For 14 years a research project funded by the European Union has been working to develop efficient underwater robots based on biological principles.
Now researchers say they've developed a robot fish controlled with the help of lateral line sensors that mimic the sensing organ found in nature.
In living fish -- and now in the robot version -- lateral line sensors create a flow "landscape" that helps them orient themselves, navigate and control their movements.
"So far flow in robotics is treated as a disturbance that drives the robots away from their planned course," researcher Maarja Kruusmaa of Estonia's Tallin University of Technology said. "We have shown that flow is also a source of information that can be exploited to better control the vehicle."
A fish robot with lateral line sensing can save energy by finding energetically favorable regions in the flow where the currents are weaker or by interacting with eddies so that they help to push the robot forward, the researchers said.
"It is similar to reducing your effort in the tailwind of another cyclist or reducing the fuel consumption of your car by driving behind a truck," Kruusmaa said.