Passive lumbar exoskeleton
The passive exoskeleton with an assistive torque assembly addresses discomfort and adaptability issues by providing customizable torque support, enhancing operator comfort and safety in industrial tasks.
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 IB2025062056_04062026_PF_FP_ABST
Abstract
Description
PASSIVE LUMBAR EXOSKELETON
[0001] CROSS-REFERENCE TO RELATED PATENTS AND APPLICATIONS
[0002] This application incorporates by reference U.S. Patent Publication No. 2024 / 0308060 Al, published on September 19, 2024, and International Application No. PCT / IB2023 / 062726, published on June 20, 2024, as WO 2024 / 127327 AL
[0003] FIELD OF THE DISCLOSURE
[0004] The disclosure relates to an exoskeleton, particularly a passive lumbar exoskeleton, and supporting assistive devices adapted to augment an operator's performance, mitigate repetitive strain injuries, and assist in exerting forces.
[0005] BACKGROUND
[0006] Workers in numerous settings are vulnerable to various occupational diseases, including overuse injuries, fatigue, and workplace accidents. A typical industrial disease includes overuse and strain resulting from biomechanical lumbar overload. Biomechanical lumbar overload can result from, for example, an operator lifting heavy-weighted items from the ground or repeatedly lifting a moderate weight from the ground, mainly if the lifting is done with poor posture.
[0007] Biomechanical lumbar overload can also result from an operator bending or repeatedly stooping during work activities, such as a worker in an automobile manufacturing facility bending or stopping to work on the part of a vehicle that is low to or only accessible from the ground. Biomechanical lumbar overload may result in numerous and costly problems, including occupational diseases ranging from pain, muscle weakness, swelling, numbness, and restricted mobility of the back to debilitating pain and life-threatening accidents.
[0008] Low back pain is the primary cause of disability in individuals under the age of 50. It is most frequently associated with occupations requiring physical exertion, resulting in acute injuries and cumulative stresses to the spinal anatomy. Other occupational diseases include degenerative cervical spine disease, discogenic low back pain, and spinal stenosis, to name a few, all of which can be exacerbated by poor posture and repetitive and arduous physical tasks.
[0009] Wearable industrial exoskeleton technologies can improve endurance and safety in industrial settings, increase industrial productivity, and prevent common workplace injuries by minimizing muscle and tendon overuse and preventing excessive stress on the spine and lowerback. Exoskeletons can support and augment an operator during strenuous activities, including lifting, stooping, bending, squatting, and overhead work, to reduce employee fatigue and workplace injuries and improve precision and the speed of work tasks. Exoskeletons may be additionally valuable in repetitive and awkward activities. An exoskeleton allows operators to lift heavy objects safely and effortlessly with less effort, increasing productivity and accuracy by reducing muscle fatigue. Through an exoskeleton, older workers with valuable experience and intuition may be able to work longer than they otherwise could in physically demanding or challenging jobs.
[0010] An exoskeleton may be arranged to transfer loads through the exoskeleton to the ground in standing or kneeling positions, allowing operators to use heavy tools as if they were weightless. The exoskeleton can be configured to move naturally with the body and adapt to different body types and heights. The exoskeleton can replicate the body's biomechanical movement, while a corresponding interface can enwrap or engage with the operator's body.
[0011] An exemplary exoskeleton enhances performance in the lower body, including the trunk and thighs. It reduces forces on the lower back (e.g., torque on the spine and lower back produced when lifting or squatting). It enables the operator to perform repeated lifts over an extended period with less effort. The exoskeleton may help the operator lift objects and reduce physical risks and discomfort from tasks carried out by bending at the knees, hips, or waist.
[0012] Active and passive exoskeletons have been found to benefit the lower body, trunk, and upper body regions. They have also been reported to reduce muscle activity. Exoskeletons can potentially reduce the underlying factors associated with work-related musculoskeletal injury.
[0013] However, while certain exoskeletons are available, several technical issues hinder the practical and widespread use, adoption, and compliance of exoskeletons in the industry. Specific problems include discomfort for both passive and active exoskeletons, the device's weight, poor alignment with human anatomy and kinematics, and inability to detect the human intention to enable smooth movement for active exoskeletons and the case of use to ensure consistent and compliant service.
[0014] Another issue is ensuring that an exoskeleton's assistance is commensurate with the operator's particular needs and activities. Existing systems may provide static or dynamic assistive forces but require complex control and adjustment systems. Adapting exoskeletons to different operators in subsequent shifts and other tasks is costly and impractical. Still, existingexoskeletons must be more adaptable to the operators' specific dimensions, strengths, and tasks, leading to poor compliance and poor results across different operators.
[0015] Existing exoskeleton devices may need to be better adapted to allow an operator to perform unrelated tasks and be doffed if such tasks are to be comfortably and effectively executed. Accordingly, convenient and temporarily deactivated exoskeletons without removing the device are needed.
[0016] Safety concerns further limit the widespread adoption and use of exoskeletons. As an exoskeleton can support the extension and flexion of an operator's joints, an operator can be injured through over-extension or over-flexion of joints due to the assistive forces provided by these devices. Similar concerns exist regarding damage to the exoskeletons themselves or nonoperators, as tension stored in exoskeletons may be released suddenly when not in use, causing damage to the exoskeletons and their surroundings to be expensive to mitigate or repair. A need exists for safer and more straightforward to operate exoskeletons.
[0017] Another problem is that the exoskeleton hinders an operator's normal activities. For example, it may make tasks as straightforward as walking difficult or cumbersome by engaging or providing torque even when not necessary or desired. Passive exoskeletons are poorly adapted to the specific biomechanical requirements of different activities, such as bending vs. stooping. They cannot provide convenient variability in the amount of torque concerning the joint's angular displacement.
[0018] Given the preceding discussion, an exoskeleton, particularly a passive exoskeleton, is needed to facilitate compliant and consistent use by an operator while providing necessary assistive torque in various desired motions and angles and according to a desired torque level.
[0019] SUMMARY
[0020] An assistive torque assembly is provided for a compensation device of an exoskeleton. The compensation device includes a thigh link rotatably connected to the assistive torque assembly. The assistive torque assembly is configured to produce an assistive torque about at least one joint of an operator of the exoskeleton. The assistive torque assembly includes at least one elastic mechanism, and a torque output mechanism configured to displace the at least one elastic mechanism to generate and transfer torque to the operator.
[0021] The torque output mechanism includes an angular offset to adjust the assistive torque's engagement. The mechanism may include a torque profile modifier to adjust the elasticmechanism's deflection rate. The torque output mechanism can include the angular offset mechanism and the torque profile modifier.
