Stability Analysis And Synthesis For A Class Of Linear Networked Control Systems

With the development of human technology,more and more requirements for industrial control are provided.Very recently,great changes in traditional control methods have been brought about owing to the rapid development of network communication and computer technology.The networked control systems have also become a hot topic in current research.The networked control systems are one kind of feedback control system with spatial distribution,which has the characteristics of realizing information sharing,remote control,improving the reliability and flexibility of the system and so on.However,due to the network itself,information will be limited by the network bandwidth in transit,which results in problems such as network-induced delay and data packet losses.These problems are the main reason for the performance degradation,even the instability of the networked control systems.In this paper,the stability of linear networked control systems is analyzed through Wirtinger inequality and Jensen inequality.Meanwhile,considering that the stability of the system will be affected by the uncertain factors such as external interference and the change of the system itself in the actual operation,the robust H_?stability analysis and controller design of the NCSs are carried out.Finally,the observer design is carried out in this case that the state of the system cannot be observed directly.The research contents mainly include the following points:(1)Firstly,the stability of linear networked control systems is analyzed based on Lyapunov stability theory.The model of NCSs is transformed into the system with input time delay h(t),and the stability criterion of NCSs is obtained by analyzing the stability problem of the system with time delay.An appropriate Lyapunov functional is constructed,and the integral terms from the derivative of Lyapunov functional are dealt with by Wirtinger inequality and Jensen inequality,and the derivation process is simplified.The stability criterion with less conservatism is obtained.Less decision variables are needed.The criterion is verified by two simulation results.(2)Because the actual control systems are often affected by external disturbances and uncertainties such as internal parameter errors,the robust H_?stabilization of networked control systems with parameter uncertainties is analyzed on the basis of theprevious chapter.The corresponding robust H_?stability criterion is obtained,and the design scheme of the robust H_?controller is given.Finally,the effectiveness of the controller design scheme is illustrated by Simulink simulation.(3)The previous chapters were studied based on the model of networked control systems.In this chapter,the problem that the system states cannot be directly measured is considered.In order to make the state of the new system asymptotically close to the state of the original system,the states of the system are reconstructed on the basis of the original system.The stability of networked control systems based on observer is studied in this part.The observer is constructed at the sensor end so that the state of the new structure and that of the original system are not delayed,which plays a compensation role for the network induced delay.The difficulty of system design is reduced,the performance of the system is improved,and the conservatism of the result is reduced.Then,the design scheme of the state feedback controller is proposed.