Mobile Robot Tour Scheduling acting as Data Mule in a Wireless Sensor Network

This article focuses on the utilization of a mobile robot as data mule for collecting and transferring data from a wireless sensor system (WSN). Each static node within the WSN has its data generation rate resulting in an imposed inter-visit duration due to its hardware limitations. The mobile element/robot approaches the nodes, collects their stored data, and transfers these to a depot station. In the adopted scenario, the mobile robot assumes prior knowledge of the nodes' locations and the corresponding trajectories are extracted by solving a combinatorial optimization problem that resembles that of Travelling Salesman Subset-tour Problem (TSSP). The resulting Mobile Element Scheduling (MES) scheme accounts for: the traveling distances between the static nodes, the maximum inter-visit duration for each node to avoid buffer overflow, the visiting/service time at each node and the energy consumption of the mobile robot. The presented simulation studies indicate the effectiveness of the overall optimization concept.