The Velveteen Robot

The Emerging Field of "Soft Robotics"
Courtesy MIT

Researchers at MIT, Harvard, and Seoul National University have created a robotic worm. “So what?” you ask. They’re also making robotic horses—and robot hummingbirds, for goodness sake.

What’s promising about the new robot worm, though—the Meshworm, as it’s called—is that it’s a different kind of robot.

Robots are machines, and we’re accustomed to their looking like machines—with joints and pumps and gears and hinges made of metal or rigid plastic. The Meshworm, being a worm, is flexible. It works like a muscle rather than a clock, undulating along the ground with the same peristaltic motion our esophagus performs when we swallow food. It’s an example of the still-emerging field of “soft robotics.”

The Meshworm’s movements are modeled almost exactly on that of the earthworm. The researchers made it by winding a wire of a special memory alloy around a mesh tube. The wire, which is able to contract and expand in different segments along its length when a current is run through them, works as a muscle, squeezing the mesh in the ripples. Anyone who’s ever hunted night crawlers should be familiar with this process. Because it’s soft, the worm can fit through holes smaller than the diameter of its body, and when the researchers stomped on it, it didn’t break, but was able to keep wriggling along the floor. Sangbae Kim, a mechanical engineer at MIT who led the Meshworm project, says he believes the technology could be used to make endoscopes and implants, among other devices.

Soft robots haven’t reached the level of complexity of their more rigid brethren, but the idea is that to work in the world outside the lab, softness is a virtue. It’s an efficient way to deal with uneven landscapes and tight corners. And soft robots are more natural for humans to interact with—easier, literally, to handle, without sharp corners and pinching hinges. Other labs are working on soft robots, including teams at Carnegie Mellon and the private R&D firm Otherlab, creating inflatable robots: “pneubotics.”

Even hard robots will need to be soft in parts if they’re going to develop a real sense of touch. “Just feel your palm,” Kim says. “That is softer than any rubber you’ve seen in this world.”