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Title:
ACTIVE DOCKING STATION FOR HIGH-RELIABILITY LANDING AND STORAGE OF UAVS
Document Type and Number:
WIPO Patent Application WO/2020/181329
Kind Code:
A1
Abstract:
An active docking station enables improved operation of Unmanned Aerial Vehicles (UAVs). The docking station comprises: a base structure which secures the station to a mounting location; a robotic motion system connected to the base structure; a capture mechanism connected to the robotic motion system, where the robotic motion system moves the capture mechanism in at least two dimensions to first capture a UAV and then reposition a captured UAV relative to the base structure; and at least one of: an electrical connection for recharging electric UAVs, a mechanism for replacing batteries of electric UAVs, or pumps and mechanisms for refuelling UAVs with consumable fuel such as liquids or pressurised gases.

Inventors:
LAMB IAN CONWAY (AU)
Application Number:
AU2020/050228
Publication Date:
September 17, 2020
Filing Date:
March 12, 2020
Export Citation:
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Assignee:
LAMB IAN CONWAY (AU)
International Classes:
B64F1/22; B64C39/00; B64F3/00; G01S17/86
Foreign References:
US20090314883A12009-12-24
US20060249622A12006-11-09
US20180141680A12018-05-24
US10112712B12018-10-30
US9139310B12015-09-22
US9718564B12017-08-01
EP2241416A12010-10-20
US20170313421A12017-11-02
Attorney, Agent or Firm:
SPRUSON & FERGUSON (AU)
Download PDF:
Claims:
CLAIMS

What is claimed is:

1. An active docking station comprising:

a base structure which secures the station to a mounting location;

a robotic motion system connected to the base structure;

a capture mechanism connected to the robotic motion system, where the robotic motion system moves the capture mechanism in at least two dimensions to first capture an Unmanned Aerial Vehicle (UAV) and then reposition a captured UAV relative to the base structure; and

at least one of:

• an electrical connection for recharging electric UAVs;

• a mechanism for replacing batteries of electric UAVs; or

• pumps and mechanisms for refuelling UAVs with consumable fuel such as liquids or pressurised gases.

2. The active docking station of claim 1 , wherein the robotic motion system comprises: a plurality of arms that move the capture mechanism in approximately a single plane; or

a plurality of arms that move the capture mechanism in three dimensions.

3. The active docking station of claim 2, wherein the robotic motion system comprises a delta robot.

4. The active docking station of claim 1 , wherein the capture mechanism comprises a

positive-engagement mechanism to positively lock with a landing attachment on a UAV.

5. The active docking station of claim 4, wherein the positive engagement mechanism

includes a reduced air-pressure system or“vacuum” system to assist with the capture of a UAV.

6. The active docking station of claim 1 , wherein the robotic motion system further

comprises additional axes of motion to orient the capture mechanism to align with an orientation of a landing attachment on a UAV.

7. The active docking station of claim 1 , wherein the capture mechanism further comprises electrical connections which mate with electrical connections on a landing attachment on a UAV, and a power supply which can supply power through an electrical connection to charge a UAV parked in the docking station.

8. The active docking station of claim 2, further comprising a plurality of battery- replacement-mechanisms, which can each remove a battery from a UAV or put a battery into a UAV, after the robotic motion system aligns a UAV with a battery-replacement- mechanism.

9. The active docking station of claim 1 , further comprising sensors for precisely estimating the position, orientation, velocity and or angular velocity of the UAV relative to the base structure or the capture mechanism or both.

10. The active docking station of claim 9, wherein the sensors used for estimating the

position, orientation, velocity and angular velocity comprise one or a plurality of camera sensors, with one or more pairs arranged side-by-side in a stereoscopic configuration.

11. The active docking station of claim 9, further comprising one or a plurality of reflectors or retroreflectors on a bottom of a UAV to aid identification and accurate position, orientation and velocity estimations.

12. The active docking station of claim 1 , further comprising an opening and closing

enclosure mechanism connected to the base structure, which covers a UAV while closed, protecting a UAV from adverse weather conditions, and provides clearance for a UAV while open, allowing take-off and landing via the capture mechanism.

13. The active docking station of claim 12, wherein the capture mechanism is extendible outward from the enclosure mechanism via movement of the robotic motion system while the enclosure mechanism is open.

14. The active docking station of claim 12, wherein the enclosure mechanism comprises two “clamshell” halves that are hinged together and separable down a midline.

15. The active docking station of claim 12, wherein the enclosure mechanism comprises at least one panel connected to the base structure by a 4-bar linkage.

16. The active docking station of claim 12, wherein the enclosure mechanism includes

transparent windows for viewing a UAV from outside, and enabling the operation of a UAV’s visual and thermal sensors to sense an external environment while the enclosure mechanism is closed.

17. The active docking station of claim 12, further comprising a climate system connected to the base structure to humidify or dehumidify air inside the enclosure mechanism, or to replace or flush air inside the enclosure mechanism.

18. The active docking station of claim 1 , further comprising an internal battery in the

docking station which can be recharged using a solar energy system, wind energy system, or other non-persistent energy sources.

19. The active docking station of either claim 12 or 18, further comprising an array of solar panels on an outside surface of the enclosure mechanism which can be used to charge an internal battery.

