Research On Several Coordination Problems Of Multi-agent Systems

In recent years,coordination problem of multi-agent systems(MASs)has received significant attention.Distributed strategies,i.e.,using the local information of its own and neighbors to achieve the coordination problem,have dramatic advances.Consensus is one of the fundamental issues in the coordination problem of MASs.In some MASs,there exist one or even more leaders.When there is a leader in the MASs,the consensus problem becomes leader-following consensus problem or tracking problem.When there are multiple leaders in the MASs,the consensus problem becomes containment control problem.In some MASs,which contain some subsystems and an exosystem,designing distributed control laws such that the nominal closed-loop subsystem is exponentially stable and all the subsystems in the network have their outputs track the reference(or reject the disturbance)signals,where the reference input or disturbance signals are generated by the exosystem.This problem in MASs is output regulation problem.Based on switching systems theory and Lyapunov function,consensus,leader-following consensus and cooperative output regulation problems of multi-agent systems are considered in this paper.The main results of this paper are proposed as follow.For MASs with jointly connected topology,leader-following consensus problems by fully distributed protocols are considered in Chapter 2.In each of time subintervals of jointly connected topology,the subgraph is permitted to be disconnected.The union of the switching graphs on the time interval is required to be jointly connected,where the length of jointly connected time interval has the upper and lower bound.The MASs with linear and nonlinear dynamics are considered.The linear and nonlinear distributed adaptive protocols based on common Lyapunov function are respectively designed for the linear and nonlinear cases.Sufficient conditions are given to ensure leader-following consensus of the linear and nonlinear MASs.The consensus problems of identical linear multi-agent systems with aperiodic intermittent communication topology by using the information of second-order neighbors are investigated in Chapter 3.There are some works on accelerating consensus of MASs with continuous communication topology.Different from these works,sufficient conditions are given to obtain the accelerating consensus of MASs with intermittent communication topology by using the information of second-order neighbors.Due to time-delayed communication,the time-delayed and intermittent protocols using the information of second-order neighbors are designed.If the topology is intermittent and connected,and the communication rate is large enough,the consensus is reached by the designed protocols.Then,sufficient conditions are given to obtain the consensus of MASs with intermittent and time-delayed communication topology by using the neighbors' information.The cooperative output regulation of linear MASs under intermittent communication topology is studied in Chapter 4.Different from jointly connected topology,intermittent communication topology is not restricted by the upper bound of the length of switching time interval.Due to the communication is intermittent and all nodes can directly obtain the state information of exosystem is unrealistic,thus we assumed that all nodes can intermittently estimate the exosystem state.It is proved that the state estimations of the exosystem asymptotically converges to the state of exosystem.A technical lemma for the switching output regulation system is obtained to solve cooperative output regulation problem.And some sufficient conditions are separately derived for the cooperative output regulation by distributed statement feedback and output feedback protocols under a directed intermittent communication topology.The cooperative output regulation of linear MASs with time-delay input under intermittent communication topology is addressed in Chapter 5.Each agent also intermittently estimates the state of the exosystem.When state information of each agent and state estimation information of the exosystem is transmitted to input control,there exists time-delays.By means of switching systems theory and Lyapunov-Razumikhin theorem,the linear MASs can reach cooperative output regulation.