- Research by Prof. Koh Je-sung’s group at Ajou University appears as the cover article in Science

- Findings point to applications in next-generation aquatic robots, ocean exploration, and disaster response

The Ministry of Science and ICT (Minister Bae Kyunghoon) announced that a research team led by Professor Koh Je-Sung at Ajou University, with Dr. Dongjin Kim as first author, has succeeded in developing the world’s first micro-scale robot modeled after the ripple bug (Rhagovelia)—an insect capable of agile movement on water surfaces.

Supported by the Ministry’s Basic Research Project (Young Researcher and Basic Research Laboratory projects), this achievement was published as the cover article in Science, the world’s premier academic journal, on August 22 (local time: August 21, 2:00 p.m. EDT).
*Paper Title: Ultrafast elastocapillary fans control agile maneuvering in ripple bugs and robots

Rhagovelia, a member of the water strider family, produces powerful thrust and agile movement even in rapid currents thanks to the fan-shaped structures at the tips of its legs. Until now, the exact mechanism by which these fans operate in such a short time had not been scientifically elucidated.

To identify the underlying principles of this natural phenomenon, the researchers constructed a robot with the same structural features. Unlike previous efforts relying solely on simple leg structures or muscle-based mechanisms, which were limited in replicating insect-like speed adjustment, turning, and stopping, this research successfully demonstrated complex, rapid motion on water surfaces.

Professor Koh’s team launched the project in collaboration with research groups from the University of California, Berkeley, and Georgia Institute of Technology. Together, they developed a micro-robot equipped with 21 string-like artificial hairs arranged into a fan-shaped structure, mimicking the natural design of Rhagovelia’s legs.

Experiments revealed that this structure enabled the robot to generate strong thrust and agile directional changes—just like its biological inspiration.

The team discovered that the fan at the tip of Rhagovelia’s legs deploys not through muscle power, but via elastocapillary interaction: when submerged, the fan rapidly unfolds within 0.01 seconds due to the combined effect of elasticity and water’s surface tension, and then folds back instantly upon leaving the water.

This research is the culmination of Professor Koh’s 15 years of continuous study into the water-surface locomotion of strider insects—a persistent effort that played a key role in the success of this project.

Professor Koh stated, “Elucidating the structural intelligence found in natural insects will enable future applications in fields such as environmental monitoring, rescue operations, and the development of bio-inspired robotic engineering.”

For further information, please contact the Public Relations Division (Phone: +82-44-202-4034, E-mail: msitmedia@korea.kr) of the Ministry of Science and ICT.


※ Please refer to the attached PDF.