Continuous monitoring of drive amplitude in vibrating microelectromechanical gyroscopes
AssigneeMurata Manufacturing Co., Ltd.
InventorKimmo Törmälehto
Life of this patent
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Abstract
The disclosure relates to a microelectromechanical gyroscope comprising at least one mass element, a drive actuator and sense electrodes. The at least one mass element is configured to be driven by the drive actuator into oscillating movement with a drive oscillation frequency ωD, and the sense electrodes are configured to produce a sense signal from the oscillating movement of the at least one mass element. The gyroscope control circuit comprises an amplitude detection unit which detects a sense signal amplitude at the frequency 2ωD. This amplitude yields a measure of drive oscillation amplitude. Amplitude detection at the frequency ωD yields a measure of angular rotation rate.
Claims17
A microelectromechanical gyroscope comprising at least one mass element, a drive actuator, sense electrodes, and a gyroscope control circuit, wherein—the drive actuator is configured to be controlled by a drive signal comprising a drive signal amplitude and a drive signal frequency,
- the at least one mass element is configured to be driven by the drive actuator into a drive oscillation movement with a drive oscillation frequency ωD, and
- the sense electrodes are configured to produce a sense signal from a sense oscillation movement of the at least one mass element, the sense signal including a first component induced by the effect of the Coriolis force on the at least one mass element,
- wherein the gyroscope control circuit comprises an amplitude detection unit which detects the effect of the Coriolis force from a sense signal amplitude at the frequency ωD,
- and the sense signal has a second component with a second harmonic frequency 2ωD,
- and the gyroscope control circuit comprises a second amplitude detection unit which detects the sense signal amplitude at the second harmonic frequency 2ωD.
A method for operating a microelectromechanical gyroscope comprising at least one mass element, a gyroscope control circuit, and a drive actuator controlled by a drive signal comprising a drive signal amplitude and a drive signal frequency, wherein
- the at least one mass element is driven by the drive actuator into a drive oscillation movement with a drive oscillation frequency ωD,
- a sense signal is produced from a sense oscillation movement of the at least one mass element, the sense signal including a first component induced by effect of the Coriolis force on the at least one mass element,
- wherein an amplitude detection unit in the gyroscope control circuit detects the effect of the Coriolis force from a sense signal amplitude at the frequency ωD,
- the sense signal has a second component with a second harmonic frequency 2ωD,
- the sense signal amplitude is detected at the second harmonic frequency 2ωD in the gyroscope control circuit,
- and a second amplitude detection unit in the gyroscope control circuit detects the sense signal amplitude at the second harmonic frequency 2ωD.
Dependencies are inferred from the claim text.