[VIDEO] Robot and Insect: Smooth Moves on Water's Surface Tension

It's easy to admire the graceful skimming of a water strider insect on a pond surface. Researchers from Seoul National University and Harvard University have taken that admiration--for certain insects' ability to leverage water's surface tension while moving on it and launching off it--and created a robot that can jump off water's surface.

The scientists recently reported on their robotic insect in the journal Science.

"Water's surface needs to be pressed at the right speed for an adequate amount of time, up to a certain depth, in order to achieve jumping," said the study's co-senior author Kyu Jin Cho of SNU, in a release. "The water strider is capable of doing all these things flawlessly."

In their study, they learned that the water strider uses a rotational leg movement to improve its launch from the water's surface. The researchers collected water striders and make videos of their movements in order to learn the mechanics involved in skimming and moving away from the water, as the release noted.

They learned that if too much force is applied on the water, the limbs will puncture the surface and ruin the attempt at lift-off. Eventually, they realized a robot that could maintain leg contact on the water for as long as possible while beginning to jump was able to achieve the full movement, said the release.

So, the robotic insect is able to exert up to 16 times its body weight on the water surface without knocking through it, and can do so without involved controls. As they note, many organisms can achieve extreme styles of locomotion without having complex cognitive skills, according to the release.

This is because of the creatures' physical intelligence, notes Cho in the release.

In part, the robotic insect was also inspired by a flea's style of jumping, and was first reported in 2013 at the International Conference on Intelligent Robots and Systems, the release said.

The robotics scientists employed a lightweight catapult mechanism that involves a momentum burst and limited thrust that sends the robot off the water smoothly. They also included folded structures within the robot that assemble a bit like 3D pop-up books, the release confirmed.

To see a YouTube video of the robotic insect jumping, click here. 

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