SHOULDER-FRIENDLY EXOSKELETON STRUCTURE

FIELD OF THE INVENTION

An exoskeleton structure is disclosed.

STATE OF THE ART

Exercise-assist exoskeletons are mechanical structures that double the structure of the human skeleton and which improve the physical capacities of the human body.

There are different types of exoskeletons for assisting the effort which depend on the tasks to be performed by the user. Each type of exoskeleton makes it possible to limit or reduce the effort provided by the user when performing certain tasks.

For example, there are exoskeleton structures making it possible to assist a user when he performs tasks involving movements of a shoulder, in particular for lifting and handling loads.

However, these structures generally do not allow to adapt to all the movements of the shoulder. For example, these structures may allow movement of flexion and extension of the arm, but not allow movement of abduction and adduction of the arm.

However, the shoulder complex is a complex articular system with six cumulative degrees of freedom (combining the movements of the scapula and those of the shoulder as such).

Other structures have also been proposed making it possible to better reproduce the movements of the shoulder. However, these structures are generally very bulky, which hinders the mobility of the user.

Furthermore, the integration of several actuators in these structures leads to an increase in the mass and in the energy consumption of the structure.

Finally, it should be noted that during certain sequences of movements of the shoulder, certain structures of the exoskeleton can go through configurations called “singular points”, which causes the blocking of the structure. Blocking of the exoskeletal structure is the loss of a degree of freedom that occurs in configurations in which two of the structure's rotational axes are aligned with each other. These blocking situations require at least the reverse of the sequence of movements that resulted in the singularity to free the user from his movements, and can even damage the structure of the exoskeleton and create discomfort for the user.

SUMMARY OF THE INVENTION

An object of the invention is to provide an exoskeleton structure which provides greater freedom of movement for the shoulder while being compact.

This aim is achieved in the context of the present invention by virtue of an exoskeleton structure comprising:

- a set of backs intended to be fixed on the back of a user,

- a set of arms intended to be fixed to an arm of the user,

a shoulder linkage device connecting the back assembly to the arm assembly, the shoulder linkage device comprising a first linkage piece, a first pivot connecting the first linkage piece to the back assembly by allowing rotation of the first connecting piece with respect to the back assembly about a first axis of rotation parallel to an internal / external axis of rotation of the user's shoulder, a second connecting piece, a second pivot connecting the first connecting part to the second connecting part by allowing rotation of the second connecting part relative to the first connecting part about a second axis of rotation orthogonal to the first axis of rotation, a third pivot connecting the second connecting piece to thearm assembly by allowing rotation of the arm assembly relative to the second connecting piece about a third axis of rotation orthogonal to the second axis of rotation,

wherein the second pivot is arranged so that the second axis of rotation forms a non-zero angle with an abduction / adduction axis of the user's shoulder and a non-zero angle with a flexion / extension axis of the user's shoulder when the user is standing with the arms relaxed to the side of the body.

In such a structure, the second axis of rotation forms a non-zero angle both with an abduction / adduction axis of the user's shoulder and with a flexion / extension axis of the user's shoulder. . It is therefore possible to design a structure in which a single actuator allows both to assist the user during an abduction / adduction movement of the shoulder and during a flexion / extension movement of the shoulder. shoulder, which reduces the mass of the structure and its energy consumption.

In addition, with this configuration of the second axis of rotation, the user can for example successively carry out movements of flexion of the shoulder, then of adduction of the scapula, then a movement of extension of the shoulder without the connecting device does not pass through a singular point, which avoids creating blocking situations.

The proposed structure may also have the following characteristics:

- the third pivot is arranged so that the third axis of rotation is orthogonal to the first axis of rotation, when the user is standing with his arms relaxed alongside the body,

- The structure comprises an actuator including a stator and a rotor mounted to rotate relative to the stator, one of the stator and the rotor being mounted fixed on the first connecting piece, and the other of the stator and the rotor being mounted fixed on the second connecting part, the actuator being able to generate a torque to drive the second connecting part in rotation with respect to the third connecting part,

- The arm assembly comprises a clean arm piece to come to bear against the user's arm to drive the user's arm in rotation relative to the user's back, by means of the actuator,

- the arm assembly comprises a first arm piece suitable for surrounding the user's arm to fix the first arm piece to the user's arm, and a second arm piece mounted to rotate relative to the first piece of arm so as to allow rotation of the user's arm relative to the second arm piece, while being able to press the first arm piece against the user's arm to drive the arm in rotation by the actuator bias,

