Upper-limb exoskeleton
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- IUVO SRL
- Filing Date
- 2025-11-25
- Publication Date
- 2026-06-04
Smart Images
Figure IB2025062058_04062026_PF_FP_ABST
Abstract
Description
UPPER-LIMB EXOSKELETON
[0001] CROSS-REFERENCE TO RELATED PATENTS AND APPLICATIONS
[0002] This application incorporates by reference International Application No. PCT / IB2023 / 052820, published on September 28, 2023, as WO 2023 / 180958 Al; U.S. Patent Publication No. 2023 / 0311297 Al, published October 5, 2023; U.S. Patent No. 11,801,596 B2, published October 31, 2023; U.S. Patent Publication No. 20230373080 Al, published November 23, 2023; International Application No. PCT / IB2023 / 058629, published on March 7, 2024, as WO 2024 / 047581 Al; and International Application No. PCT / IB2023 / 060177, published on April 18, 2024, as WO 2024 / 079632 AL
[0003] FIELD OF DISCLOSURE
[0004] The disclosure relates to a system for a human body in an exoskeleton and for supporting assistive devices adapted to augment an operator’s performance, mitigate repetitive strain injuries, and / or assist in exerting efforts.
[0005] BACKGROUND
[0006] Exoskeletons are useful tools for addressing needs in healthcare and industrial applications. These exoskeletons can give a user improved endurance and stability or provide corrections to an impaired individual's gait by applying mechanical forces to the body in parallel with the user's muscles. These assistive and rehabilitative bionics technologies have the potential to improve quality of life, reduce the incidence of injury, and create a safer, more comfortable, and productive environment. Exoskeletons may be used in other applications, such as in the fitness and exercise domain, whereby the exoskeleton may be arranged to provide restrictive or resistive forces during movement to improve the strength and endurance of a user.
[0007] Conventional upper-limb exoskeletons are designed to vertically support the arms of an operator and assist in tasks that are to be performed in positions where the arms are raised. An exemplary exoskeleton system is arranged for the upper body, including the shoulder and arms, by enhancing performance by reducing forces at the shoulder (e.g., gravitational forces that urge the arms downward) and enabling the user to perform tasks that require shoulder elevation with less effort. The exoskeleton may assist the user in elevating and supporting the user’ s arms and can reduce physical risks and discomfort from tasks carried out above chest height or overhead. While certain exoskeletons are available, several technical issues hinder the practicaluse of exoskeletons in the industry. Specific problems include discomfort for passive and active exoskeletons, the device's weight, alignment with human anatomy and kinematics, and detection of human intention to enable smooth movement for active exoskeletons.
[0008] Many wearable exoskeletons lack a compact, lightweight torque profile that obtains the desired functional requirements for above-chest height and overhead operations. These exoskeletons are often equipped with cumbersome motors, sensors, or actuators and cannot provide a wide range of motion compared to the human upper-limb torso. Moreover, most active exoskeletons supporting shoulder and elbow movements are not portable due to their high power-to-weight ratio. Thus, designing an active, lightweight upper-limb exoskeleton with existing actuator systems is challenging.
[0009] Some arm-supporting exoskeletons have an actuator that couples a spring and line elements at a junction. In some instances, the line elements may partially wrap around a pulley system to compensate for gravitational forces. However, these exoskeletons can exhibit slip problems and do not feature integrated and distinct stoppage elements to control the movement of the spring and compensating elements.
[0010] Conventional upper-limb exoskeletons cannot vary the level of assistance according to different types of input (e.g., user status, context-related information, user decision). Additionally, existing exoskeletons do not provide a variable ‘fixed’ status that can be created between the permitted range of motion for the upper limb. Finally, the exoskeletons of the prior art do not provide both manual and remote options to adjust assistance levels provided by the actuation elements.
[0011] SUMMARY
[0012] The embodiments of this disclosure overcome the disadvantages observed in the prior art and provide exoskeleton solutions arranged to vary the assistance level according to different types of inputs (e.g., user status, context-related information, and user decision). The compensation device can be switched between different conditions (e.g., locked, unlocked, and transparent). Different locked positions of the compensation device can be produced to create conditions of fully fixed support, and the control of switching between the different conditions can be customized.
[0013] An upper-limb exoskeleton has a compensation device, a control system, and a frame connected to the compensation device and control system. The compensation device includesan elastic mechanism within a housing configured to generate assistive torque to assist an operator exerting efforts on a joint axis.
[0014] The compensation device includes a selector system that adjusts its status between an unlock mode, a lock mode, and a transparent mode. Advantageously, the selector system is configured to adjust the status of the compensation device to the lock mode at various positions about the joint axis.
[0015] The selector system features a shaft that rotates about the joint axis by a selector switch and translates along the joint axis to adjust the status between the unlock, lock, and transparent modes. The system includes a spacer cage containing one or more rollers displaced by a radial cam surface of the shaft away from the joint axis against a socket rim of the housing.
