Self-aligning mechanisms in passive and powered exoskeletons

Abstract

An exoskeleton device includes an artificial joint and a frame member extending from the artificial joint. The frame member is configured for extension onto a user's limb. The exoskeleton device also includes a self-aligning mechanism connected to the frame member. The self-aligning mechanism includes three passive degrees of freedom (pDOF) provided in a prismatic-rotatory-rotatory (PRR) configuration. The self-aligning mechanism also includes a limb attachment member configured for mechanical coupling to a portion of the user's limb.

Description

Technical Field

[0001] Government Rights This invention was made with government support under award number W81XWH-16-1-0701 from the Department of Defense / DARPA. The government has certain rights in this invention. Cross - Reference to Related Applications

[0001] This application claims the benefit and priority of U.S. Provisional Patent Application No. 62 / 992,631, filed on March 20, 2020, entitled "SELF-ALIGNING MECHANISMS IN PASSIVE AND POWERED ORTHOSES", the entire disclosure of which is incorporated herein by reference.

Background Art

[0002]

[0002] Exoskeletons, such as powered exoskeletons, are used for various purposes, such as rehabilitation, assistance, strength amplification, productivity improvement, and / or others. Powered exoskeletons operate by transmitting a controlled amount of torque to the wearer's body. However, transmitting torque to the wearer's body in a safe, comfortable, and / or effective manner is associated with many challenges. For example, there is high variability in the anatomical measurements and ratios between different humans. Furthermore, the shape and / or volume of a human limb change due to muscle activity and physical interaction with the exoskeleton. Certain challenges in the effective implementation of an exoskeleton are related to aligning the exoskeleton's axes of rotation and / or translation (e.g., artificial joints) with the anatomical axes of rotation and / or translation (e.g., anatomical joints) of the human user.

[0003]

[0003] Misalignment between an artificial joint and an anatomical joint can result in incorrect forces and / or torques being applied to the user. And the incorrect forces and / or torques can result in undesirable loads on the anatomical joint and / or shear stress on the user's skin. Such undesirable loads and / or shear stress can reduce user comfort and / or user safety when operating the exoskeleton.

[0004]

[0004] Therefore, there is a current need for a mechanism that can improve the exoskeleton. In particular, there is a current need for a mechanism that can effectively align an anatomical joint with the artificial joint of the exoskeleton. The subject matter claimed herein is not limited to embodiments that solve any disadvantages or to embodiments that operate only in environments such as those described above. Rather, this background is provided only to illustrate one exemplary technical field in which some of the embodiments described herein may be practiced.

Summary of the Invention

Means for Solving the Problems

[0005]

[0005] Disclosed herein is a self-aligning mechanism that can be utilized in an exoskeleton (powered or unpowered) to dynamically align an anatomical joint and an exoskeleton joint. An exoskeleton including the self-aligning mechanism can be configured to adjust to the unique kinematics and movements of an individual user to avoid or reduce uncomfortable or harmful incorrect forces and / or torques on the user.

[0006]

[0006] The self-aligning mechanism uses a combination of linear and rotational passive degrees of freedom and / or elastic elements to dynamically align the anatomical joint and the artificial joint. The self-aligning mechanism is added in series within the human-robot kinematic chain. These self-aligning mechanisms can be utilized in passive or powered exoskeletons (or orthotic devices) such as powered hip exoskeletons or powered knee exoskeletons.

[0007]

[0007] The self - alignment mechanism advantageously functions to provide a dynamic alignment of the working axis and the anatomical axis in a manner that takes into account variations in user anthropometry while advantageously minimizing stress on the user's joints and soft tissues. The self - alignment mechanism is configured to transmit torque to the intended joints while reducing undesirable loads on the limbs.

[0008]

[0008] The self - alignment mechanism described herein enables a dynamic alignment of the working axis and the anatomical axis for various types of user anatomical structures. This enables a potentially lighter exoskeleton with reduced need for customization and fewer individual customization features, due to the reduced need for customization.

[0009]

[0009] Some embodiments provide an exoskeleton device including an artificial joint and a frame member extending from the artificial joint. The frame member is configured for extension over the user's limbs. The exoskeleton device also includes a self - alignment mechanism connected to the frame member. The self - alignment mechanism includes three passive degrees of freedom (pDOF) provided in a prismatic - rotational - rotational (PRR) configuration. The self - alignment mechanism also includes a limb attachment member configured to mechanically couple to a portion of the user's limb.

[0010]

[0010] Some embodiments provide a method for facilitating exoskeleton-assisted movement. The method includes placing an exoskeleton device on a user's limb with an artificial joint of the exoskeleton device positioned around a joint of the user's limb. The method also includes applying forces to a first portion and a second portion of the user's limb by the exoskeleton device. The first portion and the second portion of the user's limb are on opposing longitudinal sides of a joint of the user's limb. Further, the method includes compensating for misalignment between the artificial joint and the joint of the user's limb by an auto-alignment mechanism of the exoskeleton device. The auto-alignment mechanism is positioned around the first portion of the user's limb and the auto-alignment mechanism includes three passive degrees of freedom (pDOF) provided in a prismatic-rotational-rotational (PRR) configuration. The compensation contributes to reducing incorrect forces and / or torques applied to the first portion of the user's limb by the exoskeleton device.

[0011]

[0011] The summary of the invention is provided to introduce in a simplified form a collection of concepts that will be further described below in the detailed description of the embodiments for carrying out the invention. The summary of the invention is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0012]

[0012] To describe the advantages and features listed above and other advantages and features that can be obtained, a more specific description of the subject matter briefly described above is provided with reference to specific embodiments illustrated in the accompanying drawings. It is to be understood that the embodiments are to be further described and explained more specifically and in detail through the use of the accompanying drawings, under the understanding that these drawings depict only typical embodiments and should not be considered as limiting the scope.

Brief Description of the Drawings

[0013]

Figure 1

[0013] A perspective view of exemplary components of an exoskeleton device in a partially extended configuration.

Figure 2

[0014] A perspective view of an exemplary exoskeleton device that is fixed to a user's limbs in a bent configuration.

Figure 3

[0015] A side view of an exemplary self - alignment mechanism of the exoskeleton device.

Figure 4

[0016] Figure 4A is a schematic diagram of how to attach the exoskeleton device to a user's limb. Figure 4B is a schematic diagram of how to attach the exoskeleton device to a user's limb. Figure 4C is a schematic diagram of how to attach the exoskeleton device to a user's limb.

Figure 5

[0017] A block diagram of a control system and a signal processing system associated with the exoskeleton device.

Figure 6A

[0018] A graph of the forces and torques applied to a portion of a user's limb by the exoskeleton device when the self - alignment mechanism is used and when it is not used.

Figure 6B

Figure 6C

Figure 6D

Figure 6E

Figure 6F

Figure 7

Figure 8A

Figure 8B

Figure 8C

Figure 8D

Figure 8E

Figure 8F

Figure 9

Figure 10

[0019] Perspective view of exemplary components of a hip exoskeleton according to the present disclosure.

Figure 11

[0020] Enlarged perspective view of the lower interface of the hip exoskeleton.

Figure 12

[0021] Enlarged perspective view of the upper interface of the hip exoskeleton.

DETAILED DESCRIPTION OF THE INVENTION

[0014] Summary

[0022] The disclosed embodiments are directed to self-aligning mechanisms in passive and powered exoskeletons. Those skilled in the art will understand, from the perspective of the present disclosure, that at least some of the embodiments disclosed herein can address various drawbacks associated with conventional exoskeletons.

