Collision Free Curved Path Following for Small Fixed-Wing UAVs

Curved path following is an essential capability for small fixed-wing unmanned aerial vehicles (UAVs), while faced with many difficulties because of the varying curvature of the reference path and nonlinear constrained kinematics of the UAV. Besides, the dynamic flight environment requires extra ability of the UAV for real-time obstacle avoidance, especially in complex airspace such as mountainous and urban area. Therefore, this paper studies the problem of curved path following with obstacle avoidance for small fixed-wing UAVs. A predictive controller guiding the UAV to minimize the distance between the virtual target point and the UAV position projected on the reference path and to avoid collision with obstacles, is developed with specially designed objective function. The dynamics of the virtual target point is designed using the Lyapunov method, which ensures the tracking stability. Simulation results verify the superiority of the proposed controller compared with several other classical path following algorithms and the obstacle avoidance effectiveness.