A joint research team composed of professors and graduate students from the Department of Mechanical and Aerospace Engineering and Department of Biological Sciences at Seoul University, in collaboration with the School of Engineering and Applied Sciences at Harvard University, were successfully able to determine the principle behind the jumping movement of a pond skater on water, and implement it on a ultralight robot.

When a pond skater leaps from the surface of water, instead of simply pushing the surface down, it widen its legs and rotate them inside towards the center first. This enables the legs to maximize its time pressing downward on the surface, extending the length of acceleration. Also, it controls the force of its legs pushing down on the surface just short of breaking surface tension. This way, it minimizes the risk of the legs falling straight through the water.

From these findings, the research team was able to develop a robot that effectively uses surface tension to leap from the surface of water. Using a torque reversal catapult mechanism, they were able to mimic the leg rotation process while controlling the force of the thrust. As a result, the 68 mg ultralight robot was able to jump as high on water as if it was on solid ground

In the near future, miniature robots are envisioned to enter disaster zones and scatter to collect information and perform reconnaissance. The ability to jump from liquid surfaces may prove invaluable. This research was posted on the July online version of Science.