Isolated resonator gyroscope with compact flexures

• US 6,955,084 B2
• Filed: 04/10/2003
• Issued: 10/18/2005
• Est. Priority Date: 08/10/2001
• Status: Active Grant

• Current Assignee: California Institute of Technology, The Boeing Co.
• Original Assignee: California Institute of Technology, The Boeing Co.
• Inventors: Shcheglov, Kirill V., Challoner, A. Dorian
• Primary Examiner(s): MOLLER, RICHARD ALAN
• Application Number:
  US10/410,744
• Publication Number:
  US 20030205087A1
• Time in Patent Office: 922 Days
• Field of Search: 735/040.2, 735/040.3, 735/040.4, 735/041.2, 735/041.6
• US Class Current: 73/504.16
• CPC Class Codes: G01C 19/5712 the devices involving a micromechanical structure
• CPC Class Codes: G01P 2015/084 the mass being suspended at more than one of its sides, e.g. membrane-type suspension, so as to permit multi-axis movement of the mass

Abstract

The present invention discloses a gyroscope comprising an isolated resonator including a post proof mass and counterbalancing plate. One or more double beam flexures each interconnect the counterbalancing plate and the proof mass with a first and a second beam attached to the post proof mass and a third and a fourth beam attached to the counterbalancing plate. A baseplate is affixed to the resonator by the double beam flexures. The counterbalancing plate and the proof mass transfer substantially no net momentum to the baseplate when the resonator is excited.

Claims

1. A resonator gyroscope, comprising:

an isolated resonator including a counterbalancing plate and a proof mass;

one or more double beam flexures each interconnecting the counterbalancing plate and the proof mass with a first and a second beam attached to the proof mass and a third and a fourth beam attached to the counterbalancing plate; and

a baseplate affixed to the resonator by the one or more double beam flexures;

wherein the counterbalancing plate and the proof mass transfer substantially no net momentum to the baseplate when the resonator is excited.

2. The resonator gyroscope of claim 1, wherein the counterbalancing plate and the proof mass each have a center of mass and transverse inertia symmetry about an axis that are substantially coincident and the counterbalancing plate and the proof mass together form two differential rocking modes of vibration transverse to the axis with substantially equal frequencies.

3. The resonator gyroscope of claim 1, wherein the counterbalancing plate has a rocking inertia substantially comparable to that of the proof mass.

4. The resonator gyroscope of claim 1, wherein the proof mass, the counterbalancing plate and the baseplate are machined from silicon.

5. The resonator gyroscope of claim 1, further comprising a mounting plate attached to the baseplate through at least one isolation flexure.

6. The resonator gyroscope of claim 1, wherein the one or more double beam flexures are integral to the counterbalancing plate.

7. The resonator gyroscope of claim 1, wherein at least two of the first, second, third and fourth beams are substantially parallel.

8. The resonator gyroscope of claim 1, wherein at least one of the first, second, third and fourth beams is independently machined to tune the isolated resonator.

9. The resonator gyroscope of claim 1, wherein the one or more double beam flexures each comprise a center beam affixed to the baseplate and the first and the second beam extend from the center beam and the third and the fourth beam extend from the center beam.

10. The resonator gyroscope of claim 9, wherein the center beam is substantially parallel to at least one of the first, second, third and fourth beams.

11. The resonator gyroscope of claim 9, wherein the center beam is affixed to the baseplate through a cross beam.

12. The resonator gyroscope of claim 11, wherein the one or more double beam flexures are each substantially symmetric about the cross beam.

13. The resonator gyroscope of claim 11, wherein the cross beam is affixed to the baseplate by at least a first baseplate post at a first end of the cross beam and a second baseplate post at a second end of the cross beam.

14. The resonator gyroscope of claim 11, wherein the cross beam is affixed to the baseplate through a substantially continuous seam along the cross beam.

15. The resonator gyroscope of claim 1, further comprising sense and drive electrodes affixed to the counterbalancing plate of the resonator.

16. The resonator gyroscope of claim 15, wherein the counterbalancing plate includes an extensive planar region for holding the sense and drive electrodes.

17. The resonator gyroscope of claim 1, wherein the proof mass includes a vertical portion and a central plate portion.

18. The resonator gyroscope of claim 17, wherein the vertical portion comprises a post attached to the central plate portion.

19. The resonator gyroscope of claim 17, wherein the resonator is isolated by changing a length of the vertical portion.

20. The resonator gyroscope of claim 1, wherein the isolated resonator further comprises at least one secondary element for trimming isolation of the resonator.

21. The resonator gyroscope of claim 20, wherein the at least one secondary element provides electrostatic control of a differential rocking mode of the isolated resonator.

22. A method of producing a resonator gyroscope, comprising the steps of:

providing an isolated resonator including a counterbalancing plate and a proof mass;

interconnecting the counterbalancing plate and the proof mass with one or more double beam flexures where each attach to the proof mass with a first and a second beam and each attach to the counterbalancing plate with a third and a fourth beam; and

affixing a baseplate to the resonator by the one or more double beam flexures;

wherein the counterbalancing plate and the proof mass transfer substantially no net momentum to the baseplate when the resonator is excited.

23. The method of claim 22, wherein the counterbalancing plate and the proof mass each have a center of mass and transverse inertia symmetry about an axis that are substantially coincident and the counterbalancing plate and the proof mass together form two differential rocking modes of vibration transverse to the axis with substantially equal frequencies.

24. The method of claim 22, wherein the counterbalancing plate has a rocking inertia substantially comparable to that of the proof mass.

25. The method of claim 22, wherein the proof mass, the counterbalancing plate and the baseplate are machined from silicon.

26. The method of claim 22, further comprising attaching a mounting plate to the baseplate through at least one isolation flexure.

27. The method of claim 22, wherein the one or more double beam flexures are integral to the counterbalancing plate.

28. The method of claim 22, wherein at least two of the first, second, third and fourth beams are substantially parallel.

29. The method of claim 22, wherein at least one of the first, second, third and fourth beams is independently machined to tune the isolated resonator.

30. The method of claim 22, wherein the one or more double beam flexures each comprise a center beam affixed to the baseplate and the first and the second beam extend from the center beam and the third and the fourth beam extend from the center beam.

31. The method of claim 30, wherein the center beam is substantially parallel to at least one of the first, second, third and fourth beams.

32. The method of claim 30, wherein the center beam is affixed to the baseplate through a cross beam.

33. The method of claim 32, wherein the one or more double beam flexures are each substantially symmetric about the cross beam.

34. The method of claim 32, wherein the cross beam is affixed to the baseplate by at least a first baseplate post at a first end of the cross beam and a second baseplate post at a second end of the cross beam.

35. The method of claim 32, wherein the cross beam is affixed to the baseplate through a substantially continuous seam along the cross beam.

36. The method of claim 22, further comprising affixing sense and drive electrodes to the counterbalancing plate of the resonator.

37. The method of claim 36, wherein the counterbalancing plate includes an extensive planar region for holding the sense and drive electrodes.

38. The method of claim 22, wherein the proof mass includes a vertical portion and a central plate portion.

39. The method of claim 38, wherein the vertical portion comprises a post attached to the central plate portion.

40. The method of claim 38, wherein the resonator is isolated by changing a length of the vertical portion.

41. The method of claim 22, further comprising providing at least one secondary element for trimming isolation of the resonator.

42. The method of claim 41, wherein the at least one secondary element provides electrostatic control of a differential rocking mode of the isolated resonator.