Posts Tagged ‘rovs’
Video: For More Maneuverable Undersea Bots, Researchers Mimic the Knifefish’s Cutting-Edge Fin Design
The black ghost knifefish isn’t like most fish. An Amazon basin-dwelling nocturnal predator that hunts via a weak electric field around its body, it maneuvers both forward and backward via a ribbon-like fin on its belly. Robotics engineers at Northwestern noted the fishes ability to quickly maneuver vertically in water and wanted to get to the bottom of the fin’s design, viewing it as a potential way to improve the maneuverability of undersea robots.
Computer simulations of the black ghost knifefish showed that the fish moved forward or backward using a single traveling wave along the fin on its underside—if the wave traveled one way down the fin it went forward, if the wave traveled the other way it went backward.
But when moving vertically, the researchers found the fin doing something unexpected: crashing two waves moving in opposite directions into each other. One wave traveling tail-to-head and one wave traveling head-to-tail would collide and stop at the center of the tail, canceling the horizontal thrust in either direction and turning it to downward thrust that allows the fish to move vertically.
Born of this unique finding was GhostBot, a small submersible boasting a biomimicking fin on its underside just like the black ghost knifefish. Thirty-two separate motors give independent control to the 32 artificial fin rays that are wrapped in an artificial lycra fin. GhostBot also boasts an electrosensory system similar to that of the real knifefish that, hopefully, will allow it to position itself as precisely as the real deal using it’s fin. Check out GhostBot working out its ribbon fin below.
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Meet the Robots On the Oil Leak’s Front Lines
Remotely operated robots are shooting video, carrying equipment, drilling pieces into place, and monitoring the flow of oil. BP has contracted with at least four robotics companies, including Oceaneering International Inc., Subsea 7 and C-Innovation, to do the work, according to .
Initially, the undersea robots were unimpressive, failing to that could have sealed the well from the surface. But since then, they cut the broken riser pipe and placed both containment domes over the spewing well. They’ve also provided the live video streaming across millions of TV screens.
Teams of humans on boats are controlling the robots, which have names like Maxximum, Hercules and Skandi Neptune. The human operators -- two for each robot -- drive using joysticks, but they can’t see where their undersea avatars are going. Even with headlights, the robots’ environment is almost completely dark, so they use sonar to gauge their proximity to objects.
The ROVs range in size from that of a small car to a big truck, although most of their bulk consists of foam intended to protect them from the intense pressures found at 5,000 feet below the surface. They remain connected to fiber-optic or copper tethers that enable communications, but sometimes ocean currents tangle or even break those lifelines.
The spill has shown the world how much hinges on the work of a team of robots, according to John Mair, global technology manager for the Scottish firm Subsea 7.
Here’s hoping they (and their human drivers) can handle the pressure.
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