WO2019136465A1

WO2019136465A1 - Arm supporting exoskeleton with a variable force generator

Info

Publication number: WO2019136465A1
Application number: PCT/US2019/012744
Authority: WO
Inventors: Logan VAN ENGELHOVEN; Homayoon Kazerooni
Original assignee: The Regents Of The University Of California
Priority date: 2018-01-08
Filing date: 2019-01-08
Publication date: 2019-07-11

Abstract

Described herein is an arm supporting exoskeleton, comprising an arm link mechanism. The arm link mechanism comprises a proximal link, a distal link, an arm coupler, and a variable force generator. The distal link is rotatable relative to the proximal link. The arm coupler is adapted to couple an upper arm of a person to the distal link. The variable force generator comprises a first spring and a second spring, configured to create a torque between the proximal link and the distal link. In the first force mode, the variable force generator exhibits a first stiffness rate defined by the first spring that supports the upper arm of the person against gravity forces and. In the second force mode, the variable force generator exhibits a second stiffness rate defined by the first spring and the second spring that supports the upper arm of the person against the gravity forces.

Description

PCT Patent Application

AR!V! SUPPORTING EXQSKELETO WITH A VARIABLE FORCE

GENERATOR

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit under 35 U.S.C § 119(e) of US

Provisional Patent Application No. 62/614,841, entitled: "ARM SUPPORTING EXOSKELETON WITH A VARIABLE FORCE GENERATOR/' filed on 2018-01-08, Docket No. UCSUP017PUS, which is incorporated herein by reference in its entirety for all purposes.

TECHNICAL FIELD

[0002] The present disclosure pertains to the art of support devices for the human arm and, more particularly, to an arm support device configured to reduce the moment on a person's shoulder during arm elevation. The present disclosure is further directed to a variable force generator applied to an arm supporting exoskeleton capable of being selectively transitioned between at least two stiffness rates. Depending on the configuration, these stiffness rates may correspond to high and low stiffness or an on and off mode, wherein on provides a noticeable stiffness, and off provides a substantially small stiffness that just compensates for the mass and friction of the device.

BACKGROUND

[000S] Conventional passive lift devices, mounted to the torso of a person and configured to support the weight of the arm, are not able to automatically cut or substantially reduce assistance when the person intends to rest his/her upper arm at his/her side, or pick a tool from his/her tool belt. Such devices do not provide a sustained range of position where support torque automatically reduces to zero. Except for a few position points, these devices continuously apply lifting forces to a person's upper arm, potentially inhibiting motion and creating discomfort during non-working postures when assist is not desired.

[0004] Methods and devices describes herein provide the person a supporting torque to raise his/her upper arm thereby reducing the human shoulder forces and torques required to raise the upper arm. However, when the person intends to rest his/her upper arm at his/her sides or pick a tool from his/her tool belt, the device here automatically reduces the lifting force to zero (or substantially small value) allowing the wearer to move her/his upper arm freely. During non-working postures, zero (or substantially small) torque is desired to allow free motion of person's upper arm or to allow person's upper arm to rest without the impedance of an applied torque from the assist device. This creates a greater overall comfort for person during non-working postures.

[0005] in embodiments, an arm supporting exoskeleton configured to be coupled to a person comprises: a shoulder base configured to be coupled to a trunk of the person; and an arm link mechanism configured to be coupled to the shoulder base. The arm link mechanism comprises: a proximal link and a distal link configured to rotate relative to each other about a rotating joint and along a first rotational axis substantially orthogonal to a gravity line when the person is standing upright; at least one arm-coupler adapted to couple an upper arm of the person to the distal link; a tensile force generator coupled to the proximal link at a first end of the tensile force generator and coupled to the distal link at a second end of the tensile force generator, the tensile force generator providing a torque to flex the distal link relative to the proximal link; and a protrusion located substantially at the rotating joint. When the distal link extends past a toggle angle, the protrusion constrains the tensile force generator, and the torque provided by the tensile force generator remains substantially small, and when the protrusion does not constrain the tensile force generator, the torque has the tendency to flex the distal link relative to the proximal link, thereby reducing human shoulder forces and torques required to raise the upper arm of the person.

[00G6] in embodiments, an arm supporting exoskeleton configured to be coupled to a person comprises: a shoulder base configured to be coupled to a trunk of the person; and an arm link mechanism configured to be coupled to the shoulder base. The arm link mechanism comprises: a proximal link and a distal link configured to rotate relative to each other about a rotating joint and along a first rotational axis substantially orthogonal to a gravity line when the person is standing upright; at least one arm-coupler adapted to couple an upper arm of the person to the distal link; and a tensile force generator coupled to the proximal link at a first end of the tensile force generator and coupled to the distal link at a second end of the tensile force generator, the tensile force generator providing a torque to flex the distal link relative to the proximal link. When the arm support exoskeiefon is coupled to the person and an angle between the proximal link and the distal link is smaller than a toggle angle, the torque has the tendency to flex the distal link relative to the proximal link, thereby reducing human shoulder forces and torques required to raise the upper arm of the person and imposing reaction forces and torques on the shoulder base. When the angle between the proximal link and the distal link is larger than the toggle angle, the tensile force generator provides a substantially small torque between the proximal link and the distal link, allowing the person to move the upper arm of the person freely.

[0007] In one embodiment, a variable force generator is used at the tensile force generator, or torque generator, attached to an arm link mechanism of an arm supporting exoskeleton to create a torque about a rotating joint that allows for elevation of a person's arm. When a base of the arm supporting exoskeleton is attached to a person's torso and an arm of the arm supporting exoskeleton is attached to a person's arm, the torque created from the variable force generator serves to flex the person's arm and support it against the force of gravity. The variable force generator is configured to create at least two different stiffness rates. When the variable force generator creates a first stiffness, a first torque is applied to the person's arm that is substantially small and allows the person to flex and extend the upper arm with minimal inhibition from the created first torque throughout the range of motion of person's arm. When the variable force generator creates a second stiffness, a second torque is applied to the person's arm that is substantially higher than the first torque mode and serves to support the person's arm against the forces of gravity. [0008] it can be appreciated that while described as a part of an arm supporting exoskeleton, the variable force generator can be applied to create forces and torques across a multitude of joints and in many different applications.

BRIEF DESCRIPTION OF DRAWINGS

[0009] FIG. 1 is a rear perspective view of an assist device, with a person's arm outstretched.

[0010] FIG. 2 is a close-up view of an arm link mechanism.

[0011] FIG. 3 is a close up rear perspective view of an arm link mechanism.

[0012] FIG. 4 is a side view of an assist device, wherein a first angle is less than a toggle angle.

[0013] FIG. 5 is a front perspective view of an arm support exoskeleton, including two arm link mechanisms.

[0014] FIG. 6 is a rear perspective dose up view of an assist device showing a first rotational axis aligning with a person's glenohumeral joint. [0015] FIG. 7 is a rear view of an assist device showing a first rotational axis aligning with a person's glenohumeral joint. [0016] FIG. 8 is a perspective view of an arm link mechanism including a second rotational axis.

[0017] FIG. 9 is a rear dose up view of the second rotational axis of FIG. 8 aligning with a person's glenohumeral joint.

[0018] FIG. 10 is a perspective view of an arm link mechanism containing an arm coupler.

[0019] FIG. 11 is a side section view of a torque generator with an extension spring.

[0020] FIG. 12 is a schematic of a torque generator.

[0021] FIG. 13 is an alternative side section view of a torque generator with an extension spring.

[0022] FIG. 14 is a side section view of a torque generator with a compression spring.

[0023] FIG. 15 is an alternative side section view of torque generator with compression spring.

[0024] FIG. 16 is a front perspective view of a back frame coupled to a lower extremity exoskeieton.

[0025] FIG. 17 is a front perspective view of a back frame coupled to a trunk exoskeleton.

[0026] FIG. 18 is a schematic of a variable force generator.

[0027] FIG. 19 is an axial section view of a variable force generator.

[0028] FIG. 20 is an axial section view of a variable force generator creating a first tensile force.

[0029] FIG. 21 is an axial section view of a variable force generator creating a second tensile force. [0030] FIG. 22 is an axial section view of a variable force generator creating a first compressive force.

[0031] FIG. 23 is a radial section view of a variable force generator with constraining mechanism in first position.

[0032] FIG. 24 is a radial section view of a variable force generator with constraining mechanism in second position

[0033] FIG. 25 is a detailed section view of a variable force generator at a transition position with constraining mechanism in a second position.

[0034] FIG. 26 is a detailed section view of a variable force generator at a transition position with constraining mechanism in a first position.

[0035] FIG. 27 is a detailed section view of a variable force generator creating a second tensile force.

