抄録
This paper presents a nonlinear control of a magnetic levitation system for a flexible beam. There are few papers treated magnetic levitation systems for flexible objects. In most of these researches controllers are designed without explicit consideration of dynamics of flexible objects or are designed based on mode-decomposed dynamics of flexible objects in which high order modes are truncated. And also non-linear dynamics is approximated into linear models in a neighborhood of an equilibrium point. These linear finite order controllers cannot compensate large levitation gap and cause spillover phenomenon. In this paper, the dynamics of the flexible object are fully addressed and the results are valid for large deviations from equilibrium. The magnetic levitation system is divided into two subsystems: an electrical subsystem and a mechanical subsystem. The controller for each subsystem is designed independently based on passivity. The resulting controller dose not needs current feedback for the electrical subsystem while using position, velocity and deflection rate feedback for the mechanical subsystem. It ensures asymptotic stability of trajectory tracking and suppression of elastic vibrations. To illustrate the validity of our controller, some numerical simulations are carried out.
