Modeling And Control Of Piezoelectric Ceramic Actuator Based On LS-SVM

Piezoelectric ceramic actuators are widely used in the field of precise positioning in industrial production for it's advantages in fast response,good piezoelectric effect and high motion accuracy.But its inherent rate-dependent hysteresis nonlinearity seriously weakens the control accuracy of the system,even makes the system lose stability,which has a serious impact on its development in the engineering field.Therefore,in this paper,the piezoelectric ceramic actuator as the research object,has carried on the following aspects of research:1?Aimed at the dynamic hysteresis nonlinearity of piezoelectric actuator,a hysteresis model based on least squares support vector machine(LS-SVM)is established.In the process of modeling,the sinusoidal sweep signal is used to excite the actuator's modes at different frequencies.The model test results show that the model is suitable for hysteresis loops under single frequency and compound frequency excitation,and the accuracy of the model is high.2?Based on the LS-SVM hysteresis model,the LS-SVM method is also used to establish the inverse model of the actuator,and the feed-forward inverse+ PID feedback composite controller and internal model controller are designed respectively.The real-time tracking control experiment is carried out by using the experimental system constructed on the d SPACE platform.The experimental results show that the two control methods can effectively reduce the hysteresis characteristics and achieve effective tracking of piezoelectric actuators.3?A Hammerstein-like rate-dependent hysteresis model for piezoelectric actuators is established.In the model structure,the hysteretic nonlinear part is represented by LS-SVM model and the dynamic linear part is represented by ARX model.Finally,the accuracy of the model is verified by comparing the model output with the experimental output at different frequencies.4 ? Based on the Hammerstein-like rate-dependent hysteresis model,an internal model controller and a composite controller based on PID feedback aredesigned.The real-time tracking control experiments of the two control schemes are carried out through the experimental system.The experimental results verify the accuracy of the control scheme.