[0022] The angular offset mechanism includes a selection shaft arranged to rotate about a first axis of the at least one joint of the operator and to displace a first set of pawls to a first angular engagement position. The angular offset mechanism can have a layered configuration by including a second set of pawls for rotatably connecting the engagement cam and the thigh link at a second angular engagement position for offsetting the angular position when the torque output mechanism about the joint of the user provides assistive torque. The angular offset mechanism acts as an on / off switch to select between disengaged and various engaged assistance levels. The angular offset mechanism further customizes or offsets the angle at which assistive torque is provided.
[0023] The layered sets of pawls are concentric about the first axis. The selection shaft comprises teeth configured to engage with the pawls, and the selection shaft may have varying levels of teeth to engage with the different sets of pawls. In an embodiment, the first set of pawls has a free range of motion within the engagement cam when the first set of pawls is arranged in the first angular engagement position. The second set of pawls can have a reduced range of motion, no range of motion, or a negative free range of motion when the first set of pawls is arranged in the first angular engagement position. By “negative free range of motion,” it is understood that the angular offset mechanism can set the limit angle (i.e., the transition between free movement and active exoskeleton mode) at a negative hip angle (e.g., with the leg moved backward).
[0024] The torque output mechanism can include at least one auxiliary cam with at least one auxiliary displacement profile to adjust the deflection rate of the elastic mechanism using the torque profile modifier. The engagement cam has a displacement profile that displaces the elastic mechanism when it is rotated about the first axis. The torque profile modifier can include a shift lever that adjusts the deflection rate of the elastic mechanism between the displacement profile of the engagement cam and the auxiliary displacement profile of at least one auxiliary cam.
[0025] Displacement of the shift lever about the first axis can position the engagement cam to move together with the at least one auxiliary cam and to allow deflection of the elastic mechanism by the auxiliary displacement profile. The shift lever can further be displaced to position the engagement cam to move independently from the at least one auxiliary cam and to allow deflection of the elastic mechanism by the displacement profile.
[0026] The assistive torque assembly further comprises an assistive regulation device configured to preload a level of assistive torque provided by at least one elastic mechanism. In particular, the device includes a preloading cam arranged to rotate by a regulator shaft to move the second end of the elastic mechanism away from the torque output mechanism. Advantageously, the rotation of the preloading cam can exceed 360° to reduce the required torque to modify the level of assistance.
[0027] The assistive torque assembly can further comprise an electronic board configured to compute instantly delivered torque as a product of the angular displacement of the assistive torque assembly about at least one joint and the stiffness of the elastic mechanism as a function of the current level of the assistive torque, a mode of the torque profile modifier, the angular engagement position of the angular offset mechanism, and the angular displacement of the assistive torque assembly about at least one joint.
[0028] These and other features, aspects, and advantages of the present disclosure will be better understood in the following description, appended claims, and accompanying drawings.
[0029] BRIEF DESCRIPTION OF THE DRAWINGS
[0030] The figures are not necessarily drawn to scale but to provide a better understanding of the components thereof. They are not intended to be limiting in 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.
[0031] Fig. 1A illustrates a rear or posterior perspective view of an embodiment of an exoskeleton.
[0032] Fig. IB illustrates a front or anterior perspective view of an embodiment of the exoskeleton.
[0033] Fig. 2 illustrates a perspective view of an embodiment of a compensation device.
[0034] Fig. 3 illustrates a sectional view of an embodiment of an assistive torque assembly for the compensation device.
[0035] Fig. 4 illustrates a sectional view of a torque output mechanism for the assistive torque assembly.
[0036] Fig. 5 illustrates a sectional view of an angular offset mechanism.
[0037] Fig. 6 illustrates perspective views of pawl component embodiments for the angular offset mechanism.
[0038] Fig. 7 illustrates a perspective view of the angular offset mechanism and engagement cam.
[0039] Fig. 8 illustrates a perspective view of a layered, angular offset mechanism.
[0040] Figs. 9A and 9B illustrate the layered angular offset mechanism’s perspective and partial cross-sectional views.
[0041] Fig. 10 illustrates a chart showing disengaged and engaged positions of the layered, angular offset mechanism.
[0042] Fig. 11 illustrates a plot of translating assistance level profiles.
[0043] Fig. 12 illustrates partial side views of an embodiment of a compensation device in various operation stages corresponding to an operator's squatting and stooping motions.
[0044] Fig. 13 illustrates a plot of exemplary output torques of an embodiment of a compensation device having an angular offset mechanism according to the joint angle of an operator.
[0045] Figs. 14A-14B illustrate side views of an engagement cam.
[0046] Fig. 15A illustrates a partial cross-sectional view of a torque profile modifier provided with the torque output mechanism.
[0047] Figs. 15B-15C illustrate diagrams of force distribution for the torque profile modifier in Fig. 15A.
[0048] Fig. 16 illustrates cross-sectional views of an embodiment of a compensation device between modes of torque profile operation.
[0049] Fig. 17 illustrates cross-sectional views of an embodiment of a compensation device between modes of torque profile operation corresponding to angular displacement.
[0050] Figs. 18A-18C illustrate perspective, side, and cross-sectional views of an embodiment of a torque profile modifier with separated engagement and auxiliary cams.
[0051] Figs. 19A-19C illustrate perspective, side, and cross-sectional views of the embodiment of the torque profile modifier in Figs. 18A-18C with interlocked engagement and auxiliary cams.
[0052] Fig. 20 illustrates a cross-sectional view of an embodiment of an assistive torque assembly.
[0053] Fig. 21 illustrates a schematic view of an embodiment of an assistance regulation device at various exemplary operational configurations.
[0054] Fig. 22 illustrates an upper perspective view of the assistive torque assembly in Fig. 20.
[0055] Fig. 23 illustrates a cross-sectional view of the assistive torque assembly in Fig. 22.
[0056] Fig. 24 illustrates a cross-sectional view of an assistive torque assembly with various electronic components that determine a mode of torque profile operation.
[0057] Fig. 25 illustrates a schematic sensor diagram for an assistive torque assembly.
[0058] DEFINITIONS
[0059] As used, the terms "rigid," “flexible,” “compliant,” and “resilient” may distinguish characteristics of portions of certain features of the actuation system. The term “rigid” should denote that an element of the actuation system, such as a frame, is generally devoid of flexibility. Within the context of features that are “rigid,” 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 non-retained shapes or that the features do not retain a general shape but continuously deform when force is applied. The term “resilient” may qualify as flexible features that return to an initial general shape without permanent deformation. As for the term “semi-rigid,” 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.
