Einstein Science Reporting for Kids
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American Association for the Advancement of Science

Resilient robots

Researchers have designed a robot that can sense and recover from damage to its own body, an ability that should help robots operate in new or dangerous terrain.

Animals can compensate for injuries by changing their movements. For example they can limp to favor a painful leg, or do more work with one limb than the other.

It's possible to program a machine to respond to a problem in a certain way, but when machines become damaged in unexpected ways, they generally break down. Researchers would like to send robots out to explore new environments, including other planets or the seafloor, but most of the time when you're exploring, you don't know what you're going to encounter.

So, the challenge is to design robots that can improvise in response to being injured, the way humans and other animals can. Josh Bongard of the University of Vermont and his colleagues have built a four-legged robot that can do just that.

"We never officially named it, but we usually refer to it as the Starfish robot, even though a real starfish has five rather than four legs," Dr. Bongard said. "Also, a real starfish is much better than our robot at recovering from injury, because it can actually regrow its legs."

First, the Starfish moves around in a simple environment, like a flat table, and observes its own motion using sensors in its joints. Then, it creates a "virtual" version of its body on its internal computer. As it explores, it constantly updates the model to account for any damage to its body, and it uses the model to "think up" new movements that are possible in its damaged condition.

When the researchers shortened one of its legs, for example, the robot responded by shifting its gait.

Dr. Bongard and his colleagues describe their research in the 17 November 2006 issue of the journal Science.

Dr. Bongard has been interested in robots since he was a kid.

"I used to draw a lot when I was younger, but instead of drawing animals or people, I was always drawing robots. Robots fascinated me from a young age, but I started to wonder why there were so many robots in movies and books, but so few real robots. Later, I came across a book about artificial intelligence (that is, how could we create machines that act intelligently) which explained that it is really hard to make robots act intelligently, because we know so little about intelligence in general," he said.