Ergonomic exoskeleton system for the upper limb

Abstract

Exoskeleton kinematic chain arranged to pivotally connect a first element to a second element, said first element comprising two pivot points A.sub.1 and B.sub.1 located at a distance A.sub.1B.sub.1, said second element comprising two pivot points A.sub.2 and B.sub.2 located at a distance A.sub.2B.sub.2. The exoskeleton kinematic chain comprises a first external link pivotally connected to the first element at the pivot point A.sub.1 and a first end link pivotally connected to the first external link at a pivot point D.sub.1, said pivot point D.sub.1 being located at a distance A.sub.1D.sub.1 by the pivot point A.sub.1. The exoskeleton kinematic chain comprises then a second external link pivotally connected to the second element at the pivot point A.sub.2, and a second end link pivotally connected to the second external link at a pivot point D.sub.2, said pivot point D.sub.2 being located at a distance A.sub.2D.sub.2 by the pivot point A.sub.2. The exoskeleton kinematic chain also comprises a first intermediate link pivotally connected to the first element at the pivot point B.sub.1 and integrally connected to the second end link at a junction point C.sub.2, a second intermediate link pivotally connected to the second element at the pivot point B.sub.2 and integrally connected to the first end link at a junction point C.sub.1. The first and the second end link are pivotally connected to each other at a pivot point M. Defining ==θ, for any value of θ, the projections of the pivot points A.sub.1, B.sub.1, A.sub.2, B.sub.2 in a plane π, lay in a circumference K having center O and radius r=A.sub.1D.sub.1=A.sub.2D.sub.2=D.sub.1B.sub.2=MB.sub.2=D.sub.2B.sub.1=MB.sub.1, in such a way that decreasing the value of θ the first and the second element rotate with respect to each other about an axis z orthogonal to the plane π and passing through the center O in the direction for which the point A.sub.1 is overlapped to the point B.sub.2.

Claims

1. An exoskeleton kinematic chain (100) arranged to pivotally connect a first element (101) to a second element (102), the first element (101) comprising pivot points A.sub.1 and B.sub.1 located at a distance A.sub.1B.sub.1, the second element (102) comprising pivot points A.sub.2 and B.sub.2 located at a distance A.sub.2B.sub.2, the exoskeleton kinematic chain (100) comprising: a first external link (111) pivotally connected to the first element (101) at the pivot point A.sub.1; a first end link (121) pivotally connected to the first external link (111) at a pivot point D.sub.1, the pivot point D.sub.1 being located at a distance A.sub.1D.sub.1 from the pivot point A.sub.1, the first external link (111) and the first end link (121) creating an angle =θ and arranged to rotate with respect to each other about an axis x.sub.1 passing through the pivot point D.sub.1; a second external link (112) pivotally connected to the second element (102) at the pivot point A.sub.2; a second end link (122) pivotally connected to the second external link (112) at a pivot point D.sub.2, the pivot point D.sub.2 being located at a distance A.sub.2D.sub.2 from the pivot point A.sub.2, the second external link (112) and the second end link (122) creating an angle ==θ and arranged to rotate with respect to each other about an axis x.sub.2 parallel to the axis x.sub.1 and passing through the pivot point D.sub.2; the first and second end links (121, 122) being pivotally connected to each other at a pivot point M, the pivot point M being located at a distance MB.sub.1 from the pivot point B.sub.1, at a distance MB.sub.2 from the pivot point B.sub.2, at a distance MD.sub.1 from the pivot point D.sub.1 and at a distance MD.sub.2 from the pivot point D.sub.2, wherein MB.sub.1=A.sub.1D.sub.1, MD.sub.1=A.sub.1B.sub.1 and MB.sub.2=A.sub.2D.sub.2, MD.sub.2=A.sub.2B.sub.2, wherein for any value of θ, pivot points A.sub.1, B.sub.1, A.sub.2, B.sub.2 in a plane π, orthogonal to the axes x.sub.1 and x.sub.2, lay in a circumference K, belonging to the plane π, that has a center O and a radius r=A.sub.1D.sub.1=A.sub.2D.sub.2=D.sub.1B.sub.2=MB.sub.2=D.sub.2B.sub.1=MB.sub.1, and in that the first element (101) and the second element (102) are each arc-shaped with the same radius rand the same center O, in such a way that decreasing the value of θ the first and second elements (101, 102) rotate concentrically to the circumference K and overlap with respect to each other about an axis z orthogonal to the plane π and passing through the center O in the direction for which the point A.sub.1 is overlapped to the point B.sub.2 and the point B.sub.1 is overlapped to the point A.sub.2.

