Research On Sliding Mode Variable Structure Controller Of Active Magnetic Bearing

With the development of industry, the traditional bearing is more and more difficult to satisfy the requirement of high performance and low energy loss. It is important to explore new alternative bearing. Active magnetic bearing has many advantages, such as no mechanical wear, no friction, no lubrication, low noise, controllable rigidity damping, high speed and so on. It has become the ideal substitute of traditional bearing. But, active magnetic bearing system is a multiple input multiple output system with nonlinear, high coupling. Using the traditional PID control method cannot meet the requirements of stability and dynamic characteristic. Therefore, this article adopts sliding mode variable structure control strategy to study the controller of active magnetic bearing. The main work is as follows:This paper summarizes the development status and application prospect of active magnetic bearing, studies the basic structure and working principle of active magnetic bearing.By the researching of single degree of freedom active magnetic bearing system, the mathematical model is established. Based on the discrete sliding mode variable structure control theory, the controller is constructed. Using the MATLAB program, the effects of discrete sliding mode variable structure controller and traditional PID controller are simulated.On the basis of the research on the single degree of freedom magnetic bearing, the five degrees of freedom active magnetic bearing system is studied, and its mathematical model is established. The complexity and the decoupling method of the five degrees of freedom active magnetic bearing system is analyzed. A controller based on MIMO integral sliding mode variable structure control is designed. Finally, the simulation results show that the proposed control strategy has better dynamic performance and robustness than the traditional PID control method.