An Energy-Efficient Routing Algorithm for UAV Formation Based on Time-Aggregated Graph

The limited energy and high mobility of unmanned aerial vehicles(UAVs)lead to drastic topology changes in UAV formation.The existing routing protocols necessitate a large number of messages for route discovery and maintenance,greatly increasing network delay and control overhead.A energyefficient routing method based on the discrete timeaggregated graph(TAG)theory is proposed since UAV formation is a defined time-varying network.The network is characterized using the TAG,which utilizes the prior knowledge in UAV formation.An energyefficient routing algorithm is designed based on TAG,considering the link delay,relative mobility,and residual energy of UAVs.The routing path is determined with global network information before requesting communication.Simulation results demonstrate that the routing method can improve the end-to-end delay,packet delivery ratio,routing control overhead,and residual energy.Consequently,introducing timevarying graphs to design routing algorithms is more effective for UAV formation.

Nonlinear direct data-driven control for UAV formation flight system

This paper proposes the nonlinear direct data-driven control from theoretical analysis and practical engineering,i.e.,unmanned aerial vehicle(UAV)formation flight system.Firstly,from the theoretical point of view,consider one nonlinear closedloop system with a nonlinear plant and nonlinear feed-forward controller simultaneously.To avoid the complex identification process for that nonlinear plant,a nonlinear direct data-driven control strategy is proposed to design that nonlinear feed-forward controller only through the input-output measured data sequence directly,whose detailed explicit forms are model inverse method and approximated analysis method.Secondly,from the practical point of view,after reviewing the UAV formation flight system,nonlinear direct data-driven control is applied in designing the formation controller,so that the followers can track the leader’s desired trajectory during one small time instant only through solving one data fitting problem.Since most natural phenomena have nonlinear properties,the direct method must be the better one.Corresponding system identification and control algorithms are required to be proposed for those nonlinear systems,and the direct nonlinear controller design is the purpose of this paper.

Leader-Follower UAV Formation Model Based on R5DOS-Intersection Model

This paper proposes a formation of multiple unmanned aerial vehicles(UAVs)based on the R5DOS(RCC-5 and orientation direction)intersection model.After improving the R5DOS-intersection model,we evenly arranged 16 UAVs in 16 spatial regions.Compared with those of the rectangular formation model and the grid formation model,the communication costs,time costs,and energy costs of the R5DOS model formation were effectively reduced.At the same time,the operation time of UAV formation was significantly enhanced.The leader-follower method can enhance the robustness of the UAV formation and ensure the integrity of communication during UAV formation operation.Finally,we conducted a simulation experiment on the model and found that the R5DOS model formation was stable and could maintain the desired formation.The randomly generated UAVs could quickly fly to the formation path in a short time,establish formation,and carry out operations.When the leader fails,the follower could travel to the original trajectory of the failed leader in a short time,replace the leader,and continue to communicate and improve the robustness of the formation.To sum up,the UAV formation based on the R5DOS model has the advantages of long operation time,strong endurance,low communication cost,and stable formation,which is of great significance for research on UAV formation.

Eagle-Vision-Based Object Detection Method for UAV Formation in Hazy Weather

Inspired by eagle’s visual system,an eagle-vision-based object detection method for unmanned aerial vehicle(UAV)formation in hazy weather is proposed in this paper.To restore the hazy image,the values of atmospheric light and transmission are estimated on the basis of the signal processing mechanism of ON and OFF channels in eagle’s retina.Local features of the dehazed image are calculated according to the color antagonism mechanism and contrast sensitivity function of eagle’s visual system.A center-surround operation is performed to simulate the response of reception field.The final saliency map is generated by the Random Forest algorithm.Experimental results verify that the proposed method is capable to detect UAVs in hazy image and has superior performance over traditional methods.

The Design of Small Micro-UAV Formation of ＂Sub-mother＂ type

This paper aims to provide a design about a kind of low-cost ＂sub-mother＂ UAV small formation by using the low-cost micro-UAV as the platform. Combined with the current international situation in the UAV formation research, the modeling is based on the distributed control method and the behavior-based strategy. In this paper, some research to a few key issues has been carried out.

An Unmanned Aerial Vehicle Flight Formation for Enhanced Emergency Communication Based on Conformal Antenna Design

Benefiting from the inherent superiorities in flexibility and mobility,the use of unmanned aerial vehicles(UAVs)as flying base stations for wireless coverage has been of significant interest,especially for rescue services.This work concerns the reliable emergency communication based on commercial micro-sized UAVs due to their high availability and low cost.To decrease the weight overloads and to improve the power efficiency,a UAV body conformal and omnidirectional antenna is first presented based on the characteristic mode analysis.To extend the wireless coverage and to improve the communication quality of the UAV network,a UAV flight formation is then proposed and analyzed.In addition,the propagation analyses for the proposed UAV transmitter designs are performed in a realistic hilly canyon region.Simulations and comparisons are presented to demonstrate the effectiveness of the proposed designs in emergency communications and performance enhancement through the UAV flight formation.