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Title Close visual bridge inspection using a UAV with a passive rotating spherical shell
Posted by Carl John Salaan
Authors Carl JohnO. Salaan, Yoshito Okada, Shoma Mizutani, Takuma Ishii, Keishi Koura, Kazunori Ohno, and Satoshi Tadokoro
Publication date 2018/2
Journal Journal of Field Robotics
Publisher Wiley
Abstract Today, robots are expected to be used for the inspection of infrastructures such as bridges. One important task in bridge inspection is to acquire clear images of its various parts for further damage evaluation. However, this task has not yet been completely realized because of the complexity of bridge structures. For this situation, a UAV with a passive rotating spherical shell (PRSS) that can easily maneuver while protecting itself is introduced. In this paper, we explain the development of the PRSS unmanned aerial vehicle (UAV) based on the design strategy.We then analyze its performance through simulated bridge inspection. Finally, we discuss the results of actual bridge experiments. The spherical shell has a size (D =0.95 m) and structure (fullerene) that is well-suited for bridge inspection applications. It can also handle an impact equivalent to 2 m/s, which is more than the UAV's maximum flight speed. Test flight experiment also validated the characteristic of PRSS that shows a stable flight during disturbances. The image test also shows that the visual system can provide a full overhead view of the bridge. Likewise, it can detect a 0.1-mm wide line that replicates the damage (e.g., a crack) from a position 0.5maway and while the cameramoves at 0.3 m/s. These characteristics have yielded a system that can acquire inspection images from critical parts of the bridge. An evaluation by third parties confirmed the effectiveness of the system. Further, the system satisfies the mandatory requirements of the Next Generation Robots for Social Infrastructure (NGRSI) program.
DOI 10.1002/rob.21781