Research On Hysteresis Modeling And Precision Control Of Two-Dimensional Micro-Nano Positioning System Driven By Piezoelectric Ceramics

With the extensive application of precision manufacturing technology in more and more fields,the research on micro-nano positioning system gradually become hot in academia and industry.And the driver is an important part of the micro-nano positioning system,whose performance directly affects the output accuracy of the whole system.The piezoelectric ceramic driver among the drivers is an ideal driving element in the field of micro-nano positioning due to its high resolution,fast response and low-energy consumption.However,the voltage-displacement output of piezoelectric ceramic drivers is characterized by a non-smooth and complex nonlinear signal,which seriously affects the performance of micro-nano positioning system.In addition,there is often a coupling effect between piezoelectric actuators in two-dimensional micro-nano positioning system,which greatly reduces the output accuracy of the micro-nano positioning system,makes platform control more difficult,and limits the application range of the two-dimensional micro-nano positioning platform.Based on the above problems,this paper mainly studied the hysteretic characteristics and formation mechanism of the piezoelectric ceramic drives.Firstly,establishing the Duhem hysteresis model.The modeling accuracy was improved by dividing the hysteresis curve into the booster and buck segments for respective parameter identification.The recognition accuracy of the model parameters was improved by introducing the bat algorithm based on the artificial fish swarm algorithm.Secondly,the feedforward controllers in the x-axis direction and the y-axis direction was designed to delay the piezoelectric ceramic driver;the decoupling controllers in the x-axis direction and the y-axis direction were designed to reduce the influence of the coupling effect on the system;Finally,the composite controller in the x-axis and y-axis direction was designed to perform closed-loop control on the micronano positioning system to reduce the adverse effects of external interference factors on the system and to improve the control precision.The performance of the designed controller was tested by a series of experiments such as feedforward control,decoupling control and compound control.The specific research content of this paper is as follows:(1)The characteristics of piezoelectric ceramic actuators were researched.In-depth study of the hysteresis nonlinear characteristics,creep characteristics,frequency correlation and temperature characteristics of piezoelectric ceramics,from the three aspects of electrostrictive effect,ferroelectric effect and inverse piezoelectric effect of piezoelectric ceramic materials Explained the formation mechanism of hysteresis nonlinearity.The coupling effect between piezoelectric ceramic actuators in two-dimensional micro-nano positioning system was studied,and the characteristics of two-dimensional micro-nano positioning system were summarized and analyzed.(2)A Duhem hysteresis model was established.The hysteresis curve was divided into two parts,the boosting section and the depressing section,to identify the model parameters respectively and established a segmented Duhem model.Compared the accuracy of the model established by the two parameter identification methods,the validity of the segment identification model parameters was verified.The effectiveness of the model under different frequency voltage signals was verified by simulation experiments.(3)The parameter identification algorithm was optimized.Based on the artificial fish swarm algorithm,the acoustic wave transmitting frequency and the global optimal solution in the bat algorithm were introduced to optimize it.The accuracy of the Duhem hysteresis model established by the artificial fish swarm algorithm(AFSA)and the optimized artificial fish swarm algorithm(BAAFSA)was compared,the effectiveness of the optimized artificial fish swarm algorithm(BA-AFSA)in parameter identification was verified.(4)Feedforward controllers were designed.Based on the inverse model of the established Duhem model,the feedforward controllers in the x-axis direction and the y-axis direction were designed to compensate the hysteresis of the piezoelectric ceramic actuator.The effectiveness of the two-direction controllers were verified by the feedforward control experiment.(5)Decoupling controllers were designed.The decoupling controllers in the x-axis direction and the y-axis direction were designed respectively to reduce the negative influence on the output accuracy of the system due to the coupling effect between the piezoelectric ceramic drivers.The effectiveness of the two-direction controllers were verified by the decoupling control experiment.(6)Composite controllers were designed.The PID controller was introduced to feedback control the system,and the x-axis direction and the y-axis direction were designed respectively.The composite controllers under the action of feedforward,decoupling and feedback performs precise control on the two-dimensional micro-nano positioning system,The effectiveness of the two direction controllers were verified by the composite control experiment.