Identifying vital edges in Chinese air route network via memetic algorithm

Due to rapid development in the past decade, air transportation system has attracted considerable research attention from diverse communities. While most of the previous studies focused on airline networks, here we systematically explore the robustness of the Chinese air route network, and identify the vital edges which form the backbone of Chinese air transportation system. Specifically, we employ a memetic algorithm to minimize the network robustness after removing certain edges, and hence the solution of this model is the set of vital edges. Counterintuitively, our results show that the most vital edges are not necessarily the edges of the highest topological importance, for which we provide an extensive explanation from the microscope view. Our findings also offer new insights to understanding and optimizing other real-world network systems.     

Model-based robustness testing for avionics-embedded software

Robustness testing for safety-critical embedded software is still a challenge in its nascent stages. In this paper, we propose a practical methodology and implement an environment by employing model-based robustness testing for embedded software systems. It is a system-level black-box testing approach in which the fault behaviors of embedded software is triggered with the aid of modelbased fault injection by the support of an executable model-driven hardware-in-loop (HIL) testing environment. The prototype implementation of the robustness testing environment based on the proposed approach is experimentally discussed and illustrated by industrial case studies based on several avionics-embedded software systems. The results show that our proposed and implemented robustness testing method and environment are effective to find more bugs, and reduce burdens of testing engineers to enhance efficiency of testing tasks, especially for testing complex embedded systems.     

Simple and robust h-adaptive shock-capturing method for flux reconstruction framework

In this paper, a simple and robust shock-capturing method is developed for the Flux Reconstruction(FR) framework by combining the Adaptive Mesh Refinement(AMR) technique with the positivity-preserving property. The adaptive technique avoids the use of redundant meshes in smooth regions, while the positivity-preserving property makes the solver capable of providing numerical solutions with physical meaning. The compatibility of these two significant features relies on a novel limiter designed for...     

反舰导弹过载控制的随机鲁棒设计方法

基于由蒙特卡罗估计和遗传算法构成的随机鲁棒设计方法和全状态可测量的反舰导弹过载控制模型 ,提出了一种实用有效的随机鲁棒过载控制方法。由于是对直接依据系统鲁棒稳定性和鲁棒性能指标要求建立的随机鲁棒函数进行优化设计 ,所以该方法实质上是一种面向工程应用的综合设计方法。通过对某型反舰导弹的全弹道六自由度非线性时变控制系统的仿真 ,验证了该方法的有效性。     

基于局部熵差的图象匹配方法--算法及计算机仿真

传统的灰度相关匹配和基于边缘特征的匹配方法抗噪能力和抗几何失真能力较差，将信息熵的概念引入到图象匹配中，定义了图象局部熵，并由此提出一种新颖的基于局部熵差的图象匹配方法。由于图象熵反映的是图象的局部，因此基于局部熵差的图象匹配方法具有较强的抗噪能力。由于采用了分块、序贯检测及分层搜索技术，计算量大为减少，试验结果表明这是一种非常好的图像匹配方法。     

基于ESO的用户星天线跟踪指向控制技术

基于独特的非线性扩张状态观测器(ESO),提出了一种用户卫星天线跟踪指向控制系统。该系统由程序跟踪内环和自动跟踪外环组成。内环控制器由三阶ESO、线性比例微分控制律和静态解耦律组成。外环控制器为一简单的积分控制器。ESO能够在不依赖天线模型的情况下估计出系统状态和总扰动(称为扩张状态)。利用该扩张状态实现动态反馈补偿,则天线系统被简化为解耦的积分系统。基于ESO设计天线控制系统,无需精确的用户卫星天线模型。仿真结果表明,提出的天线控制系统具有较高的跟踪指向性能和对干扰和不确定性具有较强的鲁棒性。     

基于LMI的H-/H∞故障检测观测器设计

针对系统模型的不确定性、未知输入扰动,为提高对干扰鲁棒性、待检故障敏感性及降低设计的保守性,提出了一种H-/H∞故障检测观测器设计方法,通过无损procedure将非凸约束问题转化为线性矩阵不等式(LMI)约束,采用Schur补引理将H-/H∞故障检测观测器设计转化为凸优化问题的LMI表述;设计了自适应门限以减小故障检测过程中的误报、漏报率。故障检测观测器的设计是借助凸优化问题的数值计算,使设计过程便于实现。提出的算法使未知扰动的鲁棒性及待检故障的敏感性之间具有最优平衡。仿真验证表明,所提算法使残差具有快速的收敛性、较短的故障检测时间。     

武装直升机横航向增控增稳系统鲁棒性研究

武装直升机横航向增控增稳系统可看作是２输入５输出的多变量控制系统,多变量控制系统的鲁棒性可用稳定裕度作为衡量标准。利用矩阵奇异值分解的方法,计算武装直升机横航向ＳＣＡＳ的稳定裕度,来评判所设计系统的鲁棒性。该方法获得的满足鲁棒性所要求的裕度指标,为我国军用直升机飞行品质规范的修订提供了依据。     

模糊控制在光电跟瞄平台稳定控制中的应用

机载光电跟瞄系统是一个复杂的角位置随动系统,其精确模型不易建立。利用模糊控制不要求精确模型的特点,以跟瞄平台俯仰回路的稳定控制为例,设计了基本模糊控制器和自组织模糊控制器。仿真研究表明,在模型参数摄动又有多种干扰作用时,两种控制器都能进行有效地控制,特别是自组织模糊控制的稳态误差更小,计算速度更快。     

基于轨迹跟踪的飞行器大角度姿态机动物理仿真

针对空间飞行器大角度姿态机动控制具有非线性,并要求控制器具有较高的指向精度、姿态稳定度及鲁棒性等特点,应用轨迹跟踪控制算法,设计了比例微分控制器。系统采用DSP作为星载计算机、光纤陀螺作为姿态敏感器、反作用飞轮作为执行机构、系统程序采用C语言编程,利用单轴气浮仿真实验台实现了物理仿真实验。实验结果证明该控制方法能实现飞行器大角度机动控制,控制过程中能准确跟踪预定轨迹,还表现出较好的鲁棒性。