The machine seems to be impossibly floating across the surface of water when, all of a sudden, it whips its 4 skinny legs towards its center in a single clean motion and blasts upward. Leaping with the force of 14g’s, it’s airborne faster than you may blink, easily leaping as fast and as high as it could have on land. However that is no pond-skater, Jesus lizard, or some Gerridae. It’s a mini-robot.
The world’s first robot that jumps from the surface of water using surface tension has been developed by a team of Korean roboticists. The 1 cm tall robot can jump to a height of 14 cm.
Engineers and roboticists at the Seoul Nationwide College in South Korea, led by Je-Sung Koh, have designed the first robot to imitate jumping water bugs like water striders. The robot balances on water and leaps into the air utilizing little more than the force of water’s natural surface-tension. The team stated in the journal Science, that they first needed to work out the mystery of how bugs like the ‘water strider’ manage this feat before they could construct a machine to imitate it.
Utilizing high-speed cameras, the roboticists recorded jumping water striders (Aquarius paludum) they caught in ponds and streams outside Seoul. After studying their videos in detail, the team broke down the mechanics of how the insects avoid breaking the surface tension during their powerful leap.
One key to their leap is that water striders steadily and gradually increase their jumping power. How do they do that? By wicking their curved legs inward, across the water, keeping much of their leg in touch with the tiny divots each leg creates. This permits water striders to transfer the power generated by the water’s surface tension (which is trying to make it stay flat) into their upward motion.
The new robot jumps by utilizing a simple, light clasp that snaps shut via a heat-reactant spring after being zapped by an outside pulse of heat. That clasp generates the force needed to maneuver the legs, causing the robot’s 4 curved legs, that are generously coated with a water-repellent chemical known as Ultra-Ever Dry, to tug inwards. The researchers got the robot’s legs to imitate a water strider’s by constructing them with a super-elastic nickel-titanium alloy.
This new jumping robot isn’t the first to ever stroll across the surface of water (Robostrider claims that title). The work carried out on earlier robots, combined with the team’s study of water striders in nature, helped them design their running and leaping little machine. Mainly, just like an actual water strider, the bot can stand on water because its light weight is spread broadly across its four legs, causing a force that is far lower than force of water attempting to retain a taught surface.