基于PI迟滞模型的压电驱动器自适应辨识与逆控制

压电陶瓷驱动器的迟滞非线性特性严重影响了其跟踪定位精度,甚至引起闭环系统失稳.本文采用经典PI模型描述压电驱动器的迟滞非线性,利用自适应投影算法对PI模型的权向量进行在线辨识,并与传统的最小二乘辨识方法进行比较.迟滞PI模型的优点是模型存在解析逆,因此本文对压电驱动器采用自适应逆跟踪控制,利用驱动器的输出位移与参考位移之差使用自适应投影算法在线辨识PI模型的权向量,并计算PI逆模型的权向量和阈值,最终得到要输入的电压值.最后实验结果表明自适应逆跟踪控制比传统的逆模型跟踪控制精度提高了49.8%.

Adaptive Identification and Inverse Control of Piezoelectric Actuators Based on PI Hysteresis Model

Piezoelectric ceramic actuators generally exhibit strong hysteresis nonlinearity effects in their output responses, which may cause inaccuracies and oscillations in the closed-loop system responses. In this paper, the classical Prandtl-Ishlinskii （PI） model is used to capture the hysteresis nonlinear- ity in the piezoelectric actuators. The adaptive projection algorithm is utilized to identify the weighting values and the identification result is compared with the least-square optimization method. The adaptive inverse controller is used to track the piezoelectric actuator considering that PI model has its analytical inverse. We first identify the weighting values of the PI model in situ using the adaptive projection algorithm based on the error between reference displacement and actual displacement of the actuator, and then calculate the weighting values and threshold values of the PI inverse model. At last, we obtain the feedforward input voltage. Experimental results demonstrate that the tracking ability of adaptive inverse controller is 49.8% higher than that of the conventional inverse controller.