Those who were terrified by the "spider robots" that were after Tom Cruise's character in the sci-fi film Minority Report might get shivers down their spine upon catching sight of a new insect-inspired robot. Fortunately, these robots were designed not for surveillance but for science.
A team of scientists from Seoul National University and Harvard University closely studied how insects known as water striders use their wiry legs to launch themselves from the surface of water to create tiny robots capable of the same feat. They report in the journal Science that the bouncing bots are a useful tool for studying the properties of water – but they do acknowledge the possibility of exploiting this technology to create surveillance robots.
"A small insect-mimicking robot cannot perform complicated tasks as large robots – like humanoids – aim to do. But there are situations where you don't need an expensive large robot but need many small cheap robots carrying out simple tasks over a wide area at the same time," the study authors wrote in a statement. "Those applications include surveillance."
That application is certainly not the goal of the research, however.
"We did not have much intention to put this robot in a market for those who are looking for surveillance robots in near future," they went on to write. "Of course, we do not want the robots to be used by bad people."
The primary motivation for building these robots, according to the researchers, was simply to prove that it is possible. It doesn't take a degree in physics to understand that figuring out how to jump from water isn't easy, and water striders are among the very few organisms that can do it.
Water striders have several clever tricks for hopping off water, including their thin legs and lightweight bodies. These features, among others, help the insects take advantage of water's high surface tension.
This property, as the name suggests, refers to how much force is needed to penetrate the surface of a liquid. It's a result of the attraction between the molecules in the liquid and it's the same property that causes water to bead up when sprayed on an object.
Upon closer inspection, the researchers noticed another key to the water strider's success – it always rotates its legs inward. This also helps it exploit surface tension by allowing it to gradually increase the amount of force it imparts on the water's surface.
The researchers incorporated all of these strategies and others into the robot's design and were able to create a tiny robot that is very good at jumping off of water. They hope, above all, that this new technology will aid the studies of biologists and robotics researchers alike.
"Biologists will now have tools to better understand the nature, fluid mechanics researchers have tools to better understand the dynamic interaction between the water and an object, robotics researchers have the tools to implement this extreme locomotion of jumping on water," they wrote.