2. The exoskeleton kinematic chain (100) of claim 1, further comprising: a first intermediate link (131) pivotally connected to the first element (101) at the pivot point B.sub.1 and integrally connected to the second end link (122) at a second junction point C.sub.2.

3. The exoskeleton kinematic chain (100) of claim 2, further comprising: a second intermediate link (132) pivotally connected to the second element (102) at the pivot point B.sub.2 and integrally connected to the first end link (121) at a first junction point C.sub.1.

4. The exoskeleton kinematic chain (100) of claim 3, wherein the first and second external links (111, 112) are arc-shaped, and the first and second end links (121, 122), and the first and second intermediate links (131, 132) are linearly shaped.

5. The exoskeleton kinematic chain (100) of claim 1, further comprising an actuating device which is adapted to adjust the value of the angle θ, the actuating device comprising at least one motor.

6. An exoskeleton structure for rehabilitation of an articulation of a user's limb, the structure comprising: a first element (101) and a second element (102) arranged to engage with a user's limb at a longitudinal segment having a longitudinal axis; a cylindrical joint (100′) arranged to cause a relative rotation between the first and second elements (101, 102) substantially about the longitudinal axis; wherein the cylindrical joint (100′) comprises an exoskeleton kinematic chain (100); wherein the exoskeleton kinematic chain is arranged to pivotally connect the first element (101) to the second element (102), the first element (101) comprising pivot points A.sub.1 and B.sub.1 located at a distance A.sub.1B.sub.1, the second element (102) comprising pivot points A.sub.2 and B.sub.2 located at a distance A.sub.2B.sub.2, the exoskeleton kinematic chain (100) comprising: a first external link (111) pivotally connected to the first element (101) at the pivot point A.sub.1; a first end link (121) pivotally connected to the first external link (111) at a pivot point D.sub.1, the pivot point D.sub.1 being located at a distance A.sub.1D.sub.1 from the pivot point A.sub.1, the first external link (111) and the first end link (121) creating an angle =θ and arranged to rotate with respect to each other about an axis x.sub.1 passing through the pivot point D.sub.1; a second external link (112) pivotally connected to the second element (102) at the pivot point A.sub.2; a second end link (122) pivotally connected to the second external link (112) at a pivot point D.sub.2, the pivot point D.sub.2 being located at a distance A.sub.2D.sub.2 from the pivot point A.sub.2, the second external link (112) and the second end link (122) creating an angle ==θ and arranged to rotate with respect to each other about an axis x.sub.2 parallel to the axis x.sub.1 and passing through the pivot point D.sub.2; the first and second end links (121, 122) being pivotally connected to each other at a pivot point M, the pivot point M being located at a distance MB.sub.1 from the pivot point B.sub.1, at a distance MB.sub.2 from the pivot point B.sub.2, at a distance MD.sub.1 from the pivot point D.sub.1 and at a distance MD.sub.2 from the pivot point D.sub.2, wherein MB.sub.1=A.sub.1D.sub.1, MD.sub.1=A.sub.1B.sub.1 and MB.sub.2=A.sub.2D.sub.2, MD.sub.2=A.sub.2B.sub.2, wherein for any value of θ, the projections of the pivot points A.sub.1, B.sub.1, A.sub.2, B.sub.2 in a plane π, orthogonal to the axes x.sub.1 and x.sub.2, lay in a circumference K, belonging to the plane π, that has a center O and a radius r=A.sub.1D.sub.1=A.sub.2D.sub.2=D.sub.1B.sub.2=MB.sub.2=D.sub.2B.sub.1=MB.sub.1, and in that the first element (101) and the second element (102) are each arc-shaped with the same radius r and the same center O, in such a way that decreasing the value of θ the first and second elements (101, 102) rotate concentrically to the circumference K and overlap with respect to each other about an axis z orthogonal to the plane π and passing through the center O in the direction for which the point A.sub.1 is overlapped to the point B.sub.2 and the point B.sub.1 is overlapped to the point A.sub.2.

