Independent Actuation of Multiple Microrobots via Copper Foil-Based Electromagnet Grid

This paper presents a low-cost compact design for copper-foil-based electromagnetic coils that generate localized magnetic fields to actuate ferromagnetic microrobots (100-200 $\mu \mathrm{m}$). The coils are fabricated by helically winding fine copper foils around a mild steel pin, creating compact, efficient inductive structures capable of producing magnetic fields up to 150-200 Gauss. We propose a $3 \times 3$ electromagnet grid platform for dynamic, programmable control of single or multiple microrobots. The system's performance is validated through simulations and physical experiments in water, synthetic oil, and glycerin, demonstrating its versatility across varying viscosities and biocompatible environments. Predefined motion patterns, including square, S-shaped, and triangular trajectories, along with the independent actuation of two microrobots performing distinct tasks, highlight the platform's potential for high-precision, high-throughput microrobotic applications in biomedical and industrial fields.