[0016] The unlock mode includes one or more rollers remaining within the outer diameter of the spacer cage; the lock mode includes one or more rollers engaging the socket rim. The socket rim includes multiple sockets arranged to lock the compensation device in multiple positions about the joint axis with the full support of the operator’s arm. Each roller of the one or more rollers may vary in size to support predefined engagement with the socket rim in a single position.
[0017] The selector system also includes a ball cage containing one or more balls arranged to contact a vertical cam surface of the selector shaft. The vertical cam surface includes one or more depressions to receive one or more balls when the selector system is in the transparent mode. The transparent mode includes an inhibitor pin of the selector shaft inserted into a spring pin of the first bracket assembly to disable the assistive torque.
[0018] The compensation device includes an active regulation system that preloads a level of assistive torque provided by the elastic mechanism. The system is configured to modify the distance between a first-bracket assembly and a second-bracket assembly. It comprises a servomotor, a worm gearbox, and a cam.
[0019] The control system can be wirelessly connected to a remote controller configured to operate the active regulation system and / or the selector system. The control system comprises a microcontroller configured to control the actuation of the compensation device using an open loop current control by, after receiving a request for a new level of assistive torque, comparing the new level of assistive torque to an actual position of the cam to determine a pulse-width modulation duty cycle as a function of the actual position of the cam and generating a current from a driver to an actuator arranged to rotate the cam with a constant velocity independent of a new position at which a change of the level of assistive torque occurs.
[0020] The microcontroller is further configured to compute instantly delivered torque as the product between the angle about the joint axis and the resulting stiffness of the elastic mechanism using a function of a current level of assistive torque, the status of the compensation device, and the angle about the joint axis. The microcontroller computes the torque for each joint flexion as an integral from onset to the offset of the instantly delivered torque, onset and offset being instants in which the angle about the joint axis is greater and lower, respectively, than a predetermined threshold angle.
[0021] These and other features, aspects, and advantages of the present disclosure will be better understood in the following description, appended claims, and accompanying drawings.
[0022] BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The drawing figures are not necessarily drawn to scale but to provide a better understanding of the components thereof. They are not intended to limit scope but to provide exemplary illustrations. The figures illustrate exemplary configurations of an exoskeleton and in no way limit the structures or configurations according to the present disclosure.
[0024] Fig. 1 is a diagram showing planes and axes of movement.
[0025] Fig. 2 is a schematic diagram of an exoskeleton system according to the disclosure.
[0026] Fig. 3 is a plan view of the first side of a compensation device in the exoskeleton system of Fig. 2 without a portion of a housing.
[0027] Fig. 4 is a diagram illustrating various assistance level profiles.
[0028] Fig. 5A is a perspective cross-sectional view of an active regulation system of the compensation device.
[0029] Fig. 5B is a rear cross-sectional view of the active regulation system of Fig. 5A.
[0030] Fig. 6A is a partial perspective view of the active regulation system.
[0031] Fig. 6B is a perspective cross-sectional view of the active regulation system of Fig. 6A.
[0032] Fig. 7 is a partial side view of various modes of a selector system.
[0033] Fig. 8 is an exploded view of the selector system.
[0034] Fig. 9 is a cross-sectional view of the selector system
[0035] Fig. 10 is a perspective view of a selector shaft for the selector system.
[0036] Figs. 11A and 11B are partial side views of the selector system in disengaged and engaged positions of the rollers.
[0037] Fig. 12 illustrates the force distribution of the selector system in Fig. 1 IB.
[0038] Figs. 13A and 13B are partial side views of an alternative embodiment of the selector system.
[0039] Fig. 14 is a cross-sectional view of the selector system in an engaged configuration.
[0040] Fig. 15 illustrates a counter-cam profile for a selector system.
[0041] Figs. 16A and 16B are cross-sectional views of the compensation device in disengaged and engaged positions of the selector system.
[0042] Fig. 17 is a schematic drawing of a control system for the exoskeleton system.
[0043] Fig. 18 is a flowchart of actuation control by the control system.
[0044] Fig. 19 illustrates a flowchart for computing instantly delivered torque.
[0045] DEFINITIONS
[0046] The disclosed embodiments of an exoskeleton and components for use therewith, as well as the interior and exterior portions of the exoskeleton, may be described independently for ease of understanding. The interior and exterior portions of the exoskeleton function together to support a user’s exerting efforts.
[0047] Fig. 1 exemplifies various planes and axes of movement used to identify the relative positions of body parts or their relationships.
[0048] As used, the term “proximal” has its ordinary meaning and refers to a location next to or near the point of attachment or origin or a central point or located toward the center of the body. Likewise, the term “distal” has its ordinary meaning and refers to a location situated away from the point of attachment or origin or a central point or located away from the center of the body.
