Washington (AFP)
A team from the University of Southern California has developed an 88 milligram robot that moves, climbs and carries loads using artificial muscles, after solving a problem that has long held engineers in check: the source of energy on such small robots.
They named their robot "RoBeetle", or beetle robot. It is only 15 millimeters in length, which makes the robotic beetle "one of the lightest and smallest autonomous robots ever created," its inventor, Xiufeng Yang, told AFP.
"We wanted to create a robot whose weight and size would be comparable to those of real insects", adds the researcher, first author of the article describing the invention Wednesday in the journal Science Robotics.
Most robots need electric motors to move forward, and therefore batteries. But the smallest existing batteries weigh between 10 and 20 times more than the 50 milligram beetle the team took as a reference animal.
Xiufeng Yang's team therefore developed an artificial muscular system based on a liquid fuel, in this case methanol, capable of providing ten times more energy than a battery of identical mass.
Muscles are made of an alloy of nickel and titanium wires (Nitinol) which contract lengthwise when heated (unlike most metals, which lengthen). The heat was caused by the contact between the methanol vapor emanating from the tank and a catalyst sheathing the wires (a platinum powder).
The steam heated the wires, the "muscles" contracted, then microvalves automatically stopped the combustion, and the muscles stretched again, triggering the reopening of the valves and a new cycle of contraction-extension of the muscles, until exhaustion. of the tank.
The system was able to move the beetle's front legs forward on flat surfaces, like glass, or rough, like the top of a mattress, for up to two hours in a row - with up to 2.6 times its weight on the back.
By comparison, "the smallest four-legged battery-powered robot weighs one gram and operates for about 12 minutes," Xiufeng Yang said.
What can these mini-robots be used for? Infrastructure inspections, rescue missions after a natural disaster, even artificial pollinations or environmental monitoring programs.
But for the time being, the lack of on-board electronics, and the fact that it only knows how to move forward, limit its usefulness, point out roboticists Ryan Truby and Shuguang Li, of MIT and Harvard respectively, in a commentary published by the same journal.
© 2020 AFP