems may be implemented m order to provide various UAV-relsied services. In particular, l)AVs may be provided at a number of different launch sites that may be irr cornmanlcation with regional and ρτ centra control systems,. Such a distributed tlAV system _. may allow IJ AVs to he muckly deployed to provide services across a large geographic asm (e,g. _} that is much arger than tfafc flight raruje ¾?£ any single UAV), For example, UAVs capable of carrying payioads ¾f be d siriba ed at a timber, of launch Sites across a large geographic area (possibly even throughout an enti e coustry, or e¾) worldwide} _* is order to provide on-demand transport of various items to locations throughout the geographic area. Figure 3 is a simplifiesl block diagram illustratin a distributed UAV system 300, according to an example embo iment

Qi 8J In the iltetrative OAY system 300, an access system 302 ma allow for interaction ith _s control of, and/or utilizattoa of a network of UAVs 304. in some embodiments, an. acces system 302 may te a computing system that allows for human- coutro!led dispatc of UAVs 304, As sneh, the control system may include or otherwise provide a nser interface through which a user can. access and/or control the UAVs 304.

f0l49| In some embodiments, dispatch of the UAVs 304 may additionally or alternatively be accomplished via, we or more automated, processes. For instance, the access system 302 may dispatch one of ihe UAVs 30 to transport a payload to a target location,: arid, die UAV may autonomously navigate to the target locatio by utilizing various on-board sensors., such as a Gi*S receiver aad/or other various navigational sensors.

|015 { Further, the access -system 302 may provide for reinote operatioa of a UAV.. For Instance, the access system 302 may allow an operator to control the flight of a UAV via its user interface. As a specific exauiple, au operator aiay use the access system 302 io -dispatch a UAV 304 to a target location. The CJAV 304 atay then autonomously navigate to the general area of the target location. At this point, the operator may use the access system 302 to take control of the UAV 304 and navigate the UAV to the target location (e,g,, to: particular person to whom a payload is being transported). Other examples of remote operation of a U AV are also possible,

fOIMf n aa illustrative embodiment, the UAVs 304- may take various forms. For example,, each of the UAVs 304 may be a UAV such as those illustrated in Figures S A- ! E. However, UAV system 300 may als utilize oilier types of UAVs without departing -ftom the scope of the inveation. in some impfemeatatioas, all of the UAVs 304 may be of the same or a similar eoufignratiou. However, in other implemeniatioiis, the UAVs 304 may iiicltide number, of different types of UAVs. For instance, the UAVs 304 m y include a number of types of UAVs, with each type of UAV being configured, for a diffcent type or types of payload delivery capabilities,

fOiSff The IJA V ^' .system. 300 may furthe inelude a reraoie device 306, which may take various forms. Generally, the remote device 306 may he any device thron h which a direct sr indirect request to dispatch a OAV can be made, (Mol tSjat aft iftdireet request may Involve an commtstiicatioa. thai t be respfcs&d to b dispatching s OAV, suc as ra estirig package delivery), ¾ as ^■ example embodiment the remote device 306 raiay be a mobile: phone, table computer, lapto computer, personal computer, or aay netw rk- connected computing device. Further, in some instances, t ie remote device 306 «iav not be a computing device. As an example, a standard telephone, win allows for co ntuek ^; ation via plain old telephone service (POTS), may serve as the remote device 306, Other -types.- of remote devices are also possible.

(01531 Further, die remote de ice 306 may be configured to eot tnmieate wit access system 302 via one or more types of eo nnieatioo neiwotkfs) 30¾, For sxarapie, the i'emoie device 306 may eearatimcate wit the access system 302 (or a husnars operator of the access system. 302) by communicating over a POTS network, a cellular network, and/or a data network such as the inte et, Other types of networks may also he utiliaed.

iS | In some embodiments, the remote device 3 6 rosy be configured to allow a. user to reques delivery of one or mere items to a desired location _* For example, ¾ «ser could request UAV delivery of a package to their home via their mobile phone, tablet, or laptop. As auother example, a user co M request namic delivery i& wherever they are located: at th time of delivery. To provide such dynamic delivery, the UAV system 300 may recei e location irifenriatioji (e.g. _s GPS coordinates, etc.) rprn the user' mobile phone* or aay other deviee on the nser person, such that a tlAV ean navigate to the user's locatiori {as iridieated by their mobile phone),

01:55] in an illustrative arraugemeRt, the eentfal dispatch system 310 may be a server or group of servers, which is configured ^' to receive dispatch messages requests and/o dispatch instructions- front the access system 302, Such dispatc messages stay reques or instruct the central dispatch system 310 to coordinate the deployment of tlAVs to various tar§ei locations. The central dispatch system: 310 may be Further eorsfigured to route suck requests or instructions to o«e or roc-re local dispatch systems 312, To provide such mnctionslity, the central dispatch system 310 may eommursieate with the access system 302 vi a data network, such as the Internet or a private network that is established, for communications between access systems and automated dispatch systems,

0156] is the illustrated configuration,, the central dispatch system 310 may be configured, to coordinate the dispatch of OA V$ 304 from a -number of different local dispatch systems 312, As sneh, tire eeiJtral dispateh system 310 may kee iraek of which li AV 30 are located at which local dispatch systems 312, which UAVs 304 are enrreatiy available for deployment, a¾d or whic services or operations each &t the IJAVs 304 is configured for(m the event that a UAV fleet meludes tntdtiple types of UAVs eoafigiired for dli&reai services and/or operations). Additionally or alternatively,, each local dispatch system 312· may be ceni%ured: to track which of ts associated IJAVs 304 are c«n¾n available for deploynieat and/or are eurrefttl the midst of item transport,

01S?i In some eases, w ea *he central dispatch s stem 310 receives a request for OAV-related service (eg., hausport of an item) f&sm di access system 302, th central dispatch system 310 may select a specific UAV 384 to dispatch. The; -central dispatch s stem 310 may aceordisgiy instruct the local: dispatch, system 312 that is associated with, the selected UAV to dispatch the selected UAV. f he local dispatch system 3 12 may men operate its associated dep.to ie i: system 314 to laiaieh the selected UAV. in other c se j the eeairai dispatch system 310 ma forward a request lor a UAV~related service to a local dispatch system 312 that is ne r the location where the support: is requested- an leave the selection of 8 parficular UAV 304 to th local dispatch system: 31-2,

{0158} ^' 1» an example c nj ratio , the local dispatch system 312: may he impieaieaied as a eo pnttrig system at the same Ideation as the deployment sysiea¾(s) 314 thai: it controls. For example, the local dispatch system 12 may he implemeiited fey a c mptiting- system installed ¾t a building _* , m&h. a warehonse, where the depioytnent systeniCsJ 314 and l ⁾ AV(s) 304 mat are associated with the particular local dispatch system 312 are also located. In othe embodiments, the loeal dispatch system 12 asa fee ttBpSetttersted at a location that is remote to its associate depioyirtent systcm(s) 14 and UAV(s) 304.

{©159} Numerous variations on and tematives to the iilttstxated configuration of the

UAV system 300 are possible. For example, in some embodiments, a user of the remote device 3iM could reques deliver of a package directly from, the central dispatch system 1 ,. To do so, ati application may he implemented on the remote device 306 that allows the user to provide mfbonaiian feg&rdirig a .requested delivery, and generate and send a dat message to request that the UAV system 300 provide, the deli very:, in such ^' a embodiment, the entral dispatch system 3 0 may include aatoniaied functionality t handle r ests that are generated by such an application, evaluate snch requests, and, it a$$m z, _: cec*ditt¾ie "«¾& ^· an appropriate local dispatch system 312 to deploy a UAV.

|O:16 f Fisi'thcr , some or ail of the ftmetionality that Is attributed herei to the central dispatch system 310,. the loeal dispatch sysierais) 312, the access system 3ΐ)2, and/or the deployraeut systernCs) 314 may be combined in a single system, implemente in. a more ^• fiie user ^account database 316 may include data, related to. or useful in pro vid ia UAV-ielated services. Typically, the user data associated im each user ^■ account is optionally rovided by an associated user arsd or is collected with the associated: user's pemusstoii.

further, in souie emhodiroeftts, a person .may be required to register for a user account with the IJAV system 300, if they wis to be provided with UAV-related services by the UAVs 3 J4 from tJAV system 300. As such, the user»account database 316 may include malrorizahor) iro¼nuaiion for a: given user account (e.g. ₅ a user xm and password), and/or other information t at rosy be used: to . authorise access to a user account.

( 1:§7j i some eiiihodiroesiSv a person may associate one or n¾ore of their devices with their user accounv such that they can access the services of UAV system 300, For example, when a persou uses, as associated mobile phone, e,g. _> to place a call to art operator of th access .system 302 or send a message requesting a UAV-rc!ated service to a dispatch system, the phone may be identified v a _^ a÷ u¾¾pe device identification nember, and the call or message rnay dien be attributed to the associated, user account. Other examples are also possible.

V, SS fttpfc Sy stew* »«d Ap aratus fm Payload Deli very

\®iM Figures 4A, 4B, and 4C show UAV 400-tjjat includes a payload delivery System- 410 (could also be reterred to as a payload delivery apparatus),, according to as esa pk euihodhBeitt. As shown, payload delivery system 410 tor UAV ΐ ⁾ ( ⁾ includes a tether 402 coupled to a spool 404, a payload latch 406, and a payload 1 coupled to the tether 402 via a payload coupling apparatus 412. he payload latch 406 can ftmetiou to alternatel secure payload 408 and release the payload 408 upon delivery. For instance, as shown, the payload latch 406 may take the form of one or more pins that can engage the payload coupling appara us 412 ie.g„ by sliding into one or mom receivmg slots h the payload coupling apparatus 2), Inserting the pins of the payload latch.40 into the payload coupling apparatus 412 may secure the payload coupling apparatus 412 within a receptacle 414 R the underside of the UAV 400, thereby preveiiting the payload 0S ixorrs being lowered fronr the UAV 400. in some erohodiraerjts, the payload latch 406 may be arranged io engage the spool 404 or the payload 40 rather than the payload coupling apparatus 412 s» order to prevent the payload 408 f om lowering, la other emhodiffleftts, the UAV 400 may not iuehide the payload latch 406, md the payload delivery apparatus rrsay be coupled dtrect!y to die UAV 40IX

ΪΒ some embodiments, the spool 40 ca function to unwind the tether 402 .s eh that the payload 4Q¾ can be lowere to the. round with the tether 402 and the payload cou ting apparatus 412 from UAV 400. The payloa 408 tiia itself be item for deliver ', and may be house within (or otherwise incorporate) a parcel, eoafalner, or other stiT.iCtr.sre that is -configured totcrfaee with the payload latch 406, la praetiee,. the payload delivery system 410 of UAV 400 may inaction to autonomously lower pay load: 408 to the ground la a controlled manner to facilitate delivery of the payload 408 oa the grouad while the UAV 400 hovers above,

|0i7flf As sho s ϊϊ Figere A, the payload latch 406 may he in a closed position

.(fc.g- _* piss engaging the payload coupling apparatus 412) to sol - the payload 408 against or close to the holtors of the UAV 400, or even, partially or completely inside the A¥ 400, during Sight■from a !aaneh site to a target location 420. The target location 420 m le a point la space directly above a desired deliver location. Then, when, the UAV 400 reaches the target location 420, the JAVs control system (e,g., the tethe coairol module 216 of Figure 2) aiay toggle the payload latch 406 to so open, position (e.g., disengaging the pias from the payload .coupling apparatus 412), thereby allowing die payload 408 to he lowered from trie UAV 400; The control .system may further operate the spool 404 (e,g,, by controlling iie rooter 222 of Figure 2j siieh that the payload 08, secured Jo the tether 40 b a payload couplin apparatus 412, is lowered to the ound,, as shown in Figure 4 .

|0ί7ϊ| Once the payload 408 reaches the ground* the control sys m roa contrane operating the spool 404 to lower the tether 402, causing Qver*rw& of the tether 402. Daring over-run of the tether 402„ the payload -coupling apparakis 12 may continue to lower as the p load- 08 ramains stationary on the gpottad.- The downward nioroeatnni asd or gravitational forces oa the payload coupling apparatas 412 ma cause: die payload 408 to detach frc«¾ the payload coupling apparatus 412 (e,g., by sliding off a hook of the payload coupling apparatus 412), After releasing payload 408, the control system may operate the spool 40 to .retract the tether 402 nd the payload coupling, apparatus 41,2 toward the UAV 400. Once the payload: coupling apparatus reaches or siears the UAV 400, the control system amy operate he spool 404 to pull the payload coupling apparatus 12 into the receptacle 414, sad the controi system ..may to gle the payload. latch 4 6 to the closed position,, as shows in Figure 4C,

|θ 172| la soise e bo hneBis, when, lowering the payload 408 -fio the U 00, the control system may detect when the payload. 408 and/or the pay load coapling apparatos 412 has ^' been lowered, to be at w near the ground based -oa an unwound leagth of t¼ _: tether 40 from the spool 404, Similar techniques siay he nsed lo deisraiine when the payload coupling apparatus 12 is at or near the UAV 400 when retracting the tether 402. As noted above, the UAV 400 m y include as -e coder for providing data i ieaiive of the rotation of the spool 404. Based on data from die encoder, fee cotitrol system may determine how many rotations the spool 404 has tmdergone and, based on the number of rotations, determine a length of tise tether 402 .that is iiweiind from: the spool 404. For instance, the control system may determine aft unwound: length of -the tether 402 by m kipiying the ntmiher of rotations of the spool 404 by the eirc»nife¾nee- of the tether 402 wrapped aroun the spool 404.. In some embodiiraents, s¾eh. as when the spool 40 is .narrow or when the tether 402 has a large diameter, the circ«m&reno€ of the tether 402 on the spool 404 may vary as the tether 402; winds or unpads frotn the tether, and so the control sy stent may ½ eonfrgured to _: account for these variations when deteninniBg the imwouiMt- tenter length.

|0173 In other embodiments, the control system. Ma tise various types of data, and various techniques, to determine when the payload 408 and/or payload coupling apparatus 412 have lowered, to he at or nea the ground. Further, the data, that is se : to determine when the payloa 408 is at or near the ground may be provided fey sensors on UAV 400, sensors on the payload coupling apparatus 41¾ and/or other data sources that provide data to die control system.

{M74J M sotne embodiments, the control system itself tnay fee situated on the payload coupling apparatus 413 and or on the UAV 400, for example, th payload coupling apparatus 412 rnay inetnde tagic; moduleCs hnpletaeaied via hardware, software, and/or fitniware that cause the UAV 400 to iunetioa as described herein, and the UAV 400 may include logic mod«le(s.) mat eonlmunieate with the payload coiipliu apparatiis 412 to cause tile UAV -400 to perform fuse tons described herein,

|θί 75f Figure 5A shows a erspective view of a payload delivery apparatus 500 including payload 310, according to an exam le embodiment. The payload delivery apparatus 500 is positioned within a fnselage of VAV (not shown) and includes a winch 514 powered by motor 512, and a tether 502 spooled onto winch 514. The tether 502 is attached to a. payload coupling apparatus 800 positioned within a payload coupling apparatus receptacle 51.6 positioned within the ruse!age of the UAV (not shown;}. A payload 10 is secured to the payload coupling apparatus O, in this embodiment a to portion 513 of payload 510 is secured within the fuselage of the UAV, A. lockin pin 5-70 is shown, extending through handle 511 attached to payload 310 to positively secure the payload beneath the UAV during high speed light,

{9176} figure SB Is a eross-seeti opal side view of payload delivery apparatus 50 and payload 510 shown in Figure 5A. In this view, the payload coupling apparatus is shown tightly positioned: wit th pay load coupling apparatus receptacle Si 6. Tenter 502 -extends ftxnn winch 51 a is attached to the lop of payload couplin apparatus 801 ⁾ , Top portion 513 of payload 510: is shown positioned within tie fuselage of the U AV .{hot shownl long with handle S3 1.

}0177| Figure 5C is a side view of payload: delivery apparatus 500 md payload 510

.shown in Figures 5A and SB, The top portion 513 of payload 5101s shown positioned within tte fuselage of the UAV. Winch. 514 has been used to wind in tetlier 502 to position the payload. coii hag: -apparatus within payload. coupling apparatus receptacle 516, Figures 5A.-C disclose payload 510 taking the shape of an aemdyuaruic hcxagotiaily^sfmped tote, where the base and side wails are six-sided hexagons and ilw tote Includes generally pointed ^' front and rear surface formed at the intersections of the side wails and tee of the tote providing an aerodyna ic shape.

VI» Example Capsnfes, Receptacle, and Package/Tote.

pl78| Fignre 6 A is a perspective view of payload coupling apparatus M, according to an example embodiment Payload eoupUug apparatus 800 iRekdes tether mounting pokf 802, and a slot 808 to position a handle of a payload handle in. Lower hp, or hook, Is positioned beneath slot 808:. Also include is an outer protfwsion 804 -hav ng helical cats stnr&ees :8.04a and S0 that are adapted to mate with corresponding cam mating surfaces within a pay load coupling apparatus receptacle positioned with a i seJage of a UAV, βί ? | Figure 68 is a side: view of payload eoupling apparatus 800 shown Figure 6A, Slot 808 is shown positioned above lower lip, or hook, 806, As shown lower lip or hook 806 has an outer snrfaee 806a that is undercut soch thai it does not extend as far outwardly as an outer stirface abo ve slot 805 so that the lower lip or hook 806 will not reengage with the handle of the payload after it has beers decoupled, or wilt not get engaged with power lines or tree branches during retrieval to the. U AV.

f O lSO J Figure 6C is a fr nt view of payload coupling apparatus §00: shown m Figures

-6A and 6B. Lower li or hook 806 is shows positioned beneath slot 81)8 that is adapted for seenring a handle of a payload.

JOiSl f Figure. 7 is a perspecti ve vie of payload eonphng apparatus 800 shown in

Fignres 6A-6C. prior to insertion into a payload coupling apparatus receptacle 516 positione in the fuselage 550 of a L AV. As noted previously payload eotipiiu apparar«s 800 includes slot 808 positioned ahove lower f tp or hook 806, adapted to receive a handle of a payload. The faselage: 550 of the payload delivery system 50CS ^; inehides a payload cou ling _, apparatas receptacle 516 positioned within the fuselage 550 of the UAV. The payloa coupling receptacle is prevented. This seerjatto results hi a prevention of the jamniin of the payioad coupling apparatus w&htn the receptacle.

