多时变状态和控制时滞系统的绝对稳定性

研究了具有多时变状态和控制时滞的Lurie控制系统基于线性矩阵不等式(LMI)的绝对稳定性条件.首先,构造了关于Lyapunov泛函中正定矩阵和积分项系数等自由参数的LMI,获得了系统时滞无关绝对稳定条件.进一步引入自由权矩阵来表示牛顿-莱布尼兹公式中各项的相互关系,得到了系统绝对稳定的时滞相关条件.最后,通过一个实例阐述了本文方法的有效性和相比已有结果的优越性.     

时滞随机系统的稳定性分析

针对一类时变时滞随机系统,研究其渐近稳定性问题。通过构造李亚普诺夫函数,引用适当的自由权矩阵,利用积分等式、积分不等式,给出系统渐进稳定的时滞相关的充分条件,其结果用线性矩阵不等式形式表示.用数值算例说明方法的有效性。     

转移概率部分未知的时滞不确定Markov跳跃系统稳定性分析

本文研究转移概率部分未知的时滞不确定的Markov 跳跃系统随机稳定性问题,基于Lyapunov稳定理论,构造合适的Lyapunov泛函,使用自由权矩阵技术和凸结合技术来估计积分项的上界,同时也充分考虑时滞下界和上界的关系,得到保证Markov 跳跃系统随机稳定性的充分性条件,该条件以线性矩阵不等式的形式表出。最后,一个数值例子和其仿真验证了我们所提方法的有效性和优越性。     

多胞不确定型多时变时滞系统的稳定性

采用积分等式方法处理Lyapunov-Krasovskii泛函导数中的交叉项, 利用牛顿–莱布尼兹公式和自由权矩阵来保留状态的导数项, 标称系统的稳定性条件中的系统矩阵和Lyapunov矩阵得以分离, 再通过参数依赖Lyapunov-Krasovskii泛函得到多胞不确定型系统的鲁棒稳定性结论, 最后数值算例说明稳定性条件的有效性.     

一类具有扇区非线性的时变时滞系统的绝对稳定性

讨论一类具有扇区非线性的时变时滞系统的绝对稳定性问题.基于时滞分段的思想,构造一种新的Lyapunov 泛函,进一步应用自由权矩阵结合积分不等式方法,并充分考虑时变时滞和时滞上界之间的关系,得到了基于LMI的具有更低保守性的时滞相关绝对稳定条件.最后,数值实例表明所提方法的有效性和相比已有结果的优越性.     

线性时滞系统的时滞相关鲁棒稳定性新判据

讨论具有多个范数有界不确定的线性时滞系统的时滞相关鲁棒稳定性.利用Lyapunov-Krasovskii泛函方法,结合自由权矩阵思想,在Lyapunov-Krasovskii泛函的导数中恰当地引入一些自由矩阵,获得了基于线性矩阵不,等式的时滞相关稳定充分条件.该条件较已有结论不仅形式简单,而且具有更小的保守性.     

不确定变时滞系统的鲁棒非脆弱H∞控制

针对一类参数不确定时变时滞线性系统,研究了鲁棒非脆弱H∞控制器的设计问题。首先利用积分不等式和引入自由权矩阵的方法,得到了系统稳定及非脆弱控制器存在的一个充分条件;然后将其转化为线性矩阵不等式(LMI)表示,通过线性矩阵不等式的可行解构造非脆弱控制器,保证了闭环系统渐近稳定且满足一定的H∞干扰抑制水平,得到的稳定化条件是依赖时滞大小且不要求时滞函数的导数信息,即适用于时滞快速变化的系统。仿真实例表明了该方法的有效性和可行性。     

基于增广Lyapunov泛函的Lurie时滞系统的绝对稳定性

对Lurie时滞系统的绝对稳定性问题进行了研究. 利用增广的Lyapunov泛函结合自由权矩阵方法, 得到了系统基于线性矩阵不等式(LMI)的时滞相关绝对稳定条件. 数值实例表明本文方法所得结果要优于现有文献中的结果.     

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.     

时变时滞Lurie非线性系统绝对稳定新判据

针对时变时滞Lurie非线性系统,应用增广Lyapunov-Krasovskii泛函结合自由权矩阵方法,研究其时滞相关绝对稳定性问题.通过保留Lyapunov-Krasovskii泛函导数中常被忽略的有用信息,充分考虑时变时滞、时滞上界及它们的差三者之间的关系,得到了具有更低保守性的基于线性矩阵不等式的时滞相关绝对稳定条件.数值实例表明,该方法得出的结果优于已有文献的结果.     

