Drive mode control for MEMS gyroscopes with electrostatically tunable structure

Variable-area capacitor with tuning capability is used to control the drive mode of MEMS gyroscopes for constant-frequency oscillation. The proposed control approach tunes the drive axis natural frequency to a preselected frequency and regulates the amplitude of the drive axis vibration. The algorithm mainly implemented using a field-programmable-gate-array (FPGA) is tested on a MEMS gyroscope operating at atmospheric pressure which is of our own manufacture. First measurement results of the novel digital prototype show the amplitude variance of the detected signal of drive axis is 26ppm in an hour while the phase variance is 45ppm.