We are familiar with the collective noun: a Shoal of Fishes. But what about a Shoal of Robo-Fishes? Researchers at the University of Washington in Seattle have programmed these robotic fishes to swim in schools. With this group behaviour, the robot fishes could be used to track marine pollutants or wildlife such as whales.

Swimming in a group allows more efficient data collection as they can cover a wider space of exploration as compared to just a single robot fish. However, the problem lies in coordinating these robot fishes to swim in a group.

So far, the team’s shoals only consist of three fish, either swimming in close formation where they all take the same heading, or dispersing to cover as wide an area as possible.

Each robot fish weighs 3 kilograms (6.6 pounds) and measures a half meter long (around 20 inches). A tail provides propulsion, along with two pectoral fins which also steer. These combine to let the fish swim in any direction, make tight turns and even go backwards.

Each fish has an onboard computer, depth sensor, and compass, as well as a radio transceiver. During the experiment which was restricted to a test tank, the three broadcast their headings to each other, and used any information received to adjust their own courses. The group remained coordinated despite about half of all information packets being lost – showing that the system is relatively robust.

As radio signals travel very badly in water, eventually the robotic fishes will be equipped with acoustic modems that uses sonar-like “pings” to communicate. The only issue with using this technology is that the sonar pings might interfere with the natural sonar used by the wildlife they are sent to track.

Via - New Scientist Tech