Independent Control of Multiple Microrobots Based on Coil Array Magnetic Actuation System

Independent control of magnetic microrobot teams is a major challenge in the field of micro/nano manipulation. In this work, we introduce a coil array magnetic actuation platform that can generate a series of localized magnetic fields for parallel actuation of more than one microrobot for cooperative tasks. An optimized coil structure is first designed to produce uniformly distributed magnetic fields, which lies in accurate and flexible control of microrobots. Then, a current calculation scheme for the coil is established, based on the visual feedback, discrete closed-loop motion control of multiple microrobots between any two equilibrium points is realized. Subsequently, considering the physical and actuation constraints associated with the system, we apply a conflict-based search path planning strategy that add distance limits to generate collision-free paths for all microrobots. Finally, the developed system is tested with extensive physical experiments. The results impressively demonstrated the effectiveness of the devised platform and the proposed methods.