[0015]

[0023] For example, the self-aligning mechanisms of the present disclosure use a combination of linear and rotational passive degrees of freedom (pDOFs) and / or elastic elements to dynamically align anatomical and artificial joints. The self-aligning mechanism is configured to transmit torque to the intended joints while reducing undesirable loads on the limbs. In some cases, the range of motion of the pDOFs of the self-aligning mechanisms of the present disclosure is substantially unaffected by differences in the applied assistive torque or by misalignment between the artificial and anatomical joints (e.g., exhibiting insufficient friction in the pDOFs).

[0016]

[0024] An exoskeleton device as described herein can be used to facilitate exoskeleton-assisted movement of a user's limbs. For example, a method for facilitating exoskeleton-assisted movement according to the present disclosure can include various acts such as positioning an exoskeleton device on a user's limbs with the artificial joints of the exoskeleton device positioned around the joints of the user's limbs. Forces can be applied by the exoskeleton device to first and second portions of the user's limbs (the first and second portions of the user's limbs being on opposite longitudinal sides of the joint of the user's limbs). The self-aligning mechanism of the exoskeleton device positioned around the first portion of the user's limb can advantageously compensate for misalignment between the artificial joint and the joint of the user's limb. Such compensation contributes to the reduction of incorrect forces and / or torques applied to the first portion of the user's limb by the exoskeleton device.

[0017]

[0025] For example, in one exemplary implementation of a knee exoskeleton including a self-aligning mechanism according to the present disclosure, at an assist torque of about 50 Nm applied by the knee exoskeleton, the peak incorrect force applied to the user's tibia is less than 10 N (e.g., about 5 N), and the peak incorrect torque applied to the user's tibia is less than 1 Nm (e.g., about 0.5 Nm) (in an experiment from sitting to standing). In contrast, for a knee exoskeleton without a self-aligning mechanism, the peak incorrect force and torque are typically in the ranges of 50 N and 10 Nm, respectively.

[0018]

[0026] The self-aligning mechanisms described herein enable dynamic alignment of the axis of motion and the anatomical axis for various types of user anatomical structures. This allows for an exoskeleton that is likely lighter due to reduced need for customization and fewer individual customization features. Additionally, at least some of the exoskeletons of the present disclosure include substantially symmetric artificial joints and / or frame structures, advantageously allowing the exoskeleton to be used interchangeably on both the right and left limbs (e.g., on the user's right leg or the user's left leg) without hardware modification.

[0019]

[0027] In addition, the self-aligning mechanisms of the present disclosure can be advantageously constructed in a lightweight manner such that they form only a small percentage of the total weight of the exoskeleton. For example, in some implementations, the self-aligning mechanism accounts for less than about 6% (e.g., 5.3%, or 190 g) of the total weight of the exoskeleton (e.g., about 3.6 kg).

[0020]

[0028] Some of the various high-level features and benefits of the disclosed embodiments have been described, but now turn attention to FIGS. 1-12. These figures illustrate various supplementary cases related to the disclosed embodiments.

[0021] Exemplary exoskeleton device

[0029] FIG. 1 illustrates a perspective view of exemplary components of an exoskeleton device 100. The exoskeleton device 100 depicted in FIG. 1 is adapted to selectively apply power and / or torque to a user's knee joint (e.g., to assist an individual with lower limb dysfunction). The exoskeleton device 100 of FIG. 1 may be regarded as a knee exoskeleton, but the principles and techniques described herein may apply to exoskeletons adapted to provide assistance to other body structures (e.g., the waist, elbow, wrist, ankle, and / or other exoskeletons).

[0022]

[0030] In the embodiment shown in FIG. 1, the exoskeleton device 100 includes an artificial joint 102 formed from a first component 102A and a second component 102B. The first component 102A is disposed on the exoskeleton device 100 for positioning on a first lateral side of a human joint (e.g., a human knee), while the second component 102B is disposed on the exoskeleton device 100 for positioning on a second, opposing lateral side of the human joint (see FIG. 2).

[0023]

[0031] As illustrated in FIG. 1, the artificial joint 102 of the exoskeleton device 100 has a pivot point between the thigh region 104 of the exoskeleton device 100 and the tibia region 106 of the exoskeleton device 100. The artificial joint 102 may, in some cases, be formed using a steel shaft and low-friction plastic bushings, and / or other rotating mechanisms. The exoskeleton device 100 may apply an assistive torque to rotate the tibia region 106 relative to the thigh region 104 about the artificial joint 102. In this way, when the exoskeleton device 100 is worn on the user's leg, the assistive torque applies a force to the user's thigh and tibia of the leg, resulting in an assisted rotation of the user's knee around the user's knee joint.

[0024]

[0032] To facilitate such functionality, the exemplary exoskeleton device 100 depicted in FIG. 1 includes a slider-crank mechanism 108 that is connected to the artificial joint 102 and powered by a linear actuator 110. The slider-crank mechanism 108 of FIG. 1 includes separate slider-crank structures that form a four-bar mechanism. For example, as shown in FIG. 1, the separate slider-crank structures include respective cranks 112A, 112B that are also connected to a frame member 114 that is connected to the artificial joint components 102A and 102B. Each crank 112A and 112B is connected to respective sliders 118A, 118B via respective couplers 116A, 116B, and the respective sliders 118A, 118B are connected at respective slider joints 120A and 120B. Each slider joint 120A and 120B is configured to be driven by the linear actuator 110 and to travel along a rail 126 that extends along the thigh region 104 (e.g., along the upper portion of the user's thigh).

[0025]

[0033] The linear actuator 110 can take any suitable form for actuating the slider joints 120A and 120B, such as a reaction force sensing elastic actuator (RFSEA). In some implementations, the actuator uses a ball screw system (e.g., 8×2 mm) in which a nut is driven by a timing belt and supported by two angular contact bearings. The belt pulley system can optionally have a 2.5:1 transmission ratio and can be connected to a brushless DC motor. The actuator can feature a sliding element that acts as a bridge between the actuation system and the ground. This sliding element can be directly moored to the exoskeleton thigh frame and connected to the actuator via two pre-compressed coil springs. The ball screw can be supported by a low friction linear guide that prevents radial load on the ball screw.

[0026]

[0034] The locations of the respective sliders 118A, 118B can impose constraints on the offset of the four-bar mechanism (e.g., the distance between the artificial joint components 102A, 102B and the connection points of the cranks 112A, 112B to the frame member 114). The offset of the four-bar mechanism can be modified to match the thigh dimensions of the intended user and / or user group (e.g., 103 mm for a 50th percentile male thigh).

[0027]

[0035] FIG. 1 illustrates an exoskeleton device 100 in a partially extended configuration. The tibia region 106 of the exoskeleton device 100 can be rotated about the artificial joint 102 relative to the thigh region 104 of the exoskeleton device to a fully flexed position or a fully extended position, or to any position therebetween (e.g., by actuation of the linear actuator 110).

[0028]

[0036] Furthermore, in some implementations, the exoskeleton device 100 includes a flexion stop 122 integrated within the thigh region 104 to limit the range of motion of the linear actuator 110 (e.g., resulting in a maximum flexion knee angle of 100 degrees, or other maximum flexion angle). Still further, in some implementations, the exoskeleton device 100 includes extension stops 124A, 124B integrated on the frames of the thigh region 104 and the tibia region 106 to prevent the artificial joint 102 (and any attached anatomical joint) from hyperextending.

[0029]

[0037] FIG. 1 also illustrates that the exoskeleton device 100 can include an electronic device 128 (the function and structure of which are described hereinafter).

[0030]

[0038] FIG. 2 illustrates a perspective view of the exoskeleton device 100 secured to a user's limb (in a partially flexed configuration). The user's limb shown in FIG. 2 includes the user's right leg 202. As is apparent from FIG. 2, the linear actuator 110 is configured to be secured over the thigh 204 of the user's right leg 202.

