D-stability robustness for linear discrete uncertain singular systems with delayed perturbations

In this paper, the robust D-stability problem (i.e. the robust eigenvalue-clustering in a specified circular region problem) of linear discrete singular systems with both structured (elemental) parameter uncertainties and delayed perturbations is investigated. Under the assumptions that the linear discrete nominal singular system is regular and causal, and has all its finite eigenvalues lying inside a specified circular region, by using the maximum modulus principle and the spectral radius of matrices, a new sufficient condition is proposed to preserve the assumed properties when both structured parameter uncertainties and delayed perturbations are added into the linear discrete nominal singular system. When all the finite eigenvalues lie inside the unit circle of the z-plane, the proposed criterion will become the stability robustness criterion. The proposed criterion is mathematically proved and numerically shown, respectively, to be less conservative than the existing ones reported recently.     

具有多输入时滞的不确定广义系统的时滞相关鲁棒镇定

研究具有多输入时滞及参数不确定性的广义系统的时滞相关鲁棒镇定问题. 首先利用LMI给出相应的标称系统的时滞相关镇定准则. 然后, 基于这个准则, 设计状态反馈控制器, 使得对任何允许的不确定参数相应的闭环系统是正则, 稳定, 无脉冲的. 最后的数值算例表明所提方法是有效的.     

Delay-Dependent Robust Stability Criteria for Two Classes of Uncertain Singular Time-Delay Systems

In this note, the delay-dependent robust stability criteria for two classes of singular time-delay systems with norm-bounded uncertainties are investigated. First, without using model transformation and bounding technique for cross terms, an improved delay-dependent stability criterion for the nominal singular time-delay system is established in terms of strict linear matrix inequalities (LMIs). Then, based on this criterion, the delay-dependent robust stability criteria for two classes of uncertain singular time-delay systems are proposed, which ensure that the systems are regular, impulse free and asymptotically stable for all admissible uncertainties. Numerical examples are proposed to illustrate the less conservatism of the obtained results     

Robust stability and stabilization of discrete singular systems with interval time-varying delay and linear fractional uncertainty

The robust stability and robust stabilization problems for discrete singular systems with interval time-varying delay and linear fractional uncertainty are discussed. A new delay-dependent criterion is established for the nominal discrete singular delay systems to be regular, causal and stable by employing the linear matrix inequality (LMI) approach. It is shown that the newly proposed criterion can provide less conservative results than some existing ones. Then, with this criterion, the problems of robust stability and robust stabilization for uncertain discrete singular delay systems are solved, and the delay-dependent LMI conditions are obtained. Finally, numerical examples are given to illustrate the e?ectiveness of the proposed approach.     

不确定线性多时变时滞系统的时滞相关鲁棒控制

提出一种积分不等式新方法，讨论不确定线性多时变时滞系统的鲁棒稳定性以及鲁棒稳定化问题，首先利用Park不等式建立了基于二次型项的积分不等式，利用这一不等式获得了系统基于LMI的时滞相关、时滞导数相关鲁棒稳定条件；然后利用这一条件给出了时滞状态反馈控制器的一种新的设计方法，数值例子说明了所得结论具有较小的保守性。     

含离散与分布时滞的不确定中立型系统鲁棒稳定性新判据

基于离散时滞分解思想,通过构造一种新的Lyapunov-Krasovskii泛函并结合Jensen不等式技巧,建立了线性矩阵不等式(LMI)形式的时滞相关鲁棒稳定性新判据.该方法允许中立时滞项的系数矩阵存在时变不确定性,增强了系统的鲁棒性能.同时针对分布时滞项难于处理的问题,构造了其分解计算泛函.数值算例表明所得结论的有效性和更低的保守性.     

离散多时滞系统的D稳定鲁棒容错控制

针对离散多时滞系统,设计了一种D稳定鲁棒容错控制器。首先以传感器失效为例,推导出了使系统D稳定的充分条件。然后依次推广到执行器失效以及系统参数不确定的情况。所设计的鲁棒容错控制器既能保持系统的稳定性,又能使系统满足一定的性能要求,且工程上易于实现。最后通过仿真示例验证了文中方法的正确性,并对仿真结果进行了分析。     

不确定奇异时滞系统时滞依赖鲁棒镇定

This paper considers the problem of delay-dependent robust stabilization for uncertain singular delay systems.In terms of linear matrix inequality (LMI) approach,a delay-dependent stability criterion is given to ensure that the nominal system is regular,impulse free,and stable.Based on the criterion,the problem is solved via state feedback controller,which guarantees that the resultant closed-loop system is regular,impulse free,and stable for all admissible uncertainties.An explicit expression for the desired controller is also given.Some numerical examples are provided to illustrate the validity of the proposed methods.     

