Circle Formation in Multi-robot Systems with Limited Visibility

Pattern Formation in multi-robot systems was proposed in the 1990’s. Since then it has been extensively studied and applied in various ways. To date, the majority of the proposed algorithms that aimed to achieve geometric patterns in the literature have overlooked the visibility limitation in physical robots. In addition, a methodology to reach a complete coordinate agreement has not been adopted by many researchers as a prerequisite towards a successful formation. It should be stressed that such limitation and methodology have a strong effect on the desired pattern approach. In this paper, a decentralized approach for circle formation is highlighted. The main advantage of forming a circle is the flexibility to be generated with different initial distributions. Moreover, circle arrangement can be utilized as a preliminary sub-task for more complex activities in multi-robot systems. To handle the aforementioned realities, this approach is proposed under a realistic robot model – i.e. one that has a short visibility range and performs the task autonomously relying on the information picked by itself, or by the vicinity. In addition, robots do not initially have a pre-defined leader nor unique IDs. Simulation results have validated the robustness and flexibility of the proposed algorithm, where a circular pattern has been successfully constructed in a self-organized manner.