Formation Control For Multi-UAVs System With Random Time-delay

With the development of science and technology,Unmanned Aerial Vehicle(UAV)has gradually penetrated into the civilian field from the military field and into the public users from scientific researchers and technicians,playing an increasingly important role in all aspects of modern society.Compared with a single UAV operation,multi-UAVs formation system has higher efficiency,stronger stability and robustness,and is more suitable for high-intensity and complex tasks.Although multi-UAVs formation has the above advantages,the application of the formation is still limited at present.UAV formation application is limited because the stability of the system are susceptible to the influence of various factors,such as: the air vortex caused by other UAV in the crew;the time-delay in the communication networks when UAVs exchange their information between each other and the input saturation of the UAV's own implementation device.Therefore,this paper conducts in-depth research on the control methods of UAV formation under the influence of the above conditions.The main research contents and results are as follows:Firstly,this paper studies a multi-UAVs formation control method with energy constraint.Inspired by the fact that birds formation can save energy to achieve long-distance migration,this paper uses the flight mechanism of the bird formation and the mapping relationship between the bird swarm and multi-UAVs formation summarized by literature,considers that the UAV communicates in an ideal state,that is,without the influence of time-delay and considers the air vortex between the UAVs,aims at minimizing energy consumption.By introducting the quadratic optimal control,a multi-UAVs formation control method with energy constraint is designed,which realized the formation control of multi-UAVs with minimum energy consumption.Secondly,this paper studies a multi-UAVs formation control method with random communication time-delay.In the formation flight process of UAV,there is information interaction between UAVs,and in the process of information interaction,the transmission delay of information is inevitable.Considering the randomness of the information transmission delay,Bernoulli random distribution is used to describe the occurrence of delay,and based on the consensus theory,a multi-UAVs formation control method is designed.Lyapunov-Krasovskii functional is established,and based on the stability theory of Lyapunov,the stability conditions related to the random time delay of multi-UAVs formation control are given in the form of Linear Matrix Inequality(LMI),and the formation of multiple fixed-wing UAVs with random time-delay in mean square sense is finally realized.Thirdly,this paper studies a multi-UAVs formation control method with random time-delay under input saturation constraint.In the process of UAV formation flight,the UAVs in accordance with the instructions to make complex movements,the required amount of control may be more than actuators can provide maximum output,namely actuator saturation phenomenon,it will reduce the flight performance of UAV,serious when even lead to UAV is out of control.Therefore,it is of practical significance to consider the input saturation limits in the formation process.Meanwhile,the existence of time-delay will also lead to system performance degradation.Based on these,a multi-UAVs formation control method with random delays under input saturation constraints is proposed.Lyapunov theory is used to analyze the asymptotic stability of the closed-loop system and the necessary conditions for the asymptotic stability of the multi UAV system are given,and the formation of multiple fixed-wing UAVs with random time-delay under input saturation constraint in mean square sense is finally realized.