Reducing gust loads acting on an aircraft

Abstract

Device and method for reducing gust loads acting on control surfaces of an aircraft. Each control surface is movable by at least one actuator, and a flight control system provides reference variables X.sub.soll and {dot over (X)}.sub.soll to actuate the actuator of each control surface. X.sub.soll indicates a target position, force, or moment of the actuator, and {dot over (X)}.sub.soll indicates a time derivative of X.sub.soll. The device includes: a first sensor system identifying a position, force, or moment, indicated by variable F.sub.ext,Boe, as produced by gusts acting from outside on the control surface; and a regulator regulating the actuator of the control surface based on F.sub.ext,Boe, X.sub.soll and {dot over (X)}.sub.soll, and X.sub.A and {dot over (X)}.sub.A, resulting from the actuator acting on the control surface and detected by a second sensor system, wherein regulation of the actuator by the regulator enables compensation of the position, force, or moment produced by gusts acting on the control surface.

Claims

1. An apparatus to reduce gust loads acting on a number n of aerodynamic control surfaces of an aircraft, with n≥1, wherein each aerodynamic control surface of the aerodynamic control surfaces is movable by at least one actuator, and a flight control system provides reference variables X.sub.soll and {dot over (X)}.sub.soll for actuating the at least one actuator of each aerodynamic control surface, wherein X.sub.soll indicates a target position, a target force, or a target moment associated with the at least one actuator, and {dot over (X)}.sub.soll indicates a time derivative of X.sub.soll, wherein per aerodynamic control surface the apparatus comprises: a first sensor system configured to identify a position, force, or moment produced by gusts acting from outside the aircraft on the aerodynamic control surface, wherein the position, force, or moment is indicated by a variable F.sub.ext,Boe; a regulator configured to output a control variable S.sub.RE based on the variable F.sub.ext,Boe, the reference variables X.sub.soll and {dot over (X)}.sub.soll, and reference variables X.sub.A and {dot over (X)}.sub.A, the reference variables X.sub.A and {dot over (X)}.sub.A resulting from the at least one actuator acting on the aerodynamic control surface as detected by a second sensor system associated with the aerodynamic control surface; and a feed-forward controller configured to output a control variable S.sub.FV based on the reference variables X.sub.soll and {dot over (X)}.sub.soll, and the reference variables X.sub.A and {dot over (X)}.sub.A, wherein the at least one actuator is regulated with a control variable S.sub.SOLL which is a sum of the control variable S.sub.FV of the feed-forward controller and the control variable S.sub.RE of the regulator: S.sub.SOLL=S.sub.FV+S.sub.RE, wherein regulation of the at least one actuator enables compensation of the position, force, or moment produced by gusts acting on the aerodynamic control surface.

2. The apparatus according to claim 1, wherein the regulator has a processor PR1 which works with a processor frequency PT1, and the flight control system has a processor PR.sub.F which works with a processor frequency PT2, wherein PT1>PT2.

3. The apparatus according to claim 1, wherein the regulator uses the following regulating model:
S.sub.RE=(X.sub.A−X.sub.soll)*c+({dot over (X)}.sub.A−{dot over (X)}.sub.soll)*d with: S.sub.RE: control variable of the regulator, indicating a position, force, or moment, X.sub.A: regulating variable which indicates a position, force, or moment, {dot over (X)}.sub.A: regulating variable which indicates a time derivative of the regulating variable X.sub.A, X.sub.soll: reference variable which indicates a position, force, or moment, {dot over (X)}.sub.soll: reference variable which indicates a time derivative of the reference variable X.sub.soll, c: rigidity, and d: dampening.

4. The apparatus according to claim 1, wherein the regulator uses the following regulating model:
S.sub.RE=X.sub.soll+F.sub.ext,Boe*k+{dot over (X)}.sub.A*d with: S.sub.RE: control variable of the regulator, indicating a position, force, or moment, X.sub.soll: reference variable which indicates a target position, force, or moment of the actuator, F.sub.ext,Boe: variable indicating position, force, or moment as a result of gusts on the control surface, X.sub.A: regulating variable which indicates a position, force, or moment, {dot over (X)}.sub.A: regulating variable which indicates a time derivative of the regulating variable X.sub.A, k: constant, and d: dampening.