[0036] FIG. 28 is a detailed section view of a variable force generator creating a first tensile force.

[0037] FIG. 29 is an embodiment of a retaining ring type constraining mechanism.

[0038] FIG. 30 is an embodiment of a rotating type constraining mechanism.

[0839] FIG. 31 is an alternate embodiment of a rotating type constraining mechanism.

[0040] FIG. 32 is an embodiment of a hook type constraining mechanism.

[0041] FIG. 33 is an embodiment of an integrated constraining mechanism.

[0042] FIG. 34 is an embodiment of a screw type constraining mechanism.

[0043] FIG. 35 is an embodiment of a clamp type constraining mechanism.

[0044] FIG. 36 is a close up section view of an embodiment of a constraining mechanism and switch.

[0045] FIG. 37 is a close up section view of an alternate embodiment of a constraining mechanism and switch. [0046] FIG. 38 is a dose up section view of an embodiment of a constraining mechanism and wedge element.

[0047] FIG. 39 is a close up section view of an alternate embodiment of a constraining mechanism and wedge element.

[0048] FIG. 40 is a section view of a variable force generator configured to create a first torque.

[0049] FIG. 41 is a section view of a variable force generator configured to create a second torque.

[0050] FIG. 42 is a section view of an alternate embodiment of a variable force generator configured to create a second torque.

[0051] FIG. 43 is a section view of variable force generator configured to create a torque at a first transition angle

[0052] FIG. 44 is a section view of a variable force generator configured to create a torque at a second transition angle.

[0053] FIG. 45 is a perspective view of a variable force generator as part of an arm supporting exoskeleton.

[0054] FIG. 46 is a schematic of a first alternate embodiment of a variable force generator with three stiffness settings.

[0055] FIG. 47 is a section view of a first alternate embodiment of a variable force generator with three stiffness settings

[0056] FIG. 48 is a schematic of a second alternate embodiment of a variable force generator with three stiffness settings.

[0057] FIG. 49 is a section view of a second alternate embodiment of a variable force generator with three stiffness settings.

[0058] FIG. 50 is a schematic of a third alternate embodiment of a variable force generator with three stiffness settings. [0059] FIG. 51 is a section view of a third alternate embodiment of a variable force generator with three stiffness settings.

[0060] FIG. 52 is a schematic of an alternate embodiment of a variable force generator with extension springs. [0061] FIG. 53 is a section view of an alternate embodiment of a variable force generator with extension springs generating a second force.

[0062] FIG 54 is a section view of an alternate embodiment of a variable force generator with extension springs generating a first force.

[0063] FIG. 55 is a section view of an alternate embodiment of a variable force generator with extension springs with a hook type constraining mechanism.

[0064] FIG. 56 is a section view of an alternate embodiment of a variable force generator with extension springs with a rotating type constraining mechanism.

[0065] FIG. 57 is a schematic of a first alternate embodiment of a variable force generator with series springs [0066] FIG. 58 is a section view of a first alternate embodiment of a variable force generator with series springs.

[0067] FIG. 59 is a schematic of a second alternate embodiment of a variable force generator with series springs.

[0068] FIG. 60 is a schematic of a third alternate embodiment of a variable force generator with series springs.

[0069] FIG 61 is a schematic of a fourth alternate embodiment of a variable force generator with series springs.

DETAILED DESCRIPTION

[0070] FIG 1 depicts an embodiment of arm support exoskeieton 100, which may be also referred to as an assist device. Arm support exoskeleton 100 comprises shoulder base 102, which is configured to be coupled to trunk 202 of person 200.

!n some embodiments, shoulder base 102 is substantially located behind person 200, which may be also referred to as a user. Arm support exoskeleton 100 additionally comprises at least one arm link mechanism 104 that is coupled to shoulder base 102. Arm link mechanism 104 comprises at least proximal link 150 and distal link 152 capable of rotation relative to each other along first rotational axis 154. in some embodiments, first rotational axis 154 is orthogonal to the gravity line 208 when person 200 in standing upright. The term "gravity line" should be understood to mean the direction in which gravity acts. First joint 151 represents a hinge, where distal link 152 rotates relative to proximal link 150. Arm support exoskeieton 100 additionally comprises at least one arm coupler 106 that couples upper arm 204 (of person 200) to distal link 152 of arm link mechanism 104. Arm coupler 106 is depicted in FIG. 2. Arm support exoskeieton 100 additionally comprises at least one torque generator 108 configured to create torque 280 between proximal link 150 and distal link 152. A close up view of arm link mechanism 104 is depicted in FIG. 3. Torque 280 in FIG. 1 and FIG. 3 shows the torque imposed on distal link 152 from proximal link 150. As shown in FIG. 4, first angle 193 represents an angle between proximal link 150 and distal link 152. When first angle 193 is smaller than toggle angle 195, as depicted in FIG. 4, torque generator 108 generates torque 280 that has the tendency to flex distal link 152 relative to proximal link 150. The term "toggle angle" should be understood to mean the angle between a first position (e.g., arm is raised) in which proximal link 150 and distal link 152 are collinear, and a second position (e.g., arm is lowered) in which the proximal link 150 and distal link 152 become collinear. The term "flex" should be understood to mean a movement of distal link 152 resulting in the decrease of first angle 193, while the term "extend" as used herein should be understood to mean a movement of distal link 152 resulting in the increase of first angle 193. The torque 280 produces supporting force 212 (shown in FIG. 2 and FIG. 4) onto upper arm 204 by arm coupler 106. This reduces the human shoulder forces and torques required to raise upper arm 204 and imposes set reaction force 214 and reaction torque 215 on shoulder base 102

[0071] FIG. 5 depicts another embodiment of arm support exoskeleton 100 including two arm link mechanisms 104 connected to shoulder base 102, each including at least one torque generator 108 and at least one arm coupler 106. In some embodiments, distal link 152 moves in such a manner that it remains substantially parallel with upper arm 204.

[0072] in some embodiments, as depicted in FIG. 5, shoulder base 102 of arm supporting exoskeleton 100 comprises load bearing structure 112 coupled to arm link mechanism 104 and coupling mechanism 114 that attaches shoulder base 102 to trunk 202 of person 200. Load bearing structure 112 supports reaction forces 214 and reaction torques 215 from arm link mechanisms 104. in some

embodiments, reaction forces 214 and reaction torques 215 transfer to person 200. In some embodiments, as depicted in FIG. 16, reaction forces 214 and reaction torques 215 transfer to a support surface (e.g., ground 310).

[0073] FIG. 6 depicts the close up view of arm link mechanism 104. in this embodiment, first rotational axis 154 of first joint 151 approximately passes through glenohumeral joint 218 of person 200. FIG. 7 depicts a back view of this embodiment wherein arm support exoskeleton 100 contains two arm link mechanisms 104.

[0074] FIG. 8 and FIG. 9 depict another embodiment of arm supporting exoskeleton 100 wherein arm link mechanism 104 comprises at least one horizontal rotation joint 156. Horizontal rotation joint 156 allows proximal link 150 to rotate relative to shoulder base 102 about second rotational axis 155. Second rotational axis 155 is substantially orthogonal to first rotational axis 154. FIG. 9 shows a rear view of the arm link mechanism 104, wherein the second rotational axis 155 is shown to substantially pass through glenohumeral joint 218 of person

200, [0075] FIG. 10 depicts embodiments of arm supporting exoskeieton 100 wherein arm coupler 106 further comprises a load hearing coupler 160 coupled to distal link 152 capable of imposing supporting force 212, directed upward, on upper arm 204 (shown in F!G. 1). in some embodiments, load bearing coupler 160 comprises distal link attachment 167 that attaches arm coupler 106 to distal link 152 and at least one arm cuff 168 that at least partially encircles upper arm 204 (shown in FIG. 1).

[0076] FIG. 10 depicts an embodiment of arm support exoskeieton 100 wherein arm coupler 106 further comprises an arm coupling mechanism 162. Arm coupling mechanism 162 is capable of coupling arm coupler 106 to upper arm 204 (shown in FIG. 2). Arm coupling mechanism 162 may comprise an element or combination of elements selected from a group consisting of rigid, semi-rigid, or compliant materials preventing separation of upper arm 204 (shown in FIG. 1) from arm coupler 106.

