CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to and benefit of U.S. Provisional Application No. 63/319,014 filed March 11, 2022, the disclosure of which is hereby incorporated by reference herein in its entirety.

TECHNICAL FIELD

[0002] The present application relates to a power-driven shoe device with a decentralized control circuit.

BACKGROUND

[0003] With increasing urban populations and concerns of disease transmission on shared commuting methods, such as public transportation, the last kilometer problem, that is, a relatively long and time-consuming final walking distance, remains an issue for the commuting public. Various solutions exist on the market to improve the last kilometer problem including electric powered transportation devices, such as electric roller skates.

[0004] The current market solutions of electric roller skates present problems with ergonomics and safety. Abnormal posture and gait cycle can create discomfort and require excess physical exertion. These issues are compounded by the increasing complexity of urban roads and sidewalks where commuters must enter and exit sidewalks while avoiding obstacles such as holes, grates, or puddles. This complexity makes the user unable to walk normally in electric roller skates, thereby greatly reducing the practicality of current technologies. Current wheel configurations that are under the user’s sole present challenges when going over obstacles and present dangerous scenarios resulting from sudden deceleration or unexpected stopping. Moreover, the bulk of the electronic equipment required to drive the transportation device reduces the applicability and ergonomic use due to increased weight and width. As such, the skates may impact each other or obstacles during use. Furthermore, with the recent appearance of multi-body electric roller skates, the hinge point creates undesirable compression of the user’s foot and allows for a source of instability at certain angles of the foot relative to the ground plane, whereby the number of wheels in contact with the ground is suddenly reduced.

[0005] Safety concerns stem from current electric roller skates lacking the ability to manage the wearer’s speed in emergency scenarios. Specifically, current electric roller skates suffer from syncing issues between the two skates. In some models, individual skates do not communicate at all, which can result in the two skates producing different velocities. In some models, the two skates do communicate using two-way communication, which can lead to decision making latency for the skates. A decentralized control method, employing oneway communication, is needed to keep the two skates synchronized and responsive.

SUMMARY

[0006] In some embodiments, a power-driven shoe includes a shoe sole comprising a sole portion and a toe portion, a plurality of rotatable wheels disposed below the shoe sole, a motor disposed below the shoe sole, wherein the motor is in driving connection with at least one of the plurality of rotatable wheels, a control circuit interfaced to the motor; and a network adapter, interfaced to the control circuit, wherein the network adapter is configured to communicate to a second power-driven shoe using one-way communication.

[0007] In some embodiments, the plurality of rotatable wheels include a toe grouping of rotatable wheels disposed under the toe portion, a middle grouping of rotatable wheels disposed under a front portion of the heel portion, and a heel grouping of rotatable wheels disposed under a rear portion of the heel portion.

[0008] In some embodiments, the motor is interfaced to at least one rotatable wheel of the middle grouping and at least one rotatable wheel of the rear grouping.

[0009] In some embodiments, the power-driven shoe includes a gearbox housing comprising a geared drivetrain system.

[0010] In some embodiments, the power-driven shoe includes a strap, configured to attach the power-driven shoe to a user’s shoe or foot, interfaced directly to the gearbox housing.

[0011] In some embodiments, the control circuit is within the gearbox housing.

[0012] In some embodiments, the power-driven shoe further comprises a power module within the gearbox housing.

[0013] In some embodiments, the power module is interfaced to the control circuit via one or more electromechanical connectors.

[0014] In some embodiments, the motor is a brushless direct current motor.

[0015] In some embodiments, the power-driven shoe includes a hall effect sensor integrated into the motor and interfaced with the control circuit.

[0016] In some embodiments, a magnet of the motor is extended beyond the length of a coil of the motor.

[0017] In some embodiments, the power-driven shoe includes an inertial measurement unit interfaced to the control circuit.

[0018] In some embodiments, the power-driven shoe includes a remote control device configured to interface to the network adapter.

[0019] In some embodiments, a method of controlling a velocity of a power-driven shoe includes calculating a first velocity of the power-driven shoe based on the input of an inertial measurement unit and a motor sensor, transmitting the first velocity to a paired power-driven shoe, receiving a second velocity from the paired power-driven shoe, determining if the first velocity and second velocity match, in response to the first and second velocity not matching: determining a safer velocity between first and second velocity and operating the motor at the safer velocity; and in response to the first and second velocity matching: operating the motor at the first velocity.

