Snake Robots Tempt NASA MOFFETT FIELD, Calif. NASA has fallen prey to the temptation of the lowly snake and gone back to the garden for inspiration for its next generation of spacefaring robots.
A small group at NASAs Ames Research Center in the heart of Californias Silicon Valley is developing an independent robot that can crawl, coil, climb and grasp -- just like a serpent.
Snakebots could help explore other worlds, breaking into smaller segments to fan out across the surface before regrouping.
Ames scientists foresee a day when the biomimetic robots could be used to ferry and manipulate parts and tools on zero-gravity space construction sites, like the proposed Space Solar-Power Project. A twining, climbing snake, the scientists say, could wend its way into tight spaces inaccessible to astronauts in bulky spacesuits.
Snakebots could climb structures while carrying cargo, shown here in red, and then act as a robotic arm to perform construction or maintenance.
And robotic snakes could even help explore places like Mars, slithering across the planets surface no matter how rough and tumble it may be. There, a camera-equipped snake could plumb the planets nooks and crannies, places where a wheeled rover could never venture.
Elsewhere within NASA, scientists have, or are, developing snake robots that could crawl inside pipes to inspect them from within and others to probe the tightly packed recesses of the space shuttles payload bay.
"Its a very flexible platform," said Gary Haith, a computer scientist who heads the Serpentine Robotics Project at Ames.
Can your socket wrench climb scaffolding?
Haith said a snake robot could be equal parts locomotor and manipulator a power tool clever enough to pick up and crawl to a job site on its own, parts in tow, and then carry out whatever task is required of it.
On the Space Solar-Power Project, the robots could help assemble the proposed array of orbiting solar cells that would generate power to beam as microwaves to other spacecraft, or down to Earth.
The nimble robots could negotiate the forest of scaffolding needed to support the massive solar arrays, as would a real snake a tree. And simply by latching one end of itself onto the structure and maneuvering the other, the snake can quickly become a highly articulated robotic arm, Haith said.
NASA hopes the robots, like real snakes, could be adept climbers, scaling structures built in space
."You can imagine a team of these things being very general purpose at the same time as being very adaptable," Haith said.
Snake robots could also be put to work on projects like the International Space Station.
Scientists at NASAs Jet Propulsion Laboratory (JPL) in Pasadena, California are working on one such robot now. The snake, which could be unveiled as early as next month, may well become the ultimate plumbers helper.
"We have a snake robot that can go inside pipes, find leaks and seal them and go on its way," said Neville Marzwell, the advanced concepts and technology innovations manager at JPL.
The tiny snake, just 1 inch (2.5 centimeters) in diameter, could be used to inspect gas lines here on Earth as well. Marzwell said the snake could use the pressure of the gas within the pipeline to turn a tiny turbine to produce its own electricity.
Whither the slither
In terms of planetary exploration, snake robots could negotiate rocky terrain that would stop conventional rovers in their tracks. They could also crawl into and explore fissures, cracks and crevices all protected from harmful ultraviolet radiation that might harbor water ice and perhaps elusive traces of martian life.
"If you really want to find life, you have to go deep," Marzwell said.
Serpentine robots, as seamless and smooth as their real-life counterparts, would also be impervious to gear-jamming dust and caustic chemicals.
"From a packaging point of view, its very regular, its all totally encased, so you have a lot fewer contamination issues," said Hans Thomas, a computer scientist and member of the Ames project.
Break, explore, regroup, repeat
A single snake could improve several times over on a rover when it comes to making scientific observations.
"You can imagine them doing things where having a bunch of individuals is higher leverage than having just one big thing," Haith said.
One albeit long snake could break into multiple snakelets, which could fan out over a broad area of the martian surface to assay several rocks in the time it would take a wheeled rover to sample just one.
The snakesbots also could help explore other worlds, breaking into smaller segments to fan out across the surface before regrouping.
"In these cases many small robots may be useful to more rapidly explore a certain area," said Mark Yim, a senior member of the research staff at Xeroxs Palo Alto (Calif.) Research Center. "But if they are in a crater, a larger robot may be able to climb out where a smaller one could not. Here they could join up in order to traverse these difficult areas."
Yim has spent seven years working on snakelike robots, including reconfigurable versions that could alternately form the shape of a rolling hoop, walking spider or slithering serpent, all depending on the need.
The snakes charm
Snake robots would also be far more resistant to damage than a rover: by their very nature, the multi-segmented creations are hyper-redundant.
Even if one or more of the snakes links should conk out, the remainder like a string of Christmas lights with one or more burnt-out bulbs can continue to function.
And in a worst-case scenario, any broken segment could be removed and replaced.
"Its a bunch of repetitive modules, so you can just take one out and plug another one in," Haith said, explaining an impromptu surgery that a robot could conceivably even perform on itself.
Its the wiggle, not the worm
So why doesnt NASA already have snakes crawling every which way?
Because Mother Nature still has it beat.
"Making a snake move is deeply non-trivial," Haith said.
The project, like other projects elsewhere in the United States, Germany and Japan, has already succeeded in making snakes that can move with a variety of gaits, including side-winding, on pavement (see the short movies at right).
This time, with feeling
Next up is outfitting snakes with feedback mechanisms, including rib-mounted strain gauges, so they can respond dynamically to the world around them.
"It would have a pretty good sense of where its being touched and how hard," Haith said.
A touchy-feely robotic snake could climb a scaffold structure and even learn to burrow beneath the ground. A human controller could use a joystick to simply indicate a general direction of travel or destination and the snake could take over from there.
The snake could independently push off from rocks, wiggle between cracks and brace itself if it started to slip. Its gait would depend on whether it was slithering across sand, gravel or a hard surface.
By the end of the year, the team hopes to have a working snake with tiny micro-controllers at each joint and strain gauges at each rib that could execute dynamic gaits, switching, say, from a side-winding motion to lateral undulation, Thomas said.
Excuse me, is that a real snakeskin robot?
Eventually, scientists hope to build robotic snakes sheathed in artificial muscles called electroactive polymers (EAPs).
EAPs are simple, lightweight strips of deformable plastic coated with metal. When electrical voltage is applied to them, they can bend and flex like a muscle.
An EAP snake would eliminate the need for any moving parts or any other parts at all, other than its own skin and a power source and make for a highly resilient robot.
Thomas said he could imagine the snakes crashing down on Mars, like the Deep Space 2 microprobes were designed to do, bouncing a few times and then getting to work.
"Its basically throwing a rubber band down on the ground," Thomas said.
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