Tag Archives: built
#435722 Stochastic Robots Use Randomness to ...
The idea behind swarm robots is to replace discrete, expensive, breakable uni-tasking components with a whole bunch of much simpler, cheaper, and replaceable robots that can work together to do the same sorts of tasks. Unfortunately, all of those swarm robots end up needing their own computing and communications and stuff if you want to get them to do what you want them to do.
A different approach to swarm robotics is to use a swarm of much cheaper robots that are far less intelligent. In fact, they may not have to be intelligent at all, if you can rely on their physical characteristics to drive them instead. These swarms are “stochastic,” meaning that their motions are randomly determined, but if you’re clever and careful, you can still get them to do specific things.
Georgia Tech has developed some little swarm robots called “smarticles” that can’t really do much at all on their own, but once you put them together into a jumble, their randomness can actually accomplish something.
Honestly, calling these particle robots “smart” might be giving them a bit too much credit, because they’re actually kind of dumb and strictly speaking not capable of all that much on their own. A single smarticle weighs 35 grams, and consists of some little 3D-printed flappy bits attached to servos, plus an Arduino Pro Mini, a battery, and a light or sound sensor. When its little flappy bits are activated, each smarticle can move slightly, but a single one mostly just moves around in a square and then will gradually drift in a mostly random direction over time.
It gets more interesting when you throw a whole bunch of smarticles into a constrained area. A small collection of five or 10 smarticles constrained together form a “supersmarticle,” but besides being in close proximity to one another, the smarticles within the supersmarticle aren’t communicating or anything like that. As far as each smarticle is concerned, they’re independent, but weirdly, a bumble of them can work together without working together.
“These are very rudimentary robots whose behavior is dominated by mechanics and the laws of physics,” said Dan Goldman, a Dunn Family Professor in the School of Physics at the Georgia Institute of Technology.
The researchers noticed that if one small robot stopped moving, perhaps because its battery died, the group of smarticles would begin moving in the direction of that stalled robot. Graduate student Ross Warkentin learned he could control the movement by adding photo sensors to the robots that halt the arm flapping when a strong beam of light hits one of them.
“If you angle the flashlight just right, you can highlight the robot you want to be inactive, and that causes the ring to lurch toward or away from it, even though no robots are programmed to move toward the light,” Goldman said. “That allowed steering of the ensemble in a very rudimentary, stochastic way.”
It turns out that it’s possible to model this behavior, and control a supersmarticle with enough fidelity to steer it through a maze. And while these particular smarticles aren’t all that small, strictly speaking, the idea is to develop techniques that will work when robots are scaled way way down to the point where you can't physically fit useful computing in there at all.
The researchers are also working on some other concepts, like these:
Image: Science Robotics
The Georgia Tech researchers envision stochastic robot swarms that don’t have a perfectly defined shape or delineation but are capable of self-propulsion, relying on the ensemble-level behaviors that lead to collective locomotion. In such a robot, the researchers say, groups of largely generic agents may be able to achieve complex goals, as observed in biological collectives.
Er, yeah. I’m…not sure I really want there to be a bipedal humanoid robot built out of a bunch of tiny robots. Like, that seems creepy somehow, you know? I’m totally okay with slugs, but let’s not get crazy.
“A robot made of robots: Emergent transport and control of a smarticle ensemble, by William Savoie, Thomas A. Berrueta, Zachary Jackson, Ana Pervan, Ross Warkentin, Shengkai Li, Todd D. Murphey, Kurt Wiesenfeld, and Daniel I. Goldman” from the Georgia Institute of Technology, appears in the current issue of Science Robotics. Continue reading
#435691 Squeezing Rocket Fuel From Moon Rocks
Illustration: John MacNeill
Engineers and Architects Are Already Designing Lunar Habitats
Squeezing Rocket Fuel From Moon Rocks
Robots Will Navigate the Moon With Maps They Make Themselves
Kim Stanley Robinson Built a Moon Base in His Mind
The most valuable natural resource on the moon may be water. In addition to sustaining lunar colonists, it could also be broken down into its constituent elements—hydrogen and oxygen—and used to make rocket propellant.
Although the ancients called the dark areas on the moon maria (Latin for “seas”), it has long been clear that liquid water can’t exist on the lunar surface, where it would swiftly evaporate. Since the 1960s, though, scientists have hypothesized that the moon indeed harbors water, in the form of ice. Because the moon has a very small axial tilt—just 1.5 degrees—the floors of many polar craters remain in perpetual darkness. Water could thus condense and survive in such polar “cold traps,” where it might one day be mined.
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Water Water Everywhere: Finding rich deposits of ice and extracting it should be possible but will be technically challenging for lunar settlers. Illustration: John MacNeill
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Mapping the Moon: Several lunar missions have produced strong evidence of water ice. A NASA instrument called the Moon Mineralogy Mapper (M3) found indications of water ice on the permanently shadowed floors of some polar craters. However, the measurements suggest that only a small fraction of cold traps contain ice [colored areas], and that the ice is probably mixed with lunar regolith. Data source.
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Rover-Mounted Drill: The most straightforward strategy for extracting water from polar ice deposits uses a rover-mounted drill. Honeybee Robotics has designed a Planetary Volatiles Extractor with a heated auger, which would cause any water ice in the drilled regolith to vaporize. That vapor would then move through a tube to a condenser unit, where it would turn back into ice. Illustration: John MacNeill
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Thermal Mining: A more ambitious scheme for extracting water from the moon is “thermal mining.” Researchers at the Colorado School of Mines have proposed redirecting the sun’s rays , using heliostats mounted on a crater rim. Water trapped in the regolith would turn into vapor that would be collected in a large tent, then vented into refrigerated cold traps, where it would condense as pure water ice. Illustration: John MacNeill
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Compressed-Gas Transport: To produce rocket fuel from water ice would require an electrolyzer to break the water into hydrogen and oxygen, which would then be compressed and stored for later use. In situ production would also require vehicles to transport the processed fuel to rocket pads. Illustration: John MacNeill
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