Image-based tracking control of VTOL unmanned aerial vehicles

This paper addresses the image-based control problem of vertical take-off and landing (VTOL) unmanned aerial vehicles (UAVs). Specifically, we propose a control scheme allowing the aircraft to track a moving target captured by an onboard camera where the orientation and angular velocity of the vehicle are assumed available for feedback. The proposed approach relies on appropriate image features, defined based on perspective image moments along with a useful projection, and the design of a bounded adaptive translational controller without linear velocity measurements in the presence of external disturbances. Estimates of the target's acceleration and the disturbances as well as some auxiliary variables are used to simplify the control design and guarantee the stability of the overall closed loop system. Simulation examples are provided to show the effectiveness of the proposed theoretical results.