Networked Synchronization And Application Of Chaotic Systems Based On Event Trigger Mechanism

With the development of computer and network technology,information encryption and its safe transmission become more and more important.Today,secure communication has become a research hotspot of computer communication,network,microelectronics and other related subjects.Chaotic system has characteristics of randomness,ergodicity,unpredictability and extreme sensitivity to initial conditions,so it is particularly suitable to be a transmission carrier of secure communication.The research of the chaotic synchronization and its realization provide theoretical basis and technical support for chaotic secure communication,therefore,it has aroused researchers' interest in the study of chaotic control and synchronization.There are plenty of research achievements in this regard so far.In this paper,our study mainly focuses on synchronization and application of continuous chaotic dynamic systems and discrete chaotic dynamic systems based on event trigger mechanism.The main work is as follows:Firstly,the research status of chaotic synchronization and chaotic secure communication at home and abroad was introduced,some shortcomings in the present study were analyzed,and the purpose of the research was stated in the thesis.Secondly,the networked synchronization of chaotic Lur'e systems based on event trigger mechanism was studied.It is assumed that quantized sampled measurements are available for the controller of the continuous chaotic systems,and event trigger mechanism with network transmission delay was introduced to decide whether the signal to be quantized for transmission.By viewing the quantized synchronization error as a control signal and constructing appropriate Lyapunov function,we obtained sufficient conditions for the networked synchronization of chaotic Lur'e systems under quantized feedback based on event trigger mechanism.In the end,the effectiveness of the proposed approach in this paper was verified by numerical simulations of Chua circuit chaotic systems.Thirdly,the master-slave synchronization problem of a class of discrete chaotic systems was studied.It is assumed that the controller can only utilize the quantized sampled measurements to achieve the synchronization of discrete chaotic systems.Considering the transmission delay of the system,the event trigger mechanism was introduced to reduce the average transmission frequency of the system and to mitigate the waste of channel bandwidth.By construction of a proper Lyapunov function,a new sufficient condition for networked synchronization of Lipschitz nonlinear discrete chaotic systems under quantized feedback based on event trigger mechanism was obtained,in which quantized synchronization error was used as a feedback control signal.In the end,the effectiveness of the proposed approach was verified by numerical simulations of the Fold discrete chaotic systems.Finally,the applications of chaotic synchronization in secure communications were studied.First of all,chaos masking and multi-shift cipher algorithm were presented,they are two kinds of methods about chaotic secure communication.Then,the applications of continuous chaotic systems and discrete chaotic systems based on event trigger mechanism to secure communication were discussed respectively.In the end,the effectiveness of both communication schemes was verified by two numerical examples.