Increasing the dynamic range of a MEMS gyroscope

• US 6,837,108 B2
• Filed: 04/23/2002
• Issued: 01/04/2005
• Est. Priority Date: 04/23/2002
• Status: Expired due to Fees

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Platt, William P.
• Primary Examiner(s): Williams, Hezron
• Assistant Examiner(s): Hanley, John C
• Application Number:
  US10/128,071
• Publication Number:
  US 20030196491A1
• Time in Patent Office: 987 Days
• Field of Search: 735/040.2, 735/041.2, 735/041.6, 73/13.7, 73/13.8, 73/17.7, 735/043.2, 324/115
• US Class Current: 73/504.16
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis

Abstract

A MEMS gyroscope system and method for increasing a dynamic range of the MEMS gyroscope is provided. By adjusting a scale factor of the MEMS gyroscope, the highest sensed rate will be increased, which increases the dynamic range. The scale factor may be adjusted by using a variable sense bias and/or an automatic gain control loop in sense electronics.

Claims

1. A method for increasing a dynamic range of a MEMS gyroscope, comprising in combination:

connecting a variable sense bias to at least one sense plate of the MEMS gyroscope, wherein the variable sense bias is operable to apply a sense bias voltage to the at least one sense plate; and

adjusting the sense bias voltage to change a scale factor of the MEMS gyroscope based on an angular rate input detected by the MEMS gyroscope.

2. The method of claim 1, wherein the variable sense bias is a set of switches connected to a variable power supply.

3. A method for increasing a dynamic range of a MEMS gyroscope, comprising in combination:

detecting an output of a gain located in sense electronics, wherein the sense electronics are connected to a MEMS gyroscope;

comparing the output of the gain with a reference voltage;

adjusting the output of the gain, wherein adjusting the output of the gain adjusts a scale factor of the MEMS gyroscope, wherein the scale factor is adjusted based on an angular rate input detected by the MEMS gyroscope.

4. The method of claim 3, further comprising providing a scale factor output.

5. The method of claim 3, wherein the output of the gain is connected to FET switches and a microprocessor.

6. The method of claim 5, wherein the microprocessor is operable to detect a voltage level at the output of the gain.

7. The method of claim 6, wherein the microprocessor is operable to compare the voltage level at the output of the gain with the reference voltage.

8. The method of claim 5, wherein the FET switches are connected to an input of the gain through resistors.

9. The method of claim 8, wherein the microprocessor is operable to open and close the FET switches.

10. The method of claim 9, wherein the output of the gain is determined by which of the FET switches are open and which of the FET switches are closed.

11. A system for increasing a dynamic range of a MEMS gyroscope, comprising in combination:

a MEMS gyroscope including at least one sense plate;

sense electronics connected to the at least one sense plate, wherein the sense electronics provide an angular rate output; and

a variable sense bias operable to apply a sense bias voltage to the at least one sense plate, wherein the sense bias voltage is adjusted to change a scale factor of the MEMS gyroscope based on an annular rate input detected by the MEMS gyroscope.

12. The system of claim 11, wherein the MEMS gyroscope is a tuning fork gyroscope.

13. The system of claim 11, wherein the MEMS gyroscope uses a Coriolis acceleration to detect an angular rate input.

14. The system of claim 11, wherein the sense electronics is operable to convert a current to a DC voltage.

15. The system of claim 14, wherein the DC voltage is proportional to the angular rate input detected by the MEMS gyroscope.

16. The system of claim 11, wherein the angular rate output is a DC voltage that is proportional to the angular rate input detected by the MEMS gyroscope.

17. The system of claim 11, wherein the variable sense bias is a set of switches connected to a variable power supply.

18. A system for increasing a dynamic range of a MEMS gyroscope, comprising in combination:

a tuning fork gyroscope including at least one sense plate;

sense electronics connected to the at least one sense plate, wherein the sense electronics is operable to convert a current to a DC voltage, and wherein the DC voltage is proportional to an angular rate input detected by the tuning fork gyroscope; and

a variable sense bias operable to apply a sense bias voltage to the at least one sense plate, wherein the sense bias voltage is adjusted to change a scale factor of the MEMS gyroscope based on the angular rate input detected by the tuning fork gyroscope.

19. A system for increasing a dynamic range of a MEMS gyroscope, comprising in combination:

a MEMS gyroscope including at least one sense plate;

sense electronics connected to the at least one sense plate, wherein the sense electronics includes a gain; and

an automatic gain control loop, wherein the automatic gain control loop is a feedback loop formed by connections between the gain, FET switches, and a microprocessor, wherein the automatic gain control loop adjusts an output of the gain, wherein adjusting the output of the gain adjusts a scale factor of the MEMS gyroscope, wherein the scale factor is adjusted based on an angular rate input detected by the MEMS gyroscope.

20. The system of claim 19, wherein the MEMS gyroscope is a tuning fork gyroscope.

21. The system of claim 19, wherein the MEMS gyroscope uses a Coriolis acceleration to detect an angular rate input.

22. The system of claim 19, wherein the output of the gain is connected to the FET switches and the microprocessor.

23. The system of claim 22, wherein the microprocessor is operable to detect a voltage level at the output of the gain.

24. The system of claim 23, wherein the microprocessor is operable to compare the voltage level at the output of the gain with a reference voltage.

25. The system claim 24, wherein the reference voltage is a sense bias voltage applied to the at least one sense plate.

26. The system of claim 25, wherein the sense bias voltage is produced by a variable sense bias.

27. The system of claim 26, wherein the variable sense bias is a set of switches connected to a variable power supply.

28. The system of claim 19, wherein the microprocessor is operable to open and close the FET switches, thereby controlling the scale factor of the MEMS gyroscope.

29. The system of claim 19, wherein the FET switches are connected to an input of the gain through resistors.

30. The system of claim 19, wherein the output of the gain is determined by which of the FET switches are open and which of the FET switches are closed.

31. The system of claim 19, wherein the microprocessor provides a scale factor output.

32. A system for increasing a dynamic range of a MEMS gyroscope, comprising in combination:

a tuning fork gyroscope including at least one sense plate;

sense electronics connected to the at least one sense plate, wherein the sense electronics includes a gain; and

an automatic gain control loop, wherein the automatic gain control loop is a feedback loop formed by the connections between the gain, FET switches, and a microprocessor, wherein the microprocessor is operable to detect a voltage level at the output of the gain and compare the voltage level with a reference voltage, wherein the microprocessor is operable to open and close the FET switches based on the comparison, wherein opening and closing the FET switches adjusts a scale factor of the MEMS gyroscope, wherein the scale factor is adjusted based on an angular rate input detected by the MEMS gyroscope.

33. The system of claim 32, wherein the microprocessor provides a scale factor output.