Snakes, Robots, and the War on Terrorism

It's mighty daunting to be called a "brilliant young innovator" whose "work and ideas are apt to change the world…a visitor from the future, living among us here and now." Talk about pressure.

But that's exactly what MIT's Technology Review Magazine called Howie Choset, mechanical engineer and roboticist at Carnegie Mellon University, when they named him one of their TR100's – this year's august group of 100 innovators under the age of 35.

But, the Office of Naval Research isn't surprised.

ONR science officer Phillip Abraham funds this young innovator because Choset's research involves development of a snakebot and other mechanical and control strategies for urban search and rescue, structure inspections, and repair on Navy platforms. Tom Swean supports his work on de-mining – the removal of land mines – and Behzhad Kamgar-Parsi supports him on basic robotic navigation. Choset's work falls in among ONR's enormous challenges in the war against terrorism.

"Consider the collapsed World Trade Center," says Abraham. "The magnitude of the devastation exceeded the available resources of urban search and rescue specialists, dogs, and sensors. In other situations, the pancake collapse of large structures prevents rescue workers from entering buildings due to fear of further collapse. But the biggest problem is simply that both people and dogs are usually too big to enter voids."

"With their enhanced flexibility and ‘reach' ability in convoluted environments, serpentine robots make sense," says Choset. "Look at their biological counterparts: snakes and worms. Snakes lost their legs in evolution because they got in the way when crawling through narrow passageways." Using beveled gears around its circumference, Choset's snakebots – just five centimeters in diameter – have many more degrees of freedom than conventional robots, and their hyper-redundant mechanisms (if one actuator fails, the mission goes on) enable them to thread through tightly packed spaces, while not disturbing the surrounding areas.

Biological snakes move by different cyclic forms of locomotion, or "gaits." Adapting these gaits to the mechanical snake enables the robots to maneuver through three-dimensional terrains. Choset's motion-planning algorithms allow his snakebots to autonomously sense and respond to everything they encounter.

But, major challenges still remain: mechanism design, path planning/control, and sensor integration. "We will continue to support Choset's exploration of novel technologies, such as electro-polymers for future designs as well as the investigation of sophisticated control algorithms," says Abraham. "Current serpentine path planners are rudimentary at best," says Choset. "These are ad-hoc planar solutions that will not work in complicated environments. My new efforts will build upon prior work in path planning to yield control paradigms for directing serpentine mechanisms through unknown three-dimensional spaces."

ONR has supported Choset's research since 1997. "ONR's Teresa McMullen really got my career started," acknowledges Choset.

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