Robotics researchers often turn their eyes to nature for inspiration. An international team of scientists looked to the water strider for their latest creation. Scientists from Harvard and Seoul National University, Korea teamed up to design a robotic insect that can jump off of water’s surface.
Anyone who spends time near the water has seen plenty of insects skimming along the surface. But, the team of scientists wanted to replicate the strider’s most difficult maneuver. Water jumping.
Kyu Jin Cho, the study’s co-senior author, explains the mechanics behind a water strider’s jump.
“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,” says Jin Cho. “The water strider is capable of doing all these things flawlessly.”
It took the team several attempts to understand how the water strider jumps. The water strider doesn’t push off as quickly as possible. Instead, it uses a rotational leg movement to help push off the water’s surface. The key is keeping leg contact with the water for as long as possible.
“Using its legs to push down on water, the natural water strider exerts the maximum amount of force just below the threshold that would break the water’s surface,” said the study’s co-first author Je-Sung Koh, Ph.D.
The first part of the video below illustrates how it works perfectly.
Once the team figured out the movement needed, they created a tiny robot that could exert up to 16 times its weight without breaking the water’s surface. Their robot design was inspired by the way a flea jumps and uses a “torque reversal catapult mechanism.”
The robot weighs just 68 milligrams or 0.002 ounces.
“The resulting robotic insects can achieve the same momentum and height that could be generated during a rapid jump on firm ground – but instead can do so on water – by spreading out the jumping thrust over a longer amount of time and in sustaining prolonged contact with the water’s surface,” said Robert Wood, a co-author of the study.
The study, published today in the journal Science, is all about better understanding the mechanics behind the water strider’s jump and recreating it in a robot. Will it see uses anytime soon? I doubt it. But, understanding and recreating the water strider’s jump could open the door to unique water-traversing robots.
One of robotics’ main focuses is to assist first responders. Imagine a robot that could move around during a flood.