5. The apparatus according to claim 1, wherein the at least one actuator includes an electric motor.

6. The apparatus according to claim 5, wherein a current of the electric motor is regulated based on the control variable S.sub.SOLL.

7. The apparatus according to claim 1, wherein: the first sensor system is configured to measure a total force F.sub.ext,Ges acting from outside the aircraft on the aerodynamic control surface, F.sub.ext,Ges=F.sub.ext,Boe+F.sub.ext,Rest, wherein F.sub.ext,Rest: air force acting on the aerodynamic control surface without a presence of gusts: F.sub.ext,Boe=0; and the first sensor system is further configured to estimate an air force F.sub.ext,Rest* acting on the aerodynamic control surface without presence of gusts, based on the reference variables X.sub.soll and {dot over (X)}.sub.soll, a current flight speed of the aircraft V.sub.LufFZ, a current flight altitude H.sub.LufFZ of the aircraft, and a current temperature T.sub.LufFZ of air surrounding the aircraft, wherein F.sub.ext,Boe is calculated as follows: F.sub.ext,Boe=F.sub.ext,Ges−F.sub.ext,Rest*.

8. An aircraft with an apparatus according to claim 1.

9. The apparatus according to claim 1, wherein the regulator has a processor PR1 which works with a processor frequency PT1, and the flight control system has a processor PR.sub.F which works with a processor frequency PT2, wherein PT1>2*PT2.

10. A method of reducing gust loads acting on a number n of aerodynamic control surfaces of an aircraft, with n≥1, wherein each aerodynamic control surface of the aerodynamic control surfaces is movable by at least one actuator, and a flight control system provides reference variables X.sub.soll and {dot over (X)}.sub.soll for actuating the at least one actuator of each aerodynamic control surface, wherein X.sub.soll indicates a target position, a target force, or a target moment associated with the at least one actuator, and {dot over (X)}.sub.soll indicates a time derivative of X.sub.soll, wherein per aerodynamic control surface the method comprises: identifying, using a first sensor system, a position, force, or moment produced by gusts acting from outside the aircraft on the aerodynamic control surface, wherein the position, force, or moment is indicated by a variable F.sub.ext,Boe; outputting, using a regulator, a control variable S.sub.RE based on the variable F.sub.ext,Boe, the reference variables X.sub.soll and {dot over (X)}.sub.soll, and reference variables X.sub.A and {dot over (X)}.sub.A, the reference variables X.sub.A and {dot over (X)}.sub.A resulting from the at least one actuator acting on the aerodynamic control surface as detected by a second sensor system associated with the aerodynamic control surface; and outputting, using a feed-forward controller, a control variable S.sub.FV based on the reference variables X.sub.soll and {dot over (X)}.sub.soll, and the reference variables X.sub.A and X.sub.A, wherein the at least one actuator is regulated with a control variable S.sub.SOLL which is a sum of the control variable S.sub.FV of the feed-forward controller and the control variable S.sub.RE of the regulator: S.sub.SOLL=S.sub.FV+S.sub.RE, wherein regulation of the at least one actuator enables compensation of the position, force, or moment produced by gusts acting on the aerodynamic control surface.

11. The method according to claim 10, wherein the method comprises: providing the regulator with a processor PR1 which works with a processor frequency PT1; and providing the flight control system with a processor PR.sub.F which works with a processor frequency PT2, wherein PT1>PT2.

12. The method according to claim 10, wherein the method comprises: providing the regulator with a processor PR1 which works with a processor frequency PT1; and providing the flight control system with a processor PR.sub.F which works with a processor frequency PT2, wherein PT1>2*PT2.

