Force application device for control stick in a power failure situation

Patent metadata

Field	Value
Publication number	US-11628925-B2
Application number	US-202017771188-A
Country	US
Kind code	B2
Filing date	Oct 23, 2020
Priority date	Oct 23, 2019
Publication date	Apr 18, 2023
Grant date	Apr 18, 2023

Abstract

The present invention relates to a force application device for a control stick of an aircraft comprising a shaft and a control lever configured to rotate the shaft about a first axis, the device comprising: a magnetic brake comprising a braking part configured to be connected to the shaft, and a volume containing a rheological fluid in contact with the braking part, of variable shear resistance as a function of a magnetic field applied to the rheological fluid, a force feedback motor configured to exert a resistive force opposing the rotation of the shaft about the first axis, a motor power source, a movable magnetic element biased towards a position close to the magnetic brake, and distancing means configured to maintain the movable magnetic element in a position away from the magnetic brake, when such distancing means are powered by the power source.

First claim

The invention claimed is:

1. A force application device for a control stick of an aircraft, the control stick comprising a shaft and a control lever configured to drive the shaft in rotation around a first axis, the force application device comprising:
a magnetic brake including:
a braking part configured to be connected to the shaft,
a volume containing a rheological fluid in contact with the braking part, resistance to shear of the rheological fluid being variable as a function of a magnetic field applied to the rheological fluid,

a force feedback motor configured to exert a resistive force opposing the rotation of the shaft around the first axis,
a power source of the force feedback motor,
a movable magnetic element having a position close to the magnetic brake and a position distant from the magnetic brake, the movable magnetic element emitting a magnetic field in the volume in the close position, the movable magnetic element being biased toward
the close position, and
separating means configured to retain the movable magnetic element in the distant position when the separating means are supplied with electrical power by the power source, and configured not to retain the movable magnetic element in the distant position when the separating means are not powered.

2. The force application device according to claim 1 , also comprising return means configured to exert a return force on the movable magnetic element tending to displace the movable magnetic element in the close position, the return force being less than a separating force exerted on the movable magnetic element by the separating means a when the separating means are powered.

3. The force application device according to claim 2 , wherein the separating means comprise a magnetic circuit defining a cavity, the circuit being arranged so that the cavity receives the movable magnetic element in the distant position.

4. The force application device according to claim 1 , wherein the separating means comprise a solenoid.

5. The force application device according to claim 4 , wherein the solenoid is placed opposite to the magnetic brake relative to the movable magnetic element.

6. The force application device according to claim 1 , wherein the rheological fluid comprises a magneto-rheological fluid or a magnetic powder.

7. The force application device according to claim 1 , wherein the control stick comprises a frame, and wherein the magnetic brake comprises a fixed part mounted on the frame, the fixed part delimiting, with the braking part, the volume.

8. The force application device according to claim 1 , wherein the movable magnetic element comprises a permanent magnet.

9. The force application device according to claim 8 , wherein the braking part comprises a brake disk extending in an extension plane, the permanent magnet extending along an axis perpendicular to the extension plane.

10. The force application device according to claim 1 , wherein the movable magnetic element is able to produce an induction magnetic field in the volume greater than a threshold comprised between 0.1 Tesla and 10 Tesla.

11. The force application device according to claim 1 , also comprising an electromagnet configured to generate a variable magnetic field in the volume.

12. The force application device according to claim 1 , also comprising a mechanical joint integral in rotation with the lever around a second axis, and comprising a force sensor configured to exert a force exerted on the mechanical joint around the second axis.

13. The force application device according to claim 1 , wherein the control lever also drives an additional shaft in rotation around a third axis, the force application device also comprising:
an additional magnetic brake able to exert a resistive force to prevent a rotation of the additional shaft around the third axis, said additional brake comprising an additional volume of rheological fluid,
an additional force feedback motor configured to exert a resistive force opposing the rotation of the additional shaft around the third axis,
an additional movable magnetic element having a position close to the additional brake and a position distant from the additional brake, the additional movable magnetic element emitting a magnetic field in the additional rheological fluid volume in the close position, the additional movable magnetic element being biased toward the position close to the additional brake,
additional separating means configured to retain the additional movable magnetic element in the position distant from the additional brake.

14. An active aircraft control stick comprising:
a force application device according to claim 1 ,
a shaft movable in rotation around a first axis and connected to the braking part of the force application device,
a control lever movable in rotation around a second axis, the rotation of the shaft around the first axis being connected to the rotation of the control lever around the second axis.

15. The stick according to claim 14 , also comprising a computer configured to transmit a control signal to the force feedback motor, the resistive force exerted on the shaft by the force feedback motor during the operation of the stick being a function of a set point force value encoded in the control signal.

16. The stick according to claim 15 , wherein the power source of the force feedback motor is configured to supply power to the computer, and wherein the separating means are configured to be deactivated in the event of an electrical failure affecting the computer.

17. Use of a force application device according to claim 1 to prevent, during an electrical failure affecting the power source of the force feedback motor, a rotation of the shaft around the first axis.

Assignees

• Safran Electronics & Defense

Inventors

• Lawniczak Remi-Louis
• Coppée Pascal
• Attrazic Yannick

Classifications

• B64C13/507

  with artificial feel · CPC title

• G05G5/03

  Means for enhancing the operator's awareness of arrival of the controlling member at a command or datum position; Providing feel, e.g. means for creating a counterforce (arrangements for indicating the position of the controlling member G05G1/015) · CPC title

• B64C13/0421 Primary

  control sticks for primary flight controls · CPC title

• G05G9/047

  the controlling member being movable by hand about orthogonal axes, e.g. joysticks {(for switches H01H25/04)} · CPC title

• B64C13/345

  with artificial feel · CPC title