[0031]

[0039] For example, FIG. 2 shows a linear actuator 110 that is affixed to the shell 206 of the exoskeleton device 100. The shell 206 can comprise a flexible plastic molded thigh shell that can be flexible enough to allow users with different thigh sizes and / or shapes to use the exoskeleton device 100 in a comfortable manner. In some implementations, the inner surface of the shell 206 is lined with a hook-and-loop fastener (e.g., Velcro®) or other fasteners that allow the shell 206 to connect to the hip strap 208. The hip strap 208 of FIG. 2 can wrap around the user's waist and thigh (e.g., under the shell 206) and be affixed to the shell 206 to improve the physical connection between the exoskeleton device 100 and the user.

[0032]

[0040] In some implementations, the shell 206 comprises one or more additional or alternative straps 210 to facilitate quick donning of the exoskeleton device 100. For example, the shell 206 can include straps 210 having a spin buckle system and / or a magnetic buckle to facilitate quick attachment of the shell 206 to the user's thigh 204.

[0033]

[0041] FIG. 2 also shows that the exoskeleton device 100 can be constructed from various frame members. For example, FIG. 2 illustrates a thigh frame 212 that extends from the terminus of a rail 126 that guides slider joints 120A and 120B. The thigh frame 212 extends towards the prosthetic component 102A. FIG. 2 illustrates only a single portion of the thigh frame 212 that extends towards the user's knee over the right portion of the user's right leg 202, but the thigh frame 212 can include an opposing portion that extends over the left portion of the user's right leg 202 (see FIG. 1).

[0034]

[0042] FIG. 2 further depicts the frame member 114 of the exoskeleton device 100. In particular, FIG. 2 shows the frame member 114 extending from the artificial joint 102 (or from the artificial joint components 102A and 102B) over the tibia 214 of the user's right leg 202. In this regard, the artificial joint 102 may, in some cases, be regarded as the interface between the frame member 114 and the thigh frame 212.

[0035]

[0043] In the exemplary implementation depicted in FIG. 2, the frame member 114 includes a bridging element 216 that is connected to both of the artificial joint components 102A and 102B at different ends of the bridging element 216 (in addition to being connected to the respective cranks 112A and 112B). The bridging element 216 extends around the user's leg 202 towards the central portion 218 of the bridging element 216 from the different artificial joint components 102A and 102B (e.g., in a C shape). FIG. 2 further illustrates a lower link 220 extending from the central portion 218 of the bridging element 216 over and along the tibia 214 of the user's right leg 202.

[0036]

[0044] FIG. 2 illustrates a self - alignment mechanism 222 attached to the lower link 220. The self - alignment mechanism 222 includes a limb attachment member 224 configured to mechanically couple to the tibia 214 of the user's right leg 202, which is on the opposite longitudinal side of the knee joint of the right leg 202 with respect to the thigh of the right leg 202 where the linear actuator is fixed to the right leg 202.

[0037]

[0045] Further details of the self - alignment mechanism 222 are provided hereinafter with reference to FIG. 3, which illustrates a side view of an exemplary self - alignment mechanism 222 of the exoskeleton device 100. As described above, the self - alignment mechanism 222 is connected to the lower link 220 extending from the bridging element 216 of the frame member 114.

[0038]

[0046] Figure 3 illustrates that in some implementations, the self-aligning mechanism 222 can be provided with three passive degrees of freedom (pDOF) of a linear - rotation - rotation (PRR) configuration. The three pDOF of the self-aligning mechanism 222 are, in some cases, integrated in series with one active rotational DOF of knee flexion / extension facilitated by the articulation 102 as described above.

[0039]

[0047] In one example, the linear pDOF of the self-aligning mechanism 222 is formed by a linear guide 302 connected to the lower link 220. The linear guide 302 can comprise a low-friction linear guide of various specifications (e.g., a weight of about 150 g, a range of motion (ROM) of about 750 mm, etc.). The directions associated with the linear pDOF are illustrated by arrows 304A and 304B in Figure 3, indicating that the linear guide 302 can slide along the lower link 220 as represented in Figure 3.

[0040]

[0048] In the example illustrated in Figure 3, the first rotational pDOF of the self-aligning mechanism 222 is formed by a rotational joint 306 connected to a linear guide (which is slidably connected to the lower link 220). The rotational joint 306 can be formed in any suitable manner and can, in some cases, comprise a multi-turn joint without mechanical stops (although mechanical stops can be implemented in some embodiments). The rotational directions associated with the first rotational pDOF are represented by arrow 308 and the axis of rotation 310 in Figure 3, which indicates rotation about the parasagittal plane of the user when the exoskeleton device 100 is worn on the user's leg.

[0041]

[0049] 3 further illustrates that, in some cases, the second rotational pDOF of the self-aligning mechanism 222 is formed from a rotational element 312 (comprising a first component 312A and a second component 312B) connected to the rotational joint 306. For example, FIG. 3 illustrates a shin cuff 314 that connects to the rotational joint 306 at a central portion of the shin cuff 314. The shin cuff 314 also connects to components 312A and 312B of the rotational element 312 at opposite ends of the shin cuff 314, with both components 312A and 312B of the rotational element 312 sharing a common axis of rotation 316 (with rotation indicated by arrow 318). In this manner, the rotational element 312 is configured to rotate about the axis of rotation 316 that is perpendicular to the axis of rotation 310 associated with the rotational joint 306, as shown in FIG. 3. For example, the axis of rotation 310 of the revolute joint 306 lies in the parasagittal plane, while the axis of rotation 316 of the revolute element 312 lies in the coronal plane.

[0042]

[0050] 3 illustrates the limb attachment member 224 of the self-aligning mechanism 222 being secured to the rotational element 312. In this manner, the rotational element 312 can be thought of as connecting the limb attachment member 224 to the rotational joint 306. The limb attachment member 224 can be implemented as an adjustable strap that allows for adaptation to different limb anatomies of different users.

[0043]

[0051] In some implementations, the self-aligning mechanism 222 weighs less than 200 g (e.g., 190 g) or weighs less than 6% (e.g., 5.3%) of the total weight of the exoskeleton device 100. At least some aspects of the exoskeleton device 100 described herein contribute significant advantages over existing exoskeleton systems.

[0044]

[0052] For example, Figures 4A-4C are schematic diagrams of different ways in which an exoskeleton system can be attached to a user's limb (e.g., a user's leg). As depicted in Figures 4A-4C, exo is the force applied by the exoskeleton, F his the reaction force of the human limbs. FIG. 4A illustrates a conventional exoskeleton system, where the assist torque element is attached to the user's limbs with the assist torque element disposed laterally to the user's limbs, thereby creating a torsional moment M by the combination of F exo and F h combination.

[0045]

[0053] In contrast to the approach shown in FIG. 4A, at least some implementations of the present disclosure use the mounting configurations shown in FIG. 4B on the tibia, where the force is transmitted to the limb through flexible straps attached to the frames on both sides, and at least some implementations of the present disclosure use the mounting configurations shown in FIG. 4C on the thigh, where the force is transmitted through flexible straps attached to the frame in front of the limb. The configuration illustrated in FIG. 4B is at least partially facilitated by the arrangement of the first component 102A and the second component 102B of the artificial joint offset parasagittally from the joint of the user's limb, while the configuration illustrated in FIG. 4C is at least partially facilitated by the arrangement of the linear actuator 110 aligned parasagittally with the joint of the user's limb.

