A Magnetic-Driven Self-Rotation-Stabilized Miniature Swimming Robot.

Miniature swimming robots (MSRs) are crucial in fields like environmental science, industry, and healthcare, especially in accessing narrow underwater spaces. However, current disturbances and undercurrents in real waters can severely disrupt the trajectory and stability of the MSRs, preventing them from effectively completing their intended movements and maneuvers. To address this challenge, this paper proposes a magnetic-driven self-rotation-stabilized miniature swimming robot (MSMSR), inspired by the Dipterocarpus alatus seed rotation mechanism. The robot features a polyhedral deployable structure (PDS) with flexible joints and four inclined magnetized feet. These flexible joints enable energy accumulation for rapid swimming, while the PDS facilitates pulsating propulsion. The magnetized feet support rotational movement, allowing stable self-rotation swimming. Additionally, a resonance-driven strategy, based on the coupling of the robot's natural frequency with the magnetic field frequency, enhances its swimming performance. Experimental results show a maximum swimming speed of 43.7 mm/s and a maximum self-rotational angular velocity of 4.7 rad/s. When subjected to lateral water flow with a velocity of 150 mm/s, the robot stabilizes within 1.3 s. Furthermore, the robot can swim directionally into narrow spaces and accurately measure the pH value of the target water, highlighting its potential application in water environment monitoring and related scenarios.