Frequency response of in-plane coupled resonators for investigating the acceleration sensitivity of MEMS tuning fork gyroscopes

Abstract

The frequency response of in-plane coupled resonators is used for investigating the acceleration sensitivity of a MEMS tuning fork gyroscope (TFG) and a new method of suppressing the acceleration output is presented. The unbalancing of two sense resonators in the TFG caused by fabrication errors converted an external vibration into anti-phase mode excitation. To reduce the acceleration output, decoupling between in- and anti-phase modal frequencies [decoupling ratio (DR)] is crucial, since coupled resonators may cause large anti-phase vibrations from the acceleration. The acceleration output model was verified using two coupled resonators with 1 and 5 % stiffness unbalance. FEM simulation results showed a 25 % reduction in the anti-phase vibration by increasing the decoupling ratio from 0.09 to 0.29, irrespective of the coupled resonators designs. Quantitative analysis of a TFG based on coupled resonators with 1 % stiffness unbalance showed the acceleration output decreased from 5.65 to 1.43 deg/s/g.