Vision-based Ground Moving Target Tracking Using Rotor-wing UAV

Rotor-wing Unmanned Aerial Vehicles(UAVs) have the capabilities of verticaltake-off and landing, flying at a low speed, and great maneuverability, which are greatadvantages compared with fixed-wing UAVs. Therefore, rotor-wing UAVs are widelyapplied in the fields of military reconnaissance, real-time surveillance, search andrescue, and geological prospecting. As a result, the technology of vision-based targettracking using UAVs is becoming a hotspot of current research.In this article, the paper studied the problem of vision-based moving target trackingof UAV, using a small unmanned helicopter as a platform, which is equipped withgimbal and camera. The problem of vision-based moving target tracking of UAV meansthe pointing stabilization of the gimbal and the target tracking of the UAV. On thepremise of the flight control system and gimbal control system, the paper did theproblem description of the problem of gimbal and the UAV separately, and obtained therequirements of the target tracking controller. After the motion states estimation of thetarget using Kalman Filter, the paper designed the target tracking controller for thegimbal and the UAV separately. The specific implementation is as follows:Firstly, the paper did the problem description of the target tracking issue usingsmall unmanned helicopter. By the analysis of the relative motion between the UAV andthe target, the paper induced the nonlinear model of relative kinematic and the thedynamic tracking error of UAV. Then, via analyzing the tracking problem of gimbal, thepaper induced the model of gimbal control loop and the requirements of the targettracking controller.Then, the motion state of the moving target is estimated using vision measurementand Kalman Filter. The paper adopted a method based on the position of staticcharacters to compute the coordinates of target in inertial frame, after that, the KalmanFilter is introduced to estimate the target’s motion state.Finally, this paper designed the target tracking controller. By the analysis of modelof gimbal control loop, the paper designed the controller using PID method to keep thegimbal pointing at the target stably. Then the paper used Lyapunov’s second method todesign the nonlinear controller of the UAV, at last numerical simulation and analysisverifies the feasibility and the control effect of the controller.