[0020] In some embodiments, calculating the first velocity further comprises detecting a motor torque from the motor sensor, determining a gait state of the power-driven shoe based on the motor torque, transforming the motor torque into a force tangential to a wheel of the power-driven shoe, and in response to detecting a pre-determined gait state: capturing a wheel force, normalizing the wheel force based on a baseline wheel force, determining an acceleration based on the normalized wheel force, and determining the first velocity based on the acceleration.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Aspects and embodiments of this application are depicted in the figures, wherein:

[0022] FIG. 1 A depicts a perspective view of a power-driven shoe in accordance with an embodiment.

[0023] FIG. IB depicts a perspective view of a strapping mechanism of a power- driven show in accordance with an embodiment.

[0024] FIG. 2 depicts a side view of a power-driven shoe in accordance with an embodiment.

[0025] FIG. 3 depicts a view of the underside of a power-driven shoe in accordance with an embodiment. [0026] FIG. 4A depicts an illustrative logical block diagram of a control system for a power-driven shoe in accordance with an embodiment.

[0027] FIG. 4B depicts a small brushless direct current motor configuration in accordance with an embodiment.

[0028] FIG. 5A depicts the internal components of the control system in accordance with an embodiment.

[0029] FIG. 5B depicts an alternative view of the internal components of the control system in accordance with an embodiment.

[0030] FIG. 5C depicts another alternative view of the internal components of the control system in accordance with an embodiment.

[0031] FIG. 6A depicts the interface of the motor and the gearbox in accordance with an embodiment.

[0032] FIG. 6B depicts an alternative view of the interface of the motor and the gearbox in accordance with an embodiment.

[0033] FIG. 7 depicts an illustrative flow diagram for a method of controlling a velocity for a power-driven shoe in accordance with an embodiment.

[0034] FIG. 8 depicts an illustrative flow diagram for a data in power-driven shoe system comprising a remote controller in accordance with an embodiment.

[0035] FIG. 9 depicts an illustrative flow diagram for predetermining a no-loading wheel force in accordance with an embodiment.

[0036] FIG. 10 depicts an illustrative flow diagram for determining a force-based acceleration in accordance with an embodiment.

[0037] FIG. 11 depicts an illustrative flow diagram for changing modes of operation in accordance with an embodiment. DETAILED DESCRIPTION

[0038] This disclosure is not limited to the particular systems, devices and methods described, as these may vary. The terminology used in the description is for the purpose of describing the particular versions or embodiments only and is not intended to limit the scope of the disclosure.

[0039] The following terms shall have, for the purposes of this application, the respective meanings set forth below. Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art. Nothing in this disclosure is to be construed as an admission that the embodiments described in this disclosure are not entitled to antedate such disclosure by virtue of prior invention.

[0040] As used herein, the singular forms “a,” “an,” and “the” include plural references, unless the context clearly dictates otherwise. Thus, for example, reference to a “cell” is a reference to one or more cells and equivalents thereof known to those skilled in the art, and so forth.

[0041] As used herein, the term “about” means plus or minus 10% of the numerical value of the number with which it is being used. Therefore, about 50mm means in the range of 45mm to 55mm.

[0042] As used herein, the term “consists of’ or “consisting of’ means that the device or method includes only the elements, steps, or ingredients specifically recited in the particular claimed embodiment or claim.

[0043] In embodiments or claims where the term “comprising” is used as the transition phrase, such embodiments can also be envisioned with replacement of the term “comprising” with the terms “consisting of’ or “consisting essentially of.” [0044] As will be understood by one skilled in the art, for any and all purposes, such as in terms of providing a written description, all ranges disclosed herein are intended as encompassing each intervening value between the upper and lower limit of that range and any other stated or intervening value in that stated range. All ranges disclosed herein also encompass any and all possible subranges and combinations of subranges thereof. Any listed range can be easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, tenths, et cetera. As a nonlimiting example, each range discussed herein can be readily broken down into a lower third, middle third and upper third, et cetera. As will also be understood by one skilled in the art, all language such as “up to,” “at least,” and the like include the number recited and refer to ranges that can be subsequently broken down into subranges as discussed above. Finally, as will be understood by one skilled in the art, a range includes each individual member. Thus, for example, a group having 1-3 components refers to groups having 1, 2, or 3 components as well as the range of values greater than or equal to 1 component and less than or equal to 3 components. Similarly, a group having 1-5 components refers to groups having 1, 2, 3, 4, or 5 components, as well as the range of values greater than or equal to 1 component and less than or equal to 5 components, and so forth.

