An innovative, eel-like robot developed by engineers and marine biologists at the University of California can swim silently in salt water without an electric motor. Instead, the robot uses artificial muscles filled with water to propel itself.
Researchers say the bot is an important step toward a future when soft robots can swim in the ocean alongside fish and invertebrates without disturbing or harming them. Today, most underwater vehicles designed to observe marine life are rigid and submarine-like and powered by electric motors with noisy propellers.
The foot-long robot is connected to an electronics board that remains on the surface. One key innovation was using the salt water in which the robot swims to help generate the electrical forces that propel it. The bot is equipped with cables that apply voltage to both the salt water surrounding it and to pouches of water inside of its artificial muscles. The robot’s electronics then deliver negative charges in the water just outside of the robot and positive charges inside of the robot that activate the muscles. The electrical charges cause the muscles to bend, generating the robot’s undulating swimming motion. The charges are located just outside the robot’s surface and carry very little current so they are safe for nearby marine life.
The robot was tested inside salt-water tanks filled with jelly fish, coral and fish at the Birch Aquarium at the Scripps Institution of Oceanography at UC San Diego.