1831 Figure 9 shows a perspective view of a recesses! restraifti slot arid payioad cooplmg apparatus receptacle positioned in a fuselag of a tJAV. In particular, pay load delivery system 3 !0 includes a fuselage 5 SO Jteyfo - .p& ioagl ^u !irig -apparatus .receptacl 516 therein that includes inward protrusion 530 having cammed surfaces 530a and: 530h that are adapted to mate with corresponding cammed surfaces on a. payioad couplin apparatus (riot shown). Also ir luded is a longitudinally extending recessed restrained slot 540 into which a top pQrt ijft of a payioad is adapted io e positioned and secured withni the fuselage 550.

|0iS4j Figure 10A shows a side view of a pay load delivery apparatus 500 with a handle: 511 -.of payioad _. 510 secured within a payioad coupling apparatus 800 as the pay load 510.moves downwardly prior to touching down for delivery. Prior to payioad touchdown, the ^' handle 51 1 of payioad 51 includes a hole 5 i.3 through which a, lower lip or hook of pay load coupling apparatus 80 extends. The handle sits within slot of the payioad coupling apparatus 800 that is sospended kom tether 502 of payioad delivery system 500 during descent of the payioad 51 to a landing site.

f θ ί 8S| Figure 1 6 shows a side vie of pay load del very a aratus 500 after payioad 510 has landed on the ground showing payioad coapiiug apparatiss 800 decoupled ttam handle 5 i 1 of payioad: 510. Once the payioad 510 touches the ground, the payioad coupling apparatus #00. continues to :move downwardly (as the winc .further unwinds) through inertia or gravity arid decouples the lower lip op hook 808 of the payioad. coupling apparatus 800 frorn handle 511 of payioad 510. The payioad: couplin apparatus 800 remains suspended, from tether 502, and can he winched back up to the payioad eoi¾pling receptacle of the UAY. | 186| Figure 1.0C shows a side view of payioad deliver apparatus 500 with payioad coupling apparatus 800 moving awa from handle 511. of payioad 510. Here the payioad coupling apparatus $ is completely separated from the hole 513 of handle 511 of payioad 510. Tether 502 may be used to w nch the payioad coupling apparatus back to the payioad eauplhig ipjparatus ^' ieeep&sie positioned in the fuselage of the UAV.

(0187} Figure 1 1 is a side view of handle 511 of payioad. 5.10. The handle 511 includes a hole 513 through which the lower li or hook of a payioad. coupling apparatus extends ihrongh to suspend the payioad. dnria delivery. The handle 1 1 includes a lower portion 15 that is secured _, to the top portion of a payioad. Also uieiuded are holes 51 and 16 through which locking pins positioned within the fuselage, of a UAV rosy extend to secure :the handle and payload a secure posit ion ring high speed forward "flight to a delivery loc tion. The handle ma be comprised of a thin, flexible plastic material that is flexible and provides snffieisafc strength- to suspend the payload beneat a U&V during forward flight to a deliver site, and: during deli er? and% retrieval of a payload, 1» practice, ike handle may be tot to position ie l¾mdie within slot of a payload coupling apparatus. The handle SI I also has sufficient strengihio withstand the toiqu© daring rotation of the payload coupling apparatus into the desired orientation iiurs: the payload eoa l apparatus receptacle, and rotation: of the top portion of the payload into position: with the reeessed restraint slot,

[θί | Figure 12 s ows a pair of locting pins- 57 _» 572 extending throngb- holes 5 ! 4 .and 51 in handle 511 of payload 510 to secure tile handle 51.1 and top portion of payload 510 wit in the fuselage of a HAY: IS this t a:-, the- handle 51 1 and payload 510 may be secured within the fuselage of a OAV, In this embodiment, the locking pins 570 and 572 have a conical shape so that they pull the package up- slightly or at least; remove any downward, slack present I». some embodiment the locking pins 570 and 572 may completely plug die botes 514 and 516 of the handle 511 of payload ^' .510, to provide a very secure attachment of the handle and top portion of the payload wstirm the fuselage of the DAY. Althoagb: preferah!y the loe ng pins are conical,, in other a lications they may have other geometries, such as a eyhndrica! geometry.

t i Figure 13 A is a perspective view of payload coupling apparatus 900 prior is having a handle of a payload- positioned within, slot 920 of payload coupling apparatus 900, Payload coupling apparatus 900 has a tether slot 90 on inner surface 904 of portion 914 into which a tether 02 is inserted. Also included is a pair of upwardly extending fingers 908 and 910 having a slot 91.2 positioned therebetween, A handle of a payload may be inserted Into the slot 9 0 of payload coupling apparatus 900 positioned between upwardly extending fingers 908 and 910 and inner surface 904,

101901 Figure B is a perspective view of payload coupling apparatns 900 alter delivering a payload -and decoupling Ac payload coupling apparatus 900 from a handle Of a: payload, In tbis embodiment,; the upper portion of portion.914 is weigh ted sueh that when the payload coupling apparatus 900 is decoupled: from the handle of the payload. the payload: -coupling apparatus 900 rotates 80: degrees s«eh that the fingers 908 and 10 are downwardly extending, thereby preventing the slot 920 from reenga ing with die handle of the payload, or engaging with t ee branches. or wires daring :retrie:val. to the mselage: of the U V. During rotation following decoupling, the tender 902 is pulled from the tether slot 906- (shown in Figure 13 A) and passes through slot 912 between fingers 90S and 910 -sae ^' that the pay load coupling apparatus 900 is suspended front tether 902,

jOiM ^' j Figures 14A-E provide various views of payload coupling apparatus 900 shown hi Figures 13A and. .13:8; As shown in Figures J 4A-E,. ike payload coupling apparatus 900 includes a slot 920 positioned between upwardly extending fingers 908 and 91 and inner ^■ .surface 904., A tether slot 906 is positioned in inner surface 904. A slot 912 also extends ^' between upwardly extending fingers 90S and 910. A tether attachment point 922 is positioned en a bottom of the payload co ling apparatus 900, The tether slot 906 extends from tethe attachment point 922 to the top of inner surface 904. Upper portion 91:4 of payload coupling apparatus 14 is weighted, such that upon payload landing, the payload coupling apparatus i autoniaticall decoupled front the handle of the payload, and the weighted upper portion 91 causes the payload coupling. apparatus 900 to rotate d wnwardl 180 degrees, Dunug this, period of rotation _. , a tether is pulled free from tether slot 906 and the payload. coupling apparatus is suspended from the UAV via the tether attached to tether attachment point 922 with, fingers 90S and 910 pointing downwardly. As a result, the fingers 90S and 910 are prevented ir ni s&gagiag the haadle of the payload when retrieved to the UAV, and: also prevented from engaging tree branches or power lines during retrieval to the UAV. Although not. shewn in Figures 14A-E, the payload coupling apparatus 900 could also include earnrued surfaces as showu in payload coupling apparatus 800 that engage with itratittg cams positioacd withlt a payload coupling apparatus receptacle in the fuselage of a ^" UAV to orient the payload coupling apparatus m a desired orientation within die payioad coupling apparatus receptacle,

ίθί:92| Payload coupling apparatus 900 also advantageously is a solid state design that includes no moving: parts, thereb reducing the complexity and cost of the payload coupling apparatus and eliminating moving parts that can possibly fail, A more reliable payload coupling apparatus is thereby provided,

10193 Figures 1 A-E pro vide various views o payload eoupbng apparatus 1000, In this embodiment, payload coupling apparatus 1000 has a generally spherical shape, A slot 1020 is positioned between outer Hp or hook 101.0 and: rounded portion 1014, The slot 1:020 is adapted to receive a handle of a payload, A tether attachment point 1022 is positioned on rounded portion 1:014. A. tether slot 1006 extends front tether attachment point 1022 to slot 1020 and is adapted to receive and: hold a tether. Rouiaied portion 101 or portion 1010 may be weighted suck that when 3 payload touches the ground, the handle of the payload. is deeou led from the slot of payload coupling apparatus 1000, During decoupling front the coupling apparatus from snagging during descent front or ictaeval to, t e fuselage of a UAV-

J0i9 I The present embodifficftfs provide a highly integrated winch-based pickup and dels very system for IJAYs, A number of significant advantages are provided. For exarrspie,. the ability to pick u aud deliver packages without . the seed for landing is provided, as the system is able to winch u a package with die aircraft hovering. Although in some locations, infrastructure s»ch as a platform or perch for tending, or loading the tlAV may be provided, in other location there may he no need for irsR-asfr«ei«re at the merchant or custodie location . The advantages include high mission flexibility and potentiall !Me or no infrastescfure installation costs, as well as incr ased flexibility in payload geometry.

Ι&20Ό1 hi addition, the payload delivery system may automatically align the top portion of the payload during winch up _s orienting it for nnnirnum. drag along the aircraft's longitudinal axis. This alignment enables high speed f rward fli t after pick up. The alipmerit is accomplished through the shape of the payload hook and receptacle. In the payload- eoupling apparatus 800, the lower Hp or hook 806 has cam features around its perimeter which always orient it in a defrued difeedon heii it engages into the cam features inside the receptacle of the fuselage of the UAV, The tips of the cam shapes on both sides of the capsule are asyratetric to prevent jatnroing m t e 90 degree orientation, 1B thi s regard, helical ca surfaces ma meet at a apex on o»e side of tire payload coupling mechanism, ^• arid uebcai cars surfaces may meet at a r unded apex on the other side of the payload coupling mechanism. The hoolc is specifically designed so that the: package hangs in the cemerltee of the hook _s enabling alignment in both directions fiom 90 degrees,

(02O1| -Payload couplin apparatuses 800, 806% 900, and 1000 include a hook formed about a slot such that hook also releases the payload passively and automatically when the payload touches the ground upon delivery. This is accomplished through the shape and angle of the hook slot and the corresponding handle on the payload. The book slides off the handle easily when the payload touches o n due to the mass of the capsule and also th inerti a ting to continue moving tire ca sule downwa d past the payload. The: end of die book is .designed to he recessed slightly from die body of the: capsule, whic prevents ifee hook, from accideutaily re-attachirsg to the handle. After successful, release, the hook gets winched hack ap Into the aircraft. Ail this taetionality (package alignment during pickup and passive release: during, delivery) Is achieved without any moving parts in this payload coupling apparatuses 800, 900,. and ii)0() (referred t as a solid state design.}... This greatly increases reliability and reduces cost Hie simple design also makes user i»i«arac io» y deaf and self-explanatory,

VH. eiher Cottiroi ariii Fayload FicikMp

}§202| A UAV may be able to pick it an deliver a payioad without landing. In som examples, the U A V Ma be able to raise attd lower a payioad coupled to a tedder by winding and unwinding the- tethe while hoveriag. As such _* lite UAV -may pick up and deliver the payioad. without requiring infrastructure io be set up by a merchant or customer, thereby increasing a flexibility of dsilvery location and/or payioad geometry aud decreasing or eiiminaiing costs associated with the roanuisctMre or installation of iafrasirnciure. In oi er ex mples, the .OA ¥ may be eont1:g ired to tend on vatiows elevated stfisciBws, such as a perch or shelf, and, from its elevated landing, position _. pick tip or deliver die payioad by winding or unwinding the tether,

f¾283| Figure 17 sho ws a method ϊ 700 for tethered pickup of a payioad (e.g., a. package} for subsequent delivery to a target iocatioa. Method 1700 ma be carried out by a. FAV Such as those described elsewhere herein. For example, method 1.70ft may be carried out by a eoutro! system of a UAV with a winch system. Further, the winch system may include a tether disposed on a. spool, a motor operable in a -first mode and a second: mode that respectively eouOier and assist unwtedirig of the tether due to gravity (e,g„ by driving the spool forward or St reversej _>; a, payioad coupling; apparatus that mechanically cowpies the tether to a payioad, and a payioad latch switehable between a closed position that prevents the payioad from being lowered from the U and an open position that allows the payioad to be lowered from the UAV,

|Θ2Θ4| As shown by block 1702 of method: 1700, when the UAV arrives at a pickup location (also referred to as a source locarioa), the DAV¾ control system may opea tire payioad latch, such that the tether and. the payioad eorspling apparatus can be lowered ^' toward the ground at the pickup Ideation,

jQ2 | At block 1704, tire control system operates the motor to rwi a predetermined length of the tether. This unwound length may correspond to an expected payioad attaelrnerst altitude for the payioa coupling apparatus;, which is attached to the lower end of the tether. The payioad attachment altitude may be an altitude at which: a human, or perhaps a robotic device, aiay grab the payioad coupling apparatus for attacMn the coupling apparatus to a payioad. For fastariee, the payioad ^' attachment altitude may be an altitude less than two meters above ground level. Qfher examples are possible as well.. [020$! After .un inding the predetermined length of the tether, the control system:

■may wait to a predetermined payload at aeteeftt period, as shown: ^' by ^' block 1706,. This attachment period allows time for a human, or perhaps a ro otic device, to attach, a payload (e.g., & ackage for delivery) to the payload coupling a paratus. ^' The predetermiued payload attachfflest period may e a feed value or ma vary ¹ based OB aa operational stale of the OAV,

} ^' 020?| When the payload tt chment period ends, the control system may operate die winch motor in the second mode for a predetermined attachment veri&atiQn period, as shown by block ;l¾ particular, the motor may operate so as to pull upwards on the tether dining the attaebs«e¾t verification period m orde to bold the tether m place or retract the tether at a certain rate. The motor errrrent required to hold die tether iu place or retract the tether at a certain rate wdl. be greater when, th payload is attached, due to the added weight of the payload. As such, the control system may determine, based, at least is part on motor current during the predetenniued 'attachment verification period, whether or not the payload coupling apparatus is nieehatucally coupled to the payload, as show* by block 17 I ⁾ .

[02081 In practice, for instance, if the raster current is less than an attaehinetrt threshold current, the control system may .determine that, the payload has no bees attached : the payload coupling apparatus, and may repeat the process of lowering the payload. {this time by some predetermined dditional length), waitin for a predetermined- payload atfaehmerji period, and then pulling upwards: -on the tether to test for. payload attachment, shown i« blocks 1704 to 1710. On the other hand, if the motor current is greater than or equal, to the atiaehraerrt threshold enrrent, and bloefc 171(1 results a determination that the payload. coupling apparariis is mechanically coupled, to the payload, the control system may operate the wiach motor to retract the tether and lift (he attached payload towards t e U ^' AV, as shown- y ^' block ϊ~?12.

f$209| The control system ma cooiimie retracting the tether until it senses that the payload .coupling p aratus: is at or near the OAV, at whic point it initiates■actions to secure the payload for flight to the target location. For instance, method 1.7 ¾ includes functions that niay be used to secure a package and a coupling apparatus in. a receptacle of a IJAV, such, as in the eoni¾«ratio.as shown in Figures SA-5C.

{021Q| More specifically., at block 171.4, the control system ma determine that both: t .,s the unwound length of tether is less titan a..threshold length and (b) the motor ctttteirt is greater than a threshold current When both these conditions hold true, this may serve as an indication that the payload coupling apparatus and or the payload have reached t¾e UAV receptacle, fn particular, when the calculated mrvon length of tether is at or near xc.ro, this may radicate that the payload coiip flg apparatus aj or the pay load Slave bees lifted: all .the way to the V Further, when i e payload eetspling apparatus and/or the payload contact the UAV's receptacle area, the motor current may increase as the motor's speed controller attempts to continue pulling the payload upward. And, by considering both these indications, the control system may avoid false positives.

0 JjJ I has, upon■detecting both of the above-described indications, the control system may respousively operate the motor is the first mode to p«H the ^■■ .payload. into _s and orient the payload within, &e receptacle oft the fewer surface of the UAV ^' , as sho n by block 1716. in pathenlar, the control system may operate me motor to increase the tort e applied to the tether, such as by increasing the eurrci t supplied to the motor to a predetermined, value, in order to help ensure that the payload coupling apparatus (and perhaps the payload as well) are firmly seated a ainst the cofrespo« Ktig surfaces: of the UAV's receptacle, such that the payload. la ch (e.g„ pins 579 and 573 of Figure 12) c be closed to secure the payload for flight to the target location:. Accordingly, after applying torque to the tethe in. an. upwar direction tor a predetermined period of time, the control system ma close the payload latch, as shown by Mock i 7 IB. With the payload secured ^' for flight, the ^' UAV may navigate io a target location for d ivery.

VOL Tether Control Durin Fayload Delivery

&212I Once the iJAV arrives at the target location for deh ^' very, the UAV's control system may respomively operate in a deliver mode. Figure 1.8 is a flo chart illustrating method. 1800 for operation of a IJAV in a delivery mode, according to an. e¾arrjpte embodiment,

|0213| Mote specifically, once the UAV arrives at and is hovering over a target location for tethered delivery, the UAV's control system, ma operate the motor to tr vred the tether accordin t a predetermined descent profile, as shown by block 1802. The predetermined descent profile may control descent rate of the payload by specifying a desired rotational speed of the motor.. .For example, the descent profile ma specify' a: constant descent rate or a vari able descent rate for the duration of the payload descent.

|0214J In some examples, the desired rotational motor speeds specified by the predeiermine l descent proilfe could be based on machine-learned data mat could be inferred from data from prior Sights. Fo example, for delivery to a particular location, the control system could rise- a descent profile that was previously psed during a previous delivery to the particular location, Aheraatively, if use of the descent profile during a previous deli very to that particular location of some ^■ ■ other location resulted ¾* one or m te detected errors (e.g _v , failure to detach, the payfoad from me tether, damaged pay ad, etc,), then the control system coul alter the descent profile ie,g, _: , by Incr asiBg or decreasing the desired motor speeds during various phases of the payload. descent) or choose to ose a default deseent profile instead.

pilSf in an. example method, fee control system may no exert significant control over :t!ie descent of the payloa until, it is closer to the groantL For instance, at some point while die tether i$ unwinding, the■control, system may determine that the ag ound length of u*e tether is greater than a threshold length, and resjsonsively operate in. a pre-touchdow raode, as shown by block 1804. The threshold, length may correspo d^ to a ^dctexrttined near-groitnd altitude of the payload; eg., a height where more control, is desirable for the safety of bystanders and/or ground stractnres, and dr to protect tile payload and its contents from, damage,

ΙΘ2Ϊ&1 As te j in the pre^tonehdow mode, the control system may pay etese attention to the pay load to improve the chances of successful release of the payload on the gronnd. la particular, while operating in the pre-tottehdo n mode, the control system operates iiie motor such that the tether continues to unwind accordin to the predetcr irsed descent profile, as shown by block 1.804a, while monitoring both, rootor current and motor speed, as shows by block 1804b. T e motor current may be compared to a predetermined payload-uncoitplhig ewrreiit to: detect when the motor correal is less than the predetermined payioad-itriconpltn current. Additionally _^ the motor speed may be Compared to a predetermined payl.oad-uneoiipMn speed to detect when the motor speed is less than the predetermined payload«-uncot5plipg speed, as shown by block 1804c. When both the motor current is less than a predetermined payload-uneouplmg eiareni and the motor speed is less than predeieraiined pa>da%d~irncoirpl.ing speed, the control system, responsiyely switches to operation in a possible-touehdowii mode.

f Q2I7J The posslhie»ionchdown mode may be implemented in an eil rt to verity that the package has-, fact, reaehe the ground (or put another way, to help prevent false positive detecti on of contact with, the groand). For instance, while operating i the possible- touchdown mode, the control system may analyze the motor earrent to verify that the motor current remains below the predetermined payiQad-unconpiin current for a. iouehdowri- verification period. (e,g., perhaps allowing for a small amount of fluctuation dtrring this period),: as s own by bioclf 1806, in practice, a Sehniiti trigger may be applied to verify dial the detected drop in motor earrent to below the payload-unconpling threshold is not ite result of noise or some temporary blockage, and is in fact due to die payload. resting an the ground. Other teehmques M veritying touchdown of the payload are -also possible.

j02l8| Once touchdown of ike payload is verified:, the control ^■ ■system operates the motor §«c¾t that o er-ras of the tether wd payload coupling apparatus occurs, as sho by block 1808. Qvet-r r oeews when the payload comes to a fist while the tethe continues to unwind. In practice, for example, ihe control system- may switch the winch motor om me first mo e to the second mode fey, e,g. _s ie -ersig me direction the motor and thus die directors, o torque applied to me tether by the ^' otor.. Thus, the motor may switch from slowing the descent of the tetter to forcing the tether to nwind such that over-run of: the tether occurs, ihe over-run- of the tether am in torn lower die payload coupling apparatus below a height where couplijig to tile payload occurs (sad perhaps all the way to the groitud), la other embodiments, block 1.808 may Involve- the control system simply turning the motor off, sad allowing gravity to pull the payload coupling apparatus down and cause the tether over-run.

