Fault-tolerant output-feedback control via fuzzy state blending

A fault-tolerant scheme for sensor faults in output-feedback control is developed by using standard linear design methods combined with try decision logic and ´soft´ reconfiguration based on fuzzy state blending. The main advantages of the presented method are the use of standard deterministic control-oriented observers without the need to design special diagnostic observers for the different faults, and the simplicity and transparency of the decision logic. The control scheme is tolerant with regard to total and partial sensor faults occurring separately or simultaneously (under certain specified conditions). The decision logic gives information both on the localization of the fault and its severity. Experimental real-time results are presented for a laboratory system.