Design, modeling, and control of magnetically actuated rod-like soft robots: Propulsion in free space with viscous fluids and navigation in confined geometries

Abstract

This paper presents advancements in the design, fabrication, and performance evaluation of magnetically actuated soft robots in various fluidic environments. It features a simplified manufacturing process and uniform structural optimization. A numerical modeling approach was introduced for the preliminary evaluation of the propulsion performance of hydrogel-based, rod-like soft robots in a viscous Newtonian fluid under free space boundary constraints, which was later validated through experiments. Meanwhile, additional experiments in water with boundary constraints were also conducted to assess the robots’ performance under varying environments. The results highlighted the critical role of structural integrity, especially concerning propulsion performance in viscous fluids under different external magnetic fields. Moreover, experiments in confined mazes with boundary conditions demonstrated the robots’ controllability and flexibility in navigating complex environments, such as vessel-like structures. Our findings suggest future research directions, including enhancing material characterization to examine the correlation between material deformability and propulsion efficiency, improving control algorithms for dynamic environments, and exploring other motion strategies to increase application versatility.