[ ϊ¾ Further, as shown m Figures 6A-6(L 1QA-1 G. and I K the payload and or payload coupling apparatus ma Have interlacing surfaces such that the Interaction, of t ie payload and payload coupling apparatus- durin over-run deflects the payload. coupling apparatus to the side of the payload. As sacti _* the coupling feature of the payload coupling apparatus a hook) will no longer fee aligned with a corresponding coupling feature of the payload (e.g.,, a handle on a tote package). Located as such, the winch system ra y retrac the tether and payioad coupling apparatus to the UAV without the payload eoupliug appafatos re-coupling to the payload, thereby leaving the package oft the ground.

|022$| In some examples of method 1800, the control system may he configured to, prior to opening the payload larch, operating the motor to apply an upward ibree on the tether. This may allow for the payload latch to he opened more easily, as the payload may he arranged to rest some o all of its weight oft. the payload latch hesi the latch is in the closed position. The weight of the pay load may increase the riction against ihe payload latch when attempting to switch the latch to the open position, so lifting the payload a predetermined amount may reduce ccu rences of the payload latch getting stack lit the closed position Additionally, after opening the payload latch and before, unwinding the tether, the control system, may fee configured to operate die motor to .hold the tether is a substantially constant position. This may allow the weight of the payload to pull the pay load downward and against the pa lo coupling a aratus:, causing the payload to become firmly seated p a coupling mechanism. (e.g., a hook) of the payload coupling apparatus. ^• fiie motor thai is indicative of the intentional :user-i«teraction -iih "the tether, the conttoL systera niay determine a motor response process, as shown by block ίν-θδ of metho 1900; And as shown by block I¾S of method ^" ! . 1K) _} tise control system may then operate the motor in accordance with the .deiermiried moto r sponse process.

i, D& rmimng Qp&ratktmi Pe ameie motor

|0225f As noted above, iiie UAVs control system ma determine one or more operational ^■ ■parameters of the motor. In practice, m operational paraitieter of the motor may be an measure of the motor's activity,. Although certain operational parameters are described herein,, other operational parameters are als possible without departing from, the sc ope of the s¾seat disclosure,

(8 ^· 22έ| y way of example^ aft operational parameter of ilie motor may be current characteristics of the motor, such as a current level being provided to asd br generated b tie ■motor over time or at a particular instance in time, among other possibilities. In another example _* a operational parameter of the motor may be speed characteristics of the mote;, sneh. as a speed, of rotation, of the motor's tra smission assembly over time or at a articular Instance itr time, among other possibilities. In yet another example,, an operational parameter of me motor may be rotation characteristics of the Motor, such as as extent of ^' rotation of the motor's transmission assembly over time, among other possibilities. Other ^' .exam les are possible as well

{ 2 1 Generally, the .control system may determine one or more operational parameters of the. motor in various ways, For instance, the control system miiy receive* from: ^■ one- or more sensors coupled to motor,, -sensor data indicative of operational parameters. Once the control system receives the sensor data, the control system may then use the sensor data to determine a«d/or evaluate the operational parameters of the motor..

|022f| By way of exa ple* a current sensor may be coupled, to the motor and corifi&ored t senerate current data indicative of a current level being provided to and or ne ate by" the motor. With this arrangement, the control sy stem may receive current dat irosA the current sensor and may tise the received current data as basis to determine■eunrent characteristics of the motor. For instance, the control system may use the received current data as basis to determine particular current level of the motor over a particular time period. {QZ29$ In anothe example, a speed: sensor may be coupled to the motor and ^■ configured to generate speed data indicative of speed of rotation of the motor 's transmission assembly. With this arrangement, the control syste may receive speed data flora the. speed sensor and may use the received current data as basis to deierarine speed characteristics of the motor. For instance, ine control- system may use the received speed data as bask to determine a pasiieular: speed of the. motor at a partiettla ^■ point in time.

.[0230] lh yet another example _* m encoder siay be coupied to the motor's transmission assembly and confrgnred to generate position data representative of the transmission assembly's over time. With this arrangement, the control system may receive position data from the encoder and may use die received position data as basis to determine rotation: characteristics of ike motor. For instance, the control system may use the received ^■ position data as basis to determine an extent arsd/or a direction of the transmission, assembly's rotation taii a first point in time to a second poirit in time. Other examples and instances are possi le s well,

(023.( Figure 20 next shows a graph illustrative of example ettrrent characteristics

2000 of the niotor. A shown, die current characteristics 2000 represent i!ie motor's current level over nwe. In practice,, the current level may change over time based on various factors. For instance, the -current level may change based -6a torq«e/fdrce that the motor seeks to provide (e.g _<5 to the tether) and/or Based on an . -external, torqite foree provided to the motor (e.g., via the temer), among other possibilities. Other exarapks are possible as well.

ii. Defecting an Operational Pattern afiha eter thai is Indicative ^' &f & User-Jnteraetkm [-0232] As noted above, die control system x detect, in the one or more operational paranieters, an operational pattern of the motor that is indicative of an intentional aser* interaction with the: tether. In practice, an operational pattern may be air contiguous- and/or noncontiguous sequence of values o One or more operational a amete s over time. Moreover, die control syste may use any currently known and/or future developed signal processing techniques or die like to detect an operational pattern. Nonetheless, an operational pattern could: take various forms,

[02331 in one ease, an operational partem, may be a pattern found i» a single operational- parameter. For instance, an operational pattern ma be a particular pattern of current characteristics, such as a particular sequence of current levels being represented by current data over time. In another ease, however, an operational pattern may involve patterns respectively found in two or more operational parameters over die same time period and/or over different respective time periods. For instance, an operational pattern may be a particular pattern of eu re-nt eharacterlsties over a first time period as well as- a particular ^■ pattern- of speed characteristics o ver a secon time period (e.g., same as or different from the first time period) .. Other eases are possible.8$ well j0234| Given the above-deserihed am»igetnent, the control system detecting as operational pattern may involve t fee control system d tectin varioas patterns among one or tMore determined parameters. By way of example (and withottt limitation), the : ^■ control system detecting aft operational pattern may involve the control system detecting any combination of the .following: a particular relative change of motor entrant, a particular fate ■of change of motor current, a particular motor em-rent value, a _. particular sequeace of motor current hies, a partienlar relative change of motor speed, a particular rate of change of motor speed, a pariicalar mo-tor speed vahte, a particiikr seq«ence of motor speed values, a particular relative eliange of motor rotation, a pairtienlar rate of change of moto† rotation, a particular tnotor rotation value, and/or a particular secaience: of motor rotation: values, among others.

}023S| 1» accordance wit the present diselostire, as noted, detecting an operational partem may specifically involve detecting operational pattern of the motor that is indicative of an intentional Hser-mteraciion with the tether. More specifically, when a user interacts with the tether in a particular manner, the motor may exhibit a particular operational pattern. As such, established operan ^' onat patterns (e.g., established vi manual engineering Input) that the control system can detect may each correspond, to a respective user-inier action with the tether. In this way, when the control: system detects a. pariicolar operational pattern _* the control system, ma effectively detect a particular user*inte'aetiott with the tether; in practice, the control system may do so simply detecting the operational pattern and without there necessarily feeing a logical indication Of a iiser-mteraction,

|0236J 1B some eases, o ever, the control system may maintain or ma otherwise refer to mapping data that maps each of a plurality of operational patterns of the motor each with a respective user-mteraciion. For example, the mapping data may map a particular cartent level pattern with an indication of a user providing a particular downward force on the tether, hi practice, the particular downward force may he a force that is applied in a dimciion sabstantialiy perpendicular to a ground surface and/or ma he a force that Is applied in a direction that is at anothe angle (e.g., 45 degrees) relative to the ron^d srtrfece (e.g., such as when a aser catches an. oscillating tether and then tugs on it at an angle), in another example, the mapping data ma map a particular speed level patters: with an indication of a user moving the tether side to side at a particular rate, in practice, soeh indications conld eac take on any feasible forms, such as the form of letters, nnnibers, and/or logical Boolean valaes, among others. Accordingly, when the eoritroi system detects a pariictiar operational ^• pattern, the contr l system ass refer to the mapping d.ata to determine the user-interaction that is respectively mapped to that particular o ©rational pattern

,[023T{ ^· Moreover, different operational patterns ma mstimss bo indicative of the same user-interaetoit For this reason, the control system ma be arranged to detect a first operational pattern arid fhtts effectively detect a particular useF-interactjoa with the tether, and ma also be arranged to detect a second operational at ern and thus effectively detect the same particular user-interaeiion with the tether, such as for purposes of determining a motor response process as further described below. Alternatively, two or more operational patterns in the mapping date could each be mapped to the same ^" nser-iMeraetio¾ s feat the control system detects the -same n$er½ter8Ction. when tefem&g- t either one of those operational patterns in tire mapping data. Other eases are possible as well

|0238 Yet further, when various detectable operational patterns are stablis ed at least some of those established patterns could account for various external forces that may be applied to the tether, sitch as external forces other than just those being applied by a user during an. interaction with the tether, hi particular, the operational patterns may account for gravity, external forces based ^' &β. weight of the payioa coupluyj appatatos, and/or external forces based on weigh of a upled psyload (e.g., a weight of a package to be shipped), amot% others. In this way _* the control, system :«iay fee able to detect m operational pattern, of the motor that is exhibited when such external forces are a plied to comhi tion wife; external forces that are based on a aser-feteraetiou. Other extertral forces are possible as well.

($139f In ye a further aspect in addition to o instead of the above-mentioned. mapping data, the control system may use one or more oilier approaches to determine a user interaction based on art operational pattern of the motor..

(0240] 1B one ease, the control system may carry ont signal processing and/or analysis techniques to determine lueCs) and/or irendis) of a signal (e,g,, a signal representative of moto speed values) and to determine the user-interaction based on those vahte{%) and/or trendfs) of the signal For instance, the ^■ . control system: may evaluate a set of -conditions of a signal so as to determine whether or not all conditions within the set are defemrined to be true. If the control system determines that ail conditions of the set are true, the control system may determine that the signal corresponds to a particular nscr-interaction. Otherwise, the control systeni may e vahmte another set of conditions so as to determine whether or not alt co di ions within that other set are determined to be trae, and so on, in an example of this approach, the control system may determine; whether or .trot a slope of the signal is within, a particular range of slopes arid ma determine whether or not a value of the signal exceeds a particular tihresno value within, a pa:frieular t fesh© extent of time. And the control .system tsay determine thai the signal .eowesponds to a particular user-interaction if the control system: etermines both of these conditiosis to be true. Oilier examples are also p rn te.

f0241| In another case, die control system may carry out probability analysis techniques to determine die .user n^¾ction, For maniple, the control syste may determine that a detected operational pattern does not precisel match one of the operatiosaS patterns of the mapping data and thus wa apply probability analysis to deteranne the operational pattern of the mapping dat to which ti detected operat onal patten* matche wit the highest likelihood. For nstance, w ti .determining tie match, the control system .may give a ¾igfeer weight to a certain portion, of the detested signal/pattern compared to ilie weight given to other portions of the detected signal/pattern, thereby applying an additional factor to determine the matching operational pattern and thus to yltimately the ¾ser*intef action based ^• on iiie mapping data. Other cases an examples are pos ible as well,

f 0242 J Figure 21 nest illustrates a example operational, pattern of the motor tJ ai is indicative of a particular user-lntef action widi tiic tedier. As shown, die control system may detect a particular current, spike 2002 in the above-described current characteristics 2000. To do so, the control ^' wstera may detect a - particular increase- in current level over tim® followe by a. particular decrease in current ^' level' over time. Additionally or alternatively, the control system may d so by detectin a particular rate of increase is current level over lime followe by a particular rate of decrease of current level over time. In either ease, the particular current: spike 2002 is show as: being Indicative of a particular user-iuteraction 2110 involving a particular downward force bein applied to a tether 2102.

(Θ2431 More specifically. Fi ure 21 shows a DAY 2100 that Includes winch system .2106 with a motor configured to control movement of the tether 2102, As shown, a user 108 physically interacts with a payload coupling apparatus 21 -04 that is coupled to die tether 102, In doin so, die user 2 ί 08 applied a downward force to the tether 102 via die payio&d, couplin apparatus 2l 4 _r the downward force havin a. magnitude of 'ΊΡΡ ^' ·.. As such, the particular current spike 2002 is Indicative of a user applying to a tether a downward, force havin a magnitude of 'Ψ Other examples are possible as well.

til Determining- a otor M.esp®ns£ Process

f(l24 | As noted above, the .control system may determine a motor response process anti do s based o tile detected operational pattern of tlie motor that is indicative of the Intentional aser-interaedon with die tedier. In practice, a particular motor response process and/or tre»d(s of the signal For instance, ib& control system may evaluate a. set of conditions of a signal .so- as to deterixine. whether or not all conditions within the set are determined to- be true. If tke control system determines -that a l conditions of the set are true, the control syste may determine that the signal corresponds to a particular motor response process. Otherwise, ike control system may ^' evaluate anoth set of conditions so as to determine whether or not alt conditions within that other set. are determined to be true, and. so OB. In an example of ^' this approach, tke control syste may detemhne whether or not the signal includes an mfleetion point and may determine ^nether or not. a value of -a local maxima of the signal exceeds a partieuiar threshold value. And the- control, system may deierhline {feat the signal corresponds to a particular tii tor tesp rise proeess if the control system determines both of these conditions to he true. Other examples are also possible, f 0:250 J hi another ease, the control system, may cany oat proba ility analysis techniques to determine the motor respo se process. For example, the control system may determine that a detected operational pattern does not precisely match one of the operational patterns of the mapping data and thus ma apply probability analysis to determine the operational pattern of ine iiiapping data t which the detected operational pattern matches with the highest likelihood For instauee, when determining the match, the control system may determine a state of the environment i/w of ^' the UAV during which the operational pattern is detected, an ma use the state of the. environment and/o of the UAV as as additional weighte facto for detemiiuing the matching operational pattern. In this way,, once the control system determines the matching perational pattern rising the the probabilit analysis,, the eontrol system may then determine the motor response proces based on the mapping data. Other cases and exa ples are also possible.

(0253 In a system arranged as described above, the motor response process may Involve arious motor response operations, some of which are described below.. I practice, the control system may determine the motor response process to include a single such motor response operation or an feasible combination of these moto response Operations, ■.Assuming; two- or more motor response operations are: detennined to he carried owt, determinirifi the motor response process ay also involve determinin an order for carrying out motor response operations (e,g. _s with some motor response operatiorss possibly feeing _, repeated at various points fhroughotit the order) and/or a respective dnraiion for applyin each motor response operation, among other possibilities. Generally, stseh an order and/or ^• durations may be determined based, on various factors, such as based o the detected operational pattern of the motor for instance. Alter¾&tivoiy _s such an order and or dnrations may be- sdfetetemed in accordance with established mapping data,

j0252| & either case, ^' Various possible motor response^ operati n are: described below. Although certain motor response operations arc descr bed,, otter Motor response operations are possible as well without departing from the scope of die present disclosure.

|0253f in one example, a motor response operation may involve a particular eotmtering operation that counters, unwindin of the terhef dae to at least one external force applied to the tether. As part of such aa operates, the eoatrol system may operate the motor to apply one ox more: particular couriieracdrjg t ues that each coniiferaet uirwindiitg of the tether, and possibly $ fc each cto atersetrng. t$sx$ a respective dum oh. Specifically, each neh counteracting torque may be at a magnitude that is subsianiially the same as the external fbrce{s3 being applied and may he a direction ihat. is efiectivelv opposite to direction la which external ihree(s) arc applied. In this wa , (his response operation may resist amen ing of the tether dye to the external fbree(s) being applied without necessarily ^• causing retraction of tbe tether back t the tJAY<. In practice, a nser applying an external face to the tether ma essentially feel that tbe tether cannot be lowered any farther. Moreover, as magnitude of such counteracting torqites increases, the tension of the tether may mcTease as well.

f 02541 I» another e rnpie., a motor response operatio may involve av partieotat assistance operation that assists iniwinding of the tether due to at least one external force applied to the tether. As part Of such aa operation _^ the eoatrol system may operate the motor to appl one or more particular 'assistive- torques that each assist unwinding of the tether, and possibl apply each assistive torqu tor a .respective dotation. Specifically, each such assistive torque may be in a direction thai is: effectively that same to: direction in which external fbrce(s) are applied, and may he of any feasible magnitude. In ibis way, the assistive torques raay be used in combination with the exterttal force(s) being applied so as to further help unwinding of the tether, in practice, a user applying mi external force t the tether may essentiall feel that maausl im mdiug of the tether has been made easier due to iesse resistance to the unwinding.