[0049] Medial is toward the body's midline or the median or sagittal plane (SP), which splits the body head-to-toe into two halves, the left and right. Lateral is the side or part of the body that is away from the middle. For example, for a leg, the medial side is on the inside of the exoskeleton, and the lateral side is on the outside of the device relative to the median plane.
[0050] The coronal or frontal plane (CP) divides the body into posterior (P) and anterior parts (A) and is perpendicular to the sagittal plane (SP). The term “posterior” also has its ordinary meaning and refers to a location behind or at another location's rear. The term “anterior” has its ordinary meaning and refers to a location ahead of or in front of another location.
[0051] The transverse or horizontal plane (HP) divides the body into superior and inferior parts and may be considered relative to the ground (G).
[0052] Therefore, the term “frontal plane” has its ordinary meaning and refers to a plane extending through a body to divide the body into the front or anterior and back or posterior halves. The term “sagittal plane” has an ordinary meaning and refers to a plane extending through a body to divide the body into left and right halves, as in the mid-sagittal plane referenced above. The term “transverse plane” has its ordinary meaning and refers to a plane extending through a body to divide the body into the top or upper and bottom or lower halves.
[0053] Movement at the joints takes place in a plane about an axis, and there are three axes of rotation, including the sagittal axis (SA), the lateral axis (LA), and the vertical axis (VA). The sagittal axis passes horizontally from posterior to anterior and is formed by the intersection of the sagittal and transverse planes. The lateral axis passes horizontally from left to right and is formed by the intersection of the frontal and transverse planes. The vertical axis passes vertically from inferior to superior and is formed by the intersection of the sagittal and frontal planes.
[0054] Flexion and extension are movements that occur in the sagittal plane. They refer to increasing and decreasing the angle between two body parts: flexion is a movement that decreases the angle between two body parts. Extension refers to a movement that increases the angle between two body parts. Abduction is a movement away from the midline - just as abducting someone is to take them away. Adduction is a movement toward the midline.
[0055] The terms “rigid,” “flexible,” “compliant,” and “resilient” may distinguish characteristics of portions of certain features of the interface system. The term “rigid” should denote that an element of the exoskeleton, such as a frame, is generally devoid of flexibility. Within the context of " rigid features,” it should indicate that they do not lose their overall shape when force is applied and may break if bent with sufficient force. The term “flexible” should denote that features are capable of repeated bending such that the features may be bent into retained shapes or the features retain no general shape, but continuously deform when force is applied.
[0056] The term “compliant” may qualify such flexible features as generally conforming to the shape of another object when placed in contact therewith, via any suitable natural or applied forces, such as gravitational forces, or forces applied by external mechanisms, for example, strap mechanisms. The term “resilient” may qualify such flexible features as generallyreturning to an initial general shape without permanent deformation. As for the term “semirigid,” this term may connote properties of support members or shells that provide support and are free-standing; however, such support members or shells may have flexibility or resiliency.
[0057] The term “control system” describes a main circuit board configured to provide power and a suitable electronic interface for the wired connections of all involved sensors. The control system is part of an electronic platform that supports bidirectional communication with external systems.
[0058] The term “encoder” is understood to have its ordinary and usual meaning to one skilled in the art, and, unless specified, may refer to absolute and incremental encoders. The encoder may encompass a device or sensor used to detect positional information. The encoder may be mechanical, optical, magnetic, or electromagnetic induction type.
[0059] The term “microcontroller” or “computing unit” refers to one or more devices, circuits, or processing cores configured to process data, such as computer program instructions, and includes personal computers, desktop computers, laptop computers, message processors, handheld devices, multi-processor systems, microprocessor-based or programmable consumer electronics, network PCs, minicomputers, mainframe computers, mobile telephones, PDAs, tablets, pagers, routers, switches, and the like.
[0060] The term “sensor” is understood to have its ordinary and usual meaning to one skilled in the art. The sensor may be a device that measures a physical quantity or quality and converts the measurement into electrical signals that can be read, analyzed, stored, and / or understood by a user, clinician, or another instrument. Additionally, the term “sensorized” is understood to mean fitted or embedded with one or more sensors. The described mechanisms can be sensorized to measure or estimate the torque provided to the user and the arm angle (and derived parameters).
[0061] The term “user” refers to a person who uses the exoskeleton. The user may be a patient or an operator. The term “clinician” refers to a clinical specialist, supervisor, therapist, doctor, or person with a similar role that assists or oversees the operation of the exoskeleton by the user.
[0062] The term “transparent mode” describes a compensation device mode that provides neither obtrusive nor assistive exoskeleton action. The zero-torque modality means that approximately zero newton-meters, or less than 0.57 N m, of torque, is applied along the full range of shoulder flexion angles.
[0063] The embodiments of the disclosure are adapted for a human body and may be dimensioned to accommodate different types, shapes, and contours of human body sizes. For explanatory purposes, the upper-limb exoskeleton embodiments described correspond to different body sections and are denoted by general anatomical terms for the human body.