[0060] The term "approximately" means a value within a statistically significant range of values or values, such as the stated length, distance, weight, height, angle, or force.
[0061] The term "elastic" means recovering in size and shape after deformation.
[0062] The term “elastic mechanism” refers to a passive device that does not draw energy from an external power supply. As described herein for exemplary purposes, the elastic mechanism is an actuation mechanism having an elastic or spring-like member.
[0063] The term “exoskeleton” refers to an assistive device that can be worn or attached to a user and contributes to realizing a support, hold, or force transmission function concerning one or more portions of the user.
[0064] The term “free range of motion” in the context of the angular offset mechanism describes a range of the torque generator device that provides neither obtrusive nor assistive action of an exoskeleton. The free range of motion is a zero-torque range where zero newtonmeters (N m), or substantially zero N m, of torque, is applied within a predetermined angular joint flexion and extension range. The only torque perceived by the user while assistive torque assembly operates in the zero-torque range may be friction torques, or the torque generated by the weight of the torque generator device.
[0065] The term "operator" or “user” refers to someone using the exoskeleton. The user may be a patient or an operator.
[0066] The terms “substantial” or “substantially” mean that the recited characteristic, parameter, or value need not be achieved exactly but that deviations or variations, including, for example, tolerances, measurement error, measurement accuracy limitations, and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide. The terms “substantial” or “substantially” mean ±10% in some embodiments, ±5% in some embodiments, and ±1% in some embodiments.
[0067] DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS
[0068] Figs. 1A and IB illustrate an exoskeleton 10 of the type disclosed in WO 2024 / 127327 Al, incorporated by reference. The exoskeleton 10 comprises one or more compensation devices 12 arranged to provide and transfer assistive forces to a user. The exoskeleton 10 comprises a physical Human-Robot interface (pHRI) 14 configured to be worn by the user and to ensure safe and effective force transfer between the user and the compensation device 12. In an embodiment, the pHRI 14 comprises an upper-body brace 16, a lumbar belt system 18, and a thigh link assembly 20 as connection points to the user.
[0069] Fig. 2 illustrates a perspective view of a compensation device 100 that may be implemented with an exoskeleton 10. The compensation device 100 is configured to compensate for resistive moments acting on the hip joint during an effort exerted by or movement of the user. In addition, the compensation device 100 is configured to provide assistive forces to supplement the operator's actions, such as standing up from a bending or stooping position.
[0070] The compensation device 100 comprises an assistive torque assembly 102 configured to produce an assistive torque about the first axis II of rotation due to hip joint movement. The first axis of rotation II is configured to align or substantially align with the hip joint of theoperator. The compensation device 100 also comprises a thigh link 104 connected to the assistive torque assembly 102, the thigh link 104 being rotatable about the first axis of rotation Il and defining or cooperating with a thigh cuff 110 engageable by a thigh of the operator to produce resistive moments about the first axis of rotation II.
[0071] In an embodiment, the thigh cuff extends primarily about the front side of the operator's thigh. The thigh cuff may cooperate with one or more straps or another link (not shown) that connect to the thigh link 104 and extend about the back side of the operator's thigh to substantially circumscribe the operator's thigh and provide assistive forces. According to the illustrated embodiment, the thigh link 104 may be configured to facilitate abduction / adduction motions, e.g., using a connection element about an axis AAb / Ad, to allow the exoskeleton 10 to closely fit and conform to an operator and the operator's movements.
[0072] The compensation device 100 includes a torque output mechanism 106 configured to disengage and engage the assistive torque assembly 102 to turn on and off the provision of assistive torque in response to resistive moments. The compensation device 100 includes an assistive regulation device 108 for adjusting tension in an elastic mechanism 112. That is, the assistive regulation device 108 determines a base level of loading in the spring of the elastic mechanism 112 and can proportionally adjust the base level concerning the joint angle between the thigh and the trunk of the operator. As discussed in greater detail below, the loading and assistive torque the compensation device 100 provides during engagement increases by utilizing the assistive regulation device 108 to increase the base level assistive torque corresponding to a standing position.
[0073] Fig. 3 illustrates an embodiment of an assistive torque assembly 102 for the compensation device 100. The assistive torque assembly 102 includes an elastic mechanism 112 configured to generate a torque proportional to angular displacement about a joint of a user. The elastic mechanism 112 and various other assistive torque components are contained within a housing 116 of the assistive torque assembly 102.
[0074] The elastic mechanism 112 may be spring-based, including at least one elastic spring element configured to be displaced in anterior A and posterior P directions. While the elastic mechanism 112 may be or comprise an extension spring, it will be appreciated if any suitable modality may be used. For example, the elastic mechanism 112 may comprise a compression spring, a torsion spring, an elastic wire, combinations thereof, or any other suitable component.The elastic mechanism 112 may be configured to cooperate with one or more of the components mentioned above to provide an assistive torque.
[0075] The assistive torque assembly 102 includes atorque output mechanism 106 coaxial with the first axis II and in contact with a first end 118 of the elastic mechanism 112. As described in greater detail, the connection between the first end 118 and the torque output mechanism 106 may be provided via a cam profile, bearing, or the like. The torque output mechanism 106 comprises an angular offset mechanism 114 arranged to adjust the angular engagement of the assistive torque between the torque output mechanism 106 and at least one elastic mechanism 112. The angular offset mechanism 114 permits selection between two or more engagement positions of the assistance torque, thereby providing options for the angular offset of the assistance profile against the first end 118 of the elastic mechanism 112. The second end 120 of the elastic mechanism 112 may be rotatably fixed to the housing 116 or connected to an assistive regulation device 108.
[0076] The assistive torque assembly 102 includes the torque output mechanism 106, and a torque profile modifier 115 arranged to adjust the deflection rate of the elastic mechanism 112 by the torque output mechanism 106. The torque profile modifier 115 may be operable by a shift lever 122 configured to rotate about the first axis II .
[0077] Fig. 4 illustrates a sectional view of the angular offset mechanism 114 provided with the torque output mechanism 106. The angular offset mechanism 114 comprises a selection shaft 124 arranged to rotate about the first axis II of the at least one joint of the operator. The selection shaft 124 includes a coaxial pin 134 arranged within the selection shaft 124 and along the first axis II . The angular offset mechanism 114 is configured to displace a first set of pawls 128, contained by a rotatable member 132 coaxial with the first axis II, between engagement positions for rotatably connecting an engagement cam 126 and the thigh link 104.
