First Robotic Fish Capable of Untethered Swimming in the Ocean


Photo by: Geerati Nilkaew via 123rf


Monitoring and documenting marine life is not an easy task, especially if scientists are dealing with elusive animals because current technologies cannot document all of them up close. To address this issue, researchers at the Massachusetts Institute of Technology built a robotic fish that can swim the ocean wirelessly, which may soon help the documentation of marine animals

SoFi: The Robotic Fish Reporting

Computer scientists at the Computer Science and Artificial Intelligence at MIT created SoFi, a robotic fish, which can swim along with real fish in the ocean. Test dives showed that SoFi can swim to more than 50 feet of depth for up to 40 minutes. It can swim in a straight line, turn left or right, and dive up or down, and is capable of manipulating its own buoyancy, the upward force exerted on objects submerged in liquids.

Compared to current autonomous underwater vehicles, SoFi has a simpler and lighter overall design. The robotic fish is equipped with a fisheye camera, a motor, and a lithium battery similar to the ones used in smartphones. Researchers can make SoFi swim using a waterproofed Super Nintendo controller and a custom acoustic communications system.

In the point of view of SoFi, swimming is handled by several mechanisms. The motor pumps water into two chambers that resemble balloons, located in the tail of the robot. When one chamber expands, it bends and flexes to one side and when the actuators push the water to the second chamber, it bends and flexes to the other direction. The result is a replica of how real fish swim in the water.

“To our knowledge, this is the first robotic fish that can swim untethered in three dimensions for extended periods of time. 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,” expressed Robert Katzschmann, the lead author of the study from CSAIL.

SoFi is made of silicon rubber and flexible plastic produced using 3D printing technology. The robot also has a small amount of baby oil in the machinery to reduce the chance of water leaking. The researchers plan to upgrade SoFi, such as increasing the swimming speed by tweaking certain parts, and installing an onboard camera so it can follow real fishes.