7. The exoskeleton structure of claim 6, wherein the exoskeleton kinematic chain (100) further comprises: a first intermediate link (131) pivotally connected to the first element (101) at the pivot point B.sub.1 and integrally connected to the second end link (122) at a second junction point C.sub.2.

8. The exoskeleton structure of claim 7, wherein the exoskeleton kinematic chain (100) further comprises: a second intermediate link (132) pivotally connected to the second element (102) at the pivot point B.sub.2 and integrally connected to the first end link (121) at a first junction point C.sub.1.

9. The exoskeleton structure of claim 8, wherein the first and second external links (111, 112) are arc-shaped, and the first and second end links (121, 122), and the first and second intermediate links (131, 132) are linearly shaped.

10. The exoskeleton structure of claim 6, further comprising an actuating device which is adapted to adjust the value of the angle θ, the actuating device comprising at least one motor.

11. The exoskeleton structure, according to claim 6, wherein the first and second elements (101, 102) are adapted to engage with user's arm and wherein the cylindrical joint (100′) is configured to cause a relative rotation between the first and second elements (101, 102) which is adapted to be substantially about the axis of the user's humerus, and where an exoskeleton device configured for the user's shoulder (200) is also provided comprising: a first flange (210) pivotally engaged with the user's torso at an abdo-adduction axis x orthogonal to the first flange (210); a second flange (220) integral and substantially orthogonal to the first flange (210), the second flange (220) being pivotally engaged with the second element (102) at a flexion/extension axis y orthogonal to the abdo-adduction axis x.

12. The exoskeleton structure, according to claim 11, wherein the first flange (210) is configured to be pivotally connected to the user's torso by a connection link (230) having a first end (231), connected to the first flange (210) at the abdo-adduction axis x by a rotational joint, and a second end (232), connected by a spherical joint to an engagement belt arranged to engage with the user's torso.

13. The exoskeleton structure, according to claim 11, wherein the exoskeleton device for a user's shoulder comprises furthermore: a first motor (240) having rotation axis parallel to the abdo-adduction axis x, the first motor (240) arranged to cause the rotation of the first flange (210) about the abdo-adduction axis x; a second motor (250) having rotation axis parallel to the abdo-adduction axis x, the second motor (250) arranged to cause a relative rotation between the second flange (220) and the second element (102), the rotation being transmitted by means of cables and pulleys.

14. The exoskeleton structure, according to claim 6, wherein the first and second elements (101, 102) are adapted to engage with user's arm and wherein the cylindrical joint (100′) is configured to cause a relative rotation between the first and second elements (101, 102) substantially about the axis of the user's humerus; and where an exoskeleton device for elbow (300) is also provided comprising: a support element (310) constrained to the first element (101) through adjustment means; a third element (320) arranged to engage with a user's limb at the forearm, the third element (320) being pivotally constrained to the support element (310).

15. The exoskeleton structure, according to claim 14, wherein the adjustment means comprises: a slide (311) arranged to axially adjust the relative position between the support element (310) and the first element (101); a pivotal constraint (312) arranged to rotationally adjust the relative position between the support element (310) and the first element (101).

