Why 6-Legged Bots Rule [Archive]

Casey

10-27-2002, 03:32 PM

quote:Why 6-Legged Bots Rule

Forget two-legged bots — forget androids altogether. Bio-guru Robert Full has seen the future of robotics, and it's one part cockroach, one part millipede, one part Internet.

By Tom McNichol

Dean Kamen has a problem. Sometime next year, the celebrated inventor aims to start selling his much-hyped Segway Human Transporter to the general public, and already the sharks are circling. Whereas Kamen views his self-balancing scooter as a device that will revolutionize personal transport and even change how urban landscapes are planned, personal injury lawyers take one look at the Segway, aka IT, and see lunch. One group of Washington, DC, attorneys emblazoned this phrase across their Sue-It.com Web site: "Get ready to Sue-It!" The Segway's primary weakness — inherent in any upright device with wheels — is lateral instability. Hit a nasty pothole at top speed (12.5 mph) and the Segway is likely to do what far less sophisticated scooters do — toss you off the side. In May, a member of Atlanta's auxiliary police fell off a Segway while going up a driveway; he was hospitalized with a knee injury.

So who does Kamen turn to for ideas on how to improve the Segway's design? A biologist. As a professor of integrative biology, and one of the world's foremost authorities on animal locomotion, 45-year-old Robert J. Full is the master of a quirky facility at UC Berkeley that analyzes the biomechanics and physiology of the sort of crawlie creatures most people would rather step on than study. In July, Kamen invited Full to Manchester, New Hampshire — home of his company, Deka, and the Segway. The idea was not so much to solve the scooter's stability problem as to stimulate new ways of thinking about it. Moving forward without falling over is a skill nature has been working on for a long time.

At Deka, it's easy to tell who's in charge. Large paintings of Kamen grace the walls of the complex, all rendered by Dean's father, Jack, who was an illustrator for EC Comics during the 1950s. The paintings are done in different styles and reflect the many faces of Dean: Day-Glo Dean, Lord of the Manor Dean, Shaggy Engineer Dean. Kamen is a man who knows his place in history, even before history has figured it out.

FULL'S ADVICE TO DEAN KAMEN: REDESIGN THE SEGWAY WITH SPRAWLED LEGS, NOT WHEELS.

Not far from one of the largest paintings — a fluorescent Summer of Love Dean — Full is speaking to some 100 employees. Nearly all are wearing the same outfit as the Maximum Leader: denim work shirt, beat-up jeans, Timberlands. Full opens his presentation with what might be called a unified theory of legged locomotion. Having studied a diversity of animals, he and his colleagues have come to the surprising conclusion that no matter how many legs a creature has or how its legs are connected to its body — or what its skeleton is made of — all legs basically work the same way. Creatures don't progress smoothly as they run; rather, they alternately speed up and slow down, bouncing forward on springy legs like a pogo stick. "What happens when you poke these springy-legged animals?" Full asks the engineers. "How do they stabilize?"

To answer this, Full shows the Deka engineers a video of an experiment that looks as if it came from the mind of a juvenile delinquent. He strapped a cylinder filled with gunpowder to the back of a cockroach, ignited the charge, and then stood back. The charge exploded with a bright flash, but when the smoke cleared, the cockroach was already scurrying forward, as if nothing had happened. "The amazing thing was, we found that the cockroach could correct for this perturbation in less than 10 milliseconds," he says. That's faster than any signal could possibly make it to the brain and back, which means the cockroach's movement isn't a reflex at all. Instead, it's what Full refers to as a "preflex." "The animals appear to be self-stabilizing; the legs are essentially doing computations on their own," he says. "In a sense, the control algorithms were embedded in the form of the animal itself."

THERE'S NO REASON WE CAN'T IMPROVE UPON NATURE. FIRST OBSERVE, THEN THINK SIDEWAYS.

At this point, one of the Deka engineers sitting close by lets out a soft "Whoa."

By the end of Full's presentation, more than a few engineers sit slack-jawed in their chairs. ("You could hear a pin drop," Kamen later recalls.) Full never mentioned the Segway in his presentation, but the implication is clear: The most stable scooter design would have sprawled legs, not wheels.

When the lights come up, Kamen is perched atop a Segway, spinning distractedly in tight circles. He looks intrigued, and at the same time, a bit miffed.

A couple of weeks later, I call Kamen to see how he's processed Full's message. "Bob Full is a guy who has a very different perspective than a lot of the guys here. I knew that just about more than anyone in the world, people would appreciate listening to his thoughts on how nature very elegantly accomplishes moving around," Kamen says. Which is not to say he's ready to go back to the drawing board on the Segway — yet. "For a nice, smooth surface, I'm not sure I agree that legs are better than wheels. Bob looks at nature's response to moving in its natural habitat, and I'm coming out with man's response to living in a man-made habitat," Kamen explains. "Am I wedded to wheels? For now, of course. But the day you stop having an open mind, you're old."

A lot of people are picking Bob Full's brain these days. With a genial nature wrapped around a mind as quick as a lizard's tongue, Full is a widely respected for his biological insights. He's even more influential as a lateral thinker, adept at making connections across seemingly unrelated disciplines. His ability to blend hard science with a sense of fun has made him a favorite on the lecture circuit. For the last few years, he has been among the most popular speakers at TED, the Technology, Entertainment, and Design conference in Monterey, California. Pixar hired him as a consultant for A Bug's Life, tapping Full's research to help animators express the various characters' personalities, and get them to interact realistically with their environment. Full's meticulous deconstruction of the way creatures, particularly arthropods, move and maintain stability is having a profound effect on a host of other fields, from engineering and industrial design, to animation and, especially, robotics. Because of Full's work at UC Berkeley's Poly-Pedal Laboratory (Pedal stands for Performance, Energetics, and Dynamics of Animal Locomotion), the robots of the future will probably move not like bipedal humanoids but more like crabs or cockroaches.