Prescribed-time incremental backstepping fault-tolerant control for wing-damaged aircraft

Considering the influence of external interference and model uncertainty, a prescribed-time increment backstepping fault-tolerant control method is proposed to quickly recover the attitude angle of the aircraft when suffering the wing damage fault. First, based on wind tunnel test data, the aerodynamic characteristics of the aircraft after suffering wing-damage fault are analyzed, and the attitude angle and angular rate dynamics equations considering the change of the center of gravity are established. Second, a prescribed-time based filter is introduced, which can effectively avoid the differential explosion problem in the backstepping method. Then, a prescribed-time incremental backstepping attitude controller is designed to achieve rapid stabilization and precise control of the aircraft's attitude angle. On this basis, considering the higher-order infinitesimal terms ignored during the incremental backstepping design as well as the external perturbations and model uncertainties existing in the system, a preset time-perturbation observer is proposed to accurately estimate and quickly compensate for them, which further improves the fault-tolerance of the proposed attitude controller. It is proved by strict Lyapunov stability that the proposed controller can achieve stable control of the attitude angle within the user-defined time, which is independent of the initial state of the system and the parameters of the proposed controller, and simplifies the process of adjusting the parameters against the convergence time. Finally, numerical simulations verify the effectiveness of the proposed method.