Experiments of flipper type crawler system at sea to verify running performance on sandy or irregular steep terrain seafloor

A crawler system as a mobility function on the seafloor has the possibility to expand the activity of research and development on the irregular terrain and the sand seafloor. Investigation of equilibrium running dynamic and motion such as a slip of the crawler type ROV is of importance to realize the activity there because characteristic parameters in water such as buoyancy and hydrodynamic forces will considerably affect and lower the mobility performance. So, the analysis model to express dynamic motion of the crawler type ROV is established. And experiments to evaluate the slip characteristic were conducted in a water tank and on the sand seafloor at sea. In addition, to improve the mobility, a flipper-type crawler system was developed. And the preliminary experiment revealed it had the performance advantage. Then three sizes of the flipper type crawler ROVs were developed and experiments of running on the seafloor and on the rock reef which is an irregular steep terrain seafloor at sea were conducted. This paper describes the dynamic motion of crawler system such as slip when running on a sand seafloor and also results of the running experiments on the sand and on the rock reef.