Exoskeleton structure adapted to the shoulder

1. An exoskeleton structure comprising:

a back assembly intended to be attached to a back of a user;

an arm assembly intended to be attached to an arm of the user; and

a shoulder connection device connecting the back assembly to the arm assembly, the shoulder connection device comprising a first connection part, a first pivot connecting the first connection part to the back assembly while allowing rotation of the first connection part relative to the back assembly around a first axis of rotation parallel to an internal/external axis of rotation of a shoulder of the user, a second connection part, a second pivot connecting the first connection part to the second connection part while allowing rotation of the second connection part relative to the first connection part around a second axis of rotation orthogonal to the first axis of rotation, a third pivot connecting the second connection part to the arm assembly while allowing rotation of the arm assembly relative to the second connection part around 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 shoulder of the user and a non-zero angle with a flexion/extension axis of the shoulder of the user when the user is standing, arms relaxed along a body of the user.

2. The exoskeleton structure according to claim 1 , wherein 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, arms relaxed along the body of the user.

3. The exoskeleton structure according to claim 1 , comprising an actuator including a stator and a rotor mounted in rotation relative to the stator, one of the stator and the rotor being mounted fixed on the first connection part, and the other of the stator and the rotor being mounted fixed on the second connection part, the actuator being capable of generating a torque to drive in rotation the second connection part relative to the first connection part.

4. The exoskeleton structure according to claim 3 , wherein the arm assembly comprises an arm part capable of being supported against the arm of the user to drive the arm in rotation by means of the actuator.

5. The exoskeleton structure according to claim 3 , wherein the arm assembly comprises a first arm part capable of surrounding the arm of the user and adapted to attach the first arm part to the arm of the user, and a second arm part mounted in rotation relative to the first arm part so as to allow rotation of the arm of the user relative to the second arm part while still being capable of supporting the first arm part against the arm of the user to drive the arm of the user in rotation by means of the actuator.

6. The exoskeleton structure according to claim 4 , wherein the arm assembly comprises a third connection part and a fourth pivot, the third connection part having a first end connected to the shoulder connection device by means of the third pivot, and a second end connected to the arm part by means of the fourth pivot.

7. The exoskeleton structure according to claim 6 , wherein the fourth pivot allows rotation of the arm part relative to the third connection part around a fourth axis of rotation parallel to the third axis of rotation.

8. The exoskeleton structure according to claim 6 , wherein the third connection part includes two parts mounted sliding relative to one another by means of a runner, so as to allow shortening or lengthening of the third connection part during rotation of the arm assembly relative to the back assembly.

9. The exoskeleton structure according to claim 1 , wherein the arm assembly comprises a forearm part capable of surrounding a forearm of the user and adapted to attach the arm assembly to the arm of the user, while still allowing rotation of the arm of the user inside the forearm part during an internal-external rotation movement of the shoulder.

10. The exoskeleton structure according to claim 4 , wherein the arm assembly comprises a forearm part capable of surrounding a forearm of the user and adapted to attach the arm assembly to the arm of the user, while still allowing rotation of the arm of the user inside the forearm part during an internal-external rotation movement of the shoulder, and

wherein the arm assembly comprises a fifth pivot connecting the forearm part to the arm part and allowing rotation of the forearm part relative to the arm part around a fifth axis of rotation during rotation of an elbow of the user.

11. The exoskeleton structure according to claim 1 , wherein the shoulder connection device comprises a four-bar mechanism connecting the back assembly to the first pivot, the four-bar mechanism comprising four bars and four hinges connecting the four bars to one another by forming a deformable parallelogram.

12. The exoskeleton structure according to claim 11 , wherein each hinge 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.

13. The exoskeleton structure according to claim 11 , wherein the shoulder connection device also comprises an elastic return member capable of exerting a return force tending to oppose deformation of the deformable parallelogram.