为提高扫描电化学显微镜(SECM)微定位系统的运动定位精度,对其压电工作台的数学模型和控制器设计进行了研究。介绍了压电工作台的动态迟滞模型方程和采用Prandtl-Ishlinskii(PI)迟滞算子的动态迟滞模型,并在此基础上设计了压电工作台的复合控制方案。以CHI900B型扫描电化学显微镜的三维压电工作台为实验对象,对动态迟滞模型的具体建模过程进行了阐述,并验证了控制器的性能。在100 V/s和900 V/s两种不同输入电压速率下进行运动定位实验,动态迟滞模型平均误差分别为0.08μm和0.11μm,精度明中显优于压电工作台的线性动态模型和PI迟滞模型。复合控制方案下,系统跟踪±400μm/s任意三角波的平均误差为0.085μm,最大误差为0.105μm 跟踪复频波的平均误差为0.105μm,最大误差为0.115μm。控制效果较好。
In order to improve the dynamic positioning precision of scanning electrochemistry microscope (SECM), the mathematic modeling and controller design of the piezo-stage are studied. The dynamic hysteresis model equation of the piezo-stage is introduced. Furthermore, the dynamic hysteresis model based on Prandtl-Ishlinskii (PI) hysteresis operator is given, and a composite control strategy is designed. Experiments on the piezo-stage of CHI900B SECM elaborate the building process of the dynamic hsyteresis model, and the performance of the controller is also proved. Experiments with different input voltage rates (100 V/s and 900 V/s) indicate that the mean errors of the dynamic hysteresis model are 0.08 μm and 0.11 μm, respectively, which are better than those of other typical models. The tracking experiments with ±400 μm/s triangle indicate that the mean error and the max error of the compound controller are 0.085 μm and 0.105μm respectively; and the tracking experiments with multiple sinusoid indicate that the mean error and the max error are 0.105 μm and 0.115 μm respectively.