Evaluating aileron deflection while an unmanned aerial vehicle is in flight

• US 9,284,043 B2
• Filed: 11/21/2013
• Issued: 03/15/2016
• Est. Priority Date: 11/21/2013
• Status: Active Grant

• Current Assignee: Textron Systems Corporation (Textron Inc)
• Original Assignee: AAI Corporation (Textron Inc)
• Inventors: Barbour, James M.
• Primary Examiner(s): Jabr, Fadey
• Assistant Examiner(s): SHUDY, ANGELINA M
• Application Number:
  US14/086,370
• Publication Number:
  US 20150142223A1
• Time in Patent Office: 845 Days
• Field of Search: 701/3, 701/4, 701/14, 702/85, 702/94, 702/95, 702/107, 702/163, 340/945, 340/963, 340/964, 244/1, 244/75.1, 244/158
• US Class Current: 1/1
• CPC Class Codes: B64C 13/16 actuated automatically, e.g. responsive to gust detectors
• CPC Class Codes: B64U 2201/10 autonomous, i.e. by navigating independently from ground or air stations, e.g. by using inertial navigation systems [INS]
• CPC Class Codes: G05D 1/0055 with safety arrangements

Abstract

A technique is directed to operating a UAV. The technique involves launching (or guiding) the UAV into flight. The technique further involves performing a series of aileron (or other control surface) deflection evaluations while the UAV is in flight. The technique further involves performing a UAV remedial operation in response to the series of aileron deflection evaluations indicating abnormal aileron behavior, e.g., the UAV can send a warning message to a ground control station (GCS), land the UAV at a target location, deploy a chute, and so on. Such operation enables detection of an unexpected change in the UAV'"'"'s center of gravity, e.g., due to a blocked fuel bladder connection, icing on one side of the UAV, mechanical failure of an aileron, etc.

Claims

1. A method of operating an unmanned aerial vehicle (UAV), the method comprising:

launching, by processing circuitry, the UAV into flight;

performing, by the processing circuitry, a series of control surface deflection evaluations while the UAV is in flight; and

performing, by the processing circuitry, a UAV remedial operation in response to the series of control surface deflection evaluations indicating abnormal control surface deflection behavior;

wherein performing the series of control surface deflection evaluations includes;

while a set of ailerons of the UAV operate normally to compensate for a shift in the center of gravity of the UAV, identifying an UAV weight imbalance situation based on deflection by the set of ailerons; and

wherein identifying the UAV weight imbalance situation includes;

while the set of ailerons of the UAV operate normally to compensate for the shift in the center of gravity of the UAV, detecting (i) gradually increasing deflection of a first aileron in a first deflection direction over time and (ii) gradually increasing deflection of a second aileron in a second deflection direction over time, the first deflection direction being opposite the second deflection direction, to identify occurrence of a weight imbalance condition.

2. The method as in claim 1 wherein detecting the gradually increasing deflections of the first and second ailerons includes:

identifying a set of initial aileron positions,

comparing a set of average aileron positions to the set of initial aileron positions, and

providing a series of evaluation results indicating whether the UAV has encountered abnormal aileron deflection behavior.

3. The method as in claim 2 wherein identifying the set of initial aileron positions includes:

identifying, as one of the initial aileron positions, a first neutral position for a first aileron of the UAV, and

identifying, as another of the initial aileron positions, a second neutral position for a second aileron of the UAV.

4. The method as in claim 3 wherein comparing the set of average aileron positions to the set of initial aileron positions includes:

maintaining a first aileron position average for the first aileron, the first aileron position average representing an average amount of angular deflection of the first aileron from the first neutral position, and

maintaining a second aileron position average for the second aileron, the second aileron position average representing an average amount of angular deflection of the second aileron from the second neutral position.

5. The method as in claim 4 wherein providing the series of evaluation results includes:

outputting normal evaluation results indicating normal aileron deflection behavior when each aileron position average remains below a predefined aileron position average threshold, and

outputting abnormal evaluation results indicating abnormal aileron deflection behavior when at least one aileron position average exceeds the predefined aileron position average threshold.

6. The method as in claim 4 wherein providing the series of evaluation results includes:

outputting normal evaluation results indicating normal aileron deflection behavior when a sum of the aileron position averages remains below a predefined aileron position average threshold, and

outputting abnormal evaluation results indicating abnormal aileron deflection behavior when the sum of the aileron position averages exceeds the predefined aileron position average threshold.

7. The method as in claim 3 wherein launching the UAV into flight includes:

flying the UAV in a straight-line level pattern during an auto-launch time period following takeoff.

8. The method as in claim 7 wherein identifying the set of initial aileron positions includes:

recording, as a first neutral position for the first aileron, a current position of the first aileron while the UAV flies in the straight-line level pattern during the auto-launch time period, and

recording, as a second neutral position for the second aileron, a current position of the second aileron while the UAV flies in the straight-line level pattern during the auto-launch time period.

9. The method as in claim 3 wherein performing the UAV remedial operation includes:

sending a warning message to a ground control station indicating that the UAV has encountered a weight imbalance condition.

10. The method as in claim 3 wherein performing the UAV remedial operation includes:

performing a fuel assessment operation which provides a result indicating whether a single operable fuel bladder of the UAV has enough fuel for the UAV to land at the designated target location.

11. The method as in claim 10 wherein performing the UAV remedial operation further includes:

flying the UAV to the designated target location and landing the UAV at the designated target location when the result of the fuel assessment operation indicates that the single operable fuel bladder of the UAV has enough fuel for the UAV to land at the designated target location, and

deploying a chute of the UAV when the result of the fuel assessment operation indicates that the single operable fuel bladder of the UAV does not have enough fuel for the UAV to land at the designated target location.

