Design and fabrication of an automatic mode controlled vibratory gyroscope

In this paper, we present a new approach for performance enhancement of MEMS vibratory gyroscope by means of automatic mode control scheme. The suggested method automatically tunes resonant frequencies of two lateral modes to be identically matched. This draws sensitivity improvement of the sensor and removes manual tuning effort, which are desirable features to achieve a high performance for the mass productive sensor like vibratory gyroscopes. In this paper, we designed and fabricated an electrostatically tunable gyro structure of parallel-type sensing electrodes and automatic mode tuning circuit that utilizes a PLL-based two self-oscillation loops for both driving and sensing mode.