H. Montes et al. (eds.), CLAWAR 2018: 21st International Conference on Climbing and Walking Robots and the Support Technologies for Mobile Machines, Robotics Transforming the Future © ELSEVIER PROPOSAL OF PROPULSION UNIT BASED ON EARTHWORM SETAE FOR UNDERWATER EXCAVATION ROBOT NAOAKI TADAMI, KEITA ISAKA, TOYOHARU NAKATAKE, AMI FUJIWARA YASUYUKI YAMADA, TARO NAKAMURA Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo, 112-8551, Japan MAKOTO SUGESAWA, HIROSHI YOSHIDA Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa, Japan In this paper, we developed a propulsion unit with bristles imitating the setae of earthworm. This propulsion unit is installed in SEAVO: sub-seafloor excavation robot. To realize underwater excavation by SEAVO, it is necessary to move the soft and fluid sedimentary layer of seafloor surface. As a solution, we focused on the setae of earthworm which live in mud and soft soil. Then, we developed the propulsion unit with bristles imitating the earthworm's setae and measured the performance of the bristles- attached propulsion unit. Comparing the measurement result of the bristles-attached propulsion unit with the previous propulsion unit, we confirmed the usefulness of the bristles-attached propulsion unit. Keywords: Excavation robot, earth auger, Seabed exploration 1. Introduction The ocean occupies about 70 % of the earth's surface area. Recent studies have confirmed the existence of various mineral resources on this vast seabed. 1 To elucidate the reserves and generation process of these resources, it is necessary to explore the detail of seabed in a wide area. One of the seabed exploration has sampling. 2 In the current exploration, descending equipment such as drill string from the research vessel to collect soil at the seabed. 3 However, as the water depth gets deeper, exploration equipment and vessels become larger the size and increase the operation cost. In addition, since the area of these exploration is limited to one spot, it is not suitable for investigation of wide area. This problem can be improved by the cost reduction and the high efficiency exploration. Therefore, we will develop the robot that explore freely under seabed. Then, we realize low-cost and highly effective exploration by multiple robots.