[cnet.com] Propelled by a servo-actuated two-link tails and flapping pectoral
fins, a new breed of robofish programmed to swim in schools may soon be
used to track oil spills or wildlife such as whales, according to
researchers at the University of Washington in Seattle.
By mimicking a fish’s natural propulsion mechanics these "autonomous
fin-actuated underwater vehicles" are able to swim in any direction,
make tight turns, and even go backwards, researchers say. The
university is testing three of the vehicles in an indoor freshwater
tank equipped with a four-camera tracking system to supplement data
collected by onboard sensors.
One of their challenges is how to coordinate the artificial fish so
that they work together. But radio signals don’t travel well
underwater, forcing robots in previous experiments to surface
periodically to receive orders from central command or, worse, be being
linked by cable.
These fish are more independent–controlling and coordinating their own
actions using onboard microprocessor for collecting data and computing
control commands, a pressure sensor for gauging depth, and a 3D compass
all powered by NiMH rechargeable batteries. When they do need to
communicate with one another, they use sonar-like "pings" from acoustic
modems.
The three fish in this latest experiment kept it together despite
losing roughly half of the information packets, which shows the system
is relatively robust. "With a group of vehicles you can get more data
collection at the same time than with just one. You get better spatial
distribution and cover more area," Kristi Morgansen, a UW roboticist,
told New Scientist.
The military thinks it’s a good idea too. The U.S. Office of Naval Research
wants to fund its own fishy version that would use cameras to gather
data and then share the intel via sonar. Eh, herding whales sounds like
more fun.
