线性时变系统有限时间稳定性分析

针对一般非线性时变系统的有限时间稳定性分析问题,考虑到系统初始时刻在有限时间区间内的变化,本文分别提出了一般非线性时变系统的一致有限时间稳定性,一致收缩稳定性和固定调节时间一致收缩稳定性定义.针对一类线性时变系统,基于计算系统的所有轨线的包线的思想,本文分别给出了判定该类系统的收缩稳定性、固定调节时间收缩稳定性、一致有限时间稳定性、一致收缩稳定性、固定调节时间一致收缩稳定性的充分必要条件,同时给出了判定该类系统一致收缩稳定性及固定调节时间一致收缩稳定性的3个充分条件.进一步,本文将所得定理结果推广到了周期线性时变系统,所得结论为判定周期线性时变系统关于任意初始时刻的一致有限时间稳定性,一致收缩稳定性及固定调节时间一致收缩稳定性提供了理论依据.最后,以4个数值算例和两航天器相对运动过程为例验证了本文结果的正确性.     

互联网上机器人的遙控理论与方法综述

给出了系统的研究模型,指出系统控制和设计必须考虑的3个关键问题:稳定性、透明性和时延处理.阐述了4个主要的稳定性分析方法:Lyapunov稳定性、输入输出稳定性、无源稳定性和基于事件的稳定性,总结了这些方法的优势和局限性.接着,给出了几种主要的控制策略,指出了现有控制方法的优缺点.最后,提出了进一步的主要研究方向.     

土壤有机质稳定性特征与影响因子研究综述

本文阐述了土壤有机质(SOM)稳定性的影响因素及其稳定性特征,包括有机物质化学稳定性、物理稳定性和生物化学稳定性,探讨了通过分子特征,即元素组成、功能团、分子构像;有机物、无机物质或其它有机物质之间的分子间相互作用;有机质与微生物和酶之间的作用;以及水热条件对SOM稳定性的影响。     

简单电力系统静态稳定性分析及研究

文章以一个单机-无穷大系统为例,分析了影响电力系统静态稳定性的因素,介绍了静态稳定性的分析方法,提出了提高电力系统静态稳定性的措施。通过采取改善电力系统基本元件的特性和参数及采用附加装置等措施,提高了电力系统的静态稳定性。     

基于信息熵的供应链稳定性研究

针对供应链网络结构,从系统论的角度应用信息熵概念,定义了供应链的聚合度,建立了供应链系统稳定性的数学模型,通过聚合度、冗余度指标揭示了供应链的抗干扰能力和稳定性.分析了一个供应链的稳定性,得出聚合度、冗余度等指标可以反映供应链的稳定性.     

具有可变时滞的中立型随机系统的渐近性质

本文研究了一类具有可变时滞的中立型随机系统解的渐近性质.利用Lyapunov函数It、^o公式和上鞅收敛定理,得到了该系统解的一些几乎必然渐近稳定性与p阶均值渐近稳定性、几乎必然多项式渐近稳定性与p阶均值多项式渐近稳定性及几乎必然指数稳定性与p阶均值指数稳定性的充分判据.与经典的随机稳定性结论相比,本文所建立的判据充分利用了随机扰动项的作用,无须LV(扩散算子)的负定.     

两足步行机器人动态步行姿态稳定性及姿态控制

本文提出了一种新型两足步行机器人动态步行实时控制方法，引入了姿态稳定性和步态稳定性的概念，把两足动态步行控制分为姿态稳定性控制和步态稳定性控制两个相互联系的子系统，并从姿态稳定性分析出发，重点研究了各关节轨迹跟踪控制和系统整体动态平衡等问题，提出了姿态控制器的结构及设计方法．     

线性时变连续大系统的稳定性

本文应用导数不连续的李雅普诺夫函数结合比较原理,把时变高维大系统稳定性判定,简化为低维定常系统稳定性判定,省略了子系统稳定性判定条件,减弱了时变大系统稳定性条件。     

线性非定常系统的稳定性问题

大系统的理论与应用近十余年来有了相当大的发展,本文研究了这类系统的稳定性问题。首先对非定常线性系统的稳定性给出了一个简单的几何判据,然后建立起大系统的稳定性判据。最后考虑了大系统的结构,从而建立了简化的稳定性判据。     

带时滞的线性时变奇异系统的稳定性

通过比较方法建立了一类带时滞的线性时变奇异系统的稳定性判据,并讨论了相应的带有时滞的时变区间奇异系统的稳定性,给出了一个稳定性的比较定理。     

Robust stability and stabilizing controller design of fuzzy systems with discrete and distributed delays

In this paper, we consider delay-dependent stability conditions of Takagi-Sugeno fuzzy systems with discrete and distributed delays. Although many kinds of stability conditions for fuzzy systems with discrete delays have already been obtained, almost no stability condition for fuzzy systems with distributed delays has appeared in the literature. This is also true in case of the robust stability for uncertain fuzzy systems with distributed delays. Here we employ a generalized Lyapunov functional to obtain delay-dependent stability conditions of fuzzy systems with discrete and distributed delays. We introduce some free weighting matrices to such a Lyapunov functional in order to reduce the conservatism in stability conditions. These techniques lead to generalized and less conservative stability conditions. We also consider the robust stability of fuzzy time-delay systems with uncertain parameters. Applying the same techniques made on the stability conditions, we obtain delay-dependent sufficient conditions for the robust stability of uncertain fuzzy systems with discrete and distributed delays. Moreover, we consider the state feedback stabilization. Based on stability and robust stability conditions, we obtain conditions for the state feedback controller to stabilize the fuzzy time-delay systems. Finally, we give two examples to illustrate our results. Delay-dependent stability conditions obtained here are shown to guarantee a wide stability region.     

