为了提高硅微机械陀螺(SMG)的性能,研究了一种基于四阶机电结合带通Σ-Δ调制器(SDM)的硅微机械陀螺力反馈闭环检测方法。基于谐振器级联谐振前馈(CRFF)结构设计了该方法的仿真模型,并利用商用软件SD TOOLS计算了环路参数。采用MATLAB/SIMULINK对设计结果进行了行为级仿真,结果表明,1 Hz条件下环路的信噪比达到了109.2 dB,符合设计预期。在此基础上,以现场可编程门阵列(FPGA)为数字处理核心搭建了硅微机械陀螺数字化测控电路并进行了性能测试。结果表明,采用带通SDM闭环检测技术和数字化闭环驱动技术后,硅微机械陀螺的Allan方差零偏不稳定性约为1.15(°)/h,角度随机游走约为7.74×10-2(°)/√h,且信噪比参数满足了设计目标。 得到的结果证明了设计方法的正确性;显示提出的带通SDM力反馈闭环检测方法有助于提高SMG的性能,拓展其应用领域。

To enhance the performance of a silicon micromachined gyroscope,a force feedback close-loop detection method based on a fourth-order electromechanical bandpass Sigma Delta modulator(SDM) was researched. A simulation model was established based on Cascade Resonant Feed Forward(CRFF) structure of a resonator. Meanwhile,the loop parameters were calculated with the commercial software SD TOOLS. Then behavioral simulations were carried out with MATLAB/SIMULINK to test the results. The results suggest that the Signal to Noise Ratio(SNR) of the loop achieves 109.2 dB at the bandpass of 1 Hz,which meets the previous expectation. A force feedback close-loop detection system for the silicon micromachined gyroscope was designed by using a Field Programming Gate Array(FPGA) as the processing core,and the properties of gyroscope were tested. Experiments indicate that based on this detecting method and digital close-loop driving technology,the zero bias instability of the gyroscope achieves 1.15(°)/h,and the Angle Random Walk (ARW) is around 7.74×10-2(°)/√h. Meanwhile,the Signal and Noise Ratio(SNR) meets the designed specifications. These results verify the validity of the detecting technique. The method is conductive to improving the performance of the SMGs and extending their application fields.