[0045] In addition, even if a specific number is explicitly recited, those skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number (for example, the bare recitation of "two recitations," without other modifiers, means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, et cetera” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (for example, “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, et cetera). In those instances where a convention analogous to “at least one of A, B, or C, et cetera” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (for example, “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, et cetera). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, sample embodiments, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.”

[0046] In addition, where features of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group.

[0047] The present disclosure provides the control methods and systems configured for safe and ergonomic operation of a power-driven shoe. Furthermore, the power-driven shoe features an emergency braking system for slowing the shoe in the event of a loss of signal from the control circuit, which most likely signifies a loss of power (i.e., the shoe being shut off during operation, a battery depletion/failure, or an electrical connection issue).

[0048] Referring to FIG. 1 A, a perspective view of a power-driven shoe 100 is depicted in accordance with an embodiment. The power-driven shoe 100 comprises a sole. In some embodiments, the sole comprises two or more independent elements configured to rotate or translate in relation to one another. For example, the power-driven shoe 100 may comprise a heel portion 101 and a toe portion 102. In some embodiments, the heel and toe portions 101, 102 may be joined via one or more translating hinges. In some embodiments, the one or more translating hinges may be disposed under the ball of a user’s foot. An example of use of a hinge in the context of a power-driven shoe is described in U.S. Patent Application No. 17/507,270 filed October 21, 2021 and entitled "Power-Driven Shoe Device Wheel Configuration with Combined Translational and Rotational Hinge Mechanism and Integrated Gear-Bushing Assembly," the entirety of which is incorporated herein by reference.

[0049] In certain embodiments, a strapping mechanism 107 may be disposed above the heel portion 101. Referring to FIG. IB, the strapping mechanism 107 may be configured to accept one or more straps or buckles, thereby allowing the user to attach the power-driven shoe to their foot. In some embodiments, the strapping mechanism 107 is connected under the shoe sole using a plurality of cylindrical pins 110 to interface the sole of the shoe and fastener driven compression components 111. In certain embodiments, the plurality of cylindrical pins 110 connect the strapping mechanism 107 directly to the gearbox housing. In some embodiments, the strapping mechanism 107 may be a magnetic buckle. In some embodiments, the strapping mechanism 107 is semi-rigid (i.e., flexible) and is configured to allow for the correct locational position of the strapping elements that secure a user’s foot to the sole portion of the shoe for long-term use and comfort. In further embodiments, the positioning is further aided by the slots 112 in the strapping mechanism that allow for minor translation during use. In some embodiments, the strapping mechanism 107 is configured to function as a handle to carry the power-driven shoe when not in use.

[0050] In certain embodiments, the power-driven shoe 100 comprises a plurality of wheels disposed below the sole of the shoe. In some embodiments, the plurality of wheels are separated into one or more groups. In further embodiments, the one or more groups of wheels may comprise at least one of a group disposed under the toe of the shoe 103, a group disposed under the middle of the shoe 104, and a group disposed under the heel of the shoe

105

[0051] In certain embodiments, the power-driven shoe 100 comprises a motor 106 in driving connection with at least a portion of the plurality of wheels. In some embodiments, the portion of the plurality of wheels in driving connection with the motor 106 comprises at least one of the wheels in the middle group 104 and at least one of the wheels in the heel group 105. In some embodiments, the motor 106 is in driving connection with at least a portion of the plurality of wheels using one or more gears. Referring briefly to FIG. 2, in which an alternate view of a power-driven shoe 100 is depicted, the one or more gears may be housed in a gearbox housing 201 in accordance with an embodiment. In some embodiments, the gearbox housing 201 is disposed below the shoe sole.

[0052] In some embodiments, the gearbox housing 201 comprises a geared drivetrain system, wherein the geared drivetrain system comprises bushings integrated into at least one drive gear.

[0053] FIG. 3 depicts a view of the underside of a power-driven shoe 100 in accordance with an embodiment. In some embodiments, the gearbox housing 201 is mounted underneath the sole of the power-driven shoe. In some embodiments, the gearbox housing 201 may house a power module. In some embodiments, the gearbox housing 201 may be subdivided into two or more housings. In some embodiments, a first housing of the gearbox housing 201 may comprise a power module and a second housing of the gearbox housing may comprise drive gears.

