3D‐Printed Shark‐Inspired Soft–Hard Hybrid Underwater Robot With Buoyancy Control and Onboard Vision

Biomimetic underwater robots have attracted increasing attention as tools for aquatic exploration and environmental research, yet achieving compact systems that balance fabrication simplicity, propulsion efficiency, and three‐dimensional (3D) locomotion remains challenging. This paper presents a shark‐inspired underwater robot based on a 3D‐printed soft–hard hybrid design that integrates propulsion, buoyancy control, and onboard vision within a fully untethered platform (225 mm, 407 g). The system combines a rigid internal skeleton with a compliant outer skin, enabling both structural integration and large‐amplitude deformation for propulsion. The robot employs a pump‐driven buoyancy control mechanism that modulates body mass by ∼2.4%, enabling vertical locomotion and is expected to regulate depth without continuous thrust. Also, the robot achieves 3D locomotion, including forward swimming at ∼0.29 BL·s −1 , turning with radii down to 0.99 BL, and ascent/descent at ∼50 mm·s −1 . In addition, onboard monocular vision enables real‐time target tracking via closed‐loop control. This work introduces a reproducible soft–hard hybrid design framework that integrates propulsion and buoyancy control within a compact platform, providing a practical foundation for underwater robotic systems.