基于图像处理自动调焦方法的稳定性研究

本文对几种常用的图像聚焦评价函数进行了比较、研究,并在此基础上针对由于图像噪声导致评价函数不稳定,调焦重复精度不够的现象,首次提出了调焦区域选择,图像预处理,改进算法,曲线拟合四项措施结合来提高调焦重复精度.     

基于无迹卡尔曼滤波的柔性自由翻滚目标姿态估计

在进行在轨维修以及清除等任务时,需要确定航天器的姿态四元数和角速度。失效卫星常处于自由翻滚状态,通常带有柔性帆板,其运动规律相较于刚性帆板更为复杂。一方面,空间失效卫星的姿态确定常使用激光雷达、双目相机作为测量装备,其测量精度常受到光照、磁场等的影响,会对识别精度产生较大干扰。另一方面,柔性航天器的质量特性容易发生变化,导致很难对其动力学模型进行精确描述。针对柔性自由翻滚目标的状态难以获取的问题,本文提出基于无迹卡尔曼滤波的姿态估计方法,并采用神经网络补偿柔性航天器模型误差。仿真结果显示：无损卡尔曼滤波器(Unscented Kalman filter,UKF)算法对柔性航天器的姿态四元数预测误差值在10^-3范围内,角速度误差值最高0.08 rad/s,采用神经网络补偿动力学模型后对四元数的预测误差稳定在9×10^-4范围内,角速度误差稳定在1.5×10^-3范围内。结果表明,使用神经网络补偿柔性航天器动力学模型的不确定项之后,UKF对柔性自由翻滚目标的姿态估计精度满足工程要求。     

基于模糊优化模型的对空防御作战指挥决策研究

多目标模糊优化决策作为一种较新的方案选优方法,其多目标模糊决策所得的相对优属度有更大的离散性,易于决策方案选优,通过模糊优化决策建模分析,对现代防空作战打击目标决策进行比较排序,根据综合评判结果,得出最优决策方案,可为指挥员进行科学决策提供参考依据.     

Experimental Investigation on Performance of Pulse Detonation Rocket Engine Model

The PDRE test model used in these experiments utilized kerosene as the fuel, oxygen as oxidizer, and nitrogen as purge gas. The solenoid valves were employed to control intermittent supplies of kerosene, oxygen and purge gas. PDRE test model was 50 mm in inner diameter by 1.2 m long. The DDT （deflagration to detonation transition） enhancement device Shchelkin spiral was used in the test model. The effects of detonation frequency on its time-averaged thrust and specific impulse were experimentally investigated. The obtained results showes that the time-averaged thrust of PDRE test model was approximately proportional to the detonation frequency. For the detonation frequency 20 Hz, the time-averaged thrust was around 107 N, and the specific impulse was around 125 s. The nozzle experiments were conducted using PDRE test model with three traditional nozzles. The experimental results obtained demonstrated that all of those nozzles could augment the thrust and specific impulse. Among those three nozzles, the convergent nozzle had the largest increased augmentation, which was approximately 18%, under the specific condition of the experiment.     

某型飞机后机身-尾翼组合体疲劳试验随机加载谱的自动生成

 介绍了某型飞机随机载荷谱疲劳试验所采用的载荷值计算模型与算法、随机载荷状态序列与飞行顺序的生成方法、按照关键通道载荷变化量配置加载时间的方法,通过编程实现了复杂随机加载谱的自动生成以及加载时间的合理配置,提高了随机载荷谱计算的自动化程度,也提高了试验的稳定度与加载速度,为改进随机谱疲劳试验的应用技术做出了有益的尝试。     

飞机刹车盘用炭/炭复合材料新型防氧化复合涂层

 研究了一种工艺简单、成本低廉的飞机刹车盘用炭/炭复合材料防氧化复合涂层。该复合涂层由两层组成,其中内层由硼酸制备而成,外层由硼粉、炭化硼、氧化硅玻璃粉、有机硅树脂以及铝粉和铁粉制备成。恒温氧化和热震实验的结果表明：在700 ℃下空气中恒温氧化50 h后,带该涂层试样的氧化失重率只有0.08％,同时在700 ℃下空气中热循环50次后,试样的氧化失重率也只有0.12％。另外,用扫描电镜(SEM)、X射线能量分散谱(EDX)、Raman光谱和差热分析(DTA)等方法分析了涂层的防氧化机理。     

Credit Determination of Fibre Channel in Avionics Environment

Fibre channel (FC) is the main candidate architecture for “unified network”. Flow control deals with the problem in which a de- vice receives frames faster than it can process them. Credit is an important service parameter for fibre channel flow control. Configuring the credit reasonably can avoid buffer overflow in nodes. This paper derives the mathematic relationships among credit, bandwidth and message sets under real-time condition according as three main topologies of fibre channel, and proposes the credit determination and the optimal credit for typical message sets. This study is based on the features of hard real-time communications in avionics environ- ment.     

基于网络的检测数据处理系统的开发与应用

在改造检测设备基础上开发了基于网络的检测数据处理系统,并将此系统应用到产品零部件几何量检测中。应用效果表明该系统适应企业发展需求,具有广泛的推广前景和应用价值。     

基于图象处理的QR码识别

随着智能手机技术的发展和二维码技术的推广,QR码的手机识别技术的应用越来越广泛.根据QR条码图像符号的特殊性,针对QR码识别过程中手机图像采集的实际情况,应用并改进多种图像处理的方法,用C语言实现了对QR条码的译码,取得了良好的效果.     

添加微量铜对FeCoNbSiB合金非晶形成能力及磁性的影响

采用工业用硼铁为主要原料制备一种FeCoNbSiBCu大块非晶合金.采用差示扫描量热分析、X射线衍射分析、扫描电镜及能谱分析对合金的非晶形成能力进行研究.结果表明,通过添加微量Cu可以显著提高FeCoNbSiB合金玻璃形成能力,当添加Cu的原子比含量为0.5at%～0.7at%时,合金的非晶形成能力明显提高.采用振动样品磁强计对铸态样品的软磁性能进行研究.结果表明,当Cu的加入量为0.5at%时,非晶合金的软磁性能得到提高.