Research On H_? Filter Methods For Time-Delay Systems

Time delay exists widely in the fields of communication net-work,signal transmission,network control,chemical and chemical process and boiler liquid level control.It often results in the system performance degradation or even instability,and also makes the analysis of the system more complicated.Therefore,the research on time delay system is of great significance.In addition,the signal will be affected by the external distur-bance during the transmission,which leads to the deviation of the received measured signal from the real signal.To reduce this deviation,people usu-ally apply the filtering method to filter the signal.The H_? filter,as one of the important filtering methods,introduces the H_? norm indicator in the design process and its ultimate goal is to design an effective filter satis-fying the criterion that the norm of output from the disturbance input to the filter error is less than a certain value,correspondingly,a stable filter is designed by using the measured signal to estimate the state of the sys-tem.This paper considers the problem of designing H_? filters with neutral time-varying delay systems and distributed delay systems.The contents are given as follows:Firstly,the problem of H_? filter for neutral time-delay system is con-cerned.First of all,the system model of filtering errors with the distur-bance of time-delay system is established.Then,combining the Lyapunov-Krasovskii stability theory,using the new integral inequality method and the reciprocally convex approach,a sufficient condition for the asymptot-ic stability of a time-delay system is obtained.Next,a design method of Luenberger-observer H_? filter is given,and finally the solution of the H_? filter is obtained.At last,simulation results show that the proposed stabili-ty consequence is lower conservative,and the designed H_? filter is feasible and effective.Secondly,the problem of H_? filter for distributed time-delay system is studied.First of all,the system model of filtering errors with external disturbances is established.Then,basing on the Lyapunov-Krasovskii sta-bility theory and new integral inequality,the sufficient conditions for the error system satisfying asymptotic stability are presented,and the design method of H_? filter is developed.At last,simulation results show the effi-ciency of the proposed method.