[0054] In certain embodiments, the power-driven shoe 100 comprises a power module. The power module may comprise circuitry components, a battery, and one or more connections between the circuitry components and the battery. In some embodiments, the power module may constrain movement of the battery and prevent intrusion by outside elements. In some embodiments, the circuitry components may be mounted within the power module. In such embodiments, the power module may fixedly hold the position and configuration of the circuitry components during use of the power-driven shoe. The exterior of the power module may further prevent debris and moisture from reaching the circuitry components, the battery, and/or the connections. In some embodiments, wire routing and movement may be further constrained within the power module to improve the reliability of the power-driven device.

[0055] In some embodiments, the circuitry components may comprise a control circuit, one or more sensors, and one or more network communication adapters.

[0056] FIG. 4A depicts an illustrative block diagram of a control system 400 for a power-driven shoe in accordance with an embodiment. In some embodiments, the control system comprises a control circuit 401. In further embodiments, the control circuit 401 comprises one or more processors and a non-transitory storage medium, such as one or more memory devices, containing programming instructions for the one or more processors. In some embodiments, the non-transitory storage medium comprises non-volatile memory or flash memory. An illustrative control system in the context of a power-driven shoe is described in U.S. Patent Application No. 17/421,479 filed July 8, 2021 and entitled "A Method and Device for Control of a Mobility Device Using an Estimated Gait Trajectory," the entirety of which is incorporated herein by reference.

[0057] In certain embodiments, the control circuit 401 is in operable communication with the motor 402 and is configured to control the operation of the motor 402. In some embodiments, the control circuit 401 receives status information from at least one sensor associated with the motor 402. In some embodiments, the status information comprises at least one of a current, a position, a speed, and/or a direction of the rotating motor. [0058] In certain embodiments, the control circuit 401 is operably connected with a battery 403. The battery 403 may comprise one or more batteries in series or parallel as will be apparent to those of ordinary skill in the art. In some embodiments, the control circuit 401 may be configured to monitor the status of the battery 403 through an integrated sensor. In some embodiments, the integrated sensor may measure a current on one or more terminals of the battery. In some embodiments, the control circuit 401 may electrically couple or decouple one or more electrical components within the power-driven shoe 100 from the battery 403. Coupling or decoupling the one or more electrical components may be performed in response to status information received from other components of the power- driven shoe 100, such as the motor 402.

[0059] In some embodiments, the control circuit 401 is in operable communication with a network adapter 404. In some embodiments, the network adapter 404 comprises a wireless adapter. The wireless adapter may be configured to receive and/or transmit signals via IEEE 802.11 wireless, Bluetooth®, or through any other wireless technology or protocol. In some embodiments, the network adapter 404 may alternatively or additionally include a wired interface. In such embodiments, the wired interface may include a Universal Serial Bus connection.

[0060] In certain embodiments, the network adapter 404 facilitates communication with an external processor and/or a storage device for at least one of updating the programming instructions on the control circuit 401 (e.g., firmware update or pairing two shoes together), relaying system data, relaying usage data, or relaying data for external control processing.

[0061] In certain embodiments, the network adapter 404 facilitates communication between two power-driven shoes worn by a user. In some embodiments, the cross-shoe communication is configured to maintain synchronization between the two power-driven shoes during a user’s gait. In further embodiments, the synchronization is improved through decentralized control between the two power-driven shoes.

[0062] In certain embodiments, the power-driven shoe may comprise one or more inertial measurement units 405 in operable communication with the control circuit 401. In some embodiments, the one or more inertial measurement units 405 comprise one or more accelerometers and/or gyroscopes.

[0063] In certain embodiments, the motor 402 may be a brushless direct current (BLDC) motor. In some embodiments, the BLDC motor may feature a magnetic Hall effect sensor to aid in speed control. Typical BLDC motors, with large rotors (i.e., greater than 45mm), integrate the magnetic Hall effect sensor directly onto the coil of the motor. Smaller BLDC motors (i.e., smaller than 45mm) have coils too small for the magnet and require an external interface for the magnets. The problem with this configuration in small BLDC motors, is that magnetic interference from the coil may distort the magnetic field caused by the moving magnets. Referring to FIG. 4B, an alternative small BLDC motor configuration 410 is depicted in accordance with an embodiment. To ensure the magnetic Hall effect sensors 413 consistently detect movement regardless of the coil 411 current, the magnet 412 length is extended over the coil 411 length so that the magnetic fields from the magnets 412 are stronger than the magnetic interference. The arrangement can ensure that the magnetic fields, even at the furthest distance between the magnets 412 and the Hall effect sensors 413, are measurable over the magnetic interference from the coil 411 at peak operating current.

