具有结构式和非结构式摄动的反馈系统的鲁棒稳定性

具有结构式和非结构式摄动的反馈系统的鲁棒稳定性田玉平（东南大学自动化研究所·南京，２１００１８）１９１ｔ不确定线性系统的有棒性分析是现代控制理论中的重要课题之一．目前的研究主要集中在以下两类不确定性上．第一类是所谓的非结构式不确定性，一般用有界范数来...     

极点配置在指定区域的一种鲁棒性分析方法

本文给出当系统的极点在由复数李雅普诺夫方程所确定的复平面内一个指定区域内，则该系统的极点必定在一个更“紧缩”的确定的区域内，分别人系统设计考虑动态响应和参数扰动的鲁棒性出发，提出了设置两个指定区域，并给出由奇异值所决定的摄动矩阵的模界。     

参数平面法及其在飞机鲁棒控制系统设计中的应用

本文提出一种新的参数平面法,它基于系统矩阵,直接将特征平面上的特征根分布要求域与参数平面上的可取参数域对应起来,可方便地选定设计参数,使系统对参数的大范围变化具有鲁棒性。本文采用这一方法,以 MIL—F—8785B军用规范为准则,对某型歼击机进行鲁棒控制器的设计,用结构简单、参数固定的控制器使飞机对气动参数的变化具有较强的鲁棒性。     

基于单幅图像的人脸三维姿态估计

针对单张人像的三维姿态计算，结合面貌测量和射影几何的理论提出了一种方法：首先在人面部的平面区域内，选取眼角点，口角点，鼻翼点建立人脸模型;然后根据人脸平面上两个相互垂直的特征线投影到照片上的灭点位置，求出人脸平面的旋转方向。该方法特征点易于标定，且无需任何的辅助设备和先验知识，具有一定的实用性。     

不确定T-S 模型的D -域极点约束鲁棒控制

对于具有两类不确定性的Takagi-Sugeno模糊非线性模型,运用二次稳定思想,提出使闭环系统的极点在各种允许的不确定性下始终在复平面上某个二次矩阵不等式区域D中的一个充分条件.基于这一条件和并行分布补偿技术,用线性矩阵不等式方法,设计全局鲁棒D-稳定控制器.最后通过质量弹簧阻尼系统给出了所述设计方法的仿真示例.     

一种新的中立型延时系统不稳定特征根的数值方法

针对中立型延时系统超越特征方程的特点,提出了计算其不稳定特征根的数值方法.首先分析了系统具有有限个不稳定特征根的条件及其在复平面上的范围.并结合特征根的对称性.缩小计算范围;然后对缩小后的区域进行网格划分,根据函数局部极小值原理并结合几何搜索的方式得到不稳定特征根的近似值,作为非线性无约束优化方法fsolve的初值,进而得到不稳定特征根的数值解;最后通过计算实例验证了所提方法的有效性.     

一类不确定性时滞关联大系统的分散鲁棒稳定控制器设计

对一类满足匹配条件的不确定性关联大系统，设计了基于一组线性矩阵不等式（LMI）有解的系统状态反馈镇定的充分条件。本文采用了实对称矩阵集合的最小上界定理，并对设计参数进行优化处理，从而使得所设计的控制器具有较小反馈增益。同时系统的不确定性采用区间矩阵表示，因此该设计方法具有很好的普遍性。最后给出的仿真实例说明了该方法的有效性。     

三维花粉图像局部二值模式提取方法

针对二维特征无法描述三维花粉图像的内部结构和三维空间像素关联问题,提出一种三维花粉图像局部二值特征提取方法.首先选取特征平面用于标记局部灰度变化方向;然后计算中心像素邻域上的局部灰度方向向量,并根据局部灰度方向向量计算最优特征平面;再在最优特征平面上计算该像素的局部纹理特征构建特征矩阵;最后提取该矩阵的统计直方图描述子作为鉴别特征,用于三维花粉图像分类识别.通过在欧洲Confocal和Pollenmonitor这2个标准花粉库,以及中国境内实时采集花粉图像库CHMonitor上的实验结果表明,该方法的识别率最高可以超过95%,同时对于花粉图像的比例和姿态变化具有较好的鲁棒性,和传统方法相比具有更好的识别效果.     

基于位平面理论和奇异值分解的鲁棒零水印算法

针对灰度图像空域算法中水印鲁棒性较差的问题,提出了一种快速、鲁棒性强的零水印算法,并将该算法用于以数字图像为载体的信息隐藏,以实现水印信息的提取和认证。首先利用位平面(BP)理论将图像解析为不同的位平面层次,构造无权值的位平面矩阵,结合各位平面非零值个数生成图像的特征矩阵;然后对特征矩阵分块操作,利用奇异值分解(SVD)生成块最大奇异值矩阵,并通过对生成矩阵二维混沌加密得到注册零水印信息。仿真实验表明,所提算法具有较强的鲁棒性,在同类算法中对抗椒盐噪声攻击的性能提高了6%,对抗常见混合攻击的性能提高了12%。     

基于Kinect的环境平面特征提取与重构

针对三维场景物体特征识别过程中数据量大、算法复杂等问题,提出一种基于Kinect的环境平面特征提取与重构算法。首先,针对场景的点云分割,采用融合场景几何信息和颜色信息的随机采样一致性(RANSAC)算法,综合二者分割优势,克服几何特征分割过程中分割不足或者过分割,提高分割精度;其次,根据投影变换原理推导出相应的三维坐标变换矩阵,指导分割后独立区域内的三维平面特征信息到二维空间映射,利用凸包概念搜索物体边界信息,实现二维空间的轮廓点提取;最后,通过旋转逆变换,恢复轮廓点的三维信息,完成环境特征重构。采用3组场景数据验证所提算法,实验结果表明,所提算法分割较精确,不容易产生过分割的情况,对不同形状特征的物体,具有较好的重构效果。     

