Actuation of a hand intended for being provided on a humanoid robot

1. A hand intended for a humanoid robot, the hand comprising:

a palm and several fingers that are motorized relative to the palm,

an actuator common to the several fingers, and

a spreader to distribute a force exerted by the actuator toward the fingers,

wherein there are defined, in a frontal plane at right angles to a direction in which the force exerted by the actuator is oriented, a projection in said frontal plane of a point of application on the spreader of the force exerted by the actuator and projections in said frontal plane of points of application on the spreader of forces, exerted by the fingers, and

wherein there is defined, in the frontal plane, a vertical direction at right angles to an intersection of the frontal plane and of a horizontal plane containing a direction in which the force exerted by the actuator is oriented and in which the palm of the hand mainly extends, and

wherein, according to the vertical direction, the projection in said frontal plane of the point of application on the spreader of the force exerted by the actuator is positioned substantially at a barycenter of the projections in said frontal plane of the points of application on the spreader of the forces exerted by the fingers, the projections in said frontal plane of the points of application on the spreader of the forces exerted by the fingers not all coinciding.

2. The hand as claimed in claim 1 ,

wherein there are defined, in the horizontal plane containing the direction in which the force exerted by the actuator is oriented and in which the palm of the hand mainly extends, a projection in said horizontal plane of the point of application on the spreader of the force exerted by the actuator and projections in said horizontal plane of points of application on the spreader of the forces exerted by the fingers, and

wherein there is defined a frontal direction parallel to the direction in which the force exerted by the actuator is oriented, and

wherein, by considering the projection in said horizontal plane of the point of application on the spreader of the force exerted by the actuator as an origin of a coordinate axis along said frontal direction, and by considering the direction in which the actuator pulls on the spreader to be a positive direction along said coordinate axis along said frontal direction, abscissae of the projections of the points of application on the spreader of the forces exerted by the fingers are all negative values on said coordinate axis along said frontal direction.

3. The hand as claimed in claim 2 , wherein the several fingers comprise four fingers linked to the spreader, of which a first finger forms an index finger, a second forms a middle finger, a third forms a ring finger and a fourth forms a little finger, and

wherein, in the projection in said horizontal plane and relative to the coordinate axis along said frontal direction and as an absolute value, an abscissa of the point of application of the force exerted by the little finger is smallest of the four fingers, an abscissa of the point of application of the force exerted by the middle finger is greatest of the four fingers, and abscissae of the points of application of the forces exerted by the index finger and the ring finger have values between the abscissa of the of the point of application of the force exerted by the little finger and the abscissa of the of the point of application of the force exerted by the middle finger.

4. The hand as claimed in claim 3 , wherein the four fingers linked to the spreader are identical.

5. The hand as claimed in claim 1 , wherein there are defined, in the horizontal plane containing a direction in which the force exerted by the actuator is oriented and in which the palm of the hand mainly extends, a projection in said horizontal plane of the point of application on the spreader of the force exerted by the actuator and projections in said horizontal plane of the points of application on the spreader of the forces exerted by the fingers, and

wherein, according to a direction of the horizontal plane at right angles to the direction in which the force exerted by the actuator is oriented, the projection in said horizontal plane of the point of application of the force exerted by the actuator is situated at a barycenter of the projection in said horizontal plane of the points of application of the forces exerted by the fingers linked to the spreader.

6. The hand as claimed in claim 1 , wherein the spreader extends mainly in the horizontal plane containing a direction in which the force exerted by the actuator is oriented and in which the palm of the hand mainly extends.

7. The hand as claimed in claim 1 , wherein the actuator is a dual-acting actuator and comprising a single spreader linked to the dual-acting actuator.

8. The hand as claimed in claim 1 , further comprising two spreaders making it possible to motorize each of the fingers by dual action.

9. The hand as claimed in claim 8 , further comprising a dual-acting actuator common to the two spreaders.

10. The hand as claimed in claim 9 , wherein the actuator common to the two spreaders acts on the two spreaders via a cable winding on a pulley driven in rotation by the actuator common to the two spreaders.

11. The hand as claimed in claim 1 , further comprising stops limiting the displacement of the spreader.

12. The hand as claimed in claim 1 , further comprising a thumb and wherein the actuator exerts a force on the thumb independently of the spreader.

13. A humanoid robot, further comprising a hand as claimed in claim 1 .