Robust Position Tracking of Magnetic Suspension System Using the Sliding Mode Controller based on Inertial Delay Control

Magnetic suspension system as an appropriate mechanism for non-touch maintaining the objects through magnetic force has become very important in many applications. Due to their instability and high nonlinearity, such systems pose a challenge to many researchers attempting to design high-performance and robust tracking control. This paper proposes a sliding mode control strategy for a nonlinear magnetic suspension system with one degree-of-freedom. In conventional sliding mode control systems, insensitivity to uncertain parameters and external disturbances is achieved when the bounds of the uncertainty and disturbance are known. In this regard, the proposed control structure is the inertial delay control being concentratedly estimated the uncertainties of the system and unknown disturbances. The main purpose of this paper is to implement the robust output tracking through centralized uncertainty and its estimation in which, by considering the suspension system coil current as the control input, the position of the suspended object is maintained and the estimation error tends to zero. Simulation results indicate the designed controller on the magnetic suspension system has a good performance compared to the other methods. In addition, the proposed method is effective and the output robust tracking, as well as the estimation of system uncertainties, are realized.