I, Caterpillar: A New Wave of Robots Wriggles & Squirms into Existence

Were Isaac Asimov alive today, he would surely laugh at the simplicity of the idea….Robotic devices that mimic caterpillars and worms rather than relieving humans of mundane or stultifying repetitive tasks. Dr. Barry Trimmer of the Robotics Lab at Tufts University [1] www.nytimes.com/2007/03/27/science] is doing his best to make a robot that can slither along, burrow and flex almost like the real thing. Hopefully, these small, worm like machines will one day be used to locate landmines, and fix machinery in hard to reach places as well as finding a use in the diagnosis and treatment of disease. Dr. Trimmer, a neurobiologist, is fascinated with the idea of using small machines to fix larger ones and robots make such a reality possible, but not in the shape or form in which we have come to expect them in.
Conventional robots, no matter how well constructed have a limited range of motion because hard joints don't allow expanded angularity of movement. "Each joint adds exponential problems of control," says Dr. Trimmer. Consider the robotic arms of the space shuttle, perhaps the most advanced use of a robotic device at the present time. While these mechanized arms can achieve an astounding range of positions, each and every movement requires an incredibly complex feat of engineering.
Researchers chose to mimic the caterpillar because it has an efficacy in movement that is energy efficient and elegantly simplistic. The robotic caterpillar prototype consists of a silicone rubber exterior wrapped around hair-thin wires that form a zig-zag line extending the length of its artificial body. Dr. Trimmer's creation is essentially a hollow tube with wire springs that act as 'muscles'. The springs are fashioned from a shape-memory alloy, and when heated by electrical current, constrict. When the current is turned off they expand returning the pliable shell to its original shape. A rudimentary form of segmental locomotion to be sure, but they are moving and with nanotechnology such a popular field of interest at the moment, who knows what kind of 'freight' these little buggers will eventually carry and where they will carry it.
David Kaplan, a biomedical engineer at Tufts, is working on an alternate application to silicone rubber shell, hoping to adapt a material based on spider silk, which would be biodegradable. The operating system for these tiny robots is currently being developed. Unlike the intricate engineering software required to operate the robotic arms of the space shuttle, these squirming (and somewhat unnerving) inventions will have their movements coordinated by genetic algorithms that will make them capable of locomotion and simultaneous multi-tasking. According to Dr. Kaplan, if these little guys can be produced in volume and at an inexpensive cost of less than a dollar per unit, their uses can only benefit humanity. Dr. Kaplan predicts, "These cheaply produced machines, could be crammed into a canister and shot into a minefield. Their hollow tube bodies would contain a simple power source and a device to detect mines as they wriggle across the terrain at random, stopping when they detect a likely mine."[2] www.iht.com/articles/2007/03/27]
While detecting landmines isn't exactly rocket science, the people at NASA who actually do deal in rocket science, are looking to build their own version of a small moving robot that does not use a wheel mechanism for locomotion. NASA is seeking devices that can move in a number of different ways without relying on wheels. “Wheels are a marvelous invention, but they have their place,” said Peter Will, a U.S.C. researcher working on the NASA project. "Bicycling on sand is hard, he said, while walking on it is easy." [3] www.technovelgy.com/ct/Science] Perhaps the next mars probe will have a robotic caterpillar packed as a "Plan B" contingency, so if the wheels fall-off it can still wriggle it's way along the Martian landscape.

CatherineS
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[1] www.nytimes.com/2007/03/27/science/27robo.html?ex=1175832000&en=76788c41438243f3&ei=5070
[2] www.iht.com/articles/2007/03/27/business/robots.php
[3] www.technovelgy.com/ct/Science-Fiction-News.asp?NewsNum=953