Observer-based fault reconstructions and fault-tolerant control designs for uncertain switched systems with both actuator and sensor faults

This study considers the problems of the simultaneous estimations of the states, actuator and sensor faults and the design of observer-based fault-tolerant control (FTC) for a class of uncertain switched systems. First, by treating the system state, actuator fault and sensor fault as an augmented state vector, a descriptor system is constructed, where the output equation contains no faults in form. Second, the relationships between the preconditions of the original system and the descriptor system are investigated in detail, under which a reduced-order observer, which can estimate the original system states, actuator faults and sensor faults simultaneously without suffering from the influence of the disturbance, is developed. Third, based on the state estimations given by the reduced-order observer, a state-fault feedback fault-tolerant controller is designed based on an optimising H-infinity performance index and the gains are computed by linear matrix inequalities (LMIs). Finally, an electrical circuit example is given to show the effectiveness of the proposed methods.