New criterion for delay-dependent absolute stability of Lurie system with interval time-varying delay

The delay-dependent absolute stability for a class of Lurie systems with interval time-varying delay is studied. By employing an augmented Lyapunov functional and combining a free-weighting matrix approach and the reciprocal convex technique, an improved stability condition is derived in terms of linear matrix inequalities （LMIs）. By retaining some useful terms that are usually ignored in the derivative of the Lyapunov function, the proposed sufficient condition depends not only on the lower and upper bounds of both the delay and its derivative, but it also depends on their differences, which has wider application fields than those of present results. Moreover, a new type of equality expression is developed to handle the sector bounds of the nonlinear function, which achieves fewer LMIs in the derived condition, compared with those based on the convex representation. Therefore, the proposed method is less conservative than the existing ones. Simulation examples are given to demonstrate the validity of the approach.

Passivity analysis for uncertain stochastic neural networks with discrete interval and distributed time-varying delays

The problem of passivity analysis is investigated for uncertain stochastic neural networks with discrete interval and distributed time-varying delays.The parameter uncertainties are assumed to be norm bounded and the delay is assumed to be time-varying and belongs to a given interval,which means that the lower and upper bounds of interval time-varying delays are available.By constructing proper Lyapunov-Krasovskii functional and employing a combination of the free-weighting matrix method and stochastic analysis technique,new delay-dependent passivity conditions are derived in terms of linear matrix inequalities（LMIs）.Finally,numerical examples are given to show the less conservatism of the proposed conditions.

On designing memory state feedback controller for linear systems with interval time-varying delay

This paper is concerned with the design of a memory state feedback controller for linear systems with interval time-varying delays.The time delay is assumed to be a time-varying continuous function belonging to a given interval,which means that the lower and upper bounds of time-varying delay are available.First,a less conservative delay-range-dependent stability criteria is proposed by using a new interval fraction method.In the process of controller synthesis,the history information of system is considered in the controller design by introducing the lower delay state.Moreover,the usual memoryless state feedback controller for the underlying systems could be considered as a special case of the memory case.Finally,two numerical examples are given to show the effectiveness of the proposed method.

Novel delay-dependent stability criteria for neural networks with interval time-varying delay

The problem of delay-dependent asymptotic stability for neurM networks with interval time-varying delay is investigated. Based on the idea of delay decomposition method, a new type of Lyapunov Krasovskii functional is constructed. Several novel delay-dependent stability criteria are presented in terms of linear matrix inequality by using the Jensen integral inequality and a new convex combination technique. Numerical examples are given to demonstrate that the proposed method is effective and less conservative.

Robust stability analysis for Markovian jumping stochastic neural networks with mode-dependent time-varying interval delay and multiplicative noise

This paper is concerned with the problem of robust stability for a class of Markovian jumping stochastic neural networks （MJSNNs） subject to mode-dependent time-varying interval delay and state-multiplicative noise. Based on the Lyapunov-Krasovskii functional and a stochastic analysis approach, some new delay-dependent sufficient conditions are obtained in the linear matrix inequality （LMI） format such that delayed MJSNNs are globally asymptotically stable in the mean-square sense for all admissible uncertainties. An important feature of the results is that the stability criteria are dependent on not only the lower bound and upper bound of delay for all modes but also the covariance matrix consisting of the correlation coefficient. Numerical examples are given to illustrate the effectiveness.

Improved delay-dependent robust H_∞ control of an uncertain stochastic system with interval time-varying and distributed delays

In this paper, the robust H∞control problem for a class of stochastic systems with interval time-varying and distributed delays is discussed. The system under study involves parameter uncertainty, stochastic disturbance, interval time-varying,and distributed delay. The aim is to design a delay-dependent robust H∞control which ensures the robust asymptotic stability of the given system and to express it in the form of linear matrix inequalities（LMIs）. Numerical examples are given to demonstrate the effectiveness of the proposed method. The results are also compared with the existing results to show its conservativeness.

Robust Stability Criteria for Neutral Systems with Interval Time-Varying Delays and Nonlinear Perturbations

This paper investigates the problem of delay-dependent robust stability analysis for a class of neutral systems with interval time-varying delays and nonlinear perturbations. Such nonlinear perturbations are with time-varying but norm-bounded characteristics. Based on a new Lyapunov-Krasovskii functional, together ,sith a free-weighting matrices technique, improved delay-dependent stability criteria are established. It is shown that less conservative results can be obtained in terms of linear matrix inequalities （LMIs）. Numerical examples are provided to demonstrate the effectiveness and less conservatism of the proposed approach.

Numerical solutions of linear quadratic control for time-varying systems via symplectic conservative perturbation

Optimal control system of state space is a conservative system, whose approximate method should be symplectic conservation. Based on the precise integration method, an algorithm of symplectic conservative perturbation is presented. It gives a uniform way to solve the linear quadratic control （LQ control） problems for linear timevarying systems accurately and efficiently, whose key points are solutions of differential Riccati equation （DRE） with variable coefficients and the state feedback equation. The method is symplectic conservative and has a good numerical stability and high precision. Numerical examples demonstrate the effectiveness of the proposed method.