13. The method according to claim 10, wherein the method comprises the regulator using the following model:
S.sub.RE=(X.sub.A−X.sub.soll)*c+({dot over (X)}.sub.A−{dot over (X)}.sub.soll)*d with: S.sub.RE: control variable of the regulator, indicating a position, force, or moment, X.sub.A: regulating variable which indicates a position, force, or moment, {dot over (X)}.sub.A: time derivative of the regulating variable X.sub.A, X.sub.soll: reference variable which indicates a position, force, or moment, {dot over (X)}.sub.soll: reference variable which indicates a time derivative of the reference variable X.sub.soll, c: rigidity, and d: dampening.

14. The method according to claim 10, wherein the method comprises the regulator using the following regulating model:
S.sub.RE=X.sub.soll+F.sub.ext,Boe*k+{dot over (X)}.sub.A*d with: S.sub.RE: control variable of the regulator, indicating a position, force, or moment, X.sub.soll: a target position, force, or moment of the actuator, F.sub.ext,Boe: variable indicating position, force, or moment as a result of gusts on the control surface, X.sub.A: regulating variable which indicates a position, force, or moment, {dot over (X)}.sub.A: regulating variable which indicates a time derivative of the regulating variable X.sub.A, k: constant, and d: dampening.

15. The method according to claim 10, wherein the at least one actuator includes an electric motor.

16. The method according to claim 15, wherein regulation comprises regulating a current of the electric motor based on the control variable S.sub.SOLL.

17. The method according to claim 10, wherein the method comprises: measuring, using the first sensor system, a total force F.sub.ext,Ges acting from outside the aircraft on the aerodynamic control surface, F.sub.ext,Ges=F.sub.ext,Boe+F.sub.ext,Rest, wherein F.sub.ext,Rest: air force acting on the aerodynamic control surface without a presence of gusts: F.sub.ext,Boe=0; and estimating, using the first sensor system an air force F.sub.ext,Rest* acting on the aerodynamic control surface without presence of gusts, based on the reference variables X.sub.soll and {dot over (X)}.sub.soll, a current flight speed of the aircraft V.sub.LufFZ, a current flight altitude H.sub.LufFZ of the aircraft, and a current temperature T.sub.LufFZ the air surrounding the aircraft, wherein F.sub.ext,Boe is calculated as follows: F.sub.ext,Boe=F.sub.ext,Ges−F.sub.ext,Rest*.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings:

(2) FIG. 1 shows a schematic diagram of an apparatus according to the invention;

(3) FIG. 2 shows a schematic flow diagram of a method according to an embodiment of the invention; and

(4) FIG. 3 shows a schematic flow diagram of a method according to another embodiment of the invention.

DETAILED DESCRIPTION

(5) FIG. 1 shows a schematic diagram of an apparatus according to the invention for reducing gust loads acting on a number n of an aerodynamic control surfaces of an aircraft, with n≥1. For example, the aircraft has an aerodynamic control surface 101, herein an elevator, which is movable by an actuator 102. Furthermore, the aircraft has a flight control system 103, which receives control specifications SV.sub.Pilot from input means 110 for a pilot, as well as control specifications SV.sub.AutoPilot from an autopilot 109. The input means 110 includes rudder pedals for specifying control signals for movement of the aircraft about the vertical axis, as well as a so-called “side stick” for specifying control signals for movements of the aircraft about the transverse and longitudinal axes. The flight control system 103 processes the control specifications of the input means 110 as well as the autopilot 109, and generates reference variables X.sub.soll and {dot over (X)}.sub.soll for actuating the actuator 102 of each aerodynamic control surface 101, for example, X.sub.soll herein indicates a target position of the actuator 102 and {dot over (X)}.sub.soll indicates a time derivative of X.sub.soll. It should be noted that the reference variable {dot over (X)}.sub.soll can indicate a target position, force, or moment of the actuator 102, a drive terrain between the actuator 102 and the aerodynamic control surface 101, or the aerodynamic control surface 101. The apparatus includes a feed-forward controller 106 which receives reference variables X.sub.soll and {dot over (X)}.sub.soll, and control variables X.sub.A and {dot over (X)}.sub.A generated as a result of the actuator 102 acting on the control surface 101, and generates a regulating variable S.sub.FV for regulating the actuator 102.