Delay-dependent criteria for the robust stability of systems with time-varying delay

The problem of delay-dependent robust stability for systems with time-varying delay has been considered. By using the S-procedure and the Park's inequality in the recent issue, a delay-dependent robust stability criterion which is less conservative than the previous results has been derived for time-delay systems with time-varying structured uncertainties. The same idea has also been easily extended to the systems with nonlinear perturbations. Numerical examples illustrated the effectiveness and the improvement of the proposed approach.     

New results on robust H-infinity control for discrete-time systems with interval time-varying delays

This paper deals with delay-dependent robust H-infinity control for uncertain discrete-time systems with interval time-varying delay. By using a new Lyapunov functional and the convex combination method, a new delay-dependent stability criterion is established. Some redundant variable matrices are removed in the new conditions, which makes the obtained results more efficient. Then, an iterative algorithm based on the cone complementarity Linearization method is proposed to obtain the delay-dependent robust H-infinity controller. Numerical examples are given to show the effectiveness of the proposed method.     

多丢包不确定离散系统的鲁棒Kalman滤波

研究了同时具有不确定性和多丢包情况下的离散时变系统的鲁棒滤波问题, 其中的不确定性是时变的、范数有界的, 且存在于系统的状态矩阵和输出矩阵中. 通过把多丢包问题建模成系统模型中的随机参数, 在允许的不确定性情况下, 给出了估计误差方差的上界, 并进一步基于矩阵范数的意义最小化该上界. 结果表明, 通过求解两个Riccati差分方程, 可以设计鲁棒滤波器. 最后, 提出适合在线计算的鲁棒滤波算法, 并通过仿真实例表明所提算法的有效性和实用性.     

Robust controller design for input‐delayed systems using predictive feedback and an uncertainty estimator

This paper deals with the problem of stabilizing a class of input‐delayed systems with (possibly) nonlinear uncertainties by using explicit delay compensation. It is well known that plain predictive schemes lack robustness with respect to uncertain model parameters. In this work, an uncertainty estimator is derived for input‐delay systems and combined with a modified state predictor, which uses current available information of the estimated uncertainties. Furthermore, based on Lyapunov–Krasovskii functionals, a computable criterion to check robust stability of the closed‐loop is developed and cast into a minimization problem constrained to an LMI. Additionally, for a given input delay, an iterative‐LMI algorithm is proposed to design stabilizing tuning parameters. The main results are illustrated and validated using a numerical example with a second‐order dynamic system. Copyright © 2016 John Wiley & Sons, Ltd.     

Delay-dependent H-infinity control for continuous time-delay systems via state feedback

The delay-dependent H-infinity analysis and H-infinity control problems for continuous time-delay systems are studied. By introducing an equality with some free weighting matrices, an improved criterion of delay-dependent stability with H-infinity performance for such systems is presented, and a criterion of existence and some design methods of delay-dependent H-infinity controller for such systems are proposed in term of a set of matrix inequalities, which is solved efficiently by an iterative algorithm. Further, the corresponding results for the delay-dependent robust H-infinity analysis and robust H-infinity control problems for continuous time-delay uncertain systems are given. Finally, two numerical examples are given to illustrate the efficiency of the proposed method by comparing with the other existing results.     

一类不确定切换奇异时滞系统的时滞依赖鲁棒镇定

针对一类不确定切换奇异时滞系统,对其鲁棒镇定问题进行了研究.首先利用多李亚普诺夫泛函方法和线性矩阵不等式工具,通过引入适当的自由权矩阵,在适当的切换律下,给出了基于严格线性矩阵不等式表示的标称自治切换奇异系统正则、无脉冲且渐近稳定的时滞依赖条件;然后基于此条件,通过设计相应的状态反馈子控制器,得到了保证闭环系统对所有允许的不确定性是正则、无脉冲且渐近稳定的时滞依赖条件,同时给出了子控制器的显示表达式.数值算例表明该方法的有效性.     

Delay-dependent robust stabilization of uncertain state-delayed systems

This paper concerns a problem of robust stabilization of uncertain state-delayed systems. A new delay-dependent stabilization condition using a memoryless controller is formulated in terms of matrix inequalities. An algorithm involving convex optimization is proposed to design a controller guaranteeing a suboptimal maximal delay such that the system can be stabilized for all admissible uncertainties.