The World’s Fastest Swimming Robot
Inspired by the fins of a manta ray, researchers at NC State University have engineered a soft robot that can swim even faster than its record-breaking predecessor.
“Two years ago, we demonstrated an aquatic soft robot that was able to reach average speeds of 3.74 body lengths per second,” says Jie Yin, corresponding author of a paper on the work and an associate professor of mechanical and aerospace engineering at NC State. “We have improved on that design.”
Yin says the new soft robot can reach an average speed of 6.8 body lengths per second and is more energy-efficient. Plus, the new robot can swim underwater.
“The previous model could only swim on the surface of the water. Our new robot is capable of swimming up and down throughout the water column,” Yin says.
The new swimming robot’s fins are shaped like a manta ray’s. Attached to a flexible body made of silicone, the fins can flap but remain stable when fully spread out. The robot’s body has an air chamber that when inflated, forces the fins to bend — similar to a manta ray’s down stroke. And when the air is released, the fins snap right back into their initial position.
“Pumping air into the chamber introduces energy into the system,” says Haitao Qing, first author of the paper and a Ph.D. student at NC State. “The fins want to return to their stable state, so releasing the air also releases the energy in the fins. That means we only need one actuator for the robot and allows for more rapid actuation.”
Qing says their compressed-air power system also helps it swim up and down — not just forward, like the first model. When the robot’s wings are at rest, Qing says, the air chamber is empty, which decreases buoyancy; and the faster it flaps its fins, the fuller the air chamber becomes — increasing buoyancy.
The researchers showed their soft robot could navigate an underwater obstacle course (see video above) and was also strong enough to haul a payload along the surface.
“This is a highly engineered design, but the fundamental concepts are fairly simple,” Yin says. “And with only a single actuation input, our robot can navigate a complex vertical environment.”
The paper, “Spontaneous Snapping-Induced Jet Flows for Fast, Maneuverable Surface and Underwater Soft Flapping Swimmer,” was published in Science Advances and co-authored by Yinding Chi and Yaoye Hong, former Ph.D. students at NC State, and Daniel Quinn and Haibo Dong of the University of Virginia.
This article is based on a news release from NC State University.
