Robust micro-rate sensor actuated by parametric resonance

Loss in sensitivity, commonly presented in micro-gyroscopes based on harmonic oscillators [N. Yazdi, F. Ayazi, K. Najafi, Micromachined inertial sensors, Proceedings of the IEEE 86 (8)], can be overcome by using parametric resonance as an actuation mechanism. We demonstrate experimentally that using a parametric resonance based actuator, the drive-mode signal has a rich dynamic behavior with a large response in a large bandwidth (1 kHz). In this way the system is able to induce oscillations in the sense-mode by Coriolis force coupling, despite a clear disparity on their fundamental frequencies. Thus we propose a micro-gyroscope that is less sensitive to parameter variations due to its inherent dynamical properties. The device is fabricated using a single mask SOI process and in this paper we report its complete rate table characterization including off-axis isolation, drift, hysteresis and noise.