Mobile Charging And Sensing System Based On RF Energy Harvesting

The traditional WSN nodes usually use batteries as energy source.The operating time of sensor nodes is limited due to the limited battery capacity,thus energy supply has become the biggest bottleneck of WSN.In order to get rid of constraints of energy supply and meet the forwarding needs of sensor data,a mobile charging and sensing system based on RF energy harvesting is propoased in this paper.The rechargeable sensor node harvest and convert the RF energy to power for itself.To get the position of nodes in the 3D space and improve the charging efficiency,the system uses intelligent UAV to carry the power source and data gateway to the designated node location.This paper study the optimal mobile control strategy of energy source in far field wireless charging mode.Based on projection theorem and clustering algorithm,a nested TSP path selection algorithm is proposed.Firstly,a rechargeable sensor node based on RF energy harvesting is designed and implemented.Far filed wireless charging is used for energy transmission.The rechargeable sensor nodes harvest and convert the RF energy from the environment,and convert the RF energy into DC power.Based on lots of experiments,a mathematical model of wireless charging is established.Then,the mobile charging and sensing system based on Intelligent UAV is designed and developed.The UAV is equipped with an energy source,and power for the exhausted sensor node according to the optimal path.The RF transmitter is designed as a energy source which can support 15m charging distance.The system is able to charging nodes deployed in 3D space and suitable for complex environment.Meanwhile,data transmission link from node to cloud server is built by using data gateway to realize real-time display and storage of sensor data.On the basis of the completion of the whole system,it is applied to two practical projects,and a good test result has been obtained.Lastly,a charging scheduling management algorithm for moving energy sources in 3D space is designed.In a certain plane,the UAV follows an intermittent movement mode,and the energy source is radiated down at the same time.On this basis,a circle projection principle is used to reduce the search area,then the position of candidate charging point is obtained by discretization,finally the optimal coordinates of charging point is calculated out using a clustering algorithm.Under the condition of guaranteeing the total charging delay of the system,a set of nested optimal TSP path selection algorithm is constructed to achieve the location of all the optimal charging points in the shortest path of UAV.