Robot-assisted maintenance of wireless sensor networks using wireless energy transfer

Wireless sensor networks (WSNs) have proven to be an effective and dynamic paradigm for many applications, including structural health monitoring and tracking systems. However, the supply of energy to the sensors plays a key role in the success of these applications as well as the design and deployment of these networks. Currently, most WSNs are powered by batteries, which must be replaced frequently, increasing maintenance costs and operational complexity. In this paper, we propose a practical framework, called wirelessly energy-charged (WINCH), for battery maintenance; it involves recharging sensor batteries using mobile robots. This framework integrates a routing process in which the cluster heads are selected optimally, as in the low-energy adaptive clustering hierarchy-centralized protocol (LEACH-C), and the robots visit the sites frequently based on need and place themselves in the optimal positions with respect to the selected cluster heads. This approach considerably reduces overhead compared with existing methods. Moreover, we have developed an empirical model of the energy charging rate for sensor nodes. We use this model to compute the amount of energy harvested by each sensor in the proximity of the mobile charger. Simulation experiments for a wide range of design parameters and using several metrics, such as energy consumption, network throughput, and coverage, demonstrate the effectiveness of the proposed framework compared with an existing work.