(0255J la yet another example, a motor response operation may involv a particular retracting operation that retracts ihe tether against at least one external force applied to the tether. As part of sush an operation, the eoatrol system may operate the motor to apply one or more particula retracting to ues that each retract the tether agaiast the exterriai forceCs), and possibl apply each retracting torque for a respective duration. Specifically, each such retracting tmq may be at a magnitude that is larger than the e ternal ibree(s) being applied and may be in a direction that is effectively opposite to direction winch external forceCs) are allied: In th s way, this ·. response operation may resist nmvindin of the tether: dm to the externa! l¾rce(s) being applied and in fact cause retraction of the tether back to the UAY despit the external ioree(s). In practice,- a user a l ing aft external force to the tetter may essentially fed that the tether is palling against the user to an. extent that the tether retracts even as though, the : oser applies t external force.

J02S6J In yet anot er example, a motor response operation may occnr after application of an external bree by a user ralher than, du ing application of an. externa!, force by a user.. For instance,, a raotor response operation ma involve a tether movement operation that moves the tether In accordance with a particular tether movement profile after the external force is applied onto the tether. In practice, such a moto response operatio may allow for user teedback/interaetsoti to be carried out even w e a user no longer physically interacts with the tether.

|02S?| in this rega d _s the control system con i d detect an ope atiosal pattern indicative of a particular esex interaction ^' and then determine a motor response process that is to be ear ied out after the pariienlar user interaction- is complete., in particnlar, the control system tnay determine that the particular user interaction is complete ¾y detecting yet another operational pattern of the motor that indicates so and/or may do this its oilier ways. In either -case _* once the control system determines that the .particular user interaction is complete,: t e .control system could then carry out the determined motor -response process that involves mo vement of the tether i accordance with a particular tether movement profile.

[025BJ Generally, the- particular tethe movement profile may take various forms and ma be based on the operational pattern indicative of the nser-interaetion. For instance, the tether movement profile .may simply involve retraction- of the tether baek to tire UAV" at a particular rate. In this instance, movement of the tether in. accordance with this tether mo vement profile ma occur based on detectin an operational pattern that Is indicative of the user pulling down on th tetlrer several censeeistfw times. Other instances and examples are possible as well.

(Θ2591 Figure 22 next illustrates an example motor response, process. As shown, the control system determines that the above-described particula user-interaction 21 1 corresponds to a moto response process 2200, Specifically , the -motor response process 2200 involves a countering operation that cludes application of a counte in ton e. Th t countering tOKfue ma have a magnitude of ^, that is substantially the same as the magnitude "F I " of the downward force feeing applied ^' by the user 2108. Also, that countering towpe may he in a direction that is effectively opposite to the dkectio of the dovBiwa d force- feeing applied b the Bset 210$. As si!eh, the control system may ultimately operate the ^■ motor of fee winch system 2106 to appl that countering torque as the m& 2108 applies the downward force onto the tether. Other examples are also possible.

Operating the- Motor in Accordance wit the elerminoi Motor Response

Process

|Θ26Θ| As noted above^ once a motor response process i determined the control system may t en operate the motor in: isccordalice with the determined motor response process, speeiSeslly doing so by transmitting to the motor one or more commands that instruct, the motor io carry out certain operations in line wife the response process. And as further noted, above, .fee control system y do so during and/or alter a user-interaction,, ■depending o the motor response process that has been determined. Moreover, the motor response process thai is carried out ma lead to various outcomes hi addition to the planned iiiteraetion/ftedteaek with the user.

For example, fee motor response process ma correspond to one or more target tension forces being encountered by the tether. Specifically, each target tension force t»ay be One that is expected to fee experienced: by the tether when the motor applies a certain torque in accordance with the motor response process. As such, the control system o erating the motor in accordance with the determined response process may cause one or more such target tension forces to be encountered by the tether

|Θ 2| In -another example, the motor response process may correspond to one or more target tether movement being encountered, by the tether. Specifically, each target tether movement may be ne that is expected t be experienced by the- tether when the motor applies a certain, torque in accordance with the motor response process. As siich, the control System operating the motor in. accordance with the determined response process ma canse one or more such target tethec- movements to be eneoButered by the tether (e.g., a wave pulse traveling through the tetherh Other examples see also possible.

J02631 Figure 23 next ithisitates an exattspie motor response p ocess in. which the control system operates the motor to control, tension of the tether 2102 as the user 2108 grasps onto the tether 21 2, sneh as daring the process of mannali coupling a payfead -for instance, Assumfeg that fee D Y 2i00 substanttaii maintains its physical position space while havering, the control system may pr poriionaMy t¾ ^: .g., linearly) insrease the torque of fee motor In a w nding direction as a downward force provided by fee user 2108 increases, an Vice versa. la this way, the tettsioft of the tether 2102 may increase as the user 2! S pnl!s the ¾her 210 furifcer down, and vice versa. Moreover, the control system iaay be configured proportionally Increase the torque of the motor tip to a maslmym tonpe, thereby s teaiin the: tension of ike tether and ideally preventin the user 210:8 iron) pulling the UAV 2100 do a towards the ground.

|0264| More specifically, at state 2302 of the motor response process, the control system operates tfie motor to apply a torque having a magnitude ^* Γ ^ί: to counteract the magnitude "F Γ" of ^' the force provided by the wser 2 08, thereby resulting, ie first tession force Being encountered hy the tether 2102. Tine , at state 2304 of the motor response process, the- control system Operates the motor to appl a ^■ t0rque.. viag a ^¾¾iiiude ^'i< J2 ^M' tha is larger than ^' "Ti ^": and do so to counteract the force magnitnde "F2" that is larger than "Ft", thereby resulting iu the tether 2102 encountering a second tension force t t is large than the first tension force. Finally, at state 23 6· of the motor response process, the control system operates the motor to apply a to«pe having a magnitude "W that: is yet larger than "T2" and do so to counteract the force magnitude "F3 ⁵⁵ that is yet larger than ^S 'F2 ^!5 , thereby resulting in the tether 2102 encountering a third tension force that is yet larger than the second tension ibree.

j&2-65 Figure ^' 24 next illustrates an example moto response process in which the control s stem may operate the motor to vary the amount _* aad possihly the direction, of the torque that is applied to the tether 210 over time _* specifically doing: so to enhance nser- experienee or tor other reas ns. For instance, the control system may operate the motor to replicate the feel of detents or clicks as the user 2108 palls down on the tether 21.02, -and/or to provide vibratioaal feedback (e.g., a wave pulse) via the tether 2102, among other possibilities.

| 266| More specifically _* at state 3402 of the motor response process, the control system operates the motor io apply an assistive forqae thai ha a magnitade "Ti" and is in the same direction as the force provided b the user 2108, merefcy assisting the user 2108 with unwindin of the tether 2102, Then, durin amvinding of ^" the tether 2102 at state 2404 of the motor response process, the control system operates the motor to apply a counteracting _: torqtte having a magnitude ^* 'T2" to counterac the ma nitude "F2" of the force provided by the user 2108, fcereby resulting in a feel of a "detent' ^■ being experienced, by the user 2108, Finally, at state 2406 of the motor response process, the control system again operates the motor to: apply an assistive torque, so as to eontaue assisting the use 2108 with unwinding of the tether 2102. Specifically, this further assistive force is shown as having a magnitude "T3"

the like listing fee various gestures that are interpreiable by the disclosed system.

|02fi$f More specifically,; as sfewj by state 2504 of the motor response process, the control system responds to the gestitre by carrying out a motor response process that involves operatin the motor to apply torque having a magmtude "T2" lor purposes of retracting the tether 102 ^' back, to the UAV 21(10, Moreover, the control system does so ortee the user 2108 has completed interaction with the: tether 2102 and thus no longer applies external forceCs) to the tether 102. Finally, once the tether 210 has been retracted, the H Y 2100 ma then proceed with forward flight to a target; destination, as shown b state 2506. Other examples are possible as well,

v. Additiami Features of !Jser Interaction and Feedback

10269] Irs a ftirther aspect, the control system could consider othe factors as basis fo determining a motor response process., in practice, the control system may consider such factors, in addition t or instead of consideration of the detected operations! pattern of the motor as described above. Moreover, the control system ma coHSider art feasible combination of these factors, possibly giving some factors mote weight compared to others.

In one ease, the control system may consider a state of the environment as basis for determining a motor response process. Specifically, the control system may receive, from one or more of the IJAV' sensors (e.g., image ca nsre device)., sensor data representative of the UAV's- state of fee environment, such, as of obstacles near the U , among other possibilities. And the control s em ma then determine the motor response process based at least on that sensor data. For example, if the control system de ects an. obstacle within a threshold distance away from the tether, the control system may

the payload coupl ng apparatus) and the conttol sensor iaay receive, ftom the altltade sensor, altitude data indicative of the payload altitude, in another example, the control system ma deiermirie an unwound length of the tether, such, as b using, techniques described herein, for iasiaoee. Also, the control system may deteraitae a Sight altitiide based on altitude data received from an altitude, sensor of the UAV, among other possibilities, ^' t en, the control system may use tile determined tmwound tether length of the tether as well as the detenrsined flight altitude as basis for determining the payload altitude., for example, the control system, m subtract the determined anwoniid tethe length of the tether (e,g. _s 5 feet) ft rn the determined flight altitude (e.g>, l i ieet above grotind so as to determine the payload aiiitude (e.g., f> fee above gjOun.d). Moreover, the control System may take various p roach s for determining that the p& &d altitude is o«e at which a user»lntetaetion is expected. For ifistatice, the control system may determine that the psyload altitttde is less than a t!veshold. altitude (e.g., established via manual esgmeeririg input). Irs practice, fte threshold altitude may be a height above ground at which users eatt feasibly reach the payload and thus interac with the tether.. Othe instances are possible as well

|027SJ In yet a further aspect, the control system may operate the UAV itself ¾ accordance with a. UAV response process, which may involve at least a particidar movement of the UAV. In. praciiee, the particular movement could take ers. any ieasih!e forms. For emraple,. the particular movement, may involve side to side nioveriierst of the UAV: alon as axis in physical .space.. another example, rise particular movement m involve initiation of f rward flight along, a .flight path, as shown, by state 2506 of Figure 25 for instance. Other examples are possible as well.

|0276J General!y _i: the control system may operate the DAY in accordance with the UAV response process in addition to or instead of operating the motor in accordance with a determine motor e onse process. And if the control system does so in addition to operatin t¾e motor in accordance with a moiot response process, the control system may operate the motor and the IJAV, respectively, to carry out those p ocesses- simultaneously and/or at different times. Moreover, th control s stern ma operate the IJAV in. accordanc with the UAV response process after and x daring a user-interaction.

|0277 Yet mrther, the control system ma determine the OA.V response process based on various factors. Irs doin so, the control system!, may consider any feasible ^• combination of those factors, possibly giving more weight to some factors compared to others, Nonetheless, various factors a« possible.

|027¾} hi one example, the -control system may d termine the IJAV response process based on a detected operational pattern of tire motor. Fo instance;, the control system may have stored thereon -or may otherwis be configured: to refer to mapping data- that maps a phrralit of operatioBal patterns each with a respective IJAV response process. For instance, the mappin data may map a particular sequence of current levels with a tlAV response process involvin the operating the IJAV io tilt by a certain extent ami in. a ce tain direction As suck me control system may determine the UAV response process by referring to the ^• mapping- data to determine the respective UAY response process that Is mapped to the ^• de ected, o erational pattern of the motor. £02:79! In another example, the control .s stem may determine the UA ^' Y response process based im a state of the UAV ¾ environment and/or based on the liAV's state of flight; For mstaaee, if the control system determines that the UAVs state of flight urvoives the IJAV hovering over a first location 0» the groinid and that the stale of the tJAV's enykorimeot includes a use* physically pointing to a second location on the ground., ihm the lAV response process rosy involve the tlAV flying is hover flight so .as to end: up .hovering, over the second ioeatioH, saeo . as for pta oses of delivering a payioad at the second location for instance. Other examples and aspects are possible as well.

Θ280| it is noted that the afeove-descrfhed ieatnres related to user lote aciiosi'fcedoack are not limited M a siissiiart in which the IJAV is hovering sad could be carried otft in variou slteatioas- without departing frets the scope of the present disclosure. For example, the various features may be earned out irs a slittatkm in which the IJAV has laiided on a ledge and she tether has beet* at least partially uiiwouftd such tftai the tether is suspended by the UAV over an edge of the ledge:. Othe examples are possible as well.

Post-Oefiyery Tether Cofttrel

A. Release Verifieatiosi

|Θ28Ϊ J As noted above, when a U V lowers a payioaii to the ground: b ccaiirolling motor to unwind a tether coupled to the payioad, the control system of the UAV tmy isosltor the eiirrettt of the motor and/or the natation of the spool to verity that the payioad has reached the ground. he control system may then operate the motor is cause o ver-run of the tether b eoahmrine; to lu wiad: the tether fern the spool Once the tonehdown of the payioad is verified and tether overrun, is persfcnried, the control system may operate in a release- verification mode hi order to verif separation of the payioad from the payioad coupling apparatus, before begiraimg the process of lifting the payioad couplin apparatu hack, to the UAV.

!§2S2| Figure 26 is a flow chart iliasiraiing a release verification method 2600, according to an example embodiment MetSrod 26(30 m be initiated upon, the completion of method ,ί &ΟΟ te,g. _s at the end of the- tethe over-rua period), as part of operatioa ia the refease-verifieatiori mode,

|02SSJ As shows, method 2600 involves the control, system operating the motor in the frsi rnocle where torque is applied to counter the pull of gravity on the tether) for release- verification period, as shown by block 2602, In. practice, the control system may apply a .speed profile, designed for release verification. "Ore speed profile may be designed so as to lift tlie specific weight of the payioad coupling apparatus a swll distance durin the release- verification period Thus, if ^' the payload has riot bees released, the motor wiiH draw more current to fellow this speed profile, ttiaa it does when the pay load has bees properl released from the payload coupling apparatus. Accordi g y based at least m parte© the motor current during the . elease-venfieatioa period, the control sysiem may determine that the paytoad is separated fr m the payload coupling apparatus, as shown by block 2604, For instance, the control system, m detennine that the payload is separated f om he payload coupling apparatus by determining that the motor euitent during the relcase-vertficatiors: period: is ^' below a threshold current for at least a threshold »m¾rot of time. And. in res onse to this determination, the control system may operate the motor to retract the tether, as shown, by block 26M

|6284j Q the ©t e* hand, if the motor aarent daring the release-verification period ic large enough, then the control system ma determine that the payload has riot been separated from the payload coupling: apparatus, and may repeat the processes of operatin the motor to cause over-run of tbe tether (this time, erhaps _* f some predetermined additional length) and then puling upwards o» the tether to test for payload separation, shown in blocks 1808 nd ^" 2602 to 2606.

Tether Retr acti&u Processes

{flt¾85{ Once the release of th payload has een verified (e.g„ by perfo»rang method 2600), the control system may switch to a retraction mode, in order to retract the tether to lift the payload coupling apparatus back to tire IJAV.

286 lr» tbe retract ion mode, the ascent of the payload coupling apparatus may be divided into two phases: ait initial aseerit and final ascent phase.

|Θ28?| ^' Daring the initial aseerit, the control system may implement a predetermined ascent rate profile, which may b designed with the safety of bystanders and or surrounding structures in mm$. After the initial, ascent is complete (e.g., once a certain length of tether has been wound tip), the control system may pause the retraction process, _; © §., b operating the motor to nmiutaia a substantially constant length of unwound teflier.

|0288| Bae to the reduction in weight -sus ended from the tethe (e.g., the weight of the payload coupling apparatus only), the payload coupling apparatus may be more susceptible to swinging hack and forth once the payload is released. Accordingly, daring tbe pause in. the retraction process, the- ^' control sy stem ma evaluate whether the payload coupling apparatus is oscillating (e.g., as a pendulum) sad/or determine .the agaftude of osculations, and may evaluate whether actions should he taken to danipen the oseillatiQns. After or during such dafirping processes, the eontml system may initiate the final- ascent of the payload couplin apparatus, in which the tether retracts fully to pall the payload coupling apparatus to the UAV, anil seat the payload coupling apparatus iii-the UAY's receptacle for fie -tlight back to a return location.

j0289| Mote details regardin retraction of die tether and pay-load coupling apparatus after delivery are provided in refcenc to Figures 38A-38G below.

KL Dampin scillaiioMS of a Payloati

02 J IB practice, the UAV may sometimes encounter situations in -which the tedjer is at least partially un ound and a suspended payload eotipied to- ^' .the tether is susceptible to oxeillatiops. In one exatupie of this situatioB, the UAV m y deplo the tether for delivery of a coupled payload, thereby makin the coupled: payload susceptible o pseiilatiofts, la another example of this situation, die UAV may deploy die tether for pickup of a payIoad _; . thereby making the payload eoupBrsg apparatus (e,g, _s considered to be the payload in this case.) susceptible to oscillations, In yet another example of this .situatio , tfte UAV may retract the tether following eouplin of trie payload for pickup, thereby irtakiag the ^■ -coupled payload soscepdble to oscillations, in yet another example of this . situation _* the UAV may retract the tether following release of the payload after delivery, thereby making the payload coupling apparatus (e.g., again considered to be sJic payload in this case) susceptible to oscillations Other exam les are also ossible

f 02911 I such situaiioiss, va io-us factors rna cause oscillations of the suspended payload. I» one example, stiffieieotly strong irsd conditions ma cause the payload to oscillate. In another exam le, movement of the UAV to maintain Its position m hover mode may cause the payload to oseiilate. And. irt yet another example,. oscillations of the payload may be a resnit of an externa! force applied by a user to the tether arid or the payload itself Other examples are also possible.

Jfl2½ Oeueraily, oscillation, of the payload may cause the payload to move hack and forth hi a peud.«luni ike niotion, also referred to as peftdular motion, in practice, the pendnlar nroiion of an oserliating payload could have various eouseqiiences. For exarnple, the pendwiar mo ti on of an oscillating payload may have uBdesirab!e effects on the stability of the U V, may create difficulties in pOisitioth ig the payload in a desire location on fire ground, ma create an. itadesired mo vement: of the payload near the ground, or ma create difficulties in seating the payload coupling apparatus in the UAV-s receptacle, among other problems, |Θ293| To resolve these: problems, the UAV¾ coftrrol. system may perform one or more dapping techniques, such as those described, befo . As noted above, such damping techniques rnay be performe after delivery of the payload, during a -pause in die tethe jtta be mapped to an indicatio» that the payioad is oscillating, Aiso _!: another particular set of tether tension characteristics {&g., a partienlar rate Of cha«p in teuslorr) .ruay be ajapjjed to an indicatio that the payioad is oscillating with a atiie«iar speed.

|0297| in yet another case, the !MU may generate movement data indicative of movement of the payioad. relative to the aerial vehicle. The .control system ma recei ve such movement data and may use the movement data as basis for detecting, oscillations of the payioad as well as for determining attributes of those detected oscillations,. o do so, the control system, could refer to mapping data or the like that maps vaiioas charaetenspes of niovemeiii data eac with an indicatio of payioad oscillations and¾>t with respective attributes of payioad oseiRatiohs. for example, a particular set of movement data characteristics may he mapped to an indieatioii that the payioad is oscillating. Also, another particular set of movement data characteristics {©.^ movement data indicative of particula force) may foe mapped to an indication that: the pay load is oscillating w th a: particular atiipltiude of oscil!auom

|02 8| f» yet another case, tlse image captore device i y "be arranged to face the payioad and thus provide im e data representative of position of the pay ioad relative to the I .Y. With this arrangement, the control system .may receive me image data and may use any etirrent!y known aad or fwtttte developed image processing techniques to evaluate the image data, In doing so, the control system: may use the image data to determine: position of the payioad over lime. More specifically, the control system may detect oscillation of the payioad. by determining a ifference in position of the payioad over time. Moreover, the ^• control system could nse the image data as basis for determining attributes of detected oscillations,. For example,, the control syste ma determine a difieresce between certain payioad positions aver time and then determine amplitude of oscillation, based o the detennined difference. In. another example, the control system may xrse the image data to determine a rate of change in. position of the- payioad and thee determine a speed of oscillation based on the determined rate of change. Oilier eases and examples ate possible as well.

