Micromachined gyroscopes with 2-DOF sense modes allowing interchangeable robust and precision operation

Patent metadata

Field	Value
Publication number	US-9310199-B2
Application number	US-201313866719-A
Country	US
Kind code	B2
Filing date	Apr 19, 2013
Priority date	Oct 23, 2009
Publication date	Apr 12, 2016
Grant date	Apr 12, 2016

Abstract

A z-axis gyroscope design is presented with a 2-degree of freedom (DOF) sense mode allowing interchangeable operation in either precision (mode-matched) or robust (wide-bandwidth) modes. This is accomplished using a complete 2-DOF coupled system which allows for the specification of the sense mode resonant frequencies and coupling independent of frequency. By decoupling the frame connecting the sense system to a central anchor, x-y symmetry is preserved while enabling a fully coupled 2-DOF sense mode providing control over both the bandwidth and the amount of coupling independent of operational frequency. The robust mode corresponds to operation between the 2-DOF sense mode resonant frequencies providing a response gain and bandwidth controlled by frequency spacing. Precision mode of operation, however, relies on mode-matching the drive to the second, anti-phase sense mode resonant frequency which can be designed to provide a gain advantage over a similar 1-DOF system.

First claim

We claim:

1. A micromachined z-axis vibratory rate gyroscope formed on a substrate comprising:
an outer anchor;
an inner anchor;
an outer decoupling drive frame coupled to the outer anchor restrained to oscillate substantially only in a drive direction;
an inner decoupling drive frame coupled to the inner anchor restrained to oscillate substantially only in a drive direction, the inner and outer decoupling drive frames being decoupled from each other and both resiliently coupled to the substrate;
a first sense mass m a resiliently coupled to the outer decoupling drive frame and restrained to oscillate substantially only in the sense direction;
a second sense mass m b resiliently coupled to the inner decoupling drive frame and restrained to oscillate substantially only in the sense direction, the first and second sense masses m a and m b being independently resiliently coupled to each other to allow relative oscillation in the sense direction;
a drive electrostatic comb coupled to either the inner decoupling drive frame or the outer decoupling frame or both; and
a sense electrostatic comb coupled to either the first sense mass or the second sense mass or both.

Assignees

• Univ California

Inventors

• Schofield Adam
• Trusov Alexander
• Shkel Andrei

Classifications

• G01C19/5733 Primary

  Structural details or topology · CPC title

• G01C19/56 Primary

  Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces · CPC title