[0078] The set of pawls 128 is configured to rotate within a coaxial opening 146 of the engagement cam 126. The selection shaft 124 comprises a set of teeth 138 arranged to displace the set of pawls 128 beyond a circumferential periphery 148 of the rotatable member 132 into a groove 144 defined by the engagement cam 126. A free range of motion is provided for the rotatable member about the first axis II defined by contact between the unrestrained movement by each pawl 128 between the teeth 138 of the selection shaft 124 and the contact point 141 against the engagement cam 126. As described herein, references to a single pawl or tooth can likewise apply to a plurality of pawls or teeth.
[0079] Each pawl 128 is displaceable about a pivot pin 136 to become aligned and offset with the circumferential periphery 148 of the rotatable member 132. Each pivot pin 136 is contained within a cavity 152 formed by the rotatable member 132. The pawl 128 may define a recess 142 configured to interface with the teeth 138 of the selection shaft 124. In an engaged configuration, the pawl 128, being rotatable about the pivot pin 136, includes a ridge 150 surface that extends beyond the circumferential periphery 148 of the rotatable member 132. In a disengaged configuration, an edge 154 of the pawl 128 is aligned with the circumferential periphery 148 of the rotatable member 132. In an embodiment, the edge 154 may not be circumferentially aligned with the circumferential periphery 148 and may fall within the circumferential periphery 148, i.e., extend radially toward the first axis II.
[0080] Fig. 5 illustrates an alternative embodiment of the angular offset mechanism 114. As depicted, rather than an engagement cam 126 assembly, the angular offset mechanism 114 includes a mechanism frame 156 that may be fixed to the first end 118 of the elastic mechanism 112. Like the engagement cam 126, the mechanism frame 156 features grooves 144 for engaging with the pawls 128. Additionally, the rotatable member 132 may include at least one pin 137 that may extend through the rotatable member 132 to connect with another rotatable member or thigh link 104 member. The angular offset mechanism can include a bearing 158 arranged between the mechanism frame 156 and the rotatable member 132 to allow the rotatable member 132 to rotate about the first axis II concerning the mechanism frame 156.
[0081] Fig. 6 illustrates perspective views of pawls 128, 131 that may be used with the angular offset mechanism 114. The first pawl 128 includes a recess 142 to engage with the teeth 138 ofthe selection shaft 124. The pawl includes a recess 162 to receive a pivot pin 136 that defines a second axis 12, about which the pawl 128 is displaceable. The second axis 12 is substantially parallel to the first axis II. The pawl 128 includes an edge 154 that substantially aligns with the circumferential periphery 148 of the rotatable member 132 to allow disengaged rotation of the angular offset mechanism 114 about the first axis II. The pawl 128 includes a ridge 150 arranged to extend beyond a circumferential periphery 148 of the rotatable member 132 and to move within a recess 142, wherein the boundaries of the ridge 150 displacement are determined between tooth 138 and contact point 141. In an embodiment, the pawl 128 includes a staggard profile 160 having protrusions and recesses to engage with teeth 138 at different levels or thicknesses.
[0082] The second pawl 131 may have a different shape from the first pawl 128. For example, the second pawl 131 may include a notch 164 having a reduced height H2 compared to a firstheight Hl of the first pawl 128. As observed in Fig. 7, the reduced height H2 can allow the pawl 131 to interface with the cam 126 in one or more recesses 142 that accommodate the reduced height H2, thus allowing connection only in predefined angular positions about the first axis II. One skilled in the art will recognize that alternative shapes of the pawls 128, 130 are also contemplated. Additionally, the teeth 138 may have different heights H3, H4 corresponding to one or more recesses 142 of the pawls 128, 131.
[0083] Figs. 8, 9A, and 9B illustrate the angular offset mechanism 114 having a layered configuration. As observed, a first set of pawls 128 is provided at a first layer, and a second set of pawls 130 is provided at a second layer. One skilled in the art will recognize that additional layers may be added depending on the application. The first set of pawls 128 is arranged to be displaced by a first set of teeth 138 to a first angular engagement position for offsetting the angular position when assistive torque is provided by the torque output mechanism 106 about the joint of the user. For example, the first angular position may rotatably connect the engagement cam 126, or mechanism frame 156, and the thigh link 104. The second set of pawls 130 is arranged to be displaced by a second set of teeth 140 to a second angular position for offsetting the angular position when assistive torque is provided by the torque output mechanism 106 about the joint of the user. The first and second sets of pawls 128 and 130 are concentric about the first axis II . Fig. 8 further depicts the selection shaft 124 having a bit 166 arranged to interface with a knob (e.g., knob 168) arranged for the operator to manipulate one or more sets of pawls 128, 130 about the first axis II .
[0084] Fig. 9A depicts the angular offset mechanism 114 wherein the first and second sets of pawls are disengaged from the mechanism frame 156 and are circumferentially aligned with the peripheries of the first and second rotatable members 132, 133. The first rotatable member 132 contains the first set of pawls 128, and the second rotatable member 133 is arranged to contain the second set of pawls 130. In an embodiment, the first rotatable member 132 and second rotatable member 133 are formed as one piece, i.e., as a monolithic element, having multiple levels of cavities to contain the multiple layers of pawls. Alternatively, the first and second rotatable members 132, 133 and separate pieces and held together by fastening means (e.g., screws, pins, bolts). Fig. 9A further depicts the mechanism frame 156 having a fixed- length arm 170 with at least one aperture 172. The first end 118 of the elastic mechanism 112 may be connected to the mechanism frame 156 by the arm 170 through the aperture 172.
[0085] As depicted in Figs. 9A and 9B, the mechanism frame 156 may define varying levels of grooves 144, 145. For example, the first set of pawls 128 is arranged to interface with a firstlayer of grooves 144, and the second set of pawls is arranged to interface with a second layer of grooves 145. Fig. 9B illustrates the first and second sets of pawls 128, 130 in an engaged configuration, wherein the pawls 128, 130 are displaced to engage with the grooves 144, 145 of the mechanism frame 156 between teeth 138, 140 and contact points 141, 143, respectively. As depicted in Fig. 9B, the first set of pawls 128 has a free range of motion within the mechanism frame 156 when arranged in the first angular engagement position, and the second set of pawls 130 has no free range of motion because each pawl 130 is held between teeth 140 and a contact point 143. One skilled in the art will recognize that, depending on the positioning and size of the grooves, the second set of pawls 130 could be provided with a reduced range of motion when the first set of pawls 128 is arranged in the first angular engagement position.