- The arm assembly comprises a third connecting piece and a fourth pivot, the third connecting piece having a first end connected to the shoulder connecting device by means of the third pivot, and a second end connected to the arm through the fourth pivot,

- the fourth pivot allows rotation of the arm part relative to the third connecting part about a fourth axis of rotation parallel to the third axis of rotation,

- the third connecting piece includes two pieces mounted to slide relative to each other by means of a slide, the sliding of the pieces relative to each other allowing a shortening or lengthening of the third connecting piece during rotation of the arm assembly relative to the back assembly,

- the arm assembly includes a forearm piece suitable for surrounding the user's forearm to secure the arm assembly to the user's arm, while allowing rotation of the arm of the user. user inside the forearm piece during an internal-external rotational movement of the shoulder,

- the arm assembly comprises a fifth pivot connecting the forearm piece to the arm piece and allowing rotation of the forearm piece relative to the arm piece about a fifth axis of rotation during a rotation of the user's elbow,

- the connecting device comprises a four-bar mechanism connecting the back assembly to the first pivot, the four-bar mechanism comprising four bars, and four articulations connecting the bars to one another forming a deformable parallelogram,

- each articulation of the four-bar mechanism has an axis of rotation, each axis of rotation extending parallel to a direction orthogonal to a frontal plane of the user,

- The connecting device further comprises an elastic return member suitable for exerting a return force tending to oppose a deformation of the parallelogram.

PRESENTATION OF THE DRAWINGS

Other characteristics and advantages will emerge from the following description, which is purely illustrative and non-limiting, and should be read in conjunction with the appended figures, among which:

- Figure 1 schematically shows an exoskeleton structure according to a possible embodiment of the invention, in a configuration in which the user is standing with his arms relaxed alongside the body,

- Figure 2 shows schematically the structure of the exoskeleton, in a configuration in which the user is standing, the arm extended forward, after having executed a flexion movement of the shoulder,

- Figure 3 shows schematically the structure of the exoskeleton, in a configuration in which the user is standing, the arm extended to the side, after having successively executed a flexion movement of the shoulder then a movement of shoulder abduction,

- Figure 4 schematically shows the structure of the exoskeleton during a flexion movement of the user's elbow,

- Figure 5 schematically shows a variant of the exoskeleton structure of Figures 1 to 4.

DETAILED DESCRIPTION OF AN EMBODIMENT

FIG. 1 illustrates a frontal plane F, a sagittal plane S and a transverse plane T of the user. In a known manner, the sagittal plane S is defined as a plane parallel to the median plane which separates the left half of the

right half of the user's body. The frontal plane F or coronal plane is defined as a plane perpendicular to the median plane and which separates the body into an anterior or ventral part and a posterior or dorsal part. The transverse plane T or transverse plane is defined as a plane perpendicular to the median plane and which separates the body into an upper part (on the side of the head) and a lower part (on the side of the feet).

In Figure 1, the user is standing with his arms relaxed along the body. The user is equipped with an exoskeleton structure 1 making it possible to assist the movements of his shoulder.

The exoskeleton structure 1 includes a back assembly 2 which, in normal use, is attached to a user's back, an arm assembly 3 attached to an arm of the user, and a shoulder linkage device 4 connecting back assembly 2 to arm assembly 3.

The back assembly 2 comprises for example a belt 5 surrounding the lower trunk of the user and a back piece 6 fixed to the lumbar belt 5 and extending along the user's spine.

The arm assembly 3 comprises an arm piece 7 suitable for resting against the user's arm and a forearm piece 8 suitable for surrounding the user's forearm in order to secure the assembly arm 3 to the user's arm.

The shoulder connecting device 4 comprises a four-bar mechanism 9, a first pivot 10, a first connecting piece 1 1, a second pivot 12, a second connecting piece 13, a third pivot 14 and a third piece of bond 15.

The four-bar mechanism 9 connects the back assembly 2 to the first pivot 10. The four-bar mechanism 9 comprises four bars 16, and four articulations 17 connecting the bars 16 to each other forming a deformable parallelogram. Each articulation 17 of the four-bar mechanism 9 has an axis of rotation, each axis of rotation extending parallel to a direction orthogonal to the frontal plane F of the user, in normal use.

