Multimode TED-tuned beam mass damper for low-g capacitive MEMS accelerometers VRE reduction

Abstract

Capacitive Micro-Electro-Mechanical Systems (MEMS) accelerometers for quasi-static applications are susceptible to vibration rectification error (VRE) when the ambient AC vibration signals get rectified to DC. Studies to mitigate the VRE have relied on the sigma-delta filtering algorithm with closed-loop feedback as well as the adoption of vibration-insensitive frequency modulation (FM) instead of conventional amplitude modulation. In this study, we propose a novel solution to VRE caused by asymmetric railing introducing multimode thermoelastic damping (TED) tuned beam mass damper (TBMD) integrated into the MEMS accelerometer effectively functioning as a compensator. Our contribution breaks through the microfabrication limitation of damping elements by utilizing intrinsic TED in MEMS material. The damper elements were alternately tuned up to the third flexural mode due to MEMS manufacturing constraints. This was done through parametric sweeps in numerical simulations on single-axis capacitive MEMS accelerometer integrated with multimode TED-damped TBMD. According to simulation results, the higher the mode shapes of the TED-damped tuned beam mass damper, the higher the damping effect and the better the vibration rectification factor.