Implementation and Nonlinear Stabilization of a MIMO Magnetic Levitation System

This paper presents the implementation of a three degree-of-freedom magnetic levitation system. First the dynamic model of the magnetic levitation is developed. Then based on the nonlinear model, a robust nonlinear double-loop control algorithm is applied to stabilize the system. The double-loop control architecture consists of two components: 1) terminal sliding mode control (TSMC) is employed in the outer loop to stabilize the rigid dynamic model while maintains robustness.2) Auto disturbance rejection control (ADRC) is applied in the inner loop as a current loop controller to track current command. Finally, experimental results are presented to illustrate the performance of the system dynamic response and current response in each coil. The experiment results show that the terminal sliding mode algorithm combined with auto disturbance rejection control algorithm is effective in the nonlinear MIMO magnetic levitation system.