Robust Path Following Control Via Command-Filtered Backstepping Scheme

This paper presents a robust path following control law that enables a fixed-wing UAV to track a reference path under the wind disturbance. The proposed path following control law combines the kinematic control law for regulating the distance error to the moving reference point and the command-filtered backstepping scheme for obtaining the roll command of the UAV. Unlike the conventional backstepping scheme, the command-filtered backstepping scheme avoids the numerical differentiation to compute the filtered derivative of the desired course angle command, which increases the overall system robustness. Along with the rigorous theoretical proof, the performance of the proposed control law is evaluated via the hardware-in-the-loop simulations and the flight tests. The experimental results show that the improved tracking performance as well as the enhanced robustness, proving the applicability of the proposed algorithm in the various mission of the fixed-wing UAV in wind disturbance environment