A groundbreaking aquatic robot, inspired by Manta rays, has shattered the world record for the fastest swimming soft robot. Developed by a team of engineers from North Carolina State University and the University of Virginia, this robot achieved speeds of 6.8 body lengths per second, equivalent to 156.4 mm per second or approximately 0.35 mph. This achievement surpasses the previous record of 3.74 body lengths per second set by the same researchers. The team, whose findings were published today in Science Advances, shared with Popular Science that this new robot design could be instrumental in future deep-sea exploration endeavors.
The engineers aimed to create a fast, energy-efficient, and highly maneuverable soft aquatic robot, drawing inspiration from nature. Instead of mimicking fast fish like Marlins, they turned to Manta rays, specifically focusing on their unique “wing-like pectoral fins.”
North Carolina State PhD student and co-author of the paper, Haitao Qing, expressed his fascination with the energy-efficient propulsion mechanisms of rays and other marine creatures. He noted that these biological designs are inherently optimized for tasks like navigating through unstructured environments, a challenge traditional rigid robots often face. Observing the elegant flapping motions and swimming patterns of Manta rays, Qing realized that their movements aligned perfectly with the objectives of soft robotics.
“Manta rays became a natural source of inspiration because of their unique swimming mechanics, which combine efficiency, speed, and maneuverability,” Qing explained. “Their wing-like pectoral fins generate oscillatory motions that are not only graceful but also highly effective for propulsion, allowing them to glide effortlessly through water surface and underwater.”
Video: Researchers designed a soft-bodied robot with flapping fins that spontaneously snap back to their initial state. Credit: Haitao Qing, North Carolina State University
Two flaps for the price of one
Taking inspiration from Manta rays, the engineers crafted a swimming robot composed of a flexible silicone body with fins resembling those of rays. This new robot, based on their previous design, introduced a “monostable snapping mechanism.” While previous versions required compressed air to flap the wings in both directions, this updated approach uses air to flap the wings once, after which they passively snap back during the recovery stroke. The result is a simpler, more energy-efficient swimming robot.
“This simplification enhanced energy efficiency, reduced mechanical complexity, and increased overall swimming speed,” Qing elaborated.
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Refinements to the robot’s wing design, incorporating a new geometry for improved speed and efficiency balance, were made. The adoption of a single-input pneumatic system enhanced control and adaptability to environmental changes. Adjustments in buoyancy enabled the robot to swim at different depths in the water.
Manta ray robots could explore oceans and survey marine life
The researchers navigated the soft swimmer through two underwater obstacle courses, one near the surface and one deeper in a water tank. Remote control was used to guide the robot, adjusting the wing flapping frequency with the pneumatic control system. The Manta ray-inspired design facilitated the robot in surpassing obstacles and achieving a record-breaking performance for a soft-bodied robot. Jie Yin, a student at North Carolina State University, mentioned plans to enhance the robot’s lateral movement and incorporate new actuation models for propulsion.
“Our aim is to maintain this elegant simplicity in the design,” Yin emphasized.
Qing highlighted the beauty of the robot’s design in its simplicity and envisioned scenarios where such swimming robots could be utilized for extended deep-sea exploration, marine surveillance, or monitoring water quality for environmental indicators. This design is not limited to oceans; Qing suggested that a similar flapping wing approach could be adapted for robots on land and in the air.
