A Method for Restoring Connectivity of Multi-UAVs Network with Fixed Formation

Multi-UAVs system has received widespread attention for the ability to complete complex tasks. The connectivity is the foundation of cooperation, which can effectively ensure information transmission between UAVs. However, if multi-UAVs system is severely damaged, the network will be decomposed into multiple sub-networks and the connectivity cannot be guaranteed. In order to reconnect sub-networks, most methods restore network connectivity by optimizing positions of UAVs. Although these methods can restore connectivity, the stability of formation has not been considered. This makes the routing of multi-UAVs communication network unstable, leading to a decrease in data transmission efficiency. To solve this problem, we propose a connectivity restoration method with fixed formation for multi-UAVs network. Firstly, we calculate the center point of each sub-network and establish an optimization function for connectivity restoration. Secondly, we obtain the optimal common point based on the optimization function. Thirdly, based on the optimal common point and the center point of each sub-network, we assign an equal velocity to UAVs in the same sub-network to ensure the stability of formation. Finally, UAVs move to the common point based on the obtained velocity until connectivity is restored. The experimental results show that the proposed method can restore network connectivity, and has stable formation.