Event-triggered Synchronization Of Networked Control Systems And Its Applications

With the integration of control theory,network communication theory and computer technology,the networked control systems(NCSs)have been a great development,and have been widely applied in many fields,including the traffic control,aerospace engineering,smart city and so on.The deployment of components of the NCSs makes the designed protocol to achieve the cooperative goals by communication with their neighbors.The smooth performance should be ensured by communication channels.However,the network bandwidth,the cost of communication and the resource of nodes are limited when the CNSs work in practical environment.More reasonable control protocols should be designed to ensure that the cooperative tasks can be successfully accomplished.Event-triggered control(ETC)strategy has the advantages in reducing the communication frequency,salving the resource and relieving the data transmission pressure of the CNSs.The event-triggered control method belongs to the field of hybrid control method,and the analytical tools for such method are far from being completed.In addition,the case of transmission delay,packet loss and disorder may occur during the process of information interaction among nodes in practical environment,which leads to many challenges in the design of distributed event-triggering protocol and the synchronization analysis of multi-agent systems.Hence,it is of both academic and realistic importance or interest to study the design of the event-triggered control scheme and its theoretical analysis.This paper devotes to developing the event-trigged control theory and proposing some outstanding triggering control protocols for NCSs.The main contents of this dissertation are summarized as follows:(1)The impulsive synchronization of a class of leader-following multi-agent systems(MASs)under a distributed event-triggered communication law is discussed.The synchronization conditions for the MASs under the event-triggered impulsive control scheme are established by using Lyapunov stability theory and inequality technique.A distributed self-triggered impulsive control strategy is designed to avoid the continuous communication among agents,which only depends on the sampling information at the triggering instants.Both the triggering conditions can guarantee that the Zenobehavior does not appear in the MASs.In addition,the synchronization framework of the leader-following MASs under the event/self-triggered impulsive control is presented,which realizes the asynchronous and aperiodic control for the agent networks.(2)A dynamic distributed self-triggered impulsive control strategy for MASs is designed by introducing an internal dynamic variable into the static distributed selftriggered condition.The Zeno-behavior is excluded in the MASs under the dynamic distributed self-triggered impulsive control.Also,it can be proved that the sampling frequency of the dynamic distributed self-triggered rule is lower than the static case.This means that the dynamic distributed self-triggered rule has a greater advantage in economizing the resource of MASs over the static triggering law.Furthermore,the impulsive gain characterized by a normal distribution is discussed.The constant impulsive gain is replaced by random values obeying a normal distribution,which reduces the conservativeness of the impulsive systems and extends the application of this method.(3)The protocol design about the fully distributed event-triggered control for MASs is considered.Fist,the synchronization problem of MASs under a dynamic distributed event-triggered scheme is studied,where the communication topology is a connection simple graph.The synchronization conditions of MASs are established by using an estimation of the algebraic connectivity of the graph,in which the estimation value only depends on the number of nodes in the networks.In addition,the fully distributed event-based control for a generalized linear MASs with input saturation is investigated,in which the communication topology is a weigthed undirected graph.Several triggering laws and control protocols are designed,and several bounded synchronization criteria for MASs have been obtained.All do not rely on the node number,the Laplacian matrix of the communication topology and its eigenvalues.This means that the designed eventtriggered strategies will still be valid and do not need to be redesigned if the network graph changes(e.g.the topology switching and the nodes added/removed).It expands the applicable scope of the presented event-triggered synchronization algorithm.(4)The synchronization for a class of master-slave nonlinear systems is investigated.First,an event-triggered impulsive control scheme for master-slave Chua's Circuit is designed to realize the state synchronization,and the synchronization criteria are obtained.Furthermore,a periodic self-triggered impulsive cotrol strategy is proposed for the chaos synchronization of master-slave neural networks(NNs).The periodical self-triggered impulsive avoids the continuous communication between the master system and the slave system.It also has the feature of easy implementation.This method is utilized into the field of image protection,where an image encryption framework based on the chaos synchronization of the driven-response neural network with the period self-triggered impulsive control is presented.This image encryption algorithm(IEA)satisfies the encryption performance with higher security since the key space is larger than the traditional chaos image protection algorithm.