Rolling Robot Inspired by Caterpillar

April 30, 2011— -- A robot that mimics one of the caterpillar's trickiest moves, escaping predators by curling into a wheel and rolling away, has been built by researchers from Tufts University. They hope this new form of locomotion will allow crawling bots to explore tricky danger zones, aid in search-and-rescue operations or even explore for hidden treasure.

"The most difficult part was getting it to actually do a roll," said Huai-Ti Lin, author of the new paper in Bioinspiration & Biomimetics. "There were a lot of trials, and a lot of sleeping in the lab. It was worth it. Once we got it to work, we optimized it and now we are matching the performance of the caterpillar."

Lin and colleagues at Tufts University department of biology, where he just completed his doctoral degree, spent three years designing the 10-centimeter-long "GoQBot" out of silicone rubber and alloy coils. While experts have built devices that crawl like caterpillars, it's the first time that they've figured out how to make a robot roll like one.

Turns out that several kinds of critters -- including a nocturnal Saharan spider, a shrimp-like stomatapod that lives in Panama, and a few kinds of caterpillars -- use rolling as a way of escaping trouble.

These movements take a lot of energy, but generate incredible speeds. Lin said he figured that using a rolling motion would allow the robot to cover greater terrain. The robot would also be able to explore tight spaces in a crawling mode.

"It's hard to get any speed out of crawling or inching," said Lin, now a postdoctoral researcher at Harvard University, who runs the blog Morphing Morphology.

The field of robotics has long looked to nature for inspiration, especially when it comes to finding new ways to walk across uneven surfaces. Howie Choset, associate professor at Carnegie Mellon University, has built a robot snake with a camera on its head that can crawl up a tree. The goal is to design devices that can take on search-and-rescue missions in crumpled buildings or explore caves and crevasses for lost items.

Choset says one of the biggest obstacles for this new class of robots is getting actuation, or motion, in three dimensions.

"We still need to build a robot that's capable of motions in confined spaces," Choset said from his office in Pittsburgh. There's also the problem of situational awareness. "Try driving a remote controlled car where you don't look at the car."

Despite these obstacles, there is one application that may already be taking off. Pittsburgh-based tech firm CardioRobotics -- a collaboration between researchers at Carnegie Mellon at Harvard Medical School -- is building small snake robots to help surgeons conduct minimally invasive surgery on the human body.