微机械陀螺的建模与仿真

Modeling and simulation of micromachined gyroscope

为了降低微机械陀螺系统的噪声和提高系统分辨率,依据电磁驱动电容检测式微机械陀螺的运动方程和接口电路的传递函数在Simulink仿真平台上建立了系统级仿真模型.模型中加入了传感器的机械热噪声、电路的电热噪声以及传感器内部的耦合效应等.模型不仅能够实现陀螺系统的功能性仿真,还能对各部分噪声源对系统性能的影响进行量化,获得不同耦合情况下的系统主要噪声源.系统噪声仿真结果表明,当陀螺器件内部耦合效应较小时,电容电压(CV)变换电路单元为主要噪声源;当陀螺器件内部耦合效应较大时,陀螺自激端输出信号的带通滤波放大电路单元为主要噪声源,并通过实验测试使仿真结果得到了验证.

A system level model was built according to the dynamic equation of micromachined gyroscope with electromagnetic driving and capacitive detecting and the transfer functions of the interface circuits on Simulink platform in order to reduce the noise of micromachined gyroscope system and enhance system resolution. Mechanical-thermal noise of sensor, electronic-thermal noise of circuits and coupling effects in sensor were added to the model. Therefore, the model not only could get the functional simulation results of gyroscope system, but also could quantify the effect of each noise source on system performance and find the main noise source under different coupling effects. Simulation results show that capacitance-voltage （CV） conversion circuit was the main noise source when the coupling effects in gyroscope were weak; the band-pass filter of gyroscope self-excitation circuit became the main noise source when the coupling effects were robust. Simulation results were validated with the experiment.