Cyclic minimizer through alignment of the center of gravity and direction of flight vectors

• US 5,676,334 A
• Filed: 12/21/1995
• Issued: 10/14/1997
• Est. Priority Date: 12/21/1995
• Status: Expired due to Fees

• Current Assignee: Sikorsky Aircraft Corporation (Martin Marietta Corporation)
• Original Assignee: Sikorsky Aircraft Corporation (Martin Marietta Corporation)
• Inventors: Cotton, Bryan S., Thornberg, Christopher A.
• Primary Examiner(s): Grant, William
• Application Number:
  US08/576,603
• Time in Patent Office: 663 Days
• Field of Search: 244/17.11, 244/17.13, 244/17.19, 244/17.23, 244/17.25, 244/175, 244/190, 244/23 C, 244/12.2
• US Class Current: 244/17.13
• CPC Class Codes: B64C 27/54 Mechanisms for controlling blade adjustment or movement relative to rotor head, e.g. lag-lead movement
• CPC Class Codes: G05D 1/0816 to ensure stability

Abstract

Apparatus and method for controlling an unmanned generally aerodynamically symmetric aircraft includes detecting the presence of misalignment between the horizontal component of the center of gravity vector and the horizontal component of the direction of flight vector and further includes rotating the aircraft to align the horizontal components of the vectors.

Claims

1. Apparatus for controlling an unmanned generally aerodynamically symmetric aircraft having a geometric center, a center of gravity, and a direction of flight, the apparatus useful to align the horizontal component of a center of gravity vector with the horizontal component of a direction of flight vector, the center of gravity vector represented by a line from the geometric center to the center of gravity, and the direction of flight vector represented by a line from the geometric center in the direction of flight, wherein the aircraft can be rotated about its geometric center, the apparatus comprising:

detection means for detecting the presence of misalignment between the horizontal components of the center of gravity and direction of flight vectors, and for providing a rotation signal indicative of the desired rotation of the aircraft to align the horizontal components of the center of gravity and direction of flight vectors; and

rotation means, responsive to said detection means, for providing, in the presence of said rotation signal, rotation of the unmanned generally aerodynamically symmetric aircraft about its geometric center to align the horizontal components of the center of gravity and direction of flight vectors.

2. The apparatus of claim 1 wherein said rotation means comprises a re-direct transform, responsive to a first set of at least one command signal and said detection means, for providing re-direction of said first set of at least one command signal in a manner proportionate to the magnitude of said rotation signal.

3. The apparatus of claim 2 wherein said first set of at least one re-directed command signal is presented to a control portion which produces at least one control signal;

and

said detection means comprises a direction of flight transform, responsive to said at least one control signal, and said detection means rotation signal, for detecting the presence of misalignment between the horizontal components of the center of gravity and direction of flight vectors.

4. The apparatus of claim 3 wherein said rotation means comprises a summation, responsive to a second set of at least one command signal and said detection means, for providing re-direction of said second set of at least one command signal, said re-direction produced by summing each of said second set of at least one command signal with an amount generally proportionate to the magnitude of said rotation signal.

5. The apparatus of claim 4 wherein said at least one control signal comprises pitch and roll cyclic command signals, said first set of at least one command signal comprises pitch and roll attitude command signals, and said second set of at least one command signal comprises a heading command signal.

6. The apparatus of claim 1 wherein said detection means and said rotation means comprise a software program executed by a computer.

7. The apparatus of claim 1 wherein said detection means comprises a direction of flight transform, responsive to said detection means rotation signal, for detecting the presence of misalignment between the horizontal components of the center of gravity and direction of flight vectors.

8. The apparatus of claim 1 wherein said rotation signal has a magnitude, and said magnitude is modified by an amount that is generally proportional to the magnitude of the misalignment between the horizontal components of the center of gravity and direction of flight vectors.

9. The apparatus of claim 1 wherein said rotation means comprises a summation, responsive to a second set of at least one command signal and said detection means, for providing re-direction of said second set of at least one command signal, said re-direction produced by summing each of said second set of at least one command signal with an amount generally proportional to the magnitude of said rotation signal.