[0077] FIG. 11 through FIG. 15 depict various embodiments of arm supporting exoskeieton 100 wherein torque generator 108 comprises tensile force generator 178. Tensile force generator 178, as shown in FIG. 11, is coupled to proximal link 150 from its first tensile end 176 and distal link 152 from its second tensile end 177. The tensile force in tensile force generator 178 provides torque 280 to flex distal link 152 relative to proximal link 150 about first rotational joint 151. In some embodiments of torque generator 108, tensile force generator 178 comprises coil spring element 180. In some embodiments of torque generator 108, tensile force generator 178 comprises line element 182 coupling coil spring element 180 to proximal link 150. Line element 182 comprises an element or combination of elements selected from a group consisting of wire rope, rope, cable, twine, strap, chain, or any combination thereof. In some embodiments of torque generator 108, line element 182 at least partially encircles pulley 183 coupled to distal link 152 before line element 182 is coupled to proximal link 150. In some embodiments pulley 183 does not rotate relative to distal link 152. in some embodiments, pulley 183 is a curved surface incorporated into distal link 152. FIG. 11 depicts an embodiment of torque generator 108 where coil spring element 180 is an extension spring. Coil spring element 180 is coupled to line element 182 at junction 179 and coupled to distal link 152 at second tensile end 177.

[0078] FIG. 12 shows an approximate schematic of torque generator 108. Tensile force generator 178 is coupled to proximal link 150 at first distance 272. Tensile force generator 178 acts about distal link at second distance 270. Tensile force generator effective length 276 is the distance between first distance 272 along proximal link 150 and second distance 270 along distal link 152. Tensile force generator original length is the tensile force generator effective length 276 corresponding to a zero value of first angle 193. Tensile force is a function of spring constant, spring preload, tensile force generator original length, and tensile force generator effective length 276 at a given value of first angle 193. Torque 280 causes distal link to flex relative to shoulder base 102.

[0079] FIG. 13 through FIG. 15 depicts various embodiments of torque generator 108 wherein tensile force generator 178 comprises coil spring element 180 and line element 182. Line element 182 at least partially encircles pulley 183 coupled to distal link 152. FIG. 13 depicts an embodiment of torque generator 108 where coil spring element 180 is an extension spring with a different orientation than shown in FIG. 11. Coil spring element 180 is coupled to line element 182 at junction 179 and coupled to distal link 152 at second tensile end 177. In some embodiments, line element 182 at least partially wraps around pulley 183 attached to distal link 152 before attaching to proximal link 150. FIG. 14 depicts an embodiment of torque generator 108 where coil spring element 180 is a compression spring. Coil spring element 180 is coupled to line element 182 at junction 179 and coupled to distal link 152 at second tensile end 177. In some embodiments, line element 182 at least partially wraps around pulley 183 attached to distal link 152 before attaching to proximal link 150. FIG. 15 depicts an embodiment of torque generator 108 where coil spring element 180 is a compression spring with a different orientation than shown in FIG. 14. Coil spring element 180 is coupled to line element 182 at junction 179 and coupled to distal link 152 at second tensile end 177. In some embodiments, line element 182 at least partially wraps around pulley 183 attached to distal link 152 before attaching to proximal link 150. It is understood that in all embodiments, instead of coil spring element 180, a gas spring, air spring, elastomer, or any combination that exhibits similar behavior can be utilized.

[0080] FIG. 16 depicts an embodiment wherein load bearing structure 112 comprises back frame 130 located substantially behind person 200 and lower extremity exoske!eton 304 coupled to back frame 130 and also coupled to legs 228 of person 200. Back frame 130 is coupled to arm link mechanism 104 and supports at least a portion of reaction forces 214 and reaction torques 215 from arm link mechanism 104. Back frame 130 transfers at least a portion of reaction forces 214 and reaction torques 215 to lower extremity exoskeleton 304. Lower extremity exoskeleton 304 transfers at least a portion of reaction forces 214 and reaction torques 215 to ground 310, resulting in ground reaction forces 311. Exoskeletons can be coupled to arm supporting exoskeletons 100, in accordance with some examples.

[0081] FIG. 17 depicts an embodiment wherein load bearing structure 112 comprises a back frame 130 located substantially behind person 200 and a trunk supporting exoskeieton 302 coupled to back frame 130.

[0082] FIG. 45 depicts a perspective view of arm supporting exoskeleton 100 utilizing variable force generator 401 configured to create a torque about first rotational joint 431 to support gravity forces on upper arm 204 of person 200. in some embodiments variable force generator 401 may be the same as tensile force generator 178 or torque generator 108, and first rotational joint 431 may be designed to rotate along first rotational axis 154. Arm coupler 106 is configured to couple to upper arm 204 and is coupled to distal link 152 or first element 406. Shoulder base 102 is configured to transfer reaction forces and torques from arm coupler 106 to trunk 202 of person 200, and is coupled to rotational base link 430 or proximal link 150. In some embodiments, rotational base link 430 may the same as proximal link 150.

[0083] in one embodiment, a variable force generator creates an "on" and "off" support mode of arm supporting exoskeieton 100. In a first force mode, variable force generator 401 exhibits a substantially small first stiffness and creates a substantially small first force 402, and a substantially small first torque 404 is applied to person's arm that compensates for the mass and friction of the arm supporting exoskeieton 100. A substantially small first torque 404 allows free, relatively unsupported movement of upper arm 204 of person 200. Small reaction forces and torques from first torque 404 are applied to trunk 202 of person through shoulder base 102 or are applied to a lower extremity exoskeieton 304 (not shown). This constitutes the off mode of arm supporting exoskeieton 100. In a second force mode, variable force generator 401 exhibits a second stiffness and creates second force 403 that is substantially larger than first force 402, and second torque 405 substantially larger than first torque 404 is applied to upper arm 204. Second torque 405 supports upper arm 204 from gravitational forces, while reaction forces and torques from second force 403 and second torque 405 are applied to trunk 202 of person 200 through shoulder base 102, or are applied to a lower extremity exoskeieton 304 (not shown). This constitutes the on mode of arm supporting exoskeieton 100.

[0084] in one embodiment, variable force generator creates a "high" and "low" support mode of arm supporting exoskeieton 100. In a first force mode, variable force generator 401 exhibits a first stiffness and creates first force 402, and first torque 404 is applied to upper arm 204, while reaction forces and torques from first force 402 and first torque 404 are applied to trunk 202 of person 200 through shoulder base 102, or are applied to a lower extremity exoskeieton 304 (not shown). First torque 404 supports upper arm 204 from gravitational forces. This constitutes a low support mode of arm supporting exoskeieton 100. In a second force mode, variable force generator 401 exhibits a second stiffness and creates second force 403 that is substantially larger than first force 402, and second torque

405 substantially larger than first torque 404 is applied to upper arm 204. Second torque 405 supports upper arm 204 from gravitational forces, while reaction forces and torques from second force 403 second torque 405 are applied to upper trunk 202 through shoulder base 102, or are applied to a lower extremity exoskeieton 304 (not shown). This constitutes the high support mode of arm supporting exoskeleton 100.

[0085] It can be appreciated that the forces and or torques applied by variable force generator 401 can he applied in a similar manner to a multitude of joints and movement mechanisms of exoskeleton, robotic, or similar applications.

[0086] FIG. 18 shows a schematic embodiment of variable force generator 401. Variable force generator 401 is adaptable to exhibit two stiffness rates between first element 406 and second element 407. In some embodiments, first element

406 may be the same as distal link 152 and second element 407 may be the same as line element 182. Variable force generator 401 comprises first spring 408 that has first end 409 and second end 410. First spring 408 is constrained by first element 406 from its first end 409 and by the second element 407 from its second end 410. Variable force generator 401 further comprises second spring 411 which has first end 412 and second end 413. Second spring 411 is constrained by first element 406 from its first end 412. Variable force generator 401 further comprises at least one constraining mechanism 414 which is configurable to have at least a first position and a second position. FIG. 19 shows a hardware embodiment of variable force generator 401.

[0087] in operation, in the first force mode of variable force generator 401, the constraining mechanism 414 is in its first position as shown in FIG. 20, second end 413 of second spring 411 is not constrained by second element 407. This causes second spring 411 not to affect the motion between first element 406 and second element 407. In this first position the equivalent stiffness is the stiffness of first spring 408. [0088] !n the second force mode of variable force generator constraining mechanism 414 is in its second position as shown in FIG. 21, second end 413 of second spring 411 is constrained by second element 407. This causes the second spring 411 to act in parallel with first spring 408. In this second position, the equivalent stiffness is the addition of both the stiffness of first spring 408 and stiffness of second spring 411.

[0089] In some embodiments, the stiffness of first spring 408 is substantially smaller than the stiffness of second spring 411. When constraining mechanism 414 is in its first position, the motion between first element 406 and second element 407 generates a substantially small force between first element 406 and second element 407 relative to the force generated when constraining mechanism 414 is in its second position. "Substantially small force" is defined as just enough force to overcome the mass and or friction associated with the movement of variable force generator 401. With a substantially small force applied, variable force generator 401 appears to be off, or free moving, to an observer, with little to no spring force discernable. When constraining mechanism 414 is in its second position, the motion between first element 406 and second element 407 generates a force between first element 406 and second element 407 roughly equivalent to the stiffness of second spring 411.