16. The exoskeleton structure, according to claim 14, wherein the support element (310) comprises a motor (315) arranged to cause a rotation of the third element (320) with respect to the support element (310), the rotation being transmitted by a couple of mating gears with orthogonal axes.

17. The exoskeleton structure, according to claim 11, further comprising a support base (400) comprising: a platform capable of fastening to the ground (410) comprising a support column (411); a parallelogram linkage (420) comprising two parallel rods (421, 422) pivotally connected to the support column (411) and to an end element (425), the end element (425) being pivotally connected to the first flange (210) at the abdo-adduction axis x.

18. The exoskeleton structure, according to claim 6, wherein the first and second external links (111, 112) are arc-shaped, and the first and second end links (121, 122), and the first and second intermediate links (131, 132) are linearly shaped.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further characteristic and/or advantages of the present invention are more bright with the following description of an exemplary embodiment thereof, exemplifying but not limitative, with reference to the attached drawings in which:

(2) FIG. 1 shows the geometric scheme of a kinematic chain, according to the present invention, for the relative rotation between two coaxial cylindrical elements, by means of remote centers actuation;

(3) FIG. 2 shows, in plan view, a schematic representation of a cylindrical joint that uses the kinematic chain of FIG. 1;

(4) FIG. 3 shows, in perspective, the schematic representation of the joint of FIG. 1;

(5) FIG. 4 shows, in plan view, a possible exemplary embodiment of a cylindrical joint that uses the kinematic chain of FIG. 1;

(6) FIGS. 5A and 5B show, from different perspectives, the cylindrical joint of FIG. 4;

(7) FIG. 6 shows, in plan view, a possible exemplary embodiment of an exoskeleton structure for rehabilitation of an articulation of a user's limb, which integrates the kinematic chain according to the present invention;

(8) FIGS. 7A and 7B show, from different perspectives, the exoskeleton structure of FIG. 6;

(9) FIG. 8 shows a perspective view of an exemplary embodiment alternative to the exoskeleton structure of FIG. 6, wherein exoskeleton devices for shoulder and for elbow are also comprised;

(10) FIG. 9 shows a perspective view of an alternative exemplary embodiment of the exoskeleton structure of FIG. 6, where a movable support base is also comprised.

DESCRIPTION OF A PREFERRED EXEMPLARY EMBODIMENT

(11) In FIG. 1 a geometric scheme is shown of the kinematic chain 100, according to the present invention, for the relative rotation between two elements 101,102 by means of a remote centers system.

(12) In particular, the first element 101 comprises two pivot points A.sub.1 and B.sub.1 located at a distance A.sub.1B.sub.1, whereas the second element 102 comprises two pivot points A.sub.2 and B.sub.2 located at a distance A.sub.2B.sub.2. Two external links 111,112 are then provided hinged to the elements 101,102, respectively, at the pivot points A.sub.1 and A.sub.2. Two end links 121,122 are then hinged to the external links 111,112, respectively, at pivot points D.sub.1 and D.sub.1, and they are also hinged to each other at a pivot point M. Finally, two intermediate links 131,132 are hinged to the elements 101,102, respectively, at the pivot points B.sub.1 and B.sub.2, and they are also integrally connected to the end links 121,122, respectively, at points of fixed joint C.sub.1 and C.sub.2.

(13) By appropriately sizing the distance between the various above mentioned points in such a way that you have MB.sub.1=A.sub.1D.sub.1, MD.sub.1=A.sub.1B.sub.1, MB.sub.2=A.sub.2D.sub.2, MD.sub.2=A.sub.2B.sub.2, the kinematic chain 100 is the combination of two virtual parallelogram linkages, wherein, in particular, points A.sub.1, B.sub.1, M, D.sub.1 shape the vertices of a first parallelogram linkage, whereas points A.sub.2, B.sub.2, M, D.sub.2 shape the vertices of a second parallelogram linkage.

