An active fault tolerant control for a class of time delayed singularly perturbed systems

In this paper, an active fault tolerant control (FTC) scheme is suggested for the time delayed singularly perturbed systems (SPS). The considered sensor fault only affected at the systems' steady state. The time delayed SPS are decomposed into delayed slow subsystem (SS) and fast subsystem (FS) firstly. Then the fault tolerant controller for SS consists of a feedback controller and an additive term is proposed, which can compensate the sensor fault. The states and fault estimation can be realized by a delayed Luenberger observer. The feedback controller gain for FS is derived by classic pole placement method Sufficient conditions for ensuring the control law stability as well as the estimation error convergence of the observer are given employing the LMI framework. Finally, using the principal of composite control, the global fault tolerant controller for delayed SPS is derived by combining SS controller with an additive term and FS controller.