A so-called ‘soft’ robot that crawls along like an earthworm – and can continue to work even after being hit with a hammer – has been developed by researchers at the Massachusetts Institute of Technology (MIT), Harvard University and Seoul National University.
It may not be what usually comes to mind when you think of a robot, but this one, it must be said, is rather unique.
Named Meshworm, it moves in a similar way to an earthworm, or a sea cucumber, or even the muscles inside our body which push food along the esophagus to our stomach – by alternately squeezing and stretching. This continuous wave of contractions is known as peristalsis.
Researchers created the “artificial muscle” using nickel and titanium, producing a soft, flexible, mesh-like tube that stretches and contracts with heat.
Perhaps the most remarkable thing about Meshworm is its ability to withstand some pretty rough treatment. Clobber most robots with a hammer and it will likely result in some sparks, puffs of smoke and a major malfunction. Clobber Meshworm and it just continues crawling along as if nothing’s happened – as demonstrated in the video below. It can also survive someone stepping on it.
Sangbae Kim, an associate professor of mechanical engineering at MIT and a member of the team working on Meshworm, said even throwing the tiny robot around won’t cause it any damage.
“Most mechanical parts are rigid and fragile at small scale, but the parts in Meshworms are all fibrous and flexible. The muscles are soft, and the body is soft,” Kim told MIT News.
Up to now, the difficult part for those involved in soft robotic development had been how to power the robot. Designs using compressed air have been examined, but needed bulky pumps. “Integrating micro air compressors into a small autonomous robot is a challenge,” Kim explained.
His team then had the idea to look at how an earthworm moves. After learning that the creature uses both circular and longitudinal muscle fibers to inch along, the researchers worked on creating a similar soft, peristalsis-driven system. A tiny battery and circuit board inside the tube works to heat the wire at certain points along the body, causing it to contract and stretch, and as a consequence, move along.
The absence of bulky, breakable parts means that Meshworm could be used to get into difficult-to-access places and navigate rough terrain. Next-generation endoscopes, implants and prosthetics are also cited as possible applications.