[0064] The embodiments of the upper-limb exoskeleton system may correspond to anterior and posterior body sections defined by an anterior-posterior plane. The anatomical terms described are intended to maintain the normal understanding of such terms as readily understood by one of ordinary skill in the art of orthopedics, braces, human interfaces, and supports.
[0065] DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS
[0066] Fig. 2 shows an exoskeleton 100 from a perspective view according to the present disclosure. The exoskeleton 100 comprises a compensation device 102 carried by or supported on a frame 106 to be worn by an operator. The compensation device 102 is arranged to compensate for resistive moments acting on a joint during the operator's efforts, such as the effects of gravity pulling the operator's arms down. In embodiments, the compensation device 102 may comprise a separate or distinct unit arranged at each operator's arm and generally at the operator's upper arm or shoulder. In other embodiments, the compensation device 102 may be arranged centrally at the operator's back or other locations. The compensation device 102 may function to assist an operator in exerting efforts, such as but not limited to raising the arms, lifting or manipulating an object, pressing against a surface, holding the arms in the desired position, or other efforts. In an embodiment, the compensation device 102 includes an adjustable cuff 109 to secure the compensation device 102 to the arm of the operator.
[0067] The exoskeleton 100 includes a control system 104 carried by or supported on the frame 106. The control system 104 is arranged to monitor exoskeleton parameters and communicate with at least one of a remote controller 118 and external systems 120 (e.g., for providing data to and receiving data from the exoskeleton). In an embodiment, the remote controller 118 is a wireless device that the operator can use to command different elements of the exoskeleton 100. The remote controller 118 can include a power button to turn on / off the electrical components (e.g., control system 104) of the exoskeleton 100. The remote controller 118 can also include a battery, a joystick, a communication module, a charging port, and status indicators (e.g., LEDs) for the level of assistive torque. The functionality of the control system 104 will be described in greater detail below concerning Figs. 17-19.
[0068] Examples of external systems 120 include networks (e.g., one or more data links, including a database, that enable the wired or wireless transport of electronic data between computer systems or modules or other electronic devices), user panel(s), remote controller(s), and other computing units. For example, the external system 120 can be a smartphone that can be used to send commands to the control system 104 for operating various functions of the exoskeleton 100.
[0069] As noted above, the exoskeleton 100 comprises a frame 106 connected to the compensation device 102 and control system 104. The compensation device 102 is connected to the frame 106 by one or more hinge mechanisms 110, as described in WO 2023 / 180958 Al . The frame 106 is arranged to support the operator's compensation device 102 and control system 104. The frame 106 may comprise a vertical strut extending proximate a user's back and attaching to the user at a lumbar support 107, as described in at least U.S. Patent Publication No. 20230373080 Al, and can also include an adjustment mechanism 108 at a superior part of the frame 106 to accommodate users of varying widths and sizes.
[0070] The compensation device 102 includes an elastic mechanism 112 within a housing 122. The elastic mechanism 112 is configured to generate assistive torque to assist an operator in exerting efforts about a joint axis.
[0071] Fig. 3 is a medial view of a first (i.e., lateral) side of the compensation device 102 of the exoskeleton 100 without a (lateral) portion of a housing 122. The compensation device 102 includes an elastic mechanism 112 within the housing 122. The elastic mechanism 112 is configured to generate assistive torque to assist an operator in exerting efforts on a joint rotation axis Al. The elastic mechanism 112 may be spring-based, including at least one elastic spring element 124 configured to be longitudinally displaced within the housing 122. While the elastic mechanism 112 may be or comprise an extension spring, it will be appreciated if any suitable modality may be used. In an embodiment, the elastic mechanism 112 is of the type described in WO 2023 / 180958 Al.
[0072] In an embodiment, a first bracket assembly 126 of the elastic mechanism 112 is connected to a selector system 114 of the compensation device 102, and a second bracket assembly 128 of the elastic mechanism 112 is connected to an active regulation system 116. The selector system 114 is arranged to adjust the status of the compensation device 102 between unlock, lock, and transparent modes. Advantageously, the selector system 114 could allow different ‘lock’ positions of the compensation device 102 at different angles about thejoint rotation axis Al to create the condition of fully supporting the operator’s arm. As discussed below, the selector system 114 is arranged at the j oint rotation axis A 1 of the housing 122 of compensation device 102 and arm 111 of the exoskeleton 100. The arm 111 is preferably part of a hinge mechanism 110; however, the arm 111 may be part of the frame 106.
[0073] The active regulation system 116 is based on a servomotor 136 and worm gearbox 142 arrangement that can vary the assistive torque level according to different types of inputs (e.g., user status, context-related information, user decision). The active regulation system 116 is arranged to preload a level of assistive torque provided by the elastic mechanism 112. As depicted, the active regulation system 116 includes a servomotor 136 and worm gearbox 142 connected by a rigid coupling 140. These and other various elements of the active regulation system 116 will be described in greater detail below.
