Design and Sensitivity Analysis of a Micro-Resonant Accelerometer With Adjustable Stiffness

This article reports for the first time a stiffness-adjustable resonant accelerometer using the distributed electrostatic drive scheme, which has great potential in realizing high-frequency mode drive and improving the sensitivity of resonant accelerometers. First, a resonant accelerometer consisting of a sensitive mass block, a resonant beam, a driving electrode, two regulating electrodes, and a sensing electrode is designed, fabricated, and characterized. Then, the performance of the resonant beam in the resonant accelerometer has been fully assessed through its open-loop responses, with sensitivities of 85, 134, and 135 Hz/g based on the first three bending vibration modes. Through theoretical prediction and experimental measurement, it is found that with the increase of control voltage applied to the regulating electrodes, the sensitivity and signal-to-noise ratio (SNR) of resonant acceleration can be effectively improved. Typically, when the resonant beam works near the critical buckling, the sensitivity based on the first mode can be increased from 85 to 4920 Hz/g. Finally, the electrostatic force caused by the control voltage is experimentally proved to overcome the frequency-amplitude dependence caused by the stiffness hardening. The results of this article provide theoretical guidance and experimental support for the design of linear resonant accelerometers with high sensitivity.