[0064] Referring to FIG. 5 A, the internal components of the control system 500 are depicted in accordance with an embodiment. In certain embodiments, the control system comprises a power module 501, which further comprises circuitry components 502, a battery 503, and one or more connections between the circuitry components 502 and the battery 503. In certain embodiments, the power module 501 may be mounted inside of the gearbox housing 201. In some embodiments, the power module 501 may constrain movement of the battery 503. In some embodiments, the circuitry components 502 may be mounted within the power module 501. In such embodiments, the power module 501 may fixedly hold the position and configuration of the circuitry components 502 during operation of the power- driven shoe.

[0065] Briefly referring to FIGS. 5B and 5C, the battery current is routed directly through electromechanical connectors 505 to the circuitry components 502 where additional electrical signals are relayed through a plurality of connectors 506. The electromechanical connectors 505 eliminate wired connections and accurately position the circuitry components 502, including sensors required for control. The wireless connection eliminates the need for bulk capacitors and increases the reliability of the power-driven device.

[0066] Referring to FIG. 6A, the interface of the motor and the gearbox 601 is depicted in accordance with an embodiment. In certain embodiments, a plurality of low- friction circumferential locators 602 are used to ensure proper alignment of the input shaft 603 to the input gear 604. In some embodiments, the configuration provides efficient torque transfer from the motor to the gearbox 601 without the use of fasteners to secure the rotating shafts together. In further embodiments, the configuration compensates for shaft misalignment and reduces runout error of the connection, which may extend gear life and greatly reduce stress concentrations at the connecting interface. In some embodiments, the circumferential locators are located inside of the gearbox 601. The resulting configuration may allow the input shaft to be replaced multiple times without the need for ring destruction. Furthermore, the presented quick installation and detachment assembly method may reduce Takt time in assembly and increase serviceability.

[0067] Referring to FIG. 6B, another view of the motor and gearbox interface of

FIG. 6A is depicted. In certain embodiments, the alignment of the input shaft 603 to the gearbox 601 is accomplished using geometric features 606/607 imparted on both the motor 605 and the gearbox 601, respectively. In some embodiments, assembly of the drivetrain may comprise sliding the alignment feature on the motor 606 into the alignment feature on the gearbox 607 and positioning the motor and fastening it to the gearbox. The embodiment depicted in FIGS. 6 A and 6B allows for a repeatable, simple alignment during installation without dependence on fasteners.

[0068] Referring to FIG. 7, an illustrative method of controlling a velocity for a power-driven shoe is disclosed in accordance with an embodiment. In some embodiments, the method 700 may comprise calculating a velocity 701 for a shoe, independently from the other shoe, based on one or more factors. In some embodiments, the one or more factors comprise data received from one or more sensors, as disclosed herein. In certain embodiments, calculating a velocity 701 may further comprise estimating a gait trajectory and calculating a reference acceleration as disclosed in U.S. Patent Application No. 17/421,479. The algorithm may be refined through incorporation of data from the sensors associated with the motor and battery. As a non-limiting example, data from the motor sensor may allow the control circuit 401 to augment the gait trajectory based on real trends with in-motor activities (i.e., torque). In another non-limiting example, if a battery sensor detects a current indicating that the battery may be dying, the control circuit 401 may augment the reference acceleration to preserve battery life. In some embodiments, currently collected gait data may be referenced against stored historical gait data. In further embodiments, the historical gait data may comprise the most recent step taken by the user. A person having ordinary skill in the art will recognize that an inertial measurement unit may capture extraneous data when the power-driven shoe is traveling on uneven surfaces. In some embodiments, data collected from sensors associated with either the motor or battery may be used to compensate for the extraneous data. [0069] In some embodiments, the independent velocity is communicated 702 with the control circuit 401 on the other shoe 100. In certain embodiments, each shoe 100 crosschecks 704 the locally calculated velocity against the velocity calculated by and received from the other shoe 703. In instances where the locally calculated and remotely calculated velocities match, the system directs the motor to cause the shoe 100 to move at the calculated velocity 706. In some instances where the locally calculated and remotely calculated velocities do not match, a correct velocity may be determined 705. In some embodiments, the correct velocity comprises a velocity that results in safer transport of the user. In some embodiments, calculating the correct velocity comprises at least one of choosing the lesser velocity, choosing the closest velocity to a previously determined velocity, or choosing a velocity within a threshold of a previously selected velocity. In some instances where the locally calculated and remotely calculated velocities do not match, the control circuit 401 may transmit a signal indicating the mismatch via the network adapter 404. In some embodiments, the signal may be a negative acknowledgement. In other embodiments, the signal may comprise the calculated correct velocity.