[0086] Advantageously, the angular offset mechanism 114 allows for setting the limit angle (i.e., the transition between free movement and active exoskeleton mode) at a negative hip angle (e.g., the leg pointing backward). With a layered angular offset mechanism 114, the boundaries of the free range of motion setting are not constrained under certain values but can instead be extended and adjusted as needed.
[0087] Fig. 10 illustrates a chart showing disengaged and engaged positions of the layered angular offset mechanism. As observed, when the angular offset mechanism 114 is disengaged, both first and second sets of pawls 128, 130 do not extend beyond the circumferential periphery 148 of the rotatable member 132. During Assist Level 1, the first set of pawls 128 extends beyond the circumferential periphery 148, while the second set of pawls 130 does not. During Assist Level 2, both first and second sets of pawls 128, 130 extend beyond the circumferential periphery 148. Fig. 11 graphically illustrates the translation between assistance level profiles of Assist Level 1 and Assist Level 2. Additionally, the assistance profile or output torque of the assistive torque assembly 102 remains flat at all angles during the disengaged level. As such, the angular offset mechanism 114 acts as an on / off switch to select between disengaged and engaged assistance levels and to further customize or offset the angle at which assistive torque is provided.
[0088] Figs. 12 and 13 include additional illustrations to help the operator understand the mechanics of compensation device 100 as the operator performs squatting and stooping motions. Fig. 12 shows the progression of the assistive torque assembly 102 and the thigh link 104 through squatting 171 and stooping movements 173. The progression of motions extends from a standing position 175 to a full squat 177 and a full bend or stoop 179, with theconfigurations of the assistive torque assembly 102 and the thigh link 104 depicted at each motion throughout both squatting and bending.
[0089] As another example, Fig. 13 illustrates a plot of exemplary output torques (measured in Nm) of the assistive torque assembly 102 across a broad range of joint angles (°) defined as the angle (measured in degrees) between thigh link 104 and assistive torque assembly 102 relative to the initial position (i.e., standing position) of the operator. Assist Level 1 is depicted using the dotted line. In region Al, corresponding to a transparent or free range of motion, no assistive torque is provided up to angle Bl, corresponding to the end of the free range Al. In region Cl, assistive torque increases as a function of the joint angle until angle DI is reached, after which further assistance is not provided. Angle D 1 may correspond to a max flexion angle 0max_FLx permitted by the assistive torque assembly. This may be due to a mechanical stop, e.g., described in U.S. Patent Publication No. 2024 / 0308060 Al and incorporated herein by reference. The increase of the assistive torque in the region Cl may be linear or non-linear depending on the geometry of the assistive torque assembly 102.
[0090] As observed, Assist Level 2 is depicted using a solid line. After translation from Assist Level 1 to Assist Level 2, the output torque (Nm) is shifted by a predetermined angular offset provided by the angular offset mechanism 114. In region A2, corresponding to a transparent or free range of motion, no assistive torque is provided up to an angle B2, less than angle Bl, corresponding to the end of the free range A2. In region C2, assistive torque increases as a function of the joint angle until angle D2 is reached. Angle D2 may correspond to a new or shifted max flexion angle ©max FLx permitted by the assistive torque assembly.
[0091] Additionally, both Assist Level 1 and Assist Level 2 may have the same angle corresponding to a maximum angle of extension 0max_EXT, such that the compensation device 100 arrests the extension of the hip j oint of the operator when the maximum angle of extension 0max_EXT is reached relative to the initial position. For example, the maximum extension angle 0max_EXT may be -40° relative to the initial position of the compensation device 100. However, one skilled in the art would appreciate that virtually any value of the maximum angle of extension ©max EXT may be implemented by embodiments of the present disclosure.
[0092] Figs. 14A and 14B illustrate side views of an engagement cam 126. The engagement cam 126 includes displacement profile 127 used to displace the first end 118 of the elastic mechanism 112 at customized intersection points 180. The displacement profile 127 may have a generally smooth, arcuate curve in a variation. One or more offset profile positions 176, i.e.,of the displacement profile 127, are imposed to define the intersection points 180 of the displacement profile 127 with the first end 118 of the elastic mechanism 112. In an embodiment, the assistive torque assembly 102 may be provided with an additional constraint, such as a track 178 formed as part of the housing 116, against which the first end 118 of the elastic mechanism 112 is further confined. Alternatively, other force components, such as a pivoting rod 181, as depicted in Fig. 14B, or track & slider guide assembly, as depicted in Figs. 15A-15C can be used to allow further customization of the torque profiles. Depending on the displacement profile of the cam(s), a force component normal to the track 178 could be opposite in sign in the two cases.
[0093] In an embodiment, a slot (e.g., track 178) is provided that causes the pin (e.g., sliding pin 119) to move on a fixed curved coordinate while the cam imposes the progression on that coordinate (e.g., the path of the track). The same effect could be obtained by causing a pin to move parallel to itself upon a certain path (e.g., a mechanical slider or a pivoting rod holding the pin). Such cases provide additional shaping restrictions for the path.
[0094] Fig. 15A illustrates a partial cross-sectional view of the assistive torque assembly 102, including a track 178 for the controlled displacement of the elastic mechanism 112, with a torque profile modifier 115. As noted above, the track 178, formed by the housing 116 or an additional element, constrains the first end 118 of the elastic mechanism 112 during the deflection of the elastic mechanism 112 by the torque output mechanism 106. The first end 118 of the elastic mechanism 112 can include a sliding pin 119 configured to slide along the track 178. The track 178 can include first and second regions 182, 184 to receive the first end 118 of the elastic mechanism 112 depending on the selected torque profile, e.g., Mode A versus Mode B.
[0095] As depicted, the torque output mechanism 106 includes at least one auxiliary cam 155 having at least one auxiliary displacement profile 161. The displacement profile 127 is arranged to force the first end 118 of the elastic mechanism 112 into the first region 182 of the track 178 and the auxiliary displacement profile 161 is arranged to force the first end 118 of the elastic mechanism 112 into the second region 184 of the track 178. The torque profile modifier 115 includes a shift lever 122 arranged to adjust the rate of deflection of the elastic mechanism 112 between the displacement profile 127 of the engagement cam 126 and the auxiliary displacement profile 161 of the at least one auxiliary cam 155.
[0096] The rate of deflection of the elastic mechanism 112 by the auxiliary displacement profile 161 of the at least one auxiliary cam 155 in Mode B, relative to angular displacement of the assistive torque assembly 102 about the at least one joint, is greater or less than the rate of deflection by the displacement profile 127 of the engagement cam 126 in Mode A.
