Researchers develop leaf-like soft robot capable of maneuvering underwater

By Park Sae-jin Posted : April 22, 2021, 10:46 Updated : April 22, 2021, 10:46

[Courtesy of Seoul National University]

SEOUL -- A university research team has developed a sheet-shaped soft robot that can maneuver underwater using a motion similar to a leaf freefalling through the air. The robot has the potential to play a vital role in removing leaked oil in lakes and oceans. Researchers were inspired by the movement of a leaf that flutters due to air resistance when it freefalls.

A soft robot is a machine made of highly compliant materials. Such robots are mainly created using flexible polymer materials to mimic the movements of animal body parts like the movement of octopus tentacles and the body of a snake.

Seoul National University (SNU) said in a statement on April 22 that researchers from its mechanical engineering lab led by Professor Cho Kyu-jin developed a robot made of a paper-thin composite of flexible materials that can move itself to the desired position underwater through fluttering motions.

"This research has realized the idea of creating thin soft robots that can maneuver underwater in a totally new way, similar to a leaf," Cho was quoted as saying. He said the technology would open the way for the development of new types of ocean pollution removal robots.


[Courtesy of Seoul National University]

The robot is made of three parts -- a muscle-like liquid-filled elastomer, a heating circuit, and a base sheet. When heat is generated using the hexagonal-shaped soft heating circuit made of very thin stainless steel wires, a vapor pocket is created inside the liquid-filled elastomer to allow the robot's operator to control the density distribution inside the muscle-like device.

A minimal amount of momentum is generated by the density distribution of the elastomer to reorient the principal axis of the fluttering movement. Depending on the position of the principal axis, the soft robot can change its course while propelling itself underwater to reach its destination.

Researchers tested the robot attached with an absorbent pad in a simulated ocean oil spill situation and found that additional upgrades are needed for the leaf-like robot to become fully operational. The soft robot can be created in various sizes from millimeters to several meters in diameter.
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