Robo-fish may monitor future oil spills

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.