Abstract: A motion sensor (10) includes a micromachined sensing structure and a number of capacitive electrodes (20) disposed about a periphery thereof. The sensing structure includes a ring (14) supported above a substrate (12) so as to have an axis of rotation normal to the substrate (12), and a number of springs (16) attached to a post (18) positioned at the center of the ring (14). Certain diametrically opposed ones of the capacitive electrodes (20) are configured as drive electrodes (20a), and other diametrically opposed ones of the capacitive electrodes (20), positioned 90 degrees relative to the corresponding drive electrodes (20a) are configured as sense electrodes (20b). Signals produced at the opposed sense electrodes (20b) are conditioned and coupled to a common input of an amplifier circuit (64,70).

Abstract: A motion sensor having a micromachine sensing element and electrodes formed on a silicon chip. The sensing element includes a ring supported above a substrate so as to have an axis of rotation normal to the substrate. Surrounding the ring is at least one pair of diametrically-opposed electrode structures. The sensing ring and electrode structures are configured to include interdigitized members whose relative placement to each other enables at least partial cancellation of the effect of differential thermal expansion of the ring and electrodes. As a result, the performance of the motion sensor is, to first order, insensitive to temperature variation. The sensor further includes circuitry for creating and detecting an electrostatic force between the interdigitized members of the sensing ring and electrode structures.

Abstract: A yaw sensor for automotive controls has a microstructure vibrating ring excited by a driving circuit. The driving circuit comprises an amplitude control loop which delivers voltage pulses at the resonant frequency of the ring. A compensation signal is derived from a comparison of a sensed vibration amplitude to a desired vibration amplitude. Failure of vibration is detected by comparing the compensation signal to a threshold which is higher than a normal compensation signal. Alternatively, vibration failure is detected by comparing the sensed vibration to a threshold lower than the desired vibration amplitude. Upon such failure, the yaw output signal is replaced by ground potential.

Abstract: A yaw sensor for automotive controls has a microstructure vibrating ring excited by a driving circuit. The driving circuit comprises an amplitude control loop which delivers voltage pulses at the resonant frequency of the ring. A compensation signal is derived from a comparison of a sensed vibration amplitude to a desired vibration amplitude. Failure of vibration is detected by comparing the compensation signal to a threshold which is higher than a normal compensation signal. Alternatively, vibration failure is detected by comparing the sensed vibration to a threshold lower than the desired vibration amplitude. Upon such failure, the yaw output signal is replaced by ground potential.