The shoulder connection device 9 further comprises an elastic return member 28 suitable for applying to the four-bar mechanism 9 a return force tending to oppose the deformation of the parallelogram caused by the weight of the connection device d. 'shoulder 4 and the arm assembly 3. More specifically, the elastic return member 28 comprises a spring extending between two joints located at two opposite angles of the parallelogram. In the example illustrated in Figure 1, the spring is a tension spring connecting one of the articulation 28 located in an upper angle, closest to the sagittal plane, to another of the articulations 28 located in a lower angle, the more distant from the sagittal plane. Thus, the return force exerted by the tension spring tends to pull the arm assembly 3 upward relative to the back assembly 2, so as to compensate for the weight exerted by the shoulder linkage device and by the arm assembly. The stiffness of the elastic return member 28 can be adjusted as a function of the weight to be compensated.

The first pivot 10 connects the first connecting piece to the four-bar mechanism 9. The first pivot 10 allows rotation of the first connecting piece 1 1 relative to the back assembly 2 about a first axis of rotation X1 parallel to an internal / external rotation axis of the user's shoulder.

The second pivot 12 connects the first connecting piece 1 1 to the second connecting piece 13. The second pivot 12 allows rotation of the second connecting piece 13 relative to the first connecting piece 1 1 about a second axis of rotation X2 orthogonal to the first axis of rotation X1.

The second pivot 12 is arranged so that the second axis of rotation X2 forms a non-zero angle with an abduction / adduction axis of the user's shoulder and a non-zero angle with a flexion / extension axis of the user's shoulder when the user is standing with the arms relaxed to the side of the body as shown in Figure 1.

The third pivot 14 connects the second connecting piece 13 to the third connecting piece 15. The third pivot 14 allows rotation of the arm assembly 3 relative to the second connecting piece 13 around

a third axis of rotation X3 orthogonal to the second axis of rotation X2.

The third pivot 14 is arranged so that the third axis of rotation X3 is orthogonal to the first axis of rotation X1 and to the second axis of rotation X2, when the user is standing with his arms relaxed alongside the body. In addition, the third axis of rotation X3 forms a non-zero angle with the abduction / adduction axis of the user's shoulder and a non-zero angle with the axis of flexion / extension of the shoulder of the user. the user when the user is standing with the arms relaxed to the side of the body.

Thanks to the first pivot 10, the second pivot 12 and the third pivot 14, the connecting device 4 allows rotation of the arm assembly 3 relative to the back assembly 8 according to three degrees of freedom.

The exoskeleton structure 1 also comprises an actuator 18 including a stator 19 and a rotor 20 rotatably mounted relative to the stator 19. The stator 19 is for example mounted fixedly on the first connecting piece 11 and the rotor 20 is for example fixedly mounted on the second connecting part 13. The actuator 18 is able to generate a torque for rotating the second connecting part 13 relative to the first connecting part 11. The actuator may for example comprise an electric motor of the brushless type or a geared motor.

The actuator 18 can be activated to assist the arm of the user during an abduction / adduction and / or flexion / extension movement of the user's shoulder, i.e. to provide an additional effort which is added to the effort produced by the user to produce the movement of the shoulder.

The arm assembly 3 further includes a fourth pivot 21. The fourth pivot 21 connects the third connecting piece 15 to the arm piece 7. The fourth pivot 21 allows rotation of the arm piece 7 relative to the third connecting piece 15 about a fourth axis of rotation X4 parallel. to the third axis of rotation X3.

The third connecting piece 15 has a first end connected to the second connecting piece 13 via the third pivot 14, and a second end connected to the arm part 7 via the fourth pivot 21.

Furthermore, the third connecting part 15 comprises two parts 22 and 23 mounted to slide with respect to one another by means of a slide. The axial sliding of the parts 22 and 23 relative to each other allows a shortening or an elongation of the third connecting piece 15 during a rotation of the arm assembly 3 relative to the back assembly 2, which makes it possible to accommodate a misalignment of the axes of rotation X1, X2 and X3 with the real center of rotation of the user's shoulder.

Furthermore, the part 23 is mounted to rotate relative to the part 22 about the sliding axis of the part 23 relative to the part 22.

Finally, the forearm part 8 allows rotation of the shoulder inside the forearm part 8 during an internal-external rotational movement of the shoulder.

FIG. 2 schematically represents the structure of the exoskeleton 1, when the user is standing, the arm extended forwards, after having executed a flexion movement of the shoulder.

The flexion movement of the shoulder causes both a rotation of the second connecting piece 13 relative to the first connecting piece 1 1 about the second axis of rotation X1 and a rotation of the third connecting piece 15 relative to the second connecting piece 13 around the third axis of rotation X3.