[0090] FIG. 19, FIG. 20, and FIG. 21 show an embodiment wherein first spring 408 further comprises first spring element 442 and first spring bracket 415. First spring element 442 provides the stiffness of first spring 408. First spring element 442 may take the form of a coil spring as shown in all figures, or the form of a gas spring, rubber, or any other type of resilient element with an associated stiffness. First spring bracket 415 serves to facilitate the housing, motion, or general function of constraining mechanism 414 between its first position and second position. First spring bracket 415 may be located at first end 409 or second end 410 of the first spring 408. First spring bracket 415 may further facilitate the coupling of first spring 408 to second element 407. First spring bracket 415 may further facilitate the motion or stabilization of first spring 408 while it is undergoing compression or extension. First spring bracket 415 transfers force between first spring 442 and second element 407. First spring bracket 415 also transfers force between constraining mechanism 414 and second element 407 when constraining mechanism 414 is in its second position.

[0091] FIG. 19, FIG. 20, and FIG. 21 show an embodiment wherein second spring 411 further comprises second spring element 443 and second spring bracket 416. Second spring element 443 provides the stiffness of second spring 411. Second spring element 443 may take the form of a coil spring as shown in all figures, or the form of a gas spring, rubber, or any other type of resilient element with an associated stiffness. Second spring bracket 416 serves to facilitate the housing, motion, or general function of constraining mechanism 414 between its first position and second position. Second spring bracket 416 may be located at the first end 412 or second end 413 of second spring 411. Second spring bracket 416 may further facilitate the motion or stabilization of second spring 411 while it is undergoing compression or extension. Second spring bracket 416 transfers force between second spring element 443 and constraining mechanism 414 when constraining mechanism 414 is in its second position.

[0092] FIG. 20 and FIG. 21 show an embodiment of variable force generator 401 configured to create a tensile force between first element 406 and second element 407. To generate a tensile force, second element 407 may be made of a rigid, semi rigid, or flexible material. In some embodiments, second element 407 comprises a flexible steel cable.

[0093] FIG. 20 shows variable force generator 401 wherein constraining mechanism 414 is in a first position. Second end 413 of second spring 411 is not constrained by second element 407. Therefore, second spring 411 does not affect the motion between first element 406 and second element 407. In this first position, the equivalent stiffness is the stiffness of first spring 408, and variable force generator 401 produces first force 402 between first element 406 and second element 407 that is tensile.

[0094] FIG. 21 shows variable force generator 401 wherein constraining mechanism 414 is in a second position. Second end 413 of second spring 411 is constrained by second element 407. This causes the second spring 411 to act in parallel with first spring 408. in this second position, the equivalent stiffness is the addition of both the stiffness of first spring 408 and stiffness of second spring 411, and variable force generator 401 produces second force 403 between first element 406 and second element 407 that is tensile.

[0095] FIG. 22 shows an embodiment of variable force generator 401 configured to create a compressive force between first element 406 and second element 407 through a re-arrangement of components. Second element 407 may be made of a rigid or semi-rigid material in order to generate a compressive force.

[0096] in FIG. 22, constraining mechanism 414 is in a first position. Second end 413 of second spring 411 is not constrained by second element 407, so second spring 411 does not affect the motion between first element 406 and second element 407. In this first position, the equivalent stiffness is the stiffness of first spring 408, and variable force generator 401 produces a first force 402 between first element 406 and second element 407 that is compressive it can be understood by one skilled in the art that the force produced by any embodiment herein may be made compressive by a similar re-arrangement of components.

[0097] FIG. 23 and FIG. 24 show a radial section of an embodiment wherein first spring 408 and second spring 411 are arranged concentrically. FIG. 23 shows variable force generator 401 wherein constraining mechanism 414 is in a first position. FIG. 24 shows variable force generator 401 wherein constraining mechanism 414 is in a second position. [0098] !n the embodiment of FIG. 23 and FIG. 24, second element 407 is arranged concentrically with one or a combination of the first spring 408, second spring 411, or first element 406.

[0099] in the embodiment of FIG. 23 and F!G. 24, first element 406 comprises a cylindrical opening. First spring 408 and second spring 411 are arranged concentrically within the cylindrical first element 406 while constrained by the cylindrical first element 406 from their respective first ends 409 and 412.

[00100] F!G. 23 and FIG. 24 depict a radial section of variable force generator 401 further comprising orientation sleeve 417. Orientation sleeve 417 is configured to radially constrain first spring 408 relative to second spring 411. The radial constraint may be used to facilitate smooth motion or a bearing surface, or to prevent contact between coils of first spring 408 and second spring 411.

[001G1] FIG. 25, FIG. 26, FIG. 27, and FIG. 28 depict a detailed axial section view of variable force generator 401. Variable force generator 401 may further comprise one or more rotational orientation elements that rotationa!ly constrain first spring 408, second spring 411, orientation sleeve 417, or any combination thereof relative to first element 406. In the embodiment of FIG. 25, first orientation element 418 rotationai!y constrains orientation sleeve 417 relative to first element 406 by means of a pin, although other configurations are possible. Additionally, second orientation element 419 rotationally constrains orientation sleeve 417 relative to first spring bracket 415 by means of a pin, although other configurations are possible.

[00102] In some embodiments, orientation sleeve 417 is configured to radially constrain second spring 411 relative to first element 406. The radial constraint may be used to facilitate smooth motion or a bearing surface, or to prevent contact between coils of second spring 411 and first element 4Q6 [00103] In some embodiments first element 406 acts to radially constrain second spring 411. in still other embodiments, second element 407 acts to radially constrain first spring 408.

[00104] In some embodiments, a number of rotational orientation elements may be used to rotationai!y constrain first spring 408 and or second spring 411 relative to first element 406. Rotational constraints may be necessary to ensure proper positioning of components for the function of constraining mechanism 414 to move between its first position and second position. FIG. 23 shows an embodiment where constraining mechanism 414 further serves to rotationaiiy constrain second spring 411 relative to first element 406 and or orientation sleeve 417 when constraining mechanism 414 is in its first position.

[00105] FIG. 24 shows an embodiment wherein constraining mechanism 414 further serves to rotationaiiy constrain second spring 411 relative to first spring 408 or orientation sleeve 417 when constraining mechanism 414 is in its second position.

[00106] FIG. 25 depicts an embodiment of variable force generator 401 that comprises one or more axial orientation elements that axially constrain first spring 408, second spring 411, orientation sleeve 417, or any combination thereof to first element 406. Axial constraint of first spring 408 and second spring 411 relative to first element 406 serves to remove any forces on constraining mechanism 414 due to the stiffness of first spring 408 or second spring 411. Removing forces on constraining mechanism 414 allows for an easier transition between its first position and second position.

[00107] In embodiment shown in FIG. 25, first orientation element 418 axially constrains orientation sleeve 417, relative to first element 406. Furthermore, first orientation element 418 axially constrains the maximum extension of first spring 408 and second spring 411 relative to first element 406 by means of a pin, although other configurations are possible [00108] In another embodiment, second orientation element 419 axially constrains orientation sleeve 417 relative to first spring 408 by means of a pin and slot configuration, although other configurations are possible.

[00109] The axial position of first orientation element 418 and second orientation element 419 may further be used to preload first spring 408 and or second spring 411 when axially constrained by first orientation element 418 or second orientation element 419. The amount of preload of first spring 408 and or second spring 411 may be manipulated to alter the forces generated by variable force generator 401.

[00110] In some embodiments, variable force generator 401 further comprises preload element 426. Preload element 426 axially constrains first spring 408 and or second spring 411 relative to first element 406 to preload first spring 408 and or second spring 411 when axially constrained against first orientation element 418 and or second orientation element 419. When axially constrained against first orientation element 418, preload element 426 may preload first spring 408 by a different distance than second spring 411. The amount of preload provided by preload element 426 may be used to alter the force profile of variable force generator 401, allow for the use of varying types and or lengths of first spring 408 and or second spring 411, or facilitate proper positioning of components.

[00111] In some embodiments, the axial length of first spring bracket 415 and or second spring bracket 416 act to preload first spring element 442 and or second spring element 443 when axially constrained against first orientation element 418 and or second orientation element 419

[00112] In some embodiments, constraining mechanism 414 is translationally coupled to second spring 411. FIGS. 72 through FIG. 28 show an embodiment of variable force generator 401 wherein constraining mechanism 414 is a pin or t-pin that slides though a hole within second spring 411. Constraining mechanism 414 is configured to slide into a profile, such as a hole or slot, within first spring 408 when constraining mechanism 414 is in its second position. When the constraining mechanism 414 has slid into the hole of first spring 408, the result is that second spring 411 is axially coupled to first spring 408, and thus second element 407, allowing stiffness from both first spring 408 and second spring 411 to be transferred between first element 406 and second element 407.

