OBSERVER-BASED FEEDBACK LINEARIZING CONTROL OF AN ELECTROMAGNETIC SUSPENSION

This paper develops a stabilizing observer-based feedback linearizing controller for a single-axis electromagnetic suspension. The controlle r uses only the measured output of the system, and is shown to be robu st with respect to parameter uncertainty. The controller differs from other robust feedback linearizing controllers that have appeared in re cent literature, because it is continuous, and non-adaptive. Lyapunov' s second method is used to prove stability and robustness of the contr oller. The controller has a simple structure and its gains are determi ned by solving two weakly coupled Riccati equations. Numerical simulat ions are performed to compare a lineal feedback controller and the obs erver-based feedback linearizing controller. Results obtained demonstr ate that the nonlinear controller yields superior performance when com pared with the linear feedback controller. The controller synthesis te chnique developed in this paper is applicable to other fully feedback linearizable systems, not just electromagnetic suspensions.