IBLF-Based Fixed-Time Fault-Tolerant Control for Fixed-Wing UAV With Guaranteed Time-Varying State Constraints

Abstract

This paper proposes a novel adaptive fixed-time fault-tolerant control method for the fixed-wing unmanned aerial vehicle (UAV) subject to asymmetric time-varying full state constraints. The UAV nonlinear dynamics of six-degree-of-freedom (6-DOF) with twelve-state-variables is considered in this article, rather than only longitudinal/lateral or attitude dynamics in most existing results. A novel Integral Barrier Lyapunov Function (IBLF) is applied for the first time to solve the control problem of the UAV with the asymmetric time-varying full state constraints, which reduces the conservativeness of the conventional IBLF-based method. Furthermore, a continuous switching function is introduced to solve the singularity problem which typically appears in the fixed-time control methods when tracking errors approach to zero. It is rigorously proved that all the states are forced in the asymmetric time-varying bounds and the tracking errors of velocity and attitude converge to a residual set around origin within fixed time. Finally, the simulation results are given to validate the effectiveness of the proposed scheme.