20. The active docking station of claim 1 , further comprising a system for washing a UAV using fans, pressurised air or water jets, while it is held by the capture mechanism.

21. The active docking station of claim 1 , wherein the capture mechanism comprises a chuck-like mechanism to capture, using a clamping motion while rotating, a rotating UAV with a protruding spike on a lower side.

Description:
TITLE

Active Docking Station for High-Reliability Landing and Storage of UAVs

FIELD OF THE DISCLOSURE

The present invention relates generally to ground-based robotics for launching, “socking” ( e.g landing and storing), recharging or refuelling unmanned aerial vehicles, and robotic tracking mechanisms and control systems, some or all of which may be releasably contained inside weather-proof or weather-resistant enclosures.

BACKGROUND

The technology of unmanned aerial vehicles (UAVs)— often referred to as remotely piloted aircraft systems (RPAS), unmanned aerial systems (UAS) or drones— is becoming commercially widespread. The architecture and design of such vehicles varies greatly from large scale UAVs armed with weapons, which have been deployed in combat zones, to medium-sized aerial reconnaissance drones used both commercially and recreationally. In addition, very small-scale UAVs have been manufactured and sold as toys.

While manually-controlled UAVs have a variety of practical uses, it is becoming increasingly desirable to automate UAV operations, particularly in commercial applications. Most commercial applications of UAVs rely on operators being on-site to control, or at least monitor, each UAV. However, some UAVs have been configured to autonomously perform some actions, such as take-off, landing, and other flight operations, with minimal human interaction. Despite these steps toward automating UAV flight, it is often the case that a human performs the UAV setup, installs the battery, runs pre-flight checks, and recharges or replaces the battery before each flight. As a result, substantial human intervention is typically required to perform a complete end-to-end UAV operation, even when many aspects of the UAV’s flight are accomplished autonomously.

One example of an application involving automation of a large number of UAVs is UAV package delivery. Some existing UAVs have been used as part of the delivery method for items purchased from retailers. These UAVs may take off from and land at handling facility buildings, on delivery vehicles, or at other stationary locations. To overcome the limitations of UAVs requiring on-site operators, some UAV systems have taken steps to automate aspects of the launch, performance of a mission, landing, recharging, refuelling, or swapping of batteries, and uploading data to a server, without substantial intervention by an onsite operator. These UAV systems typically include one or more of the following: a platform from which the UAV can take-off and land; a roof or wall which opens to allow passage of the UAV from an indoor space to an outdoor space; a communications system to control and receive telemetry and data from the UAV, as well as to remotely monitor and control the UAV through an external network, such as the Internet; and some means for restoring the UAV’s depleted energy source. In some cases, robotic systems have been provided that attempt to align the grounded UAV to an automated battery swapping, refuelling, or battery charging station— each of which are often outfitted with an array of connectors, nozzles, or the like to enable the energy restoration of the UAV without requiring precise positioning. Typically, these automated systems rely on the UAV navigating precisely onto a landing platform, either using onboard vision systems, ultrasounds, differential GPS or RTK positioning.

In attempting to automate the post-landing activities for readying a UAV for a subsequent flight, various UAV“base stations” have been proposed. One proposed solution involves providing a base station that is itself capable of replacing UAV batteries. Another proposed solution includes the provision of a“docking station,” which can autonomously recharge the UAV’s batteries, refuel the UAV, or exchange the UAV’s current batteries for a different battery or battery pack ( e.g ., to extend the range of UAVs during package delivery.

Some proposed solutions provide for specific types of passive landing mechanisms, which help guide a landing UAV toward a more precise landing location. In one instance, the integration of a “conical stopper” onto a UAV has been proposed, which couples with corresponding conical indentations on a landing platform. Another proposed mechanism utilizes three V-shaped guides to align the UAV to a specific position on landing.

Active systems have also been proposed to align a UAV after it has landed on a platform, which attempt to engage one or more structural components of the UAV as it descends toward a landing platform. For example, one proposed solution involves providing a dangling wire from the UAV, which is pulled toward the docking station using an electromagnet or a winch.

However, the above-described passive and active docking stations have a number of drawbacks and limitations, which have prevented widespread adoption. For example, these systems may not be perfectly reliable even under ideal conditions. Existing solutions do not address the problem of performing an autonomous landing of UAVs under adverse weather conditions, such as strong or gusty winds during landing which generate unexpected movement or drift in the UAV. A common way to account for such unexpected motion during landing is to provide a landing platform or basic passive guides that are much larger than the UAV itself, to effectively increase the size of the landing zone. However, large platforms and guides are often insufficiently robust to guarantee a successful landing, depending on the severity of the winds and other weather conditions. In addition, providing large platforms can have the undesirable effect of increasing the overall size of the landing system, which may be unsuitable for certain applications or prohibitively increase the cost of the system.

Moreover, passive landing mechanisms alone are often unable to reliably capture a landing UAV under poor weather conditions. While the inclusion of such passive landing mechanisms can reduce the overall size of the docking station, the UAV itself may have to be configured with a substantially precise control system, to enable the UAV to land accurately onto the passive landing mechanism. Although the docking system may decrease in cost and complexity, the UAV itself may grow in cost and complexity.

