Device for assisting the piloting of a rotorcraft

1. A piloting assistance device for assisting the piloting of a rotorcraft, the rotorcraft being provided with a flight control for controlling a rotor via at least one linkage provided with a plurality of rods including at least intermediate rod and link means, wherein the device comprises:

an instantaneous force sensor secured to an intermediate rod;

determination means for determining a position of the flight control; and

piloting assistance means having at least one electric motor controlled by control means to drive an outlet shaft connected to the link means in parallel with the at least one linkage, the piloting assistance means including at least one of

an electric motor position sensor for determining an angular position of the at least one electric motor, and

an outlet shaft position sensor for sensing a position of the outlet shaft.

2. A piloting assistance device according to claim 1 , further including at least one autopilot means for controlling the piloting assistance means.

3. A piloting assistance device according to claim 1 , further including a friction unit arranged between the control means and a series actuator to generate a friction force greater than the friction force of a linkage between the series actuator and the rotor.

4. A piloting assistance device according to claim 1 , wherein the rotorcraft is provided with at least two linkages, each having a plurality of rods including at least one intermediate rod and link means, the piloting assistance device further comprising

one instantaneous force sensor arranged in the intermediate rod of an associated linkage; and

a single piloting assistance means per linkage that is connected to the link means in parallel with the associated linkage.

5. A piloting assistance device according to claim 1 , wherein the electric motor is connected to an outlet shaft successively via gearing and fuse means, the fuse means comprising

a first wheel provided with teeth on an outer periphery that co-operate with the gearing and with driving teeth on an inner periphery, the driving teeth moving axially relative to the gearing;

driven teeth arranged on the outlet shaft for co-operating with the driving teeth; and

a stationary electrical coil for attracting the driving teeth against the driven teeth when the coil is electrically powered by the control means.

6. A piloting assistance device according to claim 1 , wherein the piloting assistance means commands an additional force in response to the difference between a setpoint force and a measured instantaneous force.

7. A piloting assistance device according to claim 6 , wherein the setpoint force is determined in response to a pre-established force relationship.

8. A piloting assistance device according to claim 7 , wherein the pre-established force relationship varies as a function of flying conditions.

9. A piloting assistance device according to claim 1 , wherein the instantaneous force sensor is an electronic sensor.

10. A piloting assistance device according to claim 1 , wherein the instantaneous force sensor is a strain gauge type force sensor.

11. A piloting assistance device according to claim 1 , wherein the instrumentation means is an angle sensor connected to the flight control.

12. A piloting assistance device for assisting the piloting of a rotorcraft, the rotorcraft being provided with a flight control for controlling a rotor via at least one linkage provided with a plurality of rods including at least intermediate rod and link means, wherein the device comprises:

an instantaneous force sensor arranged in an intermediate rod;

determination means for determining a position of the flight control; and

piloting assistance means having at least one electric motor controlled by control means to drive an outlet shaft connected to the link means in parallel with the at least one linkage, the piloting assistance means including

at least a first position sensor for determining an angular position of the at least one electric motor, and

at least a second position sensor for sensing a position of the outlet shaft.

13. A piloting assistance device according to claim 12 , wherein the piloting assistance means commands an additional force in response to the difference between a setpoint force and a measured instantaneous force.

14. A piloting assistance device according to claim 13 , wherein the setpoint force is determined in response to a pre-established force relationship.

15. A piloting assistance device according to claim 14 , wherein the pre-established force relationship varies as a function of flying conditions.

16. A piloting assistance device for assisting the piloting of a rotorcraft, the rotorcraft being provided with a flight control for controlling a rotor via at least one linkage provided with a plurality of rods including at least intermediate rod and link means, wherein the device comprises:

an instantaneous force sensor arranged in an intermediate rod;

determination means for determining a position of the flight control; and

piloting assistance means having at least one electric motor controlled by control means to drive an outlet shaft connected to the link means in parallel with the at least one linkage, the piloting assistance means including

a position sensor selected from the group consisting of an electric motor position sensor for determining an angular position of the at least one electric motor and an outlet shaft position sensor for sensing a position of the outlet shaft.

17. A piloting assistance device according to claim 16 , wherein the piloting assistance means commands an additional force in response to the difference between a setpoint force and a measured instantaneous force.

18. A piloting assistance device according to claim 17 , wherein the setpoint force is determined in response to a pre-established force relationship.

19. A piloting assistance device according to claim 18 , wherein the pre-established force relationship varies as a function of flying conditions.

20. A piloting assistance device according to claim 16 , wherein the instantaneous force sensor is an electronic sensor.