[0046]

[0054] In this symmetric design configuration depicted in FIGS. 4B and 4C, the assistive exoskeleton force (F exo ) intersects the limb central axis. Thus, it does not generate a torsional moment (M), thereby providing a significant advantage over conventional exoskeleton systems. Thus, the shear stress on the user's skin that can even cause discomfort and pain can be avoided. In addition, the torsion of the exoskeleton frame at the contact point with the user can be avoided by the design configuration depicted in FIGS. 4B and 4C. Thus, the configuration disclosed herein can help the self-aligning mechanism 222 avoid torsion (e.g., which can result from the coupling of the mechanism and generally requires a heavier and bulkier structure and / or increased design complexity).

[0047]

[0055] In some implementations, the symmetric design of the exoskeleton device 100 is facilitated by structuring each segment of the exoskeleton frame from two symmetric halves for wrapping around the user's limbs. The symmetric design can configure the exoskeleton device 100 for attachment to the user's right leg or the user's left leg without significant hardware modification (e.g., the exoskeleton device 100 can be reversibly worn on the user's right leg or the user's left leg). The exoskeleton frame can be machined from any suitable material, such as 7075 aluminum alloy. These halves can be designed to fit any size range of the user (e.g., a 50th percentile adult male resulting in 160 mm and 115 mm respectively in the diameters of the thigh region 104 and the tibia region 106), and / or can be selectively size - adjustable (e.g., by use of spacers).

[0048] Sensors and embedded electronic devices

[0056] FIG. 5 is an exemplary block diagram of a control and signal processing system and / or technology associated with the exoskeleton device 100. The exoskeleton device of the present disclosure can include an array of sensors (e.g., electronic device 128) for accurately controlling human - robot interaction. For example, the exoskeleton device can include an absolute magnetic rotary encoder placed at the artificial / actuated joint of the exoskeleton for estimating the absolute knee joint position. An incremental magnetic rotary encoder positioned on the motor shaft can measure the position of the knee joint and can be used to estimate the motor angular velocity. Additionally, a linear actuator (e.g., RFSEA) can be equipped with a high - resolution rotary absolute encoder that uses a capstan coupling to measure the deflection of a linear spring. The capstan coupling converts the linear displacement resulting from the spring deflection into a proportional angular displacement of an encoder shaft that can be driven by a cable (e.g., a steel cable).

[0049]

[0057] For testing purposes, a six-axis load cell can be integrated within the exoskeleton tibia region to accurately measure the physical interaction between the user and the robot as needed to assess the functionality of the self-aligning mechanism. The six-axis load cell can use off-the-shelf signal amplifiers and custom acquisition boards. Force and torque recordings from the six-axis load cell can be synchronized with the exoskeleton controller using digital signals.

[0050]

[0058] The exoskeleton device can be controlled using a custom embedded system that, in some cases, includes two different processing units that perform secondary functions such as control routines and data logging and Wi-Fi communication. All time-critical routines, such as sensor readings, filtering, joint position, and torque control loops, can be executed at 2 kHz on a 32-bit microprocessor. The microprocessor can communicate with the motor current servo controller using PWM. High-level control loops, data logging, and user communication can be executed on a single-board computer (e.g., at 500 Hz).

[0051]

[0059] The single-board computer can communicate with the microprocessor using SPI. External devices can run a custom GUI for data monitoring and parameter selection purposes and can communicate with the single-board computer using Wi-Fi. The GUI can be used to change control parameters and start / stop data storage. Additionally, the control system can use a 1050 mAh 6-cell lithium polymer battery and / or a 5V regulator to power the processing unit, embedded sensors, and current servo controller. In some implementations, the power consumption is 3.8 W and 3.1 W when Wi-Fi is on and off, respectively. Further, in some implementations, the weight of the embedded electrical system including the battery and protective cover is 1.1 kg.

[0052]

[0060] Figure 5 illustrates an exemplary control system that can be used in conjunction with the illustrated exoskeleton device or other such exoskeleton devices that incorporate a self-aligning mechanism. At a high level, a control device based on a finite state machine defines a desired knee torque. At a high level, a closed-loop torque control device with a disturbance observer defines a desired motor current to be imposed later using a current driver. The raw signals are processed in an embedded electronics device to estimate the angular position and torque at the knee joint.

[0053]

[0061] A block diagram of the sensor processing is shown in FIG. 5. At startup, an absolute encoder (θ joint ) estimates the absolute position (x0) of the slider using inverse kinematics of a four-bar linkage.

Number

Number

Number

Number

Number

Number

[0054]

[0062] At low levels, a closed-loop controller is used to accurately track the desired knee-space torque

No.

No.

No.

No.

No.

[0055]

[0063] External forces and torques are treated as disturbances and fed into the system as inputs to compensate for the observed torques that do not occur from the modeled system using a feedforward filter (Q FF ) and a feedback filter (Q). Finally, the desired motor torque

No.

[0056]

[0064] At a high level, the torque-angle relationship based on sound biomechanics is simply a function of knee joint position (θ joint Desired knee torque during the sit-to-stand transition as a function of

number

[0057] Exemplary results

[0065] Figures 6A - 9 are graphs of the forces and torques applied to a portion of a user's limb by an exoskeleton device when using and not using a self - alignment mechanism. In particular, the graphs represented by FIGS. 6A - 9 were obtained according to an experimental protocol using an exoskeleton device 100 as described herein. The experimental protocol included the following two tasks: (i) standing up while assisted by the exoskeleton, and (ii) tracking a desired position with respect to a virtual impedance field generated by a powered exoskeleton. Both tasks were performed by the subject using the self - alignment mechanism in a "locked" configuration (with translational / rotational degrees of freedom (DOFs) of the self - alignment mechanism restricted) and using the self - alignment mechanism in an "unlocked" configuration (with translational / rotational DOFs of the self - alignment mechanism not restricted).

[0058]

[0066] The results show that a self - alignment mechanism (e.g., self - alignment mechanism 222 as discussed above) significantly reduces the incorrect forces and torques on the user for both tasks. The results of the experimental protocol also demonstrated an increased level of user comfort facilitated by the reduction of incorrect forces and torques. These results demonstrate the effectiveness of the self - alignment mechanism in improving comfort and performance between the sit - to - stand task and the position - tracking task using a powered knee exoskeleton.

[0059]

[0067] The mass of the self - alignment mechanism not considered in the theoretical model has a significant negative impact on its function. For example, gravity can slide the linear DOF of the self - alignment mechanism to reach its mechanical end - point, substantially impairing the self - alignment function. Similarly, internal forces and torques due to the mass of the self - alignment mechanism can move its passive joints during activity. These unmodeled and uncontrolled movements can potentially limit the reduction of incorrect forces and torques and cause discomfort to the user. Therefore, using a relatively small mass for the self - alignment mechanism as described herein (e.g., about 190 g, about 5.3% of the overall exoskeleton mass, etc.) contributes to the observed improvements in comfort and performance.

[0060]

[0068] Reducing the mass of the self-aligning mechanism without impairing its function during loading is associated with many challenges, especially since the passive joints of the self-aligning mechanism must be able to move freely while transferring the assist torque. For example, a linear joint / pDOF must be able to slide freely while transferring a force F so that the powered exoskeleton can provide assistive and restrictive torques at the user's knee joint (see Fig. 6C). In some implementations, a relatively large linear guide 302 is used (150 g, 3.5 kN maximum load). Smaller and lighter linear guides reduce the overall mass, but they can increase friction, which can impair the movement of the passive joints during loading. z In particular, the symmetric design of the powered exoskeleton as discussed above has a beneficial effect on the function of the self-aligning mechanism. The symmetric design minimizes the torque on the linear guide and allows both the mass and friction of the self-aligning mechanism to be minimized. Similarly, the symmetric design reduces the loads that the link mechanism of the self-aligning mechanism must withstand. This load reduction is beneficial because deformations in the link mechanism of the self-aligning mechanism can impair the ability of its passive joints to move freely during loading.

