Metro

Meet SoFi, a new soft robotic fish designed by MIT researchers

MIT researchers have designed a small robot fish with a wiggling tail that they hope can mingle with real fish, offering marine biologists an insider’s view of underwater life.

In a study published in the journal Science Robotics, Massachusetts Institute of Technology graduate student Robert Katzschmann described creating SoFi (for “soft fish”), which can be controlled by a diver holding a glowing, waterproof Super Nintendo controller.

“Traditional robots are not that great at interacting with the real world,” Katzschmann said. “They’re usually rigid or metal, so we wanted to explore the space of using compliant, rubber-like materials.”

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The researchers, who work in MIT’s Computer Science and Artificial Intelligence Laboratory, initially started out the usual way, with big cylinder-like robots with thrusters latched to the side.

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“Everything was waterproof, but everything was rigid and hard,” Katzschmann said. “It didn’t feel like a good way of understanding how marine life interacts without disturbing them too much, so that got us into thinking about how to build a fish or underwater creature that would behave like its underwater counterparts.”

So they built SoFi, a foot-and-a-half-long robot powered by a lithium polymer battery that can navigate through 60-foot-deep waters and collect information with a camera. Video provided by MIT showed the robot’s tail swishing easily from side to side as it swam through the deep water.

Controlling a “fish.”
Joseph DelPreto
Controlling a “fish.”

In testing, “most of the real fish were not irritated by or even noticed SoFi, which is the whole point,” he said.

A diver swims as much as 30 feet away, controlling the robot, but Katzschmann said his team was working on a plan that would allow researchers to control SoFi from further away.

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“We wanted to show that a soft robot can be useful for actual applications,” he said. “Most soft robots just work as prototypes or simple experiments, but no one could really imagine what to do with them yet.”

The researchers envision that, in addition to opening a window on marine life, robot fish in the future might be able to lead swarms of fish away from known pollution sites, among other tasks.

The MIT team has already heard from marine biologists all over the world who want to work with SoFi, he said.

“To our knowledge, this is the first robotic fish that can swim untethered in three dimensions for extended periods of time,” he said in a statement. “We are excited about the possibility of being able to use a system like this to get closer to marine life than humans can get on their own.”

In testing, “most of the real fish were not irritated by or even noticed SoFi, which is the whole point,” Robert Katzschmann said.
Joseph DelPreto
In testing, “most of the real fish were not irritated by or even noticed SoFi, which is the whole point,” Robert Katzschmann said.

Elise Takahama can be reached at elise.takahama@globe.com. Follow her on Twitter @elisetakahama.