Research On Wireless Ultraviolet Collaborative UAV Formation Communication Topology Optimization

The Unmanned Aerial Vehicle(UAV)is widely used in various fields because of its low cost,strong flexibility and easy operation.However,due to the limited computing capability of a single UAV,the use of swarm formation can effectively expand the reconnaissance search range of UAV and improve the success rate of mission completion.The foundation of UAV formation cooperation is to establish a reliable and stable communication network.Wireless ultraviolet(UV)communication has the advantages of non-line-of sight(NLOS)and secret security,which can provide effective guarantee for information exchange in complex environment between UAVs such as strong electromagnetic interference.To reduce the communication complexity of the UAV formation and balance the energy consumption of nodes,it is important to optimize the communication network topology of UAV formation.Therefore,the ultraviolet communication technology is applied to UAV formation flight in this thesis.On the basis of establishing the ultraviolet communication link model and energy consumption model,the formation communication topology optimization based on optimally rigid graph is studied.The main work are as follows:(1)Aiming at the problems of high communication complexity and low fault-tolerant of the network after UAV formation assembly,the algorithms for generating optimally rigid formation in two-dimensional and three-dimensional space are proposed in this thesis.The path loss of ultraviolet communication is set as the link weight,and the reliable links with lower value are selected firstly to construct the optimally rigid topology.A neighbor discovery method based on information frame is designed in three-dimensional space.The ultraviolet hemispherical LED array is used to help the UAV to find its neighbor nodes,the optimally rigid subgraph is generated among UAV and its neighbor nodes firstly,and then the global optimally rigid formation graph is obtained by deleting links.The performance of the proposed algorithm is compared with other algorithms in the communication complexity,average node degree and average communication radius.The results show that the proposed algorithm improving the fault-tolerant performance of network while reducing the complexity of formation communication.(2)In view of the large number of nodes in UAV formation,a clustering topology management is adopted to simplify the network structure.Considering the unbalanced of energy consumption during the data transmission,the formation clustering routing algorithm based on the optimally rigid graph is studied under the cooperation of ultraviolet communication.Based on the energy consumption model of wireless ultraviolet communication between UAVs,the selection of cluster heads and the communication between clusters in the process of clustering are improved simultaneously.The weight functions of node residual energy and link reliability are introduced to select the cluster heads,and the topology optimization is carried out by generating optimally rigid graph among the cluster heads.The simulation results show that the connectivity of the inter-clusters is improved and the phenomenon of the node death is delayed in the network,the death time of 1%and 50%nodes in the network is delayed by 25.2%and 21.3%respectively compared with LEACH algorithm.In summary,the wireless ultraviolet is applied in UAV formation in this issue to ensure the secret and reliability of inter-UAVs communication.The topology optimization algorithm of UAV formation communication network based on optimally rigid graph is studied.The simulation results show that the topology constructed by this algorithm can maintain the formation with lower communication complexity,thus reducing the energy consumption of UAV network and prolong the survival time of UAV formation.