Stability Test for 2-D Continuous-Discrete Systems

Models of 2-D continuous-discrete systems are introduced, which can be used to describe some complex systems. Different from classical 2-D continuous systems or 2-D discrete systems, the asymptotic stability of the continuous-discrete systems is determined by Hurwitz-Schur stability (hybrid one) of 2-D characteristic polynomials of the systems. An algebraic algorithm with simpler test procedure for Hurwitz-Schur stability test of 2-D polynomials is developed. An example to illustrate the applications of the test approach is provided.     

2-D algebraic test for robust stability of time-delay systems with interval parameters

1. INTRODUCTION The robust stability test of time-delay systems with interval parameters is to determine whether the eigenvalues of the characteristic polynomials of the systems are located at open left half complex plane. Different from classical 1-D systems, the eigenvalues of the characteristic polynomials are infinite, classical robust stability results (Kharitonov extreme test and Edge test) for 1-D systems are not suitable for the stability test of the characteristic polynomials of…     

Two-dimensional Hurwitz-Schur stability test of linear systems with interval delays

It is difficult to determine the stability of linear systems with interval delays (LID systems) because the roots of the characteristic polynomials of the systems are continuous and vary in a complex plane with the delay. To solve the problem, this paper develops a stability test of LID systems by resorting to 2-D hybrid polynomials and 2-D Hurwitz-Schur stability. Comparing with the existing test approaches for LID systems, the proposed 2-D Hurwitz-Schur stability test is easy to apply, and can obtain closed form constraint conditions for system parameters. This paper proposes some theorems as sufficient conditions for the stability of LID systems, and also reveals that recent results about the stability test of linear systems with any delays (LAD systems) are not suitable for LID systems because they are very conservative for the stability of LID systems.     

Sufficient Conditions of Robust Schur Stability for Uncertain 2-D Polynomials

１　ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｒｅｅｘｉｓｔｓａｋｉｎｄｏｆ２Ｄｄｉｓｃｒｅｔｅｓｙｓｔｅｍｓｗｉｔｈｕｎｃｅｒｔａｉｎｐａｒａｍｅｔｅｒｓｏｒｓｕｂｊｅｃｔｔｏｒａｎｄｏｍｄｉｓｔｕｒｂａｎｃｅｓ．Ｄｉｆｆｅｒｅｎｔｆｒｏｍｕｎｃｅｒｔａｉｎ１Ｄｐｏｌｙｎｏｍｉａｌｓ，ｔｈｅｐａｒａｍｅｔｅｒｓｐａｃｅｏｆｔｈｅｕｎｃｅｒｔａｉｎ２Ｄｐｏｌｙｎｏｍｉａｌｓｉｓｏｆ（Ｍ＋１）×（Ｎ＋１）ｄｉｍｅｎｓｉｏｎｓａｔｍｏｓｔ．ＴｈｏｕｇｈｓｏｍｅｒｅｓｕｌｔｓａｂｏｕｔｔｈｅｒｏｂｕｓｔＨ…     

Characteristic polynomial assignment in F-M model Ⅱ of 2-D systems

The problems of characteristic polynomial assignment in Fornasini-Marchesini (F-M) model Ⅱ of 2-D systems are investigated. The corresponding closed-loop systems described by F-M model Ⅱ are obtained via the state feedback.Using the algebraic geometry method, the characteristic polynomial assignment in the closed-loop systems is discussed. In terms of the theory of algebraic geometry, the problem of characteristic polynomial assignment is transferred to the one whether a rational mapping is onto. Sufficient conditions for almost arbitrary assignment coefficients of characteristic polynomial in F-M model Ⅱ of 2-D systems via state feedback are derived, and they are available for multi-input cases. It also has been shown that this method can be applied to assign the characteristic polynomial with output feedback. The sufficient conditions for almost arbitrary assignment coefficients of characteristic polynomial of multi-input 2-D systems described by F-M model Ⅱ with output feedback are established.     

Improved 2-D Stability Margin Test for 2-D Discrete Systems

１ＩｎｔｒｏｄｕｃｔｉｏｎＳｉｎｃｅｓｔａｂｉｌｉｔｙｍａｒｇｉｎｄｅｆｉｎｉｔｉｏｎｓａｎｄｔｅｓｔｓｆｏｒ２－Ｄｄｉｓｃｒｅｔｅｓｙｓｔｅｍｓｗｅｒｅｐｒｏｐｏｓｅｄ［１，２］，ｓｏｍｅｉｍｐｒｏｖｅｍｅｎｔｓｈａｖｅｂｅｅｎｍａｄｅ［３，４］．...     

