Research On Fixed-Time Consensus Of Multi-Agent Systems With Disturbances

Multi-agent consensus control is widely used in the fields of formation task of mobile robots and deep space exploration of clustered spacecraft.It refers to the design of consensus protocol based on information exchange to ensure the consensus state of all agents.The main problems include leader following consensus and leaderless consensus.Some achievements have been made,but most of them belong to the category of asymptotic stability.In contrast,the finite-time consensus control can obtain a finite cutoff time,and has stronger anti-interference ability and faster stable speed.But the limiting time depends on the initial conditions.Therefore,the concept of fixed-time stability is proposed,which requires that multi-agent systems can reach agreement in a given finite time under any initial conditions on the basis of finite time stability.And disturbance rejection is also a problem that must be considered in practical research;therefore,this thesis will study the fixed-time consensus problem of multi-agent systems with disturbances.The research work of this thesis is summarized as follows:Firstly,the fixed-time leader-follower consensus and fixed-time leaderless consensus of nonlinear multi-agent systems with disturbances are studied.For the nonlinear multi-agent systems with disturbances in the directed communication topology,a control protocol is proposed to achieve fixed-time leader-follower consensus.Then,aiming at the problem of fixed-time consensus of nonlinear leaderless multi-agent systems with disturbances in general directed communication topology,the corresponding control protocol is proposed,which can make the multi-agent systems achieve fixed-time leaderless consensus.Finally,the simulation results show the effectiveness of the designed control protocol.Secondly,the fixed-time consensus of nonlinear multi-agent systems with disturbances based on dynamic event-triggering control strategy is studied.A distributed dynamic event triggered fixed-time control strategy is proposed,which introduces an auxiliary parameter for each agent to adjust its threshold dynamically.Based on the distributed dynamic event triggering strategy,two distributed adaptive fixed-time consensus tracking control protocols are proposed,which can reduce the update frequency of the controller and reduce the energy consumption while achieving the fixed-time leader-following consensus.In addition,it is proved that the proposed protocol does not exist Zeno behavior.Finally,simulation results show the effectiveness of the designed control protocol.Finally,the fixed-time consensus tracking problem of second-order multi-agent systems with unmatched disturbances in a directed topological network is studied.Based on the fixed time disturbance observer,the system matching disturbance is estimated,and then the non-singular distribution protocol is designed by using the sinusoidal compensation function,which can avoid the singularity of the system and overcome the unmatched disturbance,so that the multi-agent systems can achieve the fixed time consistent tracking.Simulation results show the effectiveness of the designed control protocol.