微加速度计固有频率的推导及验证

A Calculation Method and Verification for Natural Frequency of Micro Accelerometer

为了解决压阻式加速度计的动态特性欠佳的共性,避免微加速度计在工作过程中因为共振导致结构损坏,在结构设计过程中选择合理固有频率是至关重要的。本文就针对一种四边八梁结构的高gn值压阻式加速度计,通过力学知识,简化结构并推导出其固有频率的理论计算公式,并利用有限元仿真软件和测试高gn值加速度计频率特性的方法,对此理论公式进行了仿真和实验验证,证明此理论公式的正确性和可用性。这样,在加速度计结构的设计过程中,可以直接利用此公式计算出结构的固有频率,从而减化加速度计的结构设计和优化过程,设计出最合理的固有频率结构。

A calculation and test method for natural frequency of high-gn micro accelerometer with complex structures is put forward. A novel calculation method, which can significantly simplify the process of the structure design, is presented and confirmed by experiment. A simplified analytical model is established to describe the accelerometer＇s mechanical behaviour and deduce the formula for natural frequency. Finite element modeling was also conducted to verify the formula and evaluate the natural frequency of the microaccelerometer. Comparison of the results obtained from the analytical model and finite element simulation shows good agreement. Finally, a shock comparison method design, which can test the high frequency characteristic of accelerometer, is used to verify the formula of the natural frequency by testing the frequency characteristic of an actual accelerometer.