Mamoru Nagai

Development of a curving excavation method for a lunar-subsurface explorer using a peristaltic crawling mechanism

We have developed an excavation robot for lunar-subsurface exploration. This robot moves using a mechanism based on the peristaltic crawling of earthworms, which can move stably. In our previous study, we demonstrated that the robot can excavate down to 938 mm using this technique. However, it can only excavate in a straight configuration. If it can excavate while curving, its exploration range would expand. Therefore, in this paper, we develop a curving-excavation method for this robot. Firstly, this method is proposed and developed. Secondly, we design the propulsion units necessary to realize this method. Finally, we conduct experiments to confirm curving motion using a robot equipped with the designed unit and evaluate the performance of this method.

Development of a Hydraulic Artificial Muscle for a Deep-Seafloor Excavation Robot with a Peristaltic Crawling Mechanism

In recent years, observations and explorations of the deep seafloor have been actively pursued. One goal of such explorations is to obtain the samples of seafloor mud and its inclusions. Mud that contains minerals and submarine microorganisms has great potential for studies in biology, geology, and marine science. To contribute to these efforts, we propose a robot using peristaltic crawling to excavate deep seafloor. The robot consists of three parts: excavation, propulsion, and extraction units. The propulsion actuator of the proposed robot must be able to function under water at high pressures. As the first stage in the development, we developed a subunit using an oil hydraulic artificial muscle intended for use in deep sea, and conducted a performance experiment under water pressure. Our results confirmed that the artificial muscle can be used in water pressures of up to 5 MPa.

Development of seabed excavation robot with peristaltic crawling

Sub-seafloor explorations are important for biological and geological research. Sampling mud is one of the major sub-seafloor exploration procedures. The mud-including mineral resources and marine sediments are potentially valuable resources for future studies. Therefore, we propose a peristaltic-crawling-based sub-seafloor excavation robot for deep sea exploration. This robot consists of three units (propulsion, excavation and extraction units), enabling it to move freely through mud. The excavation and propulsion units are fitted with an earth auger and artificial muscles, respectively. In this paper, we verify the propulsion actuator as the first stage of robot development. First, we evaluate the performance of an oil hydraulic artificial muscle under water pressure. Next, we develop an excavation robot by incorporating a pneumatic artificial muscle into a robot and then experimentally evaluate propulsion and excavation of the robot. We confirmed that the artificial muscle appropriately performs as an actuator for the excavation robot.