基于梯形算子的AFM驱动器非对称迟滞性校正

Asymmetric hysteresis calibration of AFM actuator based on keystone operator

原子力显微镜(AFM)通常采用压电陶瓷(PZT)作为驱动器以实现纳米尺度的观测和操作。然而,PZT自身的迟滞非线性会对AFM观测质量和操作精度产生很大影响。基于Prandtl-Ishlinskii(PI)模型的前馈控制方法可对PZT的迟滞非线性进行补偿,但传统PI模型无法消除PZT的非对称迟滞性的影响。针对这个问题,提出一种基于梯形算子的非对称迟滞模型,并可用系统辨识方法获取逆模型参数,该方法可有效实现具有非对称迟滞特性驱动器的前馈补偿控制。AFM系统实验证明,该模型可有效减小非对称迟滞性导致的建模误差,基于该模型的前馈迟滞补偿控制可有效提高AFM的扫描成像质量。

Piezoelectric（ PZT） actuator is often used in atomic force microscope to realize nano-scale observation and manipulation.However,the intrinsic hysteresis non-linearity of PZT strongly affects observation quality and manipulation accuracy. Prandtl-Ishlinskii（ PI） model based feedforward controller can compensate the hysteresis non-linearity of PZT,but the conventional PI model cannot eliminate the effect of asymmetric hysteresis. Aiming to solve the problem,an asymmetric hysteresis model based on keystone operator is proposed. Parameters of inverse model are obtained through system identification method,and the feedforward calibration is implemented based on the inverse model. Experiment in AFM system shows that modeling errors caused by asymmetric hysteresis are effective reduced by the proposed hysteresis model,and imaging quality of the custom-built AFM is improved by feedforward hysteresis compensation based on the model.