US 6,164,134 A · Balanced vibratory gyroscope and amplitude control for same

Abstract

A balanced vibratory micro-gyroscope having an electrode pattern having four inner drive electrodes and four outer sense electrodes for providing balanced push-pull control of a cloverleaf micro-gyroscope. A control circuit utilizes equal and opposite input signals to the drive electrodes and processes output signals from the sense electrodes to precisely control the drive electrodes. Capacitance is added between opposing drive and sense electrodes pattern in order to null capacitive coupling effects between adjacent drive and sense electrodes. The control circuit linearizes the force on the micro-gyroscope thereby improving performance. Advantage is taken of Coulomb's Law to eliminate an electronic multiplier in the vibration amplitude control loop. A simplified full-wave rectifier further enhances the control circuit and operation of the micro-gyroscope. A closed negative feedback loop in the control circuit provides a corrective signal to the rate driving electrodes through rate sensing signals in order to prevent unwanted harmonic movement in the micro-gyroscope.

Claims17

Dependent claims

A micro-gyroscope comprising:

a. a base plate having a central hub having a passage therethrough;
b. an electrode pattern in said base plate, said electrode pattern comprising:
i. a plurality of inner electrodes spaced about said central hub and defining an outer periphery;
ii. a plurality of outer electrodes spaced about and surrounding said outer periphery of said inner electrodes, said outer electrodes being in the same plane as said inner electrodes;
iii. a continuous shield electrode in between each of said inner and outer electrodes, said shield electrode being grounded;
c. a resonator spaced from and located above said base plate, said resonator comprising:
i. a frame having a central hub having a passage therethrough;
ii. four leaves in said frame, said leaves arranged symmetrically around said central hub;
iii. a baton orthogonal to said frame, said baton attached to said central hub and said four leaves, said baton extending through said passage in said frame and through said passage in said base plate;
and
d. a control circuit for balancing said micro-gyroscope and for controlling vibrations of said micro-gyroscope.

8 more elements

A control circuit for a micro-gyroscope having a plurality of drive electrodes, a plurality of sense electrodes, and a vibrating element centered between said electrodes, said control circuit comprising:

means for producing a vibration drive voltage applied to one of said plurality of electrodes and an equal and opposite vibration drive voltage applied to another of said plurality of electrodes causing movement of said micro-gyroscope and sensed by at least two of said sense electrodes whereby said sense electrodes produce a signal;
a closed feedback loop that processes said signal to control said vibration drive voltage;
a negative feedback loop for providing a corrective signal to at least two of said driving electrodes wherein at least two of said sensing electrodes sense undesirable movements of said micro-gyroscope and produce a signal, said signal being processed by said negative feedback loop to provide equal and opposite signals to said at least two driving electrodes for offsetting said undesirable movements;
and
means for producing a capacitance between opposing drive and sense electrodes in order to avoid capacitive coupling between adjacent drive and sense electrodes.

2 more elements

Dependencies are inferred from the claim text.

Balanced vibratory gyroscope and amplitude control for same

Life of this patent

Balanced vibratory gyroscope and amplitude control for same

Life of this patent

Abstract

Claims17