[0299 f Moreover, various attributes of payioad ose illations ma depend on the extent to whic the tether is unwound. For instance, a shorter unwound tether length may cause the payioad to swing with a higher frequency compared to a frequency ith which fee payioad swings when the unwound tether length: is longer. For this reason, the control system may consider unw und tether length as m additional factor when determining attributes of payioad oscillations. For example, after determining that -t e tether is unwound at a particular fe:Bgth _!; the eontel system may determine p i s -of the payioad: ver time. Then, -the control system may relet to mapping data that maps the combination the determined unwound length of the tether an the . ^. determined positions to a particula smpHtude of oscillations ami to jiic. ¾r fpe¾uettc - Alternatively _> the control system .am determine sttch attributes based oil a predetenMiied formula that inputs variables, sueh the .un ound: tether .length and detennined positions, a»d: that outputs data indicative of o.se or more of the abo ve-aieuti oned attrihiwes. Other exam les are also possible,

Θ3Μ1 ,!«. practice, the control system may determine the unwounef tetter length by receiving fern the encoder position data representati e of the unwound length of the tether. More speciftcs!ly, the escoder ftiay be ...coupled ^' to tbe motor ch m&L. as the motor carries oat rotation to unwind and or wind the tether, the encoder generated data represeJitative of an angular position andior motion of the motor (e.g., of a trai^mission assembly of the iBOtor), As such, the control system may receive the data and roay use the data as, basis fo tracking tbe nmvonnd length of the tether, for example, the control system may detect, two revolutions of the motor in particular direction based on tbe data from the encoder and may deternune that those two mvolMons correspond to unwinding of the tether by two insists,: Other examples are also possible.

|Θ30Ι In 8 tether aspect, the control system. may also use the sensor data as basis for deteouining the detected oscillations exceed a threshold (e.g,, _: established via manual engineering inptit). For example _* the control system ma etertaifte: thai the sensor data is indicative of a particular ampiinirle of die oscillations of the payioad, may determine that tbe partieular amplitude is higher than threshold, amplitude, In. another example, the control system that tbe senso data is indicative of a partieular speed of tbe oscillations of the payioad, such as a speed at which the payioad swings hack and forth while the tethe is partially unwound In this example, the control system may then determine that this particular speed is higher than a threshold speed, in yet another example, the control system that the sensor data i indicative of a particular frequency of the. oscillations of the payioad, such as a fequeney at which tbe payioad swings bach: and forth while the tether is partially unwound. In this example, the control system may then determine that, this partieular :iret a:eney is highe than a threshold frequency . Other examples are possible as well, 1. aiHjjiiig during a 'fe her Retraction Process

| ^' 0392| ^• F gHfc 2? is a -flowchart illustrating a method.2700 for initiating a damping routine (eonld also be referred to herein as a damping technique , according to an example emhodiment Metho 27f> may be implemented: by a UAV's control system during a tether retraction process, la practice, the teiher retraction process ¾¾r be carried ovii alter delivery atid/ at -other dtae during pick-up aad or delivery. Moreov r, -although aaethod 2700 is, described as being carried oat its the context &f a -payioad eottpiirrg a aratus, method 27CK) could also he carried oui fe the coatext of a pay-load coupled to the payioad coupling apparatus.

j¾¾Bjr Turning to iBethod 270¾, the UAV aia mitially be -operaffeg _: in a hover iight mode, as shown ^' by block 2702. For .instanee _s the UAV may hover over a target or delivery location; or over a source location; Onee the- payioad is released on the ground, the UAV's control system may switc t a tether retraction mode, as shown by block 2702. While operating, in die tether re tractioti Mode, die control system may perioral a damping routine to dampen the oscillations of the payioad eonplhig apparatus, as shown by block 27 4, O tionall ; the corrtroi system may do s specificall response to deteimining that deiected oscillations exceed a threshold,

3M| Generally, die dimming routine that the control sysiern performs may he any combination of the damping routines: described herein, in some cases, however, the control system raay peribrr« one or more .dashing routine other thos described .herein and. -do so wiihoai departing fora the scope of method 2700.

| 30S| As rioted, above, a .damping rotAe, sneh as that peribrrnsd. at block 2704, ma be carried oat during pause in th ascent process {and perhaps dining; -a pause while lowering the payioad coupling apparatus as well), In some : ernfcodhirents, the control system may waif until the oscillations are . sufficiently dampened before resuming the process of retracting (or lowering) the tetite For exam le, the control system may pause .until ^' it: determines that the amplitude of die oseifiaiioas is less than a threshold affiplitude, or possibly even thai the payioad eonpiing apparatus is resting In an eqitdibritsri position. In either ease, the control systera wa responsively resume retraction of the tether to lift the payioad coupling, apparatus to the UAV. In other smbodinrents, however, the control system may not wait until the oscillations are sufficiently dampened before resuming tlie process of retracting (or lowering) tlie tether. Bor example, die control system might pause the teiher retraction process fo fixed period of time before resoniiag. Speciieally, upon starting perforaiance of the damping routine, the control system may initiate a timer thai is arranged to expire afc a particular duration (e.g., estabhsl¾d via manual engineering input), and may resome the process of retracting (or lowering) the tether in response to detecting espirahon of that timer. Other examples are. also possible. |Θ30&| Figures 28A to 28D next collectively iliostralc ifiiiiation of a daaspiag r itthie during a tether r^iractioii po ess,

(0307 As sh wivby figure 28A, a UAV ^' 280 includes tether 2802 and a payioad eonphng apparatus 2804 coupled to the tetter 2802, Also, a payioad 2806 is shown as having been, delivered by the UAV 2800: at a delivery location . oft the ground. Moreover, Figure 28 .shows- that die UAV 2800 Is bowing over the dehvery focattoa while the ^' ;0AV ^* s control system operates the tether retraction mode to ascent tie payioad coupling appamttis 2804 ^' back to the UAV alter delivery of the payioad 2806.

03 1 As shown by Figure 288, while operating in. the tether retraction mode, ,ite

0 A V's control system passes the aseeat of Ike payioad eoyplmg appara¾ts 2804.. During ike panse, the control s em performs a damping: routine, as indicated by Figure 28B, As noted,, die damping routine coald be any of the damping routises described tereiB. amsrsg otters. Optionally,, as noted, the eoap-ol system performs t e damping routine in response to deteeiirig that oscillations of the payioad coupling apparatus 2804 ₄ ¾¾ t oscillation amplitude 2808 that is greater than a threshold. aniplitode,

03©9| As .shown fey Figure 28C,. while the U& ¾ coBtroi sy stern still pauses aseeat of the payioad- couplisg apparatMS 2804, the osclllatioas are shown to have been dampened due to the daatpiu routine, 1B enes case, dating the pause sad -after carrying out of the dampin routine for some time period, the control system detects that oscillations of the payioad coupling apparatus 2804 are at as seillidton ssnplstede 28i0 that is lower than the threshold: amplitude. Jn this way, the eontrcd system deterralafes that the oscillations have bee sufficiently dampene and responsiveiy determines that the tether retraction process m resume. In asother case, the costroi system detects expiration of a timer initiated: npea starting performance of the damping routine, and determines that the tether retraction process may resirme is response, to detecting expiration of that timer. As such, at either ease, the control system ma responsiveiy resume operation in the tetter retraction mode t ascent the payioad coupling apparatus 2804 back t the UAV 2800 after delivery of the pay-load, as shown by Figyre 28D, Other iiluste tions are also possible.

(.;, x m le Dam ing Tecisiiiqii s

|0310| Although several damping- iechtti< ues are described below, it should be understood that other damping teehtdques arid modifieadous to the described fcc&iitpes m possible as well withoat departing from the scope of the prcseat disclosure,

1 Forward Fiight to iJampm Oseilhiio (0311} Figure 29 is a !lowehart illustrating a metho 29W for initiating forward Sight to dampers oscillations. As noted above, the UAV may be configured to- fly in accordance with a hover Sight mode and hi accordance with a forward Sight mode, & hover flight rnode, flight dynamics may be similar to a helicopter. More specifically, lift an thrust may be supplied by rotors that allow the UAV to take off and land vertically and fly in all directions. In for ard- Sight mode, however, Sight dyaaittscs may be similar to an airplane. More specifically, a fixed-wing UAV may be propelled forward by thrust from, a jet engine or a propeller, with fixed wiiigs of the UAV providing lifting and allowing the UAV to glide sub uimiaily horlzotnaily relativ e to the ground.

J83:l| With, this arrangement, the U AV ma operate accordance W'ih hover Sight mode, as she n by Mock 2002. As noted, th . UAV may do so daring a process of deploying the tether for payload pickitp and/or for payload deli ver};', or may do so during a process of retracting the tether for payload pickup and/or for payload. delivery. Regardless, while the UAV is ifi the hover ^' flight mode,. the UAV's control system may cause the UAV to switch from the hover flight mode to the forward Sight mode, as shown by block 2904,

(931.3| Optionally, the control system may do so its response to determining that detected oscillations exceed a fteesho!d. Also, the payload at issue may be considered to be a payload (e.g., a package) that is couple the payload coupling apparatus or may be considered to b the payload eoupliag apparatus itself, among other possibilities.

031 | Mote speeitMuy,. by switchin to the forward Sight rnode, the m vement of the UAV ma resdt in drag OK the payload. Generally, drag is considered: to be an aerodynamic force or friction that Opposes or resists an object ^' s motion through the air dtte to interaction between the object and molecules of the air. So in a forward Sight scenario, airflow may result i» drag that is directed along a direction opposite to the direction of the forward Sight. Thus, the resulting drag may dampen the detected oscillations of the payload because the airflow .may Kelp stabilixe the payload,

| 31S| Furtheraiore, in some embodiments, when the control system eaases the UAV to switch, t the for a d iliglit mode, the control system niay aiso direct the UA V to operate in the forward flight rnod with: certain flight characteristics, i . practice, these Sight, characteristics ma incinde Sight speed. Sight direction, and/or flight timing, among other possibilities. As sueh, the ^' control, system may determine the appropriate Sight characteristics based on various factors,. And in accordance wit the present disclosure,: the control system rnay determine the appropriate flight characteristics based at least on the detected oscillations of the payload and/or based on other factors. (Θ3 | By way of example, she eeatrol system may detenttine an initial flight speed for the. forward ^' flight mode based at least on me detected oscillations. In practice, the initial flight speed may be a flight speed to which the li&V initially accelerates immediately ate" swtteiliag to forward flight nlode ami one which the UAV ultimately aiaintatas for at least some time period dating the forward flight mode. So in. accordance, with ike preseat disclosure, ike control system may determine an initial flight speed that is generally higher when amplitude of the detected oscillations is eater For instance,, the control system ma select a first initial Sight speed when, the eoatrol system detects a first amplitude of oscillation of the payload and may seleet a second initial flight s eed when t e control syste , detects a second ampltftfde of oscillation oi ^" the payfoad, with the first amplitude being higher tlian the second amplitude asid die first initial flight speed feeing higher than the seeoad initial .flight speed,. Note that the initial flight speed may additionally or alternativel depend on mass andior drag of the ay load, or ma simply he predefined via. manual engineering input or the like,

f03i ^' 7J in another exam le _^ the control system ma determine flight timing for the forward flight mode based at least on the detected oscillations, in particular, determining flight timing »¾ay involve determisiisg a time at which to initiate the forward flight mode, a duration for which to carry out damping as part Of the forward flight mode, and/or a time to ea:d the forward: flight mode, among oilier possibilities. In either ease, the control system may consider various factors related to the detected oscillations as hasis. lor deterrainia the flight timing. For instance, the control system rosy determine state of the payload: swing, such as whether the payload. is at top of a swing or a bottom of a swing, and. use that determined slate of the pay load swing as basis for determining the flight timiag. la another instance, the control system may determine an extent (e.g., amplitude) of payload oscillatioas and may determine the flight ^' tinting based on the determined extent. Mote that the flight timing aiay aitemaiiveiy be predefined, via manual engineering input or the like. Other instances and examples: are possible as well.

ύ3ΐ8| :hl a further aspect, the control system may help facilitate the forward flight: damping .rantine is various situations. In one example situation, the control, system ma initiate forward flight to dampen oscillations during a process of refracting the tether for payload piehup and/or for payload delivery. In this example situation, the control system could technically initiate 'the forward flight at any point of the retraction process, sireh as without a pause in the retraction: process. Ideally, however, the: control system, may operate the motor to pause retraction of the tether while die detected oscillatioas exceed the threshold, which ma allow the control system to initiate the forward f%ht mode during the p use in the retraction process. Then, once the control system detects dtat oscillations of tfee payload tee ten sitfficieat!y /dampened by the drag (e.g., that the detected oscillations HO longer xceed the thteshokl] and o after a .fixed time delay (e.g., in response to- detecting expiration of a timer), the control system may then operate the motor to resume retraction of the tether,

03i9j In another example sihtahoa., tfee -control system may initiate forward flight to dampen: oscillations during a process of de-ploying the tether for payload pickup and/or tor payload delivery;. I this ex m le situation, the control system eouid technically initiate the forward flight at any point of ^* the deployment process, such as without a pause in the deployment process. Ideally, however^ tile control system may operaie the motor to p use deployment of the tether while ihe detected oscillations exceed the threshold, which may allo the control system- to initiate die forward flight mode during the pause in the deployment . rocess- _* Then, once the control system detects that oscillations of the payload have been sufficiently dampened by the drag and/o afte a fixed time delay (e.g., in response to detecting expiration of a timer),, the control system may then operate the motor to resume deployment of the tether .. Various other example sft«ations are possible as well,

f 0328 Yet ^' farther _* , when the control system operates the motor to resttrse deployment or retraction of die tether, the control system stay ideally do so while the ϋ A V operates in the forward flight Mode, hat could, also do so While the UAV operates in the hover flight mode, |032i| or example, once the control system detects that oscillations of ^' the payload have been sufficiently dampened by the drag and/or after a fixed time delay, the control system may responsivel operate the motor to deploy or retract the tether as the control system, also causes: the ^' UAV to continue operating in the forward flight mode. Also, in the context of retraction for instance, the control s stem may direct the UAV to m intain a particular for ard flight speed (e.g. ₅ the determined initial flight speed) as the tether is being retracted- In this way, ie control system ma ensure safe and steady retraction of the tether. Then, once the control system determines - ^' thai thai tether retraction is complete, the control system ma then responsivel change (e.g. _S; increase) the forward flight speed, if applicable, 322 Additionally or altematively, ones the tether has been fully refraeted, the control s stem: conld then cause the liAV to switch from the forward flight mode back to the hoyer flight mode, la this regard, after the UAV switches bach to- the hover flight mode, the control system may then operate the motor to deploy the tether. n this way, the forward flight may dampen oscillations of the payload and subsequent hover flight may allow for dampens the oscillations of the pay load coupling apparatus 3004. Accordingly, during the panse and after the UAV carries out for ard Sight lor sons ime period, the control system detects that oscillations of the payloa coupling apparatus 3004 are at oscillation ampltttde 3012 that is lower than the threshold aMplitu e.. lit this way the control system determines t ai the oscillations have been sufficiently dampened and resporisiveSy determines that the tether retraction process may resume.

[&3 Ϊ As s ow , fey Figure 30ί¾ in response to eternnning that the oscillations have been sufficiently dampened and/or in response to defecting -evirat on -of :aii«ier &e control system, iheii resuraes operation in the tet¾er retraction mode o ascent die payload eoapling apparatus 3004 hack to the UAV $ 00 : after delivery of the pay load Moreover, the control .system is shows, to resume operation in the tether retraction mode as the control system continue directing the UAV 3000 to operate in forward flight .mode. Other illustrations are also possible,

it Reducing, an Extent of Flight iStiiMiiz ian to Bwnpen O ilaimm

10329f In accordance with an example imp! emeutation, the UAV may be operable in a p08iiioa»hold mode in which the UA salistantially maintains a physical position in physical space duriag hover flight. Cieaerally, the UAV may do so by engaging in one or more tltght .stabilization techaiattes t®, -, vision-based stabfcarion and/or IMU-based- stabilization) daring hover flight, such as stabilization techniques that are carrently known and/or those developed hi the future.

|0330f Specifically, the UAV ^' may engage in flight stabilization alon three dimensions in physical space, so as to resist movement of ilie UAV along any oae of those three dimensions and thus to help maintain, the UAV ^' s physical position, !n practice, the three dimensions at issue rmy he the aw axis of the UAV, the pitc axis of the UAV, and the toll axis of the UAV _* Additionally r alternatively, the three dimensions may include any feasible translational axis for die UAV (e.g., any axis along which translations! move ent of the UAV is possible). But the three dimensioas eoald also take on various otljer fortas without departing from the scope of the present disclosure

[03311 Ft gate. 31 is a flowchart illustrating a method .3100 .for re iieing an extent

(e.g„ gains) of flight stabilization io: dampen oscillations f ^* go limp" damping technique). As shown by block 3102 of method 3100, the UA V may operate in the position-hold mode. Here again, the UAV may do so .dur n a process of deploying the tether for payloa pickup, and or for payload del fvery, or may do so during process of retracting the ¾ther or pay load pi$k¾p and or for payload delivery. Regardless, while the O ^' AV is in the posiiion-hold mode, the

one dimension at issue, energy may dissipate over time, thereby resulting m dsnming of the detected oscillations due to this energy dissipation,

f0333| In accordance with the present disciosure _S: the act of reducing m exten of flight siabili¾atio¾ along the at least oae dimension ma take variou forms.

