Study On Variable Structure Control Of Magnetic Levitation System

Magnetic suspension has been paid more and more attention because of its many merits such as no mechanical contact, no wear, low power loss, no need of lubrication and long service life, etc. The performance of magnetic suspension is determined mainly by its control system. Therefore, so it has great significance to study control method of suspension system. It is difficult for a magnetic suspension system with traditional method to solve the problem of the uncertainties caused by the parameter variety and disturbance. And variable structure control method has fast response and system parameter perturbation and external interference by the invariance properties of great importance to scholars. Therefore, this article focuses on variable structure control theory in the magnetic levitation system.This article introduce the maglev system composition and working principle, and analyzes the system is unstable and non-linear characteristics. The traditional control linearizes the system partially in the balance point nearby mostly, when the disturbance is too big, it will make the system deviate a balance point far away, resulting in the controller deteriorating quickly and influencing the system's stabilization possibly. So in this article make use of singular perturbation method ascertain nonlinear control system model of the magnetic levitation system.Although the variable structure control method is rapid, robustness and easy implementation, etc., but they are bring to high-frequency buffeting of control signal and the buffeting not only affects the accuracy and increase the capacity of consumption, even such high-frequency input very easily give rise to systematic unmolded characteristics, thereby undermining the performance of the system. This paper, integral sliding surface design of the switch function, and combined with the method of adaptive control and sliding mode control, adopt adaptive strategies to estimate the uncertain system parameters, use the estimated parameter values and the conditions of sliding mode to design control input. Through the simulation results indicate that the algorithm reduce the uncertainty, and has smaller control gain. On the condition of without affecting the steady-state performance, effectively weakening the system buffeting and ensure the sports state of system can track the desired trajectory, and improve the smooth control law of the unknown dynamic characteristics of robustness.