Development of a Wall-climbing Welding Robot for Draft Mark on the Curved Surface

선수미 흘수마크 용접을 위한 벽면이동로봇 개발

The vertical displacement of a ship on the basis of the sea level is an important parameter for its stability and control. To indicate the displacement on operating conditions, "draft marks" are carved on the hull of the ship in various ways. One of the methods is welding. The position, shape and size of the marks are specified on the shipbuilding rules by classification societies to be checked by shipbuilders. In most cases, high-skilled workers do the welding along the drawing for the marks and welding bead becomes the marks. But the inaccuracies due to human errors and high labor cost increase the needs for automating the work process of the draft marks. In the preceding work, an indoor robot was developed for automatic marking system on flat surfaces and the work proved that the robot welding was more effective and accurate than manual welding. However, many parts of the hull structure constructed at the outdoor are cowed shapes, which is beyond the capability of the robot developed for the indoor works on the flat surface. The marking on the curved steel surface requiring the 25m elevations is one of the main challenges to the conventional robots. In the present paper, the robot capable of climbing vertical curved steel surfaces and performing the welding at the marked position by effectively solving the problems mentioned earlier is presented.