Leader-following Consensus Fault-tolerant Control For Multi-agent Systems Under Complicated Environment

The cooperative control of multi-agent systems has a wide range of applications in wireless sensor networks,aircraft formations,robot control,Internet of Things and other fields.Hence,it has received great attention from scientific and researchers.In practical application,there are unfavorable factors that in the physical environment disturb the dynamic characteristics of the equipment.For example,the aircraft may encounter external disturbances such as wind and rainfall when operating in an outdoor environment,which may cause partial failure of the actuator energy efficiency in the dynamic system of the aircraft,additive disturbance process failure,etc.In addition,the cooperative control of multi-agent systems relies on network communication,and network attacks against multiagent systems emerge in an endless stream,which can lead to the blocking of communication channels between systems and make the cooperative control fail.in order to reduce the energy consumption of the controller and alleviate the limited bandwidth resources,it is of practical significance to design the controller for the agent based on the event-triggered mechanism.At the same time,the intermittent control signal generated by the event-triggered controller effectively reduces the impact of network attacks on the system.Therefore,this paper comprehensively considers the influence of physical environment and network environment on the cooperative control of multi-agent systems,and studies a class of uncertain nonlinear multi-agent systems with mixed faults and network attacks.The leader-following consensus fault-tolerant control problem.The main research work is as follows:(1)The leader-follower consensus control problem is investigated for a class of highorder uncertain nonlinear multi-agent systems based on dynamic event triggering.For uncertain nonlinear terms in the system,a less conservative Lipschitz condition is proposed with unknown Lipschitz gain parameter and the parameter is estimated by using adaptive method.Second,in order to reduce the frequency of controller update,a new dynamic event-triggered control strategy is proposed,and it is proved that the zeno phenomenon does not appear.Based on the Lyapunov stability theory,it is strictly proved that the state of the follower agent tracks the state of the leader asymptotically.(2)A class of uncertain nonlinear multi-agent systems with hybird faults is investigated based on undirection topology.Considering the mixed faults of actuator faults and system process faults at the same time,it increases the difficulty of fault-tolerant controller design.For uncertain nonlinear systems with unmodeled dynamics,we propose a less-conservative consistency strategy,and propose less-conservative Lipschitz conditions for nonlinear terms in the system.Based on the backstepping control method,a fault-tolerant controller is designed for each follower agent.According to the Lyapunov stability theory,it is proved that the proposed fault-tolerant controller can make each follower agent state consistent with the leader state.(3)The leader-following consensus control is studied for a class of uncertain nonlinear stochastic multi-agent systems under denial-of-service attacks.Consider that the communication channel between the agents in the multi-agent system is subject to denialof-service attacks.The channels are blocked and information exchange cannot be performed.According to the attacked topology,a reference signal generator is designed for each agent,so that the agent can obtain the dynamic output signal of the leader.Furthermore,the multi-agent system consensus problem is transformed into a single-agent stochastic system tracking problem.In addition,the system with random disturbances and the failure of the actuators increases the challenges of the controller design.In order to reduce the update frequency of the controller and reduce the energy consumption,an event-triggered fault-tolerant controller is designed.Finally,it is verified by the Lyapunov stability theory that the fault-tolerant controller designed based on the signal generator can ensure the outputs of the followers agent can reacher consenus with the leader’s output.(4)The consensus control problem is investigated for a class of uncertain nonlinear multi-agent systems under denial-of-service attacks and actuator fault.Considering that the event-triggered module inside the system is attacked by denial-of-service attacks.The event trigger mechanism is designed to effectively reduce the number of controller updates and reduce energy consumption.According to the backstepping method,an eventtriggered fault-tolerant controller is designed for each follower agent.The proposed controller switching strategy ensures the stability of the control system and the energy consumption of the system is greatly reduced.It is verified that the output signal of the follower agent can track the output of the leader.A reliable attack detection mechanism is designed,and a controller switching strategy is proposed based on the attack detection mechanism.(5)The leader-following output feedback consensus control problem is studied for a class of nonlinear multi-agent systems under directional fixed topology.Considering the unmeasurable state of the system,a reduced-order dynamic gain filter is designed to reduce the computational complexity of the control system and achieve accurate estimation of the system state.In addition,considering the occurrence of actuator faults,based on the filter and backstepping control method,an event-triggered fault-tolerant controller is designed for each agent.It verifies that the output of each follower agent can achieve consenus of leader.