SUMMARY OF THE DISCLOSURE

Described herein is technology for, among other things, providing a robust, reliable, and fully automated UAV and docking station system capable of launching, landing, recharging or replacing batteries or refuelling— all under a variety of weather conditions. As the UAV and docking station system may be subject to adverse weather conditions such as wind, precipitation and spray, as well as dust, various embodiments also provide an enclosure system that protects the UAV and/or docking station components from undesirable weather. Advantageously, such a robust UAV and docking station system would improve factory automation, reduce labour costs through automation, increase the regularity of operations with UAVs working around the clock, and improve safety by removing human workers from dangerous environments.

These and other objectives and advantages of the present invention will become apparent from the following detailed written description, drawing figures, and claims.

To accomplish the aforementioned objectives, embodiments of the present application provide for launch and retrieval systems for UAVs. An active docking station, or launch and retrieval system, may include a base structure with movable enclosure sections that can surround components contained within the active docking station. A robotic motion system may include an articulated robotic arm, which has attached thereto at its distal end a capture mechanism that is adapted to mate with a corresponding component extending beneath a UAV. The robotic motion system may include cameras, sensors, and/or other components thereon which are used to determine the location and distance of the UAV from the active docking station. As the UAV descends for landing, a tracking system running on a processor of the active docking station 100 may cause the articulated robotic arm to continuously maintain substantial vertical alignment with the UAV. Once docked, the UAV may undergo one or more post-landing procedures, such as recharging or replacing the UAV’s batteries, refueling the UAV’s energy source, or storage of the UAV within the enclosed active docking station, among other possible post-landing procedures).

Advantageously, the active docking stations described herein permit a higher wind tolerance, gust tolerance and turbulence tolerance during landing, due to the active motion control of the capture mechanism which can compensate for unpredictable UAV motion in windy, gusty and turbulent conditions, and due to the positive capture mechanism to secure the UAV during landing, prior to the UAV reducing power, ensuring a more reliable landing, particularly in strong and gusty winds. Additionally, the overall dimensions of the active docking station may be reduced compared to other docking stations for a given size of UAV, since the enclosure can be designed to be slightly larger than the overall dimensions of the UAV contained inside, rather than providing a large landing platform as described above. Furthermore, many general-purpose landing gear components that might otherwise be included can be removed from the UAV, and replaced by a landing attachment which is smaller, lighter, and less obtrusive than general-purpose landing gear. In some cases, an integrated electrical connection in the capture mechanism can be used to recharge the UAVs’ batteries, without the need for additional mechanisms for alignment or positioning of the UAV.

According to one aspect, the invention is defined as an active docking station comprising: a base structure which secures the station to a mounting location;

a robotic motion system connected to the base structure;

a capture mechanism connected to the robotic motion system, where the robotic motion system moves the capture mechanism in at least two dimensions to first capture an Unmanned Aerial Vehicle (UAV) and then reposition a captured UAV relative to the base structure; and

at least one of:

• an electrical connection for recharging electric UAVs;

• a mechanism for replacing batteries of electric UAVs; or

• pumps and mechanisms for refuelling UAVs with consumable fuel such as liquids or pressurised gases. Preferably, the robotic motion system comprises: a plurality of arms that move the capture mechanism in approximately a single plane; or a plurality of arms that move the capture mechanism in three dimensions.

Preferably, the robotic motion system comprises a delta robot.

Preferably, the capture mechanism comprises a positive-engagement mechanism to positively lock with a landing attachment on a UAV.

Preferably, the positive engagement mechanism includes a reduced air-pressure system or“vacuum” system to assist with the capture of a UAV.

Preferably, the robotic motion system further comprises additional axes of motion to orient the capture mechanism to align with an orientation of a landing attachment on a UAV.

Preferably, the capture mechanism further comprises electrical connections which mate with electrical connections on a landing attachment on a UAV, and a power supply which can supply power through an electrical connection to charge a UAV parked in the docking station.

Preferably, the docking station further comprises a plurality of battery-replacement- mechanisms, which can each remove a battery from a UAV or put a battery into a UAV, after the robotic motion system aligns a UAV with a battery-replacement-mechanism.

Preferably, the docking station further comprises sensors for precisely estimating the position, orientation, velocity and or angular velocity of the UAV relative to the base structure or the capture mechanism or both.

Preferably, the sensors used for estimating the position, orientation, velocity and angular velocity comprise one or a plurality of camera sensors, with one or more pairs arranged side-by-side in a stereoscopic configuration.

Preferably, the docking station further comprises one or a plurality of reflectors or retroreflectors on a bottom of a UAV to aid identification and accurate position, orientation and velocity estimations.

Preferably, the docking station further comprises an opening and closing enclosure mechanism connected to the base structure, which covers a UAV while closed, protecting a UAV from adverse weather conditions, and provides clearance for a UAV while open, allowing take-off and landing via the capture mechanism. Preferably, the capture mechanism is extendible outward from the enclosure mechanism via movement of the robotic motion system while the enclosure mechanism is open.

Preferably, the enclosure mechanism comprises two“clamshell” halves that are hinged together and separable down a midline.