[0074] Fig. 4 provides a general overview of the torque profde provided by the elastic (spring- loaded) mechanism 112 of the compensation device 102, wherein the 0° elevation angle (0) corresponds to a neutral shoulder alignment. The torque profde of the compensation device 102 includes a zero-torque phase 130, whereas the compensation device 102 provides neither obtrusive nor assistive action of the exoskeleton 100. As depicted, the zero-torque phase 130 ranges from a first angle Ost, to a minimum elevation angle, up to a transitional angle [3o. In an embodiment, the angle ast is between -40° and 0°. The transitional phase 132 at angle [3o corresponds to the point where the torque profile transitions from the zero-torque phase 130 to an assistance phase 134. In an embodiment, the angle [3o of the transitional phase 132 is between 0° and 30°. The torque profile of the compensation device 102 further includes an assistance phase 134, where assistive torque is provided by the elastic mechanism 112 to the operator of the exoskeleton 100. In an embodiment, the assistance phase 134 provides support from 0° up to 180°.
[0075] Figs. 5A and 5B illustrate cross-sectional views of the active regulation system 116 of the compensation device 102. The active regulation system 116 includes a servomotor 136 fixed to a motor flange 138. In an embodiment, the motor flange 138 is secured to the housing 122 to prevent rotation; however, translation of the motor flange 138 may still be permitted to prevent overloading the servomotor 136 during assembly. A rigid coupling 140 is provided to transmit torque generated by the servomotor 136 to an input shaft 148 of a worm gear 150. The worm gear 150 then transmits the torque to a worm wheel 154 at a worm gearbox 142. In an embodiment, the active regulation system 116 includes a manual input shaft 149 arranged formanually managing the assistive torque level by applying rotation directly (e.g., by hand, key, or another tool) to the manual input shaft 149. Fig. 5B illustrates an internal hardware arrangement 137 about the active regulation system 116. Such internal hardware 137 can include a battery, processor, communication module, and the like.
[0076] Figs. 6A and 6B illustrate perspective views of the active regulation system 116. The worm gearbox 142 is fixed to the housing 122 and configured to be sensorized with an encoder 146. The encoder 146 is configured to measure the angular position of an output shaft 152 of the worm gearbox 142 connected to a cam 158. In particular, the encoder 146 is configured to measure the position of the cam 158 about a regulation axis A2 for deriving the level of assistive torque. The output shaft 152 of the worm gearbox 142 is connected to the cam 158. The cam 158 is arranged to modify the distance, via operation of the worm gearbox 142, between bracket assemblies 126, 128 of the elastic mechanism 112, like that described in U.S. Patent No. 11,801,596 B2, which is incorporated by reference. A linkage assembly 156 of the second bracket assembly 128 connects the elastic mechanism 112 to the cam 158. The cam 158 is supported by a bearing element 160 of the worm gearbox 142 and another bearing element 162 of a bearing support 164. The cam 158 is secured in place by one or more fasteners 161, such as a screw, bolt, pin, etc.
[0077] Fig. 7 is a partial side view of various modes of a selector system 114. As noted above, the selector system 114 allows the compensation device 102 to be switched among modes: unlock 167, lock 169, and transparent 171 modes. While in the unlock mode 167, which includes the operation of the exoskeleton 100 with assistance, the compensation device 102 can be moved up and down (i.e., flexion and extension) while generating the assistive torque profile. While in the lock mode 169, the exoskeleton 100 is blocked in a determinate position. Such can be advantageous for a safe stockage or full support at a predefined angle. The principle can be used to create one or more positions in which the compensation device 102 can be blocked to create a sort of support where the operator can rest his or her arm. While in transparent mode, wherein the exoskeleton 100 is without assistance, the compensation device 102 can move up and down.
[0078] Fig. 8 provides an exploded view of the selector system 114, and Fig. 9 provides a cross-sectional view of the selector system 114. The arm 111 is fixed on one side to the proximal part of the exoskeleton 100 and on the other side to a spacer cage 168 and spring- loaded mechanism shaft 182. The spacer cage 168 has one or more machined areas or gaps 170that accommodate a set of rollers 176. The spacer cage 168 helps to keep the position of each roller 176 while permitting movement to slide radially from the joint rotation axis Al. In an embodiment, the spacer cage 168 is directly machined from the arm 111 as a single (i.e., monolithic) piece.
[0079] The selector switch 166 is connected via a form-fit coupling to a prismatic coupler shaft 172 and is axially fixed by a screw 165 along the joint rotation axis Al. The selector switch 166 is arranged to rotate in accordance with the arm 111 and spacer cage 168. The prismatic coupler shaft 172 is coupled to a selector shaft 178 via a prismatic joint. The selector shaft 178 is arranged to rotate under the action of the selector switch 166 while being free to slide on the joint rotation axis Al. In particular, the rotation of the selector switch 166 can cause one or more rollers 176 to engage with a socket rim 173 to arrest movement of the compensation device 102 about the joint rotation axis Al .
