Cohesive self-organization of mobile microrobotic swarms

Abstract

Mobile microrobots are envisioned to be useful in a wide range of high-impact applications, many of which requiring 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 enable their selforganization into cohesive clusters. Self-organized microrobotic clusters translate 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 hindered by heterogeneities of individual microrobots. Scalability of cohesive interactions allows formation of larger groups, whose internal spatiotemporal organization undergoes a transition from solid-like ordering to liquid-like behavior with increasing cluster size. Our work elucidates the dynamics of clustering under cohesive interactions, and presents an approach for addressing operation of microrobots as localized teams.

Shape anisotropy-governed locomotion of surface microrollers on vessel-like microtopographies against physiological flows

“…Imaging of the microrollers in the body is another important consideration, though spatiotemporal resolution of the current imaging modalities used in the clinics are not high enough to image individual microrobots (∼8 μm). Swarm manipulation of a large number of microrollers could be beneficial in enhancing medical imaging contrast, and thus enable facile tracking and feedback control for the microrollers (45,46). However, aggregation of microrobots, especially the ones with higher magnetic remanence, is a potential problem for swarm manipulation.…”

Surfactants and rotelles in active chiral fluids

“…Rotating microparticles have been manufactured in various ways (16,24,26,45,46). Adding connectors between particles is possible in principle (47)(48)(49). However, connectors might not even be necessary.…”

Swarming Microdroplets to a Dexterous Micromanipulator

“…[ 38 ] The abilities of these ant aggregations are extensive, mainly because their collective behaviors exhibit both liquid‐like properties (individual units are displaced with respect to their neighbors) and solid‐like properties (individual units perform small fluctuations around their mean internal positions). [ 39,40 ] Viscoelasticity allows the ant aggregation to build structures to negotiate changing environments and tasks. Inspired by viscoelastic fire ant aggregations, we present a strategy to reconfigure ferrofluid droplets into microrobotic swarms with both liquid‐like and solid‐like behaviors by spatiotemporally programming external magnetic fields.…”