Nonlinear control of a magnetic bearing system

A nonlinear control system for a magnetic journal bearing is designed using a combination of feedback linearization and backstepping concepts, and is implemented with a floating-point digital signal processor. Position control, tracking control, and gain sensitivity experiments demonstrate improved accuracy and greater stability margin than that achieved using present industrial practice. The closed-loop response is very easily tuned using the proposed nonlinear approach, and the nonlinear controller uses significantly less current than a linear controller because no bias currents are required in the electromagnets. (C) 2002 Elsevier Science Ltd. All rights reserved.