Aircraft flight compensator

Abstract

This aircraft flight trimmer (1) comprises a friction module (2) coupled on one side to a drive shaft (5) and on the other side to an output shaft (7) via a kinematic chain (6), the output shaft (7) being controlled by a control device accessible to an aircraft pilot, the trimmer comprising a control circuit capable of returning the output shaft (7) to a neutral angular position under the action of a restoring force generated by the engine (M) when the user releases a force exerted on the control device of the trimmer (1). Figure for the abbreviation: Fig 1

Description

Title of the invention: Flight compensator for aircraft Technical field

[0001] The invention relates, in general, to flight control systems for aircraft and relates more particularly to a flight compensator for aircraft, in particular for helicopters. Previous techniques

[0002] Flight compensators, or trim, have the function of compensating for disturbances likely to have an influence on the flight parameters of the aircraft, without the pilot having to act on the flight controls.

[0003] In addition, the trim actuators conventionally return to the pilot a resistive force, generally passive, on the flight controls in the form of force feedback.

[0004] In the state of the art, there are two types of trim, namely so-called “gradient trims” and friction trim.

[0005] Current gradient trims generate a torque proportional to the angular displacement of the flight control and return the flight control to the neutral angular position under the action of a spring in the absence of force exerted by the pilot.

[0006] Friction trimmers generate a constant torque, always opposite to the direction of movement of the flight control, and do not return the flight control to the neutral position.

[0007] In view of the above, the present invention aims to propose a simplified architecture of a friction flight compensator making it possible to reproduce the behavior of a gradient compensator.

[0008] More specifically, the invention aims to propose a common flight compensator architecture making it possible to perform the functions of both a gradient compensator and a friction compensator.

[0009] The invention therefore relates to a flight compensator for an aircraft, comprising a friction module coupled on the one hand to a drive shaft and on the other hand to an output shaft via a kinematic chain, the output shaft being controlled by a control member accessible to a pilot of the aircraft.

[0010] The compensator further comprises a control circuit capable of returning the output shaft to a neutral angular position under the action of a return force generated by the motor when the user releases a force exerted on the control member of the compensator.

[0011] Preferably, the return force is generated by the motor in response to a control signal generated by the control circuit.

[0012] Advantageously, the control signal depends on the neutral angular position and on an angular displacement value of the output shaft delivered by a position sensor.

[0013] Preferably, the control signal depends on a motor rotation speed command.

[0014] Advantageously, the neutral angular position can be modified according to instructions from the pilot or an automatic pilot module.

[0015] Advantageously, the friction modulus is a variable friction modulus or a constant friction modulus.

[0016] In one embodiment, the friction module additionally comprises a viscous friction module.

[0017] In one embodiment, the control circuit controls the friction module from an angular displacement value of the output shaft delivered by a position sensor.

[0018] The invention also relates to an aircraft, in particular a helicopter comprising a flight compensator as defined above. Brief description of the drawings

[0019] Other aims, characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example, and made with reference to the appended drawings in which:

[0020] [Fig.l] schematically illustrates the architecture of a flight compensator according to the invention;

[0021] [Fig.2] illustrates a functional diagram of the flight compensator according to the invention; Detailed description of at least one embodiment

[0022] [Fig.l] shows schematically the general architecture of a flight compensator 1, or trim, for a helicopter according to the invention.

[0023] This flight compensator 1 comprises a friction module 2 comprising a connecting shaft 3 coupled via an irreversible reducer 4, for example a worm screw, to a motor shaft 5 driven in rotation by a motor M controlled by a control signal S. The flight compensator 1 also comprises a kinematic chain 6 ensuring the connection and the mechanical reduction between the friction module 2 and an output shaft 7 itself coupled via a system of connecting rods, to the stick (not shown) directly manipulated by the pilot.

[0024] Conventionally, the kinematic chain 6 comprises a gear system as well as end stops, such as 8, and is also equipped with a sensor 9 for measuring the angular position of the output shaft 7.

[0025] Friction module 2 is a controlled variable friction module. However, in other embodiments of the invention, the friction module may comprise a constant friction module, and in both cases the friction module may additionally comprise a viscous friction module.

[0026] The flight compensator 1 further comprises a control circuit comprising an electronic card 10 receiving the angular displacement values ​​of the output shaft 7 delivered by the sensor 9, and providing a haptic command SH to the friction module 2 when the friction module 2 comprises a variable friction module.

[0027] The control circuit also delivers the control signal S to the motor M.

[0028] [Fig.2] illustrates a functional diagram of the flight compensator 1 according to the invention.

[0029] We find the elements of [Fig. 1] with a flight trim actuator 11 comprising the motor M, the friction module 2 generating a friction torque as a function of the haptic command SH. We also find the sensor 9 which can be inside or outside the actuator 11. The motor M, the friction module 2, and the sensor 9 are connected by a mechanical link 12 and are connected to the pilot's stick 13 by the link 12.

[0030] The pilot's stick 13 is integrated into the piloting member 14 available to the pilot. The piloting member 14 therefore comprises the stick 13, and optionally a clutch control 15 and a control for modifying the neutral angular position 16 (usually called a beep control or beep trim control).

