Fish robots to find sunken ships, fix oil rigs

Here come robotic fishes that could help scientists improve underwater vehicles used to study fragile coral reefs, repair damaged deep-sea oil rigs or investigate sunken ships.

Inspired by electric black ghost knifefish of the Amazon basin, Illinois-based Northwestern University researchers have developed agile fish robots.

Current underwater vehicles are large and lack agility, which means that working close to living or man-made structures is nearly impossible.

"We have taken lessons learned from the knifefish about movement and non-visual sensing and developed new technologies that should improve underwater vehicles," explained Malcolm MacIver, a robotics expert from Northwestern University.

MacIver and colleagues have developed more than half a dozen robots based on the weakly electric knifefish.

A major motivation for creating the robotic models of the knifefish is to generate a better understanding of how the nervous system combines the acquisition of information with movement.

The black ghost knifefish hunts at night in the murky rivers of the Amazon basin using closely integrated sensing and movement systems.

It has the unique ability to sense with a self-generated weak electric field around its entire body (electrosense) and to swim in multiple directions.

The fish moves both horizontally (forward and backward) as well as vertically using a ribbon-like fin on the underside of its body.

"Future integration of electrosense and ribbon fin technology into a knifefish robot should result in a vehicle capable of navigating complex 3-D geometries in murky waters - tasks that are impossible with current underwater vehicles," informed MacIver.

He presented his work at the American Association for the Advancement of Science (AAAS) annual meeting in Chicago Feb 15.