The bending movement can be assisted by the activation of the actuator 18. When it is activated, the actuator 18 indeed generates a torque tending to drive the second connecting piece 13 in rotation relative to the first piece of link 1 1, and therefore to support the arm piece 7 on the user's arm to assist the arm during the flexion movement of the shoulder. The arm piece 7 bears against the user's arm to drive the user's arm in flexion or extension with respect to the user's scapula, through the actuator 18.

As illustrated in Figure 2, once the user's arm extends horizontally forward, the first axis of rotation X1 is parallel to the third axis of rotation X3.

FIG. 3 schematically represents the structure of the exoskeleton, when the user is standing, the arm extended to the side, after having successively executed a movement of flexion of the shoulder and an abduction movement of the shoulder .

The abduction movement of the shoulder causes both a rotation of the second connecting piece 13 relative to the first connecting piece 1 1 about the first axis of rotation X1 and a rotation of the third connecting piece 15 by relative to the second connecting piece 13 about the third axis of rotation X3.

The abduction movement can be assisted by the activation of the actuator 18. When it is activated, the actuator 18 in fact generates a torque tending to drive the second connecting part 13 in rotation relative to the first part. link 1 1, and therefore to support the arm piece 7 on the user's arm to drive the arm in rotation. The arm piece 7 bears against the user's arm to drive the user's arm in abduction or adduction with respect to the user's scapula, by means of the actuator 18.

Thus, the actuator 18 serves both to assist the user during a flexion / extension movement of the shoulder and during an abduction / adduction movement of the shoulder.

Further, as shown in Figure 3, after the user's arm extends horizontally to the side, the first axis of rotation X1, the second axis of rotation X2, and the third axis of rotation X3 are not aligned two to two. The connecting device 4 avoids going through singular points which could cause the blockage of the exoskeleton structure 1. In addition, the efficiency of the actuator is retained.

As illustrated in Figure 4, the arm assembly 3 also includes a fifth pivot 27 connecting the forearm piece 8 to the arm piece 7. The fifth pivot allows rotation of the forearm piece 8. relative to the arm piece 7 about a fifth axis of rotation X5

when the user's elbow rotates. More precisely, the fifth pivot 27 allows rotation of the forearm piece 8 relative to the arm piece 7 about a fifth axis of rotation X5 during a flexion or extension movement of the elbow. the user.

The exoskeleton structure may further comprise a second actuator 24 including a stator 25 and a rotor 26 rotatably mounted relative to the stator 25. The stator 25 is for example fixedly mounted on the arm piece 7 and the rotor 26 is for example fixedly mounted on the forearm part 8. The actuator 24 is able to generate a torque to drive the forearm part 8 in rotation relative to the arm part 7. The actuator 24 may comprise by example an electric motor of the brushless type or a geared motor.

The actuator 24 can be activated to assist the user's arm during a flexion / extension movement of the user's elbow, that is to say to provide an additional force which is added to the effort produced by the user to produce the movement of the elbow.

Figure 5 illustrates a variant of the exoskeleton structure of Figures 1 to 4. The exoskeleton structure 1 shown in Figure 5 is identical to the exoskeleton structure shown in Figures 1 to 4, except for the arm assembly 3.

In this variant, the arm assembly 3 comprises a first arm piece 31 suitable for surrounding the user's arm to secure the arm assembly 3 to the user's arm, and a second arm piece 32 mounted to rotate relative to the first arm piece 32. More precisely, in the example illustrated in FIG. 5, the second arm piece 32 surrounds the first arm piece 31, while allowing rotation of the first arm piece 31 ( and therefore a rotation of the user's arm) relative to the second arm piece 32.

The third pivot 14 connects the third connecting piece 15 to the arm piece 7 through the fourth pivot 21.

In the example illustrated in Figure 5, the arm assembly 3 does not include a forearm piece 8. However, the arm assembly could also include a forearm piece 8 connected to the second.

arm piece 32 through a fifth pivot 27, as shown in Figures 1 to 4.

