Design and modeling of a MEMS accelerometer based on coupled mode-localized nonlinear resonators under electrostatic actuation

Abstract

A novel dual proof mass accelerometer is proposed by introducing mode localization in two electrostatically coupled resonators. The levering mechanism is utilized to amplify the inertial force applied axially to the two weakly coupled resonators. The dynamic model considering the electrostatic and mechanical nonlinearities is established and solved by the method of multiple scales, and also is validated by the harmonic balance method (HBM) coupled with the asymptotic numerical method (ANM). The linear and nonlinear sensitivities depicted as the difference of relative shift of amplitude ratio are investigated as well as the main influencing factors. It has been found that linear sensitivity is up to 4 orders of magnitude higher than that expressed by the difference of relative frequency shift. Also, the nonlinear sensitivity is further increased by 1.47 times comparing to the linear sensitivity. Moreover, the resolution is also greatly improved when the sensor is driven beyond its critical amplitude. Finally, the effect of the electrostatic coupling on the sensing performances is explored, and the optimal coupling voltage is theoretically identified at the limit of mode aliasing.