Seoul National University College of Engineering Professor Cho Gyo-jin's joint research team, inspired by leaves
Paper-thin underwater soft robot technology concept demonstrated


Seoul National University College of Engineering announced on the 22nd that a joint research team led by Professor Kyu-Jin Cho of the Department of Mechanical Engineering has developed paper-thin underwater soft robot technology.

The research team succeeded in creating a new underwater behavioral pattern with a paper-thin structure by developing a density distribution control technology in the form of thin skin. This research, supported by the National Research Foundation of Korea’s Leading Research Center Program and the Basic Research Program’s Next Generation Academic Training Program, was published in the April 21 issue of 'Science Robotics,' a prestigious journal in the field of robotics.

Light and thin objects, such as leaves or paper, create colorful movements without special propulsion due to air resistance. The research team identified that this movement depends heavily on the density distribution of the object, and that this effect is further maximized in underwater environments. Furthermore, they succeeded in actively controlling the density distribution of the entire system by patterning a flexible composite material, whose density changes significantly in response to heat, into a skin-thin layer.

Density distribution control technology enables arbitrary, paper-thin structures to move to desired locations with fluttering underwater behavior resembling leaves, without extreme body deformation or propeller-like thrusters. It can be applied across a wide range of sizes, from millimeter-scale dimensions to large areas exceeding several meters, and holds the potential to integrate various functions required for exploration and marine environmental maintenance.

To demonstrate this feasibility, the research team showcased a concept in a small water tank where an oil-absorbing sheet autonomously swims to reach an oil spill site and removes contaminants. Although it is not yet equipped with batteries or electronic circuits, and further research is needed regarding movement control in flowing water, it is expected that further development of this current conceptual study will demonstrate new possibilities for underwater soft robots.