UAV Path Planning for Complete Structural Inspection using Mixed Viewpoint Generation

A sensor-equipped Unmanned Aerial Vehicle (UAV) can be used to gather surface information of a structure, performing an autonomous inspection. It can significantly improve the efficiency of the visual inspection tasks and reduce the operating cost and the human risks involved in the tasks. A complete inspection coverage path generating method comprising two sets of viewpoints is presented in this research. The first set of viewpoints, revolving viewpoints, is generated based on the geometry of the inspection target and revolving around the target. The second set of viewpoints, gap-filling viewpoints, is generated to compensate for the insufficiency of the revolving viewpoints, filling all the unseen surface patches and guaranteeing full coverage. The system's scalability was proven by the planning outcomes for two different structures on different scales, which met both requirements of close-up inspection and photogrammetry.