微隧道式加速度计的最优控制

Abstract

为了扩大隧道式加速度计(MTA)的动态测量范围并通过降低系统中的主要噪声来提高器件的性能,本文为隧道式加速度计(MTA)设计了线性二次高斯(lQg)控制器。推导了微隧道式加速度计的线性化状态-空间方程;依据分离定理,设计了卡尔曼滤波器和最优状态反馈控制器;最后,在MATlAb/SIMulInk中构建了由卡尔曼滤波器和最优状态控制器串联的lQg仿真系统并进行了动态和静态测试。仿真结果表明,lQg最优控制系统能够将微隧道式加速度计的带宽从2x103 rAd/S扩大到3x106 rAd/S。通过lQg最优控制,静态测试结果显示其静态隧道电流的波动从1nA~2.95nA降到0.73nA~1.14nA;动态实验数据表明其在方波加速度信号的作用下能够将隧道间隙维持在1nM。

To enlarge the dynamic measurement range of a Micromachined Tunneling Accelerator(MTA) and to improve its performance by reducing the influence of main noise operated in a closed-loop mode,a Linear Quadratic Gaussian(LQG) optimal controller was designed for our MTA to maintain a constant tunneling gap.The linear state space equation for the MTA was deduced,and an Kalman filter and an optimized sate feedback controller were designed.Finally,a simulation system was constructed by combining the Kalman filter and the optimized sate feedback controller in series,and simulation tests were performed.Obtained results show that the bandwidth of the MTA has been increased from 2×103 rad/s to 3×106 rad/s by the optimal control system.Moreover,the fluctuation of the static tunneling current is decreased from 1-2.95 nA to 0.73-1.14 nA from a static test and the distance from the proof mass to the tunneling electrode is effectively regulated to its nominal value of 1 nm under the dynamic square-wave accelerator.