“分数阶广义系统容许性的充分必要条件”一文评论

《自动化学报》39卷12期的"分数阶奇异系统容许性的充分必要条件"得到了基于线性矩阵不等式的分数阶广义系统容许性充分必要条件.本文给出一个数值反例表明文献[1]中定理1的充分条件结论并不成立, 必要条件也不准确.最后, 给出了修改正确的分数阶广义系统容许性充分必要条件.相比于文献[1]的定理1, 改进后充要条件没有保守性并去除了原文中分数阶广义系统正则性的限制要求.     

单变量系统"内模原理"的频域方法

本文用频率法讨论了单输入-单输出结构无静差系统的性质,说明了内模原理的频率表 现,给出了存在结构无静差补偿器的充要条件,提供了设计结构无静差补偿器的频率方法.     

加权非对称选择网活性和有界性分析

给出了Petri网系统的一个重要子类,即加权非对称选择网(weighted asymmetric choice net,简称WAC网)系统活性的一个充分条件和一个必要条件;同时,提出了活的有界的WAC网系统的判定条件,进而给出了WAC网活性满足单调性的充分必要条件.     

李雅普諾夫第二方法与最优控制器分析設計计问題

本文应用李雅普诺夫第二方法与贝尔曼的动态规则法,讨论了最优控制器的分析设计问题,并提出了一种对理论分析与实际计算都比较方便的序列逼近法.在第一节中,给出了最优控制器分析设计问题的一般提法与作为必要条件的贝尔曼方程.在第二节中,给出了对进一步研究所需的有关李雅普诺夫第二方法的基本结果,以便使以后的论证更为简捷.在第三节中,给出了在一般提法下分析设计问题的一般性结果,其中包括唯一性定理、贝尔曼方程的充分性、序列逼近法及其基本性质.在第四节中,研究了常系数线性系统,解决了最优控制的存在唯一性问题,文中列举了数例,以说明序列逼近法具有较快的收斂速度,并论证了这种方法的收斂速度系按指数进行的.在第五节中,研究了拟常系数线性系统,并分别对缓变系数线性系统与定常拟线性系统进行了讨论,给出了例题以说明理论结果.最后在第六节中,讨论了某些进一步推广的问题.本文所引入的方法,均直接针对综合问题而给出,因而在理论研究与实际运用上,是方便可行的.     

模糊系统的串联补偿解耦

本文提出并解决模糊关系系统的串联补偿解耦问题,给出了串联解耦补偿器的结构、实现 解耦的一个充分条件的串联补偿解耦问题的解存在的一个充要条件.     

具有干扰输入的离散广义系统有限时间控制器设计

主要研究具有干扰输入的离散线性广义系统有限时间状态稳定问题,首先讨论离散广义自治系统有限时间状态有界性问题,做为推论,给出了无外部干扰离散广义系统有限时间稳定条件,这些问题可解的充分条件以线性矩阵不等式(LMI)形式给出。     

On stability of delayed cellular neural networks with sigmoid output functions

In this paper a sufficient condition is presented to ensure the complete stability of delayed CNNs. Such a condition establishes a relation between the time delay and the parameters of the networks. Specially, for a given output function f(x) = tanh(x), we address a sufficient condition to ensure absolute convergence of system state.     

Counter-example to ‘Sufficient and necessary condition for the asymptotic stability of discrete linear interval systems’

In Jiang (1988), a condition is given which is supposedly necessary and sufficient for the stability of interval matrices in discrete-time systems. We demonstrate, via a counter-example, that the condition given is, in fact, not sufficient.     

