钨铼热电偶长期稳定性的研究

关于钨铼热电偶稳定性的研究一直是高温测试领域的热点。详细介绍退火工艺制度与钨铼热电偶稳定性，保护管的绝缘材料的稳定性和相容性，核辐射条件下的稳定性及各种气氛下的稳定性。     

逻辑型DES的稳定性

关于逻辑型离散事件系统，一致稳定性，一致可吸收性及一致渐近稳定性理论等已得到证明。这里则给出其稳定性，可吸收性及渐近稳定性的结论。     

离散事件系统的稳定性

讨论离散事件系统（DES）的稳定性问题,给出DES稳定性,可吸收性和渐近稳定性有关结论,证明了关于DES稳定性的某些函数的存在性。     

混合动态系统的稳定性

讨论混合动态系统（HDS）的稳定性问题。首先给出关于HDS的稳定性、可吸收性和渐近稳定性的几个结论,然后给出关于HDS的Lyapunov稳定性定量。     

逻辑型DES的稳定性

关于逻辑型离散事件系统 ,一致稳定性 ,一致可吸收性及一致渐近稳定性理论等已得到证明。这里则给出其稳定性 ,可吸收性及渐近稳定性的结论     

柱式称重传感器密封性改进

应变式称重传感器是电子衡器称量系统的核心元器件,传感器的准确度和稳定性直接影响电子衡器称量系统的准确度和稳定性,称重传感器的稳定性尤为重要。而影响传感器稳定性最主要的因素就是传感器的密封性,文中给出了提高传感器的防护和密封性,从而有效保证传感器稳定性的几种方法。     

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。     

直流分布供电系统稳定性的分析与仿真

研究供电系统稳定性优化问题,针对直流分布供电系统中单独设计的功率模块级联后引起整个系统不稳定。由于系统连接,造成系统稳定性下降。为解决上述问题,提出了一种通过测量直流分布供电系统的稳定余度来判断系统稳定性的方法。在分析传统的判定稳定性方法缺点的基础上,根据Middlebrook判据,提出了禁止区域的概念,并进一步简化,推导出测量稳定余度的方法来判断级联系统的稳定性,并在SABER环境下对BOOST供电系统功率因数校正电路的稳定性。实验结果表明,方法能较为简便的判断直流分布供电系统的稳定性,同时对于其它供电系统的稳定性分析均有较好的参考价值。     

时滞神经网络的全局渐近稳定性分析

研究一类具有时滞的细胞神经网络的稳定性问题,利用Lyapunov—Krasovskii泛函的方法,给出时滞相关的稳定性判据。稳定性判据是以线性矩阵不等式的形式给出,可以很容易得出时滞的上界。在得到时滞相关的稳定性判据的同时也可以得到时滞无关的稳定性判据。数值算例说明其结果的优越性。     

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.     

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.     

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.     

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.     

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.     

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     

六足步行机的能量稳定性

本文详细讨论了六足步行机器人的能量稳定方法,给出并证明了六足步行机能量稳定裕量的一般计算公式,分析了横向及纵向行走的六足步行机采用三角步态时的能量稳定性,比较了能量稳定法和几何稳定法.     

Directional stability radius: a stability analysis tool for uncertain polynomial systems

Coefficients of characteristic polynomials for stable parametrically uncertain systems are allowed to perturb to some extent for stability. Stability radius is a useful tool to assess the allowance of the stability for the systems. To enhance its usefulness, we modify stability radius so that it takes into account of given restricted perturbations, which we call directional stability radius. For an application, we show shifted-Hurwitz stability conditions and a stability analysis method for interval polynomial systems using the directional stability radii.