Closed loop control of aircraft control surfaces

Patent metadata

Field	Value
Publication number	US-9821903-B2
Application number	US-201414330824-A
Country	US
Kind code	B2
Filing date	Jul 14, 2014
Priority date	Jul 14, 2014
Publication date	Nov 21, 2017
Grant date	Nov 21, 2017

Abstract

Closed loop control of control surfaces is described herein. One disclosed example method includes measuring a flight metric of an aircraft during flight and calculating, using a processor, a deflection of a control surface of the aircraft based on the flight metric. The disclosed example method also includes adjusting the deflection to an effective deflection level based on the calculated deflection to reduce a drag coefficient of the aircraft.

First claim

What is claimed is:

1. A method comprising:
measuring a flight metric of an aircraft during cruise of the aircraft;
calculating, using a processor, a first deflection based on the measured flight metric;
inducing a perturbation deflection of a control surface based on the calculated first deflection;
re-measuring the flight metric of the aircraft in response to the induced perturbation deflection to gather data about a drag coefficient pertaining to the aircraft during cruise;
calculating, using the processor, a second deflection of the control surface of the aircraft based on the re-measured flight metric by adding a perturbation estimate increment to a deflection estimate that reduces drag; and
adjusting the control surface to the second deflection to reduce the drag coefficient of the aircraft during cruise.

2. The method as defined in claim 1 , wherein adjusting the control surface comprises adjusting a wing camber.

3. The method as defined in claim 1 , wherein the flight metric comprises an amount of thrust.

4. The method as defined in claim 1 , wherein calculating at least one of the first and second deflections comprises using a Kalman-filter based method to estimate a sensitivity of the flight metric.

5. The method as defined in claim 1 , wherein calculating at least one of the first and second deflections comprises using a drag value, a trim thrust value, or a percent throttle value.

6. A method comprising:
measuring a flight metric of an aircraft during cruise of the aircraft;
inducing a perturbation deflection of a control surface of the aircraft to a first angle based on the measured flight metric;
re-measuring the flight metric in response to the induced perturbation deflection to gather data about a drag coefficient pertaining to the aircraft during cruise;
calculating, using a processor, a second angle of the control surface based on the re-measured flight metric and one or more of a flight condition, or the measured flight metric, wherein the second angle includes an adjustment angle to reduce the drag coefficient of the aircraft during cruise; and
adjusting the control surface to the second angle.

7. The method as defined in claim 6 , wherein the flight metric comprises an amount of thrust.

8. The method as defined in claim 6 wherein at least one of adjusting the first angle or the second angle comprises adjusting a wing camber.

9. The method as defined in claim 6 , wherein calculating the second angle comprises using a Kalman-filter based method to estimate a sensitivity of the flight metric.

10. The method as defined in claim 6 , wherein calculating the second angle comprises estimating drag in response to a deflection of the control surface.

11. The method as defined in claim 6 , wherein calculating the second angle comprises using one or more of a drag value, a trim thrust value, table lookup data or a percent throttle value.

12. The method as defined in claim 6 , wherein calculating the second angle is further based on table lookup data.

13. A method comprising:
adjusting an aircraft control surface to a first angle during cruise of the aircraft;
measuring a flight metric after the aircraft reaches steady state during cruise;
calculating, using a processor, a deflection of the aircraft control surface based on the measured flight metric;
inducing a perturbation deflection of the aircraft control surface based on the calculated deflection;
re-measuring the flight metric in response to the induced perturbation deflection to gather data about a drag coefficient pertaining to the aircraft during cruise;
calculating, using the processor, a second angle of the aircraft control surface based on the re-measured flight metric to reduce the drag coefficient of the aircraft during cruise, wherein the second angle includes an adjustment angle; and
adjusting the aircraft control surface to the second angle.

14. The method as defined in claim 13 , further comprising calculating a level of convergence between the first angle and the second angle to determine whether to readjust the aircraft control surface.

15. The method as defined in claim 13 , wherein the first angle is determined from table lookup data.

16. The method as defined in claim 13 , wherein calculating the second angle comprises adding the perturbation deflection to a deflection estimate that reduces drag.

17. The method as defined in claim 13 , wherein calculating the second angle comprises using a quadratic estimate.

18. The method as defined in claim 13 , wherein calculating the second angle is further based on table lookup data.

19. The method as defined in claim 12 , wherein the table lookup data is updated based on at least one of the measured flight metric or the re-measured flight metric.

20. The method as defined in claim 18 , wherein the table lookup data is updated based on the measured flight metric.

21. The method as defined in claim 6 , wherein the control surface includes a first control surface and further including perturbing a second control surface to a second perturbation deflection based on a scaling factor that relates a first degree of perturbation of the second control surface to a second degree of perturbation of the first control surface.

22. The method as defined in claim 4 , wherein the Kalman-filter based method is used to adjust at least one of an uncertainty scaling factor or the perturbation deflection.

23. The method as defined in claim 9 , wherein the Kalman-filter based method is used to adjust at least one of an uncertainty scaling factor or the first angle.

24. The method as defined in claim 13 , wherein calculating the second angle includes using a Kalman-filter based method to estimate a sensitivity of the flight metric.

25. The method as defined in claim 24 , wherein the Kalman-filter method is used to adjust at least one of an uncertainty scaling factor or the first angle.

26. The method as defined in claim 1 , wherein the first deflection is calculated further based on an uncertainty scaling factor.

27. The method as defined in claim 6 , wherein a degree of the induced perturbation of the control surface of the aircraft to the first angle is further calculated based on an uncertainty scaling factor.

28. The method as defined in claim 13 , wherein the calculated deflection of the aircraft control surface is calculated further based on an uncertainty scaling factor.

Assignees

• Boeing Co

Inventors

• Pachikara Abraham J
• Moser Matthew A
• Carpenter Paul H
• Finn Michael R
• Koch Thomas S
• Bieniawski Stefan R
• Whitehead Brian T

Classifications

• B64D45/0005

  Devices specially adapted to indicate the position of a movable element of the aircraft, e.g. landing gear · CPC title

• B64C13/16 Primary

  actuated automatically, e.g. responsive to gust detectors · CPC title

• B64C9/00

  Adjustable control surfaces or members, e.g. rudders (trimming stabilising surfaces B64C5/10) · CPC title

• G05D1/0825

  using mathematical models · CPC title

• B64C9/12 Primary

  surfaces of different type or function being simultaneously adjusted · CPC title