Coordinating Robots for Connectivity in Wireless Sensor Networks

Mobile robots improve scalability and performance of wireless sensor networks. Protocols for many services including data collection, localization, topology control and security in wireless sensor networks include mobile robots. Using a single robot limits the scalability and performance and multiple robots are used as a result. When multiple robots are deployed, it is desirable to have the robots connected to provide improved services. However, coordinating the robots optimally to achieve connectivity among them is not trivial. We use computational geometry techniques to achieve connectivity. We use the concept of Frechet distance between curves to synchronize the robots for connectivity. We extend the idea of Frechet distance to multiple curves where each curve is the path of a robot. We analyze the proposed idea theoretically and show that the theory can not be applied directly due to limitations on robot speed and speed changes. Therefore, we propose a practical approach where maximum robot speed is bounded and speed changes is limited. Simulations show that the connectivity among the robots is maintained when the robots follow the movement pattern based on the Frechet distance between the paths of consecutive robots.