03 4] In one ease, .reducing an extent of flight stabilizatio along the at least one dimension, may take the form of completely e|ii«isiat«)g. asr ^' fmm of staMli¾»tio» along that dimension and thus allowing the UAV to move along that ditneasioa strictly based on application of external fbrees to the UAY, For example, a swinging pay load rnay apply as external feree to the OAV alon a: particular axis and, doe to the IJAV :toduei« stabilisation along the parh ^' cular axis, he IJAV may end up moving along the particidar axis by aft a oun that is based oft a magnitude of tihat externa! force. In this way,, the swinging payload ma essentially drag the U ^' V itself alotig the particular axis. Other examples are possible as well

103351 in another case, however reducing an extent of flisht siabi ¾ati.on,a1o5ig the at least one dimension, may take the form of reducin the extent of stabilization along the at least one dimension fey certain, extent Speei fiesliy, the control system &y allow the ti AV to move alon the at least one dimension based on application of external forces to the tJ AV, but do s only to a certain extent. For example, the IJAV ma engage, i flight stabilisation after detecting some extent of raovemeiit of the DAY along the at least one imension relative to the above-mentioned physical position. Is this way, the control system may effectively allow some range of movement of the flAV along the at least: one dimension relative to the pbysieai position (e.g.. tip to a two meter translational moveineel of the ttAV a!CKftg a partieute ^' axis in each direction) _* rather than the AV attemptitig to niaiaiain itse UAVs physical position by relisting any moveme» of the UAV away from that physical position.

}¾336| Moreover, the control system, may consider vatso¾s factors when. determining the extent to which to reduce stabilization along the at least one dimension, in an miph im ie«ientation _i: the control system may use the detected oscillations as basis for determining a target extent of siabilization. hi doing: so, the control system .may determine a lesser target extent of stabillzaiiori when the amplitude of the detected oscillations is greater, thereby allowing for greater inovernent of tlic UAV along the at least e dimension so as to help dissipate energy. And du to sweh greater movement of the UAV, the higher atiifsllfedc oscillations ma ultima tely dampen. Other eases and examples are also possibly,

f §3371 .Following redaction of flight stabilization along the at least one dimension, the control sys em -may detect that, oscillations of the pay load a e hecB sBfficieBtiy dampene ■and/or may detect expiration of a tinier (e _; .g., initiated at the $&rt-of #ι©·%>· i««p" ^' da in routine}, and may ras e , slvely caitse the aerial vehicle to increase an extent of flight stabi 1 ization alon the at least one dimension, to ccor ance with the present disc losnre, sneh increase of flight stabilization eotild take on various forrns.

f#338| In ooe exam le _* assiiniN that the -eonirol ^' system caBsed. ΐί>¾ HAY to completely eliminate any form of stabilisation along thai dimension, the control system may cause the UAV to completely activat siabili»atio¾ along tfaat dimension is an attem t to: fiiily raaiatain the UA V's physical position, la aaeihef example, again assuming that the control system caused the IJAV to completely eliminate any form- of stabilization: along that dimension, the control system may cause the IJAV to increase an extent of siah.il ixatlon along tha dimension by ei&etively allowing some ra ge of movement of the UAV along the at least one dimension relative to the physical position, la yet another example, assuming, that the control system caused the UAV to partially r uce the extent of stabilization along: the at least one dhnensioa, the control system may cause the UAV to increase the extent of stabilization along that dimension la this ex m le, the control system may cause the AV to increase the extent of stabilization (e,g., to the same extent prior to the reduction), s as to effectively .lessen the allowed range of movement: of the UAV along the at least oae imension relative to the physical position. Alternatively, the control system .may cause the UAV to increase the extent of .stabilization- $$· as to completely activate stabilization along that dimeiision hi a attempt to full maintain, the UA.V's physical position. Varions other examples are possible as well. f0339 . In a further aspect, the control .s stem may help facilitate th ^* ¾ hel "

-daia iii ^technique h ieus situations. M one example situation, the control system may ^' Imitate ^' the ^' *¾ø limp" damping techni ue during a process of retractiog me te er for payload pickup an.d ot for pay toad ^■■ delivery, In this example situation, the control system, could technically initiate the "go limp" -damping technique ai any point of tile retraction process, .such as without a pause in. the retraction process. Ideally, however, the control system- ma operate the ^■ .motor to pause retraction of the tether while the detected oscillations exceed, the threshold which may allow the eaatrot system to initiate the "go limp" ¹ damping technique during the pause uj die retraction process, Then, once tlie control system detects that Oscillations of the payload have been sufficiently dampened Mo i g reduction id me extent of flight stabilization along at least one dimension (e.g., thai the detected oscillations .ho longer exceed the threshold) and/or after a feed time delay (e.g,, upon detecting expiration of a timer)., the control system may t en operate the motor to resu e retraction Of the tether, p349j In another example situation,, the control system may initiat the "go imp" damping technique during a process, of deploying the tether for payload pickup and/or for payload delivery, |a Shis example situation, the control system could technically initiate the "go Im¾}" damping technique at- any point of the deployment process, such as wiihoKt a pause in the deployment process. Ideally, however, the control system may operate the motor to pause deployment of the tether while - the -detected oscillations exceed the threshold, which may allow the control system to initiate the "go limp'' damping technique during the pause in the deployment process: Then, ou.ee the control system detects that oscillation of the payload have been safiicienily dampened following rediaeti n in the extent of flight stabilisation along a least one -dimension, and/or after a fixed time dela (eg., upon detecting expiration of a timer), the control system ma then operate the motor to resume deployment of the tether. Various other example .situations are possible as well

f 03 11 ^" Yet further, when the control system operates the moto to restaae deployment or retraction of the tether, the control system may -do so while the flight stabilization along the at least one dimension is tiii reduced, aed or after flight stabiiigatioR along at least one dimension has been increased. For example, once the control system detects that oscillation of the payload have been sufficiently dampened, and/or detects expiration, of a timer, the control system may responsively operate the motor to deploy or retract the tether as the control system als eauses the UA V to maintain reductio in the extent o fttght- stabilization along the at least one dimension. In anothe example,, once the control syste detects that oscillations of the payioad have heen sufficientl dampened and or detects expiration of a timer, the eon&ol system may responsively cause the UAV to increase tire -extent of flight stafetimatiofi along the. at least one diaKaslon. In this example, after the UAV increases the ■•extent of flight stabilization along the at least oae dhneiision, the control system may then operate the motor to deploy or retract the tether. Other exarriples are possible as well

|0342| Figures 32A. to 32H next collectively illustrate fee "go. limp" danipin technique, specifically feein carried out during a tether reir action process,

[0343 J As showri: b Figure 32A _S: a- ^' UAV 3208 sacl des tether 3202 and a payload coupling, pparatus 3204 coupled to ifee-tetjher 3202. Also, a payload 3206 is shown as having been delivered b the ϋ AY 3200 at a delivery location on the gro nd, Moreover, Figure 32 A s ews that the U ^' AV 3200 is hovering, over the delivery locatioa while the IJAV's control system operates in the tether reiraetioa mode ¾> ascent the payload coupling apparatus 3204 hack to the UAV after delivery of the payload 3206. Irs this regard, the UAV 3200 is shown as being in a- -position-held, mode .¾» which the UAV 3200 substantially maintains a physical positi ii. ^* 'Χ,Υ ^>5 in physical space during; hover flight.:

|034 As shows, -by Figure 32B _S while operating in. the tether retraction mode, the

UAV's control system pauses the ascent of the payload. ^■ coup-Bag apparaws 3204. During the pause, the control sy tem optioaally detects thai oscillations of the payload coupling: apparatus.3204 are at at), oscillation amplitude 3208 that Is greater .than a threshold amplitude,. Responsive to detecting oscillations is this manner and or responsive to Initiating a timer, the control system then perforins tire ahove-descrifeed "go limp" dampin routine. It* particular, the eoaltol system -causes the IIAV to reduce an extent of fl ight stabilisation along at least one dimension. By doing so, the UAV then moves along that dimension based o application ^■ of external forces to the UAV, which, may dampen oscillations due to energy dissipation. Such movearent and energy dissipation is illustrated by Figures 33C to 32F.

J034S| ore specifically, due to reduction in the extent of flight stabilisation along the dimension, the swingiag payload coupling apparatus 3304 drags the UAV 3200- iu a first direction -alon the dimension to a position that is at a distance Dl away from position as shown b Figure 32C. Subsequently _s . dire to continued redaction la the extent of fligM stabilization along the ditneasioa and due to energy dissi ation _s , the swingiag payload couplin apparatus 3204 drags the UAV 3300 i» a second direction (eg,, opposite to the first direction} alon die dimension to a position that is at lesser distance 02 (e.g., smaller thaa Dl) awa from the physical positio "X,Y" _S as shown by Figure 32D. Snbse uently, again due. to continned reduction m the extent of flight stabilization along the dimension and dee to furthe eaergy dissipation, the swinging payload conpiing apparatus 3204 drags the UAV 3200 in the first direction along the dimension to a position■ that is at an even lesser distance D3 (eg., smaller than D-2) away ran* the physical position ^' ,Υ", as showft by Figure 321. Finally, again 4m to. eoni aed reduction in the extent of flight stabilization -aloag the dimension and due to yet farther erter y dissipation, the swinging payload coupling apparatus 3204 drags the UAV 3200 in the second direction along the dimension to a position that is at an. even lesser distance D4 (e.g., smaller than 03} away from the physical position "X,Y", as shown by Figure 32F . In this awner, the UAV 3200 may continue moving hack and forth along the dimension as energy continues dissipating,

|034i>f As next shown b Figure 32¾ the oscillations a shown to have been dampened due to the "go limp'' damping routine. Optionally, during die panse and after carryin out of the "go limp- ' damping routine for some m»e period, the control sysiern detects that oscillations of the payload eonpiing apparatus 3204 are at an oscillation amplitude 3 10 that is: lower tha the threshold amplitude, ha practice, the control system ma carry onl such detection while flight stabilization is still reduced, along the d mension ■snd or after the control system increased flight stabilization along the dimension. oaemeless, the control system determines that the oscillations have been sufficiently dam ened and/or detects expiration of a: timet, and tssponsiveJ determine thai the {ether retraction process rna resume. As such, the control system may responsively resume operation in the tether retraction mode to ascent the payload coupling; apparatus 3204 back to the DAY 3200 after delivery of the payload, as shown by Figure 32H, Other ilhrstrations are also possibl

UL lfnwi0ing Wit}< ng Tether ϊϋ Detypm (Mcii iians

Θ347| In aecordan.ee with an example implementation, the IJAV control system, may dampen oscillations of the pay load b operating the motor to nnwind; and/or wind the tether, thereb changing tension on the tether, in doing so, the control system, may increase and/or decrease the unwound te;ther length and do s at various rates, which may help dissipate energ and thus ultimately dampe the oscillations of the payload. In this aimer, the control system is provided with an additional control input that does not necessarily interfere with the other control objectives of ^" the system ( .g., does not pr vent the vehicle from holding position while aiso dampi g paytead oscillations),

|Θ348 More specifically, the control system may operate the motor to vary a retraction rate of the tether and/or a .deployment rate of the tether, in practice, the retraction rale may define timing, ex ent, and/or speed of tether retraction and the deployment .rate rnay define timing, extent, aad or -speed of tether deployment. As such, the control system may may operate the motor m tie ^' 'first mode to retract the tether at the at least one target ^' retraction: rate (e.g., tfefe ed ^' based o detected ©scllladotis and/or established via manual engineering tnpnt), _: Addition lly or alternatively, the control system may operate the motor is fee second niode to deploy ihe tether at fee at least one target . deployment rate (e.g., determined based on detected oscillations and of establishe via manual engineering input). With ^' this arrangement, the control systesa could thus use various specific .approaches for damping oscillations via control of the tether at varions rates.

J034 J For instance, the control system may control the winding and or umvindiug of the tether, or the rate of winding and/or re in in of die tether to "pnrnp" "the payload ranch like a .swing, with tether let out as the pay load moves toward the bottom of the swing nd the tether held fast (or even wound in) as the payload m ves towards the tops of die swing. Moreover, a ''punipiiig" feqnene , period, and/or phase of the tether may he respectively -matched/to an oscillation frequency., period, and/or phase of the payload. By doing this, the energy f ihe swinging payload may be removed even as the UAV remains su stantially stationary.

iOJSOf Furthermo e, the extent of "pu-tnping" of the winc .may depend on the distance between die payload and the C¾V, whic corresponds to the nttwontid length of the tether. SpeotScally when there is large dista&efc- between the payload and the UAV ^" , the eadwiar motion of the payload ma he very slow. On the order of ¼ hertz for instance. At this point, the aninuni of the tether unwound o wound onto fee winch dnrin "puraping" of me ^' winch may he a the order of meters. ut whes the payload is closer to the DAV, the pendnlar motion may speed up to o» the order of 1 hertz or more for instance. In this ease, die amount of the tether unwound or woun onto the winch during "p mphig" may be on the order of centimeters.

| 35l I Yet &rther, the rate of speed at which the tether is wound or nnwoimd may vary from one period of oscillation to die next as the distance of die payloa to the UAV changes, and stay even be varied within a. single period of oseiHatton, For ex m le^ me rate of winding or uawindisig may he proportional to me velocity of the payload or the velocity of the payload squared. Other examples are possible as well.

| 352 Wife this arrangement, the control system may ^ rn ' ^' fee winch while operating in me tether retraction mode to engage in ascent of the payload. or whtie operating in the tether deployment mode to engage in descen of the payload Specifically, during descent of the payload, the oscillations of die payload may be damped by letting tether out at a the payload approaches die bottom of the swing. Whereas, when fee payload is moving towards the fop of the swing, the amount of tether unwound hrotn the winch could be reduced or stopped, or the tether cmM even: be wound in as the payioad moves to the top o the s ing. Such ' ^{^} um ng" of the tether ί&ψ counteract the pendBlar motion of the payioad to control and damp the oscillations, of the pay-load. Is contrast,, daring ascent of tile payioad, the oscillations of the payioad may be damped by winding the tether in as the payioad moves to the tops of the swing. Whereas, w en, the payioad is moving towards the bottom, of the swfe _s . the tether eoul be unwound, or stopped _* or wound: & at a reduced rate _* Other approaches are possible as well.

iv. IM M&vem i ί&. Dampen QseMat ns

J9353 in accordance with an example implemeniatroiik the lIAV's control system may dam en oscillations of the payioad by directing the IJA.V itself to move i various ways mronghout physical space. With this approach, the control s stem may direct the IJA to reactively m e in a manner that offsets, prevents, or reduce movement of the payioad during ascent and/or descent of the payioad. Although various such movements are described ^' bfetow _* other movements are possible as well without departing from, the scope of the present diselosure,

{0354J More specifically, the. contr l system .may he operable to deterintne a target path, of the paytoad This target path ma be a target path of ascent of the pay ioad daring Winding of the tether or .may he a target path of descent the payioad during. unwinding of the tether. For example, the target path may be -substantially perpendicular to the ground, and may ex send fern the ground to the: UAV. In this way, the ^■ control system may eft¾c»ve y plan to maintain the payioad substantially beneath the UAV as the payioad i being lowered or raised. Bat oscillations of the payioad may cause the payioad to move away from the target path as the pay ioad is: being lowered or raised,

| 30S| To help solve this problem, as noted, the control system may cause the UAV to move In various ways. Specifically, at a given point hi time, the control system may use the detected oseillations of the payioad as basis for- determining a position of the payioad. relative t the target path. Then, base cm the determined position of the payioad relative to die target path, the control system ma determin a movement to be performed by tire UAV so as to move the payioad closer to the target: path, and the control system, may cause ihe UAV to perform that determined movement As such, the control system could repeatedly determine such, - ^' movements as position of the payioad. relative to the target path changes over time due t oscillations, and eosid repeatedly cause the UAV to perform the: movements to help dampen the oscillations.

SI f0356 By way of exam le, the peadn!ar ation of the pa.ykad could be controlled, fey moving or translating the IJAV tikettiafiy in response to the motion of the payioad, e,g. by attempiirig to mMmi the payioad beneath the UAV. Oscillations of the payioad (e.g., pendulunl-like swinging) would be damped fey having the UAV translate (e.g.. move back and .forth) in such a way that th oscillations are minimized. For instance, the control system ma determine .that a curfent position of the payioad is at a particular distance away (torn the target path and that the payioad is currently -moving, in a particular direction relative to the target path. .Res ansive!y, the control system may i niediately cause the UAV to horizontally move in the particular direction and do so by an aiponni that is based oft the particular distance, thereby attempting to maintain the payioad beneath the UAV,. in this manner^ the control system may reactively determine horizontal movenienis thai offset horizontal farces on tlie payioad, and prevent or damp the oscillation of the payioad, Other

destination as soon .the payload has- beea. delivered. Whereas, the eoslroi system may select the UAV movement, damptag; technique if the DAY is engaging ia post-pickup tette rettactiofl. as part of the ptyioad pickup mode _s and do so because the FiAV movement may help ensure that the picked u payload is frequently located directly beneath the UAV as the. payload ascends, towards the UAV.

|9363| la vet another case, the control system may -select the one or more dampin ronting based, n a value of the payload. In raetiee _:; the value of the payload ma be a price of the payload. aod or may be a priorit of the payload being delivered, among oilier options. f¾iethe1ess, t e control system ay detertnine the value of the payload based on input pro vided by a user and/or by using object rec¾galtion techniijtie to determine the val se of the payload based on image data, among other possibilities. With this atraslgenienvthe control system ma refer to mapping data that maps each of various yahtes with a damping routine: or with a combination of two or mom damping routines. For exam le, the map in data may map higher ^' values- with the "go limp" damping techniques because the "go limp ^{5 '} technique may pose minimum risk for damaging a higher value payload. As suen _S: the control system may refer to the mapping data t deterame one or more dampin routiaes that correspond: to

controi system may select the ^mvin i g wradln of tdths ^* damping technique so as to avoid any movement of the UAV resulting from engagement in any of the ther damping techaiques, mereby avoidiiig coliisiois with the object. Other cases are possible as well 0365| :hl a further aspect* when the control system: selects one or more dampin routines,, the control system may also determine duration far which to carry out each selected, routine (e.g., a duration for which to set the above-mentioned timer), if feasible. Ia practice,, the control -system may determine each such iteration- based on one or more of the above- described factors and/or ma determine each such duration in ot er ways, For example, the control system, may determine that a. selected damping outine shonld be applied for a longer duration when the amplitude of die-detecte oscillations Is greater, ierehy allowing enough ^• toe to sufficiently datttpen the oscillations. Alternatively, the control: s stem may simply erioral a selected damping routine tmtil ^' the eoatrol system detects thai tie oscillations tee em sisfikient!y dam ened. Other examples are also possible,.

