Building granular structures with elasto-active systems

TL;DR

This paper introduces elasto-active systems combining microbots and elastic beams that can autonomously reshape their environment by aggregating obstacles or carving voids, demonstrating adaptive behavior in granular media.

Contribution

It presents a novel soft active matter system that autonomously reconfigures environments, bridging the gap between rigid robots and natural active systems.

Findings

At low density, the system aggregates obstacles into clusters.

At high density, the system carves voids with predictable sizes.

The behavior is modeled using coagulation theory and force-limited arguments.

Abstract

Natural active systems routinely reshape and reorganize their environments through sustained local interactions. Examples of decentralized collective construction are common in nature, e.g., many insects achieve large-scale constructions through indirect communication. While synthetic realizations of self-organization exist, they typically rely on rigid agents that require some kind of sensors and direct programming to achieve their function. Understanding how soft, deformable active matter navigates and remodels crowded landscapes remains an open challenge. Here we show that connecting rigid microbots to elastic beams yields elasto-active structures that can restructure and adapt to heterogeneous surroundings. We investigate the dynamics of these agents in environments with varying granular densities, rationalizing how they can aggregate or carve the medium through gentle interactions. At low density, the system compacts dispersed obstacles into clusters, a process modeled by a modified Smoluchowski coagulation theory. At high density, our agents carve voids whose size is predicted by a force-limited argument. These results establish a framework for understanding how activity, elasticity, and deformability can influence active navigation and environmental reconfiguration in granular media.