Engineer Robert Hogg’s spider sense is tingling, but he’s no superhero. His spider sense comes from an insect-like robot with a leg up on its wheeled counterparts because it walks instead of rolls.
The spider-bot, developed by Hogg and his team of researchers at NASA’s Jet Propulsion Laboratory (JPL), is the latest affordable addition to the agency’s robot family. Its legs step over obstacles, clamber up rocks and reach areas of interest that would normally be inaccessible to wheeled rovers that run on flatter paths.
Built from an off-the-shelf radio modem and computer processor chips, spider-bot uses a set of antennas as feelers to detect obstacles and terrain as it moves about on six spindly legs. And no exploration vehicle, however small, would be complete without mounted cameras to register surroundings.
The spider-bot prototype, which passed a recent field test at JPL’s Mars Yard testing grounds last month, is small and stands only seven inches (about 18 centimeters) high. It could fit in the palms of your cupped hands if you held it. But Hogg, a staff engineer with JPL’s Mobility Systems Concept Development Section, is confident that future refinements could bring it down to one-tenth that size.
"We started off trying to make the smallest, most inexpensive robot we could, but wanted to get the most power we could out of it too," Hogg told SPACE.com . "With that, we can dream up whatever applications we like for it."
Because of their size, spider-bots and similarly tiny remote-operated robots could survey comets, asteroids or moons; basically any small body in space. Including the International Space Station, Hogg added, where astronauts could use the mechanical critters as repair proxies by attaching tools to the legs that detect air leaks and other misfortunes.
Hogg said the next version of spider-bot will have self-sustaining legs that can be removed, interchanged or replaced with others. Depending on their intended use, he added, the machines could have anywhere from eight to 50 legs.
A web of spider-bots
One spider-bot is good, but when it comes to exploring the planets, the more the merrier, JPL researchers say. For example, look at the Pathfinder mission, which landed on Mars in July 1997 and deployed the small rover Sojourner.
"In that mission, we sent one robot to Mars, which drove around a few miles and looked at seven rocks," said Neville Marzwell, JPL’s manager of Advanced Concepts and Technology Innovations. "It cost $280 million."
The Pathfinder mission was considered a success, but to practically – and affordably – explore a planet, sending a horde of small, cheap robots that can talk to each other and relay information may be a better option.
Hogg and Marzwell believe the initial use of spider-bots would be as a communication relay, with a group of the little robots spreading out around a landing zone - or even a planet if there are enough of them - and relaying data back to a central hub. The hub then transmits the data to eager Earth-based scientists.
"A similar system would be useful on Earth during in the event of an urban disaster," Hogg said. "You could send 100 spider-bots in to relay information on the environment or identify the source of a chemical spill."
The spider-bots could even provide support to a larger Mars lander mission. In the Mars Yard tests, the spider-bot prototype followed a wheeled rover and substitute for a damaged radio relay.
"And it’s okay if you lose one or two of these little robots along the way because they're small and cheap," Marzwell added. The total cost of the spider-bot prototype’s parts was around $600, according to Hogg, who added that the cost could be less in later incarnations depending on their function and number.
Legs versus wheels
The inherent advantages to using legs instead of wheels seem apparent. A walking insect-like probe could climb the lip of an interesting crater, or step over jagged rocks that would otherwise be impassable.
But the tried and true method of robots-on-wheels has its finer points too, most noticeably in speed. "Wheels can get you going fast, and are better at low-energy levels," said Ronald Arkin, director of the Mobile Robot Laboratory at Georgia Institute of Technology. "And the use of wheels has been proven again and again."
And how smart a robot is also important. When it comes to intelligence, the spider-bot isn’t too bright. Onboard processors control leg movements and turns and Hogg handles the rest remotely. JPL and other robotics researchers are still working to develop a form of artificial intelligence for robots to make them self-sustaining and capable of simple decision-making.
"We need to get to a point where, if a robot is in an area where there is too much radiation or heat or something, it automatically knows to seek out shelter or a less irradiated area," Marzwell said.
Animal-bots in space
Spider-bot is only the latest member of NASA’s robotic zoo. The agency has already developed a snake robot that can wriggle its way into small cracks and grasp objects. There’s already a frogbot that hops from one location to another, and digging automatons, submersibles and even flying probes are all on the drawing board.
"The whole field of biomimetic robots is finally a well-accepted concept," said Arkin, whose lab researches colony-like robots based on bees and ants.
Basing robots on animals is logical, Hogg added, because of the obvious success the evolution of animals has had with respect to their ambulatory appendages.
"Legs in the animal kingdom are robust," he said. "I mean, they use them to go all over the place."
advertisement
