Manta Ray-Inspired Soft Robot Achieves Record Swimming Speed
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Researchers at North Carolina State University have developed a new soft robot that swims faster and with more control than ever before, drawing inspiration from the graceful movements of manta rays.
The robot,which can reach speeds of 6.8 body lengths per second – a important improvement over its predecessorS 3.74 body lengths per second – is capable of navigating both the surface and depths of the water column.
“Our new soft robot is more energy efficient and reaches a speed of 6.8 body lengths per second,” says jie Yin, corresponding author of the study and an associate professor of mechanical and aerospace engineering at NC State. “In addition, 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.”
Mimicking nature’s Design
The robot’s manta ray-inspired design features fins that are stable when spread wide.These fins are attached to a flexible silicone body containing an air chamber. Pumping air into the chamber forces the fins to bend, mimicking the downstroke of a manta ray’s fin. When the air is released, the fins snap back into their original position.”Pumping air into the chamber introduces energy into the system,” explains 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.”
Mastering Vertical Movement
The researchers meticulously studied the fluid dynamics of manta rays to understand how they control their vertical movement. This knowledge allowed them to replicate the manta ray’s swimming behavior in the robot.
“When manta rays swim, they produce two jets of water that move them forward,” says Jiacheng Guo, co-author of the paper and a Ph.D. student at the University of Virginia. “Mantas alter their trajectory by altering their swimming motion. We adopted a similar technique for controlling the vertical movement of this swimming robot. we’re still working on techniques that will give us fine control over lateral movements.”
The robot’s downward jet is more powerful than its upward jet,allowing it to rise when flapping its fins quickly. Slowing down the actuation frequency causes the robot to sink slightly between fin flaps,enabling it to dive or maintain its depth.
A Versatile and Efficient Design
The researchers demonstrated the robot’s capabilities in two ways. First,they successfully navigated the robot through a course of obstacles placed on the surface and floor of a water tank. Second, they showed that the untethered robot could haul a payload on the surface of the water, including its own air and power source.
“This is a highly engineered design, but the essential concepts are fairly simple,” says Yin. “And with only a single actuation input, our robot can navigate a complex vertical surroundings. We are now working on improving lateral movement, and exploring other modes of actuation, which will significantly enhance this system’s capabilities. Our goal is to do this with a design that retains that elegant simplicity.”
The research, published in the journal Science Advances, was funded by the National Science Foundation and the Office of Naval Research.
Manta Ray Robot Breaks Speed Record
Researchers at North Carolina State University have developed a soft robot inspired by manta rays that swims faster and with more control than ever before.
The manta ray-inspired robot achieves a speed of 6.8 body lengths per second—a substantial improvement over its predecessors, which could only manage 3.74 body lengths per second.
“Our new soft robot is more energy efficient and reaches a speed of 6.8 body lengths per second,” says Jie Yin, lead researcher and associate professor of mechanical and aerospace engineering at NC State.
Unlike earlier models confined to the surface, this innovative robot can navigate both surface and deep water.
Mimicking Nature’s Design
The robot’s design mirrors the manta ray’s graceful movements. Its fins,attached to a flexible silicone body containing an air chamber,bend when air is pumped into the chamber,mimicking the manta ray’s downstroke. Releasing the air triggers the fins to snap back to their original position, creating a pulsed swimming motion.
“Pumping air into the chamber introduces energy into the system,” explains Haitao Qing,a Ph.D. student at NC State and co-author of the study, “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.”
Mastering Vertical Movement
The team meticulously studied manta rays’ fluid dynamics to understand their vertical movement control. This understanding allowed them to replicate the manta ray’s swimming behaviour in the robot.
“When manta rays swim, they produce two jets of water that move them forward,” says Jiacheng Guo, a Ph.D. student at the University of Virginia and co-author of the study, “Mantas alter their trajectory by altering their swimming motion. We adopted a similar technique for controlling the vertical movement of this swimming robot.”
The robot achieves lift by flapping its fins quickly, creating a downward jet stronger than the upward jet.Slowing down the flapping frequency allows the robot to sink between fin flaps, enabling it to dive or maintain depth.
A Highly Versatile Design
The researchers demonstrated the robot’s capabilities by successfully navigating it through a course of obstacles placed on the surface and floor of a water tank. They also showcased the untethered robot hauling a payload on the water’s surface, including its own power source.
“We are now working on improving lateral movement and exploring other modes of actuation, which will substantially enhance this system’s capabilities,” says Yin.
The research, published in the journal Science Advances, was funded by the National Science Foundation and the Office of Naval Research.