10. Apparatus for controlling an unmanned generally aerodynamically symmetric rotary wing aircraft having a geometric center, a center of gravity, and a direction of flight, the apparatus useful to align the horizontal component of a center of gravity vector with the horizontal component of a direction of flight vector, the center of gravity vector represented by a line from the geometric center to the center of gravity, and the direction of flight vector represented by a line from the geometric center in the direction of flight, wherein the aircraft can be rotated in its yaw axis about its geometric center, the apparatus comprising:

detection means for detecting the presence of misalignment between the horizontal components of the center of gravity and direction of flight vectors, and for providing a rotation signal indicative of the desired rotation of the aircraft to align the horizontal components of the center of gravity and direction of flight vectors; and

rotation means, responsive to said detection means, for providing, in the presence of said rotation signal, rotation of the unmanned generally aerodynamically symmetric rotary wing aircraft about its geometric center to align the horizontal componets of the center of gravity and direction of flight vectors.

11. The apparatus of claim 10 wherein said rotation means comprises a re-direct transform, responsive to a pitch axis command signal, a roll axis command signal and said detection means, for providing re-direction of said pitch and roll axis command signals in a manner proportionate to the magnitude of said rotation signal.

12. The apparatus of claim 11 wherein said re-directed pitch and roll axis command signals are presented to a control portion which produces at least one control signal;

and

said detection means comprises a direction of flight transform, responsive to said at least one control signal, and said detection means rotation signal, for detecting the presence of misalignment between the horizontal components of the center of gravity and direction of flight vector.

13. The apparatus of claim 12 wherein said at least one control signal comprises pitch and roll cyclic command signals.

14. The apparatus of claim 13 wherein said pitch and roll axis command signals comprise pitch and roll attitude command signals, and said yaw axis command signal comprises a heading command signal.

15. The apparatus of claim 12 wherein said rotation means comprises a summation, responsive to a yaw axis command signal and said detection means, for providing re-direction of said yaw axis command signal, said re-direction produced by summing said yaw command signal with an amount generally proportionate to the magnitude of said rotation signal.

16. The apparatus of claim 10 wherein said detection means and said rotation means comprise a software program executed by a computer.

17. The apparatus of claim 10 wherein said detection means comprises a direction of flight transform, responsive to said detection means rotation signal, for detecting the presence of misalignment between the horizontal components of the center of gravity and direction of flight vectors.

18. The apparatus of claim 10 wherein said rotation signal has a magnitude, and said magnitude is modified by an amount that is generally proportional to the magnitude of the misalignment between the horizontal components of the center of gravity and direction of flight vectors.

19. The apparatus of claim 10 wherein said rotation means comprises a summation, responsive to a yaw axis command signal and said detection means, for providing re-direction of said yaw axis command signal, said re-direction produced by summing said yaw axis command signal with an amount generally proportional to the magnitude of said rotation signal.

20. A method for controlling an unmanned generally aerodynamically symmetric aircraft having a geometric center, a center of gravity, and a direction of flight, the method useful to align the horizontal component of a center of gravity vector with the horizontal component of a direction of flight vector, the center of gravity vector represented by a line from the geometric center to the center of gravity, and the direction of flight vector represented by a line from the geometric center in the direction of flight, wherein the aircraft can be rotated about its geometric center, the method comprising the steps of:

detecting the presence of misalignment between the horizontal components of the center of gravity vector and the direction of flight vector, and providing a rotation signal indicative of the desired rotation of the aircraft to align the horizontal components of the center of gravity and direction of flight vectors; and

rotating the unmanned generally aerodynamically symmetric aircraft about its geometric center, in response to said rotation signal, to align the horizontal components of the center of gravity and direction of flight vectors.

21. The method of claim 20 wherein said step of rotating further comprises the step of transforming a first set of at least one command signal, in a manner proportionate to the magnitude of said rotation signal, to produce a first set of at least one re-directed command signal.

