Water Jetting Excavation and Consideration of Earth Auger Shape to Reduce Drilling Torque for Seabed Robotic Explorer

Marine resources exist on the seabed, and sampling is useful for a detailed study of these resources. In general, a pipe-shaped sampler is used to collect marine resources for investigation. However, this is inefficient and expensive for investigating sediments, which are widely distributed, because the sampling range is limited to the pipe penetration part. Wide area exploration can be made possible by deploying multiple robots to autonomously search beneath the seabed. In a previous study, we developed a seabed robotic explorer called “SEAVO” and experimentally demonstrated the ability of SEAVO to produce curved boreholes with a turning radius of 1.67 m, and a depth of 613 mm, in the land environment. However, underwater excavation has not been successful. Reduction in the drilling torque is necessary for underwater excavation. In this paper, we propose a water jetting excavation method and consider the shape of the earth auger to reduce the drilling torque.