Nowadays, the necessity of underwater operation is increasing while the ocean development is progressing actively. Owing to resources in the ocean floor and military purposes, the demand of underwater operation is occurring in many fields. AUV is one of the most representative equipments for deep sea probes because of its autonomous characteristics, and AUV must have docking operation in order to be completely autonomous. Docking is an operation that AUV is fixed with the launcher exactly when it is close to the launcher and very difficult since the position of the launcher can be changed easily by ocean current and waves.
In this study, development of AUV for docking test is performed. Underwater CCD camera which is used for sensing image of beacons on dock is placed at the end of nose-cone. And batteries, main-controller, vision-board, and various sensors are in the mid-section of AUV. At the tail-section which is oil-filled, BLDC motor and linear step motors for driving propeller and direction fins. Driving test of AUV model in water tank is performed.
To know the relative position and pose of dock to CCD camera of AUV, algorithm using the fact that the length of diameter of circle in 3-D and the length of major axis of its 2-D-projected ellipse are the same is suggested. At first, Arrangement of beacons on dock is presented, and then, correspondence problem between feature points of image and real beacons is solved. From characteristic components of ellipse fitted by 5 feature points, relative position and pose of dock is obtained. Experiments and simulations for vision algorithm are performed.
