Research On Non-fragile State Estimation And Set-membership State Estimation Of Complex Networks With Communication Protocols

Complex networks consist of a large amount of interconnected and interactional nodes.In view of the complex structure,complex nodes and various complex factors,it is difficult to obtain the state information of all nodes directly through measurement.It is of great practical significance to estimate the state of all nodes on the basis of the available measurement information.In recent years,the state estimation problem of complex networks has become an important research topic in academia.But there are few attention of non-fragile state estimation problem and non-fragile set-membership state estimation problem of complex networks.Moreover,the large number of nodes and the complex connection structure of the complex networks may bring a lot of pressure to the data transmission of the communication network.In order to avoid data conflicts and reduce the unnecessary utilization of the limited network resources,it is necessary to use communication protocol which stipulates the priority of each node of accessing to communication networks at each transmission step.The main purpose of this paper is to study the state estimation problem of complex networks based on different communication protocols.Meanwhile,we discuss the effects of time-delay,uncertain inner coupling,incomplete measurement and bounded external disturbance on the state estimation performance.The main contents are summed up as follows:The non-fragile state estimation problem is investigated for a class of discrete complex networks with time-delay and bounded external disturbance under the stochastic communication protocol(SCP).The SCP is employed to determine which node has the priority of accessing to the communication network at each transmission step.For the considered complex networks,the novel non-fragile state estimator is designed by using the available measurement output after the transmission via the communication network,where the uncertainty of the estimator gain matrix is described in the random form.By utilizing stochastic analysis method and Lyapunov stability theory,sufficient criteria are given to ensure that the estimation error dynamics system is exponentially ultimate bounded in the mean-square sense.The minimum of the asymptotic upper bound of the output estimation error is given by solving the optimization problem.Furthermore,the design method of the desired estimator gains by means of LMI.A numerical example is provided to verify the validity of the proposed non-fragile state estimation method.We study the non-fragile set-membership state estimation problem under the round-robin(RR)protocol and the weighted try-once-discard(WTOD)protocol,respectively,for discrete time-varying complex networks with distributed delays,uncertain inner coupling and sensor saturation and time-varying nonlinear complex networks with time-delay and incomplete measurements.The RR protocol and the WTOD protocol are used to determine which node has the priority of accessing to the communication network at each transmission step.The interval matrix approach is utilized to depict the inner coupling matrix and incomplete measurements.For the considered complex networks,the novel non-fragile set-membership state estimators under the RR protocol and the WTOD protocol are designed,respectively,based on the available measurement output after the transmission via the communication network,where the estimator gain perturbation satisfies the norm bounded condition.With the aid of S-procedure and the recursive LMI,sufficient conditions are derived to ensure that the state estimation is confined to the ellipsoidal set.Moreover,the desired estimator gains and the minimum ellipsoid set of the corresponding estimation error can be obtained by solving the optimization problem.Simulations are provided to illustrate the feasibility of the proposed non-fragile set-membership state estimation algorithm.