A new soft bot mimics octopuses and inchworms to climb walls

PHOENIX — Soft robots really get around. Some jump, others swim or crawl on the ground (SN Online: 12/13/16). Now, one can even scale walls.

Inspired by an octopus’s suckers, researchers have constructed an inchwormlike robot that uses a pair of suction cups to scoot around vertical surfaces. The bot can clamber across rough and smooth terrain, aboveground and underwater, carrying up to five times its own weight.

This kind of free-climbing machine, described April 3 at the Materials Research Society spring meeting, could one day help conduct surveillance or inspect buildings and bridges.

Some rigid metal bots are designed to climb walls, too. But those machines are clunkier, more expensive and liable to break if they fall. Soft robots are relatively cheap to make and are lightweight and resilient, so there’s less risk involved with them losing their grip.

The new robot is made of silicone rubber — a choice material for building soft, flexible, cephalopod-inspired machinery (SN: 11/11/17, p. 5). To move, the robot detaches one suction cup from the wall, straightens its spine and plants the sucker back down. It then peels up its other suction cup, arches its spine to pull the sucker forward, plants it and repeats.

Researchers control the bending and stretching of the robot’s spine, and the suction cup attaching and detaching, by injecting air into and sucking air out of cavities embedded in the silicone. Tubes connected to the prototype bot supply this air. But the scientists want to devise a way to untether the artificial inchworm, said study coauthor Yichao Tang, an engineer at Temple University in Philadelphia.