This robot eel glides through saltwater without making a sound

Even before Gore Verbinski’s disappointing recent horror movie A Cure for Wellness, we were pretty creeped out by eels. As if the real thing wasn’t unnerving enough, however, engineers and marine biologists from the University of California, San Diego, have created an eel robot that’s designed to swim silently through saltwater — using the same rhythmic, ribbon-like motions as its natural counterpart.

“The robot is powered by artificial muscles that contract and expand when stimulated with electricity,” Caleb Christianson, a Ph.D. student at the Jacobs School of Engineering at UC San Diego, told Digital Trends. “By arranging these muscles and stimulating them in a certain sequence, we can generate forward propulsion.”

The eel robot does not carry an onboard electric motor. Instead, it is decked out with cables which apply voltage to both the water around it and to pouches of water inside its artificial muscles. The robot’s electronics deliver a negative charge to the surrounding water and a positive charge internally, thereby activating its muscles. These charges cause the muscles to bend. Fortunately for surrounding marine life, they are low enough current to be perfectly safe — so that any creature which hasn’t already fled in terror from the robot eel won’t find itself harmed by being in the same vicinity.

“Traditional robots for underwater exploration are typically powered by propellers or jets that generate a lot of noise, and are made out of rigid materials that may damage their surroundings if they were to bump into them,” Christianson continued. “Instead, the structure of our robot is completely soft, which reduces the risk of damage to the environment. The artificial muscles that we use are [also] silent, which allows the robot to swim without making any noise.”

Christianson noted that, right now, the project is still a proof-of-concept to demonstrate a means of underwater propulsion. In the future, the team hopes to add a variety of sensors and cameras, as well as optimize the design, so as to use the eel-bot for the purpose of underwater exploration.

A paper describing the work, “Translucent soft robots driven by frameless fluid electrode dielectric elastomer actuators,” was recently published in the journal Science Robotics.