(14) Defining =θ the angle shaped by the links 111,121, using easy geometric formulas it is possible to show that it is equal to angle shaped by the links 112,122 =θ and that a variation any of value of θ keeps constantly points A.sub.1, B.sub.1, A.sub.2, B.sub.2 on a circumference K, belonging to the plane π, and having center O and radius r=A.sub.1D.sub.1=A.sub.2D.sub.2=D.sub.1B.sub.2=MB.sub.2=D.sub.2B.sub.1=MB.sub.1.

(15) In particular, being the points A.sub.1 and B.sub.1 integral to the element 101 and the points A.sub.2 and B.sub.2 integral to the element 102, it is possible to show that decreasing the value of θ the elements 101,102 rotate with respect to each other about the center O in the direction for which the point A.sub.1 is overlapped to the point B.sub.2 and the point B.sub.1 is overlapped to the point A.sub.2 on the circumference K.

(16) In particular, the first and the second element 101,102 have curved shape with radius of curvature r and center of curvature O, in such a way that changing θ the first and the second element 101,102 rotate with respect to each other about an axis perpendicular to the sheet and passing through the center of curvature O.

(17) In the FIGS. 2, 3, 4, 5A and 5B, respectively, a schematic application and a realistic application of the kinematic chain 100 are shown. In particular, in such exemplary embodiments the elements 101 and 102 are located on parallel planes in such a way that the projections orthogonal to the sheet of the points A.sub.1, B.sub.1, A.sub.2, B.sub.2 lay on the same circumference K having center O and radius r. In this case, therefore, the kinematic chain 100 carries out a cylindrical joint that allows the rotation between the two elements 101 and 102 about an axis passing through the centers of curvature of the two elements 101 and 102.

(18) In particular, in FIG. 4 a rotation of the element 102 is shown with respect to the element 101 that remains fixed. The dashed lines show the position of the kinematic chain 100 in consequence of a change of the angle θ. It is possible to see the sliding the points A.sub.2, B.sub.2, C.sub.1, D.sub.1, C.sub.2, D.sub.2, M in the corresponding points A′.sub.2, B′.sub.2, C′.sub.1, D′.sub.1, C′.sub.2, D′.sub.2, M′.

(19) The main advantage of the kinematic chain 100 with respect to cylindrical joints of the prior art resides in that it is possible to actuate the relative rotation between the elements 101 and 102 bringing in rotation any of the links 111,121,131,112,122,132 with respect to a link hinged to it, changing proportionally all the angles set between links hinged to each other.

(20) It is therefore possible, to obtain a cylindrical joint that brings in rotation to each other coplanar elements or elements arranged on parallel planes without needing the access to the axis with respect to which the rotation is carried out, but simply making a rotation of the kinematic chain about any axis orthogonal to the plane containing the circumference K and passing through one of the remote centers consisting of the above mentioned pivot points.

(21) In the FIGS. 6, 7A and 7B an exoskeleton structure for rehabilitation of an articulation of a user's limb is shown that uses a cylindrical joint 100′ comprising the kinematic chain 100 above described.

(22) In particular, the two engagement elements 101′ and 102′ are adapted to engage with a user's limb at a longitudinal segment, such as an arm, a forearm, a thigh or a leg. Advantageously, the engagement elements 101′ and 102′ are adapted to engage at two portions located at different heights along the longitudinal axis of the anatomical segment.

(23) Furthermore, the exoskeleton structure comprises a motor 150′ configured to actuate the cylindrical joint 100′, in order to produce a relative rotation between the engagement elements 101′ and 102′, thus obtaining a torsion of the anatomical segment about its own axis.

(24) More in detail, in an exemplary embodiment of FIGS. 6, 7A and 7B the engagement elements 101′ and 102′ can be engaged to user's arm at different heights, in such a way that the motor 150′ can actuate a torsion of the arm about an axis substantially passing through the user's humerus.

