Practical Test for Closed-Loop Identification and Control on Magnetic Levitation System: A Fractional-Order Approach

Magnetic levitation system is an interesting equipment to demonstrate an intricate control design problem. Because of its non-linearity and exhibit uncertain open-loop properties together critically unstable in nature, identifying such system and then designing an effective controller is very demanding. This paper proposes identification and control strategy for real-time magnetic levitation system based on fractional theory and an orthogonal series. Without removing the controller from the loop, the unknown system is identified in form of low-order fractional model accurately. Then, a new fractional controller namely FOPID (fractional-order-proportional-integral-derivative) is tuned to improve the system performance. Real-time experiment study clearly illustrates the effectiveness of the presented tuning method.