Reduced-order fault estimation observer based fault-tolerant control for switched systems

This paper studies the fault-tolerant control (FTC) problem for switched systems with actuator fault. The reduced-order observers based method is proposed to reconstruct the system state and fault, simultaneously, where the fault can be large and fast time-varying. If the disturbance is ignored, the exponentially stable estimation result can be achieved. Furthermore, the FTC strategy is considered to stabilize the systems. Under any switched law, the root-mean-square (RMS) gain is considered to realize the robustness of the discussed technique to the disturbance. Compared with the traditional H-infinity performance, it not only relaxes the limitation of disturbance being with bounded energy, but also removes the requirement of zero initial condition. In the fault estimation process, the zero initial condition requires the state and fault initial values should be known, which is not needed in this paper. At last, the effectiveness of the considered technique is verified by two examples.