Resilience to Vibration of a Tuning Fork MEMS Gyroscope

Abstract

This paper investigates the resilience to mechanical vibration of tuning fork MEMS gyroscopes and presents the limitations of this device. We focus our study on mechanical vibrations near the first three resonance frequencies corresponding to the in-phase and anti-phase drive modes and the sense mode. This original work quantifies the rejection capability of the anti-phase mode to external vibrations in comparison to the in-phase mode resulting in a ratio of 390. In-phase frequency mechanical vibrations can result in mechanical non-linearities visible in the gyroscope response. This paper demonstrates also the strong impact of the in-phase mode on the gyroscope operation leading to failure when it is excited simultaneously with the anti-phase mode. This issue is common to tuning fork gyroscopes and only phase mode control or shift to higher frequencies can preserve normal gyroscope operation at the bandwidth 0 – 50 kHz.