一种基于谐振音叉的新型差动式硅微加速度计设计与分析

Design and Analysis of a Novel Differential Si-Based Micro-Accelerometer Based on Resonant Fork

为提高谐振式加速度计灵敏度、稳定性以及减小加速度计体积,本文提出一种结构新颖的谐振式硅微加速度计。采用一级微杠杆机构对质量块惯性力进行放大,通过一对差动布置的双端固支音叉谐振器的固有频率变化检测惯性力,从而实现对加速度的测量。该加速度计可采用体硅加工工艺,给出了总体工艺流程。采用解析和有限元分析方法对加速度计敏感元件进行了分析,有限元分析结果与解析分析结果相吻合,有限元分析可得加速度计灵敏度为57.4 Hz/gn。分析结果表明该加速度计结构具有高灵敏度、高温度稳定性和小体积等优点。

In order to enhance the sensitivity, stability and to reduce the size of the resonant accelerometers, this paper proposes a novel structure for the resonant Si-based micro-accelerometer. Inertial force of the proof mass is amplified and measured by a one-stage micro-leverage mechanism and a pair of differential double-ended-tuning- fork （DETF）resonators respectively. From the natural frequency shift of the DETF, the acceleration can be deduced. Bulk-micromachining can be adopted to manufacture this accelerometer, and the corresponding general manufacturing process is presented. Analytical and finite element analysis （FEA）methods are applied to optimize the sensitive component of the accelerometer; the analytical result is in good agreement with that obtained by FEA method, the FEA sensitivity of the accelerometer is 57.4 Hz/gn. Results of the analyses show that this proposed ac- celerometer possesses high sensitivity, high temperature stability and small size.