Characteristic Polynomial Assignment in 2-D System

CONTROL THEORY AND APPLICATION1. IWTSODUCTIONTwo-dimensional (2-D) systems have mad applications such as 2-D digital Kalman filtering, image processing,etc., and have been studied extensively during the past two decades [1, 2]. The characteristic polynomialassignment problem for 2-D systems is one of the most important problems in the research of 2-D systems,and has been considered by many authors. In reference 13], the author has presellt a method for coefficielltassignmellt …     

2-D连续-离散系统的平衡模型降阶

基于局部能达性与局部能观性的分析给出2-D连续-离散系统状态空间模型的平衡实现,这一实现的第i个状态分量的重要性由系统的能达、能观阵的第i个对角元素所度量,去掉平衡实现系统弱能达、弱能观的部分,从而得到2-D连续-离散系统的模型降阶。所给示例表明,该方法具有良好的降阶效果。     

一种改进的二维直方图的图像阈值分割方法

图像分割是图像处理的重要部分。它是图像描述和图像识别等更深层次图像处理的基础步骤之一。对基于传统的二维灰度直方图的阈值分割方法作了分析,针对其区域划分的缺陷和运算速度慢的缺点,改进了传统的二维直方图,并在此基础上提出了一种新的根据最大类间方差原则的阈值图像分割方法,并进行了仿真实验。实验的结果表明,所提出的改进方法是有效的,该算法的分割效果较好,运算速度也得到了提高。     

基于2-D系统理论的变初始条件离散系统的迭代学习控制

对于具有重复运动特性的系统，迭代学习控制是一种简单有效的控制方法。为便于实时应用，所有迭代学习控制方案的设计必须在离散时间域进行。初始状态问题是学习控制设计中遇到的一个重要问题。针对具有变初始状态的离散时间系统，利用2-D线性连续．离散型系统理论设计了闭环迭代学习控制器，并给出了保证控制器收敛的充分必要条件。仿真结果证明了该方案的有效性。     

圆周合成孔径雷达投影共焦三维成像算法

针对圆周合成孔径雷达成像模式下应用共焦三维成像算法成像效率低的问题,提出了投影共焦三维成像算法.该算法利用圆周合成孔径雷达成像模式下成像区域较小时高度向与水平面相对较弱的耦舍性,将共焦三维成像算法中的三维空变滤波转化为水平面内的二雏空变滤波和高度向时域平移,从而化三维成像的三雏处理为二维处理,以提高算法的成像效率.通过引进天线远场条件作为成像区域较小的判定标准,定量分析了算法的适用条件.仿真结果验证了该算法较高的成像效率及算法适用条件的有效性.     

复杂背景下的二维检测研究

由于雷达检测背景的复杂和起伏 ,经典CFAR检测不能保持稳定的检测性能。利用噪声和目标在距离 -多普勒二维平面上的信息构成特殊的二维窗 ,异常值剔除后进行二维窗的检测统计量计算。实验中 ,各种经典CFAR检测的稳定性和检测性能得到了不同程度的提高 ,本文提出的混合检测方式获得了最佳的检测性能。     

两坐标雷达融合定位算法

传统的两坐标雷达目标定位算法需通过迭代求取目标位置估计,不仅计算量大,而且有可能得到局部最优解,甚至无效解。提出了一种组网融合定位算法,利用数据融合技术进行目标定位,回避了费时的迭代搜索,同时保证了估值的有效性。仿真实验验证了该方法的有效性。     

四维可视化多目标寻优方法及其在T型滤波器设计中的应用

针对多目标优化设计中存在寻优空间小、计算难度大等问题,提出4雏可视化寻优方法,将颜色作为第4变量引入3维坐标系中,分别用三维坐标表示待求自变量,用三维空间诸点的颜色表示目标函数的值.视图中多个切片的同色线集成为空间等值域,获得清晰的4维显性可视化效果,并据图中的交域颜色分布实现多目标寻优.以对逆变器的非对称无源T型低通滤波器进行优化设计为例对该方法进行了详细说明和论证,在扩大的寻优范围内,目标函数的分布状态清晰可见,有效地提高了优化解的稳定性.本方法表明:在寻优过程中应充分考虑目标函数对子变量的敏感性.提供了数学证明,介绍了使用本方法的设计准则,以及用于定量比对的实验数据.     

