Micro-gyrometer with frequency detection

• US 7,389,690 B2
• Filed: 08/12/2005
• Issued: 06/24/2008
• Est. Priority Date: 08/13/2004
• Status: Active Grant

• Current Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Original Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Inventors: Robert, Philippe
• Primary Examiner(s): Kwok; Helen C.
• Application Number:
  US11/202,148
• Publication Number:
  US 20060032306A1
• Time in Patent Office: 1,047 Days
• Field of Search: 735/040.4, 735/041.2, 735/041.4, 735/041.6, 735/040.2
• US Class Current: 73/504.12
• CPC Class Codes: G01C 19/574 the devices having two sensing masses in anti-phase motion

Abstract

This invention suggests a micro-gyrometer, advantageously machined using conventional micro-electronic techniques, based on the detection of Coriolis forces generated by an angular movement Ω perpendicular to the direction of vibration of the masses free to move along the plane of the gyrometer. Coriolis forces are detected through the movement that they apply to the natural mode of a resonator coupled to the moving device.

Claims

1. Gyrometer comprising:

an excitation resonator, free to move in a plane, comprising two masses;

means for connecting the two masses to each other;

excitation means for putting the masses into movement in a first direction of the plane;

at least one detection resonator connected to the means for connecting the two masses of the excitation resonator;

means for exciting the at least one detection resonator; and

means for measuring the frequency of a natural mode of the detection resonator.

2. Gyrometer according to claim 1, further comprising a substrate to which each resonator is connected through at least one anchor point.

3. Gyrometer according to claim 2, wherein the substrate is a microtechnological support, the gyrometer being monolithic.

4. Gyrometer according to claim 1, wherein means for putting the masses into movement is fixed capacitive combs.

5. Gyrometer according to claim 1, wherein the connecting means comprise first and second connecting arms parallel to the first movement direction of the masses, and connected to the masses through bending arms, such that the connecting arms are perpendicular to the Coriolis force generated by the movement of the masses in the first direction and a rotation of the first excitation resonator from an axis perpendicular to the plane.

6. Gyrometer according to claim 5, wherein each connection arm is connected to a torsion axis.

7. Gyrometer according to claim 6, wherein the at least one detection resonator comprising a detection resonator connected to a first connecting arm at a first distance from the torsion axis.

8. Gyrometer according to claim 7, wherein the at least one detection resonator further comprising another detection resonator connected to the second connecting arm at a second distance from the torsion axis.

9. Gyrometer according to claim 8, wherein the first and the second distances are equal, and wherein the detection resonators are connected to the first and second arms between the corresponding torsion axis and the same mass.

10. Gyrometer according to claim 9 wherein the detection resonators are chosen from among the vibrating arms or tuning fork-shaped resonators.

11. Gyrometer according to claim 7, wherein the detection resonator connected to a first connecting arm comprising two detection resonators connected to the first connecting arm symmetrically about the torsion axis.

12. Gyrometer according to claim 11, further comprising two detection resonators connected to the second connecting arm, symmetric about the torsion axis and at the first distance from the torsion axis.

13. Gyrometer according to claim 12, wherein the detection resonators are chosen from among the vibrating beams or tuning fork-shaped resonators.

14. Gyrometer according to claim 5, wherein the detection resonator is hinged about a rigid arm.

15. Gyrometer according to claim 1, wherein the at least one detection resonator is connected to means for amplifying a force exerted on them by the first excitation resonator.

16. Gyrometer according to claim 15, wherein the means for amplifying comprise rigid arms hinged about a resonant element.

17. Gyrometer according to claim 15, wherein the at least one detection resonator is chosen from among the vibrating beams or tuning fork-shaped resonators.

18. Gyrometer according to claim 1, comprising means for activating the at least one detection resonator.

19. Gyrometer according to claim 18, wherein the means for activating the second resonators is a capacitive type means.

20. Gyrometer according to claim 19, wherein the gyrometer is monolithic.

21. Gyrometer according to claim 1, wherein the natural mode of the detection resonator is higher than a resonant frequency of the excitation resonator.

22. Gyrometer comprising:

An excitation resonator, free to move in a plane, comprising two masses;

first and second connecting arms parallel to a first movement direction of the masses, and connected to the two masses;

excitation means for putting the masses into movement in the first direction of the plane;

at least one detection resonator connected to first and second connecting arms;

means of exciting the detection resonator, and

means for measuring the frequency of a natural mode of the detection resonator.

23. Gyrometer comprising:

an excitation resonator, free to move in a plane, comprising two masses;

at least one connecting arm configured to connect the two masses to each other;

an excitation comb configured to put the masses into movement in a first direction of the plane;

at least one detection resonator connected to the at least one connecting arm configured to connect the two masses of the excitation resonator;

an excitation electrode configured to excite the at least one detection resonator; and

a detection electrode configure to measure the frequency of a natural mode of the detection resonator.