Collective behavior of self-steering active particles with velocity alignment and visual perception

Abstract

The formation and dynamics of swarms is wide spread in living systems, from bacterial bio-films to schools of fish and flocks of birds. We study this emergent collective behavior in a model of active Brownian particles with visual-perception-induced steering and alignment interactions through agent-based simulations. The dynamics, shape, and internal structure of the emergent aggregates, clusters, and swarms of these intelligent active Brownian particles (iABPs) is determined by the maneuverabilities $Ω_v$ and $Ω_a$, quantifying the steering based on the visual signal and polar alignment, respectively, the propulsion velocity, characterized by the P{é}clet number $Pe$, the vision angle $θ$, and the orientational noise. Various non-equilibrium dynamical aggregates -- like motile worm-like swarms and millings, and close-packed or dispersed clusters -- are obtained. Small vision angles imply the formation of small clusters, while large vision angles lead to more complex clusters. In particular, a strong polar-alignment maneuverability $Ω_a$ favors elongated worm-like swarms, which display super-diffusive motion over a much longer time range than individual ABPs, whereas a strong vision-based maneuverability $Ω_v$ favors compact, nearly immobile aggregates. Swarm trajectories show long persistent directed motion, interrupted by sharp turns. Milling rings, where a worm-like swarm bites its own tail, emerge for an intermediate regime of $Pe$ and vision angles. Our results offer new insights into the behavior of animal swarms, and provide design criteria for swarming microbots.