Yigit Berk, Alapan Yunus, Sitti Metin
Physical Intelligence Department, Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany.
Soft Matter. 2020 Feb 26;16(8):1996-2004. doi: 10.1039/c9sm01284b.
Mobile microrobots are envisioned to be useful in a wide range of high-impact applications, many of which require cohesive group formation to maintain self-bounded swarms in the absence of confining boundaries. Cohesive group formation relies on a balance between attractive and repulsive interactions between agents. We found that a balance of magnetic dipolar attraction and multipolar repulsion between self-assembled particle chain microrobots enables their self-organization into cohesive clusters. Self-organized microrobotic clusters move above a solid substrate via a hydrodynamic self-propulsion mechanism. Cluster velocity increases with cluster size, resulting from collective hydrodynamic effects. Clustering is promoted by the strength of cohesive interactions and is hindered by the heterogeneities of individual microrobots. The scalability of cohesive interactions allows the formation of larger groups, whose internal spatiotemporal organization undergoes a transition from solid-like ordering to a liquid-like behavior with increasing cluster size. Our work elucidates the dynamics of clustering under cohesive interactions, and presents an approach for addressing the operation of microrobots as localized collectives.
移动微型机器人有望在广泛的高影响力应用中发挥作用，其中许多应用需要形成凝聚性群体，以便在没有限制边界的情况下维持自我约束的群体。凝聚性群体的形成依赖于个体之间吸引和排斥相互作用的平衡。我们发现，自组装粒子链微型机器人之间的磁偶极吸引和多极排斥的平衡使其能够自组织成凝聚性簇。自组织的微型机器人簇通过流体动力自推进机制在固体基质上方移动。簇速度随着簇大小的增加而增加，这是由集体流体动力效应导致的。凝聚相互作用的强度促进聚类，而个体微型机器人的异质性则阻碍聚类。凝聚相互作用的可扩展性允许形成更大的群体，随着簇大小的增加，其内部时空组织经历从类似固体的有序到类似液体行为的转变。我们的工作阐明了凝聚相互作用下聚类的动力学，并提出了一种将微型机器人作为局部集体进行操作的方法。