Observer design for non-linear systems that are not uniformly observable

The observer design problem is studied for a class of single-output non-linear systems that are not necessarily uniformly observable. In the first part of this paper, the non-linear observer canonical form is generalized to the partial non-linear observer canonical form which is quite similar to the decomposition of a linear system into its observable and unobservable states. A necessary and sufficient condition is given for a non-linear system to be transformable into this canonical form by the change of coordinates. Based on this canonical form, a sufficient condition is given for the existence of observers. In the second part, a high gain observer for a class of non-linear systems that are not uniformly observable will be developed in order to relax the system structure of the partial non-linear observer canonical form. To this end, a new canonical form is proposed that generalizes the canonical form of uniform observability and a sufficient condition is provided based on the proposed canonical form.     

线性广义系统的鲁棒无源控制

考察了线性广义系统的无源性的控制问题和鲁棒无源的控制问题,使来自于物理系统的无源概念与控制理论有机结合起来.一方面,利用微分几何方法,给出了广义系统无源的充分必要条件;另一方面,将存储函数具体化,利用矩阵不等式,推出了广义系统鲁棒无源的充分条件.     

Comments on "A robust state observer scheme"

In this note, we point out that the sufficient conditions given in a recent paper to assure convergence of the proposed robust state observer are incomplete.     

基于Petri网语言的并发系统性质研究

给出Petri网弱活性（无死锁）与活性的两个语言刻画,讨论了同步合成Petri网的语言性质,基于Petri网语言,给出了判定Petri网活性的充分必要条件。同时研究了Petri网同步合成过程中活性保持问题,给出保持活性的充分必要条件。这些结果为讨论网的活性测试和控制提供了形式语言的方法。     

动态扰动解耦补偿器

本文利用极大绝对能观子系统及其对偶概念,对扰动解耦问题有解的充要条件给出了一个新的形式。对一类多输入多输出系统,给出了解耦补偿器的一般形式和稳定解耦的充要条件。     

Comments on "Robust iterative learning control design is straightforward for uncertain LTI systems satisfying the robust performance condition"

For original paper see ibid., vol.48, p.101-6 (2003). The article comments on the result of the above paper. The authors of the original paper showed that Theorem 1 is only the sufficient condition of the convergence in the sense of the L/sub 2/-norm. In this note, Theorem 1 is proved to be the not only sufficient but also necessary condition using some mathematical manipulation.     

反馈正实系统和Stalford问题

本文讨论系统的反馈正实性和Stalford问题:1)给出了系统Σ(C,A,B)为反馈正实的 新的充分必要条件;2)对Stalford问题,证明了由Chao和Stalford给出的必要条件也是充 分条件.此外还将Stalford问题推广到系统不可控的情况,并给出了易于检验的充分必要条 件.     

Comments on ‘Sufficient and necessary condition for the asymptotic stability of discrete linear interval systems’

In a recent paper by Jiang (1988), a necessary and sufficient condition for asymptotic stability of the interval matrix of discrete-time systems is presented. In this contribution it is shown that this condition is not true in general. A counter-example is given and additional remarks are made.     

一个n-可扩图的充分必要条件

本文提出了一个定理并给出了详细证明,该定理给出了n-可扩图的一个充分必要条件。     

On the simultaneous stabilization of three or more plants

In this note, the problem of the simultaneous stabilization of three multivariable plants is addressed. We consider the general case where the existence of a unit controller cannot be used as a sufficient condition to guarantee the existence of a simultaneous controller for three multivariable plants. The sufficient conditions given in this note lead to a constructive controller design to stabilize simultaneously three multivariable plants. A generalization is proposed for stabilizing simultaneously n multivariable plants     

加权T-图活性的进一步研究

本文给出加权Ｔ－图是活网的另一组充分条件，这组条件包含了Ｔｅｒｕｅｌ等对加权Ｔ－图活性分析的结果，方法简单，便于操作。Ｔｅｒｕｅｌ文中研究了加权单回路网为守恒回路时活的一个充分条件，对一般加权Ｔ图活性的判断只限于每个回路是守恒回路的情况。     

关于非线性系统非正则线性化的一个充分条件

本文得到关于仿射非线性系统非正则反馈线性问题的一个充分条件，给出并讨论了一个例子。