Research On Charging Strategy Of Wireless Rechargeable Sensor Networks In Coal Mine

Coal mines enviroment is very bad,continuous and stable monitoring is a necessary requirement to ensure safe production of mines.Wireless sensor networks(WSNs)deployed in coal mines can provide safer and more reliable working conditions for coal mining workers,but the energy limitation of sensor nodes has hindered the development of traditional WSNs,especially in mine roadways where sensor nodes are required to continue to work.In order to solve this problem,in the past few years,wireless rechargeable sensor networks(WRSNs)have been proposed and widely studied.In theory,WRSNs can effectively solve the node energy supply problem.In WRSNs,in order to ensure that sensor nodes continue to work stably,the most core issues is how to plan the charging strategy.Based on the special environment of mine roadway,this paper applies wireless charging technology to traditional WSNs in underground mines,and analyzes the problems of static charging deployment and mobile charging strategy,and studies the WRSNs charging strategy for coal mines.Firstly,this paper studies and analyzes the static deployment strategy of charging WRSNs in mine roadway by static charging device,and proposes the deploying algorithm based on grid division for wireless charging devices in coal mine.The static deployment problem of the charging device is transformed into the charging coverage problem,and the optimal charging coverage model is established.The proposed algorithm utilizes the idea of grid division to select the optimal deployment location of the charging device by continuously scanning the grid,and minimizes the number of charging devices required to be deployed while meeting the energy requirements of all sensor nodes in mine roadway.Then,through a lot of simulation experiments,the effects of different grid sizes and charging radii on the charging coverage performance and the influence of different charging radii on the number of charging devices are analyzed.Then,this paper studies and analyzes the mobile charging strategy of charging WRSNs in mine roadway by using several charging devices that can move along the roadway track,and proposes the completely feasible and nodes-grouped scheduling algorithm.Aiming at the limited moving path of charging devices,the target problem is transformed into the charging time allocation problem limited by the charging of the roadway.The boundary conditions that can guarantee the charging strategy completely feasible are derived,and the problem model is established.The proposed algorithm divides the whole roadway network into several sub-networks.The charging device provides energy to the sub-network in a cyclical manner to meet the energy requirements of the entire network.At the same time,the node grouping mechanism is used to expand the sub-network size.Then,a lot of simulation experiments were carried out to verify and compare the performance of the proposed algorithm,and the influence of various parameters on the charging strategy are further analyzed.