H_? Control For A Class Of Networked Control Systems By Using Input Delay Method

With the development of modern industry and the expansion of production scale,the control process is becoming complex,the structure parameters of systems are time-varying,strong coupling,extremely nonlinear,uncertainty,diversity,and so on.These factors put forward high requirements for the control theory.As a feedback control system,a networked control system is a kind of spatial distributed feedback control systems.And the data signal transmission of the system is based on network communication channel.Research on the networked control systems has attracted many scholars,and there are many results about this topic.But there are still many problems which come from the actual situation need to be solved.In this paper,the H_?stability analysis and the controller design of linear networked control systems are studied by using the input delay method.The H_?stability analysis and controller design of the nonlinear networked control systems are studied by using the Takagi-Sugeno(T-S)fuzzy model.The research work of this paper mainly includes the following aspects:(1)The stability of linear networked control systems is analyzed by using the input delay method and the state feedback controller design methods are given.At first,we give a linear time-invariant system model based on network control,which takes into account the network induced delay and data packet loss.Then the input delay is defined to make use of the existing research results about time-delay systems and sampled-data systems.A new Lyapunov-Krasovskii(L-K)functional is constructed by combining the relative convex combination method and the first order derivative of the time delay.Finally,the numerical examples are provided to show that the stability criterion is less conservative,and the scheme of the proposed state feedback controller is effective.(2)Considering that in the actual environment,the influence of external interference on the controlled object is often inevitable.In this case,we study the problem of the H_?controller design of linear networked control systems.Firstly,the networked control system models with external disturbances are given.Then by using the augmented L-K functional method,the functional of the existing literature can be improved.And in order to further reduce the conservatism,we use the improved free weighting matrix approach.Finally,by comparing the results of numerical simulation with that of the existing literature,the proposed stability criterion is less conservative,and the effectiveness of the proposed controller design scheme is verified.(3)The linear networked control systems are considered in the above sections,but in practice,it is often faced with the control problem of the nonlinear networked control systems.So we use the T-S fuzzy model to describe the nonlinear networked control systems.At the same time,we pay attention to the problem that the membership functions of the system are different from the ones of controller.Then a new L-K functional is defined to capture the characteristic of sampled-data systems by using input delay approach.By calculating derivation of the functional,the corresponding controller design scheme is given.In the end,the validity of the results is compared with the existing results by using numerical simulation.At the end of this paper,the research content of this paper and the direction of future research area are summarized.