Techniques For Modeling And Controlling Of Piezoelectric Actuators

Piezoelectric actuators are widely used in the nano– positioning technology, but its usage is influenced by its nonlinear property. Although through control method can reduce the nonlinear error to some extent, mostly control method has more parameters needed to be confirming that gives the difficulties to the application of piezoelectric. Based on the piezoelectric actuators and PID controller, this paper gives the controller design method on optimization. The outline is piezoelectric actuator modeling, PID optimize design and analysis.During modeling, static modeling and dynamic modeling are established for piezoelectric actuators PPA80L respectively. Static model also called hysteresis model because it is mainly describe the hysteresis phenomenon. Universal hysteresis model is Preisach, Prandtl– Ishlinskii, Bouc– Wen and Wiener models, which details are given out. Dynamic model is established from Newton`s second law. It can be easily convert to transfer function and easy to analysis.Due to the parameters of PID controller are difficult to be confirmed, this paper proposes a PID controller design which use optimization method. At first is the optimize algorithm chooses. In this paper, choose the Particle Swarm Optimization Algorithm which has more advantages like simple in algorithm thinking, fast in optimize speed, not easily go to local optimal regional, etc.. The second is the fitness function chooses. Fitness function is important in optimize process because which directly encourages the direction of the optimal solution. In this paper, the fitness function is established from the time domain features of the typical second order models whose damping coefficient is 0.707. To get the evaluate effect, using 14 objects to test and the consequences show that the fitness function has very good evaluate effect compare to ITAE and ISTSE.After choose the optimization algorithm and the fitness function, give the PID controller optimization design for piezoelectric actuators. The result clearly shows that the PID controller optimization method proposed in this paper is feasible.