一类区间时变时滞T-S模糊系统的鲁棒控制

针对一类区间时变时滞T-S模糊系统,研究了其时滞相关渐近稳定性以及控制器设计问题。基于Lyapunov稳定性理论和线性矩阵不等式(LMI)工具,并结合自由权矩阵方法,设计一个包含时滞区间均值在内的新Lyapunov-Krasovskii泛函,给出了改进的时滞T-S模糊系统渐近稳定的时滞相关准则。同时,根据并行分布补偿算法,给出了带有记忆的状态反馈模糊控制器的设计方法。最后,实例仿真表明了方法的有效性。

一种基于三端点区间数的改进DS/AHP方法

为了解决传统DS/AHP方法不适用于具有多位专家或专家意见富有分歧的群体决策问题,基于能够有效描述专家群组推理判断信息的三端点区间数对传统判断矩阵进行拓展,提出三端点区间数知识矩阵,基于三端点区间数中的一致性原理构建了用于从该矩阵中提取证据信息的基本概率分配函数的确定模型,在此基础上依据Dempster组合规则提出改进DS/AHP方法的操作步骤,应用一个数值模拟实例演示了该方法的具体操作过程。

基于T-S模糊模型的无人机混合H2/H∞控制

为了实现无人机稳定跟踪期望的轨迹,文章提出一种混合H2/H∞的控制策略,其将四旋翼无人机分为高度、位置和姿态3个子系统,并通过选择合适的前件变量对3个子系统分别建立T-S模糊误差模型,然后采用区间矩阵的方法描述升力系数、阻力系数和转动惯量等不确定项。为了保证无人机在微风等外部扰动的影响下能够稳定飞行,基于线性矩阵不等式方法和极点配置理论,文章设计了D稳定约束的混合H2/H∞控制器。四旋翼无人机的仿真结果验证了该控制策略的有效性。

New Results on H_∞ Control of Linear Systems with Interval Time-Varying Delays

This paper is focused on the H_(∞) control problem for linear systems with interval timevarying delays.By employing a reciprocally convex combination approach and a delay decomposition approach,some new delay-dependent bounded real lemmas(BRLs) are derived such that the closedloop system is asymptotically stable with a prescribed H_(∞) level.The BRLs are then used to solve the H_(∞) controller design by incorporating with the cone complementary approach.Three numerical examples are finally given to show the validity of the proposed method.

Delay-dependent Non-fragile H_∞ Control for Linear Systems with Interval Time-varying Delay

This paper considers the problem of delay-dependent non-fragile H∞control for a class of linear systems with interval time-varying delay. Based on the direct Lyapunov method, an appropriate Lyapunov-Krasovskii functional(LKF) with triple-integral terms and augment terms is introduced. Then, by using the integral inequalities and convex combination technique, an improved H∞performance analysis criterion and non-fragile H∞controller are formulated in terms of linear matrix inequalities(LMIs), which can be easily solved by using standard numerical packages. At last, two numerical examples are provided to demonstrate the effectiveness of the obtained results.

区间二型T-S模型网络控制系统的鲁棒H_∞控制

针对一类具有网络诱导时滞和参数不确定的网络控制系统,研究鲁棒H_∞控制器设计问题。基于区间二型T-S模型,通过构造合适的Lyapunov-Krasovskii泛函,引入自由权矩阵来表示Newton-Leibniz公式中各项之间的关系,加入一些附加项,运用不等式放缩和矩阵分解技巧,设计了使系统渐近稳定并满足H_∞性能指标的状态反馈控制器。最后,通过数值仿真实例验证了设计方法的有效性。

广义区间动力系统稳定的充分条件

讨论了连续广义区间动力系统在系统矩阵为区间矩阵时的稳定性问题·根据Gershgorin圆盘定理,在假设广义区间动力系统满足系统矩阵A主对角线元素均为负区间数的约束条件下,给出了一个使广义区间动力系统正则、无脉冲膜且稳定的充分条件·针对系统对应的Gershgorin圆盘半径较大的情况做了进一步讨论,使上述充分条件能够适用于更一般的情况·举出实例说明了此方法的正确性,并给出了一个判别区间矩阵为非奇异的充分必要条件·

一类连续模糊控制系统稳定性分析

基于区间矩阵的等价表示方法,将非线性时率的模糊控制系统稳定性分析问题转化为带有时变不确定性的线性系统鲁棒稳定性问题,并且采用最大隶属度的控制方法,得到了T-S模糊系统二次稳定的充分必要条件。仿真结果证明了此方法的有效性和优越性。

一类无界时变区间矩阵的稳定性分析

利用Coppel’s不等式对无界时变区间矩阵和具有分解的无界时变区间矩阵的稳定性进行了研究,给出了区间矩阵稳定的充分条件.最后通过两个数值实例说明了所给方法的有效性.

On the l_2-stability of time-varying linear and nonlinear discrete-time MIMO systems

New conditions are derived for the l2-stability of time-varying linear and nonlinear discrete-time multiple-input multipleoutput （MIMO） systems, having a linear time time-invariant block with the transfer function F（z）, in negative feedback with a matrix of periodic/aperiodic gains A（k）, k = 0,1, 2,... and a vector of certain classes of non-monotone/monotone nonlinearities φp（-）, without restrictions on their slopes and also not requiring path-independence of their line integrals. The stability conditions, which are derived in the frequency domain, have the following features： i） They involve the positive definiteness of the real part （as evaluated on ｜z｜ = 1） of the product of Г （z） and a matrix multiplier function of z. ii） For periodic A（k）, one class of multiplier functions can be chosen so as to impose no constraint on the rate of variations A（k）, but for aperiodic A（k）, which allows a more general multiplier function, constraints are imposed on certain global averages of the generalized eigenvalues of （A（k ＋ 1）,A（k））, k = 1, 2 iii） They are distinct from and less restrictive than recent results in the literature.

时变区间矩阵稳定的判别准则

本文用矩阵测度和Ｗａｚｅｗｓｋｉ不等式，给出了时变区间矩阵稳定和具有分解的时变区间矩阵稳定的充分条件，推广和改进了文［１－２］的工作。