微机械陀螺仪反馈控制器鲁棒性分析及闭环接口检测电路设计

Robustness analysis of a type of feedback controller and design of closed-loop sensing circuit of micro-machined gyroscope

在分析微机械陀螺仪静电力反馈检测结构的基础上,提出了一种对现有Sigma-Delta静电力反馈检测方式的改进设计.对微机械陀螺仪闭环检测系统进行了离散化处理.基于Lyapunov稳定性原理,构造了一类能够使系统有限时间稳定的输出反馈控制器,并对其鲁棒性能进行了分析.该电路系统在Cadence平台下使用AMS 0.35μm CMOS工艺实现,完成了包括前端敏感电路、调制解调器和反馈控制器在内的关键部分的设计,并通过了仿真验证.系统的关键性能与比例-积分-微分(PID)控制器改进的静电力反馈电路进行了比较.分析结果表明,改进的闭环检测系统在陀螺信号带宽上信噪比达到106 dB,在扰动发生后可以在130 ms之内恢复到平衡状态,所需时间短于采用PID控制器的检测回路.因此,加入了输出反馈控制器的闭环系统比普通系统具有更加良好的检测性能.

Based on the analysis of micro-machined gyroscope force-balanced feedback sensing structure,a modification of the general Sigma-Delta force-balanced sensing scheme is proposed.Discretization of micro-machined gyroscope closed-loop sensing system is described.A type of output feedback controller,which can stabilize the system within finite time,is constructed based on Lyapunov stability theory,and the robustness of the controller is investigated.Overall system is realized with AMS 0.35μm CMOS（complementary metal oxide semiconductor） technology by Cadence tool.Main parts including front-end circuit,Sigma-Delta modulator and feedback controller are designed and simulated.Key characteristic of the system is compared with that of the force-balanced circuit improved by proportional-integral-derivative（PID） controller.The analysis results show that the modified closed-loop sensing system achieves a 106 dB SNR（signal to noise ratio） in gyroscope signal band,and restabilizing time after disturbance is within 130 ms,which is shorter than that of the sensing scheme with PID controller.Therefore,the closed-loop system optimized by output feedback controller demonstrates a better sensing performance than general type.