Study on the sliding mode control system for air gap of electrical Maglev based on the feedback linearization

Air gap control of electrical Maglev system has the characteristics of strong nonlinearity and instability. In order to realize the air gap control, the current-PID control of the electrical magnetic coil was widely used in the traditional method, with the help of linearizing the local area around the balance point, adjusting the pole points, and observing or filtering the states.The above-mentioned theoretic methods were strictly limited under the precondition of the linear subsystem without any parameter-change and the occurrence of any disturbance. Because of the obvious traits of parameter-changing and multi-disturbance of actual Maglev system during the working time, the descending of control characteristic, even the invalidation of control strategy were probably induced by the traditional control way. Based on sliding mode control with the feedback linearization, a kind of non-linear control strategy of electrical Maglev air gap was offered, the design method of the system was researched. The results of simulation showed that the designed air gap system with the feedback linearized sliding mode controller has quicker respond, excellent ability of anti-disturbance, and adapts to real-time system.