Mixed <Emphasis Type="Italic">H</Emphasis><Subscript>2</Subscript>/<Emphasis Type="Italic">H</Emphasis><Subscript>∞</Subscript> filtering for a class of high-speed sampling uncertain systems

The problem of mixed H2/H∞ filtering for polytopic Delta operator systems is investigated. The aim is to design a linear asymptotically stable filter which guarantees that the filtering error system has different performances in different filtering channels. Based on a parameter-dependent Lyapunov function, a new mixed H2/H∞ performance criterion is presented. Upon this performance criterion, a sufficient condition for the full-order mixed H2/H∞ filter is derived in terms of linear matrix inequalities. The filter can be obtained from the solution of a convex optimization problem. The proposed filter design procedure is less conservative than the strategy based on the quadratic stability notion. A numerical example is given to illustrate the feasibility of the proposed approach.     

Improved Parameter-dependent H∞ Filtering for Polytopic Delta Operator Systems

The problem of H∞ filtering for polytopic Delta operator linear systems is investigated. An improved H∞ performance criterion is presented based on the bounded real lemma. Upon the improved performance criterion, a sufficient condition for the existence of parameter-dependent H∞ filtering is derived in terms of linear matrix inequalities. The designed filter can be obtained from the solution of a convex optimization problem. The filter design makes full use of the parameter-dependent approach, which leads to a less conservative result than conventional design methods. A numerical example is given to illustrate the effectiveness of the proposed approach.     

Improved Parameter-dependent H_∞ Filtering for Polytopic Delta Operator Systems

The problem of H∞ filtering for polytopic Delta operator linear systems is investigated. An improved H∞ performance criterion is presented based on the bounded real lemma. Upon the improved performance criterion, a sufficient condition for the existence of parameter-dependent H∞ filtering is derived in terms of linear matrix inequalities. The designed filter can be obtained from the solution of a convex optimization problem. The filter design makes full use of the parameter-dependent approach, which leads t...     

考虑有限字长影响的离散时间非脆弱H∞滤波

The nonfragile H_∞filtering problem affected by finite word length (FWL) for linear discrete-time systems is investigated in this paper.The filter to be designed is assumed to be with additive gain variations,which reflect the FWL effects on filter implementation.A notion of structured vertex separator is proposed to deal with the problem and exploited to develop sufficient conditions for the nonfragile H_∞filter design in terms of a set of linear matrix inequalities (LMIs).The design renders the augmented system asymptotically stable and guarantees the H_∞attenuation level less than a prescribed level.A numerical example is given to illustrate the effect of the proposed method.     

Fuzzy H_∞ Filter Design for a Class of Nonlinear Systems with Time Delays via LMI

This paper develops fuzzy H_∞filter for state estimation approach for nonlinear discrete- time systems with multiple time delays and unknown bounded disturbances.We design a stable fuzzy H_∞filter based on the Takagi-Sugeno (T-S) fuzzy model,which assures asymptotic stability and a prescribed H_∞index for the filtering error system.Sufficient condition for the existence of such a filter is established by solving the linear matrix inequality (LMI) problem.The LMI problem can be efficiently solved with global convergence using the interior point algorithm.Simulation examples are provided to illustrate the design procedure of the proposed method.     

Enhanced H∞ Filtering for Continuous-time State-delayed Systems

The H∞ filtering problem for continuous-time polytopic uncertain time-delay systems is investigated. Attention is focused on the design of full-order filters guaranteeing a prescribed H∞ attenuation level for the filtering error system. First, a simple alternative proof is given for an improved linear matrix inequality （LMI） representation of H∞ performance. Then, based on the performance criterion which keeps Lyapunov matrices out of the product of system dynamic matrices, a suficient condition for the existence of robust estimators is formulated in terms of LMIs, and the corresponding filter design is cast into a convex optimization problem which can be effciently handled by using standard numerical algorithms. It is shown that the proposed design strategy allows the use of parameter-dependent Lyapunov functions and hence it is less conservative than some earlier results. A numerical example is employed to demonstrate the feasibility and advantage of the proposed design.     