[00113] FIG. 29 is a radial section view of an alternative embodiment of variable force 401 wherein constraining mechanism 414 is a retaining ring translationally coupled to second spring 411 and configured to lock into a groove on first spring 408 and therefore axially couple first spring 408 to second spring 411.

[00114] In another embodiment [not shown) constraining mechanism 414 may similarly be translationally coupled to first spring 408 and slide into a profile, such as a hole or slot, in second spring 411.

[00115] FIG. 30 is an axial section view of an alternative embodiment of variable force generator 401 wherein constraining mechanism 414 is rotatably coupled to second spring 411. In its second position, constraining mechanism 414 is configured to couple to a profile in the first spring 408 and therefore axially couple second spring 411 to first spring 4Q8 or second element 407. When constraining mechanism 414 is in its second position, stiffness from both first spring 408 and second spring 411 is transferred between first element 406 and second element 407.

[00116] FIG. 31 is an axial section view of an embodiment of variable force generator 401 wherein constraining mechanism 414 is rotatably coupled to first spring 408. in its second position, constraining mechanism 414 is configured to couple to a profile in the second spring 411 and therefore axially couple second spring 411 to first spring 408 or second element 407. When constraining mechanism 414 is in its second position, stiffness from both first spring 408 and second spring 411 is transferred between first element 406 and second element

407. [00117] F!G. 32 is an axial section view of an alternative embodiment of variable force 401 wherein constraining mechanism 414 comprises a pin transiationaily coupled to second spring 411 that can be selectively coupled to a hook that is coupled to or part of first spring 408. When constraining mechanism 414 is in its first position, it cannot couple to the hook. When constraining mechanism 414 is in its second position as shown, it can couple with the hook and therefore axially couple first spring 408 to second spring 411. In another embodiment (not shown), the pin can be rotatably coupled to second spring 411 or the pin and hook combination can be reversed between first spring 408 and second spring 411.

[00118] FIG. 33 shows a radial section view of an embodiment of variable force generator 401 wherein the function of constraining mechanism 414 is embedded in the shape and rotational orientation of second spring 411 relative to first spring 408. in the embodiment, first spring 408 comprises a number of protrusions and second spring 411 comprises a number of profiles allowing the protrusions of first spring 408 to pass through. When the protrusions of first spring 408 and profiles of second spring 411 are aligned, constraining mechanism 414 is in its first position and second spring 411 is not coupled to first spring 408. When second spring 411 is rotated so that the protrusions of first spring 408 and profiles of second spring 411 are not aligned, constraining mechanism 414 is in its second position and first spring 408 is axially coupled to second spring 411. in another embodiment (not shown), the protrusions are on second spring 411 and the profiles are on first spring 408.

[00119] FIG. 34 shows an axial section view of an embodiment of variable force generator 401 wherein the function of constraining mechanism 414 is embedded into the first spring 408 and second spring 411. First spring 408 and second spring 411 each comprise mating threads that allow first spring 408 to be axially coupled to second spring 411 when either is rotated in a manner that engages the threads. FIG. 34 shows the constraining mechanism 414 in a second position wherein the threads between first spring 408 and second spring 411 are engaged. The first position of constraining mechanism 414 would correspond to no threads between first spring 408 and second spring 411 being engaged.

[00120] F!G. 35 shows a radial section view of an embodiment of variable force generator 401 wherein constraining mechanism 414 is a screw or cam that causes second spring 411 to damp, or friction lock, with first spring bracket 408. When constraining mechanism 414 is in its first position, the screw or cam is loose and first spring 408 can freely pass in and out of second spring 411. When constraining mechanism 414 is in its second position, the screw or cam is tightened and first spring 408 is compressed within second spring 411. This feature couples first spring 408 to second spring 411 allowing the stiffness of second spring 411 to be transferred between first element 406 and second element 407.

[00121] It can be appreciated by one skilled in the art that all of the

embodiments of constraining mechanism 414 presented herein can be applied to other spring arrangements described later in this text to constrain any combination of first spring 408, second spring 411, first element 406, or second element 407

[00122] In the embodiment shown in FIG. 25 through FIG. 28, first spring bracket 415 has a profile that when first spring bracket 415 is not constrained to second spring bracket 416, the first spring bracket 415 profile moves constraining mechanism 414 out of the way of first spring bracket 415 (i.e., into first position), aliowing first spring bracket 415 to reach the transition position in the first embodiment, first spring bracket 415 has a chamfered profile but it can be appreciated that other profiles are possible to reach similar results.

[00123] In some embodiments constraining mechanism 414 is made of a magnetic material.

[00124] In the embodiment shown in FIG. 25 through FIG. 28, variable force generator 401 further comprises at least one first magnet 422 coupled to first spring 408 that attracts constraining mechanism 414 into its second position when first spring 408 and second spring 411 are properly aligned with first element 406. When first magnet 422 attracts constraining mechanism 414, it thereby axiaiiy and/or rotationa!ly couples first spring 408 to second spring 411.

[00125] In the embodiment shown in FIG. 25 through FIG. 28, variable force generator 401 further comprises at least one second magnet 423 coupled to first element 406 that attracts constraining mechanism 414 into its first position when first spring 408 and second spring 411 are properly aligned to first element 406. When second magnet 423 attracts constraining mechanism 414, it thereby decouples first spring 408 from second spring 411.

[00126] In some embodiments, the influence of second magnet 423 on constraining mechanism 414 is stronger than the influence of first magnet 422 on constraining mechanism 414. When first spring 408 and second spring 411 are properly positioned relative to first element 406, constraining mechanism 414 will automatically enter a first position.

[00127] In the embodiment shown in FIG. 25 through FIG. 28, variable force generator 401 further comprises switch 420 coupled to at least one second magnet 423 and translationally coupled to first element 406. In another embodiment (not shown), switch 420 may be rotatably coupled for first element 406. Switch 420 can be moved relative to first element 406 between a first position wherein the second magnet 423 does attract the constraining mechanism 414 to a second position wherein the second magnet 423 does not attract the constraining mechanism 414.

[00128] FIG. 25 shows variable force generator 401 at the transition position wherein switch 420 is in its second position. Second magnet 423 does not have influence on constraining mechanism 414; thus, first magnet 422 attracts constraining mechanism 414 to its second position and causes it to couple first spring 408 to second spring 411. Switch 420 can be moved to its second position for any position of first spring 408 and second spring 411, and when first spring 408 and second spring 411 return to the transition position, constraining mechanism 414 will move it its second position. [00129] shows variable force generator 401 at the transition position wherein switch 420 is in its first position. Second magnet 423 attracts constraining mechanism 414 to its first position and causes it to decouple first spring 408 from second spring 411. Switch 420 can be moved to its first position for any position of first spring 408 and second spring 411, and when first spring 408 and second spring 411 return to the transition position, constraining mechanism 414 will move it its first position. In some embodiments first element 406 further comprises cover 421 for switch 420.

[00130] FIG. 36 shows another embodiment of variable force generator 401 wherein switch 420 further comprises a holding magnet 453. The influence of holding magnet 453 on constraining mechanism 414 is weaker than the influence of first magnet 422 on constraining mechanism 414. Thus, when both the holding magnet 453 and first magnet 422 are exposed to constraining mechanism 414, constraining mechanism 414 will transition to a second position. Holding magnet 453 is exposed to constraining mechanism 414 when switch 420 is at a second position. Holding magnet 453 holds constraining mechanism 414 out of the way of first spring 408, allowing first spring 408 to reach a transition position. Thus when first spring 408 reaches the transition position, constraining mechanism 414 will automatically move to its second position.

[00131] FIG. 37 shows an embodiment wherein constraining mechanism 414 houses a third magnet 444 and wherein switch 420 comprises fourth magnet 445 and fifth magnet 446. Fourth magnet 445 is configured to attract third magnet 444 housed in constraining mechanism 414. When switch 420 is positioned so that fourth magnet 445 attracts third magnet 444, constraining mechanism 414 moves to a first position wherein first 408 is decoupled from second spring 411. Fifth magnet 446 is configured to repel third magnet 444 housed in constraining mechanism 414. When switch 420 is positioned so that fifth magnet 446 repels third magnet 444, constraining mechanism 414 moves to a second position wherein first spring 408 is coupled to second spring 411. [00132] It can be appreciated by one skilled in the art that for any of the embodiments herein, the movement of constraining mechanism 414 relative to first spring 408 or second spring 411 may be similarly biased by a spring to cause constraining mechanism 414 to move to a first position or a second position.

