Even without a brain, metal-eating robots can search for food

When it comes to powering mobile robots, batteries present a problematic paradox: the more energy they contain, the more they weigh, and thus the more energy the robot needs to move. Energy harvesters, like solar panels, might work for some applications, but they don’t deliver power quickly or consistently enough for sustained travel.

Film still of a small wheeled robot traveling a path between yellow tape.
The “metal-eating” robot can follow a metal path without using a computer or needing a battery. By wiring the power-supplying units to the wheels on the opposite side, the robot autonomously navigates away from the tape and towards aluminum surfaces. (Image: Penn Engineering Today)

James Pikul, assistant professor in Penn Engineering’s Department of Mechanical Engineering and Applied Mechanics, is developing robot-powering technology that has the best of both worlds. His environmentally controlled voltage source, or ECVS, works like a battery, in that the energy is produced by repeatedly breaking and forming chemical bonds, but it escapes the weight paradox by finding those chemical bonds in the robot’s environment, like a harvester. While in contact with a metal surface, an ECVS unit catalyzes an oxidation reaction with the surrounding air, powering the robot with the freed electrons.

Pikul’s approach was inspired by how animals power themselves through foraging for chemical bonds in the form of food. And like a simple organism, these ECVS-powered robots are now capable of searching for their own food sources despite lacking a “brain.”

In a new study published as an Editor’s Choice article in Advanced Intelligent Systems, Pikul, along with lab members Min Wang and Yue Gao, demonstrate a wheeled robot that can navigate its environment without a computer. By having the left and right wheels of the robot powered by different ECVS units, they show a rudimentary form of navigation and foraging, where the robot will automatically steer toward metallic surfaces it can “eat.”

Read more at Penn Engineering Today.