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Robots can be used in many environments. Usually, the task of designing a robot is simplified by the fact that the environment is controlled and not particularly harsh - like in a factory assembly line. However, it immediately becomes a more difficult task when one has to design and built a robot for an extreme environment. Here are some examples we found.
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 Nomad, built and operated by the Robotics Institute at Carnegie Mellon University's, is a real beefy piece of work. Powered by an internal combustion engine, capable of autonomous navigation using GPS and stereoscopic camera, capable of 4-wheel independent driving and steering for tight maneuvering, this 725 kg monster is well equipped for any number of environments. In additional to its capabilities for getting around, Nomad also had an extensible arm with instruments on it for close-up science. Nomad was originally developed to test autonomous navigation and tele-operation technologies over rough terrain. Its first deployment was in 1997 in the Atacama desert of Chile. A subsequent deployment occurred later in Antarctica, where it was able to find and classify a number of meteorites out there on the ice.
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 The twin Mars rovers, Spirit and Opportunity, from NASA's Jet Propulsion Laboratory are very impressive pieces of work. Each weighs 174 kg, measures roughly 2.3x1.6x1.5-m, traveled interplanetary space and literally fell from the sky to land on Mars, and is packed with sophisticated cameras and instruments. In order to survive on the surface of Mars, the rovers must survive daily temperature swings of 130 C. In shield its electronics, batteries, and other important components, the rovers have a Warm Electronics Box, which is insulated with solid-silica aerogel and gold foil, contains a heating element and a heat-rejection system, and manages to keep the interior in the relatively comfortable temperature range of -40 to +40 C, usually well within a much smaller temperature range. While they only have a cruising speed of about 5 cm/sec, the rovers are off-road vehicles, capable of traveling with ease over uneven terrain, even uphill in loose sand (another picture). Each of the six independent wheels contains its own motor for driving, and the two front and two rear wheels have additional servomotors for turning. while each Rover receives its direction from the scientists and technicians here on Earth, it does rely on autonomous navigation to pick and maintain its route and coordinate its six wheels to work together. The rovers were built for a guaranteed operation life of 90-days on the surface of Mars. That clock started ticking in January 2004. However, the rovers were designed and constructed so well, and are aided by dozens of workers here on Earth, that the rovers have exceeded that mark five times over. While the rovers show signs of aging, they are still quite functional, and their mission has been extended indefinitely. How long can they last? It is not unreasonable to think that, with some good planning and positioning, the two rovers could survive the Martian winter through a sort of hibernation, or at least reduced workload, and continue producing useful data come next Martian spring. However, for all of their incredible scientific capabilities and adaptation for extreme environments, their pricetag of millions of dollars apiece and the need for an extensive support team here on Earth make them unattractive for our work.
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 Yet another creation of Carnegie Mellon's Field Robotics Center, Hyperion was built to execute sun-synchronous travel, autonomously and independent of any human control. That is, it will drive and orient itself such that its solar panel is always facing the sun. If the sun happens to be above the horizon 24 hours a day, as it was in the Atacama desert, circling around the horizon, then Hyperion's route over one day will likewise be circular (or elliptical). Of course, taking uneven ground and other obstacles into account, the robot's track over a day will wander quite a bit. Hyperion was not built for looks - it was developed rapidly and for mechanical simplicity. It has a rugged, lightweight frame and passively articulated steering with a single drive motor. Because the 24-hour austral sun of the Atacama desert does not get very high above the horizon, Hyperion's single solar panel is mounted almost vertically.
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A joint project between NASA and Carnegie Mellon's Field Robotics Center, the Dante robots were designed to descend down into the inferno. In 1992 Dante I (far left) descented down into the caldera of Mt. Erebus in Antarctica. In 1994 Dante II (left) did the same on Mt. Spurr, a volcano in the Aleutian Range. Their task was to descend down the sheer walls of the volcano's crater to sample high temperature gasses right from the source. This is, naturally, a very hazardous task for humans. Each eight-legged robot moved about like a spider or a crab - moving pairs of its legs at a time while the other legs remain planted to the ground, while a steel cable kept them from held them back - like rappelling. Dante had a tether that supplied it with power and commands while sending back video and data. A researcher told Dante where to go from a distance (at the volcano's rim or continents away), and the commands were translated into leg movements by an onboard computer. Dante's vision system allowed it to intelligently plan its path and avoid obstacles. While it's immediate purpose was the exploration of active volcanos, the Dante was a demonstration of how a similar robot could explore the difficult terrain of moons and planets.
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There are also several commercially available robots that are designed for extreme environments, semi-autonomous navigation, or overall ruggedness. Examples can be found from iRobot or Adept MobileRobots (we refrain from putting pictures up because, despite the free advertisement it would provide, the companies probably have some rather strict rules about image use, whereas we hope to have a little flexibility with government and academic institutions). While these present the appeal of being ready-to-go right out of the box, the reality would be anything but. There does not seem to exist a commercial robotic product that, even with retrofitting, could exist for months on end on the Antarctic plateau, utilize purely renewable power sources during that time, fit within our space or weight constraints, or provide the autonomy or communication capabilities we require in this project.
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