[0366 J la yet a farther aspect, wllen fee control system, selects t or more damping routines, fee control system may also determine as approach for using these selecte damping routines in confoisKitioa hi practice, the control system ma determine that approach based on : Oiie or more of the above-described factors aaeVor may deteraiine the approac In oilier ways. Moreover, although ex mple approaches are described below, other example isppfoaches aie also possible wld out departing fi'o the scope of the presen disetesure , { ^' 0367 j Ί». one: ema le approach, the control system may detcHnlne a se uence is which to nse die selected damping rotttkes, such as by determiahlg that a first damping routine should be followed b a second damping retniBe, For instance; the control system nia determine that the "go limp" clamping technique should be performed followed by performing of the ¾iwinding/wi«iii«.g of teiher ^M damping, techn ue, ft this regard, the control system ma determine that the second damping rontiae should begin. immediately followin the end of the first dantping routine. Aiteiiiativeiy _* the control system ma dete mine that the control system should wait for a particular time period after performing the first damping -routine- and foes perfo m the second damping rontine upon- expiration of the particular time period. In some esses, the control syste raay ese the particular time period to evaluate the detected oscillation and: may decide to niove forwar with performing the -second dampin roatiae only if the oscillations havcin** been siiflelerrily dampened.

{&36SI In anothe example approach,, the control system may defiermine that the

-control system should concurrently perform two or more selected damping routines.. For instance, tiie control system ma determine that the control system should concurrently perform the UAV movement damping technique and the imwroding nding f tether damping technique. In this regard, die control system may determine that the control system shonld start performing the selected amping, routines at the same point in tiaie. Alternatively, the control system, ma determine that the eoatrol. system Should start performing a first damping routine and, in fee midst of perfoi ning that first damping routine, begin perferBiirsg a second damping routine. Other example approaches and eombirsations of ^' the- deseribed a proac es ¾re-. possible- -as well

,E. Additional $ &iBping Aspects

|Q36f | Alfeough various da i g techniques- are described e ei , as being carried out after or responsive to detecting oscillation: of a ayioad. the various damping techniques aiay be carried out ia. olhcr sitaatious as well. For instance, the control system may be configured to Carry onl one or mere damping teehnifpe during certain phases of flight aa ¾ durifig certain phases of payioad pickup and/or delivery, aftieag other possibilities. In this instance, the control system, may carry mi those - amping tsehni aes wii!iotii necessarily detecting oscillations f a payioad. In ihis regani, as noted, fte eotttrnl system ma carr out the datnpmg routine for a certain time period, such, as b iiitiatmg a time upon start of a damping rontee and then ending the damping routine (and/or carrying out other .■operations, sech as resuming tether retraction) responsive to detecting expiration of that timer. In this tttaaner, the control system, ma essentially take preventative aetioas t» ^: aiiaimize any oscillations that might he present

ll. Faitere Beteetfen and Correction Methods

A. Failure to Metease Payioa

|0379| As described above with 'respect to met od 1800 and 2600, the UAV may operate m a, delivery mode to deliver a payioad to a. target location and subsequently operate in a release-verification, mode to verif that the payioad has separated from the payioad coupling apparatus. However, there r y be sitaaiioas in whic the payioad does not separate from the payioad eonpliag apparatus, upoa delivery. For instance, the payioad coupling: apparatus may become snagged ^' on the payioad such that when, the UAV motor Is operated to caus over-r n of the tether,, liie pa ioad coupling apparatus reasaias coupled to the paytead father than io eria and deiaehing fro the payioad. Accordingly, the oo-n rol system may detect such a situation and respoosively take remedial action by causing the tether to detach from the UAV rather thaa causing the payioad to detach ftom the payioad coupling apparatus,

(03711 Figure 34 is a. flow chart Illustrating a .method 340 for detaching a tether from, a UAV. Method 3401 ⁾ may he carried out by a U V s«eh as those described elsewhere herein. For example, method 3400 may he carried out by a control system oft UAV ^' with a winch system. Further, the winch sysieai may include a tether disposed oa a spool, a motor operable in a first mode and a secon mode that respectively counter and assist nnwinding of te tether due to gravity {e.g., b driving: the: spool forward or in reverse), a payioad coupling apparatus that mechanically couples the tether to a payioad, and a payioad latch swite able between closed position that prevents the payioad from, being lowered from the UAV and an open, position that allows the -payioad to fee lowered, from the DAY.

|f 72| As shows by block 3402, method 34(K3 involves die control systgrn of the

UAV operating the ^' mrotor to unwind the tether and lower the payioad toward the ground (e.g... by performing method .1800). Trie control system may be coafiguied to detect whe the pay load coniaets the ground and responsfvely initiate a tether over-run process to atteshpi t release the payioad from the payioad eonpiing apparatus, as shown b block 3404, Tether over-run occurs when the motor coutm es to on b the tether afte rhe payioad has siopped lowering. aring- tether over-run, the payioad: coupling apparabis continues to lower as tir tetbe is .un.wo.ond, white flie payioad remains stationary. This can cause tiie payioad coupling apparatus to detach from the payioad _* lor inst nce;, when the payioad is resting on a protruding arm or otter hook-like mec anism of the payioad coupling apparatus. As described above with respect to m thod 1 Θ, the control system ma detect when, the payioad contacts ti ground by monitoring speed and or a current of the motor and deiemhnhig that the .ii rtoi' speed aud/or motor current is th eshold low. As ftn-ther described above with, respect to aieihod 1.800, iaitiating tire tetber over-rua process -may involve operating the motor m the second mode to forward drive the spool is a- direction that causes the tetber to conti ue to un ind even -after the payioa ^' has reached, the ground.

f0373| Typically, carrying- ut the tether over-run- process - would: cause the payioad coupling apparatus to detach from the payioad,. However, ia situations where the payioa does not release ftorn t e payioad couplin apparatus, tire tether, over-rua process may be repeatahle u to a predetermined nutnbc of times, as further- shown by block 3404, f 03741 I» practice, once the payioad bas -reached, the ground and the control system has carried out a first tether- over-run process to attempt to separate the payioad coupling apparatus fr m the payioad, the contr l system ay deterrrbne whether the .payioad coupling apparatus bas actually separated f m the payioad, based ^' on &e current -of the motor (e.g., by performing hioefcs 2602 and 2604 of method 2600). For example, after operating the motor to cause tetber over-run,, the -control system may operate (he motor to begin retracting- tire tetber, and if the payioad is still attached to the payioad coupling apparatus, the extra weight of the payioad may cause the motor to draw more current Accordingly, the contro l sy stem may determine that die payioad is still attached to the payioad coupling apparatus b detecting that the motor cnnrsRt is: threshold high.

10375} Responsive to ^' making such a determination, the CGntrol system may repeat the processes- of lowering the payioad to the ground, operating the Motor to cause, over-run of the tether (this time, perhaps, by some predetermined additional length), and then pulling upwards on the tether to test for payioad separations shown in blocks 34t 2 and 3464, These processes may be .repeated a nui er of times until the control system, detemiines that the ^■ pay load has separated froiia the payload coupling apparatus w nftfil a threshold niimfecr of repetiiioas has occurred, as shown by block 3404.

}0376 The cemtroi system: may track how Hiatty times the. processes of causing over- ttrn of the tether and testing for payload separation have been carried oui arid may determine that these processes have bee repeated a threshold number of times without .successfully releasing the payload from, the payload coupling apparatus, as shown by block 3406. Responsive to making this determination, the control system .may decide to abandon fktiher attempts to separate the payload from the payload coupling a parahrs and may instead decide to separate the tether front the UAV by operating the otor to allow the teiher to unwind during ascent of the UAV, as showstfay ck 34$ B,

|iJ3?7 hi practice, the control system may operate the motor to allow the tether to unwind fey controlling a maximum current supplied to the motor. By limi ing the maximum current supplied to the motor, the control system limits the amount of force that the motor ears exert OR the tether. More specifically, the control system may limit the raaxi em earrent to a smali enough value that the motor s maximum upward force exerted on the tether is smaller is magaitwde than the downward fbree on the tether due to graxdtational ibrees on the payload. As a tesult, the UAV ay upward, and the tether wHl continue to trawiid due to the downward: force on the tether exceeding the upwar ftrce from the motor, i . other examples, the control system may merely tarn off the aiotor, allowing it to spin, freely, order Co obtain: similar results .

|iS3"?8 Further, as noted, above, the tether may be disposed on a spool More specifically , a first end of the tether ma be non-fixedly wound on the spool. As such, when the tether completel unwinds from the spool, the tether may detach and fall away from the spool. Thus, while the control system operates the motor to allow the tether t irawiad, the ^• coatrol system ma farther- cause the .11 AV to initiate a flight to a different location le.g,, a return, locatios), such, that the flight of ^'' the UAV unwinds the tether and separates the tether from the spool, thereb releasing the tether from the UAV, as sho a by block 3 10, In this manner, when the payload coupling apparatus is unable to detach from the payload, both the payload. and the tether may fee left behind at the delivery location, allowing the UAV to safely navigate away,

. Smg Detection

|0379| A UAV carrying out tethered ptektsp arte- delivery of payloads accordin to the processes disclosed herein may find itself operating in various different types of eaviroairtents with various diflererit issues to address. One issue ma n olve undesirable or unexpected forces exerted OH the teiher. For mstanee, a pstsoa may excessively yank on die letter, or the tether might get snagpd on a-■moving of statioaary object, resultin ¾ a downward force on die tether. Other examples are possible a well. Ift these sitnariotis, if .the d wnward force is great enough, the UAV cotid be pidied oui of its flight; perhaps damaging the UAV, die payload, or nearby e sons or -property. Accordingly... the control system may detect when certain forces are applied to the tethe during delivery of a payload. and responsively t ke reme ial action by allowing me tether to t wiad from, its spool.

Figure 35 is a. flow chart illustrating method 3500 of detecting and addressing midesirahie downward forces Oft a tether when lowering a payload toward the ground. Method 35 0: ¾ be -carried, out by a Ό AV- such as those described elsewhere herein.. For example, method 35CM May be carried oat by a control s stem of a DAY wi th a winch system. Further, the which system may nielude a tether disposed on a spool, a moto operable in a first mode and a. second mode that respectively counter and assist unwinding of the tether dye to gravity (e>g. _i: by drkiag the spool forward or in reverse), a payload conplin apparatus tb:at mechanieaOy eonp!es the tether to a payload, and a payload latch switehabie between a closed position that prevents die payload from, being lowered, f om the OA V an an open position that allows the payload to be lowered from the UAV.

( 3$I| As shown by block 3502, method 3501 ⁾ involves the control system of the UAV operating die motor to carry out tethered, delivery Of a payload: (e.g,, by per&rnilng method 1800). Paring the process: of delivering die payload to a target location, the control system may detect an undesirable downw rd.- feree oa the tether As described above,, the presence o f additional weight (or iit litis case, the presence of a sufficient do wnward force) on die tether may result in hierease in. current supplied to the mo tor in order to maintain a desired rotational speed of the motor. As such, the control system ma detect an undesirable downward force on the tether based on the motor current. Further, m order to avoid false positives, the control, system may also consider how long the motor current is increased. j¾382|. Additionally, the control system may consider an unwound length of the tether when detecting an undesirabl dowaward force. Fo instance, in order to limit the detection of downward forces to sources at or near gronrsd level (e.g., detecting a person yanking on tile tether), tile control system may also determine bow far the tether has been unwound from the spool in order to determine whether any part of .the tether is at or near ground level. Other examples are possible as weiL

fi)383| l¾ns, in ractice, during the process of delivering the payload to a target: location a¾d while the OA V is in flight, the control system may deiemiine an unwound length of the tether based on encoder data representisg a rotation of the tether spool, and the control .s stem may determine a motor current based on a current sensor of the motor or the power system of the 0AV\ Farther, the control system ma deierrnine that both (a) the unwound length of tether is greate than a threshold length and (b| the rooter current of die motor is greater tbas a threshold ciirtent, for at least a predetermined thmebu period, as shown by Mock 3504. Responsive to making such a determination, the control system ma operate the motor to allow the tetber to unwind when the UA ascends (e _r .g,, _: as described, above with: respect to block 340 ? of etbod : Qf3), as shown by block 3506. And forfher responsive to niaJsing the deterftiination, the eoatroi system may cause the tJA to tuiiia e a i ighi to a different location {e,g:„. a retimi loeahou), such that .the light of ^" the liAV un inds die tether and separates die tetber from me spool, mereby releasing tbe tether from the UAY, as shown by block 3508. this manner, when an undesirable downward force is exerted on the tether, the tether may unwind, and detach from tbe UAV, allowing the UA to safely navigate away, f 0384} In other examples, rather than detecting a snag and tes orisively operating the motor to unwind and release the tether, nags ma be resol ed by imposing a current limit on die motor when picking up a payload. liaiu sg the motor current to a maximum value limits die amount of force tbe motor can exert ό» the tether, which may prevent a UAV from crashing if the tether becomes snagged,- For instance _* if the ciirreni l mit is !ow enough that the nmximura upward force exerted on tbe tether by the motor is weaker than a downward force on the tetber,. then tbe current limit on the motor may allow the tether to completely unwind and detach fro its spool , ^■ should the UAV fly awa while the tetber is snagged. |0385f in addition to experiencing undesirable forces during delivery of a payload, the tether may also experience undesirable forces during pickup of the pay load,. For instance, ^• when winching a payload from the ground toward the UAV, the payload aad or the tetber may become snagged on various objects,; such as trees, buildings, or various other nearb objects. As another example, an unexpectedly .heavy payload could be attache to the tetber, resulting is an excessive downward force en the tenter that prevents the UAV from idling the payioad:. Accordingly, the control system may detect when certain forces; are applied to the tetber during picku of a payload. and responsively take remedial action.

|038is| Figure M is a flow chart illustrating a method 3600 of detecting and addressing undesirable downward forces on a. teihef when winching a payioad toward a UAV. Method 360(1 may he carried oat by a UA V such as those described elsewhere herei ,: For example, method 3600 may he carried ont by a control system of a UA V with a winch system. Further, the winch system, may include: a tether disposed o a spool, a moior urrwiud the tether and lower a payload coupling apparatus t au expected: payload attachment attitude, as shown by block 3704. As noted above, the payload attach ent aidtwde tmy be s altitude at which a human, or perhaps a robotic device:, may grab the pay load coupling apparatus for attaching the coupling apparatus to a payload. For instance, the pay load attachment altitude may be an altitude less than ttvo meters above ground level,

|93M} .Alter lowing t¾e tether, the control s stem may wait :&r a predetermined payload ^■ attachment period, as shown by block 3705. This attachment period allows time fer 3 human, or perhap a robotic device, to attach a payload to the payload coupling apparatus. J & Sj h the paylpad attachment period ends, the control s stem may perform an attachment yeriScafierj process _* as htrther showti by ^" block 37i ⁾ 6, Irs particular, the attachment ifkation process may involve the control system, operating the motor so as to counte unwinding of the tether for a predeterrnined -attachment verification period (e.g,, by pulling upwards on the tether in order to hold d e tether in place or retracting die -ether at a certain rate),, as shows by block .3706a, The- motor current required to hold llie tether in place or retract the tether at a certain rate will fee greater when the payload is attached, due to the added weight of the payload. As stick, the attachment verification rocess may further involve the control system detertn ugj based at least m part on motor cuweait during the ^• pcdeferftBaed ^' attaehaieat verification, period, whether or :«ot the payload eoxinKng apparatus i nieehanically coupled t the payload, as shown by Mock 3706b, For instance, as discussed above _* the .c n rol system may deternihie the motor current based on dat from a current sensor of the motor or of the power system of tne 11A¥, if during the attachment verification process, the motor -current exceeds a threshold, current value, t en: the control system may determine that the payload is eoitpied to the payload coupling apparatus. On the other hand, if the motor entreat is below the threshold current value, then the coatroi system may determine that the pay load couplin apparatus is n ot coupled to the pay load .

f03 | Further:, when the control system: detennines thai the payload coupling apparatus Is not mechanically coupled to the : pay loads the control system can ea»se the HAY to repeat the lowering of the: payload coupling apparatus and the attachment verification process in order to reattempt pickup of the payload, arid in some embodiments, these processes may onl he repeated up. to a predetermined number of times, _: as hown by block 3706, At this point rather titan attempting to pick up. the payload again, the coatroi system may cause the UAV to abandon the picku and navigate away, in practice, for instance, the eoatrol system may detqriaipe that the attachment verification rocess has been .repeated a predetermined nonihet of times without successful coupling of the payload euophng; app&fatas to the payioad, and responsively inrtiaie a i¾cess to ca«cel i kup of ^' the payioad and initiate tight Of the UAV to a next, different location^ as shown by ^' block 3708. lie dffiereni location may be another ptefciip location, or It may be some other location, such as a UAV dock for docking and/or storing the UAV. Other examples are possible as well |§397| As noted above, there ma fee smiation when control system falsely dermises that a payioad is attached during the payioad verification period, and the control: system may responsively cause ^' the motor to enter a winetnag state to retract the tether toward i e UAV. Accordingly, in order to .reduce such false det ^aa&ons _* . the duration of the ^• prete mitted attachment verification period described above ma b increased. Additionally or alternatively, the control system. My he farther configured to perform the attachment verification process and tether lowering process as shown by block: 3706 while operating in the winching state.

D. Payioa Latch Fsalnre

|Θ398| As described above with respect to method 1860, when a UAV suoeess&lly picks wp payioad and pulls the payioad or a payioad coepling apparatus into receptacle of the U V, the control system may close a payioad latch to secure the payioad to the UAV.. However, there may be sitaahons where the c ntrol system fails to close the latch (eg., due to m obstruction. Or softse ether issue) or where the control ^' system closes the latch but the close latch Sis to secure. &e. payioad to the UAV. Accordingly, the control system may be configured to determine whether the payioad latch has ceesshilly secured the payioad to the LAV

[0399 ¾* some embodiments, the eontro! system ma operate the motor to pull upwards an the tether prior to attempting to close the payioad lateh. If the payioad and/or payioad coupling apparatus have reached the UAV -receptacle, the payioad coupling apparatus is pressed -op against the U.AV such that ihe motor cannot retract the tether any fbr hef At ibis point,, closin the. payioad latch may successfully secure the payioad and/or the payioad co ling apparatus to the OAV, On the other hand, if the payioad and/or payioad cduplirj apparatus- have riot yet reached, the UAV reeeptacie, then the motor may still be retracting the tether, and. closing the payioad latch at this point: would, unsnceessi ily secure the; payioad. Accordingly,, when closing the payioad latch and/or -for a tirae duration after closing -t e payioad latch, th control system may be configured to monitor the motor speed to determine whether die payioad latch successfully closed and seenred the payioad to tbe UAV, or instance, reapons e to detecting that the motor speed is above a threshold speed. the■.control system may determine thai: the payload latch faSed to successfully close and/or secure the payload to the UAV.

jCMWf lh other eo odiments, after attctnptti g to close the payload latch _* rise ^■■ control system, may detect payload latch failure by operating the motor to unwind the tether a predetermined length. If the payload latch, was sueeessihlly elosed. to engage the payload or paylo ad coupling apparatus, then, ie payload or pay to d coupling, apparatus may be arranged within tie UAV receptacle snch that all or a portion: of the weight of the- payload rests oil the oay.load latch rather thai) the tether, and the motor current might be below a threshold current (e.g., appmxi a!ely zero). On the other hand, if the payload latch failed to close, then the weight of the payload might he si^p ied by the, tether, nd the motor current , repai ed to .support the weight of the payload aright be above a threshold current Accordingly, the coatroi system may deterrnise whether the payload latch successfully closed based on the motor current of tire UAV.