[0097] Figs. 15B and 15C illustrate examples of force distribution between the cams, sliding pin, track, and elastic mechanism. Cam reaction force Fc is perpendicular to the cam (either cam 126 or auxiliary cam 155) and points outward from the cam displacement profile (profile 127 or profile 161). The elastic force FE is parallel to the elastic mechanism and is directed away from the spring. The slot wall reaction force FT is perpendicular to the track direction. The orientation of the slot wall reaction force FT depends on which side of the track 178 the pin is pushed against.
[0098] For example, in an embodiment, the engagement cam 126 is biased to force the sliding pin 119 against one side of the track 178. In contrast, the auxiliary cam 155 is biased to push the sliding pin 119 against both sides of the track 178 at different points along the displacement path. This feature allows for the design of a track that is not restricted to a fixed width (fixed path) but instead accommodates a special slot design that considers which of its sides interacts with the engaged cam. This is an option to expand the number of possible resistive profiles achievable with this mechanism.
[0099] Fig. 16 illustrates cross-sectional views of an embodiment of a compensation device between modes of torque profile operation, i.e., between Mode A and Mode B. However, one skilled in the art will recognize that the present disclosure is not limited to two discrete modes. Displacement of the shift lever 122 about the first axis 11 and in a first direction D 1 from a first slot 123 formed in the housing 116 and a second slot 125 formed in the housing 116 results in Mode B of the torque profile. In Mode B, the shift lever 122 positions the engagement cam 126 to move together with the at least one auxiliary cam 155 and to allow deflection of the elastic mechanism 112 by the auxiliary displacement profile 161. Displacement of the shift lever 122 about the first axis II in a second direction D2 from the second slot 125 to the first slot 123 results in Mode A of the torque profile. In Mode A, the shift lever 122 positions the engagement cam 126 to move independently from the at least one auxiliary cam 155 and to allow deflection of the elastic mechanism by the displacement profile 127.
[0100] Fig. 17 illustrates cross-sectional views of an embodiment of a compensation device between Mode A and Mode B of torque profile operation corresponding to the angle 0 ofdisplacement about the first axis II . Angle 0o represents a neutral or resting position where the elastic mechanism 112 is not displaced by torque output mechanism 106. Angle 0o is the same for both Mode A and Mode B. In Mode A, as the angle 0 of displacement increases to a maximum angle 0n, the elastic mechanism 112 is displaced by the engagement cam 126. In contrast, the auxiliary cam 155 remains fixed concerning the housing 116. In Mode B, as the angle 0 of displacement increases, the elastic mechanism 112 is displaced by the auxiliary cam 155, which moves together with the engagement cam 126. As depicted, the rate of displacement of the elastic mechanism 112 varies between Mode A and Mode B. Thus, for the same angle (e.g., angle 02) beyond the neutral position, the deflection rate of the elastic mechanism 112 is greater in Mode B than in Mode A.
[0101] Figs. 18A-19C illustrate an embodiment of atorque profile modifier 115 for the torque output mechanism 106, wherein the engagement cam 126 and at least one auxiliary cam 155, 157 are configured to be coupled and decoupled to switch between torque profile modes. As depicted in Fig. 18A, the shift lever 122 is connected to a transitional cam 186 that contains both the engagement cam 126 and at least one auxiliary cam 155, 157 between radial frames 188, 189. Figs. 18B and 18C illustrate the engagement cam 126 and the auxiliary cams 155, 157 in a decoupled state, wherein the engagement cam 126 is arranged to rotate about the first axis II independently from the auxiliary cams 155, 157. The engagement cam 126 and the at least one auxiliary cam 155 are configured to be coupled together by one or more axial adjustment pins 194, 195, 196. In a decoupled state, a middle axial adjustment pin 196 is arranged to rotate with the engagement cam 126 about the first axis and away from the axial adjustment pins 194, 196 that remain coupled with the auxiliary cams 155, 157.
[0102] Each radial frame 188, 189 defines at least one transitional ramp 190, 191 and at least one sliding surface 192, 193 along which axial adjustment pins 194, 195 translate during rotation of the transitional cam 186 by the shift lever 122 about the first axis II. Each axial adjustment pin 194, 195, 196 is configured to axially adjust along a third axis 13 defined by each axial adjustment pin 194, 195, 196.
[0103] Figs. 19A-19C illustrate the torque profile modifier 115 in Figs. 18A-18C with interlocked cams 126, 155, 157 in Mode B. In Mode B, the sliding surfaces 192, 193 of the radial frames 188, 189 can provide a free range of motion along which the axial adjustment pins 194, 195 and auxiliary cams 155, 157 translate. As depicted in Fig. 19C, the middle axial adjustment pin 196 engages with the engagement cam 126 and the auxiliary cam 157 to couplethe cams 126, 157 together. Similarly, the axial adjustment pin 194 engages with both the engagement cam 126 and auxiliary cam 155 to couple the cams the cams 126, 155 together.
[0104] Figs. 18C and 19C also illustrate how features of both the angular offset mechanism 114 and torque profile modifier 115 are arranged concerning each other. The knob 168 of the angular offset mechanism 114 rotates the selection shaft 124, coupled together by the coaxial pin 134, to control various pawls 128 that are housed by the rotatable member 132. As noted above, the pawls 128 can be rotatable and attached to the rotatable member 132 by pivot pins 136. One or more bearings 159, 169 are provided between the rotatable member 132 and the cams 126, 155, 157 to enable independent operation between the angular offset mechanism 114 and the torque profile modifier 115.
[0105] Figs. 20-23 illustrate an embodiment of an assistive torque assembly 202. One skilled in the art will recognize that principles of operation of the assistive torque assembly 102, including those with like reference numbers (e.g., 114 and 214) and referenced names, can likewise apply to the assistive torque assembly 202. As depicted in Fig. 20, the assistive torque assembly 202 comprises a torque output mechanism 206 arranged to provide assistive torque from an elastic mechanism 212 to a user. The assistive torque assembly 202 includes an assistive regulation device 208. The torque output mechanism 206 includes an angular offset mechanism 214 within a housing 216. The elastic mechanism 212 is arranged between the assistive regulation device 208 and the angular offset mechanism 214. A first end 218 of the elastic mechanism 212 is connected to a mechanism frame 222 of the torque output mechanism 206. In an embodiment, the mechanism frame 222 includes a fixed-length arm 224 having at least one aperture 226 through which a connector bearing 228 is provided to connect the arm 224 and the first end 218 of the elastic mechanism 212. In an embodiment, the housing 216 provides at least one mechanical stop 227 against which the arm 224 may abut to arrest rotation of the mechanism frame 222 about the first axis II .
