Reconfigurable robust microrobot collectives with large force output enabled by gradient magnetic fields

Robot collectives offer a promising solution for complex assignments that are nearly impossible for individual robots to execute. In microscopic scenarios, organizing microrobot collectives is now governed by agent-agent physical interactions. However, the existing methods are insufficient to produce robust connections and fail to tolerate harsh environments. We propose a strategy to efficiently program microrobots into reconfigurable robust collectives to operate in various dynamic environments. Magnetic collectives are produced to achieve reconfigurable pattern transformation with considerable structural enhancement via well-designed gradient magnetic fields. The strong gradient magnetic field-induced connections among individual microrobots enable a record-breaking 700-fold output force enhancement, and 0.2-gram microrobot collectives generate Newton-level output forces. The proposed reconfigurable microrobot collectives provide a stable and promising approach to executing droplet, fluid, and solid manipulations via powerful output forces. These results may have implications for further understanding of self-assembly, particle systems, microrobot collectives, smart dust, and related microscopic multiagent behaviors.