This Soft Robotic Fish Swims Just As Well As The Real Thing

Two of the greatest challenges facing robotics at the moment involve how the machines interact with their environment - especially when there are humans present. The ability to navigate through complex surroundings is a difficult one to instill, but far more pressing is the fact that most robots are, well...pretty solid. What that means is that if a robot should collide with a human, the latter's likely to end up with some pretty nasty injuries.

While some researchers have tried to solve this problem with elastic, artificial muscles, researchers at MIT's Computer Science and Artificial Intelligence Laboratory have taken a somewhat different approach. They've designed a soft robotic fish, with an outer shell of soft silicone.  This fish - which is perfectly safe for operation around humans - is capable of sophisticated, agile movements; it can basically swim just like the real thing. 

"Because of their bodies' capability to bend and twist, these robots are capable of very compliant motion. They're capable of very rapid, agile maneuvers, which pushes the envelope on what machines can do today," explained robotics lab director Daniela Rus. "They're also inherently safe to be around," she added.

The robot's computing power - which includes sensors and a wireless connection to a central server - is enclosed within a rigid head, protected by a hard shell. The rest of the body, meanwhile, is flexible and bendable. The whole array rather brilliantly achieves locomotion through carbon dioxide.

Enclosed within the fish's head along with its computational components are two CO2 canisters. These canisters each connect to a long, undulating channel; one on each side of the robot's body. In order to move the body, a canister will open to different diameters for different durations, producing an array of specific movements. This unique form of movement allows the robot to attain a surprising degree of accuracy in its motion; it can perform a one hundred degree escape turn in about a tenth of a second, just like a real fish. 

Because of this, Rus and her colleagues are presenting the fish as a proof-of-concept for the nascent discipline of soft robotics. 

"The maneuver is so fast and it's got such high body curvature that it shows that soft robots might be more capable in some tasks," said the robot's designer, MIT electrical engineering graduate student Andrew Marchese.

The main problem with Marchese's fish at the moment is that it's not necessarily built to last. After about twenty-five escape movements, it runs out of fuel. He's already working on a solution for that, though: he's currently planning a second version that uses pumped water instead of carbon dioxide to inflate the tail channels. That model, he estimates, would be able to swim constantly for around thirty minutes or so. 

At this point, some of you are probably trying to work out what the big deal is. Why is a robotic fish so exciting? Simple: fascinating nature of the design aside, this soft robot could signify a complete design overhaul in traditional robotics. 

If we could work out how to incorporate the concept into larger, land-based robots, we could potentially send the efficiency through the roof. Robots could easily pursue more efficient forms of motion to accomplish their tasks, free of the constraint that they never collide with a human. Pretty cool, right?