Fixed-Time Event-Triggered Cooperative Control Of Multi-Agent Systems

Multi-agent systems consists of multiple agents that can interact with the en-vironment and have the ability to process information autonomously.Compared with traditional single complex agents,multiple bodies work together to improve operational efficiency and reduce consumption.Therefore,they have a wide range of applications in many fields,such as robot collaborative work,UAV formation,and satellite attitude coordination.The main research goal of cooperative control problem in multi-agent systems is to design the controllers such that all agents can achieve an agreement.For consensus control problem,the convergence rate is a very meaningful and important research topic.Most of the existing studies about consensus problem fo-cused on the asymptotic convergence and convergence time was infinite.Moreover,convergence time of the finite-time results depends on the initial conditions.To re-move these restrictions,fixed-time stability was developed,and the convergence time of fixed-time results is bounded by a constant for arbitrary initial condition-s.Herein,we study the fixed-time consensus problem of multi-agent systems via event-triggered control.Combining different control methods with different control objectives not only ensures fast convergence but also reduces the energy consump-tion of communication.This thesis mainly studies the finite/fixed-time problems of multi-agent sys-tems.The adopted control algorithms includes finite-time control.fixed-time con-trol,event-triggered control,and self-triggered control.The main research contents of the thesis include the following aspects:1.For the nonlinear first-order systems.the event-triggered cooperative con-trol and fixed-time self-triggered cooperative control algorithms are given,which proves that all agents can achieve fixed-time consensus.For the event-triggered control,two different triggering conditions are proposed,one requiring continuous communication and one avoiding continuous communication.The proposed self-trigger control not only avoids continuous communication,but also avoids real-time monitoring of its own state.2.To address the average consensus problem of the first-order nonlinear sys-tems under switching topologies,a fixed-time cooperative control algorithm is pro-posed,and the designed Lyapunov function is independent of the network commu-nication topology.Firstly,considering the delayed nonlinear systems with distur-bances,we propose a fixed-time average consensus algorithm.Secondly,in order to reduce the energy consumption and avoid continuous communication,two event-triggered control frameworks are proposed without delay.3.To solve the consensus problem of the first-order delayed systems with un-certain disturbances,two event-triggered consensus control algorithms are designed based on the model reduction method,and it is proved that all agents can achieve fixed-time consensus.For the two triggering mechanisms,one requires continuous communication and one avoids continuous communication.In the case of discon-tinuous communication,more triggering times are required.4.For the second-order disturbed systems,three algorithms(event-triggered control,team-triggered control,and self-triggered control)are designed,and it is proved that the fixed-time consensus is achieved under all the triggering mecha-nisms.For the triggering control,we propose three different triggering conditions,one requires continuous communication(event-triggered),one can avoid a part of continuous communication(team-triggered),and one can completely avoid continu-ous communication(self-triggered).For the self-triggered control,continuous com-munication can be avoided,and real-time monitoring of its own state can be avoided.The team-triggered control,derived by combining the event-triggered control and the self-triggered control,is able to relax the requirement of continuous communi-cation,and thus lowering the energy consumption of communication while ensuring the performance of the system.Besides,there is a tradeoff between the convergence rate,communication cost,and triggering times.5.For the tracking problem of the second-order leader-follower disturbed sys-tems,the event-triggered and self-triggered consensus tracking algorithms are pro-posed,and it is proved that the follower can track the leader in a fixed time or a finite time.For the fixed-time consensus tracking problems,we design an event-triggered control scheme to reduce the frequency of controller updates.For the finite-time consensus tracking problem,we also propose an event-triggered control and a self-triggered control to reduce the energy consumption of communication.For the second-order systems,many models in the actual project have been satisfied and can be widely applied.