Optimal Performance Analysis Of Networked Control Systems Under Communication Constraint

With the development of integrated automation technology,networked control systems(NCSs)has made great progress.It is a combination of control technology,computer technology and communication technology.In NCSs,the controlled object and the controller are connected by the communication network,and the information is transmitted in the form of packet.In NCSs,a shared network can be used to achieve a flexible architecture that reduces installation and maintenance costs.In NCSs,data is transmitted through the communication network,and the bandwidth and channel capacity of the communication network are limited,which will cause packet loss,delay,bandwidth limitation,quantization,channel noise and other problems,which will change the performance of the NCSs.This paper mainly studies the optimal performance of the NCSs based on the above communication constraints,and analyzes the optimal performance of the system through the decomposition techniques such as factorization,internal and external decomposition,spectral decomposition and Youla parameters.The main contents of this paper are as follows:For single-input-single-output NCSs,we study the tracking performance of NCSs with time-delay and coding and decoding energy constraints.The results show that the effect of non-minimum phase(NMP)zeros,unstable poles and multiple communication constraints such as delay,coding and decoding,and additive white gaussian noise(AWGN)on the optimal performance of the system.Two-degree-of-freedom compensator is superior to single-degree-of-freedom compensator.In addition,it is also found that the tracking performance of NCSs is directly related to encoding-decoding,delay and AWGN.For multi-input and multi-output NCSs,we study the optimal performance of NCSs based on coding and quantization constraints.In the feedback channel of NCSs,the effects of quantization and bandwidth are taken into account,and the effects of noise and encoding and decoding in the two-degree-of-freedom controller are also taken into account.The optimal tracking performance is realized by partial decomposition and spectral decomposition.The results show that the optimal tracking performance depends largely on the given system structure and the characteristics of channel noise and reference signal.In addition,AWGN,quantization,bandwidth and encoding-decoding in the communication channel have certain effects on the system performance.In addition,we study the optimal performance of the multi-input and multi-output NCSs with time-delay and channel noise constraint in the forward network channel,and the encoding-decoding,quantization and packet loss constraint in the feedback network channel.The explicit expression is derived by using the two-degree-of-freedom controller and the parameterization method of Youla.The expression is obtained by using norm method.The results show that the position and direction of NMP zeros and unstable poles are related to the optimal tracking performance.On the other hand,the optimal tracking error depends on constraints such as channel noise,quantization noise,encoding-decoding,delay and packet loss probability.