Scientists create an insect-like robot that can walk on water

By observing water striders using high-speed cameras, the scientists noticed that the insects do not simply push down on the water, but gradually accelerate their legs so as not to break the surface tension.

Researchers in Korea have developed a robot that can mimic water striders, with the bio-inspired long-legged bot leaping across water thanks to a very clever design.

“This robotic technology could probably be used for building [a] large number of robots that can float, and jump on water for surveillance missions”.

Robert Wood, another co-author, added: “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”. In order to create the mechanisms for the robot to successfully launch itself from the water’s surface, the researchers from Seoul National University and Harvard University analyzed how water striders (Gerridae) were able to jump on water.

The researchers envisage an environmental application for their robotic water strider – monitoring pollution in waterways.

The water strider, whose legs have slightly curved tips, employs a rotational leg movement to aid its takeoff from the water’s surface.

The prototype robot weighs just two-thousandths of an ounce (68 milligrams) and has a 3/4-inch (2- centimeter) long body.

The Verge wrote that the goal of the study was to observe and explore aquatic mobility in a tiny robot. For the robotic insect to jump off the water, it uses a lightweight catapult mechanism coupled with limited thrust to propel itself off the water without breaking the water’s surface.

The authors theorized that the maximum force of the striders’ legs is always just below the maximum force that water surface tension can withstand.

“[These imaging experiments] revealed that the insect rises upward while pushing the water surface downward and closing four of its legs inward”. If the surface remains unbroken, it can tolerate 16 times the body weight of the artificial bug.