扫描隧道显微镜扫描器的迟滞非线性控制
Control of Hysteresis Nonlinearity for Scanning Stage in Scanning Tunneling Microscope

压电驱动器被广泛应用于扫描隧道显微镜（scanning tunneling microscope,简称STM）的扫描器，但压电材料本身的迟滞非线性特性影响了STM的扫描精度。为了补偿由于迟滞非线性带来的扫描器控制误差，提高STM的扫描精度，基于迟滞非线性模型，设计了前馈控制器，并与PID反馈控制相结合。利用所设计的控制器进行了扫描实验，并与位移反馈控制扫描进行对比。实验结果表明，采用位移反馈控制时光栅周期相对测量误差和光栅线宽相对测量误差分别为4.41%和2.65%，采用迟滞逆模型与PID反馈的复合控制后，光栅周期相对测量误差和光栅线宽相对测量误差分别减小到1.26%和0.27%，迟滞引起的非线性误差得到了补偿，减小了扫描器控制误差，提高了扫描精度。
Piezoelectric actuators have been widely applied in scanning tunneling microscope (STM). A controller combining inverse hysteresis model and PID control law was designed for the STM to compensate for the hysteresis nonlinearity of piezoelectric actuators and to improve the scanning accuracy. For the purpose of comparing the proposed controller with classical displacement feedback control law, experimental system was built in this investigation. The relative measuring error of grating period and width of grating line were 4.41% and 2.65% using the classic displacement feedback control method respectively. And they were reduced to 1.26% and 0.27% in proposed method. Experimental results indicate that the error caused by hysteresis nonlinearity has been well compensated, and the scanning accuracy is improved with the help of such controller.