Remarks on three types of asymptotic stability

In this note, three types of asymptotic stability (Liapunov stability, Poincaré stability, and Zhukovkij stability) of motion in continuous autonomous dynamical systems are discussed. It is shown that each type of asymptotic stability can be geometrically characterized by omega limit set of an orbit of this type of stability.     

On partial detectability of the nonlinear dynamic systems

Conditions were obtained under which the uniform stability (uniform asymptotic stability) in one part of the variables of the zero equilibrium position of the nonlinear nonstationary system of ordinary differential equations implies the uniform stability (uniform asymptotic stability) of this equilibrium position relative to another, larger part of variables. Conditions were also obtained under which the uniform stability (uniform asymptotic stability) in one part of variables of the “partial” (zero) equilibrium position of the nonlinear nonstationary system of ordinary differential equations implies the uniform stability (uniform asymptotic stability) of this equilibrium position. These conditions complement a number of the well-known results of the theory of partial stability and partial detectability of the nonlinear dynamic systems. Application of the results obtained to the problems of partial stabilization of the nonlinear control systems was considered.     

Stability analysis of Takagi-Sugeno stochastic fuzzy Hopfield neural networks with discrete and distributed time varying delays

In this paper, the global stability problem of Takagi-Sugeno (T-S) stochastic fuzzy Hopfield neural networks (TSSFHNNs) with discrete and distributed time varying delays is considered. A novel LMI-based stability criterion is obtained by using Lyapunov functional theory to guarantee the asymptotic stability of TSSFHNNs with discrete and distributed time varying delays. Here we choose a generalized Lyapunov functional and introduce a parameterized model transformation with free weighting matrices to it, in order to obtain stability region. In fact, these techniques lead to generalized and less conservative stability condition that guarantee the wide stability region. The proposed stability conditions are demonstrated with numerical examples. Comparison with other stability conditions in the literature shows that our conditions are the more powerful ones to guarantee the widest stability region.     

Finite‐time stability and stabilization of semi‐Markovian jump systems with time delay

Semi‐Markovian jump systems are more general than Markovian jump systems in modeling practical systems. On the other hand, the finite‐time stochastic stability is also more effective than stochastic stability in practical systems. This paper focuses on the finite‐time stochastic stability, exponential stochastic stability, and stabilization of semi‐Markovian jump systems with time‐varying delay. First, a new stability condition is presented to guarantee the finite‐time stochastic stability of the system by using a new Lyapunov‐Krasovskii functional combined with Wirtinger‐based integral inequality. Second, the stability criterion is further proved to guarantee the exponential stochastic stability of the system. Moreover, a controller design method is also presented according to the stability criterion. Finally, an example is provided to illustrate that the proposed stability condition is less conservative than other existing results. Additionally, we use the proposed method to design a controller for a load frequency control system to illustrate the effectiveness of the method in a practical system of the proposed method.     

不确定多重状态时滞离散系统的LMI鲁棒稳定条件

研究了具有多重状态时滞的凸多面体不确定离散系统的鲁棒稳定性分析问题．基于参数依赖的李亚普诺夫稳定性和线性矩阵不等式推导出使得时滞鲁棒稳定系统鲁棒稳定的充分条件．应用此条件，通过测试一组线性矩阵不等式的可解性即可达到判定系统的鲁棒稳定性的目的．因为使用了参数依赖的李亚普诺夫稳定性思想，此鲁棒稳定条件比基于二次稳定概念的稳定条件的保守性更小．算例验证了结果．     

Biquadratic stability of uncertain linear systems

Deals with the problem of stability analysis for linear systems with uncertain real, possibly time-varying, parameters. A robust stability approach based on a Lyapunov function which depends quadratically on the uncertain parameters as well as in the system state is proposed. This robust stability approach, referred to as biquadratic stability, is suited to deal with uncertain real parameters with magnitude and rate of change which are confined to a given convex region. A linear matrix inequality based sufficient condition for biquadratic stability is developed. The proposed robust stability analysis method includes quadratic stability and affine quadratic stability as particular cases     

Novel development of Lyapunov stability of motion

The paper presents a refined analysis of the influence of initial data on dynamic behaviour and stability properties of non-stationary systems. As a result, new stability properties are discovered and defined as well as the corresponding stability domains. Furthermore, general necessary conditions are established for asymptotic stability of the unperturbed motion of these systems, the instantaneous asymptotic stability domain of which can be either time-invariant or time-varying and then possibly asymptotically contractive. It is shown that the classical Lyapunov stability conditions cannot be applied to the stability test as soon as the system instantaneous domain of asymptotic stability is asymptotically contractive. In order to investigate asymptotic stability of the motion in such cases novel criteria are established. Under the criteria the Eulerian derivative of a system Lyapunov function may be non-positive only and still guarantee asymptotic stability of the unperturbed motion

The results are illustrated by examples.