双应力恒加寿命试验下相依竞争失效模型的统计分析

针对传统加速寿命试验仅考虑单一应力且假定产品各失效机理之间独立的问题,首先结合自适应逐步Ⅱ型混合截尾(adaptive type-Ⅱ progressively hybrid censored scheme, AT-Ⅱ PHCS)寿命试验,建立AT-Ⅱ PHCS双应力恒加寿命试验。其次,利用Marshall-Olkin二维Gompertz (Marshall-Olkin bivariate Gompertz, MOBG)分布构建产品失效机理间相依关系。然后,基于AT-Ⅱ PHCS双应力加速寿命试验下相依竞争失效数据,利用极大似然理论,计算了参数的极大似然估计(maximum likelihood estimation, MLE),采用渐近似然理论和Bootstrap抽样方法构建参数的置信区间(confidence interval, CI)。最后,结合一个实例对构建的相依竞争失效模型进行了算例验证,结果表明其具有很好的统计推断性能。     

双应力恒加寿命试验下相依竞争失效模型的统计分析

针对传统加速寿命试验仅考虑单一应力且假定产品各失效机理之间独立的问题,首先结合自适应逐步Ⅱ型混合截尾(adaptive type-Ⅱ progressively hybrid censored scheme, AT-Ⅱ PHCS)寿命试验,建立AT-Ⅱ PHCS双应力恒加寿命试验。其次,利用Marshall-Olkin二维Gompertz (Marshall-Olkin bivariate Gompertz, MOBG)分布构建产品失效机理间相依关系。然后,基于AT-Ⅱ PHCS双应力加速寿命试验下相依竞争失效数据,利用极大似然理论,计算了参数的极大似然估计(maximum likelihood estimation, MLE),采用渐近似然理论和Bootstrap抽样方法构建参数的置信区间(confidence interval, CI)。最后,结合一个实例对构建的相依竞争失效模型进行了算例验证,结果表明其具有很好的统计推断性能。     

离散线性区间系统的分支稳定性

研究了离散区间系统的一种特殊形式的稳定性 ,即分支稳定性。分别给出了离散区间系统分支渐近稳定性和指数分支渐近稳定性的定义。证明了离散区间系统是分支渐近稳定的 ,且仅当系统矩阵在每一时刻都将满足一个约束条件的系统状态向量变换成满足另一个约束的向量。由此利用不等式的性质分别给出了离散区间系统分支渐近稳定和指数分支渐近稳定的充要条件     

Multiple targets vector miss distance measurement accuracy based on 2-D assignment algorithms

An extension of 2-D assignment approach is proposed for measurement-to-target association for improving multiple targets vector miss distance measurement accuracy. When the multiple targets move so closely, the measurements can not be fully resolved due to finite resolution. The proposed method adopts an auction algorithm to compute the feasible measurement-to-target assignment with unresolved measurements for solving this 2-D assignment problem. Computer simulation results demonstrate the effectiveness and feasibility of this method.     

基于二维混合模型的鲁棒迭代学习控制设计

针对一类正则线性不确定系统,提出一种基于连续/离散二维混合模型的迭代学习控制设计方法。首先,通过独立地考虑迭代学习控制系统连续的控制行为与离散的学习行为,建立迭代学习控制系统的连续/离散二维混合模型,将迭代学习控制器设计问题转化为一类连续/离散二维系统的状态反馈控制问题。然后应用二维连续/离散系统方法,获得迭代学习控制系统稳定性条件。最后根据稳定性条件,利用线性矩阵不等式方法,求得迭代学习控制器参数,它通过Matlab工具箱可以方便的获得。与现有方法相比,所提出的迭代学习控制器利用了输出误差以及状态变化的信息来修正当前的控制,因而设计方法更加符合其本质特征,具有简单实用、直观明了的特点。数值仿真实例验证了所提方法的有效性。     

新的空时二维谱估计信号模型

针对现有空时二维谱估计算法在信号数增大时均不同程度出现性能上的恶化直至失败的问题,总结了目前通用的空时二维谱估计信号模型,提出了“时域副流形”的概念及相应的信号处理方法。该算法通过时域投影对信号进行预处理,先从时域上对信号进行粗分,从而以较小的代价换取大信号数情况下算法性能的改善。理论分析与仿真结果证明了算法的有效性。