Researchers have developed the fastest swimming soft robot yet, inspired by the graceful movements of manta rays.
The new robot, created by a team from North Carolina State University (NC State) and other institutions, can swim at an impressive speed of 6.8 body lengths per second—nearly twice as fast as the team’s previous model.
The study, published in Science Advances, highlights how studying nature can lead to breakthroughs in robotics.
The soft robot is designed with fins shaped like those of manta rays. These fins are attached to a flexible silicone body with an air chamber inside.
By pumping air into the chamber, the fins bend downward, mimicking the motion of a manta ray’s fin stroke.
When the air is released, the fins naturally snap back to their original position, creating a powerful and efficient swimming motion.
“We only need one actuator to make the robot move, which makes the system more energy-efficient and faster,” says Haitao Qing, the study’s first author and a Ph.D. student at NC State.
The robot also mimics how manta rays move vertically in the water. By adjusting the frequency of its fin flaps, it can swim toward the surface, dive downward, or maintain its position in the water column.
Manta rays swim by producing two jets of water that propel them forward. They change their direction by altering their swimming motion. The researchers adopted this technique for the robot, using computer simulations and experiments to refine its movements.
The team discovered that the robot’s downward jet is stronger than its upward jet. If the fins flap quickly, the robot rises due to increased buoyancy from the air-filled chamber. Slower flapping allows it to sink slightly between strokes, enabling controlled vertical movement.
Another clever feature is the robot’s use of compressed air, which affects its buoyancy. When the air chamber is empty, the robot is less buoyant, helping it sink. This balance between air pressure and movement lets the robot efficiently navigate different water depths.
The team tested the robot in two scenarios: navigating an obstacle course in a water tank and hauling a payload across the water’s surface. In both cases, the robot performed well, showcasing its ability to handle complex tasks with a simple, efficient design.
“Our robot is highly engineered but built on simple concepts,” says Jie Yin, the study’s lead researcher and an associate professor at NC State. “We’re now working to improve its lateral movement and explore new actuation methods to make it even more versatile.”
This manta ray-inspired robot is not only a record-breaking innovation but also a step forward in creating efficient, nature-inspired technologies for underwater exploration.
Source: North Carolina State University.
