Hitachi, Ltd.

Hitachi Automotive Systems, Ltd.

Yasushi Okada

Masahiro Matsumoto

Toshiaki Nakamura

Satoshi Asano

Hisao Sonobe

Failures can be detected with high accuracy even the ambient temperature changes or background vibration is applied. An angular velocity sensor is composed of a vibrator which is elastically and displaceably supported on a substrate; a driving means which vibrates the vibrator in the drive axis direction horizontal to the substrate surface; a displacement detecting means in the detection axis direction, which detects a displacement of the vibrator in the detection axis direction horizontal to the substrate surface and perpendicular to the drive axis direction; an angular velocity detecting means which detects an angular velocity based on the displacement of the vibrator in the detection axis direction; a self-vibration detecting means that detects self-vibration of the vibrator, which is generated due to leakage in the detection axis direction of the vibration of the vibrator in the drive axis direction; a self-vibration feedback circuit which completely cancels the self-vibration of the vibrator; and an abnormality determining means which determines abnormality using an output from the self-vibration detecting means.

Angular velocity sensor

Disclosed herein is an angular velocity measuring device including: first and second oscillators elastically supported on a substrate; an elastic connecting beam elastically connecting the first and the second oscillator; and an oscillating means for oscillating the first and the second oscillator for differential oscillation, wherein a viscous force generating means for suppressing in-phase oscillation of the first and the second oscillator is incorporated into the elastic connecting beam.

Angular velocity measuring device

An oscillator is oscillated at a predetermined oscillation frequency. A detecting unit exerts Coriolis force on the oscillator. A repetitive control system applies an external force to the oscillator so as to cancel out the Coriolis force to achieve an angular velocity measuring operation at a high sensitivity and a high S/N ratio.

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Tendo, Japan

Yasushi Okada