Self-tuning Fuzzy Pid Controller Based On Ga In The Application Of Magnetic Levitation Ball System Research

Magnetic levitation technology is the key technology of magnetic levitation train, magnetic bearing and magnetic motor and so on. Due to its many merits such as no mechanical friction, no wear, long longevity, low power loss, and no noise, it has become an attractive field of the current control research domain.The Magnetic Levitation Control System is an important platform of magnetic levitation technology studies. Due to the characteristics of essential nonlinear, uncertainty and open loop instability, it is hard to control the system using the traditional control methods. On the basis of the understanding on the characteristics of magnetic levitation system and the relevant research work both in abroad and at home, this paper seeks to improve the overall performance of the Magnetic Levitation System.Firstly, this thesis established the Magnetic Levitation Control System’s mathematical model according to each constituent’s physical principle, and analyzed the linearization characteristics of the nonlinear mathematical model nearby the balance point. Then, contraposing the feather of the complex nonlinearity, the paper introduces the features of classic PID control and fuzzy control, and combine the two algorithm each other to form a fuzzy PID controller of the Magnetic Levitation System.Then, aiming at the shortage of the fuzzy PID control, the self-tuning fuzzy PID control algolithm based is presented by introducing the self-tuning method of the scale factors, so that the scale factors of the fuzzy controller changes with the control criteria. By combining this control method and the optimization algorithm, the genetic algorithm is used to optimize the parameters of flex factors. This self-adjusting control method can adjust the control parameters on-line according to the change of the dynamic performance of the system, so as to achieve the purpose of optimizing the controller. The control simulation to the Magnetic Levitation System is done in Matlab in order to verify the control performance of the controller.Finally, the real-time control experiment is done in the magnetic levitation device. The result of computer simulation and the real-time control experiment shows that the self-tuning fuzzy PID controller has superior control performance in both dynamic and steady aspects and has good control performance for the nonlinear system such as the Magnetic Levitation System.