Preferably, the enclosure mechanism comprises at least one panel connected to the base structure by a 4-bar linkage.

Preferably, the enclosure mechanism includes transparent windows for viewing a UAV from outside, and enabling the operation of a UAV’s visual and thermal sensors to sense an external environment while the enclosure mechanism is closed.

Preferably, the docking station further comprises a climate system connected to the base structure to humidify or dehumidify air inside the enclosure mechanism, or to replace or flush air inside the enclosure mechanism.

Preferably, the docking station further comprises an internal battery in the docking station which can be recharged using a solar energy system, wind energy system, or other non-persistent energy sources.

Preferably, the docking station further comprises an array of solar panels on an outside surface of the enclosure mechanism which can be used to charge an internal battery.

Preferably, the docking station further comprises a system for washing a UAV using fans, pressurised air or water jets, while it is held by the capture mechanism.

Preferably, the capture mechanism comprises a chuck-like mechanism to capture, using a clamping motion while rotating, a rotating UAV with a protruding spike on a lower side.

The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments and features will become apparent by reference to the drawing figures, the following detailed description, and the claims. BRIEF DESCRIPTION OF THE DRAWINGS

To assist in understanding the disclosure, and to show how embodiments of the present application may be implemented, there will now be described by way of example specific embodiments, apparatuses, systems, and methods with reference to the accompanying drawings, in which:

FIG. 1 is an elevated side cutaway view of an active docking station in a closed configuration, with a UAV held in a central home position protected from weather, according to an embodiment of the present application;

FIG. 2 is a perspective side view of an active docking station in an open configuration, tracking a UAV for landing, according to an embodiment of the present application;

FIG. 3 is a detailed perspective view of the two stereoscopic optical tracking systems shown in FIG. 2, according to an embodiment of the present application;

FIGS. 4A and 4B are detailed cross-sectional side views of an example positive- engagement capture mechanism and corresponding mechanical attachment on the UAV, which are collectively operable to release and recapture the UAV, according to an embodiment of the present application;

FIG. 5 is a detailed top plan view of three battery replacement mechanisms, adjacent to the robotic motion system and capture mechanism, according to an embodiment of the present application;

FIGS. 6A and 6B are detailed perspective cutaway views of an alternative positive- engagement capture mechanism, adapted for the capturing of rotating UAVs configured with a protruding spike on the lower side using a rotating clamp or chuck to tightly clamp the spike of UAV, according to an embodiment of the present application;

FIG. 7 is a front cutaway view of an active docking station in a closed configuration, with a UAV held in a central home position protected from weather, according to an alternative embodiment of the present application;

FIG. 8 is a detailed close-up front view of an opening and closing enclosure mechanism which consists of a 4-bar linkage, according to the embodiment of FIG. 7; and

FIG. 9 is a partial-cutaway perspective side view of an active docking station in an open configuration, tracking a UAV for landing, according to the embodiment of FIG. 7. DETAILED DESCRIPTION

There will now be described by way of example, several specific modes of the invention as contemplated by the inventor. In the following description, numerous specific details are set forth in order to provide a thorough understanding. It will be apparent, however, that the present invention may be practiced without limitation to these specific details. In other instances, well known methods and structures have not been described in detail so as not to unnecessarily obscure the description of the invention.

In this patent specification, adjectives such as“first” and“second,”“left” and“right,” “port” and“starboard,”“top” and“bottom,”“upper” and“lower,”“rear,”“front” and“side,” and other relative or directional terms are used solely to distinguish one element or method step from another element or method step, without necessarily requiring a specific position or sequence that is described by the adjectives. Words such as“comprises” or“includes” are not used to define an exclusive set of elements or method steps. Rather, such words merely define a minimum set of elements or method steps included in a particular embodiment of the present invention.

Referring now to FIGS. 1 and 2, an active docking station 100 may be arranged in an open configuration (shown in FIG. 2) or a closed configuration (shown in FIG. 1). FIG. 2 illustrates an example operation, whereby a UAV 190 approaches the docking station 100 for landing toward a capture mechanism 150. The active docking station 100 includes a base structure 110. A robotic motion system 140 which may have two arms 145 and 146, connected by a joint to form a two degree-of-freedom (DOF) articulated robotic arm, which is attached to the base structure 1 10 at its proximal end, and is operable to move a capture mechanism 150 at its distal end. An enclosure system, which may have a left enclosure side 120 and a right enclosure side 130 rotatably affixed to the base structure 110. The active docking station 100 may be operable to tilt the left and right enclosure sides 120, 130 in opposite directions, so as to expose the robotic motion system 140 (referred to herein as an“open configuration”). Conversely, the left and right enclosure sides 120, 130 are movable toward each other, to form a shell that encapsulates the robotic motion system 140 and/or the UAV 190 (when docked with the capture mechanism 150) from the external environment.

