Robust H_? Filtering For Delta Operator Networked Systems With Multiple Constraints

Networked control systems(NCSs)are developed on the basis of traditional control systems.Compared with point-to-point control system,networked control system has obvious advantages.For example,installation is simple and convenient,information can be shared,and expansion and maintenance is more convenient.However,due to the limitation of bandwidth,while enjoying the convenience of the network system,we must face the adverse effects of the network system.These adverse effects mainly include:system transmission delay,data packet transmission constraints and loss,which will affect the recovery of the signal at the receiving end to a certain extent.In order to restore the transmission signal more accurately,network system filtering estimation is particularly important.Compared with the classical Kalman filtering method, H_? filtering method has more advantages in processing system uncertainty.In addition,delta operator method can not only solve the ill-conditioned problem caused by traditional shift operator in high-speed sampling,but also integrate the filtering problem of continuous and discrete systems into a unified framework.Therefore,using delta operator method to study the filtering of network system has important practical significance.This thesis focuses on the H_? filtering of delta operator networked systems with stochastic delay,packet loss,communication constraints et al.The main results are as follows:1)Considering the constraints of random delays and data loss in the network,the delta operator method is used to design H_? filter for networked control systems.The phenomenon of data packet loss in the network system to be studied is described as a stochastic process with Bernoulli distribution.Then the state expression of the H_? filter to be designed is given.Then the filtering error model of the system is obtained.By constructing Lyapunov functional,the condition that the system satisfies the asymptotic stability is given,by solving the linear matrix inequality(LMIs),the corresponding filter parameters are obtained.Finally,the effectiveness of the design algorithm is verified by a set of simulation experiments.2)Considering the existence of random delay and data packet loss in uncertain network systems,an uncertain system model with both packet loss and random delay in network systems is established in the field of delta operator.The time delay problem of the system is described by Markov jump model,and the H_? filter is designed for the system.Then the minimum H_? performance index of the system is obtained by solving LMIs satisfying the sufficient conditions of asymptotic stability of the filtering error system,and the parameters of the designed filter are also obtained.Finally,the effectiveness of the algorithm can be verified by a set of numerical examples.3)The problem of robust H_? filtering for networked control systems with random delays in communication-constrained environments is studied.In this thesis,the filtering error system to be studied is modeled as a delta operator model with uncertain parameters.The state model of the H_? filter is given,and an appropriate Lyapunov function is constructed.By solving LMIs,we can get the sufficient condition of stochastic stability and the parameters of the designed filter.Corresponding parameters of the filter are given.Finally,a simulation example is given to verify the effectiveness of the design method.