(6) The apparatus includes a first sensor system (S1) 104 which identifies a position, force, or moment, indicated by a variable F.sub.ext,Boe, produced by gusts acting from outside the aircraft on the control surface 101.

(7) Furthermore, the apparatus includes a regulator 105 for regulating the actuator 102 based on the following variables: the variable F.sub.ext,Boe, the reference variables: X.sub.soll and {dot over (X)}.sub.soll, and control variables: X.sub.A and {dot over (X)}.sub.A generated as a result of the actuator 102 acting on the control surface 101 and detected by a second sensor system (S2) 120, wherein the sensor system 120 has a position sensor between the actuator 102 and the control surface 101 for identifying the control variables in a drive train of the actuator 102. The actuator 102 can include an electric motor (M) 102a that drives the drive train of the actuator. It should be noted that the second sensor system 120 can have an appropriate sensor (position, force, or moment sensor) in order to identify an actual position, force, or moment associated with the actuator 102, the drive terrain between the actuator 102 and the control surface 101, or the control surface 101. Thus, the control variable X.sub.A can indicate an actual position, force, or moment of the actuator 102, the drive terrain, or the control surface 101 as a result of the actuator 102 acting on the control surface 101, and the variable {dot over (X)}.sub.A indicates a time derivative of the variable X.sub.A.

(8) According to the invention, the regulator 105 is designed and equipped in such a way that it has a regulation behavior which enables the compensation of the position, force, or moment produced by gusts, as indicated by the variable F.sub.ext,Boe, on the control surface 101 of the aircraft. In particular, the regulator 105 receives F.sub.ext,Boe, X.sub.soll and {dot over (X)}.sub.soll, and X.sub.A and {dot over (X)}.sub.A, and generates a regulating variable S.sub.RE which regulates the actuator 102, such as by regulating a current of the electric motor 102a of the actuator 102 based on the regulating variable S.sub.RE. In those cases where a feed-forward controller 106 is provided, regulating variable output of the feed-forward controller 106 provides a regulating variable S.sub.FV, and regulating variable output of the regulator 105 provides a regulating variable S.sub.RE. Both regulating variables are combined as a single regulating variable S.sub.SOLL, =S.sub.FV+S.sub.RE in an adder 108. These elements are illustrated in FIG. 1 using dashed lines for clarity. Accordingly, the regulating variable S.sub.SOLL, is used as a regulating input to the actuator 102 which acts on the control surface 101 based on S.sub.SOLL, thus providing compensation of the position, force, or moment produced by gusts on the control surface 101. Similarly to the regulating variable S.sub.RE, the regulating variable S.sub.SOLL can be used to regulate the current of the electric motor 102a of the actuator 102.

(9) FIG. 2 shows a schematic flow diagram of a method according to an embodiment of the invention for reducing gust loads acting on a number n of aerodynamic control surfaces of an aircraft, with n≥1, wherein each aerodynamic control surface 101 is movable by at least one actuator 102, and a flight control system 103 provides reference variables: X.sub.soll and {dot over (X)}.sub.soll for actuating the actuator 102 of each aerodynamic control surface 101, wherein X.sub.soll indicates a target position, a target force, or a target moment of the actuator 102, and {dot over (X)}.sub.soll indicates a time derivative of X.sub.soll. The method includes the following steps. In a first step 201, a position, force, or moment produced by gusts acting from outside the aircraft on the control surface 101, as indicated by a variable F.sub.ext,Boe, is identified by a first sensor system (S1) 104. In a second step 202, the actuator 102 is regulated using the regulator 105 based on: the variable F.sub.ext,Boe, the reference variables: X.sub.soll and {dot over (X)}.sub.soll, and the regulating variables generated as a result of the actuator 102 acting on the control surface 101 and detected by a second sensor system (S2) 120: X.sub.A and {dot over (X)}.sub.A, wherein the regulation carried out in such a way that the position, force, or moment produced by gusts on the control surface 101 is compensated.