As described in further detail below, the capture mechanism 150 is movable using the robotic motion system 140 to be in substantial alignment with the UAV 190 during a landing manoeuvre. The capture mechanism 150 is adapted to capture the UAV by mechanically connecting to a landing attachment 195 on the UAV 190. In an example embodiment, the robotic motion system 140 consists of a two-DOF controllable robotic arm, in which both arm segments 145, 146 rotate about axes which are aligned approximately vertically, such that the motion of each arm segment 145, 146 approximately lies in a horizontal plane. This robotic arm configuration, which may be referred to as a“SCARA robot,” reduces the load borne by the actuators from the weight of the robotic arm, the weight of the UAV 190, and/or the downward impulse that occurs when the UAV initially makes contact with the capture mechanism 150. Instead, the load is borne by the bearings, reducing the torque requirement of the actuators while simultaneously improving their reliability. Alternatively, according to some embodiments, the robotic motion system 140 may include an additional vertical axis of motion ( e.g ., through the addition of another arm segment). In other embodiments, the robotic motion system 140 may use an x-y positioning platform, a delta robot, a Stewart platform, or some combination of linear and/or rotary actuation devices to achieve two- or three-dimensional movement (with any number of DOFs) of the capture mechanism 150.

A tracking system, described in more detail below, may determine or estimate the position of the UAV 190, to enable the precise alignment of the capture mechanism 150 with a corresponding element of the UAV 190, such as landing attachment 195.

The base structure 1 10 may include components that secure the active docking station 100 to the ground or to a device on which the active docking station 100 can be mounted, such as a vehicle, building, wind turbine, oil-rig, or other structure.

The enclosure system, having a left enclosure side 120 and a right enclosure side 130, is shown in an open position in FIG. 2, and provides clearance for UAVs while in an open position, to allow for take-off and landing of UAVs. Windows 131 and 132 allow viewing of the UAV 190 while the system is closed, and also allow optical sensors the UAV 190— such as camera payloads, lidar, and gas sensors, to observe the external environment without opening the enclosure of the active docking station 100. Solar panels 130 may serve as a power source for recharging the docking station’s internal battery or batteries while the UAV 190 is flying or docked. The internal battery of active docking station 100 may recharge the battery or batteries onboard the UAV 190 when it has landed, or may recharge spare batteries at any time.

Referring now to FIG. 1 , FIG. 1 illustrates an elevated side cutaway view of an active docking station 100, with a UAV 190 held in a central home position, according to an embodiment of the present invention. The enclosure system of the active docking station 100 can be closed around the robotic motion system 140, the capture mechanism 150, and the UAV 190, after the UAV 190 has landed and has been moved to a stowing position, as shown in FIG. 1. The enclosure system protects the UAV 190 and robotic motion system 140 from adverse weather conditions such as wind, precipitation, spray, dust, and/or other weather conditions.

FIG. 3 is a close-up perspective view of a stereoscopic optical tracking system 300 of the active docking station 100, which may be used to track the UAV 190. In this embodiment, a pair of cameras forming a stereoscopic pair, 301 and 302, point upward to observe the UAV 190 as it approaches the docking station 100 from above. The stereo pair enables tracking software running on the active docking station 100 ( e.g ., using a processor, field- programmable gate array (FPGA), or another suitable computing device) to accurately determine the distance to the aircraft, especially when the size or configuration of the aircraft may not be precisely known. Cameras 301 and 302 may, together with a processing device, periodically generate depth maps, which may in turn be used to assess the location and distance of the UAV 190 in real time or near-real time. The location and distance of the UAV 190 with respect to the active docking station 100 may serve as a basis for controlling the robotic motion system 140, to align the capture mechanism 150 with the landing attachment 195 of the UAV 150 during a landing sequence.

In addition, lens-cleaning nozzles 310 may be provided, which may be coupled to a pressurised air system, either from a compressor or lightly pressurised by a fan, to expel jets of air to remove dust, raindrops and condensation from the top of the lenses of the cameras.

In some implementations, the UAV 190 may be equipped with Global Navigation Satellite System (GNSS) onboard. In these implementations, the UAV 190 may fly to a known GNSS-based position of the docking station 100, and at a particular altitude above it, when the UAV 190 descends for a landing. With the UAV 190 above and near the docking station 100, the tracking system of the active docking station 100 can detect the UAV 190, track it, and accurately guide it down to landing, even if the UAV 190 does not have a perfect estimate of its position.

In other implementations, both the docking station 100 and the UAV 190 each have their own GNSS, communication between the two allows for more accurate position estimation using differential GPS or RTK, which can then be fused with the position estimation from the tracking system. The UAV 190 may also use external sensors to detect its position relative to the docking station 100, such as downward facing cameras. To aid the UAV 190 in vision- based position estimation, recognizable patterns and colours may be painted or otherwise made visible on surfaces of the docking station 100 which are upward-facing in the open configuration and remain stationary while the robotic motion system 140 is moving. Additionally, the patterns may be coloured and/or shaped in a way that is easy for the tracking mechanism to differentiate them from the colour and shape of the moving parts, including the robotic arms 145, 146 and the capture mechanism 150.

When the UAV 190 is below a certain altitude, the robotic motion system 140 may continuously move the capture mechanism 150 along its horizontal plane of motion to maintain substantial vertical alignment with the landing attachment 195 on the UAV 190. This mitigates against any unexpected motion of the UAV 190 due to gusts, which can be compensated for by the robotic motion system 140 (which may have a comparatively greater acceleration and/or movement speed compared to the speed and acceleration of the UAV 190 during landing). At the end of the descent, the landing attachment 195 of the UAV 190 engages with the capture mechanism 150 on the docking station 100, which is shown in greater detail in FIGS. 4A and 4B.

