Flight path optimization for UAV bridge inspection considering viewpoint importance and verification with 3D model in virtual space

Abstract

Since some studies and implementations of UAV bridge inspections to efficiently recognize structural damages are recently active, it is required to achieve not only effective cost reductions but also inspection performances of required damage recognition accuracies. In this study, a flight path optimization for the inspection of a steel plate-girder bridge was verified by the flight simulation in a 3D model of the bridge in the virtual space. Based on surveying the bridge inspection standard, damage-prone areas were identified, and the view point of interest (VPI) and the viewpoint importance levels were determined. Then, the optimal path was calculated using some optimization methods. Comparing the optimized flight paths between without and with considerations to the viewpoint importance, ant colony optimization (ACO) method showed good performances to derive the shortest path length even in the viewpoint importance was considered. Although the path length became longer when the viewpoint importance was considered, and the flight simulation results could confirm that the same angle of views to bridge members required to be visually inspected at a short distance were obtained.