1 J In an ease,, responsive to ^■ detecting that ,the payload latc failed to close, the control system may operate . the motor to winc the payload hack toward the UAV and re tetnpt closing: the latch _* This process m b* repeated up to a predetermined xaimber of times o until the payload fetch is successfully closed. After tinsueeessfully repeating the process the ede m hsd number of times, the control ^■ system may responsiveiy operate the motor to lower the payload back t tile ground and detach the p&yfaad froitt the tether {e.g., by periorrnittg method; I BOO).

}f}4 2| The following table provides a brief representation of the various methods for detecting and resolv¾$ errors as described above.

Erro Detection Mechanism Responsive Action

^• Upoft delivery,, package gets Tether .overru - pt oeedure Turn off motor (or reduce stuck such thai it can't be ^■ attempted a tedetmrdiied motor current limit to lower released from payload .nu be of times without level) such thai tether coupling apparatus. ^' success. Kuwmds and eventually

detaches from spool, as U V flies upward aud or away.

Payload aad or payload Pa load re-lowedug and Enter the DESCBR ING coupling apparatus snag, winching back up attempted staie:3822 (see Figttr MB) during package pick-u (after predetermined -number -of of the delivery mode in order payload attached, while times withont success,. to return package to ground ^■ winching payload ¾p to at pkfctt location..

l.AV) ^: [Winching failure detected

when motor cwreat >

threshold AND uswouad

tethe length > threshold

(possibly after timeout

Other examples sre possible as wed. |0404f Oace the UAV re ches a. s urce location for pickup of a payload, the control system ma receive a corarasnd to pick up the payload and may responstvely edter a payload ptefcup, mode (e.g., by e forming method 1700 . As shown by state diagram .the payload pkk&p mode may include a LOWERING EIGOR state 3804, durin hich the control system operates the motor to u¾wm& the tether fernr a spook mid lower a payload couplin apparatus toward the ground.. While state 3804; refers to .the payload coupling apparatus as a hook, the payloa coupling apparatus cm take various f rms, as discussed above. The payload eouptiog apparatu may be lowered to a peedjstem ec! payload at&ehmerii altitude based on the altitude of the UAV, ©see the pay load eo«pSirig apparatus reaches the payload. attaehnjeht attitude (e.;g., w en the control sy tem: deter««0€S that the length of the unwoimd tether is at leas t .a threshold length), the coritrol system May cause the UAV to enter a WAITING FOR PAYLOAD stale 3806 for a time delay, during which the control system operates the motor to hold the payload coupling apparatus at a substantially constant altitude, thereby allowin th pay load to be attached, to t e pay load coupling i^paratus. Additionally, if the control system fails to determin that the payload coupling apparatus has been lowered to the predeterMined payload attachment altitude within a set time period e.g., a ^' timeout e iods the control system may responsively advance, to the WAfONG FOR PAYLOAD state 3806.

immi Fr m the WAITING FOE P YLOAD state 3806 _!: once the time delay elapses, the control system enters a VERIF ^" Ϊ PAYLOAD state 3808, During this state, the control system determines whether the payload is atiseked to the payload cotipiirig: ap aratus' based on a motor currest: supplied to the motor when the motor attempts to hold the payload coupling apparatus at a constant altitude or begins to retract the tether toward the UAV. If the mt current is below a threshold current during the VERIFY PAYLOAD state 3808, the control systetn returns to the ^' .LOWERING BOOK state 3804 to rearterapt. ttachment of the payload. As described above with respect to method 3700, this repetition may be repeated a tiumber of times wntil a limit is reached. Ouee the limit is reached,, the control system raay cause the UAV to retract the tether, ascend, and perhaps return to the IDLE state 3802 from which the AV may navigate to some other location.

10406} OR the othe hand, if disriug the VERIF PAYLOAD state 3808, the control system, deterniines that the payload ^" has been attached to the payload coupling apparatus (e.g., by detennitiing after a time delay that the motor current is at least a threshold current), the control system may enter S WINCHING .PAYLOAD ^' state 3810. Dtrrisg this state;, the control system may operate the motor to retract the tether and pall the payload toward the

Ψ7 UAV. As escribed above with respect to method 3700, the control system may also monitor motor Cttfretii in this- .state- 1¾ defefraiae -whether a f¾se positive was obtained .darh&g ^' the VERIFY PA.YLQAD: state 3808 (e ., by detecting that the motor c rrent is threshold low), Addilsoualiy, as rioted above with respect to method 360CL the control system may monitor the motor current during the WINCHING FA.YLQAD slate 3810 in order io _: detect wliea tiie tether becomes snagged: (e.g., by detecting: .that .the motor -camnt is threshold high). Responsive to deteetiag: a snag _s tbe control system may operate the. motor to lower the payload a predetermined length and reaftc- ipt winching the payload. After a threshold, number of attempts to remove tbe snag, the cornrol system may operate the motor to lower the payload to the: ground, and abandon pickup of the payload. This may involv advancing to a DESCENDrNG state 3822, which is discussed in more detail below*.

imm\ While operatin in the WINCHING EAYLQAD state 381 ( if no snags are detected, or if all detected snags are resolved, the control system ¾nay detect that the payload is within a threshold. distaftee of ilie PAY by measuri g a nisniber of r tations of the tether spool) arid responsively enter an. ENGAGI G PAYLOAD state 3812, During this slate, the control system may increase the c tteiii .supplied to the ftiotor for a pifcdeteimaed time period iu order t& attetnpi to pull the payioa - into, and orien the payloa within, s receptacle of the UAV. ¾ during this state, the control system detects that the motor current is -below a threshold etirrent Sfot that the tether is /ttowouad at least a threshold length, then the control system may responsiyeSy determfee that die payload is too far from the tl AV and may re-ester the lNCHJHG PAYLOAf) state 381 until the control system again detects that the payload is close enough to the UAV to ad ance to the ENGAGING PAYLOAD state 3812:,

104081 On the other hand, if, daring the ENGAGING PAYLOAD state 3812. the tiTOtor eurreni emai s threshold high and ihe unwound length of the tether indicates that the payload lias reached: die UAV, then die control system enters the LATCHING PAYLOAD state 3814, Owing thi state, the control system switches the payload latch to tbe closed position, thereby preventing the tether and/or the payioad front descending from the UAV. As described above, the control system ma determine whether the payload latch was snccessfuily closed by monitoring die motor speed and/or by operating the motor to attempt to lower the payload and monitoring the motor current, if ^' the. coatrol. system determines that the payload latch was not successfully closed, the eentfoi system ma return to the WiNCMlMG PAYLQAD state 3819 and. reatiempt to lift and engage the payload: Bnt if the control ystem determines that the payioad latch was saeeess&lly closed, then the control .s ste raay- ester a WAITING TO DELIVER state 3816.

}04» I The WAITIN TO DELIVER state 38 6 may fee similar to lite IDEE state

3802 where the payioad is secured to the UAY, and the control, system operates the motor to kee the payioad stationary. If, after a time delay, the coatrof system detects that the motor speed s .greater than a threshold speed, ihis ma indicate that ^' the payioad is not sufficiently secured to the II V, mi the control system rnay responsive!y retam to the MCIiMG f AAEOAD state 3810. Ot erwise, entering the WAiTING TO DELI ER state 3816 jagnals- the end of the picku mode .

J 418| While in the WAOTNG TO EtlVER. state 3816,. the control system mm receive co mand to deliver die payioad. and; may resportsively enter a deliver mode (e.g., by perfonnhig method 1800), The delivery mode may ineltide a PRl-DROP TEHSIO state 3-818. in this state, while the payioad latch is closed, the control, system may operate the motor to Kit the pay load (e.g., by setting the desired tether speed to t ra s or some oilier speed i -an upward direction, or by setting the motor current to a predetermined v hie^ thereby removin the weight of the payioad If cm the payioad latch w$ making it easier to open the payioad -latch.. While the PRE-DROP XEKSK state 3818, the control syste .may open the- payioad latch- and advance to tiie POST-DROP TEN I N state 3820 after -a tirne delay, ίιι this state, the control system asay operate the motor to hold th tethe in: a constant position for a _: predetermined, amonnt of time to allft the weight of the payioad to paii the pay load fi ml against the payioad coupling apparatws, thereby :t¾d«ci«g: any chance that the payioad might slip off and detach from the payioad conpilng a paratns. After the predetermined amount of time has passed, the control system may eater tile DESCENDING state 3822 , 1041.11 .In bo the PRE-DROP TENSION state 3:818 and the POST-DROP TENSION state 3820, if the control system detects that the payioad has traveled at least ^' s threshold distance (e,g., by measuring rotation of the spool), then, this m¾y indicate that arr error has occulted (e. ,, premature: detachment of the payioad fioin the payioad coupling ap aratus ^' or sna piag of the tether) because the spool -should /remain, substantially- moi-enfesk ■during these states, As a resviit to detecting such, art error, the control system may return to the IDLE state 3802 and cause the iJAV to navigate to a location where it may he serviced. f0412| -1» the DESCENDING state 3822, the control system may operate the -motor to unwind the tether according to a predeterarined. descent profile that specifies a constant or var in operationai speed of the motor Upon detecting that the tether has un ound at least, a predetermined amount (e.g., -detecting that the payioad is within a tiwesho distance of the j auBui based oa as altitude f the U V), the . control system may ^■ enter a WAITING FOR OUCHDOWN state 3824. & some exam les, the control syste may also be configured ro- advance from the DESCENDi G state 3822 to - the WAITING FOR OUCH OWN state 3824 if a threshold -amount of tim elapses in the DESCENDING state 3822 without advancing t the WAITING FOR TOUCHDOWN state 3824.

Ϊ0413Ϊ i the WAiXlNG FOR TOUCHDOWN ^' siaie 3824, the control system may

^• monitor tie oiotor currertt and its operational speed in- order to detect wSiether the payload has reached she ground, Spoci fica! iy, upon determmin that both the motor current and the motor speed are threshold , the control system y eater a POSSIBLE TOUCHDOWN state to verify that the payload has in fact: reached the gfo rod. The control system m fee configured to remai in lie POSSIBLE TOUCHDOWN state 3826 for predetermined amount of time. IT. during mat time, either the motor current or the motor speed becomes threshold high, this may -indicate that the paytoad lias not yet reached (he ground, and the ^■ control system may return to t e WAITING FOR TOUCHDO state 3824, Ho ever if, dnring the duratiosi of me POSSIBLE TOUCHDOWN state 3826, the motor eurrent atid ^' the motor speed remain tlwesnold tow, this may Indicate that i e payload has in fact reached tie gr und, aid the control system may responsiyeiy advance to a TOUCHED- DOWN state 3828. 1B some examples, the cosairol s st m may also be configured to advance from rise WAITING FO f OUCEDOWN state 3824 to th TOUCHED DOWN slate 3828 if a threshold amoaet of time elapses in the WAITING FOR TOUCHDOWN state 3824 without advancing t the ROSSI&LE TOUCHDOWN state 382o\

|0414J Once i the TOUCHED DOW sate 3828,. the control system may operate the motor to cause over-Rin of the tether such that the payload coupling apparatus continues to lower while the pay load remains stationar m the ground, Centintttng to l we tlie payload coupling apparatus .may cause the payload coupling ap ar tus to detach fto the payload. After causing tether over-run for a predetet med amount of time, die control system ma enter a VERIFY RELEASE state 3830 in order to determine whether the payload coupling apparatus did in fact separate from tlie payload,

J0 J ^' S| ^■ In the VERIFY RELEASE state 383 the control system .may operate the motor to pull upwards on the tether.; Based en the motor current when pulling upwards on the tether, die control system, ma determine whether or not the payload has been released from the payload coupling apparatus. If the motor current is threshold high, this may indicate that the payload is still, attached, and the control system ma reinm to the TOUCHED DOWN state 3828. This process may be repeated op to a predetermined number of times, at which point the eehtrol system ay enter a FREE SPIN state 3832.

|0416j o the FREE SPIN state 3832, the cortf.ro! system ma operate the motor to allow the tether to .completely (sti I such that th tether disconnects and falls awa from the IJAV. This may be achieved by limiting the -moior current to a sufficiently low value thai th moior is unable to counteract ike downward force o the tether caused by the gravitational pall on the iayloaxL Alternatively, the motor can: be shut off completely (e, _. g,,, limitin the motor current to 0 A),

0417f Referring back io tte VERIFY RELEASE state M, i£ tliroaghottt a pr^detemtined toaticsB, the motor enrrent remains threshold low, this may indicate that tie payload has in fact separated from the payload eoltp mg apparattrs. and the control system may respoBsively advance to aa ASGENFJIMQ state 3834,

(0418) ¾ the ASCENDING state 3834, the control system ma operate the motor to retract the tether and the payload coHpling: apparates up toward the WAV accordin to a predetermined ascent .profile that specifies constant or varying operational speed of the Motor,, Once the eotttrol system deteroiines that . ituwouBd: lengt of the tether is below a threshold length such that, the payload coupling apparatus is su Beierttiy close to the UAV ^' (e.g, _? based on a tiseas ireil msmber of rotations o f the spool), the control system, may enter ASCENDING PAUSE state &.

{94t to the ASCENDING PAUSE state 3B36, the control system, ma operate the motor to halt the refraction Of the tether. Once retraction of the tether i$ ^; halted, the eoBtroi system may control a movemeBt of the UAV in order to dampen any oseiilatioas of the tether that may have occurred drrrin the ASCENDING state 3834. After damping the tether oscillations, the control system may -eoSer a .FINAL- ASCENT state 83 .

| 20| to t e FINAL ASCENT state 3836, the control system may operate the motor to resettle retracting the tether. Ho ever^ is this state, the tether mav he retracted at a slower rate than that of the ASCENDING state 3834. This slower rate may introduce weaker scillations on the tether. Also daring rise FINAL ASCEN state 836. tile control system may moaitor the motor etirreB to determine wfien the payload coupling apparatus reaches the UAV. in practice, when, trie payload. coupling apparatus reaches the UAV, the apparatus is pressed against the dAV, the moior speed drops to zero, and. tire motor current increases in an attempt to inc ease motor speed, Accordingly., the control system. may determine that the payload coupling apparatus has reached the tiAV based n the motor eitrrent exeee iBg a threshold, entreat. Res onsiveiy, the coairol. system, may enter an ENGAGING state 384ft,

1.01 [ 4211 lift the ENGAGING- state 3-840, the control system may increase the .m ximu motor current ½ order to allow the motor to pall the payload coupling apparatus into, and orient itself ithin, a receptacle of {lie 13 AY. Once the payload coupling apparatus is sec tired within the receptacle, the control system may return t& the IDLE state 3802. If, during the ENGAGING state 38 0, the motor current f ils below a threshold current,, .this may indicate that the payload coupling apparatus was not is fact near to the UAV, and the detected, increas in curre t was likely ea«sed by soi e hiiig else (e,g, a temporary sna of the tether}. In ch s. scenario, -the control system may revert hack to the FINAL ASCENT stale; 383

(04221 As shown by the state diagram 3800, once he control system driers the

ASCENDING state 383 , the control system, may repeatedly advance to the next state upou determining that a threshold amount of time has elapsed it out advancing states,

f§423 in sonic examples, Sower maximum current limit, may he imposed, on the

^' UAV motor when retracting; the tether, as shown by states 3834 to 3840, when compared to lowering the tether, as shown by. states 3818 to 3828, This is because the tether is more likely to encounte a snag when retracting the tether, imposing a lower current limit reduces the amount of force that the motor ros exert ø»- the tether. This may prevent the motor from -causing the UAV to crash by continuing to inch: the UAV toward a snag;. And as: noted above, if the current limit is few enough that the maxismtnr ^' force of the motor is weaker than a downward force on the tether, then the -current limit on the motor ma allow ¹ the tether to completely unwind and detach from its spool shoud the (JAV away while the tether is snagged. Similar methods may he -empl yed, when initially picking up a payioad during states 3806 to 3814.

XIV, Additional Aspects

(Θ42 J In some embodiments, the control system of the U ^' AV may he configured to calibrate the rotary encoder and. speed ^'■ controller of the motor upon startup of the system. In practice, when the I A system is initially powered an, fhe motor should he stationary. Accordingly, tile encoder data should also indicate that the motor is- stationary , if the encoder data indicates otherwise, then an offset may he applied to the encoder data to account: lor any inconsistencies.

(04251 Tne control system may .hirthet test the frictioii of the moto ou startup of the

U ^' AV system. Based on the measured motor friction, an offset ma be applied to various ^• m tor current settings to account for the measured motor friction. Ove time, the friction of a DC motor may vary. Therefore, measuring friction on every startup and adjusting motor current settings- accordingly may enable consistent operation, o ver the life of the motor.

1.02 XV·.. Conclusion

}Θ426 'Die parhctilar arraligeaneats sfcows in the Figures .should not be viewed as limiting.: It should be nfsdeistood thai oilier iiripieffiesitstiGBS hia nclude more or less of each element shown in a given Figure, Fisrther, same of the Ilhistrated: elements y be combined or omitted. Yet fefiber, as exemplar implementation may include elements that are not illustrated m the Figures,

[Milj Additionally:, while varioas aspects and implementations have been disclosed herein, other aspects mud implementation will be apparent to those skilled in the art. The varions aspects and im^ mxt m& disclosed herein are i r purposes of illustration and are ■ ^■ apt intei¾<3e i -to be limitingi with the tee scope and spirit being indicated by the following claims. Other imple efttatioas ma he utilised, arid other ehaages may be m de, without departing frotn tlie spirit or scope of the subject ^■ shatter presented herein, it will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated hi the figures, can be aitfaaged* swbstiniied., eomljirted, separated;, an designed m . wide variety of different configurations, all of which are contemp lated herein.