Cooperative transport in a swarm of aligning active particles

From humans hauling an oversized sofa to ants foraging a large leaf, cooperative transport can be found across the animal kingdom. Yet, achieving cooperative transport by design remains a great challenge for physicists, mechanical engineers, and roboticists. In my talk, I will present the ``transporton'', a new kind of self-propelled particle whose mechanical design gives rise to a novel dynamical response. When subjected to an external force, a transporton aligns and propagates in a direction opposite to the force. This unique force response allows these active particles to spontaneously coordinate transport of much larger objects, alleviating the dependence on a complex circuitry, sensors, or communication. Using both experiments and simulations, we show that the transport propensity of a swarm of transportons is super-linear with group size, a hallmark of cooperation. Finally, we derive an analytical model for the interaction of a transporton with an obstacle, revealing the role of the different parameters at play. Our results both shed light on the mechanical origin of cooperative transport observed in nature, as well as offer engineers a generic design rule for future applications in swarm robotics.