[0061]

[0069]

[0062]

[0070] ​The comfort and outcomes between each experimental condition were assessed using questionnaires filled out by the subjects at the end of each test (i.e., the standing task and the tracking task with the exoskeleton device in the locked and unlocked configurations). The results show that the presence of the self - alignment mechanism significantly improves comfort between both the standing task and the tracking task. Interestingly, the tracking task was reported to be significantly more comfortable than the standing task. This result can be explained by the fact that incorrect forces and torques were greater during the standing task than during the tracking task. Thus, these results suggest that there is a correlation between incorrect forces and torques and user comfort. The results suggest that these interaction forces and torques were large enough for the subjects to feel lower comfort when using the locked configuration than when using the unlocked configuration.

[0063]

[0071] The performance during the standing task was assessed using the root mean square error of the mean between the center of pressure (CoP) and the mid - line of the force plate on the self - alignment mechanism and the maximum deviation of the CoP from the mid - line. The results show that both performance metrics were significantly better (up to 32%) in the presence of the self - alignment mechanism (i.e., in the unlocked configuration). The performance during the tracking task was assessed using the RMS error between the target wave and the measured knee angle. The RMS error was significantly lower (38%) in the non - configured configuration than in the locked configuration.

[0064]

[0072] Figures 6A - 6F illustrate the average values of the interaction forces and torques between the subject's tibia and the exoskeleton device during the sit - to - stand (STS) task with the exoskeleton device in the locked and unlocked configurations. Figure 7 provides bar plots of the absolute values of the average forces and torques for the STS task for both the locked and unlocked configurations, with error bars indicating the standard error. Similarly, Figures 8A - 8F illustrate the average values of the interaction forces and torques between the subject's tibia and the exoskeleton device during the tracking (TRK) task with the exoskeleton device in the locked and unlocked configurations. Figure 9 provides bar plots of the absolute values of the average forces and torques for the TRL task for both the locked and unlocked configurations, with error bars indicating the standard error.

[0065]

[0073] As is clear from FIGS. 6A - 9, the averages of F y and F z are similar for both the locked and unlocked configurations during the standing - up task, but not so for the tracking task. Further, FIGS. 6A - 9 show that during the tracking task, F y and F z appear to follow similar trajectories, but in the unlocked configuration, the data is offset compared to the locked configuration. Such variations in F y and F z between conditions may be caused by the position of the load cell relative to the active joints of the powered exoskeleton, which can change when the self - alignment mechanism is in the unlocked condition since the load cell can slide along the frame of the exoskeleton. Interestingly, during the standing - up task, the average value of F z is slightly higher when in the unlocked configuration than when in the locked configuration. In the unlocked configuration, only F z contributes to generating the desired flexion / extension torque on the user's knee. In contrast, in the locked configuration, both F z and T y contribute to transferring the knee flexion / extension torque to the user's knee, indicating the possibility of a more pure transfer of torque between the exoskeleton and the human limb during the unlocked configuration.

[0066]

[0074] The results shown in FIGS. 6A - 9 indicate that the presence of a self - alignment mechanism (i.e., the unlocked configuration) can result in a significant decrease in the average values of F x , T y , and T z between both the standing - up task and the tracking task. This reduction is at least partially facilitated by a self - alignment mechanism implemented in an exoskeleton device having three pDOFs that enable translational movement along a first axis and rotational movement about two additional axes that are perpendicular to each other. These results indicate that the proposed self - alignment mechanism has a significant effect against incorrect forces and torques. In different specific kinematic or mechanical implementations, the self - alignment mechanism can be used to achieve similar comfort and performance improvements, provided that it can show a similar reduction in incorrect forces and torques.

[0067] Additional embodiments

[0075] As shown above within this specification, the self - alignment mechanism can be implemented in various types of exoskeleton devices and is not limited to knee exoskeletons. For example, FIG. 10 illustrates a hip exoskeleton 1000 that includes a lower interface 1002 for connection to a user's thigh and an upper interface 1004 for connection to a user's hip. The lower interface 1002 includes a thigh cuff 1006 (e.g., formed from rigid plastic and nylon straps) and an elastic element 1008 (e.g., thick surgical rubber) for securing to the user's thigh (e.g., forming a thigh orthosis). The thigh orthosis distributes the resultant force over a majority of the distal thigh and may include a load - distributing bar 1016.

[0068]

[0076] The upper interface 1004 includes a mounting member 1010 configured to connect to a pelvic pad (not shown) that wraps around the user's buttocks (e.g., forms a pelvic shaping device). The pelvic shaping device may include separate elements for attachment to both sides of the user's pelvis. The separate elements may be connected by straps (e.g., spin buckle straps). The pelvic shaping device may include a torsion-resistant rod that resists independent movement of the pelvic shaping device and transfers sagittal plane moments to the sacral and lumbar portions of the lower back. The torsion-resistant rod may also house an electronic device and / or battery for the hip exoskeleton 1000.

[0069]

[0077] The hip exoskeleton 1000 includes an artificial joint 1012 configured to be positioned around the user's hip to provide an active DOF for facilitating the application of assistive torque to the user's hip.

[0070]

[0078] The hip exoskeleton 1000 of FIG. 10 utilizes an offset slider-crank mechanism 1014 to facilitate assistive torque. In some implementations, the offset slider-crank mechanism 1014 may be powered by a linear actuator (e.g., including a brushless DC motor and a primary spur gear transmission) coupled to a high-efficiency ball screw. A linear guide may support the vertical load on the ball screw nut. Angular contact ball bearings may support the radial and axial loads on the spur gear, and the translational movement of the screw nut and linear guide block along the rail may be converted into rotation of the actuated artificial joint 1012 through a composite compliant rod, creating a series elastic actuator. Lightweight, low-friction dry bushings may support the load on the actuated artificial joint 1012.

[0071]

[0079] Figure 11 illustrates an enlarged view of the lower interface 1002 of the hip exoskeleton 1000. As illustrated in Figure 11, the lower interface 1002 includes a self-aligning mechanism 1102 to facilitate reduction in incorrect forces and torques that would be applied to the user's hip. In particular, the self-aligning mechanism 1102 comprises one or more rails 1104 to which one or more linear guides 1106 are attached (e.g., corresponding rails and linear guides on multiple sides of the shaft 1110 of the hip exoskeleton 1000), providing a linear pDOF (with the directionality indicated by arrows 1108A and 1108B).

[0072]

[0080] The self-aligning mechanism 1102 also includes a rotational pDOF provided by a rotary joint 1112 connected to the thigh cuff 1006 to facilitate passive rotation of the thigh cuff 1006 about an axis that is perpendicular to the translational axis associated with the linear pDOF and coupled to one or more of the linear guides 1106 (shown by axis 1114 and arrow 1116 in Figure 11). The self-aligning mechanism 1102 contributes to reduction in incorrect forces and torques applied by the hip exoskeleton 1000 to the user's body.

[0073]

[0081] Figure 12 illustrates an enlarged view of the upper interface 1004 of the hip exoskeleton 1000. In particular, Figure 12 illustrates that the upper interface 1004 may comprise a separate self-aligning mechanism 1202 that includes a pair of rotational pDOFs formed by separate rotary joints 1204A and 1204B and is configured in series with the active DOF of the artificial joint 1012. The pDOFs of the self-aligning mechanism 1202 may allow for unconstrained hip abduction and / or adduction. The pair of rotational pDOFs rotate about parallel rotational axes 1206A and 1206B (shown by arrows 1208A and 1208B). The self-aligning mechanism 1202 contributes to reduction in incorrect forces and torques resulting from any misalignment between the powered flexion / extension axis of the hip exoskeleton 1000 and the user's anatomical flexion / extension axis, particularly in combination with the self-aligning mechanism 1102.

