Research On Consensus Tracking Control Of Multi-agent Systems

In recent years,researches on multi-agent systems have become a hot topic of scientific research.Multi-agent systems have been widely applied in many different fields,such as biology,robotics,military,traffic control system because of their interactive,autonomous and distributed features.The analysis of consensus problems is a key point of cooperation control in multi-agent systems.The consensus problems can be classified into two aspects as leaderless case and leader-follower case,and the leader-follower structure is widely used in many practical systems.Therefore,researches on consensus tracking control for multi-agent systems have special significance,so this thesis mainly discusses the consensus tracking problem of multi-agent systems.The main contents are as follows:The consensus tracking problem of multi-agent systems with disturbances is studied under the assumption that all the states,such as the position and velocity of all agents in the system,are all measurable.According to the high order sliding mode advantages,such as robustness,insensitivity to disturbance and chattering suppression,a control algorithm based on high-order sliding mode control theory is proposed in this thesis.The proposed algorithm is proved by Lyapunov stability theory,and the effectiveness is shown by a simulation example.Based on the fact that the speed information of an agent is uneasy to access,the consensus tracking problem of multi-agent systems with disturbances under the assumption that the follower agents' states are unknown is further investigated.In this thesis,a sliding mode observer is designed based on Super-Twisting second-order sliding mode algorithm to estimate the states of follower agents.Moreover,the Super-Twisting second-order sliding mode protocol is designed to suppress the disturbance and realize the consensus tracking of the multi-agent systems.Based on finite-time stability theory,it is proved that the observer can effectively estimate the variables of the follower agents in finite time.Moreover,the system can achieve consensus tracking with the control algorithm,which has been proved based on Lyapunov stability theory.Finally the simulation example is given to illustrate the feasibility of the observer and control protocol.The consensus tracking problem of nonlinear multi-agent systems is also considered.Because the event-triggered control strategy has the advantages of saving energy and reducing energy consumption compared with continuous control and communication,a consensus tracking control algorithm based on the event-triggered control strategy is designed in this thesis.Based on Inequality and Comparison Principle,it is proved that the interval between the two events in the system has a positive lower bound,so the Zeno behavior is excluded.The correctness of the proposed algorithm based on the event-triggered control strategy is proved by Lyapunov stability theory,and the effectiveness is shown by a simulation example.