非线性状态误差反馈控制律—NLSEF

给出一种独立于对象数学描述的新型状态误差反馈控制律－ＮＬＳＥＦ方案。跟踪－微分器能够很好地估计出不确定对象的“扩张状态”，从而为实现“状态反馈”和“模型，外扰补偿”提供了可能性。这种“模型补偿”实质上等价于非线性系统的“反馈线性化”。在这个方案中不必为消除外扰引起的稳态误差而采“积分器”，大量计算机仿真实验表明，本文给出的控制律－ＮＬＳＥＦ具有很好的“适应性”和很强的“鲁棒性”。  

Determining the Epipolar Geometry and its Uncertainty: A Review

Two images of a single scene/object are related by the epipolar geometry, which can be described by a 3×3 singular matrix called the essential matrix if images' internal parameters are known, or the fundamental matrix otherwise. It captures all geometric information contained in two images, and its determination is very important in many applications such as scene modeling and vehicle navigation. This paper gives an introduction to the epipolar geometry, and provides a complete review of the current techniques for estimating the fundamental matrix and its uncertainty. A well-founded measure is proposed to compare these techniques. Projective reconstruction is also reviewed. The software which we have developed for this review is available on the Internet.  

系统鲁棒性的若干问题——背景、现状与挑战*

本文进行系统鲁棒性分析的综述,全文分四节,第1节是引言,给出了问题的缘由、现代鲁棒分析的提法与一些基本概念,第2节介绍并评论了多项式代数方法的一些突破性进展,如Kharitonov定理、棱边定理与其它一些结果,在第3节中,对稳定矩阵的摄动界分析和基于状态空间描述与李亚普诺夫方法的鲁棒性的讨论作了介绍,最后在第4节中论述了基于输入输出描述的方法和H~∞方法。  

The Development and Comparison of Robust Methods for Estimating the Fundamental Matrix

This paper has two goals. The first is to develop a variety of robust methods for the computation of the Fundamental Matrix, the calibration-free representation of camera motion. The methods are drawn from the principal categories of robust estimators, viz. case deletion diagnostics, M-estimators and random sampling, and the paper develops the theory required to apply them to non-linear orthogonal regression problems. Although a considerable amount of interest has focussed on the application of robust estimation in computer vision, the relative merits of the many individual methods are unknown, leaving the potential practitioner to guess at their value. The second goal is therefore to compare and judge the methods.Comparative tests are carried out using correspondences generated both synthetically in a statistically controlled fashion and from feature matching in real imagery. In contrast with previously reported methods the goodness of fit to the synthetic observations is judged not in terms of the fit to the observations per se but in terms of fit to the ground truth. A variety of error measures are examined. The experiments allow a statistically satisfying and quasi-optimal method to be synthesized, which is shown to be stable with up to 50 percent outlier contamination, and may still be used if there are more than 50 percent outliers. Performance bounds are established for the method, and a variety of robust methods to estimate the standard deviation of the error and covariance matrix of the parameters are examined.The results of the comparison have broad applicability to vision algorithms where the input data are corrupted not only by noise but also by gross outliers.  

不确定系统的鲁棒输出反馈区域极点配置

对一类具有范数有界参数不确定性的线性系统, 研究了使得闭环系统的所有极点均位于一给定圆盘中的输出反馈控制器设计问题. 采用线性矩阵不等式处理方法, 证明了该问题等价于一个线性矩阵不等式的可解性问题, 并利用该线性矩阵不等式的可行解给出了输出反馈控制器的构造方法. 所提出的方法既可应用到连续系统, 也可应用到离散系统.  

动态区间系统的鲁棒稳定性

研究了动态连续间系统和离散区间系统的鲁棒稳定性问题，在给出了区间系统的一种等价描述之后，利用Lyapunov方法和RIccati方程方法，分别得到了连续间我系统和离散区间系统鲁棒稳定的充分条件，最后的数值例子说明本文的结果不仅保守性小，而且计算简单。  

Experience with approximate reliability-based optimization methods

Traditional reliability-based design optimization (RBDO) requires a double loop iteration process. The inner optimization loop is to find the most probable point (MPP) and the outer is the regular optimization loop to optimize the RBDO problem with reliability objectives or constraints. It is well known that the computation can be prohibitive when the associated function evaluation is expensive. As a result, many approximate RBDO methods, which convert the double loop to a single loop, have been developed. In this work, several approximate RBDO methods are coded, discussed, and tested against a double loop algorithm through four design problems.  

基于主动滑模控制的一类不确定混沌系统的同步

讨论了一类不确定混沌系统的同步问题。基于主动控制思想,提出了一种新的主动滑模控制策略,使得从任意初始条件出发的不确定混沌系统在有限时间内趋近滑模面;通过一种新颖的虚拟反馈控制,得到了设计鲁棒滑模面的一个充分条件,较好地实现了响应系统与驱动系统的完全同步,确保了不确定混沌系统同步的鲁棒稳定性。该控制器适用于一般的混沌系统。以Lü混沌系统为例进行了仿真验证,仿真结果表明,该控制方法可以实现较快的混沌同步,且同步的鲁棒稳定性良好。  

Robust design with arbitrary distributions using Gauss-type quadrature formula

In this paper, we present the Gauss-type quadrature formula as a rigorous method for statistical moment estimation involving arbitrary input distributions and further extend its use to robust design optimization. The mathematical background of the Gauss-type quadrature formula is introduced and its relation with other methods such as design of experiments (DOE) and point estimate method (PEM) is discussed. Methods for constructing one dimensional Gauss-type quadrature formula are summarized and the insights are provided. To improve the efficiency of using it for robust design optimization, a semi-analytic design sensitivity analysis with respect to the statistical moments is proposed for two different multi-dimensional integration methods, the tensor product quadrature (TPQ) formula and the univariate dimension reduction (UDR) method. Through several examples, it is shown that the Gauss-type quadrature formula can be effectively used in robust design involving various non-normal distributions. The proposed design sensitivity analysis significantly reduces the number of function calls of robust optimization using the TPQ formulae, while using the UDR method, the savings of function calls are observed only in limited situations.