Adaptive robust backstepping control for quadcopter UAV based on integral sliding mode surface

This paper proposes an integral sliding mode based adaptive robust backstepping control scheme to improve the trajectory tracking and hovering performance of a quadrotor unmanned aerial vehicle (UAV) under large-scale time-varying disturbances. It also considers the impact of variations in the payload mass of the UAV, such as in tasks such as power line maintenance or rescue operations. The proposed scheme effectively mitigates the influence of disturbances on the flight process when the upper bound of the time-varying disturbance is unknown, and estimates the potentially uncertain parameters of the system in real time. Using Lyapunov stability theory, it was proven that the designed controller ensured the asymptotic convergence of the tracking error to zero. Furthermore, this paper integrates adaptive control with the concept of integral sliding mode, combining their respective technical characteristics in a complementary manner. The proposed adaptive law, incorporating a σ-modification term, effectively suppresses the chattering inherent in sliding mode control, ensuring system stability. The integration of the sliding mode surface further accelerates the error convergence to zero. The simulation results validate the performance of the proposed control scheme in various scenarios, including continuous weak disturbances, changes in payload mass, and sudden large-scale time-varying disturbances. The results demonstrate that the proposed control scheme has strong robust stabilization and wide applicability, outperforming the traditional adaptive robust control methods and classical PID methods.