Streamlined Robotic Manta Ray Swims Faster with a Simplified, Efficient Design

Just two years ago, a tiny robotic manta ray set a record as the fastest-swimming soft-bodied robot. Now, its upgraded successor has shattered that record while using less energy in the process.

The original 22.8-mm-long robot was developed by Assoc. Prof. Jie Yin and his team at North Carolina State University. It featured two flexible polyester wings resembling a manta ray’s, formed from a single curved bistable structure. Bistability allows a structure to maintain two stable positions without requiring energy—like a hair clip snapping between open and closed states.

Innovative Actuation Mechanism Enables Record-Breaking Swimming Speed

The robot’s bistable wing structure was flanked by soft silicone pneumatic actuators. When the top actuator inflated, it bent upward, pulling the wing structure to snap the wings downward. Deflating the top actuator and inflating the bottom one reversed this motion, snapping the wings upward. This alternating actuation allowed the robot to swim at an impressive speed of 3.74 body lengths per second, about four times faster than any previous soft-bodied swimming robot.

The new 68-mm-long design simplifies and improves this system. Yin’s team eliminated the bistable structure and bottom actuator, replacing them with a monostable wing design. The wings now default to a curved-down position when at rest. A single top pneumatic actuator inflates to snap the wings downward and relies on the elastic restoring force of the structure to pull them back up when deflated.

Enhanced Efficiency: Streamlined Design Doubles Speed and Reduces Energy Use

This streamlined mechanism reduces energy consumption, as only one actuator is needed per wing-flapping cycle. As a result, the new robot achieves an average swimming speed of 6.8 body lengths per second—nearly double the original speed—while using 1.6 times less energy.

Moreover, the updated design enables vertical movement by varying swimming speed. When flapping slowly, the robot spends more time with its fins at rest, reducing buoyancy as the air chamber empties. Faster flapping keeps the air chamber full longer, increasing buoyancy.

According to PhD student Haitao Qing, the lead author of the study, this feature could have practical applications. The team is now developing a steering mechanism, envisioning future uses such as ocean exploration and aquatic wildlife observation.

The robot’s enhanced efficiency and versatility mark a significant step forward in soft robotics, as shown in the video demonstration below.

Read Original Article: New Atlas

Read More: Scitke