Robust optimal control for unmanned aerial vehicles' three-dimensional trajectory tracking in wind disturbance

This paper presents a robust optimal guidance control law for precise three-dimensional (3D) trajectory tracking of an Unmanned Aerial Vehicle (UAV) in wind disturbance. The wind disturbance is considered in the UAV's kinematic model. The reference path is considered as a trajectory of a virtual target. Feedback linearization is used to transform the nonlinear dynamics of the UAV to linear state equations. Based on the assumption that the wind disturbance can be known precisely, an optimal control law is derived for the UAV's 3D trajectory tracking using the LQR (Linear Quadratic Regulator). Then considering the unknown wind disturbance, a robust term is designed to replace the unknown wind disturbance, and a robust optimal control law is obtained. Global asymptotic stability of the closed-loop system is proved by Lyapunov stability theory. Simulations show that the proposed control law can achieve precise 3D UAV trajectory tracking with wind disturbance attenuation, and has good tracking performance.