A UAV for bridge inspection: Visual servoing control law with orientation limits

This paper describes the dynamics of an unmanned aerial vehicle (UAV) for monitoring of structures and maintenance of bridges. It presents a novel control law based on computer vision for quasi-stationary flights above a planar target. The first part of the UAV's mission is the navigation from an initial position to a final position in an unknown 3D environment. The new control law uses the homography matrix computed from the information obtained from the vision system. The control scheme will be derived with backstepping techniques. In order to keep the camera's field of view, the control law uses saturation functions for bounding the UAV orientation and limiting it to very small values. (C) 2007 Elsevier B.V. All rights reserved.