[0080] The compensation device 102 can be switched to a transparent mode 171 by the conditions and method specified in WO 2023 / 180958 Al. An inhibitor pin 179 is integrated with the selector shaft 178. When the selector switch 166 is rotated to be set to transparent mode 171, the selector shaft 178 rotates while sliding over a set of balls 188 (e.g., three) kept in position by a ball cage 190. The ball cage 190 may be contained by a bearing member 186 positioned between the socket rim 173 and the spring -loaded mechanism shaft 182.
[0081] Fig. 10 illustrates a perspective view of a selector shaft 178 for the selector system 114. The selector shaft 178 includes a radial cam surface 181 with one or more projections 187 arranged to push the rollers 176 outside the outer diameter of the spacer cage 168 against the socket rim 173. A vertical cam surface 183 allows the selector shaft 178 to translate along the joint rotation axis Al . When rotation of the selector shaft 178 about the joint rotation axis Al causes the vertical cam depressions 185 to encounterthe balls 188, the selector shaft 178 axially slides, being pushed downward (i.e., toward the housing) by a selector spring 174. When inserted, the inhibitor pin 179 disables the torque mechanism. In this condition, the inhibitor pin 179 is inserted into a spring pin 180. When the inhibitor pin 179 is engaged with the spring pin 180, the spring of the passive mechanism can’t release its energy because the “lever” is fixed. Thus, the box can move, but without any torque assistance.
[0082] Figs. 11A and 1 IB are partial side views of the selector system 114 in disengaged and engaged positions of the rollers 176 and socket rim 173. In Fig. 11A, the rollers 176 are not pushed against the socket rim 173 and instead remain within the outer diameter of the spacercage 168. In this state, the compensation device 102 can rotate about the joint rotation axis Al while the elastic mechanism 112 mechanism generates assistive torque in an assistance phase 134 of the torque profile. In an embodiment, wherein the socket rim 173 includes multiple sets of sockets 175, 177 arranged to lock the compensation device 102 in multiple positions about the joint rotation axis Al with full support of an operator’s arm. In Fig. 1 IB, the radial cam surface 181 of the selector shaft 178 pushes out the set of rollers 176 (i.e., away from the joint rotation axis) to engage the socket rim 173. Thus, if an operator tries to move an arm, the rollers 176 collide with the spacer cage 168, inhibiting movement. Such is observed in Fig. 12, wherein the attempted external force Fl to rotate the compensation device 102 about the joint rotation axis Al is prevented by the internal forces F2 acting between the spacer cage 168, socket rim 173, and the rollers 176.
[0083] Figs. 13A and 13B illustrate partial side views of an alternative embodiment of the selector system 114 wherein only one set of sockets 175 is arranged in a specific position to create a condition of full support of the user’s arm weight (e.g., 90°). Additionally, or alternatively, the arrangement in Figs. 13A and 13B can create a condition to ensure a secure storage position (e.g., -30°). One skilled in the art will recognize that the number of rollers can be greater or lesser than what is depicted, the diameter can be bigger or smaller, and the number of sockets along the socket rim can be adjusted. Customization of the specific components of the selector system 114 depends on several reasons, such as maximum external torque and / or the number of fixed positions needed. In an embodiment, each roller 176 and socket 175 of the set can have different diameters or heights to ensure the engagement occurs in a univocal position.
[0084] Fig. 14 provides a cross-sectional view of the selector system 114 in an engaged configuration. As observed, the inhibitor pin 179 is forced into the spring pin 180, and the one or more balls 188 rest within depressions 185 formed along the vertical cam surface 183. Fig. 15 illustrates a counter cam profile for a selector system 114. In an embodiment, a counter cam profile 189 is machined in the spring -loaded mechanism shaft 182; rather than requiring the balls 188 and ball cage 190 for interfacing with the vertical cam surface 183. The counter cam profile 189 includes a pocket 191 and protrusions 193 to slidingly engage with the depressions 185 of the vertical cam surface 183.
[0085] Figs. 16A and 16B are cross-sectional views of the compensation device 102 at approximately 90° elevation in disengaged and engaged configurations of the selector system114. In Fig. 16A, the inhibitor pin 179 is disengaged from the spring pin 180, and the linkage assembly 184 of the first bracket assembly 126 is free to move with the elastic mechanism 112, generating the assistive torque profile. In contrast, Fig. 16B shows the inhibitor pin 179 engages the spring pin 180 with the linkage assembly 184 and the compensation device is in a transparent mode 171.
[0086] Fig. 17 is a schematic drawing of a control system 200, which can be applied to the control system 104 for an exoskeleton system. In an embodiment, the control system 200 includes a microcontroller 202 configured to control algorithms and drive the other systems. Such systems include a user interface 204, a sensory system 206, one or more drivers 208, one or more actuators 210, and a communication module 212.
