Inspection of Moving Structures by UAVs Using a Robust Approach Cone Strategy

In this paper, we consider the problem of inspecting a moving structure, which could be a train or a convoy, using a UAV. The moving structure is assumed to have gaps on its side to allow the UAV to enter or fly through it. Unlike earlier work in this area, since the structure is moving, the gap also moves along with it. The problem then reduces to one of a UAV trying to enter a moving window. We use the relative velocity framework to define a safe approach cone for the UAV so that its velocity vector, if directed inside this cone, will allow the UAV to pass through the window. We show that several parameters, such as the speeds of the window and the UAV, play an important part in deciding the angular span of the safe approach cone and thus have a bearing on the robustness of the guidance strategy. We establish a few theoretical results and illustrate them via simulations.