(25) The use of the kinematic chain 100 in the exoskeleton structure above described makes it possible to carry out the torsion of the arm by a motor located in remote, without needing creeping elements or engagement elements that completely envelop the user's arm resulting uncomfortable and heavy, besides being difficult to wear and to maintain.

(26) In FIG. 8 the exoskeleton structure of previous figures is shown, wherein an exoskeleton device for shoulder 200 and an exoskeleton device for elbow 300 are also provided.

(27) In particular, the exoskeleton device for shoulder 200 comprises a first flange 210 pivotally engaged with the shoulder of a user at a abdo-adduction axis x. In particular, a connection link 230 is provided having a first end 231, connected to the first flange 210 at the abdo-adduction axis x by a rotational joint, and a second end 232, connected by a spherical joint to an engagement belt arranged to engage with the user's torso. The exoskeleton device for shoulder 200 comprises then a second flange 220, integral and substantially orthogonal to the first flange 210, and pivotally engaged with the second engagement element 102′ at an axis of flexion-extension y orthogonal to the abdo-adduction axis x.

(28) The exoskeleton device for shoulder 200 also comprises a first motor 240 having rotation axis coincident with the abdo-adduction axis x, in order to cause the rotation of the first flange 210 about its abdo-adduction axis x. A second motor 250 is further provided that has rotation axis parallel to the abdo-adduction axis x, and arranged to cause a relative rotation between the second flange 220 and the second engagement element 102′. In particular, the rotation is transmitted by means of cables, chains, belts or other flexible elements, meshing on pulleys or sprockets, which transmit the rotation between two orthogonal axes, as shown in FIG. 6. The advantage of placing the two motors 240,250 both on the first flange 210 resides in reducing the moment of inertia during the rotation about its abdo-adduction axis x.

(29) Still with reference to FIG. 8, the exoskeleton device for elbow 300 comprises a support element 310 constrained to the first engagement element 101′ through adjustment means. The exoskeleton device for elbow 300 also comprises a third engagement element 320, pivotally constrained to the support element 310, and arranged to engage with a user's limb at the forearm.

(30) In particular, the adjustment means comprises a slide 311 and a pivotal constraint 312 arranged to allow to adjust, respectively, axially and rotationally the relative position between the support element 310 and the engagement element 101′. This way, it is possible to adapt the exoskeleton structure to different anthropometric sizes of a user.

(31) Advantageously, the support element 310 comprises a motor 315 arranged to cause a rotation of said third engagement element 320 with respect to said support element 310, in particular said rotation being transmitted by a couple of mating gears with orthogonal axes, as conical wheels, screw/nut screw or helical gears with not incidental orthogonal axes.

(32) In FIG. 9 the exoskeleton structure of previous figures is shown, where a support base 400 is also provided comprising a platform of fastening to ground 410 equipped with a support column 411. The support base also comprises a parallelogram linkage 420 consisting of two parallel rods 421,422 hinged to the support column 411 and to an end element 425 pivotally connected to the first flange 210 at the abdo-adduction axis x.

(33) In particular, the parallelogram linkage 420 can also rotate about vertical axes both with respect to the support column, both with respect to the first flange.

(34) Advantageously, the parallel rods are connected to a counterweight that counterbalances the weight of the exoskeleton structure pivoting on the pivot points between the parallel rods and the support column.

(35) In particular, the platform of fastening has wheels that allow the handling and the and repositioning of the support base 400, in order to ensure a maximum freedom of movement to the user.

(36) The foregoing description some exemplary specific embodiments will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt in various applications the specific exemplary embodiments without further research and without parting from the invention, and, accordingly, it is meant that such adaptations and modifications will have to be considered as equivalent to the specific embodiments. The means and the materials to realise the different functions described herein could have a different nature without, for this reason, departing from the field of the invention. it is to be understood that the phraseology or terminology that is employed herein is for the purpose of description and not of limitation.