In addition, estimating depth at very short distances can be difficult with some stereoscopic camera arrangements. When the UAV 190 is very close to the capture mechanism 150 ( e.g ., within some threshold distance away from the capture mechanism 150), the tracking software operating on the active docking station 100 may switch from a depth map mode to an object-tracking mode, which may not rely on depth information. In some embodiments, the tracking systems may incorporate a visual servoing configuration sometimes referred to as“eye-in-hand,” in which the camera or cameras are rigidly coupled to and move with the capture mechanism 150 on the robotic motion system 140— to enable the object-tracking mode operations. Additional or alternative sensors may be mounted further from the capture mechanism 150, such as on arm 146, which might use the eye-in-hand configuration due to the sensors being mounted on the same rigid body of robotic motion system 140. Such additional sensor arrangements may offer the advantage of maintaining a greater distance from the UAV 190 even in the final stages of landing, avoiding the problem of the UAV 190 moving to within a minimum depth-estimation distance of the sensor.

In other embodiments, an alternative“eye-to-hand” camera configuration may be used, which may involve mounting a camera on a stationary part of the docking station 100. In some cases, a combination of“eye-in-hand” and“eye-to-hand” configurations may be used with multiple cameras mounted on different portions of the active docking station 100.

In various embodiments, tracking systems of the active docking station 100 may integrate other sensors to track the UAV’s position, velocity, and orientation in 3D space, such as individual mono- and poly-chromatic cameras, infrared cameras, passive and active infrared sensors, ultrasound transceivers, and/or radar and lidar systems, among other possible sensors. Illuminators, either broadly illuminating with an even light distribution or projecting patterned light ( e.g infrared light), may be used to assist the position sensors in determining an accurate location and distance of the UAV 190.

FIG. 4A is a detailed cutaway view of an example positive-engagement capture mechanism 150, which may be used to release and recapture the UAV 190. In FIG. 4A, the landing attachment 195 is shown fully engaged with the capture mechanism 150. In FIG. 4B, the landing attachment 195 is shown in a state of partial engagement with the capture mechanism 150 (e.g., before landing or after take-off).

The capture mechanism 150 includes a positive-engagement mechanism which, during a landing manoeuvre, mechanically secures the UAV 190 to the active docking station 100, to ensure a more reliable landing, particularly in strong and gusty winds. Once the UAV 190 is fully engaged with the capture mechanism 150, the UAV 190 may reduce power or power down, more safely than in a system which does not feature a positive-engagement mechanism.

The example positive-engagement mechanism shown in FIGS. 4A and 4B includes a motor 420 that drives a gear 421 , which in turn drives gear nut 422, which in turn and moves the shaft 410 downward relative to tube 411 , forcing the balls 412 inwards and downwards. The balls may be sprung outward to ensure the landing attachment 195 enters the tube 411 without obstruction, or may otherwise move outwards as the landing attachment 195 enters the tube 411 with at least a threshold force. To avoid the balls 412 falling out when the UAV 190 exits the capture mechanism 150, the balls 412 may be retained by a slight narrowing of the holes in the tube 411 , and/or using separate retaining rings inside the tube which have holes with inner diameters that are slightly smaller than the in the inner diameter of holes of the tube 411. When the landing attachment is close to the fully engaged position the positive- engagement system is locked. The capture mechanism 150 is shown in the open position in FIG. 4B and in the locked position in FIG. 4A. The active latches provide a downward force which secures the UAV 190 and ensures a reliable electrical connection for charging. Shaft 410 can be hollow, as shown in FIGS. 4A and 4B, to allow water to drain out of the bottom of the system, so the capture mechanism 150 can suitably function in wet conditions, such as rain or sea-spray, without filling with water. Additionally, o-rings may be used to seal various components of the positive engagement mechanism, to extend the operation lifetime of the active docking station 100.

Various types of capture mechanisms, other than those explicitly shown and described herein, can be employed to positively capture the UAV 190, including active and passive mechanisms, ball-socket mechanisms, articulated grabbers, electromagnets and vacuum systems, among other possible capture mechanisms. Passive latches can act as a ratchet mechanism to allow the landing attachment 195 to move generally downward into the capture mechanism 150, but not generally upward, limiting the potential for the UAV 190 to bounce upward when wind is buffeting the UAV 190 up and down during descent. A vacuum pump system (not shown) may be attached to the hollow opening 430, and may be used to decrease the air pressure locally in and around the capture mechanism 150, creating a downward suction force on the landing attachment 195 and the UAV 190 when the landing attachment 195 is in close proximity to the capture mechanism 150. The vacuum pump system may limit the potential of the UAV 190 to bounce upward after approaching or making contact with the capture mechanism 150. In some embodiments, the exhaust of the vacuum pump system may be used to provide the air for the lens-cleaning nozzles 310, 31 1. A valve system may be used to allow the vacuum pump system to pump air through the hollow opening 430, while still allowing water to drain through the hollow opening 420.

