馈通效应下微机械陀螺仪标度因数特性分析

Analysis of Scale Factor Characteristics of MEMS Gyroscopes Under Feedthrough Effect

微机械陀螺仪可动质量块、衬底和电极间存在复杂的寄生电容,使得陀螺仪的反馈力电极与检测读出电极间存在馈通效应。为研究馈通效应对微机械陀螺仪标度因数特性的影响,首先基于理论模型分析了不同模态频差下,馈通效应对检测回路开环零点分布的影响,进而分析了存在馈通时模态频差对标度因数的影响。其次,建立了存在馈通时的力反馈仿真模型。最后设计了基于分时控制的馈通抑制方案,实验结果显示,无馈通抑制和有缓冲周期分时控制的标度因数最大变化量分别为70.2%和1.3%。仿真与实验结果均表明馈通效应越显著,标度因数随模态频差的变化幅度越大。

There are complex parasitic capacitors among the movable mass,substrate and electrode of micromechanical gyro-scope,leading to the feedthrough effect between the feedback electrode and the detection readout electrode.To investigate the in-fluence of the feedback effect on the scale factor characteristics of MEMS gyroscopes,theoretical modeling was employed to ana-lyze the impact of the feedthrough effect on the open-loop zero distribution of the detection circuit under different mode frequency differences.Subsequently,the influence of the mode frequency difference on the scale factor in the presence of feedthrough was examined.A force feedback simulation model was established to reflect the impact of feedthrough.Finally,a feedthrough suppression scheme based on time-division control was designed,and the experimental result demonstrate that without feedthrough suppression and with buffered period time-division control,the maximum variation in the scale factor is 70.2%and 1.3%,respec-tively.Both simulation and experimental results indicate that the more significant the feedthrough effect is,the greater the ampli-tude of scale factor variation with mode frequency difference is.