Isolated resonator gyroscope with a drive and sense plate

• US 20030150267A1
• Filed: 02/20/2003
• Published: 08/14/2003
• Est. Priority Date: 08/10/2001
• Status: Active Grant

• Current Assignee: California Institute of Technology, The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Shcheglov, Kirill V., Challoner, A. Dorian
• Granted Patent: US 7,017,410 B2
• Time in Patent Office: Days
• US Class Current: 73/504.02
• CPC Class Codes: G01C 19/5656 the devices involving a micromechanical structure
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis
• 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
• CPC Class Codes: Y10T 29/49007 Indicating transducer

Abstract

The present invention discloses a resonator gyroscope comprising a vibrationally isolated resonator including a proof mass, a counterbalancing plate having an extensive planar region, and one or more flexures interconnecting the proof mass and counterbalancing plate. A baseplate is affixed to the resonator by the one or more flexures and sense and drive electrodes are affixed to the baseplate proximate to the extensive planar region of the counterbalancing plate for exciting the resonator and sensing movement of the gyroscope. The isolated resonator transfers substantially no net momentum to the baseplate when the resonator is excited.

Claims

1. A resonator gyroscope, comprising:

an isolated resonator including;

a proof mass;

a counterbalancing plate having an extensive planar region; and

one or more flexures interconnecting the proof mass and counterbalancing plate;

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

drive and sense electrodes affixed to the baseplate proximate to the extensive planar region of the counterbalancing plate for exciting the resonator and sensing movement of the gyroscope;

wherein the isolated resonator transfers substantially no net momentum to the baseplate when the resonator is excited.

2. The resonator gyroscope of claim 1, wherein the proof mass and counterbalancing plate each have a center of mass and transverse inertia symmetry about an axis that are substantially coincident and the proof mass and counterbalancing plate 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 sense electrodes are disposed around the periphery of the counterbalancing plate.

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

5. The resonator gyroscope of claim 1, wherein the baseplate is rigid.

6. The resonator gyroscope of claim 1, wherein the baseplate is flexible.

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

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

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

10. The resonator gyroscope of claim 1, wherein each of the one or more flexures is a beam flexure attached to the proof mass at a first end and the counterbalancing plate at a second end.

11. The resonator gyroscope of claim 10, wherein each beam flexure is attached to the baseplate off center and nearer to the proof mass than an attachment point to the counterbalancing plate.

12. The resonator gyroscope of claim 1, wherein the proof mass comprises a vertical portion.

13. The resonator gyroscope of claim 12, wherein the one or more flexures are integral to the central plate portion.

14. The resonator gyroscope of claim 12, wherein the central plate portion, one or more flexures and the counterbalancing plate are produced by through-etching a precision-polished silicon wafer.

15. The resonator gyroscope of claim 12, wherein the vertical portion is a separate element bonded to the central plate portion.

16. The resonator gyroscope of claim 15, wherein the separate element comprises sapphire.

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

providing an isolated resonator including;

a proof mass;

a counterbalancing plate having an extensive planar region; and

one or more flexures interconnecting the proof mass and

counterbalancing plate;

affixing drive and sense electrodes to the baseplate; and

affixing the resonator to a baseplate by the one or more flexures such that the drive and sense electrodes are disposed proximate to the extensive planar region of the counterbalancing plate;

wherein the isolated resonator transfers substantially no net momentum to the baseplate when the resonator is excited.

18. The method of claim 17, wherein the proof mass and counterbalancing plate each have a center of mass and transverse inertia symmetry about an axis that are substantially coincident and the proof mass and counterbalancing plate together form two differential rocking modes of vibration transverse to the axis with substantially equal frequencies.

19. The method of claim 17, wherein the sense electrodes are disposed around the periphery of the counterbalancing plate.

20. The method of claim 17, further comprising providing a mounting frame attached to the baseplate through at least one isolation flexure.

21. The method of claim 17, wherein the baseplate is rigid.

22. The method of claim 17, wherein the baseplate is flexible.

23. The method of claim 17, wherein the counterbalancing plate has a rocking inertia substantially comparable to that of the proof mass.

24. The method of claim 17, wherein the one or more flexures are produced integral to the counterbalancing plate.

25. The method of claim 17, wherein the steps of producing and affixing comprise machining the proof mass, counterbalancing plate and baseplate from silicon.

26. The method of claim 17, wherein each of the one or more flexures is a beam flexure attached to the proof mass at a first end and the counterbalancing plate at a second end.

27. The method of claim 26, wherein each beam flexure is attached to the baseplate off center and nearer to the proof mass than an attachment point to the counterbalancing plate.

28. The method of claim 17, wherein the proof mass comprises a vertical portion.

29. The method of claim 28, wherein the one or more flexures are integral to the central plate portion.

30. The method of claim 28, wherein the central plate portion, one or more flexures and the counterbalancing plate are produced by through etching a precision polished silicon wafer.

31. The method of claim 28, wherein the vertical portion is a separate element from the central plate portion and the step of producing the proof mass comprises bonding the vertical portion to the central plate portion.

32. The method of claim 31, wherein the separate element comprises sapphire.