[0070] A person having ordinary skill in the art will note that in the decentralized control system presented herein, the power-driven shoes may have increased performance due to each shoe only requiring one-way communication from the other shoe. By eliminating the requirement of feedback on every command (i.e., two-way communication), both power- driven shoes may operate with improved responsiveness and synchronization. Furthermore, the control circuit 401 on each power-driven shoe will face a lower computational load as a result of the distribution, thereby limiting a computational bottleneck.

[0071] In certain embodiments, the network adapter 404 facilitates communication to a remote device configured to provide control inputs to the power-driven shoe. Referring to FIG. 8, a system configuration 800 is depicted comprising a remote controller 801 and left 802 and right 803 power-driven shoes in accordance with an embodiment. In some embodiments, the remote controller 801 may be a mobile computing device, such as a cellular phone. In other embodiments, the remote controller 801 may be a dedicated device configured for control of the power-driven shoes 802/803. In some embodiments, the remote controller 801 may only set configuration and read status of the power-driven shoes 802/803. In some embodiments, the remote controller 801 may facilitate control for the entire system 800. In some embodiments, the remote controller 801 may receive gait estimates based on input from a single shoe 804. In further embodiments, the shoe may additionally calculate gait control based on a real-time preprocessed data exchange 805 between the two power- driven shoes 802/803, as disclosed herein. Limiting the remote controller 801 to receiving estimations based on each single shoe may prevent a communication or computational bottleneck at the remote controller 801. In an alternative embodiment, the remote controller 801 may receive status information based on previously stored gait data based on the data exchange 805 between the power-driven shoes 802/803.

[0072] In certain embodiments, the control circuit 401 may interpret the force applied to the wheels of the power-driven shoe by sensing the motor torque. In some embodiments, the applied force is used as an additional input to classify if the leg is in swing or stance phase, by comparing the current wheel force against a predetermined no-loading wheel force. Referring to FIG. 9, a method of predetermining a no-loading wheel force 900 is depicted in accordance with an embodiment. In some embodiments, predetermining the no-loading wheel force 900 may require the use of a remote controller. In some embodiments, predetermining a no-loading wheel force 900 may comprise positioning the shoes free from any external loading 901, requesting a calibration 902, commanding the shoes through a series of various drivetrain speeds 903, determining the drivetrain loading 904, and storing the parameters 905. In some embodiments, calibration may be performed on the user’s foot. In some embodiments, a calibration may be performed on a mount for the power-driven shoe. Calibration on a mount may provide an initial calibration during manufacture. In alternative embodiments, a user may be required to provide an initial calibration prior to usage of the power-driven shoe. The no-loading wheel force 900 is a notable metric because, during swing phase, when user’s leg is in the air, the motor torque is only required to overcome friction in the gearbox. By comparison, in stance phase, the motor torque is additionally overcoming the friction between the wheels and the ground.

[0073] In certain embodiments, acceleration of the power-driven shoe may be determined based on the force applied to the shoe. In some embodiments, force-based acceleration is used in addition to gait-based acceleration. In other embodiments, force-based acceleration may be used as an alternative to gait-based acceleration.

