Research On Hysteresis Modeling And Control Of Piezoelectric Ceramic Displacement Platform

Piezoelectric ceramic fretting displacement platform has the advantages of zero friction,no noise,no lubrication,compact structure,strong load capacity,high resolution and fast response speed,and is widely used in biomedical engineering,precision mechanical manufacturing and other fields.However,the piezoelectric ceramic material itself has hysteresis characteristics,which will reduce the positioning accuracy of the displacement platform.For solving the influence of hysteresis nonlinearity on the positioning accuracy,the hysteresis nonlinearity of the piezoelectric ceramic displacement platform is corrected by using the composite control method of inverse model compensation and PID.The specific work is as follows:The micro mechanism of displacement caused by piezoelectric ceramics is analyzed.In view of the hysteresis phenomenon that the curve of the step-up stage and the step-down stage of piezoelectric ceramics does not coincide,the causes of the hysteresis of piezoelectric ceramics are studied,and the law of domain turnover in the applied electric field is explored.This paper introduces the hysteresis modeling method and control method to solve the hysteresis problem,and compares the advantages and disadvantages of common hysteresis models and their application scope.A piezoelectric ceramic displacement platform system is designed and built to collect hysteresis data and verify the piezoelectric ceramic control method.The system includes several modules: piezoelectric ceramic control execution module,capacitive sensor displacement monitoring module,signal processing and data acquisition module,clamping fixed mechanical structure module.Using LabVIEW and MATLAB mixed programming,the platform drive control,complex controller design,displacement monitoring and signal processing,data acquisition and storage,human-computer interaction and other functions are realized.The discretization model expression of the Duhem hysteresis model is deduced,and the intelligent particle swarm algorithm is used to identify the piezoelectric ceramic hysteresis model,thereby obtaining the best parameters of the Duhem model.Comparing the results of Duhem model fitting and polynomial model fitting,the effect of Duhem model fitting is better,which verifies the validity of the built model.A feedforward controller based on hysteresis inverse model and a PID compound controller based on feedforward compensation are designed,and the motion trajectory tracking experiment is completed.The results show that the feedforward controller based on inverse model can compensate the hysteresis effectively.Based on this,PID compound control further improves the anti-interference ability of the system and reduces the high dependence of feedforward control on the model.a composite control method based on inverse model compensation reduces the nonlinearity by 86.54% in the 0-80μm displacement range control,which greatly eliminates the hysteresis nonlinearity of the piezoelectric ceramic displacement platform and effectively improves the control accuracy.