高灵敏度、大带宽全石英谐振 MEMS 加速度计研究

A novel all-quartz resonant MEMS accelerometer structure has been designed. A mathematical modeling study is performed to analyze the sensitivity of the accelerometer and the resonant frequency of the resonant beam. Finite element analysis is used to obtain the sensitivity and natural frequency of the initial structural dimensions. The relative error between numerical simulation and mathematical analytical results is less than 4.5%, validating the effectiveness of both the mathematical analysis and numerical model. Based on the analytical mathematical model of sensitivity, through force analysis of the sensitive structure, it is found that the thickness of the proof mass and the thickness and width of the flexural support have a significant impact on the sensitivity of the accelerometer. Finite element simulation is employed to determine the optimal thickness of the proof mass. When the thickness of the proof mass is fixed and the dimensions of the flexural support vary, sensitivity and natural frequency change inversely. Using a simulation-mapping-fitting method, the dimensions of the flexural support structure with high sensitivity and high natural frequency were obtained. Experimental calibration showed that the sensitivity of the accelerometer is 77.21 Hz/g, with natural frequencies of 1 085 Hz for the IA (input axis), 910 Hz for the OA (output axis), and 840 Hz for the PA (pendulum axis). The measuring range reaches 80 g. The developed all-quartz resonant accelerometer simultaneously exhibits high sensitivity, large bandwidth, and high measuring range, enhancing the engineering applicability of quartz resonant accelerometers.