Application Of Fuzzy Control For The Magnetic Levitation System

Magnetic levitation is a technology which integrates several technologies such as electromagnetics, mechanics, control engineering and computer, etc. Due to its many merits such as no mechanical friction, no wear, long longevity, low power loss, and no noise, it has become a hotspot issue in the scientific community of the world. However, it is difficult to build its mathematical model because of its inherent nonlinearity, instability, as well as the problem of uncertainties caused by disturbance of the traditional magnetic levitation control system. These factors make the control using the traditional control methods more difficult.Comparing with other intelligent control methods, fuzzy control does not require the precise mathematical model of the system. And for the nonlinear system or the system that have uncertain description in the input or operating, it has good dynamic performance and good adaptability when the parameter changes. So it is very suitable for the system that has uncertain mathematical model and complex nonlinearity.According to the feather of the nonlinearity and time-varying, this thesis focuses on the research about the application of the fuzzy control and its self-adaptive method in the magnetic levitation system. Firstly, on the basis of the research on the traditional PID control and fuzzy control alone, and according to the analysis about the internal relationship between the traditional fuzzy control and PID control, the advantages and disadvantages of the two methods, the PID parameter fuzzy self-modified control is presented. Then, because of the limitation of the fuzzy control, the scaling factors self-modified fuzzy control is presented by combining fuzzy control and optimization algorithms. These two self-adaptive control methods can adjust the control parameters on-line according to the change of the dynamic performance of the system. It is beneficial to control the system accurately and attain better performance. Finally, the real-time control experiment is done in the Matlab software in order to verify the control performance and self- adaptive ability of different fuzzy controller.The real-time control experiment proves that the algorithms proposed in this thesis are more flexible, adaptable and has good controlperformance for the stability and dynamic of nonlinear complex systemsuch as magnetic levitation system.