An Adaptive Robust Scheme for Multiple Actuator Fault Accommodation

In this paper, we solve the problem of output tracking for linear systems in presence of unknown actuator failures using discontinuous projection based output feedback adaptive robust control (ARC) scheme. The faulty actuators are characterized as unknown inputs stuck within certain bounds at unknown instants of time. This problem is of prime importance for safety critical missions like flight control system. Many existing techniques to solve this problem use model reference adaptive control (MRAC), which is not well suited for handling various disturbances and modeling errors inherent to any realistic system model. In comparison, the backstepping based output feedback ARC approach used here can effectively deal with such uncertainties. Simulation studies are carried out on a linearized Boeing 747 model, which shows the effectiveness of the proposed scheme. Furthermore, we compare our simulation results with that of MRAC in presence of disturbances, which clearly illustrates the superior performance of the proposed ARC based actuator fault compensation scheme.