Robust matrix 𝒟U‐stability analysis

In this paper, the problem of robust matrix root‐clustering is addressed. The studied matrices are subject to both polytopic and unstructured uncertainties. An original point is the large choice of clustering regions enabled by the proposed approach since these regions can be unions of possibly disjoint and non‐symmetric subregions of the complex plane. The precise purpose is, considering a specified polytope, to determine the greatest robustness bound on the unstructured uncertainty such that robust matrix root‐clustering is ensured. To reduce conservatism in the derivation of the bound, the reasoning relies on a framework based upon parameter‐dependent Lyapunov functions. The bound value is computed by solving an ?? ?? ? problem. Copyright © 2003 John Wiley & Sons, Ltd.     

Perturbation bounds for root-clustering of linear systems in aspecified second order subregion

Sufficient bounds for structured and unstructured uncertainties for root-clustering in a specified second order subregion of the complex plane, for both continuous-time and discrete-time systems, are given using the generalized Lyapunov theory. Furthermore, for unstructured uncertainties, a still less conservative result is obtained by shifting the center or focus of the subregion along the real axis to the origin and by applying root-clustering to the “shifted eigenvalue” system matrix, which is obtained by shifting the eigenvalues of the system matrix correspondingly     

Common Lyapunov function approach to matrix root clustering

This paper proposes an alternative route to the matrix root clustering problem, which enables to use a result on the common Lyapunov function for solving the problem efficiently. A necessary and sufficient condition is obtained in terms of the existence of a common positive definite solution to a set of Lyapunov inequalities for eigenvalues of a matrix to lie in a prescribed subregion of the complex plane. Applications to root clustering in sector regions are shown for illustration.     

Pole assignment of linear uncertain systems in a sector via aLyapunov-type approach

The problem of designing robust control laws, in performance and in stability, for uncertain linear systems is considered. Performances are taken into account using root clustering of the closed-loop dynamic matrix in a sector of the complex plane. A synthesis procedure, based on a sufficient condition for quadratic stabilization and root clustering, such as stabilizability, is given, using an auxiliary convex problem. The results are illustrated by a significant example from the literature     

Robust pole clustering in a good ride quality region of aircraft for matrices with structured uncertainties

This paper presents a general analysis of robust pole clustering in a good ride quality region (GRQR) of aircraft for matrices with structured uncertainties. This region is an intersection of a ring and a horizontal strip, located in the left half-plane, which is a specific non-Ω-transformable region providing good ride quality of aircraft. The paper applies the Rayleigh principle along the norm theory to analyze robust pole clustering within this region since the generalized Lyapunov theory is not valid for non-Ω-transformable regions. Concerned uncertainties are structured/parametric uncertainties, including interval matrices. The results are useful for robust control analysis and design, especially, of robust good ride quality of aircraft, shuttles, vehicles and space station, as well as some industrial systems. An example of the F-16 dynamics for which GRQR is suitable is included to illustrate the results.     

Extending Kharitonov's theorem to eigenvalues clustering in subregions of the complex plane

Sufficient conditions are developed for root clustering of a polynomial in a transformable region when each of the polynomial coefficients takes an arbitrary but fixed value within a specified closed interval. The conditions are in terms of the Kronecker products or the bialternate products. The sufficient conditions are then applied to different subregions in the complex plane. The work of Barmish (1984) on the invariance of the strict Hurwitz property for interval polynomials with perturbed coefficients is extended to root clustering in a region.     

Linear matrix equations and root clustering

Given A ε ?^{n + n} and ? ? ?, we search for a criterion assuring that the spectrum of A is clustered in ?, σ(A)? ? One approach to root clustering is the linear matrix equation, whose half plane version dates back to Lyapunov. The existing literature deals with an algebraic region defined by a single polynomial. In this paper, we construct a novel linear matrix equation related to the intersection of algebraic regions. This considerably enlarges the family of regions with root clustering criteria.     

Parameter bounds for root clustering of uncertain matrices

This paper deals with robust root-clustering in a region of order one or two of the complex plane. We consider continuous or discrete linear state-space models with unstructured and structured perturbations. Some bounds on allowable perturbations that maintain the eigenvalues of a system matrix in a desired region are derived. These bounds are shown to be less conservative than existing ones.     

Bounds on generalized structured singular values via the Perron root of matrix majorants

The purpose of this paper is to present several bounds upon the structured singular value. We first adopt a generalized notion of the structured singular value which is useful for problems where uncertainties are assumed to be bounded in an l_p-induced matrix norm. Two different type of bounds, in terms of Perron root and interaction parameters respectively, are given for the new structured singular value and their relations are discussed. These bounds are useful in that they are easy to compute and may be further analyzed to provide insights useful in design.     

结构型摄动多项式族的不变惯性

给了一个结构型摄动多项式族以及复平面上的稳定性区域，是否这个族的这区域的内部，边界与外部有着不变的根的数目？这是所谓的不变惯性问题，本文将予回答，在否定的情况下，我们要给出方法去把族分割为一些族使对每一子族而言它有着各自不变的惯性。