An Equilibrium Analysis of Magnetic Quadrupole Force Field With Applications to Microrobotic Swarm Coordination

Controlled microrobots in fluidic environments hold promise for precise drug delivery and cell manipulation, opening new ways for personalized healthcare. However, coordinating magnetic microrobot swarms presents significant challenges due to the complexity of the associated actuation mechanisms. While existing methods to achieve motion differentiation in collections of microrobots rely on design variations among them, the work reported here applies to homogeneous collectives and enables them to be steered as a whole or in fragments, by means of a common externally generated force field. This paper contributes to an emerging set of methods that enable swarm control through manipulation of these force fields. This paper in particular exploits the nature of force field equilibria in a quadrupole workspace configuration as a means of steering the swarm while maintaining its cohesion. The approach also enables splitting the swarm in two subgroups in order to direct each simultaneously to a different location.