馈通对硅微机械陀螺零偏影响及其抑制研究

Research on Effect of Feedback on Zero Bias of Silicon Micromechanical Gyroscopes and Suppression

硅微机械陀螺仪激励电极及读出电极间存在寄生电容,进而在读出信号中引入与其同频同相的馈通干扰信号。针对此现象,采用时域法对馈通干扰下力平衡模式的零偏特性进行理论推导,通过Simulink仿真及实验对结论进行验证。研究表明:馈通干扰导致力平衡模式驱动力一定时,陀螺零偏随模态频差改变发生变化。随后根据硅微机械陀螺仪静电力生成原理,设计一种采用半频谐振信号检测环路力平衡的控制系统,并通过实验验证了陀螺零偏在90 Hz模态频差变化范围内波动不超过0.17%,馈通对零偏的影响得到有效抑制。

The parasitic capacitance between the excitation electrode and the readout electrode of a silicon micromechanical gyroscope introduces a feedthrough disturbance signal.The feedthrough signal is in the same frequency and phase as the useful signal.In response to this phenomenon,the time-domain method was used to derive the zero bias characteristics of the force rebalance mode under feedthrough disturbance,and the conclusion was verified through Simulink simulation and experiments.Research shows that when the driving force is constant in the force rebalance mode,feedthrough disturbance causes the zero bias to change with the change of motion frequency difference.Subsequently,based on the principle of electrostatic force generation in silicon micromechanical gyroscopes,a control system using half frequency resonant signals to test circuit force balance is designed.The final experiment shows that the gyro zero bias does not change by more than 0.17%within the range of 90 Hz modal frequency difference variation,thus the influence of feedthrough on zero bias is effectively suppressed.