Experimental research on movability characteristic of crawler driven ROV

In order to reduce a tension on a cable, a deep sea ROV is designed to minimize the weight. However, such a light weight will influence on the movability of crawlers. As an initial investigation experiments were conducted in a water tank using a vehicle of ROV "ABISMO" changing the weight, the buoyancy, the center of gravity and the center of buoyancy. It was observed that the ROV ran unstably in some cases in spite of the fact that the ROV could run stably on land. Especially when the weight in water of was less, the stability of the ROV got worse. It seemed that the ROV could not run on the sea floor in such cases. On the other hand, the ROV ran stably when the ROV had an adequate weight in water and adequate center of gravity as well as center of buoyancy. This paper describes the experiment results of motion of the ROV running in water by means of crawler system. This paper also describes a fundamental theoretical investigation for ROV running in water. A discrimination chart of stable running is presented for the center of gravity and the center of buoyancy. The discrimination line is obtained with the weight and the buoyancy of ROV, the water residence, the point of its application and the dimension of crawlers.