Non-singular predefined time sliding mode control for quadrotor UAV with actuator fault

Aiming at the problems of unknown disturbances and actuator failures during the flight of quadrotor unmanned aerial vehicle (UAV), a non-singular predefined time sliding mode controller is designed for quadrotor UAV with actuator failures. Firstly, the actuator failure model is analyzed, and the quadrotor UAV with failure model is constructed. Secondly, the uncertain terms, external disturbances, and actuator failures are regarded as lumped disturbances, and the predefined time disturbance observer is designed to estimate the lumped disturbances. The designed observer can ensure the tracking of the lumped disturbances within the predefined time. Finally, a non-singular predefined time segment sliding surface and an improved segmented exponential convergence law are designed. The proposed sliding surface avoids the singular problem caused by the traditional predefined time sliding surface, while the segmented exponential convergence law suppresses the chattering of the control input. The stability of the designed observer and controller was proved through Lyapunov theory. The simulation experiments show that under the proposed control method, the tracking performance of the quadrotor UAV can complete convergence within the predefined time. Meanwhile, during the actuator failure period, the proposed control method outperforms the traditional predefined time sliding mode control and non-singular terminal sliding mode control in terms of robustness.