[0074] Referring to FIG. 10, a method of determining a force-based acceleration 1000 is illustrated in accordance with an embodiment. The method 1000 may comprise sensing a motor torque from the stance leg and the stride velocity from the swing leg 1001. Determining the stance of the leg may be performed using the above-referenced comparison to the no-loading wheel force. The system may convert the motor torque to the force tangential to the wheel 1002. In some embodiments, the system may wait until a detectable consistent state in the gait 1003. In some embodiments, the state in the gait is the peak stride velocity. In some embodiments, the system may capture the current wheel force 1004. In some embodiments, the wheel force is captured a predefined time from the detection event. The wheel force may be compared 1006 to a baseline wheel force 1005. In some embodiments, the comparison comprises subtracting the wheel force 1006 from the baseline wheel force 1005. In some embodiments, the baseline wheel force is captured at the detection event. In some embodiments, if no baseline wheel force is available, the controlled acceleration is set to zero 1008 for safety. After the comparison 1006, the difference between the current and baseline wheel force may be applied to determine the force-based acceleration

1007

[0075] In certain embodiments, various modes of operation may be required to accommodate varying commuting scenarios. The standard mode, described above, allows users to control the device motion (e.g., acceleration, deceleration, turning, and cruising) with their natural gaits. In some embodiments, a stationary mode may be incorporated in which the wheels are locked. Locking the wheels may comprise some combination of applying a braking system or applying motor torque to hold the wheel in place. As a non-limiting example, a stationary mode may be advantageous when users need to use stairs, board a vehicle, or traverse rough terrain. In further embodiments, additional modes may be available, such as a free skate.

[0076] In certain embodiments, users may change modes through a remote controller or interface on the power-driven shoe. In some embodiments, users may change modes through poses. In some embodiments, at least a portion of mode changes may require the shoe to be stationary to accommodate a safe transition. In some embodiments, a single input may be used to toggle through multiple modes. In some embodiments, a first input may be tied to a transition from a first mode to a second mode, and a second input may be used to transition from the second mode to the first mode. In some embodiments, a pose used to change modes may be either preconfigured by the manufacturer or configured by the user. To transition to another mode, the user may perform a preconfigured pose. In some embodiments, a pose may comprise some combination of lifting a foot, dropping a foot, or angling a foot vertically or horizontally. In further embodiments, a series of these movements may be combined in a specified order to create a sequence of poses. In additional embodiments, completing a sequence of poses in a predetermined time frame may be required to change a mode. In some embodiments, a visual, audio, or haptic feedback response may notify the user of a change in mode. In some embodiments, the feedback response interface may be included with the power-driven shoe. In some embodiments, the feedback response interface may be included in the remote controller.

[0077] In certain embodiments, the system may initiate in an initialization mode. In some embodiments, the initialization mode may comprise the wheels being in a locked state for safety. In some embodiments, the system may include one or more additional requirement to leave the locked state in initialization. In some embodiments, the requirements comprise the performance of a recent calibration.

[0078] Referring to FIG. 11, an illustrative control method for two modes of operation 1100 is depicted, in accordance with an embodiment. In some embodiments, the device may enter a locked state or “Mode One” 1101 when powered on. The control circuit may check if the device is stationary 1102 and/or if the unlock pose is completed 1103 as a requirement for allowing the device to enter the standard operational mode “Mode Two” 1104. To return to “Mode One” 1101, the control circuit may check if the device is stationary 1105 and/or the lock pose is completed 1107. In some embodiments, entering “Mode One” 1101 may additionally require performing the unlock pose 1106.

[0079] While the present disclosure has been illustrated by the description of exemplary embodiments thereof, and while the embodiments have been described in certain detail, the Applicant does not intend to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the disclosure in its broader aspects is not limited to any of the specific details, representative devices and methods, and/or illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the Applicant's general inventive concept. [0080] In the above detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the present disclosure are not meant to be limiting. Other embodiments may be used, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that various features of the present disclosure, as generally described herein, and illustrated in the Figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein.

[0081] The present disclosure is not to be limited in terms of the particular embodiments described in this application, which are intended as illustrations of various features. Instead, this application is intended to cover any variations, uses, or adaptations of the present teachings and use its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which these teachings pertain. Many modifications and variations can be made to the particular embodiments described without departing from the spirit and scope of the present disclosure as will be apparent to those skilled in the art. Functionally equivalent methods and apparatuses within the scope of the disclosure, in addition to those enumerated herein, will be apparent to those skilled in the art from the foregoing descriptions. It is to be understood that this disclosure is not limited to particular methods, reagents, compounds, compositions or biological systems, which can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0082] Various of the above-disclosed and other features and functions, or alternatives thereof, may be combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art, each of which is also intended to be encompassed by the disclosed embodiments.