Nonlinear control of a magnetic levitation shaft by numerical inversion of its behavioral model

This paper deals with the stabilization of a magnetically-levitating shaft using a simple, fast, nonlinear discrete time control approach. The proposed control approach uses an approximate numerical one-step time discretization of the nonlinear plant model behavior obtained from offline simulations. Using that discretization, a control minimizing the distance between the plant output and a reference linear system is computed, leading the system to adopt its dynamical behavior. Since the prediction horizon is limited to one time-step, the execution time of the algorithm can be completely bounded. It can thus easily be implemented and used to control fast electromechanical systems. Experimental results obtained from a laboratory device show the performance and robustness of the proposed controller.