Uniform Grid Formation by Asynchronous Fat Robots

In this paper, we introduce a distributed algorithm for the formation of a grid pattern by multiple homogeneous, autonomous, disc-shaped robots (also referred to as fat robots). The robots organize themselves to form a grid (not given in prior) which is required for covering, safeguarding or supervising a geographical region by the robots. The operation of the robots is based on execution cycles of the phases ‘wait–look–compute–move’. In the ‘wait’ phase, the robots are inactive or dormant; in the ‘look’ phase, they observe within their visibility range; in the ‘compute’ phase, the robots decide a destination to move to; and finally, they advance to their decided target point in the ‘move’ phase. Eventually, the robots distribute themselves to create a grid. They are oblivious, i.e. the robots cannot recollect any past action or looked data from a previous cycle, and there is no interaction among these robots by message passing. They are anonymous, identical and have unlimited visibility. Though the robots are see-through or transparent, they are physical obstruction for the others. The algorithm proposed here also ensures the prevention of deadlock and collision among the robots.