In various embodiments, some combination of passive latching mechanisms, active latching mechanisms, and a vacuum pump system may be used to secure the UAV 190.

In alternative embodiments, the capture mechanism 150 may be mechanically passive, guiding the UAV 190 using a mechanical system such as the conical-shape capture mechanism, shown in FIGS. 4A and 4B in combination with an active positive-engagement mechanism. Such a passive capture mechanism may secure the UAV 190 and hold it upright after it lands, and may rely on the UAV 190 to adjust its attitude to the correct upright position before powering down, if necessary.

Concentric electrical contacts 440, 441 in the capture mechanism 150 may mate with concentric electrical contacts 450, 451 on the landing attachment 195, which can be used for charging the batteries onboard the UAV 190. Additional connections may be used for transmitting data to and from the UAV 190, in addition to or in place of standard wireless communication, particularly when the transmission of substantially large amounts of data quickly is desired.

FIG. 5 is a close-up top plan view of three battery-storage units, next to the robotic motion system 140 and capture mechanism 150. The robotic motion system 140 can position the UAV 190 to align with any of a plurality of battery-storage units, 501 , 502, 503, such that a battery-replacement mechanism can remove the UAV’s depleted battery and store it in any empty battery-storage unit, and may then insert a charged battery from any battery-storage unit into the UAV 190. There may be a battery-replacement mechanism attached to the capture mechanism 150, or there may be a battery-replacement mechanism in each battery storage unit, depending on the particular implementation. FIG. 5 shows a configuration where robotic motion system 140 has aligned the capture mechanism 150 with battery-storage unit 503. With a captured UAV in this position, the battery-replacement mechanism could add a battery to the UAV, or remove a battery from the UAV.

A simple example of a battery-replacement mechanism may include a single-DOF arm which can lift and lower a battery vertically into and from the UAV 190, while the robotic motion system vertically aligns the UAV 190 by moving it horizontally to a position in substantial vertical alignment with a replacement battery. A push-up-to-lock, push-up-to- unlock latching system for inserting and removing the battery from the UAV 190 may be used, which may beneficially reduce the number of total actuators used in implementing the battery- replacement mechanism. Alternatively, the UAV 190, the robotic motion system or the battery- replacement mechanism may include a small actuator which can mechanically and/or electrically secure a battery into the UAV 190 after the battery-replacement mechanism has lifted the battery into position, and mechanically and/or electrically remove a battery from the UAV 190 to in turn allow the battery-replacement mechanism to lower the battery. Alternatively, and/or additionally, the battery-replacement mechanism may have a 2-DOF arm which can lift and lower a replacement battery using one DOF, and can twist the battery to mechanically secure it into place or remove it from the UAV 190.

Like the battery-replacement mechanism, similar payload-replacing mechanisms may be used to replace payloads such as cameras or cargo. One advantage of replacing sensor payloads is that a UAV may perform multiple inspections with different payloads on different flights, rather than carrying multiple payloads on a single flight which can limit endurance or even can be impossible to configure. An example would be carrying a standard camera to perform a visual inspection to look for damage, and following up on a separate flight with a gas-sensing camera to look for gas-leaks. For package delivery, automated payload replacement can further reduce the necessary human interaction involved for UAVs delivering many packages, and the time saves can reduce the total number of UAVs required to deliver a number of packages in a certain time.

An advantage of replacing batteries, rather than recharging the battery on the UAV 190, is that the time between flights can be reduced. Additionally, when the docking station 100 and UAV 190 are used for very regular flights in remote locations, the battery may have the shortest lifespan of any component, and using multiple batteries can extend the time between replacing batteries. FIGS. 6A and 6B depict close-up perspective cutaway views of an alternative positive-engagement capture mechanism 150 to that shown in FIG. 4. FIG. 6A shows the cams in a closed configuration, and FIG. 6B shows the cams in an open configuration. According to the embodiment of FIGS. 6A and 6B, the alternative positive-engagement capture mechanism 150 can reliably capture rotating UAVs with a protruding spike on the lower side, by using a rotating clamp or chuck to tightly clamp the spike of UAV, according to an alternative embodiment of the present invention.

In this example embodiment, multiple cams 610, 611 may be used to perform a clamping motion during rotation. A servo 620 actuates a lever 625, which in turn raises and lowers an actuator 630. Actuator 630 may be substantially free to spin via a bearing 631 , together with the tube 640 which spins via bearings 641 , 642. Linkages 651 and pushrods 652 convert vertical motion of the actuator 630 into clamping motion of the cams 610, 61 1.

If the UAV’s axis of rotation, and hence axis of protruding tail-spike, is not vertical, the tip of the spike can enter the opening of the mechanism, which may substantially constrain its horizontal motion. The UAV 190 can then use pitch and roll control to align the axis extending through the protruding tail-spike with the capture mechanism 150, to in turn insert the tail spike into the capture mechanism 150 before clamping by the cams 610, 61 1 occurs.

In alternative embodiments, a chuck-like mechanism may be used, similar to those used in drills or lathes.

In alternative embodiments, additional control of tilt of the entire mechanism may be achieved with additional actuators, allowing for the spinning UAV to land in the mechanism without re-orienting its axis of rotation.