Enhanced H_∞ Filtering for Continuous-time State-delayed Systems

The H∞ filtering problem for continuous-time polytopic uncertain time-delay systems is investigated. Attention is focused on the design of full-order filters guaranteeing a prescribed H∞ attenuation level for the filtering error system. First, a simple alternative proof is given for an improved linear matrix inequality (LMI) representation of H∞ performance. Then, based on the performance criterion which keeps Lyapunov matrices out of the product of system dynamic matrices, a suficient condition for the exi...     

Robust H ∞ filter design for time-delay systems with saturation

This paper investigates the H∞ filtering problem for a class of linear continuous-time systems with both time delay and saturation. Such systems have time delay in their state equations and saturation in their output equations, and their process and measurement noises have unknown statistical characteristics and bounded energies. Based on the Lyapunov-Krasovskii stability theorem and the linear matrix inequalities (LMIs) technique, a generalized dynamic filter architecture is proposed, and a filter design method is developed. The linear H∞ filter designed by the method can guarantee the H∞ performance. The parameters of the designed filter can be obtained by solving a kind of LMI. An illustrative example shows that the design method proposed in this paper is very effective.     

Observer-based H_∞ Filtering of 2-D Singular System Described by Roesser Models

This paper discusses the problem of the H∞ filtering for discrete time 2-D singular Roesser models (2-D SRM). The purpose is to design an observer-based 2-D singular filter such that the error system is acceptable, jump modes free and stable, and satisfies a pre-specified H∞ performance level. By general Riccati inequality and bilinear matrix inequalities (BMI), a sufficient condition for the solvability of the observer-based H∞ filtering problem for 2-D SRM is given. A numerical example is provided to demonstrate the applicability of the proposed approach.     

H_∞ Filter Design for Discrete-time Systems with Missing Measurements

For packet-based transmission of data over a network, or temporary sensor failure, etc., data samples may be missing in the measured signals. This paper deals with the problem of H∞ filter design for linear discrete-time systems with missing measurements. The missing measurements will happen at any sample time, and the probability of the occurrence of missing data is assumed to be known. The main purpose is to obtain both full-and reduced-order filters such that the filter error systems are exponentially mean-square stable and guarantee a prescribed H∞ performance in terms of linear matrix inequality (LMI). A numerical example is provided to demonstrate the validity of the proposed design approach.     

Robust H_∞ Filtering for a Class of Uncertain Lurie Time-delay Singular Systems

This paper deals with the problem of the robust H∞filtering for a class of Lurie singular systems with state time-delays, parameter uncertainties and unknown statistics characteristics but with limited power disturbance,aiming to design a robustly stable filter such that the uncertain Lurie time-delay singular systems are not only regular,impulse free and stable,but also have a prescribed level of H∞performance for the filtering error dynamics for all admissible uncertainties．A sufficient condition for the existence of such a filter is proposed in terms of linear matrix inequalities (LMIs)．When a solution to this set of LMIs exists,the parametric matrices of a desired filter can be easily obtained using LMI toolbox．     

H_∞ Control for 2-D Discrete State Delayed Systems in the Second FM Model

This paper is concerned with the problem of H_∞control for two-dimensional (2-D) discrete state delay systems described by the second Fornasini and Marchesini (FM) state- space model.A sufficient condition to have an H_∞noise atten- uation for this 2-D system is given in terms of a certain linear matrix inequality (LMI).The optimal H_∞controller is obtained by solving a convex optimization problem.Finally,a simulation example is given to illustrate the effectiveness of the proposed result.     

Reliable H-infinity filtering for linear systems with sensor saturation

In this paper, a new reliable H-infinity filter design problem is proposed for a class of continuous-time systems with sensor saturation and failures. Attention is focused on the analysis and synthesis problems of a full order reliable H-infinity filter such that the filtering error dynamics is asymptotically stable with a guaranteed disturbance rejection attenuation level γ. It is shown that the filtering error dynamics obtained from the original system plus the filter can be modeled by a linear system with sector bounded nonlinearity. The design conditions are given in terms of solutions to a set of linear matrix inequalities (LMIs). These conditions are then considered in a convex optimization problem with LMIs constraints in order to design an optimal reliable H-infinity filter. A numerical example is given to illustrate the effectiveness of the proposed results.     

