Image-Based Visual Servo Tracking Control of a Ground Moving Target for a Fixed-Wing Unmanned Aerial Vehicle

This paper proposes a new control method for the ground moving target tracking problem by a fixed-wing unmanned aerial vehicle (UAV) with a monocular pan-tilt camera. By utilizing the image-based visual servoing, the control law can be directly designed in the image plane, thereby avoiding errors caused by the 3D position calculation. Based on that, we design a control framework to integrate the control of the UAV and the pan-tilt, which enables the UAV to track the target while maintaining the feature point near the image center. Furthermore, considering that the low-cost pan-tilt camera we use has restricted characteristics, we present a deterministic finite automata model to transit the states of tracking when the pan-tilt attitude reaches saturation, thereby improving the tracking ability of the UAV for the moving target. The stability proof of the controller is given, and extensive experiments of hardware-in-the-loop (HIL) simulation and real flights are provided. The results show that the proposed method can achieve continuous robust tracking of the ground moving target.