Adaptive output feedback actuator failure compensation for a class of non-linear systems

An adaptive compensation control scheme using output feedback is designed and analysed for a class of non-linear systems with state-dependent non-linearities in the presence of unknown actuator failures. For a linearly parameterized model of actuator failures with unknown failure values, time instants and pattern, a robust backstepping-based adaptive non-linear controller is employed to handle the system failure, parameter and dynamics uncertainties. Robust adaptive parameter update laws are derived to ensure closed-loop signal boundedness and small tracking errors, in general, and asymptotic regulation, in particular. An application to controlling the angle of attack of a non-linear hypersonic aircraft dynamic model in the presence of elevator segment failures is studied and simulation results show that the developed adaptive control scheme has desired actuator failure compensation performance. Copyright (c) 2004 John Wiley & Sons, Ltd.