Research On The Regulation Performance Of Networked Time-delay Systems Under Communication Constraints

In recent years,with the development of computer technology,the control systems tend to be more and more networked and intelligent,and are widely used in smart grid,environmental monitoring,aerospace and other military and civilian fields.Compared with traditional control systems,information transfer among controllers,sensors and controlled objects of networked systems greatly reduces the spatial constraints due to the use of wireless communication technology.Meanwhile,it also has the advantages of low cost,simple installation and maintenance,light weight,and low power consumption.However,the communication network is not a reliable communication medium,and the ensuing problems such as network delay,packet dropouts,bandwidth limitation,quantization,channel noise,and external interference signals can make the communication between systems limited and thus affect the system performance.In addition,the widespread use of time-delay systems in reality also makes the internal time-delay an important parameter to study.Therefore,in this paper,the regulation performance of the controlled system is studied by using frequency domain methods with the tools of coprime factorization,spectral decomposition,H₂ norm theory and Youla parameterization for these network constraints.The research work is as follows:The problem of optimal regulation of networked time-delay systems is studied,taking into account the presence of packet dropouts,codecs and channel noise in the communication channel.The exact expression of the optimal regulation performance is obtained by means of the Youla parameterization of the controller and the spectral decomposition.The results indicate that the regulation performance of the controlled object is influenced by its inherent characteristics（unstable poles and non-minimum phase zeros）.In addition,packet dropouts and channel noise degrade the optimal regulation performance of the system,while codec improves the regulation performance to some extent.The optimal regulation problem of a multi-input multi-output networked time-delay systems with a random interference signal is investigated under the communication bandwidth constraint.The regulation performance is measured according to the output response of the controlled object after being affected by the interference signal,and the optimal regulation performance index is obtained by the design of the controller.The results indicate that the optimal regulation performance is determined by the location and direction of the inherent characteristics of the controlled object as well as the internal time delay,and is also influenced by the communication bandwidth and the interference signal.Considering the limited network resources,the optimal regulation problem of discrete time-delay systems based on input energy constraints and quantization is studied.The explicit expression of the optimal regulation performance is obtained by using inner-outer factorization,partial factorization and two-degree-of-freedom controller.The results indicate that the optimal regulation performance is related to the inherent characteristics of the system,and reveal that the quantization noise will deteriorate the regulation performance of the system to a certain extent with the continuous increase of the quantization interval.In addition,the greater the input signal energy,the better the regulation performance of the controlled system.