Force feedback interface with improved sensation

1. An haptic interface comprising:

an element that interacts with a user, a rotation shaft with a longitudinal axis to which the user interaction element is fixed in rotation;

an element that interacts with a fluid, the fluid interaction element being fixed in rotation to the shaft, the fluid being of magneto-rheological type;

a system that generates a magnetic field in the fluid configured to modify viscosity of the fluid;

a control unit configured to generate orders to the magnetic field generation system so as to modify the magnetic field;

a housing containing the interaction element, the magneto-rheological fluid, and the system for generating a magnetic field, the housing including a sidewall and two end walls, the rotation shaft passing through one of the end walls and penetrating inside the housing, the housing forming a sealed chamber confining the magneto-rheological fluid; wherein

the user interaction element is arranged outside the housing,

the system for generating a magnetic field comprising means for generating a variable magnetic field and means for generating a permanent magnetic field, the means for generating a permanent magnetic field being arranged in the housing to cause an increase in the fluid viscosity in absence of a system electrical power supply, and

the means for generating a variable magnetic field and the means for generating a permanent magnetic field are each located inside the fluid interaction element and are each immobile relative to the housing.

2. The haptic interface according to claim 1 , further comprising at least one angular position, angular velocity, and/or angular acceleration sensor of the shaft, the control unit generating orders as a function of information provided by the at least one angular position, velocity, and/or acceleration sensor.

3. The haptic interface according to claim 1 , in which the control unit generates orders to the magnetic field generation system at given fixed or variable time intervals.

4. The haptic interface according to claim 1 , in which the system for generating a permanent magnetic field generates a radial magnetic field.

5. The haptic interface according to claim 1 , in which the means for generating a permanent magnetic field comprises at least one permanent magnet.

6. The haptic interface according to claim 1 , in which the means for generating a variable magnetic field comprises at least an electromagnetic coil.

7. The haptic interface according to claim 1 , in which the fluid interaction element comprises at least one cylindrical wall of revolution with a longitudinal axis and a head made from a non-magnetic material, the head being fixed to the rotation shaft, the fluid coming into contact on an inner face and an outer face of the sidewall.

8. The haptic interface according to claim 7 , in which the fluid interaction element comprises plural concentric sidewalls at a spacing from each other and fixed to the head made of non-magnetic material.

9. The haptic interface according to claim 1 , in which the means for generating a variable magnetic field comprises at least an electromagnetic coil and the means for generating a permanent magnetic field comprises at least one permanent magnet, the coil surrounding the permanent magnet.

10. The haptic interface according to claim 1 , in which the means for generating a variable magnetic field comprises at least an electromagnetic coil and the means for generating a permanent magnetic field comprises at least one permanent magnet, the permanent magnet including at least one sleeve surrounding the coil.

11. The haptic interface according to claim 6 , in which the means for generating a permanent magnetic field is fixed relative to the housing.

12. The haptic interface according to claim 1 , in which the shaft passes through the magnetic field generation system.

13. The haptic interface according to claim 2 , in which the angular position, angular velocity, or angular acceleration sensor is provided at one shaft longitudinal end and comprises a part fixed in rotation with the shaft and a part immobile relative to the shaft.

14. The haptic interface according to claim 13 , in which the part fixed on the shaft is an optical wheel and the immobile part is an optical fork.

15. The haptic interface according to claim 1 , further comprising:

a rod passing through the shaft from one side to the other, the rod configured to move longitudinally; and

a device for detecting displacement of the rod.

16. The haptic interface according to claim 1 , further comprising a thermal device configured to modify a temperature of the user interaction element.

17. The haptic interface according to claim 16 , in which the thermal device comprises at least one Peltier cell.

18. The haptic interface according to claim 16 , further comprising a device configured to vibrate the user interaction element.

19. The haptic assembly comprising:

a frame; and

the interface according to claim 1 , mounted on the frame,

the interface being free to move along the axis of the shaft.

20. The haptic assembly according to claim 19 , in which the interface is free to move in translation along at least one direction orthogonal to the longitudinal axis.

21. The haptic assembly according to claim 19 , in which the interface is free to move in rotation about at least one direction orthogonal to the longitudinal axis.

22. The haptic assembly according to claim 20 , further comprising force feedback devices to oppose a resistance during a movement along at least one axis orthogonal to or about the longitudinal axis.

23. The haptic assembly according to claim 21 , further comprising force feedback devices to oppose a resistance during a movement along at least one axis orthogonal to or about the longitudinal axis.