Techniques for reducing variations in a difference between drive mode and sense mode frequency in a split mode mems gyroscope
AssigneeHoneywell International Inc.
InventorsAndrew Roberts Brown, Markus Hans Gnerlich, Ved Gund, John Reinke
Life of this patent
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Abstract
Techniques are provided for reducing variation of a difference between a frequency of a sense mode and a frequency of a drive mode in a split mode microelectromechanical system (MEMS) gyroscope. Circuitry monitors each such frequencies. In response to such frequencies, the circuitry injects a control signal, into one or more quadrature force rebalance combs of a proof mass system of the MEMS gyroscope, to facilitate such variation reduction.
Claims20
A method for diminishing variations in a difference in frequency between a sense frequency of a sense mode and a drive frequency of a drive mode in a microelectromechanical system (MEMS) gyroscope including a proof mass system which includes one or more proof masses, one or more sense combs or electrodes, one or more drive pickoff combs or electrodes, one or more drive combs or electrodes, and one or more quadrature force rebalance (QFR) combs or electrodes, wherein the proof mass system is configured to sense rotation around an axis of rotation, the method comprising:
- receiving, from the one or more sense combs or electrodes, a sense motion electrical signal;
- receiving, from the one or more drive pickoff combs or electrodes, a drive motion pickoff electrical signal;
- amplifying each of the sense motion electrical signal and the drive motion pickoff electrical signal;
- using an amplified sense motion electrical signal and an amplified drive motion pickoff electrical signal, generating a rate signal representing a rate of rotation around the axis of rotation;
- using the amplified drive motion pickoff electrical signal, generating a drive electrical signal configured to excite drive mode motion;
- receiving, at the one or more drive combs or electrodes, the drive electrical signal;
- using a quadrature sense motion signal, generating at least one QFR control signal, wherein the quadrature sense motion signal is a signal representing motion of the one or more proof masses in a sense mode and which is ninety degrees out of phase from the rate signal;
- using the amplified sense motion electrical signal, generating an alternating current (AC) signal with a frequency that is the difference in frequency;
- using the frequency of the amplified sense motion electrical signal and a frequency of the amplified drive motion pickoff electrical signal, generating a delta f control signal which is configured to diminish the variations in the difference;
- and
- receiving, at the one or more QFR combs or electrodes, the at least one QFR control signal, the AC signal, and the delta f control signal.
A microelectromechanical system (MEMS) gyroscope which diminishes variations in a difference in frequency between a sense frequency of a sense mode and a drive frequency of a drive mode, the MEMS gyroscope comprising:
- a proof mass system including one or more proof masses, one or more sense combs or electrodes, one or more drive pickoff combs or electrodes, one or more drive combs or electrodes, and one or more quadrature force rebalance (QFR) combs or electrodes, wherein the proof mass system is configured to sense rotation around an axis of rotation and generate a sense motion electrical signal from the one or more sense combs or electrodes and a drive motion pickoff electrical signal from the one or more drive pickoff combs or electrodes;
- and
- circuitry configured to:
- receive, from the one or more sense combs or electrodes, the sense motion electrical signal;
- receive, from the one or more drive pickoff combs or electrodes, the drive motion pickoff electrical signal;
- amplify each of the sense motion electrical signal and the drive motion pickoff electrical signal;
- using an amplified sense motion electrical signal and an amplified drive motion pickoff electrical signal, generate a rate signal representing a rate of rotation around the axis of rotation;
- using the amplified drive motion pickoff electrical signal, generate a drive electrical signal configured to excite drive mode motion;
- receive, at the one or more drive combs or electrodes, the drive electrical signal;
- using a quadrature sense motion signal, generate at least one QFR control signal, wherein the quadrature sense motion signal is a signal representing motion of the one or more proof masses in a sense mode and which is ninety degrees out of phase from the rate signal;
- using the amplified sense motion electrical signal, generate an alternating current (AC) signal with a frequency that is the difference in frequency;
- using the frequency of the amplified sense motion electrical signal and a frequency of the amplified drive motion pickoff electrical signal, generate a delta f control signal which is configured to diminish the variations in the difference;
- and
- receive, at the one or more QFR combs or electrodes, the at least one QFR control signal, the AC signal, and the delta f control signal.
An apparatus, comprising:
- amplifiers configured to receive and amplify each of a sense motion electrical signal and a drive motion pickoff electrical signal;
- and
- circuitry configured to:
- receive, from one or more sense combs or electrodes of a proof mass system, the sense motion electrical signal;
- receive, from one or more drive motion pickoff combs or electrodes of the proof mass system, the drive motion pickoff electrical signal;
- using an amplified sense motion electrical signal and an amplified drive motion pickoff electrical signal, generate a rate signal representing a rate of rotation around an axis of rotation;
- using the amplified drive motion pickoff electrical signal, generate a drive electrical signal configured to excite drive mode motion;
- transmit, to one or more drive combs or electrodes, the drive electrical signal;
- using a quadrature sense motion signal, generate at least one quadrature force rebalance (QFR) control signal, wherein the quadrature sense motion signal is a signal representing motion of the one or more proof masses in a sense mode and which is ninety degrees out of phase from the rate signal;
- using the amplified sense motion electrical signal, generate an alternating current (AC) signal with a frequency that is a difference between a sense frequency of a sense mode of the proof mass system and a drive frequency of a drive mode of the proof mass system;
- using the frequency of the amplified sense motion electrical signal and a frequency of the amplified drive motion pickoff electrical signal, generate a delta f control signal which is configured to diminish variations in the difference;
- and
- transmit, to one or more QFR combs or electrodes of the proof mass system, the at least one QFR control signal, the AC signal, and the delta f control signal.
Dependencies are inferred from the claim text.