[0031] The controls 15 and 16 can be implemented in the form of buttons positioned on the pilot's stick 13.

[0032] The compensator 1 according to the invention may also comprise an automatic piloting module 20.

[0033] We also find in [Fig.2] the control circuit comprising the electronic card 10.

[0034] The electronic card 10 comprises a module 17 for programming the mechanical neutral angular position connected to the two controls 15 and 16 in the case where the compensator 1 integrates these functions.

[0035] The electronic card 10 also comprises a regulation module 18 intended to regulate the mechanical neutral angular position around the programmed neutral angular position and delivering the control signal S to the motor M.

[0036] Finally, the electronic card 2 includes a module 19 for regulating the friction torque.

[0037] In the embodiment in which the friction module 2 is a servo-controlled variable friction module, the module 19 delivers the haptic command SH to the friction module 2.

[0038] In the embodiment in which the friction module 2 is a constant friction module, the module 19 is not included in the electronic card 10.

[0039] Finally, when the compensator 1 comprises a viscous friction module in addition to a constant or variable friction module, the module 19 delivers a speed command Sv of rotation of the motor M to the module 18 so that the module 18 takes this rotation speed into account to develop the control signal of the motor S.

[0040] The module 17 is configured to transmit to the modules 18 and 19 the neutral angular position in a Sanc command. This neutral angular position can be the initial neutral angular position of the output shaft 7 or the virtual neutral angular position defined by the pilot via the module 16 or by the autopilot 20, depending on the case of use of the compensator.

[0041] The module 18 develops the control signal S to be sent to the motor M. The signal S thus depends on the actual neutral or virtual neutral angular position Sanc defined where appropriate by the pilot or the automatic pilot, and programmed in the module 17. The signal S also depends where appropriate on the command Sv for the rotation speed of the motor M developed by the module 18, particularly in the case of a viscous friction module present in the compensator 1. The signal S finally depends on the angular position measured by the sensor 9.

[0042] The electronic card 10 therefore determines the control signal S so that the motor M returns the position of the output shaft 7 of the trim tab 1 to the neutral angular position. In this way, when the pilot releases the stick 13 and therefore no longer exerts any force on the output shaft 7, the torque delivered by the motor M returns the output shaft to the neutral angular position.

[0043] When the pilot takes the stick 13 in hand, he feels this recentering movement exerted by the engine M. To oppose this recentering movement, he must exert a force exceeding that of the friction module 2.

[0044] Module 15 allows the pilot to issue a Semb clutch or disclutch command simulating the operation of an FTR clutch, an acronym for “Force Trim Release”.

[0045] In the case where the friction module 2 comprises only a constant friction module, the motor command S for the return to position is constant regardless of the defined neutral angular position, because the friction is constant. The module 19 is therefore useless.

[0046] In the case where the friction module 2 comprises only a servo-controlled variable friction module, the SH command is a function of the difference between the initial natural neutral angular position and the virtual Sanc angular position defined by the pilot or the automatic pilot 20. The return torque in position is therefore the result of the combination between the friction torque delivered by the friction module 2 and the command S engine.

[0047] In the case where the friction module 2 comprises only a constant friction module and a viscous friction module, the command Sv is a function of the difference between the angular position of the output shaft provided by 9 and the virtual angular position Sanc defined by the pilot or the automatic pilot 20. The same applies to the motor command S.

[0048] Thus, the architecture of the compensator 1 is that of a friction compensator and is capable of adopting the behavior of a gradient trim by performing a return to the neutral angular position of the output shaft 7 by means of the development of a motor command S dependent on the defined neutral angular position Sanc and the angular position information measured by the sensor 9 and allowing the motor M to deliver a return torque in the position of the stick 13.

Claims

Claims

1. Flight compensator (1) for an aircraft, comprising a friction module (2) coupled on the one hand to a drive shaft (5) and on the other hand to an output shaft (7) via a kinematic chain (6), the output shaft (7) being controlled by a piloting member (14) accessible to a pilot of the aircraft, characterized in that it comprises a control circuit capable of returning the output shaft (7) to a neutral angular position under the action of a return force generated by the engine (M) when the user releases a force exerted on the piloting member (14) of the compensator (1), the friction module (2) being a constant friction module.

2. Compensator according to claim 1, in which the restoring force is generated by the motor (M) in response to a control signal (S) generated by the control circuit.

3. Compensator according to claim 2, in which the control signal (S) depends on the neutral angular position (Sanc) and on an angular displacement value of the output shaft delivered by a position sensor (9).

4. Compensator according to claim 3, in which the control signal (S) depends on a command (Sv) of rotation speed of the motor M.

5. Compensator according to one of claims 1 to 4, in which the neutral angular position can be modified according to instructions from the pilot or from an automatic pilot module (20).

6. A compensator according to claim 5, wherein the friction module (2) comprises a viscous friction module.

7. Compensator according to one of claims 3 to 6, in which the control circuit controls the friction module (2) from the angular displacement value of the output shaft (7) delivered by the position sensor (9).

8. Aircraft, in particular a helicopter comprising a flight compensator (1) according to any one of claims 1 to 7.

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