Stagnation recovery behaviours for collective robotics

Accomplishing useful tasks with a collection of decentralized mobile robots will require control methods that deal eeectively with a number of unique problems that impede the system's progress. Reactive control architectures can easily cause the problems of stagnation and cyclic behaviour , both characterized by a lack of progress in achieving a task. In this paper we present one possible solution to stagnation recovery, motivated from the study of group transport in ants and demonstrate its use in a box-pushing task. By using stagnation recovery behaviours, which are triggered by a lack of progress in the task-achieving activity of the system, the collective system can monitor its own advancement in a decentralized manner. A set of such behaviours are progressively ordered using timeouts, with each set designed for a speciic recovery strategy. The stagnation recovery behaviours have been tested in simulation with the results to be mapped onto a set of ten autonomous robots presently under construction.