[00133] FIG. 38 shows an embodiment of variable force generator 401 further comprising wedge element 429. Wedge element 429 forces constraining mechanism 414 into a second position in the event that constraining mechanism 414 is caught between first and second position and is therefore coupling first element 406 to second element 407. This prevents variable force generator 401 from locking first element 406 to second element 407.

[O0134] FIG. 39 shows an embodiment of variable force generator 401 wherein wedge element 429 is a contoured surface of constraining mechanism 414.

[00135] FIG. 40 depicts an axial section view of variable force generator 401 configured to create a torque about first rotational joint 431. First rotational joint 431 is formed between first element 406 and rotational base link 430. In the embodiment, variable force generator 401 further comprises pulley 432 attached to first element 406 that routes flexible second element 407 to a rotational coupling with rotational base link 430. In the embodiment shown, constraining mechanism 414 is in a first position wherein first spring 408 is decoupled from second spring 411. First force 402 is created between first element 406 and second element 407 and thus first torque 404 is created between first element 406 and rotational base link 430 about first rotational joint 431.

[00136] FIG. 41 depicts variable force generator 401 of FIG. 27 wherein constraining mechanism 414 is in its second position and wherein first spring 408 is coupled to second spring 411. A second force 403 is created between first element 406 and second element 407 and thus second torque 4Q5 is created between first element 4Q6 and rotational base link 430 about first rotational joint 431. [00137] When the proper position {radially, axially, and/or rotationaliy) is achieved between first spring 408, second spring 411, and first element 406, a transition position is achieved wherein there are no forces acting on constraining mechanism 414 This allows constraining mechanism 414 to more easily transition variable force generator 401 between first force mode and second force mode.

[00138] FIG. 23, FIG. 24, FIG. 25, and FIG. 26 show variable force generator 401 in transition position wherein all forces acting on constraining mechanism 414 due to first spring 408 and or second spring 411 facilitate ease of motion of constraining mechanism 414. FIG. 24 and FIG. 25 show constraining mechanism 414 is in its second position. FIG. 23 and FIG. 26show constraining mechanism 414 in its first position.

[00139] FIG. 43 depicts variable force generator 401 of FIG. 40 and and FIG. 41 at the transition position, resulting in transition angle 427 between first element 406 and rotational base link 430. When an angle of first element 406 relative to rotational base link 430 is smaller than first transition angle 427, flexible second element 407 goes slack and variable force generator 401 does not generate a force or torque about first rotational joint 431. When an angle of first element 406 relative to rotational base link 430 is larger than first transition angle 427, variable force generator 401, depending on the position of constraining mechanism 414, generates either first force 402 and thus first torque 404 or second force 403 and thus second torque 405.

[00140] In some embodiments, it is possible to change the length of second element 407 by means of its coupling to first spring 408. In the embodiment of FIGS. 92 and 93, this is done by threaded end 425 on second element 407 meshing with a female thread on first spring bracket 415.

[O0141] FIG. 44 depicts variable force generator 401 of FIG. 40 at the transition position. The length of second element 407 has been increased relative to FIG. 43 resulting in a larger transition angle 427. it can be appreciated by one skilled in the art that the length of second element 407 may be increased or decreased to increase or decrease the transition angle 427.

[00142] In other embodiments (not shown), second element 407 may have a similar screw connection with rotational base link 430 to achieve the same adjustment to transition angle 427. In still other embodiments, second element 407 may comprise the ability to change length, such as with a turnbuckle, without an adjustable connection to first spring 408 or rotational base link 430 to achieve the same adjustment to transition angle 427.

[00143] FIG. 42 depicts an axial section view of an alternative embodiment of variable force generator 401 configured to create a torque about first rotational joint 431 formed between first rotating link 434 and rotational base link 430. First element 406 is rotatably and/or translationally coupled to first rotating link 434, and second element 407 is rotationally and/or translationally coupled to rotational base link 430. in the embodiment shown, constraining mechanism 414 is in its second position wherein first spring 408 is coupled to second spring 411. Second force 403 is created between first element 406 and second element 407 and thus second torque 405 is created between first element 406 and rotational base link 430 about first rotational joint 431.

[0O144] In some embodiments, variable force generator 401 may be mounted to the shoulder base 102 of arm supporting exoskeleton 100 and transfer forces to the arm link mechanism 104 by means of control cables. This be done to move the mass of the arm supporting exoskeleton 100 as close to the torso as possible. The control cables may be situated as to not inhibit motion of the arm link mechanism 104 or shoulder base 102.

[00145] FIG. 52 shows a schematic embodiment of variable force generator 401 designed to utilize extension springs rather than compression springs as previously shown. Variable force generator 401 is adaptable to exhibit two stiffness rates between first element 406 and second element 407. Variable force generator 401 comprises first spring 408 that has first end 409 and second end 410. First spring 408 is constrained by first element 406 from its first end 409 and by the second element 407 from its second end 410. Variable force generator 401 further comprises second spring 411 which has first end 412 and second end 413. Second spring 411 is constrained by second element 407 from its second end 413. Variable force generator 401 further comprises at least one constraining mechanism 414 which is configurable to have at least a first position and a second position. FIG. 53 shows a hardware embodiment of variable force generator 401.

[00146] In operation, when the constraining mechanism 414 is in its first position, as shown in FIG. 54, first end 412 of second spring 411 is not constrained by first element 406. This causes second spring 411 not to affect the motion between first element 406 and second element 407. In this first position, the equivalent stiffness is the stiffness of first spring 408.

[00147] When constraining mechanism 414 is in its second position as shown in FIG. 53, first end 412 of second spring 411 is constrained by first element 406. This causes the second spring 411 to act in parallel with first spring 408. In this second position, the equivalent stiffness is the addition of both the stiffness of first spring 408 and stiffness of second spring 411.

[00148] FIG. 53 and FIG. 54 depict a translational coupling arrangement of constraining mechanism 414 between second spring 411 and first element 406 similar in function to the embodiment of FIG. 19, the only difference being between the two components constrained by constraining mechanism 414.

[00149] FIG. 55 depicts a pin and hook arrangement of constraining mechanism 414 between second spring 411 and first element 406 similar in form to the embodiment of FIG. 32, the only difference being between the two components constrained by constraining mechanism 414.

[00150] F!G. 56 depicts a rotatable coupling arrangement of constraining mechanism 414 between second spring 411 and first element 406 similar in form to the embodiment of FIG. 31, the only difference being between the two components constrained by constraining mechanism 414.

[00151] It can be appreciated by one skilled in the art that all of the

embodiments of constraining mechanism 414 presented herein can be applied to other spring arrangements described later in this text to constrain any combination of first spring 408, second spring 411, first element 406, or second element 407.

[00152] FIG. 57 shows a schematic embodiment of variable force generator 401 utilizing first spring 408 and second spring 411 in series. Variable force generator 401 is adaptable to exhibit two stiffness rates between first element 406 and second element 407. Variable force generator 401 comprises first spring 408 that has first end 409 and second end 410. First spring 408 is constrained by first element 406 from its first end 409 and by the second spring 411 from its second end 410. Variable force generator 401 further comprises second spring 411, which has first end 412 and second end 413. Second spring 411 is constrained by first spring 408 from its first end 412 and by second element 407 from its second end. Variable force generator 401 further comprises at least one constraining mechanism 414, which is configurable to have at least a first position and a second position. FIG. 58 shows a hardware embodiment of this embodiment of variable force generator 401.

[00153] In operation, when the constraining mechanism 414 is in its first position, first end 412 of second spring 411 is not constrained by first element 406. This causes second spring 411 to act in series with first spring 411. In this first position, the equivalent stiffness is the stiffness of first spring 408 and second spring 411 in series in this first position, the equivalent deflection is the deflection of first spring 408 and second spring 411 in series. When constraining mechanism 414 is in its second position, first end 412 of second spring 411 is constrained by first element 406. This causes the second spring 411 to act alone. In this second position, the equivalent stiffness is the stiffness of second spring 411, and the equivalent deflection is the deflection of second spring 411. In the series combination shown, first spring 408 or second spring 411 may be compression or extension springs

[00154] F!G. 59 shows an alternative embodiment of variable force generator 401 with first spring 408 and second spring 411 in series. Variable force generator 401 is adaptable to exhibit two stiffness rates between first element 406 and second element 407. Variable force generator 401 comprises first spring 408 that has first end 409 and second end 410. First spring 408 is constrained by second spring 411 from its first end 409 and by the second element 407 from its second end 410. Variable force generator 401 further comprises second spring 411, which has first end 412 and second end 413. Second spring 411 is constrained by first element 406 from its first end 412 and by first spring 408 from its second end 413. Variable force generator 401 further comprises at least one constraining mechanism 414, which is configurable to have at least a first position and a second position.