[0074]

[0082] The following provides an overview of exemplary sensing and power electronics that may be implemented with the hip exoskeleton 1000. The hip exoskeleton 1000 may include a power source such as a 1200 mAh, 6-cell lithium ion (LiIon) battery. A 5V regulator may be implemented to scale the supply voltage as needed to power the embedded computer and analog sensors. A 3.3V regulator may power the microcontroller and operate as the logic voltage for digital sensors. Two separate processing units may be implemented on the motherboard to execute control routines as well as secondary functions such as data storage and Wi-Fi communication. All time-critical routines such as sensor readout, filtering, joint position, torque control loops, etc. may be executed at 1Khz on a microcontroller (e.g., a 32-bit microcontroller). The microcontroller may use pulse width modulation (PWM) to communicate with two motor servo drives that execute closed-loop motor current control at 50kHz.

[0075]

[0083] The microcontroller can communicate with an embedded single-board computer that can execute embedded sensors and high-level control loops, data storage, and user communication (e.g., at 500 Hz) using a dedicated Serial Peripheral Interface (SPI) bus. The embedded single-board computer can communicate with remote devices using Wi-Fi. The remote device can execute a custom graphical user interface (GUI) for data monitoring and parameter selection purposes. Using the GUI, the user can modify high-level control parameters while the device is operating. The operating system for the embedded computer can be stored on a single SD card that can also be used for data storage. The microprocessor, embedded single-board computer, motor servo drive, and voltage regulator can be integrated on a custom motherboard. The electrical system, including the power supply, can be completely enclosed within a custom protective cover that can be connected to the back of the pelvic interface. In some implementations, the power consumption is 3.6 W and 3.1 W when Wi-Fi is on and off, respectively.

[0076]

[0084] The sensor circuit board can be housed within the hip exoskeleton frame. A 14-bit magnetic absolute encoder board can measure the hip flexion / extension angle and can be located at the proximal end of the carbon fiber frame. An Inertial Measurement Unit (IMU) board can measure acceleration and rotational speed and can be located at the distal end of the carbon fiber frame. Both custom circuit boards can communicate with the microcontroller using SPI. A dedicated shielded wire can be used to transmit digital data from the sensors to the motherboard. An incremental encoder can be used to measure the position of the motor shaft for torque control purposes. Hall sensors embedded in the motor can be used for commutation by the servo drive. Signals from the incremental encoder and Hall sensors can be transmitted to the motherboard using a dedicated shielded wire. Another cable carrying the motor power stage current can connect the exoskeleton to the motherboard.

[0077]

[0085] The hierarchical control device can provide simultaneous assistance during walking motion. At a high level, an Adaptive Oscillator (AdOsc) can estimate the walking rhythm of the coupled human-exoskeleton system. The rhythm estimation can be combined with information regarding the start of the walking cycle to provide a continuous estimation of the walking cycle development (e.g., 0 - 100% stride completion). The peak of the hip extension angle is used as the start of the walking cycle.

[0078]

[0086] A finite state machine can detect the peak of the hip flexion angle indicating the start of the walking cycle. The finite state machine can include two states, peak flexion and swing preparation / initiation, and the state machine can take as inputs the angular orientation and velocity of the thigh in the sagittal plane. These input variables can be estimated by a complementary filter that combines accelerometer and gyroscope data from an IMU. A low-pass filter can be applied to the thigh orientation to reduce noise and increase robustness. In particular, the delay introduced by the filter can account for when adjusting the timing of assistance. When the thigh orientation is higher than a predefined threshold (e.g., the hip joint is flexed) and the thigh velocity is lower than a predefined negative threshold (e.g., the thigh is extending), the finite state machine can transition between the peak flexion state and the swing preparation / initiation state. This transition indicates that a suitable peak of hip flexion has been detected and triggers the start of the walking cycle. From the swing preparation / initiation state, the finite state machine can transition back to the peak flexion state when the thigh orientation is lower than a predefined threshold (i.e., the hip joint is extended).

[0079]

[0087] The powered hip exoskeleton 1000 can be used in a bilateral or unilateral configuration, and the two actuation modules can be interchangeable. Each actuation module can have a dedicated finite state machine and an adaptive oscillator. When the exoskeleton is used bilaterally, the user can have the option of using a dedicated finite state machine and an adaptive oscillator for each actuation module. In this case, the modules are controlled independently of each other using their own percent stride estimation to generate assistance. Alternatively, the user can have the option of selecting the finite state machine and adaptive oscillator of one actuation module to control both actuation modules. If the user chooses to use the finite state machine and adaptive oscillator from only one actuation module, the desired torque for the contralateral site can be delayed by 50% of the stride. The latter option can be used, for example, when a hemiplegic subject uses the non-affected side to control the movement of the affected side.

[0080]

[0088] The mid-level controller defines the desired assistance torque based on the gait phase estimation (e.g., percent stride) received from the high-level controller. The desired assistance torque is defined using two Gaussian functions, one for flexion and one for extension. Each Gaussian function can include three parameters that can be adjusted by the user through a graphical user interface.

Number

[0081]

[0089] The first parameter is the peak of the torque (i.e., T flx , T ext ). The second parameter is the timing of the peak of the torque at which the torque peak occurs (i.e., t flx , t ext ), or percent stride. The third parameter is the width of the Gaussian function (i.e., w flx , w extIt is the duration of assistance that is adjusted by varying ). The desired torque obtained by the Gaussian function can then be scaled by the user's body mass index. The user has the option of using different parameters on the left and right sides of the powered hip exoskeleton or the same parameters.

[0082]

[0090] The low-level controller converts the desired assistance torque into the desired motor torque for the servo motor. The torque controller may include a feedforward command based on a position-dependent transmission ratio. This feedforward command may include a constant coefficient (η) that compensates for the efficiency of the actuation system. Additionally, two compensators may be implemented to correct for the dynamic effects of the transmission system on the output torque that increase fidelity and reduce apparent impedance at the output joint. Both compensators may take as input the motor position measured by an incremental encoder. The first compensator may generate an online estimate of the viscous torque due to the linear actuator velocity. The second compensator may compute a scaled and low-pass filtered estimate of the transmission inertia. The desired current can be calculated by first adding the feedforward term to the compensator estimates and then dividing by the torque constant of the motor.

[0083]

[0091] Walking, running, and ascending stairs are periodic activities, but the kinematic profiles are different. The periodicity of each activity may enable AdOsc to learn the frequency of each task, and the state machine parameters may be further adjusted to fit the kinematics. Additionally, the peak assistance and timing are different for walking, running, and stairs. However, the high-level control algorithm may not fundamentally change between user activities in some cases. Therefore, a set of parameters can be adjusted for each of the tasks so that the desired assistance profile can be reliably generated.

[0084] Further exemplary aspects

[0092] Embodiments of the present disclosure may include the features listed in the following clauses, but are not necessarily limited thereto.

[0085]

[0093] Clause 1: An exoskeleton device comprising an artificial joint, a frame member extending from the artificial joint configured for extension over a user's limb, and a self-aligning mechanism connected to the frame member, the self-aligning mechanism comprising three passive degrees of freedom (pDOF) provided in a linear-rotation-rotation (PRR) configuration, the self-aligning mechanism comprising a limb attachment member configured to mechanically couple to a portion of the user's limb.

[0086]

[0094] Clause 2: The exoskeleton device according to Clause 1, wherein the artificial joint comprises a first component and a second component, the first component and the second component being configured to be positioned on opposing lateral sides of a joint of the user's limb.