Referring now to FIGS. 7, 8 and 9, an alternative embodiment of an active docking station 700 may be arranged in an open configuration (shown in FIG. 9) or a closed configuration (shown in FIG. 7). FIG. 9 illustrates an example operation, whereby a UAV 190 approaches the docking station 700 for landing toward a capture mechanism 750. The active docking station 700 includes a base structure 710. A robotic motion system 740 may consist of a delta robot, a type of 3-degree-of-freedom parallel robot with three actuators, and such delta robots are well known in the art of robotics. The actuators may be rotary actuators 741 which move three lower arms 742 as shown in FIGS. 7 and 9, or may be linear actuators. The actuators may act on six upper arms 743, which connect the lower arms 742 to the effector via ball-and-socket joints 744, such that the effector can move in three dimensions while generally maintaining its orientation relative to the base structure 710 of the docking station 700. The effector of the delta robot may contain the capture mechanism 750, as shown in FIGS. 7 and 9, or may consist of additional mechanisms which can further tilt the capture mechanism 750, such that its orientation can change relative to the base structure 710.

The robotic motion system 740 can move in three dimensions, including in the vertical direction, and allows for a UAV 190 to be lifted out of the enclosure of the docking station 700, so that the overall dimensions of the docking station 700 can be minimised. Smaller overall dimensions can ensure the whole docking station 700 is portable such that it can be installed or moved without heavy-lifting equipment, so the docking station 700 may further include lifting handles 715 to ease handling by one or more humans.

When a UAV 190 is landing, the robotic motion system 740 may initially move the capture mechanism 750 horizontally such that it aligns vertically with the UAV 190, and may then accelerate rapidly upwards to physically engage the UAV 190, once the UAV 190 descends to within a certain proximity of the capture mechanism 750 and while good alignment is detected.

An opening and closing enclosure mechanism may consist of top lid panels 720 and side lid panels 721 connected by hinges 722, and lid linkages 723, arranged in a 4-bar-linkage arrangement. Rotary actuators 725 may be used to open and close the enclosure mechanism by rotating either side lid panels 721 , as shown in FIG. 7, or by rotating lid linkages 723.

FIG. 8 shows a close-up view of an opening and closing mechanism which consists of a 4-bar linkage, with pivots 801 and 802 fixed to the base structure 710. The top lid panel 720, side lid panel 721 , hinge 722 and lid linkage 723 are shown in a closed configuration with solid lines, and shown in the open configuration with short dashed lines. Dashed arrows indicate the motion of the two moving pivot-points of the 4-bar linkage. The enclosure mechanism provides a large opening in the top of the docking station 700 when in the open configuration, to provide clearance for UAVs 190 to launch and land. The enclosure mechanism has the advantage of never protruding far from the base structure 710, minimising the overall dimensions of the docking station 700 while open and closed and during opening and closing.

Since the system may be configured to be deployed in remote locations, and the UAV 190 may be exposed to dirt, dust, and moisture or salt water, the docking station 100 may also include a washing system for the UAV 190. The washing system may include some combination of water-jets, pressurised air jets, or fans, to remove the dust, dirt, or water from the UAV 190. Additionally, the enclosure may include systems for humidifying the air and/or dehumidifying the air, or flushing or replacing air in the enclosure with clean air or inert gas. Humidifying, dehumidifying, and flushing are can all extend the operational lifetime of a UAV and its various subsystems, including payloads.

Additionally, the enclosure may include systems for cooling and/or warming the air contained inside the enclosure. Avoiding extreme high or low temperatures can extend the operational lifetime of a UAV, its batteries, and various subsystems, including payloads.

The active docking station may include and integrate any other physical components which may be used in the operation, maintenance, service, and/or storage of UAVs. Such components may include: UAV communications systems or ground control stations, such that a docking station can integrate the communications involved in commanding and/or operating a UAV, and retrieve live telemetry data therefrom; and external communications system to connect the active docking station to external networks such as the Internet, to enable the docking station to send and receive data from the external sources, to in turn facilitate remote operation ( e.g ., a live datastream can be relayed from a UAV to an external network for remote monitoring, and commands can be received and/or relayed to a UAV for control purposes).

Although certain example methods and apparatus have been described herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatuses, and articles of manufacture fairly falling within the scope of the appended claims, either literally or under the doctrine of equivalents. Accordingly, this patent specification is intended to embrace all alternatives, modifications and variations of the present invention that have been discussed herein, and other embodiments that fall within the spirit and scope of the above described invention.

It should be understood that arrangements described herein are for purposes of example only. As such, those skilled in the art will appreciate that other arrangements and other elements (e.g. machines, interfaces, operations, orders, and groupings of operations, etc.) can be used instead, and that some elements may be omitted altogether, according to the desired results. Further, many of the elements that are described are functional entities that may be implemented as discrete or distributed components or in conjunction with other components, in any suitable combination and location, or as other structural elements described as independent structures may be combined.

While various aspects and implementations have been disclosed herein, other aspects and implementations will be apparent to those skilled in the art. The various aspects and implementations disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope being indicated by the following claims, along with the full scope of equivalents to which such claims are entitled. It is also to be understood that the terminology used herein is for the purpose of describing particular implementations only, and is not intended to be limiting.