[00155] In operation, when the constraining mechanism 414 is in its first position, second end 413 of second spring 411 is not constrained by second end 410 of first spring 408 This causes second spring 411 to act in series with first spring 408. in this first position, the equivalent stiffness is the stiffness of first spring 408 and second spring 411 in series. In this first position, the equivalent deflection is the deflection of first spring 408 and second spring 411 in series.

When constraining mechanism 414 is in its second position, second end 413 of second spring 411 is constrained by second end 410 of first spring 408. This causes the second spring 411 to act alone. In this second position, the equivalent stiffness is the stiffness of second spring 411, and the equivalent deflection is the deflection of second spring 411.

[00156] FIG. 60 shows an alternative embodiment of variable force generator 401 with first spring 408 and second spring 411 in series. Variable force generator 401 is adaptable to exhibit two stiffness rates between first element 406 and second element 407. Variable force generator 401 comprises first spring 408 that has first end 409 and second end 410. First spring 408 is constrained by second spring 411 from its first end 409 and by the second element 407 from its second end 410. Variable force generator 401 further comprises second spring 411, which has first end 412 and second end 413. Second spring 411 is constrained by first element 406 from its first end 412 and by first spring 408 from its second end 413. Variable force generator 401 further comprises at least one constraining mechanism 414, which is configurable to have at least a first position and a second position.

[00157] In operation, when the constraining mechanism 414 is in its first position, second end 413 of second spring 411 is not constrained by first element 406. This causes second spring 411 to act in series with first spring 411. In this first position, the equivalent stiffness is the stiffness of first spring 408 and second spring 411 in series. In this first position, the equivalent deflection is the deflection of first spring 408 and second spring 411 in series. When constraining mechanism 414 is in its second position, second end 413 of second spring 411 is constrained by first element 406. This causes the first spring 408 to act alone. In this second position, the equivalent stiffness is the stiffness of first spring 408, and the equivalent deflection is the deflection of first spring 408.

[O0158] FIG. 61 shows a schematic embodiment of a variable force generator 401 utilizing first spring 408 and second spring 411 in series. Variable force generator 401 is adaptable to exhibit two stiffness rates between first element 406 and second element 407. Variable force generator 401 comprises first spring 408 that has first end 409 and second end 410. First spring 408 is constrained by first element 406 from its first end 409 and by the second spring 411 from its second end 410. Variable force generator 401. further comprises second spring 411, which has first end 412 and second end 413. Second spring 411 is constrained by first spring 408 from its first end 412 and by second element 407 from its second end. Variable force generator 401 further comprises at least one constraining mechanism 414, which is configurable to have at least a first position and a second position

[00159] In operation, when the constraining mechanism 414 is in its first position, second end 413 of second spring 411 is not constrained by second end 410 of first spring 408. This causes second spring 411 to act in series with first spring 411. in this first position, the equivalent stiffness is the stiffness of first spring 408 and second spring 411 in series in this first position, the equivalent deflection is the deflection of first spring 408 and second spring 411 in series.

[00160] When constraining mechanism 414 is in its second position, second end 413 of second spring 411 is constrained by second end 410 of first spring 408. This causes the first spring 408 to act alone in this second position, the equivalent stiffness is the stiffness of first spring 408, and the equivalent deflection is the deflection of first spring 408.

[00161] FIG. 46 shows a schematic embodiment of variable force generator 401. Variable force generator 401 is adaptable to exhibit three stiffness rates between first element 406 and second element 407. Variable force generator 401 comprises first spring 408 that has a first end 409 and second end 410. First spring 408 is constrained by first element 406 from its first end 409 and by the second element 407 from its second end 410. Variable force generator 401 further comprises two second springs 411 which have first end 412 and second end 413. Second springs 411 are constrained by first element 406 from their first end 412. Variable force generator 401 further comprises at least two constraining mechanisms 414 which are configurable to have at least a first position and a second position. FIG. 47 shows a hardware embodiment of variable force generator 401.

[0O162] In operation, when both constraining mechanisms 414 are in their first position, second end 413 of both second springs 411 are not constrained by second element 407. This causes second springs 411 not to affect the motion between first element 406 and second element 407. In this first position, the equivalent stiffness is the stiffness of first spring 408.

When one constraining mechanism 414 is in its second position and one constraining mechanism 414 is in its first position, second end 413 of one second spring 411 is constrained by second element 407 and second end 413 of the other second spring 411 is not constrained by second element 407. This causes one second spring 411 to act in parallel with first spring 408. in this second position, the equivalent stiffness is the addition of both the stiffness of first spring 408 and stiffness of one second spring 411. When both constraining mechanisms 414 are in their second position, second end 413 of both second springs 411 are constrained by second element 407. This causes both second springs 411 to act in parallel with first spring 408. in this second position, the equivalent stiffness is the addition of both the stiffness of first spring 408 and stiffness of both second springs 411.

[00163] It may be appreciated by one skilled in the art that a greater number of second springs 411 may be added to increase the number of stiffness rates between first element 406 and second element 407.

[00164] FIG. 48 shows a schematic embodiment of variable force generator 401. Variable force generator 401 is adaptable to exhibit three stiffness rates between first element 406 and second element 407. Variable force generator 401 comprises first spring 408 that has a first end 409 and second end 410. First spring 408 is constrained by first element 406 from its first end 409 and by the second element 407 from its second end 410. Variable force generator 401 further comprises second spring 411, which has first end 412 and second end 413. Second spring 411 is constrained by first element 406 from its first end 412. Variable force generator further comprises third spring 447 which has first end 448 and second end 449. Third spring 447 is constrained by first element 406 from its first end 448. Variable force generator 401 further comprises constraining mechanism 414, which is configurable to have at least a first position and a second position.

Variable force generator further comprises a second constraining mechanism 452, which is configurable to have at least a first position and a second position. [00165] F!G. 49 shows a hardware embodiment of variable force generator 401 wherein first spring 408 further comprises first spring element 442 and first spring bracket 415, second spring 411 further comprises second spring element 443 and second spring bracket 416, and third spring 447 further comprises third spring element 450 and third spring bracket 451. The function of each spring element is to provide the stiffness of the respective spring. The function of each spring bracket is to transfer force, facilitate the housing, motion, or general function of constraining mechanism 414 or second constraining mechanism 452, facilitate the coupling between components, or facilitate the motion or stabilization of its respective spring.

[00166] In operation, when constraining mechanism 414 is in its first position, second end 413 of second spring 411 and of third spring 447 are not constrained by second element 407. This causes second spring 411 and third spring 447 not to affect the motion between first element 406 and second element 407. In this first position, the equivalent stiffness is the stiffness of first spring 408. When constraining mechanism 414 is in its second position and second constraining mechanism 452 is in its first position, second end 413 of second spring 411 is constrained by second element 407 and second end 413 of third spring 447 is not constrained by second element 407. This causes second spring 411 to act in parallel with first spring 408. in this second position, the equivalent stiffness is the addition of both the stiffness of first spring 408 and stiffness of one second spring 411. When constraining mechanisms 414 and second constraining mechanism 452 are in their second positions, second end 413 of second springs 411 and of third spring 447 are constrained by second element 407. This causes second spring 411 and third spring 447 to act in parallel with first spring 408. In this second position, the equivalent stiffness is the addition of the stiffness of first spring 408 the stiffness of second springs 411, and the stiffness of third spring 447.

[00167] FIG. 50 shows a schematic embodiment of variable force generator 401. Variable force generator 401 is adaptable to exhibit three stiffness rates between first element 406 and second element 407. Variable force generator 401 comprises first spring 408 that has first end 409 and second end 410. First spring 408 is constrained by first element 406 from its first end 409 and by the second element 407 from its second end 410. Variable force generator 401 further comprises second spring 411, which has first end 412 and second end 413. Second spring 411 is constrained by first element 406 from its first end 412. Variable force generator further comprises third spring 447, which has first end 448 and second end 449. Third spring 447 is constrained by first element 406 from its first end 448. Variable force generator 401 further comprises constraining mechanism 414, which is configurable to have at least a first position, a second position, and a third position.

[00168] FIG. 51 shows a hardware embodiment of variable force generator 401 wherein first spring 408 further comprises first spring element 442 and first spring bracket 415, second spring 411 further comprises second spring element 443 and second spring bracket 416, and third spring 447 further comprises third spring element 450 and third spring bracket 451. The function of each spring element is to provide the stiffness of the respective spring. The function of each spring bracket is to transfer force, facilitate the housing, motion, or general function of constraining mechanism 414, facilitate the coupling between components, or facilitate the motion or stabilization of its respective spring.

