Limit Performance Analysis Of Networked Control Systems Based On Communication Constraints

For traditional control systems,the performance analysis has been relatively mature and it is well known that the optimal tracking performance of networked control systems(NCSs) is influenced by the non-minimum phase zeros and unstable poles of the given plant and the characters of the reference signal.However,compared with the traditional control systems,the difference between of it is the intervention of the communication network.Therefore,the signals in the process of transmission will inevitably exist packet dropouts,network-induced delay,bandwidth limitation,communication channel input power constraints and the impact of disturbance signal.These factors are called the communication constraints,that changed the performance limit of NCSs,thus the analysis will also become more complicated.This paper applied the spectral technique,partial fraction technique and inner-outer technique and then based on considering under the communication constraints,deeply studied the performance limits of NCSs.The main research content is as follows:For the multiple-input multiple-output networked control systems,considering the network-induced delay and data dropouts exist in the communication channel,and then tracking the step signal to investigate the optimal tracking performance limitation.Applying the two-parameter controller structure to get the mathematical expression of optimal performance,the obtained results show that the nonminimum phase zeros and unstable poles of the given plant and their directions can influence the performance,in addition,the network-induced delay and data dropouts can also inevitably effect the performance.Considering the encoder,decoder exist in the communication,studied the optimal tracking performance of multiple-input multiple-output(MIMO) linear time-invariant discrete-time system.Applied the one-parameter controller structure,the technology of spectral decomposition and all-pass decomposition obtained the expression of optimal tracking performance.The obtained result show that theoptimal performance is influenced by the directions and locations of the non-minimum phase zeros and unstable poles of the given plant.In addition to that,the characters of the reference signal,coder,decoder,additive white Gaussian noise(AWGN) of the communication channel are also closely influenced by the optimal tracking performance.Bandwidth limitation is inevitably exist in the communication channel in the practical application.Motivated from this,we investigated the relationship between the bandwidth constraint is necessary.Considering the one-parameter and two parameter controller,respectively.Applied the new performance indicator and using the technology of spectral decomposition and all-pass decomposition studied the problem of optimal tracking performance of multiple-input multiple-output(MIMO)linear time-invariant continuous system.The obtained results show that the non-minimum phase zeros,unstable poles,as well as the locations and directions of them can influence the optimal tracking performance,furthermore,the characters of input signal,modified factor,the bandwidth and channel noise constraints are also closely related to the optimal performance.For NCSs,sometimes the quantization is essential in the signal transmission.The quantization can directly affect the performance of networked control systems,even can cause systems instability.Therefore,it is important to study the relationship between the quantizer and the optimal tracking performance.For multiple-input multiple-output(MIMO) linear time-invariant discrete-time system,consider the uniform quantizer exist in the forward path,applied the technology of spectral decomposition,inner-outer and all-pass decomposition,consider whether the input power constraint is exist and tracking a random signal to study the issue of optimal tracking performance.