(10) FIG. 3 shows a schematic flow diagram of another method according to another embodiment of the invention for reducing gust loads acting on a number n of aerodynamic control surfaces of an aircraft, with n≥1, wherein each aerodynamic control surface 101 is movable by at least one actuator 102, and a flight control system 103 provides reference variables: X.sub.soll and {dot over (X)}.sub.soll for actuating the actuator 102 of each aerodynamic control surface 101, wherein X.sub.soll indicates a target position, a target force, or a target moment of the actuator 102, and {dot over (X)}.sub.soll indicates a time derivative of X.sub.soll. The method includes the following steps. In a first step 301, a position, force, or moment produced by gusts acting from outside the aircraft on the control surface 101, as indicated by a variable F.sub.ext,Boe, is identified by a first sensor system (S1) 104. In a second step 302, a regulating variable S.sub.RE is output from a regulator 105 based on F.sub.ext,Boe identified by the first sensor system (S1) associated with the control surface 101, X.sub.soll and {dot over (X)}.sub.soll provided by the flight control system 103, and X.sub.A and {dot over (X)}.sub.A resulting from the actuator 102 acting on the control surface 101 as detected by the second sensor system (S2) 120 associated with the control surface 101. In a third step 303, a regulating variable S.sub.FV is output from a feed-forward controller 106 based on the reference variables X.sub.soll and {dot over (X)}.sub.soll provided by the flight control system 103, and reference variables X.sub.A and {dot over (X)}.sub.A resulting from the actuator 102 acting on the control surface 101 as detected by the second sensor system (S2) 120 associated with the control surface 101. In the fourth step, the actuator 102 of the control surface 101 is regulated based on a regulating variable S.sub.SOLL=S.sub.FV+S.sub.RE, as output by an adder 108 based on respective regulating outputs from the feed-forward controller 106 and the regulator 105, wherein regulation of the actuator 102 enables compensation of the position, force, or moment produced by gusts acting on the control surface 101.

(11) Although the invention has been further illustrated and explained by way of preferred example embodiments, the invention is not limited by the disclosed examples and other variations can be derived therefrom by the person skilled, without departing from the scope of the invention. It is thus understood that a plurality of possible variations exists. It is also understood that embodiments presented by way of example are really merely examples that should not be construed as limiting the scope, the possible applications or the configuration of the invention in any way. The above description and the description of the figures rather enable the person skilled in the art to concretely implement the example embodiments, wherein the person skilled in the art, in the knowledge of the disclosed inventive concept, can make numerous changes, for example, with respect to the function or the arrangement of individual elements, mentioned in an example embodiment, without departing from the scope defined by the claims and their legal equivalences, such as further explanations in the description.

LIST OF REFERENCE NUMERALS

(12) 101 control surface 102 actuator 102a motor of actuator 103 flight control system 104 first sensor system (S1) for detecting variable F.sub.ext,Boe 105 regulator 106 feed-forward controller 108 adder 109 autopilot 110 input means for input of control specifications by a pilot 120 second sensor system (S2) for detecting regulating variables X.sub.A and X.sub.A SV.sub.AutoPilot control specifications from the autopilot SV.sub.Pilot control specifications from the pilot X.sub.soll target position, force, or moment of the actuator {dot over (X)}.sub.soll time derivative of X.sub.soll S.sub.FV control variable of the feed-forward controller S.sub.RE control variable of the regulator S.sub.SOLL control variable as a sum of S.sub.FV and S.sub.RE X.sub.A regulating variable of the actuator indicating position, force, or moment {dot over (X)}.sub.A regulating variable of the actuator indicating time derivative of X.sub.A F.sub.ext,Boe variable indicating position, force, or moment produced as a result of gusts on the control surface 201, 202 method steps 301-304 method steps