具有非线性扰动的变时滞中立型系统鲁棒稳定性新判据

研究一类具有非线性扰动的时变时滞中立型系统鲁棒稳定性问题。基于直接Lyapunov Krasovskii泛函并结合自由权矩阵方法的分析方法,建立了线性矩阵不等式(LMI)形式的离散时滞和中立时滞均相关稳定性判据。与以往方法不同,在处理泛函导数时,该方法不包含任何模型变换和涉及交叉项的处理,只是通过引入相关项自由权矩阵,充分考虑各项之间的相互关系,降低了结论的保守性。最后,利用Matlab的LMI工具箱进行了的数值仿真, 算例仿真表明所提出的判据的有效性。     

New delay-dependent conditions on robust stability and stabilisation for discrete-time systems with time-delay

This article is concerned with new robust stability conditions and robust stabilisation method for a discrete-time system with time-delay and time-varying structured uncertainties that come into state and input matrices. An improved approach to obtain new robust stability conditions is proposed. Our approach employs a generalised Lyapunov functional combined with the parameterised model transformation method and the generalised free weighting matrix method. These generalisations lead to generalised robust stability conditions that are given in terms of linear matrix inequalities. Moreover, based on new robust stability conditions, a robust stabilisation method for uncertain discrete-time systems with time-delay is given. Numerical examples compare our robust stability conditions with some existing conditions to show the effectiveness of our approach and also illustrate the improvement of our robust stabilisation method.     

Exponential stability of uncertain T-S fuzzy switched systems with time delay

This paper discusses the delay-dependent exponential stability of a class of uncertain T-S fuzzy switched systems with time delay. The method is based on Lyapunov stability theorem and free weighting matrices approach. Two illustrative examples are given to demonstrate the effectiveness of the proposed method.     

ROBUST STABILITY AND STABILIZATION OF A CLASS OF SINGULAR SYSTEMS WITH MULTIPLE TIME‐VARYING DELAYS

This paper deals with the problem of robust stability and robust stabilization for uncertain continuous singular systems with multiple time‐varying delays. The parametric uncertainty is assumed to be norm bounded. The purpose of the robust stability problem is to give conditions such that the uncertain singular system is regular, impulse free, and stable for all admissible uncertainties. The purpose of the robust stabilization problem is to design a feedback control law such that the resulting closed‐loop system is robustly stable. This problem is solved via generalized quadratic stability approach. A strict linear matrix inequality (LMI) design approach is developed. Finally, a numerical example is provided to demonstrate the application of the proposed method.     

一类非仿射系统全局镇定控制器的设计

讨论一类多输入多输出非仿射系统的全局可镇定性,其中该系统的自治系统Lyapunov稳定.利用LaSalle不变原理,得到系统全局可镇定的充分条件;基于分离原理和降阶观测器,给出了一类降阶动态输出反馈镇定控制器的设计.     

Relaxed Stability Criteria for Time-Delay Systems:A Novel Quadratic Function Convex Approximation Approach

This paper develops a quadratic function convex approximation approach to deal with the negative definite problem of the quadratic function induced by stability analysis of linear systems with time-varying delays. By introducing two adjustable parameters and two free variables, a novel convex function greater than or equal to the quadratic function is constructed, regardless of the sign of the coefficient in the quadratic term. The developed lemma can also be degenerated into the existing quadra...     

Delay-dependent Criteria for Robust Stability of Uncertain Switched Hopfield Neural Networks

This paper deals with the problem of delay-dependent robust stability for a class of switched Hopfield neural networks with time-varying structured uncertainties and time-varying delay.Some Lyapunov-Krasovskii functionals are constructed and the linear matrix inequality(LMI)approach and free weighting matrix method are employed to devise some delay-dependent stability criteria which guarantee the existence,uniqueness and global exponential stability of the equilibrium point for all admissible parametric uncertainties.By using Leihniz-Newton formula,free weighting matrices are employed to express this relationship,which implies that the new criteria are less conservative than existing ones.Some examples suggest that the proposed criteria are effective and are an improvement over previous ones.     

带有非线性扰动的时变时滞系统的稳定性准则

研究了带有非线性扰动的时变时滞系统的稳定性问题.基于时滞分割方法,提出了保守性更小的系统稳定性分析准则.利用一个自由参数将时滞区间分割为2个子区间,进而构造了含有时滞分割点状态信息和3重积分项的Lyapunov-Krasovskii泛函,并采用自由矩阵积分不等式界定泛函导数中的交叉项.基于Lyapunov稳定性定理,得到了以线性矩阵不等式描述的时滞相关型稳定性准则.数值算例表明该稳定性准则能够得到更大的时滞上界,与已有结果相比具有更小的保守性.     

Stability and harmonic analysis of a transient current limiter in distribution system

This paper proposes a methodology to investigate the stability of transient current limiter (TCL) in distribution systems. The problem is formulated to justify the performance of 12-pulse and six-pulse converter and make an unstable system to stable condition. The proposed approach explicitly deals with stability as well as minimization of total harmonic distortion. Firstly, the conventional methods of Nichols Chart, Nyquist Plot and Bode Plot used to investigate the stability of the network using TCL. In the next stage, a modified TCL circuit is inserted in the network system to make the system completely stable. A comparative analysis using Fast Fourier Transform (FFT) is shown to make the system harmonic free using MATLAB simulation. The proposed design is found to be more efficient in making the system stable and harmonic free.