Sensor fault‐tolerant control of a magnetic levitation system

In this paper, a fault-tolerant switching control strategy is implemented on a magnetic levitation (MAGLEV) system. Two sensors are embedded in the MAGLEV system and their measurements used by two independent estimators. Each sensors–estimator combination, together with a feedback controller can levitate and stabilize a 1-in steel ball at a desired position in the air. The paper focuses on the design and testing of a switching scheme which, at each instant of time, selects the sensors–estimator combination that provides the best closed loop performance based on a chosen criterion. Theoretical results on the system linearization around an operating point ensure local closed-loop stability and good performance under the occurrence of an abrupt fault in one of the plant sensors. Experimental results are provided which confirm the fault-tolerant capabilities of the strategy. Copyright © 2010 John Wiley & Sons, Ltd.