Experiment on Underwater Docking of an Autonomous Underwater Vehicle `ISiMI' using Optical Terminal Guidance

An AUV (Autonomous Underwater Vehicle) being able to dock without surfacing to a launcher or an underwater station can give us long-time duration. It is important for the AUV to be guided to the dock safely. This paper introduces a test bed platform AUV named ISiMI and her optical terminal guidance system. ISiMI uses the optical terminal guidance system for underwater docking. The guidance system consists of a hardware part and a software part. One CCD camera and a frame grabber constitute the hardware part. An image process and a final approach algorithm based on visual servo control are the software part. A dock center which is a final approach target position of ISiMI is estimated by the image process and a reference yaw and pitch are generated by the final approach algorithm. We developed, also, an auxiliary controller to reinforce the final approach algorithm. This additional controller is necessary because there is an area where ISiMI cannot see the target lights near the dock. This makes the performance of docking better. Underwater docking experiments were conducted and the results are included in this paper.