[0087]

[0095] Clause 3: The exoskeleton device according to Clause 2, wherein the frame member comprises a bridging element, the bridging element being connected to both the first component and the second component at opposing ends of the bridging element, the frame member comprising a lower link extending from a central portion of the bridging element, the lower link being configured to extend along the user's limb.

[0088]

[0096] Clause 4: The exoskeleton device according to Clause 3, wherein the linear pDOF of the self-aligning mechanism is formed by a linear guide connected to the lower link.

[0089]

[0097] Clause 5: The exoskeleton device according to Clause 4, wherein the first rotational pDOF of the self-aligning mechanism is formed by a rotary joint connected to a linear guide slidably connected to the lower link.

[0090]

[0098] Clause 6: In the exoskeleton device according to Clause 5, the second rotational pDOF of the self-aligning mechanism is formed by a rotating element connected to the rotary joint, and the rotating element is configured to rotate around a second rotation axis that is perpendicular to the first rotation axis associated with the rotary joint. Exoskeleton device.

[0091]

[0099] Clause 7: In the exoskeleton device according to Clause 6, the limb attachment member is connected to the rotating element. Exoskeleton device.

[0092]

[0100] Clause 8: In the exoskeleton device according to any one of Clauses 1 to 7, the self-aligning mechanism weighs less than 200 g. Exoskeleton device.

[0093]

[0101] Clause 9: In the exoskeleton device according to any one of Clauses 1 to 8, the self-aligning mechanism forms less than 6% of the total weight of the exoskeleton device. Exoskeleton device.

[0094]

[0102] Clause 10: In the exoskeleton device according to any one of Clauses 1 to 9, the artificial joint is connected to a slider-crank mechanism, and the slider-crank mechanism is powered by a linear actuator. Exoskeleton device.

[0095]

[0103] Clause 11: In the exoskeleton device according to Clause 10, the artificial joint includes a first component and a second component configured to be positioned on opposite lateral sides of a joint of the user's limb, and the slider-crank mechanism includes a four-bar mechanism. The four-bar mechanism includes a first slider-crank structure connected between the linear actuator and the first component of the artificial joint, and a second slider-crank structure connected between the linear actuator and the second component of the artificial joint. Exoskeleton device.

[0096]

[0104] Clause 12: In the exoskeleton device according to Clause 11, the linear actuator is configured for fixation on a second portion of the user's limb, and the second portion is on the opposing longitudinal side of the limb joint with respect to a portion of the user's limb, exoskeleton device.

[0097]

[0105] Clause 13: In the exoskeleton device according to Clause 12, further comprising a shell connected to the linear actuator, and the shell is configured to form around a second portion of the user's limb, exoskeleton device.

[0098]

[0106] Clause 14: In the exoskeleton device according to Clause 13, further comprising a strap connected to the shell and configured to fix the shell to a second portion of the user's limb, exoskeleton device.

[0099]

[0107] Clause 15: In the exoskeleton device according to any one of Clauses 12 to 14, the linear actuator is configured for fixation on a second portion of the limb in a parasagittal alignment with the limb joint of the user, exoskeleton device.

[0100]

[0108] Clause 16: In the exoskeleton device according to Clause 15, the first component and the second component of the artificial joint are configured to be positioned offset parasagittally from the limb joint of the user, exoskeleton device.

[0101]

[0109] Clause 17: In the exoskeleton device according to any one of Clauses 12 to 16, the limb is the user's leg, a portion of the limb is the shin of the leg, the second portion of the limb is the thigh of the leg, and the user's joint is the knee of the leg, exoskeleton device.

[0102]

[0110] Clause 18: In the exoskeleton device according to Clause 17, the exoskeleton device is configured for fixation to the user's right leg, and the exoskeleton device is configured for fixation to the user's left leg, exoskeleton device.

[0103]

[0111] Clause 19: A method for promoting exoskeleton-assisted movement, the method comprising the steps of: disposing an exoskeleton device on a user's limbs with the artificial joints of the exoskeleton device positioned around the joints of the user's limbs; applying forces to a first portion and a second portion of the user's limbs by the exoskeleton device, wherein the first portion and the second portion of the user's limbs are on opposing longitudinal sides of the joint of the user's limbs; compensating for misalignment between the artificial joint and the joint of the user's limbs by an auto-alignment mechanism of the exoskeleton device, the auto-alignment mechanism being positioned around the first portion of the user's limbs and the auto-alignment mechanism comprising three passive degrees of freedom (pDOF) provided in a prismatic-rotary-rotary (PRR) configuration, the compensation contributing to a reduction of incorrect forces and / or torques applied to the first portion of the user's limbs by the exoskeleton device.

[0104]

[0112] Clause 20: The method according to Clause 19, wherein at an assist torque of about 50 Nm applied to the user's limbs by the exoskeleton device, a peak incorrect force applied to the first portion of the user's limbs by the exoskeleton device is less than 10 N, and a peak incorrect torque applied to the first portion of the user's limbs by the exoskeleton device is less than 1 Nm.

[0105] Conclusion

[0113] Certain embodiments of the present disclosure have been described in detail with reference to specific configurations, parameters, components, elements, etc., but this description is illustrative and should not be construed as limiting the scope of the claimed invention.

[0106]

[0114] Furthermore, for any given element of the components of the described embodiments, it should be understood that any of the possible alternatives listed for that element or component may be used generally, individually, or in combination with each other, unless otherwise implied or explicitly stated.

[0107]

[0115] In addition, unless otherwise indicated, any numerical values, components, distances, or other measurements used in this specification and the claims should be understood to be optionally modified by the term "about" or its synonyms. When the terms "about," "approximately," "substantially," or the like are used in conjunction with a stated quantity, value, or condition, they can be taken to mean a quantity, value, or condition that deviates by less than 20%, less than 10%, less than 5%, or less than 1% from the stated quantity, value, or condition. At a minimum, and not as a limitation on the application of the doctrine of equivalents to the claims, each numerical parameter should be construed in light of the reported significant digits and by applying ordinary rounding techniques.

[0108]

[0116] Any headings and subheadings used in this specification are for organizing purposes only and are not intended to limit the description or the claims.

[0109]

[0117] It should also be noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the" do not exclude a plurality of referents unless the context clearly dictates otherwise. Thus, for example, embodiments referring to a singular referent (e.g., "widget") can also include two or more such referents.

[0110]

