Research On Security Control Strategies For Complex Network Systems Under Communication Constraints

In recent years,networked control systems(NCSs)have been widely applied in various industries.Differing from general control systems,the components of NCSs are connected through networks to achieve information sharing,and simplify the installation process,so that the whole system maintenance becomes more convenient.With the continuous expansion of application fields,the complexity of control tasks and controlled objects in NCSs continues to rise,and complicated NCSs(C-NCSs)containing multiple subsystems have emerged.Although C-NCSs have been successfully applied to modeling many practical systems,there are still many technical challenges in the specific implementation.The primary challenge is how to effectively ensure system performance under limited communication resources.The existed researches mainly focus on event triggering mechanisms(ETMs)and communication protocols to address communication resource constraints.Following ETMs,only the signals that satisfying the event triggering conditions can be released into the communication network.However,how to select and design ETMs that are suitable for specific application scenarios remains a hot and difficult topic in current research.The communication protocol is aimed at avoiding data conflicts caused by bandwidth limitations through reasonable scheduling of nodes and has received considerable research attention.In addition,how to effectively resist cyber attacks is another key challenge in the practical application process of C-NCSs,as cyber attacks may lead to system performance degradation and even system paralysis.The main types of cyber attacks include deception attacks and denial of service(DoS)attacks.Although these two types of cyber attacks have been studied to some extent,considering the structural characteristics of C-NCSs,attacks on them exhibit asynchronous characteristics.Therefore,the security control problem of C-NCSs under asynchronous cyber attacks still needs further research.Based on the above analysis,this article will conduct research on security control strategies for C-NCSs under communication constraints from the following three aspects.Firstly,the distributed event triggered synchronization control problem of complex networks(CNs)under asynchronous nonperiodic DoS attacks is studied.In order to reduce the pressure on network bandwidth,a distributed ETM is adopted at each coupling node to determine whether to send signals to the communication network.Assuming that the communication network contains multiple transmission channels,and DoS attacks will independently harm each channel,then sufficient conditions to ensure system secure synchronization are analyzed.Secondly,in continuous time large-scale networked systems,a centralized ETM based on software defined networking is designed.By comprehensively consider the impact of asynchronous deception attacks,the security control problem of large-scale networked systems is studied,and sufficient conditions for achieving consistent and ultimately bounded stability of the system are analyzed.Finally,considering the coupling effect and the impact of cyber attacks,the round robin protocol is adopted to avoid data conflicts caused by limited communication resources.Focusing on asynchronous deception attacks occurring on the communication network between controllers and actuators,the synchronous control methods for discrete-time CNs is studied.And the effectiveness of the proposed method is demonstrated through simulation experiments.