Design Of Piezoelectric Ceramic Model With Fast Response Based On Feedforward Control Algorithm

At present,the space optical communication technology has been paid more and more attention,the United States,Europe,Japan and other countries have carried out research on satellite laser communication.Compared with microwave communication,space optical communication has the advantages of high transmission rate,good directional performance,large communication capacity,good security and low power consumption.Aiming,acquisition and tracking technology,or PAT technology,is an important technology in space laser communication.Its main function is to capture beacon light and maintain the stability of communication link.The precision sight is an important part of the aiming,capturing and tracking system.The precision of the precision sight affects the tracking and pointing accuracy of the whole system.Piezoelectric ceramics have fast response speed,high control precision,simple structure and small occupied space,but at the same time,piezoelectric ceramics also have hysteresis,creep and dynamic characteristics,which will disturb the output to some extent,the hysteresis has the greatest influence on the output displacement,and the maximum error is 15%.As the hysteresis of piezoelectric ceramics will seriously affect the precision of tracking and aiming,it is necessary to compensate the hysteresis of piezoelectric ceramics.In this paper,the modeling and control methods of piezoelectric ceramics at home and abroad are studied,the working principle of PAT system is analyzed,the basic components of fine scope are introduced,and the internal mechanism of piezoelectric ceramics is analyzed.The classical P-I model was selected to build the model,and the P-I hysteresis model was improved to solve the asymmetry of hysteresis curve of piezoelectric ceramics.Based on the improved asymmetrical P-I hysteresis model,the inverse hysteresis model is derived and the parameters are identified.The piezoelectric ceramics hysteresis is compensated by the feedforward control algorithm,the simulation results show that the feed-forward control algorithm can effectively compensate the hysteresis of piezoelectric ceramics.Finally,the feedforward control is combined with PID control,and the output precision and step response time of piezoelectric ceramics under the compound control of feedforward and PID are verified by Matlab simulation,the combination of feedforward and Pid control improves the control accuracy,but the response time is not as fast as the open-loop feedforward control.Based on the hybrid control of feedforward and Pid,a creative method is proposed to improve the step response time of piezoelectric ceramics,the open-loop control is used to give the piezoelectric ceramics a large impact force,and then the time is controlled by the feedback closed-loop control,so as to ensure the stability of the system and improve the step response time.The simulation results show that the step response time can be greatly improved and the control accuracy can be guaranteed by switching the signal to the closed-loop control when the output value reaches 80% of the maximum.