A micromachined electrostatically suspended gyroscope with digital force feedback

This paper presents the design and system modeling of a micromachined electrostatically suspended gyroscope incorporated in a ZA force-feedback system. Unlike a typical micromachined gyro, the gyroscope reported here employs a levitated proof mass. The micromachined disk-shaped proof mass, which has no mechanical support, is suspended and spun electrostatically to function similar to a mechanical flywheel gyro. The precession of the disk caused by angular motion is sensed capacitively. The disk is rebalanced to its nominal position by a ZA control system. Such a system provides a direct digital output, which is a measure of the external rate of rotation. Analytical and finite element models are used to study the behavior of the sensor. The geometry of the sense and control electrodes is optimized to obtain maximum pick-off signal. System level simulations are performed to study the device performance of such a gyro