Discover robots that walk on water thanks to the secret of insects

Rhagovelia, a semi-aquatic insect, have fan-shaped appendages at the tips of their mid-legs that open and close passively depending on the movement of the water below. This is why they glide effortlessly across the surface of the water.

Biologist Victor Ortega-Jimenez of the University of California, Berkeley, is fascinated by how these tiny insects can accelerate, make quick turns and other maneuvers, almost as if they were flying on the surface of a liquid.

Rhagobot was inspired by structures found on the legs of the Rhagovelia water beetle (Source: Arstechnica)

“The propeller of Rhagovelia serves as an inspiring template for developing self-morphing artificial propellers, providing insights into their shape and biological function,” he said in a recent study published in the journal Science.

“Such configurations remain largely unexplored in semi-aquatic robots,” says biologist Victor Ortega-Jimenez.

It took Ortega-Jimenez five years to figure out how the insect moves. While it was thought that Rhagovelia’s fan-legs transformed through muscle power, he discovered that the appendages automatically adjust to the surface tension and elastic forces beneath them, opening and closing passively at ten times the speed of the blink of an eye. They expand instantly upon contact with water and change shape depending on the current.

Rhagobot is Ortega-Jimenez's version of this high-tech insect. After carefully studying the structure and function of Rhagovelia's legs and propellers, he and his team created artificial versions that are also designed to transform when exposed to water.

Motion image of Rhagobot on water

They are attached to the Rhagobot's mid-legs. Like their inspiration, the blades extend instantly when submerged in water and close when they are protruding. No additional power source is required as the blade's shape is determined by the movement and speed of the water.

The team wanted to see if their artificial fans would give Rhagobot an advantage. They built a replacement robot, modeled after another species of water strider that could propel itself using surface tension, and pitted it against Rhagobot.

Both are powered by the same amount of energy, but Rhagobot can travel further and make sharp turns faster than its opponent thanks to its fans.

“The thrust generated by the fan increases forward speed and allows for quick braking,” says Ortega-Jimenez.

At the same time, he added: “The fan's ability to retract also significantly reduces the energy needed for the robot to lift its legs out of the water.”

In the future, Rhagobots could traverse rough waters to become part of an environmental monitoring system, and researchers are excited about the potential for swarms of these robots to assist in search and rescue missions during storms and floods, although adding the weight of sensors and power would be a significant challenge.

It could even explore places beyond Earth. If Rhagovelia proves anything, it's that even the smallest creatures can make great strides, on water or anywhere else.

Minh Hoan

Source: https://vtcnews.vn/kham-pha-robot-di-tren-nuoc-nho-bi-mat-cua-con-trung-ar960912.html