Lyapunov-based trajectory tracking controller for a fixed-wing unmanned aerial vehicle in the presence of wind

This paper addresses the directional control problem of autonomous air vehicles in order to obtain trajectory tracking capabilities when flying in other than calm conditions. The control strategy is designed in the framework of the Lyapunov theory, and adaptive techniques are employed for online wind identification. An application of light fixed-wing unmanned aerial vehicles that consists in tracking straight-line paths between geo-referenced waypoints is first formulated, and the dynamic of the cross track error with respect to such trajectory is further obtained from the lateral airplane equations of motion. The dynamic order of the closed-loop adaptive system is guaranteed to be minimal by choosing the proper variables so that the tuning functions method could be applied. Several simulations taking into account unknown wind have been performed to analyze the behavior and the robustness of the control scheme. Copyright (c) 2014 John Wiley & Sons, Ltd.