This paper presents a new actuator fault accommodation based on a hybrid of static and dynamic redundancies. Introduction of the activation functions for the actuators makes it possible to switch the redundancy modes appropriately. These functions are switched among the two values, 0 and 1, by monitoring only the input and output signals, and they determine the power supplies for the actuators. Furthermore, in this paper, the adaptively switching high-gain feedback controller is developed to achieve the ?-tracking in the presence of unknown perturbations. The adaptive tracker is modified to suit the switching mechanism for tuning the activation-functions. Thus, the proposed adaptive fault-tolerant control system with a hybrid redundancy has the advantages of both static and dynamic redundancies, and has high robustness with regard to actuator failures and variations in dynamics. In addition, a practical application to a chemical reactor is shown to confirm the effectiveness of the overall adaptive fault-tolerant control system. (c) 2012 Curtin University of Technology and John Wiley & Sons, Ltd.
