翘翘板摆式MEMS加速度计振动整流误差

摘要

MEMS accelerometers have the advantages of small volume,low cost,high reliability and easy-tobatch production,which make them have wide application in the field of tactical grade weapons.But the output error induced by vibration (vibration rectification error,VRE) is the main error degrading their performances for inertial navigation grade applications.In order to suppress the VRE,the structure nonlinearity of the actuator caused by asymmetry of the sensor chip and electronic offset error was theoretically analyzed,then the resulted system level error model was simulated according to the vibration calibration tests,and the relationship between nonlinearity coefficients and error sources was determined.At last,the comparison tests for the VRE and nonlinearity coefficients of the MEMS accelerometer before and after main error source (electronic offset) optimization were done.The results show that the second order nonlinearity of the MEMS accelerometer can be depressed from 1E-4g/g2 to 5E-6g/g2 after the optimization.%MEMS加速度计凭借其体积小、成本低、可靠性高及可批量生产等优势,已经在战术级精度的武器领域得到了广泛应用.但是,在振动环境下的输出误差(振动整流误差)成为其向导航级精度发展的主要指标瓶颈.为了减小MEMS加速度计的振动整流误差,对传感器芯片结构不对称性和电路零位误差引起的力矩器结构非线性进行了理论分析,然后按照振动法测非线性的方式对上述误差源引起的系统级误差模型进行了仿真试验验证,确定了各误差源与加速度计非线性系数间的影响关系.最后,对主要误差源(电路零位)优化前后的MEMS加速度计振动整流误差和非线性系数进行了测试对比,结果表明:优化后,在50—1500Hz频率范围内MEMS加速度计二阶非线性的最大值可由1E-4g/g2降至5E-6g/g2.