Enhancing cooperative transport using negotiation of goal direction

Swarm robotics is a relatively new approach to the coordination of a system composed of a large number of autonomous robots. The coordination among the robots is achieved in a self-organised manner: the collective behaviour of the robots is the result of local interactions among robots, and between the robots and the environment. Each single robot typically has limited sensing, acting and computing abilities. The strength of swarm robotics lies in the properties of robustness, adaptivity and scalability of the group [1]. Foraging is a typical task considered in swarm robotics. It can be decomposed in an exploration subtask followed by a transport subtask. The robotic metaphor consists in the search and retrieval of an object. Therefore, the nest is the metaphorical term for the goal and the prey is synonymous of the object to transport. Examples of applications of foraging are toxic waste cleanup, search and rescue, demining and collection of terrain samples. Central place foraging is a particular type of foraging problem in which robots must gather objects in a central place. Borrowing the terminology from biology, the central place is also called the nest and the objects are called prey. We focus on a specific case in which the transport of a prey requires the combined effort of several robots. This task is called cooperative transport. Several problems need to be solved to perform this task successfully. The coordination of the movement of the robots is one of them. Thi