H_∞ Control with Multiple Delays in Measurements

Based on an innovation analysis method in the Krein space,a sufficient and necessary condition is given for the existence of the solution of H_∞control problem for a linear continuous- time system with multiple delays.By introducing a re-organized innovation sequence,the H_∞control problem with delayed measurements is converted into a linear quadratic(LQ)problem and a delay- free H_2 estimation problem in the Krein space.The controller is given in terms of two forward Riccati equations and a backward Riccati equation.     

离散时间系统量化动态输出反馈的H∞控制

The problem of quantized dynamic output feedback H_∞control for discrete-time linear time-invariant(LTI)systems is investigated in this paper.The quantizer considered is dynamic and composed of an adjustable"zoom"parameter and a static quantizer.Static quantizer ranges are of practical significance and are fully considered.First,taking quantization errors into account, a quantized control strategy is dependent not only on the controller states but also on the system measurement outputs,which is proposed such that the quantized closed-loop system is asymptotically stable and with a prescribed H_∞performance bound.Then, on the basis of this result,an iterative LMI-based optimization algorithm is developed to optimize the static quantizer ranges to meet H_∞performance requirements for closed-loop systems.An example is presented to illustrate the effectiveness of the proposed method.     

Robust H_∞ control for discrete-time polytopic uncertain systems with linear fractional vertices

The robust H∞ control problem for discrete-time uncertain systems is investigated in this paper. The uncertain systems are modelled as a polytopic type with linear fractional uncertainty in the vertices. A new linear matrix inequality (LMI) characterization of the H∞ performance for discrete systems is given by introducing a matrix slack variable which decouples the matrix of a Lyapunov function candidate and the parametric matrices of the system. This feature enables one to derive sufficient conditions for discrete uncertain systems by using parameter-dependent Lyapunov functions with less conservativeness. Based on the result, H∞ performance analysis and controller design are carried out. A numerical example is included to demonstrate the effectiveness of the proposed results.     

具有测量数据部分丢失的离散系统的H∞滤波器设计

For packet-based transmission of data over a network, or temporary sensor failure, etc., data samples may be missing in the measured signals. This paper deals with the problem of H∞ filter design for linear discrete-time systems with missing measurements. The missing measurements will happen at any sample time, and the probability of the occurrence of missing data is assumed to be known. The main purpose is to obtain both full-and reduced-order filters such that the filter error systems are exponentially mean-square stable and guarantee a prescribed H∞ performance in terms of linear matrix inequality (LMI). A numerical example is provided to demonstrate the validity of the proposed design approach.     

The Lifting Technique for Sampled-data Systems:Useful or Useless?

The lifting technique is now a well recognized tool for H_∞design and analysis of sampled- data systems.However,the efficiency of the method depends on the structure of the problem.The structure of the H_∞sensitivity problem is analyzed in this paper.And the constraints on the H_∞-optimization problem and on the design parameters in lifting design are also discussed.Under such constraints the resulting performance from the design is generally low.Therefore,the lifting technique can not be recommended as a synthesis tool for the sampled-data systems.An example is also given in the paper.     

基于观测器的2-D奇异系统Roesser模型的H∞滤波

This paper discusses the problem of the H∞ filtering for discrete time 2-D singular Roesser models (2-D SRM). The purpose is to design an observer-based 2-D singular filter such that the error system is acceptable, jump modes free and stable, and satisfies a pre-specified H∞ performance level. By general Riccati inequality and bilinear matrix inequalities (BMI), a sufficient condition for the solvability of the observer-based H∞ filtering problem for 2-D SRM is given. A numerical example is provided to demonstrate the applicability of the proposed approach. Key words 2-D singular systems, jump modes, general Riccati inequality, bilinear matrix i