Robust image-based coordinated control for spacecraft formation flying

This paper addresses a coordinated control problem for Spacecraft Formation Flying (SFF). The distributed followers are required to track and synchronize with the leader spacecraft. By using the feature points in the two-dimensional image space, an integrated 6-degree-of-freedom dynamic model is formulated for spacecraft relative motion. Without sophisticated three-dimensional reconstruction, image features are directly utilized for the controller design. The proposed image-based controller can drive the follower spacecraft in the desired configuration with respect to the leader when the real-time captured images match their reference counterparts. To improve the precision of the formation configuration, the proposed controller employs a coordinated term to reduce the relative distance errors between followers. The uncertainties in the system dynamics are handled by integrating the adaptive technique into the controller, which increases the robustness of the SFF system. The closed-loop system stability is analyzed using the Lyapunov method and algebraic graph theory. A numerical simulation for a given SFF scenario is performed to evaluate the performance of the controller.     

求解气动弹性系统动态特性的一种准确方法

本文提出一种求解气动弹性系统动态特性的准确方法——正交搜索法,它利用复变函数中解析函数保角映射的特性,沿复频率s的实部和虚部交譬搜索,逐步达到所求复方程的根。该算法能在计算机上实现,直观、简便、实用。     

机载火控系统智能检修设备的设计

介绍了基于PC的机载火控系统智能检修设备的设计思想,重点讨论了检修设备的硬软件实现方法.在软件部分阐述了利用VC控件MSComm编程实现串口通信的方法.系统精度和自动化程度高,具有良好的通用性,可方便地推广应用到新型机载火控系统上.     

基于HyPneu的某型机襟翼系统建模与仿真计算

基于专用流体仿真软件——HyPneu，阐述了对某型飞机襟翼收放系统进行可视化建模仿真计算的全过程。并在此基础上提出了流体仿真的基本流程以及需要注意的方面。     

Mission decision-making method of multi-aircraft cooperatively attacking multi-target based on game theoretic framework

Coordinated mission decision-making is one of the core steps to effectively exploit the capabilities of cooperative attack of multiple aircrafts. However, the situational assessment is an essential base to realize the mission decision-making. Therefore, in this paper, we develop a mission decision-making method of multi-aircraft cooperatively attacking multi-target based on situational assessment. We have studied the situational assessment mathematical model based on the Dempster-Shafer (D-S) evidence theory and the mission decision-making mathematical model based on the game theory. The proposed mission decision-making method of antagonized airfight is validated by some simulation examples of a swarm of unmanned combat aerial vehicles (UCAVs) that carry out the mission of the suppressing of enemy air defenses (SEAD).     

燃烧条件下凝胶自燃推进剂雾化特性试验研究

为了研究凝胶自燃推进剂的雾化特性及敏感因素,在单互击式喷嘴矩形燃烧室内进行了凝胶一甲基肼/四氧化二氮(MMH/NTO)喷雾燃烧过程可视化试验,采用光源后置消光法湮灭火焰自然辐射发光,采用彩色高速摄影获取了燃烧条件下的高质量雾场阴影图像,通过图像处理,有效提取了雾场的雾化锥角、破碎长度、液丝直径及液丝运动速度,分析了撞击角、射流速度和动量比的影响。结果表明,凝胶MMH/NTO稳态燃烧时可观察到液膜、贯穿视场的液丝和红棕色NO_2气体,推进剂混合燃烧不充分;撞击角从75°增大到105°,凝胶MMH/NTO撞击后的破碎长度、液丝直径减小,视场内可视红棕色NO_2气体变少,撞击角为105°时,推进剂会附着在喷注面上,从而影响液膜横向铺展,雾化锥角反而最小,建议撞击角选取90°。燃料射流速度从23m/s增大到45m/s,凝胶MMH/NTO撞击后的雾化锥角及液丝运动速度增大,破碎长度及液丝直径减小,雾化模式发生改变。动量比从1.04增大到1.52,凝胶MMH/NTO撞击后的雾化锥角及液丝运动速度增大,视场内红棕色NO_2气体变少。故一定量程内增加撞击角、射流速度、动量比有助于凝胶MMH/NTO推进剂混合燃烧。     

一种基于星表特征直线匹配的着陆器位姿估计算法

针对深空探测星际着陆过程中的自主导航问题,提出一种基于星表特征直线的着陆器位姿估计算法。该算法首先采用EDLine算法对着陆过程中所拍摄的图像进行特征直线提取;其次根据直线局部特征对特征直线进行匹配;之后利用至少3对已匹配的特征直线,建立关于着陆器位姿的几何约束方程;然后根据奇异值分解法得到着陆器位姿的候选解;最终通过最小二乘法从候选解中选取着陆器位置、姿态的唯一解。仿真结果表明:该算法可以快速估计着陆器位姿,且在高度为2 000 m时位置误差小于2 m、姿态误差小于0.10°。     

一种面向服务的业务过程建模语言

通过对现有业务过程建模语言的分析指出了其对面向服务支持的不足,以可视化过程建模语言VPML(Visual Process Modeling Language)为基础,提出了一种面向服务的可视化过程建模语言VPML-S,并提出了该语言的概念设计框架,简述了其通用的建模元素;使用UML类图设计了该语言的元模型,在此基础上建立了语言的形式化模型;分析和评估了VPML-S中的服务元素所提供的将活动映射为Web服务的面向服务功能,嵌入子过程元素所提供的多个业务过程之间的复用机制,管道元素所提供的多个业务过程的协作机制以及VPML-S和其它语言所建立的业务过程模型的互操作支持机制;评述了VPML-S的可视化图符替换、元模型扩展机制;最后通过一个网上购物流程实例说明VPML-S为面向服务的环境下的业务过程复用、协作和互操作提供了有效的支撑.      

基于SCPSO算法的MCPC雷达波形优化设计

针对多载波互补相位编码MCPC信号在应用中存在包络起伏大等问题,结合混沌映射和自适应混沌粒子群SCPSO算法提出了一种优化设计。设计将编码信号的主瓣峰值与最大旁瓣值比PSLR作为单独的评判依据,结合混沌序列类随机的性质对混沌序列进行两级筛选,得到自相关函数旁瓣较低的混沌编码序列组。考虑到MCPC信号结构的特点,应用SCPSO算法调整子载波权重因子来优化信号的PMEPR。仿真分析表明,优化设计能在保证MCPC信号优良自相关特性的情况下,有效降低信号的包络起伏。     

G-凸空间上的广义G-S-KKM定理与应用

在G-凸空间上建立广义G-S-KKM映射并得到一些定理.