Recently, a robotic impostor swam through the crystal
blue waters off Fiji, blending in with the fish teeming around the coral reefs.
Unlike the Cylons in Battlestar
Galactica, however, this infiltrator was on a peaceful mission.
In a new study published in Science Robotics, researchers at
MIT unveil what they say is the most advanced robotic fish of its kind ever
built. Armed with a camera and a lifelike wiggle, the device could one day help
biologists monitor the health of marine habitats without stressing out their
aquatic denizens.
The Soft Robotic
Fish, SoFi for short, is 18.5 inches long from snout to tail and weighs about
3.5 pounds. It can dive 60 feet underwater and is powered by enough juice for
about 40 minutes of exploration.
WHY THEY DID IT
As climate change
and overfishing wreak havoc on oceans, scientists are racing to study marine
life in detail. But scuba-diving humans don't exactly blend in, which can make
it hard to watch some animals up-close. SoFi could act as marine biologists'
unobtrusive eyes and ears.
“When we were
designing the robot, we tried to make sure that it's moving to conserve the
life we're trying to observe,” says co-author Joseph DelPreto.
HOW THEY DID IT
To build better
aquatic robots, researchers have mimicked tuna,
jellyfish, and lobsters, and they've also built robots out of
pliable materials, such as the
squishy “octobot.”
“There will be a revolution in some fields with soft
robots,” says SoFi's co-creator Robert Katzschmann, a
Ph.D. candidate at MIT's Computer
Science & Artificial Intelligence Lab. “It may be for underwater
locomotion, but also walking robots or grasping robots. This whole field will
see changes.”
Since 2014, MIT
roboticist Daniela
Rus and her students, including Katzschmann and DelPreto, have
built various prototypes of
robotic fish. But these early versions of SoFi couldn't be controlled remotely,
nor could they withstand dives more than three feet underwater.
Now, Katzschmann
and his colleagues have ruggedized SoFi and reinvented its buoyancy control
system. They also gave SoFi a remote control, letting a scuba diver drive it
from up to 50 feet away. To work in water, the system uses pulses of ultrasound
to communicate. It's controlled by a waterproofed retro
gamepad that DelPreto designed.
WHAT THEY FOUND
So far, SoFi's
disguise might be working. During the recent test dives around Fiji, reef fish
swam within inches of SoFi without being obviously spooked. For now, the robot
interloper recorded only video, but its creators envision adding other sensors,
such as thermometers.
Future versions
of SoFi will also improve the fish's swimming and vision, and its creators say
they're sketching out plans for SoFi “swarms”: schools of artificial fish set
loose to monitor ocean health, perhaps recharged by solar-cell platforms
floating on the water's surface.