12. The method as in claim 3 wherein performing the UAV remedial operation includes:

performing a fuel assessment operation which provides a result indicating whether a single operable fuel bladder of the UAV has enough fuel for the UAV to complete an initially assigned mission.

13. The method as in claim 12 wherein performing the UAV remedial operation further includes:

completing the initially assigned mission when the result of the fuel assessment operation indicates that the single operable fuel bladder of the UAV has enough fuel for the UAV to complete the initially assigned mission, and

aborting the initially assigned mission when the result of the fuel assessment operation indicates that the single operable fuel bladder of the UAV does not have enough fuel for the UAV to complete the initially assigned mission.

14. The method as in claim 2 wherein performing the series of control surface deflection evaluations includes:

providing compensation input to the series of control surface deflection evaluations in response to release of ammunition from the UAV.

15. The method as in claim 1 wherein detecting the gradually increasing deflections of the first and second ailerons includes:

tracking an average position of the first aileron and comparing a current position of the first aileron to the average position of the first aileron, and

tracking an average position of the second aileron and comparing a current position of the second aileron to the average position of the second aileron.

16. The method as in claim 1 wherein detecting the gradually increasing deflections of the first and second ailerons includes:

tracking a first deflection rate of change by the first aileron exceeds a first deflection rate threshold, and

tracking a second deflection rate of change by the second aileron exceeds a second deflection rate threshold.

17. An unmanned aerial vehicle, comprising:

an unmanned aerial vehicle (UAV) frame;

a set of ailerons supported by the UAV frame; and

a controller supported by the UAV frame and in operable communication with the ailerons, the controller being constructed and arranged to;

while the UAV is in flight, perform a series of aileron deflection evaluations, and

perform a UAV remedial operation in response to the series of aileron deflection evaluations indicating abnormal aileron behavior;

wherein the controller, when performing the series of aileron deflection evaluations includes;

while the set of ailerons of the UAV operate normally to compensate for a shift in the center of gravity of the UAV, identifying an UAV weight imbalance situation based on deflection by the set of ailerons; and

wherein identifying the UAV weight imbalance situation includes;

while the set of ailerons of the UAV operate normally to compensate for the shift in the center of gravity of the UAV, detecting (i) gradually increasing deflection of a first aileron in a first deflection direction over time and (ii) gradually increasing deflection of a second aileron in a second deflection direction over time, the first deflection direction being opposite the second deflection direction, to identify occurrence of a weight imbalance condition.

18. The unmanned aerial vehicle as in claim 17 wherein the controller, when detecting the gradually increasing deflections of the first and second ailerons, is constructed and arranged to:

identify a set of initial aileron positions,

compare a set of average aileron positions to the set of initial aileron positions, and

provide a series of evaluation results indicating whether the UAV has encountered abnormal aileron deflection behavior.

19. The unmanned aerial vehicle as in claim 18 wherein the controller, when identifying the set of initial aileron positions, is constructed and arranged to:

identify, as one of the initial aileron positions, a first neutral position for a first aileron of the UAV, and

identify, as another of the initial aileron positions, a second neutral position for a second aileron of the UAV.

20. The unmanned aerial vehicle as in claim 19 wherein the controller, when comparing the set of average aileron positions to the set of initial aileron positions, is constructed and arranged to:

maintain a first aileron position average for the first aileron, the first aileron position average representing an average amount of angular deflection of the first aileron from the first neutral position, and

maintain a second aileron position average for the second aileron, the second aileron position average representing an average amount of angular deflection of the second aileron from the second neutral position.

21. The unmanned aerial vehicle in claim 20 wherein the controller, when launching the UAV into flight, is constructed and arranged to fly the UAV in a straight-line level pattern during an auto-launch time period following takeoff;

and

wherein the controller, when identifying the set of initial aileron positions, is constructed and arranged to (i) record, as a first neutral position for the first aileron, a current position of the first aileron while the UAV flies in the straight-line level pattern during the auto-launch time period, and (ii) record, as a second neutral position for the second aileron, a current position of the second aileron while the UAV flies in the straight-line level pattern during the auto-launch time period.

22. A computer program product having a non-transitory computer readable medium which stores a set of instructions to operate an unmanned aerial vehicle (UAV), the set of instructions, when carried out by computerized circuitry, causing the computerized circuitry to perform a method of:

launching the UAV into flight;

while the UAV is in flight, performing a series of aileron deflection evaluations; and

performing a UAV remedial operation in response to the series of aileron deflection evaluations indicating abnormal aileron behavior;

wherein performing the series of aileron deflection evaluations includes;

while a set of ailerons of the UAV operate normally to compensate for a shift in the center of gravity of the UAV, identifying an UAV weight imbalance situation based on deflection by the set of ailerons; and

wherein identifying the UAV weight imbalance situation includes;

while the set of ailerons of the UAV operate normally to compensate for the shift in the center of gravity of the UAV, detecting (i) gradually increasing deflection of a first aileron in a first deflection direction over time and (ii) gradually increasing deflection of a second aileron in a second deflection direction over time, the first deflection direction being opposite the second deflection direction, to identify occurrence of a weight imbalance condition.

23. The computer program product as in claim 22 wherein detecting the gradually increasing deflections of the first and second ailerons includes:

tracking an average position of the first aileron and comparing a current position of the first aileron to the average position of the first aileron, and

tracking an average position of the second aileron and comparing a current position of the second aileron to the average position of the second aileron.

24. The computer program product as in claim 22 wherein detecting the gradually increasing deflections of the first and second ailerons includes:

tracking a first deflection rate of change by the first aileron exceeds a first deflection rate threshold, and

tracking a second deflection rate of change by the second aileron exceeds a second deflection rate threshold.