Adaptive fault tolerant attitude tracking control for miniature rotorcrafts under actuator saturation

The problem of attitude tracking control for a miniature rotorcraft with partial loss of actuator effectiveness is investigated in this paper. By using adaptation mechanism and by combining with Nussbaum gain technique, an adaptive tolerant control strategy capable of attenuating immeasurable disturbances, compensating system parameters uncertainties, and accommodating actuation faults is developed. Then, the rotorcraft attitude system subjected to control constraints is further considered, and a novel fault tolerant controller equipped with auxiliary systems is designed to achieve both attitude tracking and saturation alleviation of control signal. Moreover, fault detection and diagnosis unit are not needed in using and implementing the proposed method. It is proven that attitude errors can asymptotically converge to a small neighborhood of equilibrium point in the face of faulty actuator, model uncertainties, external disturbances and even actuator saturation. Finally, the simulation results demonstrate the effectiveness of the proposed controller.