VIBRATORY GYROSCOPE WITH PARASITIC MODE DAMPING

• US 20080148846A1
• Filed: 12/22/2006
• Published: 06/26/2008
• Est. Priority Date: 12/22/2006
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Whelan, David, Challoner, A. Dorian
• Granted Patent: US 7,493,814 B2
• Time in Patent Office: Days
• US Class Current: 73/504.12
• CPC Class Codes: G01C 19/5684 the devices involving a micromechanical structure

Abstract

Operation of a planar resonator gyroscope with in-plane parasitic modes of vibration to obtain improved performance is disclosed. A planar resonator gyroscope, such as a disc resonator gyroscope, may be operated with embedded electrodes. The embedded electrodes may be disposed adjacent to the planar resonator and proximate to one or more anti-nodes of a parasitic vibration mode. A sensed amplitude of the parasitic mode is applied in differential signals used to operate the gyroscope. A feedback controller for damping the parasitic mode applies a drive voltage generated from the proportional voltage to one or more drive electrodes adjacent to the planar resonator disposed proximate to one or more anti-nodes of the parasitic vibration mode of the planar resonator. Parasitic in-plane modes may be thus damped in operating the gyroscope with active damping applied through an analog operational amplifier or digital feedback.

Claims

1. A method of operating a planar resonator, comprising the steps of:

sensing an amplitude of a parasitic vibration mode of a planar resonator with one or more sense electrodes of a plurality of capacitive electrodes adjacent to the planar resonator disposed proximate to one or more anti-nodes of the parasitic vibration mode of the planar resonator;

generating a proportional voltage to the amplitude of the parasitic vibration mode; and

damping the parasitic mode by applying a drive voltage generated from the proportional voltage to at least one or more drive electrodes of the plurality of capacitive electrodes adjacent to the planar resonator disposed proximate to the one or more anti-nodes of the parasitic vibration mode of the planar resonator.

2. The method of claim 1, wherein the planar resonator comprises a disc resonator.

3. The method of claim 2, wherein the disc resonator comprises a centrally mounted and circumferentially slotted disc and the plurality of capacitive electrodes comprise embedded electrodes within the disc resonator.

4. The method of claim 3, wherein the one or more sense electrodes are peripheral to the one or more drive electrodes around the disc resonator.

5. The method of claim 1, wherein the planar resonator is operated as a gyroscope to measure rotation of the planar resonator.

6. The method of claim 1, wherein the one or more sense electrodes comprise a plurality of partitioned sense electrodes to provide a differential sense signal to sense the amplitude of the parasitic vibration mode.

7. The method of claim 6, wherein the planar resonator comprises disc resonator having a central mounting point and the plurality of partitioned sense electrodes to sense the amplitude of the parasitic vibration mode are partitioned between one or more inboard sense electrodes and one or more outboard sense electrodes.

8. The method of claim 1, wherein the proportional voltage is generated with an analog control circuit.

9. The method of claim 1, wherein the proportional voltage is generated with a digital control circuit.

10. The method of claim 1, wherein applying the drive voltage comprises actively controlling a common mode position and velocity using wideband DC capacitive sensing.

11. A sensor, comprising:

a planar resonator;

a plurality of capacitive electrodes disposed adjacent to the planar resonator and proximate to one or more anti-nodes of the parasitic vibration mode of the planar resonator, the plurality of capacitive electrodes including one or more sense electrodes for sensing an amplitude of a parasitic vibration mode of the planar resonator;

a sensing circuit for generating a proportional voltage to the amplitude of the parasitic vibration mode; and

a feedback controller for damping the parasitic mode by applying a drive voltage generated from the proportional voltage to at least one or more drive electrodes of the plurality of capacitive electrodes adjacent to the planar resonator disposed proximate to the one or more anti-nodes of the parasitic vibration mode of the planar resonator.

12. The sensor of claim 11, wherein the planar resonator comprises a disc resonator.

13. The sensor of claim 12, wherein the disc resonator comprises a centrally mounted and circumferentially slotted disc and the plurality of capacitive electrodes comprise embedded electrodes within the disc resonator.

14. The sensor of claim 13, wherein the one or more sense electrodes are peripheral to the one or more drive electrodes around the disc resonator.

15. The sensor of claim 11, wherein the planar resonator is operated as a gyroscope to measure rotation of the planar resonator.

16. The sensor of claim 11, wherein the one or more sense electrodes comprise a plurality of partitioned sense electrodes to provide a differential sense signal to sense the amplitude of the parasitic vibration mode.

17. The sensor of claim 16, wherein the planar resonator comprises disc resonator having a central mounting point and the plurality of partitioned sense electrodes to sense the amplitude of the parasitic vibration mode are partitioned between one or more inboard sense electrodes and one or more outboard sense electrodes.

18. The sensor of claim 11, wherein the proportional voltage is generated with an analog control circuit.

19. The sensor of claim 11, wherein the proportional voltage is generated with a digital control circuit.

20. The sensor of claim 11, wherein applying the drive voltage comprises actively controlling a common mode position and velocity using wideband DC capacitive sensing.

21. A gyroscope, comprising:

a planar resonator means for sensing a rotation having at least one set of drive electrodes partitioned into an opposing drive pair on opposite sides of a central mounting point of a planar resonator and at least one set of sense electrodes partitioned into an opposing sense pair on opposite sides of the central mounting point of the planar resonator; and

a control circuit means for determining a drive differential signal between the opposing drive pair of the drive electrodes, determining a sense differential signal between the opposing sense pair of the sense electrodes, and applying feedback control signals to the set of drive electrodes based on the drive differential signal and the sense differential signal.