Electronics-Free 3D-Printed Soft Swimming Robot With Pneumatic Oscillating Control for Efficient Undulating Locomotion

Soft robots, with their compliance and adaptability, are ideal for applications requiring continuously flexible, dynamic movement, making them promising candidates for underwater locomotion. However, current swimming soft robots often rely on electronic power sources and complex, laborintensive manufacturing, limiting their scalability and use in challenging environments. Recent advancements in 3D printing, particularly fused filament fabrication (FFF), offer a practical alternative for fabricating soft robots, enabling monolithic structures that require minimal assembly. In this work, we introduce a pneumatically powered, electronics-free swimming robot, fully fabricated from soft thermoplastic elastomer (TPE) using a desktop FFF 3D printer. Inspired by the morphology of the tadpole, our design incorporates a pneumatic oscillating controller as the “brain” and segmented actuators as the “tail,” enabling autonomous undulating propulsion without electronics. We demonstrate untethered operation using a portable CO₂ canister and characterize two robot configurations optimized for efficient swimming. The robots achieve controlled oscillation and effective underwater movement, reaching a maximum speed of 0.70 body lengths per second (BL/s). This electronics-free, 3Dprinted design represents a step forward in creating low-cost, accessible soft robotic platforms, suited for exploration in aquatic environments where electronics are impractical.