[00169] In operation, when constraining mechanism 414 is in its first position, second end 413 of second spring 411 and of third spring 447 are not constrained by second element 407. This causes second spring 411 and third spring 447 not to affect the motion between first element 4Q6 and second element 407. In this first position, the equivalent stiffness is the stiffness of first spring 408. When constraining mechanism 414 is in its second position, second end 413 of second spring 411 is constrained by second element 407 and second end 413 of third spring 447 is not constrained by second element 4Q7. This causes second spring 411 to act in parallel with first spring 408. in this second position, the equivalent stiffness is the addition of both the stiffness of first spring 408 and stiffness of one second spring 411. When constraining mechanisms 414 is in a third position, second end 413 of second springs 411 and of third spring 447 are constrained by second element 407. This causes second spring 411 and third spring 447 to act in parallel with first spring 408. In this third position, the equivalent stiffness is the addition of the stiffness of first spring 408, the stiffness of second springs 411, and the stiffness of third spring 447.

[00170] It can be understood that the various embodiments of spring element arrangements and types of spring elements described can be combined to form embodiments with multiple force modes not explicitly described herein, and that the mechanisms described herein can be modified by a rearrangement of parts to selectively couple first 406, second element 407, first spring 408, second spring 411, first spring bracket 415, second spring bracket 416 or any combination thereof to accomplish multiple stiffness rates of the variable force generator 401 as described in through various series and parallel spring arrangements with compression and extension spring elements.

Claims

What is claimed is:

1. An arm supporting exoskeleton comprising an arm link mechanism, the arm link mechanism comprising:

a proximal link;

a distal link, configured to rotate relative to the proximal link around a first rotational axis;

an arm coupler, attached to the distal link and configured to couple an upper arm of a person to the distal link; and

a variable force generator, comprising a first spring and a second spring, configured to create a torque between the proximal link and the distal link, and is configured to generate at least a first stiffness rate and a second stiffness rate, wherein:

when the variable force generator is in a first force mode, the variable force generator generates the first stiffness rate defined by the first spring that supports the upper arm of the person against gravity forces and,

when the variable force generator is in second force mode, the variable force generator generates the second stiffness rate defined by the first spring and the second spring that supports the upper arm of the person against the gravity forces.

2. The arm supporting exoskeleton of claim 1,

wherein the variable force generator is configured to generate at least the first stiffness rate and the second stiffness rate between a first element and a second element,

wherein the first spring having a first end and a second end, the first spring constrained by the first element from the first end and by the second element from the second end the second spring having a first end and a second end, the second spring constrained by the first element from the first end;

a constraining mechanism configurable to have at least a first position and a second position, wherein:

when the constraining mechanism is in the first position, the second end of the second spring is not constrained by the second element causing the second stiffness rate not to affect motion between the first element and the second element and

when the constraining mechanism is in the second position, the second end of the second spring is constrained by the second element causing the second stiffness rate to act in parallel with the first spring and to affect the motion between the first element and the second element.

3. The arm supporting exoskeleton of claim 2,

wherein the first stiffness rate of the first spring is substantially smaller than the second stiffness rate of the second spring, and

wherein when constraining mechanism is in the first position, the motion between the first element and the second element generates a substantially small force between the first element and the second element and variable force generator allows free, relatively unsupported motion of the upper arm of the person.

4. The arm supporting exoskeleton of claim 2,

wherein the first spring further comprises a first spring element and a first spring bracket, and

wherein the first spring element provides the first stiffness rate of the first spring, and

wherein the first spring bracket is coupled to the first spring and transfers force between the first spring and the second element, and also transfers force between the constraining mechanism and the second element when the constraining mechanism is in the second position.

5. The arm supporting exoskeleton of claim 2,

wherein the second spring further comprises a second spring element and a second spring bracket,

wherein the second spring element provides the second stiffness rate of the second spring, and

wherein the second spring bracket is coupled to the second spring element and transfers force between the second spring element and the constraining mechanism.

6. The arm supporting exoskeleton of claim 0, wherein the arm supporting exoskeieton is configured to create a tensile force between the first element and the second element.

7. The arm supporting exoskeleton of claim 2,

wherein the first element is a cylindrical first element,

wherein the first spring and the second spring are arranged concentrically within the cylindrical first element and constrained by the cylindrical first element from the first end, and

wherein the second element comprises a line passing through cylindrical first element.

8. The arm supporting exoskeleton of claim 1, wherein the variable force generator comprises an orientation sleeve that radially constrains the first spring relative to the second spring.

9. The arm supporting exoskeieton of claim 8, wherein the variable force generator a first orientation element that rotational!y constrains the orientation sleeve relative to the first element

10. The arm supporting exoskeieton of claim 8, wherein the variable force generator a second orientation element that rotationai!y constrains the first spring relative to the orientation sleeve.

11. The arm supporting exoskeieton of claim 2, wherein the constraining mechanism rotationaliy constrains the second spring relative to the first element in the first position

12. The arm supporting exoskeieton of claim 2, wherein the constraining mechanism rotationaliy constrains the second spring relative to the first spring in the second position.

13. The arm supporting exoskeieton of claim 2, wherein the variable force generator comprises an orientation sleeve that radially constrains the first spring relative to the second spring, and

wherein the variable force generator comprises a first orientation element that axially constrains the first element to the orientation sleeve, the first spring, the second spring, or any combination thereof.

14. The arm supporting exoskeieton of claim 13, wherein at least one of the first spring or the second spring is preioaded when constrained by the first orientation element.

15. The arm supporting exoskeieton of claim 13, wherein the variable force generator comprises a preload element that axially constrains the first element to at least one of the first spring or the second spring and is configured to preload at least one of the first spring or the second spring when constrained relative to the first orientation element

16. The arm supporting exoskeleton of claim 2, wherein the constraining mechanism is translational!y coupled to the second spring and configured to slide into a profile within first spring and couple the first spring to the second spring in a manner that transfers the second stiffness rate of the second spring to at least one of the first spring of the second element.

17. The arm supporting exoskeleton of claim 2, wherein the first spring comprises a contoured surface that forces the constraining mechanism to the first position, allowing the first spring to align with the second spring at a transition position.

18. The arm supporting exoskeieton of claim 2, wherein the constraining mechanism is made of a magnetic material.

19. The arm supporting exoskeleton of claim 2, wherein the first spring further comprises a first magnet that attracts the constraining mechanism into the second position.

20. The arm supporting exoskeleton of claim 19, wherein the first element further comprises a second magnet that attracts the constraining mechanism.

21. The arm supporting exoskeleton of claim 20, wherein influence of the second magnet on the constraining mechanism is stronger than influence of the first magnet on the constraining mechanism for all positions of the constraining mechanism.

22. The arm supporting exoskeleton of claim 20,

wherein the first element further comprises a switch, and wherein the switch is positioned relative to the first element at a first switch position where second magnet attracts the constraining mechanism to a second switch position where the second magnet does not attract the constraining mechanism.

23. The arm supporting exoskeieton of claim 2, wherein the constraining mechanism comprises a contoured surface that forces the constraining mechanism into the second position if the constraining mechanism is caught between a first switch position corresponding and a second switch position as the first spring and the second spring begin to compress.

24. The arm supporting exoskeleton of claim 2, wherein when the first spring and the second spring are positioned relative to the first element, a transition position is achieved wherein there are no forces acting on the constraining mechanism, allowing the constraining mechanism to transition between the first position and the second position or from the second position to the first position.

25. The arm supporting exoskeleton of claim 24, wherein an angle between the proximal link and the first element when the first spring and second spring of variable torque generator are at a transition position comprises a transition angle.

26. The arm supporting exoskeieton of claim 25, wherein a length of the second element between the first spring and the proximal link is adjustable to alter the transition angle.

27. The arm supporting exoskeieton of claim 26, wherein a length of the second element is adjustable using a screw connection with the first spring.

28. The arm supporting exoskeieton of claim 1, further comprising a shoulder base, for attaching to a trunk of the person.

29. The arm supporting exoskeleton of claim 2, configured to create a compressive force between first element and second element.

30. An arm supporting exoskeieton comprising an arm link mechanism, the arm link mechanism comprising:

a proximal link;

an arm coupler, attached to the distal link and adapted to couple an upper arm of a person to the distal link; and

a variable force generator, comprising a first spring and a second spring configured to create a torque between proximal link and the distal link and adaptable to exhibit at least a first stiffness rate and a second stiffness rate, wherein:

when variable force generator is in a first force mode, the variable force generator exhibits the first stiffness rate defined by the first spring that allows free, relatively unsupported motion of the upper arm of the person, and

when variable force generator is in second force mode it exhibits the second stiffness rate defined by the first spring and the second spring that supports the upper arm of the person against gravity forces.