Trail Formation Using Large Swarms of Minimal Robots

Due to the recent advances in robotics, large numbers of robots can be created that exhibit ‘swarm-like’ behavior. These robots, typically small and low-cost with restricted sensing, often exhibit Brownian motion similar to micro-particles. The development of algorithms that create collective behavior that is robust to external pressures has applications in outdoor exploration, search and rescue operations, and nanomedicine. Here, we outline how a swarm of minimal robots, exhibiting only Brownian motion and with limited sensing capabilities, can form trails using mechanisms inspired by diffusion-limited aggregation (DLA). We demonstrate how the trail is robust to obstacles and efficient at finding the closest target. We validate this algorithm both in simulation as well as in reality, using a swarm of up to 100 robots, and highlight the optimum requirements for trail formation.