[0087] The user interface 204 may include buttons that allow powering on / off the exoskeleton 100, selecting working modalities (e.g., assistance levels), and displaying the relevant status of the device via LED indicators. The sensory system 206 is configured to read relevant information from the compensation device 102 (e.g., a joint encoder 144 at the joint rotation axis Al, cam encoder 146 at the active regulation system 116, and mode sensor 145 at the selector system 114).
[0088] The drivers 208 are responsible for powering actuation commands to actuators 210 (e.g., servomotors 136), and the actuators 210 are responsible for driving the (passive) elastic mechanism(s) 112 to change the level of assistance. Finally, a communication module 212 (e.g., Wi-Fi unit) allows networking with external systems 214, such as a user panel or remote controller, to indicate status, programming, and assistance selection. The external system 214 can also send commands to the control system 200.
[0089] Fig. 18 is a flowchart of actuation control by the control system 200. A control loop for the actuators 210 (e.g., separately for right and left compensation devices) can be an open loop current control. For example, once a new level LevelDesis requested, the microcontroller 202 compares the level corresponding to the actual cam position Level(9camj. The comparison result determines the pulse width modulation (PWM) duty cycle PWM. The PWM duty cycle is a function of the actual cam position 9Cam, namely PWM eCam) ■ nd P(9camjisselected to generate a current i from the driver 208 to the actuator 210 that is capable of rotating the cam 201 with a velocity 9Camto keep 9Camconstant independently on the cam position in which the change of assistance occurs. In an embodiment, PWM(9cawaiqdidentifiedthrough the modeling of the response of the same system to a closed-loop velocity control of the cam rotation 9Cam
[0090] Fig. 19 illustrates a flowchart for computing instantly delivered torque. As depicted, the joint encoder 144 reads the joint angle (0j ), and the cam encoder 146 reads the current level of assistance (Level) provided by the elastic mechanism 112. A mode sensor 145 is configured to detect which mode is selected (e.g., assistive mode vs. transparent mode) by assessing the engagement positions of the spring pin 180. Instantly delivered torque is computed as the product between 0j and the resulting stiffness of the spring-loaded mechanism as a function K(Levei,Mode, 0j ). TONSET and TOFFSET are respectively the instants in which the angle 0j is greater / lower than a certain threshold 0Th. Adsorbed torque for each shoulder flexion xAdsis computed (e.g., for each arm) as the integral from TONSET to TOFFSET of the instantly delivered torque
[0091] The embodiments of this disclosure overcome the disadvantages observed in the prior art and provide exoskeleton solutions arranged to vary the assistance level according to different types of inputs (e.g., user status, context-related information, and user decision). The compensation device can be switched between different conditions (e.g., locked, unlocked, and transparent). Different locked positions of the compensation device can be produced to create conditions of fully fixed support, and the control of switching between the different conditions can be customized.
[0092] It is understood that not all objects or advantages may be achieved under any embodiment of the disclosure. Those skilled in the art will recognize that upper limb exoskeletons may be embodied or carried out to achieve or optimize one advantage or group of advantages as taught herein without achieving other objects or advantages as taught or suggested herein.
[0093] The skilled artisan will recognize the interchangeability of various disclosed features. Besides the variations described herein, other known equivalents for each feature can be mixed and matched by one of ordinary skill in this art to build and use exoskeleton and assistive devices under principles of the present disclosure. The skilled artisan will understand that the features described herein may be adapted to other methods and types of exoskeleton device s / applications.
[0094] It is intended that the present disclosure should not be limited by the disclosed embodiments described above and may be extended to other applications that may employ the features described herein.
Claims
CLAIMS1. An upper-limb exoskeleton (100) comprising: a compensation device (102) including an elastic mechanism (112) configured to generate assistive torque about a joint rotation axis (Al) to assist an operator in exerting efforts; and a control system (104) operatively connected to the compensation device (102) and configured to vary a level of the assistive torque by actuating an active regulation system (116) within the compensation device (102); wherein the active regulation system (116) comprises a servomotor (136), a worm gearbox (142), and a cam (158) arranged to modify a distance between a first bracket assembly (126) and a second bracket assembly (128) of the elastic mechanism (112) to preload the assistive torque; and wherein the control system (104) is further configured to control the assistive torque level according to user input or context-related information to selectively operate the exoskeleton (100) in an unlock mode (167), a lock mode (169), or a transparent mode (171).
2. The upper-limb exoskeleton (100) of claim 1, wherein the compensation device (102) includes a housing (122) containing the elastic mechanism (112), the elastic mechanism (112) being spring-based and configured to provide a torque profile comprising a zero-torque phase, a transitional phase, and an assistance phase.
3. The upper-limb exoskeleton (100) of claim 2, wherein the active regulation system (116) further comprises a cam encoder (146) configured to measure a position of the cam (158) about a regulation axis (A2) for determining the level of assistive torque.