[0106] As discussed in greater detail below, the assistive torque assembly 202 is provided with various electronic and sensor components to measure or estimate the torque provided to the operator. The assistive torque assembly 202 can include a power switch 240 to turn the electronic elements on and off, a battery 242 to store and release electricity to the various electronic elements, and an electronic board 248 (e.g., printed circuit board) to connect and support the various electronic elements. The electronic board 248 can include a computing unit (e.g., processor). The assistive torque assembly 202 can include a joint encoder 244, encoder gear 246, and Hall sensor 250 connected to the torque output mechanism 206. The Hall sensor250 is provided to detect engagement and the assist mode of the torque output mechanism 206. In an embodiment, the assistive torque assembly 202 further includes an assistance level indicator 252 that provides a (e.g., numerical) representation of the assistance level of torque provided to the operator.
[0107] The second end 220 of the elastic mechanism 212 is connected to the assistive regulation device 208 of the assistive torque assembly 202. The assistive regulation device 208 is independent of the torque output mechanism 206. As such, embodiments of the assistive torque assembly with two or more layers of pawls and embodiments of the assistive torque assembly with two or more cams can be used independently or together.
[0108] The assistive regulation device 208 includes a preloading cam 230 arranged to impose a pre-tension (or pre-compression) on the elastic mechanism 212, thereby increasing the assistance curve. A regulator shaft 232 is provided to rotatably displace the preloading cam 230, wherein rotation of the preloading cam 230 about a fourth axis 14 by the regulator shaft 232 translates a sliding rod 234 of the second end 220 of the elastic mechanism 212 along a displacement channel 236 to vary the level of torque required to modify the level of assistance provided to the operator.
[0109] Fig. 21 illustrates a schematic view of an embodiment of an assistive regulation device 208 in various operational configurations. The assistive regulation device 208 discretely adjusts the level of preloaded force provided by the elastic mechanism 212. In an embodiment, the levels of preloaded force are discretized by the polygonal shape of the regulator shaft 232 connected to the preloading cam 230. The preloading cam 230 can be displaced about the regulator shaft 232, corresponding to the fourth axis 14, at various angles, e.g., angles al, a2, a3, a4. At first angle al (e.g., 0°), the length LI between the sliding rod 234 and the regulator shaft 232 is at a minimum distance. Advantageously, the asymmetric surface profile 238 of the preloading cam 230 allows rotation of the preloading cam 230 beyond 360° to reduce required torque and modify the level of assistance. Angles a2 and a3 are depicted as being less than 360°, whereas angle a4 is greater than 360°. In an embodiment, the maximum rotation angle provided by the preloading cam 230 is up to 450°. Angle a4 corresponds to the maximum distance between the sliding rod 234 and the regulator shaft 232 at length L2. Figs. 22 and 23 illustrate additional views of the assistive torque assembly 202, particularly concerning the various electronic components.
[0110] Fig. 22 illustrates the power switch 240 and assistance level indicator 252. In an embodiment, the electronic board 248 includes a Wi-Fi module and USB port for communication and charging capabilities. Fig. 23 illustrates a joint encoder 244 arranged to measure the joint angle (e.g., between thigh link and assistive torque assembly) using an encoder gear 246. A preloading cam encoder 245 is further provided to measure the position of the preloading cam 230, wherein the position corresponds to the assistance level. A sensor 254 (e.g., angular encoder) can be added to measure the position of the angular offset mechanism 214 to know the status a-priori. This sensor 254 could, therefore, be used to bypass the Hall sensor 250. One or more LED indicators 260 may be provided to indicate power level, assistance level, or another condition of the various electronic components within the housing 216. Fig. 22 further illustrates a first knob 256 arranged for an operator to adjust the angular offset mechanism 214 and a second knob 258 arranged to adjust the assistive regulation device 208.
[0111] Fig. 24 illustrates a cross-sectional view of assistive torque assembly 102, which has various electronic components to determine a mode of torque profile operation. In an embodiment, the assistive torque assembly 102 includes an angular encoder 197 to determine mode position and relative joint angle, either using the position of one or more cams (e.g., cam 126) or on a different axis, via gears (e.g., sensor 254), giving a -priori information. In an embodiment, the assistive torque assembly 102 includes one or more Hall sensors 198 to determine the position of the shift lever 122, also providing a-priori information.
[0112] In an embodiment, the assistive torque assembly 102 includes one or more cam sensors 199 (e.g., Hall sensors) to determine which cam (e.g., cam 126, auxiliary cam 155) engages the elastic mechanism 112. For example, in an embodiment where a cam sensor 199 is placed on each engagement cam 126 and auxiliary cam 155, Mode A is determined via cam sensor 199 when only the engagement cam 126 displaces the elastic mechanism 112. Mode B is determined via cam sensor 199 when both engagement cam 126 and auxiliary cam 155 are moved, and the auxiliary cam 155 displaces the elastic mechanism 112. In this embodiment, the mode determination is based on real-time information rather than a-priori.
[0113] Fig. 25 illustrates a schematic sensor diagram for computing torque provided to the operator by an assistive torque assembly. As depicted, a joint encoder (e.g., joint encoder 244) is provided to read the relative joint angle (0j) between the assistive torque assembly and output (e.g., thigh) link for the operator. A Hall sensor (e.g., sensor 250) is provided to detect the onset / offset of the angular engagement of the spring-loaded mechanism (i.e., disengagementand engagement of the angular offset mechanism 214). By reading the joint angle 0j at the moment TONSET, it is possible to know which Assistance Level (e.g., Assist Level 1 / Assist Level 2) is engaged. Alternatively, a sensor (e.g., sensor 254) could be added to read the position of the assistance selector directly.
[0114] A preloading cam encoder (e.g., encoder 245) is configured to read the current level of assistance (Level), e.g., corresponding to the assistance level indicator 252. Finally, a mode encoder (e.g., angular encoder 197, Hall sensors 198, and / or cam sensors 199) are configured to detect which Mode is selected (e.g., Mode A / Mode B). Instantly delivered torque is computed as the product between joint angle 0j and the resulting stiffness of the elastic mechanism, which is a function of Level, Mode, Assist, and 0j, as K(Levei, Mode, Assist, 9 j). Adsorbed torque (TAJS) for each trunk flexion is computed (for each limb), e.g., using the electronic board 248, as the integral from TONSET to TOFFSET of the instantly delivered torque.
