Leader-following Consensus Control Problems Of Nonlinear Multi-agent Systems Via Impulsive Saturation Protocols

Distributed collaborative control as one of the most effective control technology in engineering applications,compared with centralized control,it can achieve control objectives only through local communication without the need of central control.Based on strong robustness,scalability,efficiency and other significant advantages,the distributed collaborative control problems of multi-agent systems have been paid more attention by many scholars at home and abroad,and widely used in aerospace technology,smart grid,network security and other important fields.Meanwhile,the consensus problem of multiagent systems is referred to as the basic problem of collaborative control,which has also been a major research topic.In the actual system,because of the saturation characteristics and fault phenomena of the system actuator,the unknown nonlinear characteristics caused by the system itself or external disturbance,and the delayed phenomenon that occurs in the process of information transmission,the multi-agent systems with factors such as saturation input,unknown input,unknown nonlinearity,and time delay are more valuable for application.Impulsive control technology equipped with the non-continuous communication has been widely used in multi-agent systems due to the limited communication resources of the actual system.This paper mainly studies the leader-following consensus problems from the nonlinear characteristics of known and unknown systems,undelayed and delayed impulsive saturation control.The main contents of this thesis are as follows:(1)The leader-following consensus problem of nonlinear multi-agent systems based on impulsive saturation protocol and grouping mechanism is studied.Aiming at multiple leaders and followers in different initial states,a set of grouping mechanism based on the similarity between followers and leaders is proposed to solve the problem of follower allocation,where the symbol functions is introduced to accurately determine the number of followers in each subgroup(subsystem).Further,for each different subsystem,combined with impulsive control technology and convex analysis technology,different impulsive saturation control algorithms are designed to deal with the problem of limited communication resources and saturation of system actuators.At the same time,the problem that different subgroups cannot communicate is addressed since each agent in this algorithm can interact with any subgroup agent information.With the help of Lyapunov stability theory,the suitable Lyapunov auxiliary function is constructed to obtain the sufficient conditions of subsystem stability,the leader-following consensus problem of each subsystem among nonlinear multi-agent systems and the different leader-following consensus problem of different subsystem are solved respectively.Finally,one simulation is presented to verify the feasibility of the theoretical result.(2)The adaptive fault-tolerant leader-following consensus problem for multi-agent systems with nonlinear dynamics via delayed impulsive saturation protocol is analysed.In view of the unknown degree of actuator failure in a single agent system,combined with fault-tolerant control technology and adaptive method,a distributed adaptive faulttolerant control algorithm based on local communication between agent and its neighbors is designed through introducing the concept of projection operator,and the problem of large error caused by inaccurate estimation of unknown parameters is solved.Further,combined with impulsive control technology,convex analysis technology,Lyapunov stability theory,a delayed impulsive control algorithm with saturation constraint is designed.With introducing state error function between follower and leader,the corresponding Lyapunov auxiliary function is constructed to obtain the sufficient conditions for system stability,and the leader-following consensus problem of multi-agent systems with unknown actuator fault and delayed information transmission is addressed.Finally,one simulation is presented to verify the effectiveness of the theoretical result.(3)The adaptive fuzzy leader-following consensus problem of multi-agent systems with nonlinear dynamics via impulsive saturation control is discussed.Under the existence of unknown nonlinear multi-agent systems,combined with the concept of fuzzy logic system and adaptive control technology,the adaptive fuzzy control based on local communication between agent and its neighbors is designed to approach the unknown nonlinear item of system model by using specific mathematical model,and the problem that multi-agent systems contain unknown nonlinearity is solved.Further,by means of the concept of convex function and saturation function,the problem of actuator saturation in multi-agent systems is solved.On this basis,combined with impulsive control technology and Lyapunov stability theory,one impulsive saturation control protocol is designed to deal with the leader-following consensus problem of multi-agent systems with unknown nonlinearity and actuator saturation,whose theoretical proof is given.Finally,the validity of the theoretical result is verified by one numerical simulation.