With climate change and overfishing wreaking havoc on our oceans, it is becoming increasingly important for researchers to closely monitor our marine life. However, observing sea creatures up close is almost impossible since human presence scares the animals. Now, thanks to The Soft Robotic Fish, aka SoFi, researchers may not only be able to keep a close eye on the elusive creatures, but also uncover undersea secrets that have been eluding us for centuries.
Built by MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL), the snow white remote-controlled robot closely emulates real fish, complete with a flexible tail that flicks from side to side and two “fins.” Though not the first autonomous underwater vehicle (AUV) created to monitor the oceans, SoFi resolves many of the issues that have hindered the usefulness of previous robots.
AUV’s traditionally have had to be tethered to a boat because radio frequency communications do not work well underwater. To overcome the hurdle, CSAIL director Daniela Rus and her team used sound waves. The ultrasonic technology can travel greater distances allowing drivers, using a modified, waterproofed Super Nintendo controller, to pilot SoFi from up to 50 feet away. To ensure SoFi can freely move around the ocean and maneuver like a real fish, a hydraulic pump seamlessly transfers water from one balloon-like structure to the other through its soft rubber tail, while a controller fitted with a smartphone lithium polymer battery powers the robot through the ocean, unhindered by tethers or propellers. CSAIL Ph.D. candidate Robert Katzschmann, lead author of the study published in Science Robotics on March 12, says, “To our knowledge, this is the first robotic fish that can swim untethered in three dimensions for extended periods of time.”
Also limiting traditional AUV usefulness is the risk of collision. With an exterior made of silicone rubber and flexible plastic that keeps its inbuilt electronics dry, SoFi poses no such danger. “Collision avoidance often leads to inefficient motion, since the robot has to settle for a collision-free trajectory,” says Rus. “In contrast, a soft robot is not just more likely to survive a collision but could use it as information to inform a more efficient motion plan next time around.”
During test dives in Fiji’s Rainbow Reef, SoFi glided alongside the unsuspecting marine life at depths of 50 feet for up to 40 minutes at a time, capturing high-resolution photos and videos. Even more important, it was able to do so without causing any disturbance. The researchers say sometimes the fish would swim alongside the strange-looking robo-fish in curiosity, while at other times they appeared utterly oblivious of its existence.
While SoFi currently only records video, future versions will include sensors such as thermometers. The researchers also hope to make it more autonomous and envision a day when swarms of the soft robots, powered by solar cells, will follow fish around, allowing scientists to gain insights into schooling dynamics and monitor their population. “For us, this fish is magical," says Rus. "We imagine someday it might help us uncover more mysteries from the amazing underwater world that we know so little about."