Spiraling together: Inducing aggregation in simulated microscopic robots through communication using excitable dynamics

Recent progress in microfabrication microrobotics has enabled the designrealization of functional microscopic robots with on board computation, yet limits on computational power and communication bandwidth constrain their individual capabilities. A key challenge is to determine how coordinated, large-scale behavior can arise from interactions among such simple agents. Here, we demonstrate that local, non-specific communication coupled with internal excitable dynamics can robustly organize aggregation and transport behaviors. Using HOOMD-Blue simulations, we model microscopic robots as nearly hard discs capable of emitting and receiving diffusive signals governed by excitable dynamics. By coupling excited states to self-propulsion such that robots move toward the source of their excitation, we induce aggregation. Under appropriate conditions, this also gives rise to spiral topological defects, which stabilize aggregates and act as organizing centers for desired complex collective behaviors, such as pattern formation and directed transport. We identify the internal and environmental parameters most conducive to defect formation, establishing guiding principles for implementing emergent organization in physical microrobotic systems.