Observer-based Fault Tolerant Control for a Class of Lure Nonlinear Systems

In this paper, we present an invariant-set-based method for actuator fault tolerant control in Lure systems. A set-membership fault detection and isolation unit diagnoses the current fault situation by monitoring residual variables con-structed from the system measured signals. Faults are diagnosed by verifying the containment of the residual signal trajectories in sets where the residuals are shown to belong under healthy and faulty conditions. The Lure plant is controlled by an observer-based feedback tracking controller, whose parameters can be adapted to each considered healthy/ faulty scenario. Controller reconfiguration is thus achieved by engaging the controller corre-sponding to the diagnosed fault situation. We provide conditions for the stable and fault tolerant operation of the overall scheme.