Collective Retrieval by Autonomous Robots

The paper presents an experiment of a collective pulling of one object by three Lego R ©robots. The robots use two parameters to orient their pulling force: 1. the direction to the nest 2. the local perception of the movement of the prey. Three behavior-based programs have been experimented to study the impact of each parameter. Although a solution can be found by using random trials in the direction of the nest, we observe that a better coordination ensues from a minimal number of agents around the prey. We show that an adequate number emerges from the use of a stigmergic communication through the prey.