Actuation response oscillation detection monitor

• US 7,567,862 B2
• Filed: 08/14/2007
• Issued: 07/28/2009
• Est. Priority Date: 08/14/2007
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Pelton, David Andrew, Slaugh, Dallin Brent, Pabisz, Michael Joseph
• Primary Examiner(s): Camby; Richard M.
• Application Number:
  US11/838,525
• Publication Number:
  US 20090048689A1
• Time in Patent Office: 714 Days
• Field of Search: 701/29, 701/33, 701/34, 701/35, 701/36, 701/3, 701/4, 701/9, 244/75.1, 244/76.A, 244/76.R, 244/227
• US Class Current: 701/33
• CPC Class Codes: B64C 13/0423 yokes or steering wheels for primary flight controls
• CPC Class Codes: B64C 13/0425 for actuating trailing or leading edge flaps, air brakes or spoilers
• CPC Class Codes: B64D 45/0005 Devices specially adapted to indicate the position of a movable element of the aircraft, e.g. landing gear
• CPC Class Codes: G05B 23/0235 based on a comparison with predetermined threshold or range, e.g. "classical methods", carried out during normal operation; threshold adaptation or choice; when or how to compare with the threshold

Abstract

A method, apparatus, and computer usable program code for monitoring an actuator for a control surface on an aircraft. In one advantageous embodiment, an error signal generated is received in response to sending a command to the actuator to move the control surface on the aircraft. Responsive to receiving the error signal, an amplitude and a frequency are identified for the error signal. A determination is made as to whether the amplitude exceeds a set of amplitude limits for the frequency, wherein each amplitude in the set of amplitude limits is associated with a requirement in a set of requirements. An exceedance count is incremented for each requirement in the set of requirements in which an associated amplitude limit has been exceeded by the amplitude to form an updated set of exceedance counts. A fault indication is generated if any exceedance count in the updated set of exceedance counts is greater than a threshold.

Claims

1. A method for monitoring an actuator for a control surface on an aircraft, the method comprising:

receiving an error signal generated in response to sending a command to the actuator to move the control surface on the aircraft;

responsive to receiving the error signal, identifying an amplitude and a frequency for the error signal;

determining whether the amplitude exceeds a set of amplitude limits for the frequency, wherein each amplitude in the set of amplitude limits is associated with a requirement in a set of requirements;

incrementing an exceedance count for each requirement in the set of requirements in which an associated amplitude limit has been exceeded by the amplitude to form an updated set of exceedance counts; and

generating a fault indication if any exceedance count in the updated set of exceedance counts is greater than a threshold.

2. The method of claim 1, wherein the frequency for the error signal is an averaged frequency.

3. The method of claim 1 further comprising:

responsive to a generation of the fault indication, preventing use of the actuator to control the control surface.

4. The method of claim 3 further comprising:

responsive to the generation of the fault indication, using a second actuator to control the control surface.

5. The method of claim 1 further comprising:

sending the command to the actuator to move to a commanded position;

receiving feedback identifying an actual position for the actuator in response to the command; and

generating an error signal from a difference between the commanded position and the actual position to generate the error signal.

6. The method of claim 5, wherein the generating step comprises:

generating an initial error signal from the difference between the commanded position and the actual position; and

filtering the initial error signal to generate the error signal.

7. The method of claim 1, wherein the control surface is selected from a group comprising an aileron, a spoiler, a elevator, a rudder, or a flaperon.

8. The method of claim 1, wherein the set of amplitude limits for the frequency are identified from a set of tables containing amplitude limits for different frequencies.

9. The method of claim 1, wherein the method is implemented in one of hardware, software, or hardware and software.

10. A method for monitoring oscillations, the method comprising:

receiving an error signal from sending a command to a part controlled by an actuator;

identifying a frequency and an amplitude for the error signal;

identifying a current number of times any amplitude limit has been exceeded by the amplitude for the error signal, wherein the amplitude limit is identified by the frequency of the error signal; and

generating a fault indication if the current number of times exceeds a threshold.

11. The method of claim 10, wherein the part is a control surface on an aircraft.

12. The method of claim 11, wherein the control surface is selected from a group comprising an aileron, a spoiler, a elevator, a rudder, or a flaperon.

13. The method of claim 10 further comprising:

responsive to a generation of the fault indication, preventing use of the actuator to control the part.

14. The method of claim 13 further comprising:

responsive to the generation of the fault indication, using a second actuator to control the part.

15. The method of claim 10 further comprising:

initiating a corrective action when the fault indication is generated.

16. The method of claim 10, wherein the control surface is located on one of an aircraft, a spacecraft, a submarine, and a race car.

17. An apparatus comprising:

an electro-hydraulic actuator capable of receiving a command to change a position of a control surface to a command position and controlling the surface using received commands; and

a health monitoring system capable of receiving data regarding the commanded position and an actual position for the electro-hydraulic actuator, generating an error signal from a difference between the commanded position and the actual position, calculating a frequency and an amplitude for the error signal, comparing the amplitude to a threshold that is selected based on the frequency, and selectively generating a fault indication when the threshold is exceeded.

18. The apparatus of claim 17, wherein the health monitoring system determines whether a number of times thresholds based on frequencies of errors signals have been exceeded exceed a limit to selectively generate the fault.

19. The apparatus of claim 17, wherein the health monitoring system is capable of initiating a corrective action if the fault indication is generated.

20. The apparatus of claim 19, wherein the corrective action is to use a backup actuator in place of the electro-hydraulic actuator to change the position of the control surface.