CLAIMS

1. Exoskeleton structure (1) comprising:

- a back assembly (2) intended to be fixed on the back of a user, - a set of arms (3) intended to be fixed to an arm of the user,

- A shoulder connecting device (4) connecting the back assembly (2) to the arm assembly (3), the shoulder connecting device (4) comprising a first connecting piece (1 1) , a first pivot (10) connecting the first connecting piece (1 1) to the back assembly (2) by allowing rotation of the first connecting piece (1 1) relative to the back assembly (2) ) around a first axis of rotation (X1) parallel to an internal / external axis of rotation of the user's shoulder, a second connecting piece (13), a second pivot (12) connecting the first piece of connection (1 1) to the second connecting piece (13) by allowing rotation of the second connecting piece (13) relative to the first connecting piece (1 1) arounda second axis of rotation (X2) orthogonal to the first axis of rotation (X1), a third pivot (14) connecting the second connecting piece (13) to the arm assembly (3) allowing rotation of the assembly of arm (3) relative to the second connecting piece (13) around a third axis of rotation (X3) orthogonal to the second axis of rotation (X2),

wherein the second pivot (12) is arranged so that the second axis of rotation (X2) forms a non-zero angle with an abduction / adduction axis of the user's shoulder and a non-zero angle with a axis of flexion / extension of the user's shoulder when the user is standing with the arms relaxed at the side of the body.

2. Structure according to claim 1, wherein the third pivot (14) is arranged so that the third axis of rotation (X3) is orthogonal to the first axis of rotation (X1), when the user is standing, the arms relaxed along the body.

3. Structure according to one of claims 1 and 2, comprising an actuator (18) including a stator (19) and a rotor (20) rotatably mounted by

relative to the stator (19), one of the stator and the rotor being fixedly mounted on the first connecting part (1 1), and the other of the stator and the rotor being fixedly mounted on the second connecting part (13) , the actuator (18) being able to generate a torque for rotating the second connecting part (13) relative to the third connecting part (1 1).

4. Structure according to claim 3, wherein the arm assembly (3) comprises an arm piece (7) adapted to bear against the user's arm to drive the arm in rotation through the actuator (18).

5. Structure according to claim 3, wherein the arm assembly (3) comprises a first arm piece (31) adapted to surround the user's arm to fix the first arm piece (31) to the arm of the user. 'user, and a second arm piece (32) rotatably mounted relative to the first arm piece (31) so as to allow rotation of the user's arm relative to the second arm piece (32), all by being able to bring the first arm piece (31) to bear against the user's arm to drive the arm in rotation by means of the actuator (18).

6. Structure according to one of claims 4 and 5, wherein the arm assembly (3) comprises a third connecting piece (15) and a fourth pivot (21), the third connecting piece (15) having a first end connected to the shoulder connection device (4) via the third pivot (14), and a second end connected to the or one of the arm piece (s) (7, 32) via of the fourth pivot (21).

7. Structure according to claim 6, wherein the fourth pivot (21) allows rotation of the part (s) of the arm (7, 31, 32) relative to the third connecting part (15) around. a fourth axis of rotation (X4) parallel to the third axis of rotation (X3).

8. Structure according to one of claims 6 and 7, wherein the third connecting piece (15) includes two parts (22, 23) slidably mounted one

relative to the other by means of a slideway, the sliding of the parts (22, 23) relative to each other allowing a shortening or an elongation of the third connecting part (15) during rotation of the arm assembly (3) relative to the back assembly (2).

9. Structure according to one of claims 1 to 8, wherein the arm assembly (3) comprises a forearm piece (8) adapted to surround the forearm of the user to fix the arm assembly (3) to the user's arm, while allowing rotation of the user's arm within the forearm piece (8) during an internal-external rotational movement of the shoulder.

10 Structure according to one of claims 4 to 8 in combination with claim 9, wherein the arm assembly (3) comprises a fifth pivot (27) connecting the forearm piece (8) to the arm (7) and allowing rotation of the forearm piece (8) relative to the arm piece (7) about a fifth axis of rotation (X5) during a rotation of the elbow of the user.

11. Structure according to one of claims 1 to 10, wherein the connecting device (4) comprises a four bar mechanism (9) connecting the back assembly (2) to the first pivot (10), the mechanism to four bars (9) comprising four bars (16), and four articulations (17) connecting the bars (16) to each other forming a deformable parallelogram.

12. Structure according to claim 11, wherein each articulation (17) of the four-bar mechanism (9) has an axis of rotation, each axis of rotation extending parallel to a direction orthogonal to a frontal plane of the user. .

13. Structure according to one of claims 1 1 and 12, wherein the connecting device (4) further comprises an elastic return member

(28) suitable for exerting a restoring force tending to oppose a deformation of the parallelogram.