22. The method of claim 21 wherein said step of rotating further comprises the step of presenting said first set of at least one re-directed command signal to a control portion which produces at least one control signal;

and

said step of detecting further comprises the step of transforming said at least one control signal to produce a misalignment signal indicative of the presence of misalignment between the horizontal components of the center of gravity and direction of flight vectors.

23. The method of claim 22 wherein said step of rotating further comprises summing a second set of at least one command signal with an amount generally proportional to the magnitude of said rotation signal to produce a second set of at least one re-directed command signal.

24. The method of claim 23 wherein said at least one control signal comprises pitch and roll cyclic command signals, said first set of at least one command signal comprises pitch and roll attitude command signals, and said second set of at least one command signal comprises a heading command signal.

25. The method of claim 20 wherein said step of detecting and said step of rotating further comprise the use of a software program executed by a computer.

26. The method of claim 20 wherein said step of detecting further comprises the step of transforming at least one control signal to produce a misalignment signal indicative of the presence of misalignment between the horizontal components of the center of gravity and direction of flight vectors.

27. The method of claim 20 wherein said rotation signal has a magnitude, and said magnitude is modified by an amount that is generally proportional to the magnitude of the misalignment between the horizontal components of the center of gravity and direction of flight vectors.

28. The method of claim 20 wherein said step of rotating further comprises the step of summing a second set of at least one command signal with an amount generally proportionate to the magnitude of said rotation signal, to provide a second set of at least one re-directed command signal.

29. A method for controlling an unmanned generally aerodynamically symmetric rotary wing aircraft having a geometric center, a center of gravity, and a direction of flight, the method useful to align the horizontal component of a center of gravity vector with the horizontal component of a direction of flight vector, the center of gravity vector represented by a line from the geometric center to the center of gravity, and the direction of flight vector represented by a line from the geometric center in the direction of flight, wherein the aircraft can be rotated in its yaw axis about its geometric center, the method comprising the steps of:

detecting the presence of misalignment between the horizontal components of the center of gravity vector and the direction of flight vector and, providing a rotation signal indicative of the desired rotation of the aircraft to align the horizontal components of the center of gravity and direction of flight vectors; and

rotating the unmanned generally aerodynamically symmetric rotary wing aircraft about its geometric center, in response to said rotation signal, to align the horizontal components of the center of gravity and direction of flight vectors.

30. The method of claim 29 wherein said step of rotating further comprises the step of transforming a pitch axis command signal and a roll axis command signal, in a manner proportionate to the magnitude of said rotation signal, to produce re-directed pitch axis and roll axis command signals.

31. The method of claim 30 wherein said step of rotating further comprises the step of presenting said re-directed pitch and roll axis command signals to a control portion which produces at least one control signal;

and

said step of detecting further comprises the step of transforming said at least one control signal to produce a misalignment signal indicative of the presence of misalignment between the horizontal components of the center of gravity and direction of flight vectors.

32. The method of claim 31 wherein said step of rotating further comprises summing a yaw axis command signal with an amount generally proportional to the magnitude of said rotation signal to produce a re-directed yaw axis command signal.

33. The method of claim 32 wherein said at least one control signal comprises pitch and roll cyclic command signals.

34. The method of claim 31 wherein said pitch and roll axis command signals comprise pitch and roll attitude command signals, and said yaw axis command signal comprises a heading command signal.

35. The method of claim 29 wherein said step of detecting and said step of rotating further comprise the use of a computer executing a software program.

36. The method of claim 29 wherein said step of detecting further comprises the step of transforming at least one control signal to produce a misalignment signal indicative of the presence of misalignment between the horizontal components of the center of gravity and direction of flight vectors.

37. The method of claim 29 wherein said rotation signal has a magnitude, and said magnitude is modified by an amount that is generally proportional to the magnitude of the misalignment between the horizontal components of the center of gravity and direction of flight vectors.

38. The method of claim 29 wherein said step of rotating further comprises the step of summing a yaw axis command signal with an amount generally proportionate to the magnitude of said rotation signal, to provide a re-directed yaw axis command signal.