Nonlinear control of a magnetic levitation system

In this paper the identification, analysis, design and implementation of a controller for the ECP730 magnetic levitation system is presented. The system model, which presents interesting structural properties reported here for the first time, is nonlinear and hence a feedback linearization approach is used. In addition, an external control loop with an integral factor is used to achieve zero steady state error. Due to the nonlinear nature of the static friction and the integral factor, the control system presents a stick-slip behavior. In order to eliminate such effect in the steady state, a switching controller is implemented. This approach switches between a linear controller with and without integral factor. Real time results showing the control system performance are included.