Engineers at the University of California San Diego have built a squid-like robot that can swim untethered, propelling itself by generating jets of water.
“Essentially, we recreated all the key features that squids use for high-speed swimming,” said Michael T. Tolley, a professor in the Department of Mechanical and Aerospace Engineering at UC San Diego. “This is the first untethered robot that can generate jet pulses for rapid locomotion like the squid and can achieve these jet pulses by changing its body shape, which improves swimming efficiency.”
The squid robot carries its own power source and is made mostly from soft materials such as an acrylic polymer, with a few rigid, 3D printed, and laser-cut parts. It can also carry a water-proof camera or a different type of sensor for underwater exploration. Soft robotics is used to ensure the safety of fish and corals, which can be damaged by rigid robots.
However, soft robots tend to move slowly and have difficulty maneuvering. The team of roboticists and computer simulation experts turned to cephalopods as a good model to solve some of these issues. The robot developed by the researchers draws water into its body while storing elastic deformation energy in the flexible ribs. It then releases this energy by squeezing its body and generates a jet of water to move.
In the laboratory tests at UC San Diego, the Squid Robot was able to achieve a speed of about 18 to 32 centimeters per second (roughly half a mile per hour), which is faster than most other soft robots.
“After we were able to optimize the design of the robot so that it would swim in a tank in the lab, it was especially exciting to see that the robot was able to successfully swim in a large aquarium among coral and fish, demonstrating its feasibility for real-world applications,” said Caleb Christianson.
The next step is to improve the robot’s efficiency and its ability to maneuver and go faster by reworking the nozzle that expels the water.