ResearchResearch at Tokai

Research ExcellenceThe Development and High-precision Control of Underwater Robots with Work Arms

His research on underwater robots began with an advising professor when he was a student

Associate Professor Norimitsu Sakagami's specialty is robotics. He is developing underwater robots that are small, lightweight and can work skillfully.

He says that in his student days, when he belonged to a laboratory, there was not yet anyone there doing research on underwater robots. When, then, did he begin researching underwater robots? Sakagami told us his slightly unusual story:

"The lab I joined specialized in developing land robots. The advising professor was full of human warmth and charm, and I had decided to join his lab the moment I took his class as a second year student. It was around the time when the campus of the Ritsumeikan University College of Science and Engineering that I belonged to moved to Shiga Prefecture, and the impetus for me getting involved with this research was when the professor said, 'Since we have Lake Biwa right here, let's research underwater robots.' It was the first underwater robot for the professor himself. The staff and students together started the research from square one."

The research that was done by the teaching staff and students working closely together continued to develop and Sakagami is still engaged in leading-edge joint research on underwater robots with his former advisor.

Divers are the competition - working to create an underwater robot with the size and skill of a person

Many underwater work robots are large, and usually they are operated by experts. In contrast, Sakagami is aiming to create small, light, underwater robots anyone can operate.

“For example, during the observation of fish, if a fish that interests a researcher appears, he tells the operator to 'follow that fish,' and then the operator starts controlling the robot after receiving that instruction. But by then, the fish is gone. If the researcher could operate the robot himself, the efficiency of his observation would improve markedly. When you think about the convenience of transporting a robot, it is essential for it to be small and light as well."

Also, divers are responsible for much minute work underwater, and there is always danger involved. What we are developing to avoid that risk is an underwater robot with the size, weight and skill set of a human being.

"The competition really is diverse," Sakagami said. Research on underwater robots for a wide variety of uses is taking place at the laboratory, and one even students can operate that is put together underwater has already been developed.

His research stance is to make robots that are actually useful in the field

Sakagami is currently doing research jointly with researchers from various fields that relates to the development of robots that match their respective uses. For research on the environment of Lake Biwa he is carrying out with biology researchers, they are using a robot to collect sludge from the bottom of the lake.

In a survey of historical ruins on the ocean floor near Ishigaki Island he is carrying out with archaeology researchers, they are using robots to photograph conditions on the ocean floor while pinning down the locations of ruins using GPS. "My research stance is to make robots that are actually useful in the field," Sakagami emphasized.

Finally, Sakagami told us about the future development of his research.

"The School of Marine Science and Technology is a comprehensive department whose field is the sea, and it has researchers from a wide variety of realms. I would like to partner with such researchers and carry out research only possible at Tokai University. Also, Suruga Bay, which has a depth of over 1,000 meters, is near the department. I would like to work to develop robots that can work in the depths of the sea as well. In the future, just as I am currently conducting research with my former advising professor, I would be a very happy, lucky researcher if I could do joint research with students I am giving guidance to now after they become researchers."

1 — Mitsurugi
Underwater robot for bottom sludge collection. Weighing some 34 kilograms, it has a sludge collecting pipe. It is carrying out sludge collection experiments in Lake Biwa. The team is aiming for automatic sludge collection using GPS and directional indicators. Joint research by Ritsumeikan University and Oyo Corporation.
2 — Koko
Human-sized underwater robot. Weighing 63 kilograms, it has human-sized arms. It is carrying out experiments in picking up tires and collecting sludge at the bottom of Lake Biwa. The team is also developing an easy control system. Joint research by Ritsumeikan University and Dainippon Screen.
3 — Arutemi
Underwater robotic gripper. Weighing some 30 kilograms, it has a large gripper and achieves skillful operation underwater. The team aims to develop a control system to permit easy control by amateurs as well as professionals. Joint research by Ritsumeikan University and Oyo Corporation.
4 — Robots and archaeologists
This research is being carried out by the School of Marine Science and Technology and the Research Institute for Humanity and Nature's Area Capability Project. It is a joint research project with Associate Professor Rintaro Ono of the School of Marine Science and Technology's Department of Maritime Civilizations. Survey of historical ruins on the ocean floor off Yarabuzaki, Ishigaki. Four-claw iron anchor at left of photo and archaeologist (diver) at center.

Photography: Yuji Yamamoto (Underwater cultural heritage photographer)

Associate Professor Norimitsu Sakagami

Born in 1974 in Shiga Prefecture. Completed a doctoral program in mechanical systems in the Graduate School of Science and Engineering, Ritsumeikan University, and holds a doctorate in engineering. After serving as an assistant in the Ritsumeikan University College of Science and Engineering, in 2004 he became a junior associate professor in the Department of Marine Design and Engineering, the School of Marine Science and Technology, Tokai University. In 2008, he became an associate professor in the Department of Naval Architecture and Ocean Engineering (currently the Ocean Engineering course, Department of Navigation and Ocean Engineering).

Visiting researcher at the Ritsumeikan University Robotics Research Center (April 2008 to present), visiting researcher at the National Institutes for the Humanities (June 2011 to present)