Fault tolerant control of unstable LPV systems subject to actuator saturations using virtual actuators★

An active fault tolerant control (FTC) strategy for open-loop unstable linear parameter varying (LPV) systems subject to actuator saturations and faults is proposed in this paper. At first, the nominal controller is designed using a direct approach that takes into account the actuator limits. Later, virtual actuators are added to the control scheme, such that the faulty plant is reconfigured, and the fault is hidden from the controller point of view. Conditions for designing the virtual actuator gains are designed, aiming at guaranteeing that if at the fault isolation time the closed-loop system state is inside a region defined by a value of the Lyapunov function, the state trajectory will converge to zero despite the appearance of faults within a predefined set. The theoretical results are demonstrated using a numerical example.