[0118] It should also be understood that the embodiments described herein can include the properties, features (e.g., components, elements, members, parts, components, and / or portions) described in other embodiments described herein. Thus, the various features of a given embodiment can be combined with and / or incorporated into other embodiments of the present disclosure. Therefore, the disclosure of a particular feature related to a particular embodiment of the present disclosure should not be construed as limiting the application or inclusion of the above features to that particular embodiment. Rather, it is understood that other embodiments can also include such features. [Form 1] An artificial joint, A frame member extending from the artificial joint configured for extension onto a limb of a user, An auto - alignment mechanism connected to the frame member, the auto - alignment mechanism comprising three passive degrees of freedom (pDOF) provided in a prismatic - revolute - revolute (PRR) configuration, the auto - alignment mechanism comprising a limb attachment member configured to mechanically couple to a portion of the user's limb, the auto - alignment mechanism An exoskeleton device comprising the above. [Form 2] The exoskeleton device according to Form 1, wherein the artificial joint comprises a first component and a second component, and the first component and the second component are configured to be positioned on opposite lateral sides of a joint of the user's limb, the exoskeleton device. [Form 3] The exoskeleton device according to Form 2, wherein the frame member comprises a bridging element, the bridging element is connected to both the first component and the second component at opposite ends of the bridging element, the frame member comprises a lower link extending from a central portion of the bridging element, and the lower link is configured to extend along the user's limb, the exoskeleton device. [Form 4] The exoskeleton device according to Form 3, wherein the prismatic pDOF of the auto - alignment mechanism is formed by a linear guide connected to the lower link, the exoskeleton device. [Form 5] The exoskeleton device according to Form 4, wherein the first rotational pDOF of the auto - alignment mechanism is formed by a rotary joint connected to the linear guide slidably connected to the lower link, the exoskeleton device. [Form 6] The exoskeleton device according to Form 5, wherein the second rotational pDOF of the auto - alignment mechanism is formed by a rotating element connected to the rotary joint, and the rotating element is configured to rotate about a second axis of rotation perpendicular to a first axis of rotation associated with the rotary joint, the exoskeleton device. [Form 7] In the exoskeleton device according to Form 6, the limb attachment member is connected to the rotating element, the exoskeleton device. [Form 8] In the exoskeleton device according to Form 1, the self-aligning mechanism weighs less than 200 g, the exoskeleton device. [Form 9] In the exoskeleton device according to Form 1, the self-aligning mechanism forms less than 6% of the total weight of the exoskeleton device, the exoskeleton device. [Form 10] In the exoskeleton device according to Form 1, the artificial joint is connected to a slider-crank mechanism, and the slider-crank mechanism is powered by a linear actuator, the exoskeleton device. [Form 11] In the exoskeleton device according to Form 10, the artificial joint includes a first component and a second component configured to be positioned on opposite lateral sides of the joint of the user's limb, the slider-crank mechanism includes a four-bar mechanism, and the four-bar mechanism a first slider-crank structure connected between the linear actuator and the first component of the artificial joint, and a second slider-crank structure connected between the linear actuator and the second component of the artificial joint and includes, the exoskeleton device. [Form 12] In the exoskeleton device according to Form 11, the linear actuator is configured for fixation on a second portion of the user's limb, and the second portion is on the opposite longitudinal side of the limb joint with respect to the one portion of the user's limb, the exoskeleton device. [Form 13] In the exoskeleton device according to Form 12, it further includes a shell connected to the linear actuator, and the shell is configured to be formed around the second portion of the user's limb, the exoskeleton device. [Form 14] In the exoskeleton device according to Form 13, it further includes a strap connected to the shell and configured to fix the shell to the second portion of the user's limb, the exoskeleton device. [Form 15] In the exoskeleton device according to Form 12, the linear actuator is configured for fixation on the second portion of the user's limb in a parasagittal alignment with the limb joint, the exoskeleton device. [Form 16] In the exoskeleton device according to Form 15, the first component and the second component of the artificial joint are configured to be positioned offset parasagittally from the joint of the limb of the user, the exoskeleton device. [Form 17] In the exoskeleton device according to Form 12, the limbs are the legs of the user, a part of the limbs is the tibia of the leg, a second part of the limbs is the thigh of the leg, and the joint of the user is the knee of the leg, the exoskeleton device. [Form 18] In the exoskeleton device according to Form 17, the exoskeleton device is configured for fixation to the right leg of the user, and the exoskeleton device is configured for fixation to the left leg of the user, the exoskeleton device. [Form 19] A method for promoting exoskeleton-assisted movement, placing the exoskeleton device on the user's limbs with the artificial joint of the exoskeleton device positioned around the joint of the user's limbs; applying a force to a first part and a second part of the user's limbs by the exoskeleton device, wherein the first part and the second part of the user's limbs are on opposite longitudinal sides of the joint of the user's limbs; compensating for misalignment between the artificial joint and the joint of the user's limbs by a self-aligning mechanism of the exoskeleton device, the self-aligning mechanism being positioned around the first part of the user's limbs, and the self-aligning mechanism comprising three passive degrees of freedom (pDOF) provided in a prismatic-rotational-rotational (PRR) configuration, wherein the compensation contributes to reducing an incorrect force and / or torque applied to the first part of the user's limbs by the exoskeleton device. [Form 20] In the method according to Form 19, at an assist torque of about 50 Nm applied to the user's limbs by the exoskeleton device, a peak incorrect force applied to the first part of the user's limbs by the exoskeleton device is less than 10 N, and a peak incorrect torque applied to the first part of the user's limbs by the exoskeleton device is less than 1 Nm, the method.

Claims

1. an artificial joint positioned around a joint of the user's limb; a frame member extending from the artificial joint configured for extension onto a user's limb; a self-aligning mechanism connected to the frame member, the self-aligning mechanism having three passive degrees of freedom (pDOF) provided in a prismatic-revolute-revolute (PRR) configuration, the self-aligning mechanism comprising a limb attachment member configured to mechanically couple to a portion of the limb of the user; Equipped with An exoskeleton device, wherein the artificial joint comprises a first component and a second component, the first component and the second component being configured to be positioned on opposite lateral sides of a joint of the limb of the user, respectively.

2. 2. The exoskeleton device of claim 1, wherein the frame member comprises a bridge element connected to both the first component and the second component at opposite ends of the bridge element, the frame member including a lower link extending from a central portion of the bridge element, the lower link configured to extend along the limb of the user.

3. The exoskeleton device of claim 2 , wherein the linear pDOF of the self-aligning mechanism is formed from a linear guide connected to the lower link.

4. The exoskeleton device of claim 3 , wherein a first rotational pDOF of the self-aligning mechanism is formed by a rotational joint connected to the linear guide, which is slidably connected to the lower link.

5. 5. The exoskeleton device of claim 4, wherein a second rotational pDOF of the self-aligning mechanism is formed by a rotational element connected to the rotational joint, the rotational element configured to rotate about a second rotational axis that is perpendicular to the first rotational axis associated with the rotational joint.

6. The exoskeleton device of claim 5 , wherein the limb attachment member is connected to the rotating element.

7. an artificial joint positioned around a joint of the user's limb; a frame member extending from the artificial joint configured for extension onto a user's limb; a self-aligning mechanism connected to the frame member, the self-aligning mechanism having three passive degrees of freedom (pDOF) provided in a prismatic-revolute-revolute (PRR) configuration, the self-aligning mechanism comprising a limb attachment member configured to mechanically couple to a portion of the limb of the user; Equipped with the artificial joint is connected to a slider-crank mechanism, the slider-crank mechanism being powered by a linear actuator; the artificial joint comprises a first component and a second component configured for positioning on opposite lateral sides of a joint of the limb of the user, the slider-crank mechanism comprising: a first slider-crank structure connected between the linear actuator and the first component of the artificial joint, the first slider-crank structure including a first slider joint configured to be advanced along a rail by the linear actuator, a first slider connected at the first slider joint, and a first crank connected to the first slider via a first coupler and connected to a frame member connected to the first and second components of the artificial joint; a second slider-crank structure connected between the linear actuator and the second component of the artificial joint, the second slider-crank structure including a second slider joint configured to be advanced along the rail by the linear actuator, a second slider connected at the second slider joint, and a second crank connected to the second slider via a second coupler and connected to the frame member connected to the first and second components of the artificial joint; An exoskeleton device comprising:

8. 8. The exoskeleton device of claim 7, wherein the linear actuator is configured to be fixed to the outside of a second portion of the user's limb, the second portion being on the opposite side of the first portion of the user's limb with respect to the joint of the user's limb.

9. 9. The exoskeleton device of claim 8, further comprising a shell connected to the linear actuator, the shell configured to form around the second portion of the user's limb.

10. The exoskeleton device of claim 9 , further comprising a strap connected to the shell and configured to secure the shell to the second portion of the user's limb.

11. 9. The exoskeleton device of claim 8, wherein the limb is the user's leg, the first portion of the limb is the shin of the leg, the second portion of the limb is the thigh of the leg, and the joint of the user is the knee of the leg.

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