Robust output tracking of nonaffine magnetic suspension system

This paper considers the robust output tracking probem for an uncertain magnetic suspension system with coil current as the control input. The state-space equations of this system have nonaffine quadratic polynomial structure. A novel sliding mode controller is designed for output tracking of a time-varying reference signal which can conquer the uncertainties and guarantees the asymptotic convergence of the system output toward the desired time-varying reference signal. Computer simulations show the efficiency of the proposed method in output tracking for this nonaffine quadratic polynomial system.