[0115] In an embodiment, the electronic board 248 is configured to compute instantly delivered torque as a product of the angular displacement of the assistive torque assembly 202 about at least one joint and the stiffness of the elastic mechanism 212 as a function of the current level of the assistive torque, the mode of the torque profile modifier 115, the angular engagement position of the angular offset mechanism 114, and the angular displacement of the assistive torque assembly 102 about at least one joint.
[0116] 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 the assistive torque assembly 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.
[0117] 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 exoskeletons under the principles of the present disclosure. The skilled artisan will understand that the features described herein may be adapted to other methods and types of assistive device s / applications.
[0118] 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 assistive torque assembly (102) configured to produce an assistive torque about at least one joint of an operator, the assistive torque assembly (102) comprising: at least one elastic mechanism (112); a torque output mechanism (106) configured to displace a first end (118) of the at least one elastic mechanism (112); and an assistive regulation device (108) configured to preload a level of assistive torque provided by the at least one elastic mechanism (112).
2. The assistive torque assembly (102) of claim 1, wherein the assistive regulation device (108) is connected to a second end (120) of the at least one elastic mechanism (112).
3. The assistive torque assembly (102) of claim 1, wherein the torque output mechanism (106) includes an angular offset mechanism (114) arranged to adjust angular engagement of the assistive torque between the torque output mechanism (106) and the at least one elastic mechanism (112).
4. The assistive torque assembly (102) of claim 3, wherein the angular offset mechanism (114) includes a selection shaft (124) arranged to rotate about a first axis (II) of the at least one joint of the operator and to displace a first set of pawls (128) to a first angular engagement position.
5. The assistive torque assembly (102) of claim 4, wherein the angular offset mechanism (114) includes a second set of pawls (130) for rotatably connecting an engagement cam (126) and a thigh link (104) at a second angular engagement position for offsetting the angular position for when assistive torque is provided by the torque output mechanism (106) about the joint of the operator.
6. The assistive torque assembly (102) of claim 4, wherein both first and second sets of pawls (128, 130) are concentric about the first axis (II), each pawl being rotatable about a pivot pin (136) defined along a second axis (12) that is parallel to the first axis (II).
7. The assistive torque assembly (102) of claim 1, wherein the torque output mechanism (106) includes a torque profile modifier (115) arranged to adjust a rate of deflection of the elastic mechanism (112) by the torque output mechanism (106).
8. The assistive torque assembly (102) of claim 7, wherein the torque profile modifier (115) includes a shift lever (122) arranged to adjust the rate of deflection of the elastic mechanism (112) between a displacement profile (127) of an engagement cam (126) and an auxiliary displacement profile (161) of at least one auxiliary cam (155).
9. The assistive torque assembly (102) of claim 7, wherein a housing (116) defines a track (178) along which the first end (118) of the elastic mechanism (112) is constrained to follow during deflection of the elastic mechanism (112) by the torque output mechanism (106).
10. The assistive torque assembly (102) of claim 8, wherein the assistive torque assembly (102) comprises an electronic board (248) configured to compute instantly delivered torque as a product between angular displacement of the assistive torque assembly (102) about the at least one joint and stiffness of the elastic mechanism (112) as a function of a current level of assistive torque, a mode of the torque profile modifier (115), an angular engagement position of the angular offset mechanism (114), and the angular displacement of the assistive torque assembly (102) about the at least one joint.
11. The assistive torque assembly (102) of claim 1, wherein the assistive regulation device (108) includes a preloading cam (230) arranged to rotate about a fourth axis (14) by a regulator shaft (232) to move a second end (120) of the elastic mechanism (112) away from the torque output mechanism (106).
12. A compensation device ( 100) arranged to provide assistive forces at a hip j oint of an operator of a passive lumbar exoskeleton (10), the compensation device (100) comprising: an assistive torque assembly (102) having a thigh link (104) rotatably connected thereto;wherein the assistive torque assembly (102) includes a torque output mechanism (106) arranged to displace at least one elastic mechanism (112); and an assistive regulation device (108) configured to preload a level of assistive torque provided by the at least one elastic mechanism (112).
13. The compensation device (100) of claim 12, wherein the torque output mechanism (106) includes an angular offset mechanism (114) arranged to adjust angular engagement of the assistive torque between the torque output mechanism (106) and the at least one elastic mechanism (112).
14. The compensation device (100) of claim 13, wherein the angular offset mechanism (114) includes a selection shaft (124) arranged to rotate about a first axis (II) of the hip joint and to displace a first set of pawls (128) to a first angular engagement position.
15. The compensation device (100) of claim 14, wherein the angular offset mechanism (114) includes a second set of pawls (130) arranged concentrically about the first axis (II) and configured to rotatably connect an engagement cam (126) and the thigh link (104) at a second angular engagement position.
16. The compensation device (100) of claim 12, wherein the torque output mechanism (106) includes a torque profile modifier (115) arranged to adjust a rate of deflection of the elastic mechanism (112) by the torque output mechanism (106).
17. The compensation device (100) of claim 12, wherein the assistive torque assembly (102) includes an electronic board (248) configured to compute instantly delivered torque as a product between angular displacement of the assistive torque assembly (102) about the hip joint and stiffness of the elastic mechanism (112) as a function of a current level of assistive torque, a mode of the torque profile modifier (115), and an angular engagement position of the angular offset mechanism (114).
18. The compensation device (100) of claim 12, wherein the assistive regulation device (108) includes a pre loading cam (230) arranged to rotate about a fourth axis (14) by a regulator shaft (232) to vary a preloaded level of assistive torque of the elastic mechanism (112).
19. An exoskeleton (10) comprising the compensation device (100) according to claim 12, wherein the compensation device (100) is configured to be worn by an operator through a physical human-robot interface (pHRI) (14) comprising an upper-body brace (16), a lumbar belt system (18), and a thigh link assembly (20) engageable with a thigh of the operator; and wherein the exoskeleton (10) is configured to transfer assistive torque generated by the assistive torque assembly (102) of the compensation device (100) to the operator to provide assistive forces during bending, stooping, or lifting motions.
20. The exoskeleton (10) of claim 19, wherein the torque output mechanism (106) includes an angular offset mechanism (114) arranged to adjust angular engagement of the assistive torque between the torque output mechanism (106) and the at least one elastic mechanism (112); wherein the angular offset mechanism (114) includes a selection shaft (124) arranged to rotate about a first axis (II) of the hip joint and to displace a first set of pawls (128) to a first angular engagement position.