The New Stability And Stabilization Of Nonlinear Networked Control Systems With Time Delay

In the traditional closed-loop control system,it is generally composed of sensors,actuators,controllers and controlled objects connected with each other.On this basis,people introduce the network to realize the interconnection of various components,thus forming a networked control system.The networked control system can realize resource sharing,high reliability,strong flexibility between devices the characteristics of low cost have attracted extensive attention and research.At present,networked control has become a hot topic.However,there are also many problems in networked control system.Due to the constraints of bandwidth and communication channel,there will always be network delay and packet loss in the process of data transmission.For this kind of phenomenon,when people analyze the stability of networked control system,they should always consider the impact of time delay on the performance of the system.In addition,there are a lot of nonlinear disturbances and uncertainties in the actual control process of most control systems,which often lead to the instability of the system.Therefore,this thesis mainly discusses the network delay and data packet loss in the transmission process of networked control system under the nonlinear condition.The main research of this thesis is divided into the following parts.(1)According to the characteristics of T-S fuzzy model and its wide application in the analysis of nonlinear control problems,a T-S fuzzy nonlinear networked control system is designed.Under the condition of multi time delay and nonlinearity,the stability of the fuzzy nonlinear networked control system is analyzed and discussed.A new stability criterion is established.(2)In this thesis,we consider the existence of network delay and packet loss in the stability of nonlinear networked control system.Assuming that it is nonlinear,we first construct a reasonable Lyapunov function according to the second theorem of Lyapunov stability and delay related conditions.We use a new Bessel Legendre integral inequality to deal with the problem with network delay and reduce the upper bound conservatism of network delay as much as possible.(3)Because in most nonlinear networked control systems,the state of the system is not necessarily completely measurable.In many cases,the state of the system needs to be reconstructed.Therefore,we will design an observer to consider that when the system is in a state that can not be directly measured,the stability of a new observer based nonlinear networked control system.