Multisensor Fusion Fault-Tolerant Control of a Magnetic Levitation System

In this paper, a multisensor fusion fault-tolerant control system with fault detection and isolation via set separation is implemented on a magnetic levitation (MAGLEV) system. Three sensors are embedded in the MAGLEV system and their measurements used by three independent estimators. A fault detection and isolation unit verifies that for each sensor-estimator combination, the estimation tracking errors lie inside pre-computed sets and discards faulty sensors when their associated estimation tracking errors leave the sets. An active fault tolerant controller is obtained, where the remaining healthy estimates are combined using an optimal fusion criterion. Theoretical results on the system linearisation around an operating point ensure local closed-loop stability and good performance under the occurrence of abrupt sensor faults. Experimental results are provided which confirm the fault tolerant capabilities of the strategy.