Whole angle mems gyroscope

Patent metadata

Field	Value
Publication number	US-2016341551-A1
Application number	US-201615160421-A
Country	US
Kind code	A1
Filing date	May 20, 2016
Priority date	May 22, 2015
Publication date	Nov 24, 2016
Grant date	—

Abstract

According to one aspect, embodiments herein provide a gyroscope comprising a central anchor, a plurality of internal flexures, a plurality of masses, each mass coupled to the central anchor via at least one of the plurality of internal flexures and configured to translate in a plane of the gyroscope, and a plurality of mass-to-mass couplers, each mass-to-mass coupler coupled between two adjacent masses of the plurality of masses, and a plurality of transducers, each configured to perform at least one of driving and sensing motion of a corresponding one of the plurality of masses, wherein the plurality of transducers is configured to drive the plurality of masses in at least a first vibratory mode and a second vibratory mode.

First claim

What is claimed is:

1 . A gyroscope comprising:
a central anchor; a plurality of internal flexures; a plurality of masses, each mass coupled to the central anchor via at least one of the plurality of internal flexures and configured to translate in a plane of the gyroscope; a plurality of mass-to-mass couplers, each mass-to-mass coupler coupled between two adjacent masses of the plurality of masses; and a plurality of transducers, each configured to perform at least one of driving and sensing motion of a corresponding one of the plurality of masses; wherein the plurality of transducers is configured to drive the plurality of masses in at least a first vibratory mode and a second vibratory mode.

2 . The gyroscope of claim 1 , wherein each transducer is located at a periphery of the corresponding one of the plurality of masses.

3 . The gyroscope of claim 1 , wherein at least one transducer is configured to electrostatically drive motion of its corresponding one of the plurality of masses.

4 . The gyroscope of claim 1 , wherein at least one transducer is configured to magnetically drive motion of its corresponding one of the plurality of masses.

5 . The gyroscope of claim 1 , wherein at least one transducer is configured to optically drive motion of its corresponding one of the plurality of masses.

6 . The gyroscope of claim 1 , wherein at least one transducer is configured to piezoelectrically drive motion of its corresponding one of the plurality of masses.

7 . The gyroscope of claim 1 , wherein at least one transducer is configured to thermally drive motion of its corresponding one of the plurality of masses.

8 . The gyroscope of claim 1 , wherein the plurality of transducers is further configured to drive the plurality of masses in an n=2 vibratory mode.

9 . The gyroscope of claim 8 , wherein the first vibratory mode and the second vibratory mode are 45° apart.

10 . The gyroscope of claim 8 , wherein the plurality of transducers is further configured to drive motion of the plurality of masses at a fixed amplitude in the first vibratory mode and to sense motion of the plurality of masses in the second vibratory mode.

11 . The gyroscope of claim 10 , further comprising a controller coupled to the plurality of transducers,
wherein the plurality of transducers is further configured to provide signals to the controller based on the sensed motion of the plurality of masses in the second vibratory mode, and wherein the controller is configured to calculate a rate of rotation of the gyroscope based on the signals.

12 . The gyroscope of claim 8 , wherein the plurality of transducers is further configured to drive motion of the plurality of masses such that a total vibrational energy is maintained across the first vibratory mode and the second vibratory mode and to sense a distribution of energy between the first vibratory mode and the second vibratory mode.

13 . The gyroscope of claim 12 , further comprising a controller coupled to the plurality of transducers,
wherein the plurality of transducers is further configured to provide signals to the controller based on the sensed distribution of motion between the first vibratory mode and the second vibratory mode, and wherein the controller is configured to calculate an angle of rotation of the gyroscope based on the signals.

14 . The gyroscope of claim 1 , wherein each mass-to-mass coupler includes a bar coupled to each adjacent mass via a flexural hinge, wherein the bar is configured to operate such that circumferential motion of one of the two adjacent masses of the plurality of masses to which it is coupled depends on radial motion of the other one of the two adjacent masses.

15 . The gyroscope of claim 1 , further comprising:
a plurality of outside anchors; a plurality of outside shuttles, each located at a periphery of a corresponding one of the plurality of masses; and a plurality of outside flexures; wherein each mass of the plurality of masses is suspended between the central anchor and the plurality of outside anchors via the plurality of internal flexures and the plurality of outside flexures; and wherein each one of the plurality of outside shuttles is configured to restrict rotation of its corresponding one of the plurality of masses.

16 . The gyroscope of claim 15 , wherein each one of the plurality of outside shuttles is further configured to decouple x- and y-motion of its corresponding one of the plurality of masses.

17 . The gyroscope of claim 15 , wherein each one of the plurality of outside shuttle is further configured to prevent force from being applied circumferentially to its corresponding one of the plurality of masses.

18 . The gyroscope of claim 1 , further comprising a plurality of internal shuttles, each one of the plurality of internal shuttles coupled between the central anchor and a corresponding one of the plurality of masses and configured to restrict rotation of its corresponding one of the plurality of masses.

19 . The gyroscope of claim 18 , wherein each one of the plurality of internal shuttles is further configured to decouple x- and y-motion of its corresponding one of the plurality of masses.

20 . The gyroscope of claim 1 , further comprising a plurality of angled electrodes, each angled electrode coupled to a corresponding one of the plurality of masses and configured to trim the cross spring term of the corresponding one of the plurality of masses.

21 . The gyroscope of claim 20 , wherein in trimming the cross spring term of its corresponding one of the plurality of masses, each angled electrode is configured to:
generate a radial force component in the second vibratory mode in response to a circumferential motion of its corresponding one of the plurality of masses in the first vibratory mode; and generate a circumferential force component in the second vibratory mode in response to a radial motion of its corresponding one of the plurality of masses in the first vibratory mode; wherein the radial force component and the circumferential force component are configured to either assist or oppose the vibration of the plurality of masses in the second vibratory mode to trim the cross spring term.

22 . The gyroscope of claim 1 , wherein the gyroscope is implemented on a cubic crystal based substrate having a (100) direction plane and a (110) direction plane; and
wherein at least one of the plurality of internal flexures is oriented equidistant from the (100) direction plane and the (110) direction plane.

23 . The gyroscope of claim 22 , wherein the at least one of the plurality of internal flexures is oriented 22.5° from the (100) direction plane and the (110) direction plane of the cubic crystal-based substrate.

24 . The gyroscope of claim 22 , wherein the cubic crystal-based substrate is a Silicon (Si) based substrate

25 . The gyroscope of claim 1 , wherein the plurality of masses includes a plurality of wedge-shaped masses.

26 . The gyroscope of claim 1 , wherein the plurality of masses is arranged symmetrically about the central anchor.

27 . The gyroscope of claim 1 , wherein the gyroscope has a thickness, and wherein the
plurality of internal flexures includes flexures having a width that is at least five times narrower than the thickness of the gyroscope.

28 . The gyroscope of claim 1 , wherein th

Assignees

• Charles Stark Draper Laboratory Inc

Inventors

• Cook Eugene H
• Weinberg Marc S
• Bernstein Jonathan J

Classifications

• G01C19/5733

  Structural details or topology · CPC title

• G01C19/5726 Primary

  Signal processing · CPC title

• G01C19/5684

  the devices involving a micromechanical structure · CPC title