Abstract: As marine resources gain increasing significance, the development of high-performance propulsion systems has become a critical area focus in underwater robotics research. Drawing inspiration from the unique symmetrical morphology and highly agile oscillatory propulsion of stingrays, a compact stingray-inspired robot has been developed. This robot integrates multiple functional components, including a head, an oscillating guide rod mechanism, a flexible undulatory fin propulsion mechanism, a hybrid-material drive shaft, a control system, an energy supply unit, and a tail. Driven by three motors, the hybrid-material drive shaft facilitates efficient power transmission to each undulatory propulsion unit at varying angles, ensuring consistent and stable propulsion. The robot demonstrates advanced maneuverability, capable of performing 360° rotations and S-shaped trajectories on the water surface. Furthermore, its flexible drive shaft enables three-dimensional underwater locomotion through precise control of bending angles. With a compact design measuring 270 mm in length, 270 mm in width, and 45 mm in height, and weighing only 346 g, the stingray-inspired robot achieves a maximum swimming speed of 0.617 body lengths per second (BL/s). This stingray-inspired robot holds significant potential for applications in underwater environmental monitoring, covert military reconnaissance, and aquaculture.

Key words: Stingray-inspired robot')">Stingray-inspired robot, Oscillatory propulsion, Mechatronic system design, Rigid-flexible couplingmechanism