2019 Volume 12 Issue 2 Pages 47-55
This paper presents a stereo-vision-based approach for sea-bottom docking of autonomous underwater vehicles (AUVs) for battery recharging. According to the intended application, a unidirectional docking station was designed in which the AUV has to dock from a specific direction. Real-time relative pose (position and orientation) estimation was implemented utilizing three-dimensional model-based matching to the actual target and a real-time multi-step genetic algorithm. Using the proposed approach, we conducted the experiments in which an AUV docked to a simulated underwater battery recharging station in the sea near Wakayama City, Japan. The experimental results confirmed the functionality and potential of the proposed approach for sea-bottom docking of AUVs. Although similar sea trials were reported previously, detailed discussions and performance analyses were not presented, especially regarding the relations among pose estimation, output control voltage, and photographic records. The analyses confirmed that the successful docking was realized and that the method has tolerance against turbulence applied to a remotely operated vehicle near the docking station.