Analysis of magnetic configuration and its effect on motion in magnetically actuated soft miniature robots within tubular confinement.

Abstract

Soft, magnetically actuated robots offer promising potential for medical applications due to their simple fabrication, controllability, cargo loading ability and flexibility. This research focuses on the design, modeling, and behavior of soft, millimeter-scale filamentous robots composed of Gelatin Methacrylate (GelMa) hydrogels and embedded with micromagnets for magnetic actuation. These robots are designed for navigation within the human urinary tract. The study investigates two distinct configurations: screw-like and fin-like robots, each responding differently to an external rotating magnetic field. The screw-like robots propel forward through synchronized helical motion, while the fin-like robots rely on interaction with surrounding surfaces for crawling motion. Experimental frequency response tests reveal that fin-like robots exhibit three times faster motion than screw-like robots in confined environments, reaching velocities of up to 18 mm/s. Additionally, the influence of micromagnet location inside the filaments on their propulsion dynamics is explored, highlighting the potential for optimized performance in medical applications requiring navigation through narrow channels, such as the ureter. Further optimization is proposed to enhance control and performance in more complex biological environments.

Supplementary information: The online version contains supplementary material available at 10.1007/s12213-025-00188-1.