Research on the Control and Remedy of Nanopositioning Stage Drived by Piezo Material Lead Zirconate Titanate
|School||Harbin Institute of Technology|
|Course||Instrument Science and Technology|
|Keywords||piezoelectric actuator PID control NN control system identification|
The piezoelectric actuator is a perfect micro-positioning drive element and is widely used with its merits of small size, light weight, high precision and high frequency response etc. However the device driven by piezoelectric actuator shows strong hysteresis, creep and nonlinearity so that it has low tiny-orientation precision and long time to reach stabilization.The thesis will have a research on the control and remedy of micro-positioning stage driven by piezoelectric actuator.A suit experiment system is firstly designed including a micro-positioning stage driven by piezoelectric actuator,power for the piezoelectric actuator,tiny-displacement transducer and data acquisition card etc.A study of work principle and traits of the piezoelectric actuator are done on the system.A kind of PID controller base on NN(neural network) of optimized BP (back propagation) arithmetic is designed in the thesis.Based on the principle that closed loop system could weaken or eliminate the three intrinsic errors,the method uses the abilities of calculate and adaption of NN to realize the control and remedy of micro-positioning stage driven by piezoelectric actuator.The control arithmetic includes two NN-NNC and NNI.The conventional PID controller is replaced by the self-study controller of NN of three-layer structure for gathering and optimizing the samples.The arithmetic of BP is used for the training of NNC on line and the training of NNI off line.The thesis could control the stage driven by the piezoelectric actuator intellectively on the base of parameters self-tuning of NNC and NNI on line.The controller is imitated and validated the feasibility of the controller in theory with the help of Matlab.The experiments of NN arithmetic and traditional PID arithmetic are separately tested based on Microsoft Visual C++ 6.0 programme in a closed loop system.The results of experiment indicate that the controller is better than traditional PID controller obviously.The results of experiment testify that adopting PID controller based on NN of optimized BP arithmetic could conquer deficiencies of strong hysteresis,creep and nonlinearity displacement of piezoelectric actuator using the closed loop tiny-displacement system and realize the real-time control stably as well as high precision.