4. The upper-limb exoskeleton (100) of claim 2, wherein the compensation device (102) further comprises a selector system (114) arranged to adjust a status of the compensation device (102) between the unlock mode (167), the lock mode (169), and the transparent mode (171).
5. The upper-limb exoskeleton (100) of claim 4, wherein the selector system (114) comprises a selector shaft (178) arranged to rotate about the j oint rotation axis (A 1 ) by a selector switch (166) and to translate along the joint rotation axis (Al) to adjust the status between the unlock, lock, and transparent modes.
6. The upper-limb exoskeleton (100) of claim 5, wherein the selector system (114) further comprises a spacer cage (168) containing one or more rollers (176) arranged to be displaced by a radial cam surface ( 181 ) of the selector shaft (178) away from the j oint rotation axis (Al) against a socket rim (173) of the housing (122).
7. The upper-limb exoskeleton (100) of claim 6, wherein the socket rim (173) comprises multiple sockets (175, 177) arranged to lock the compensation device (102) in multiple positions about the joint rotation axis (Al) to provide full support of an operator’s arm.
8. The upper-limb exoskeleton (100) of claim 5, wherein the selector system (114) further comprises a ball cage (190) containing one or more balls (188) arranged to contact a vertical cam surface (183) of the selector shaft (178), the vertical cam surface (183) including one or more depressions (185) configured to receive the one or more balls (188) when the selector system (114) is in the transparent mode (171).
9. The upper-limb exoskeleton (100) of claim 8, wherein the transparent mode (171) includes an inhibitor pin (179) of the selector shaft (178) being inserted into a spring pin (180) of the first bracket assembly (126) to disable the assistive torque.
10. The upper-limb exoskeleton (100) of claim 8, wherein the control system (104) is wirelessly connected to a remote controller (118) configured to operate at least one of the selector system (114) and the active regulation system (116).
11. The upper-limb exoskeleton (100) of claim 10, wherein the control system (104) is configured to compute the assistive torque level based on at least one of user status data, contextual data, or user-selected assistance parameters received via the remote controller (118).
12. The upper-limb exoskeleton (100) of claim 1, wherein the control system (104) comprises a microcontroller (202) configured to control actuation of the compensation device (102) using an open-loop current control by comparing, after receiving a request for a new level of assistive torque, the requested level to an actual position of the cam (158, 201) to determine a pulse-width modulation duty cycle as a function of the actual cam position; and generating a current (i) to an actuator (210) arranged to rotate the cam (158, 201) with a constant velocity independent of a position at which a change of assistive torque occurs.
13. The upper-limb exoskeleton (100) of claim 12, wherein the microcontroller (202) is further configured to compute instantly delivered torque as the product between an angle (0j) about the joint rotation axis (Al) and a resulting stiffness of the elastic mechanism (112) using a function of a current level of assistive torque, a status of the compensation device (102), and the angle (0j).
14. The upper-limb exoskeleton (100) of claim 13, wherein adsorbed torque for each joint flexion is computed as an integral from onset (TONSET) to offset (TOFFSET) of the instantly delivered torque, onset and offset being instants in which the angle (0j) about the joint rotation axis (Al) is greater and lower, respectively, than a predetermined threshold angle (0Th).
15. The upper-limb exoskeleton (100) of claim 1, wherein the compensation device (102) is carried by a frame (106) adapted to be worn on a back of the operator, the frame (106) including a lumbar support (107) and an adjustable mechanism (108) for accommodating users of varying sizes.
16. A method for operating an upper-limb exoskeleton (100) comprising a compensation device (102) and a control system (104), the method comprising: receiving, by the control system (104), a request for a new level of assistive torque; comparing the requested level of assistive torque to an actual position of a cam (158) of an active regulation system (116); and driving an actuator (210) to rotate the cam (158) with a constant velocity independent of a position at which a change of the assistive torque occurs.
17. The method of claim 16, further comprising determining, by the control system (104), a pulse-width modulation duty cycle as a function of the actual cam position, wherein the duty cycle is used to generate a current (i) to the actuator (210) to rotate the cam (158).
18. The method of claim 16, further comprising computing, by a microcontroller (202), an instantly delivered torque as the product between an angle (0j) about a joint rotation axis (Al) and a stiffness of an elastic mechanism (112) using a function of a current level of assistive torque, a status of the compensation device (102), and the angle (0j).
19. The method of claim 18, further comprising switching a selector system (114) between an unlock mode (167), a lock mode (169), and a transparent mode (171) by rotating and translating a selector shaft (178) about and along the joint rotation axis (Al), the transparent mode (171) including inserting an inhibitor pin (179) into a spring pin (180) to disable the assistive torque.
20. A system comprising: an upper-limb exoskeleton (100) according to claim 1, and a computing unit (202) configured to execute the method of claim 16; wherein the computing unit (202) is operatively connected to the control system (104) to receive sensor data, process control algorithms, and transmit control signals to actuators (210) of the compensation device (102) to regulate assistive torque, switching modes, and torque computation in real time.