The Piezoelectric Actuator Device Modeling And Nonlinear Control

The dissertation derives from the project"Piezoelectric platform for precision positioning using charge-feedback and nonlinear control method"supported by National Natural Science Foundation of China (authorized No. 10376043). According to the contract, a two dimensional micropositioning platform with small creep and hysteresis behavior and with high linearity was developed in this paper. The platform is widely applied in precision engineering, ultraprecision machining and et al, which consists of a mechanical elastomer, two piezoelectric actuators, two driving circuits based on charge-feedback, two linear variable differential transformers, and a numerical control device based on C8051F021.In order to deal with the nonlinearity and hysteresis of piezoceramics, a precise power amplifier circuit with charge-feedback loop was developed. And an electromechanical model of piezoelectric actuator is presented to demonstrate that charge-feedback control is prominently effective to reduce hysteresis, creep and to improve linearity. Furthermore, in order to enhance the precision and linearity of the positioning platform, simulations of several numerical control algorithms, such as PID control, fuzzy control and NN (Neuro Net) had been carried out. The results show that fuzzy PID control has better performance than the others. Compared with the piezoelectric actuator using voltage-feedback control procedure, the nonlinearity of the platform is reduced by 60%, and the hysteresis and the creep are reduced by 95% or more.