激光冲击强化对加力燃烧室火焰探测器焊缝的影响

为了研究激光冲击强化（LSP）后加力燃烧室火焰探测器焊缝位置异常开裂原因,采用X射线衍射方法和金相方法对激光冲击强化效果进行分析,并利用扫描电子显微镜对断口进行了观察。在Abaqus有限元分析软件中建立了与观察到的焊缝缺陷相似的有限元模型,对焊缝缺陷的LSP处理及冲击波传播过程进行了模拟分析。试验结果表明：具有较好材料完整性的区域经LSP处理后,表面会预置较大残余压应力,同时表面金属晶粒得到细化,疲劳裂纹会在焊缝缺陷位置萌生和扩展。有限元分析结果表明：存在分层缺陷的焊缝经LSP强化后,冲击波会在分层缺陷处产生反射,造成分层位置发生开裂,形成裂纹源造成疲劳开裂。根据试验和仿真分析结果,为提升火焰探测器焊缝激光冲击抗疲劳效果,建议优化焊接工艺,提高焊接质量。     

功能分析与失效物理结合的可靠性预计方法

 可靠性预计是产品设计、研发过程中的重要工作,全面准确的可靠性预计可以评价产品的可靠性水平,也可以为设计提供信息,指导设计。全面分析总结当前电子设备可靠性预计相关技术方法,以当前基于失效物理(POF)技术的系统可靠性预计方法中,并未考虑产品功能组成关系的缺陷为突破点,建立了一种以失效物理分析为基础,综合考虑电路功能组成关系的电子设备可靠性预计方法。该方法从电路功能出发,通过灵敏度仿真和主成分分析两种方法,确定对电路性能起主要影响的关键单元,再通过失效物理分析或统计规律明确单元的失效概率分布,通过混合分布获得系统的分布,得到系统可靠性指标。最后以某航空机电产品的电源电路为案例,对本预计方法进行验证。     

多路径效应对低空箔条云RCS的影响

应用已有的理论计算公式,分析研究了多路径效应对低空箔条云RCS测量的影响,对低空箔条云RCS测量试验中出现的数据变化给出了合理的解释,提高了试验数据的可信度.     

小型自动茶叶包装机设计

针对当前市场上流行的茶叶包装机价格昂贵、只适用于大型流水线作业,无法满足小微企业中的问题,本文设计了一种采用单片机控制为核心的小型电动茶叶包装机,可以根据客户需求完成10克以下的小克重茶叶包装,包装操作方便,价格低廉,为小微茶企的发展起到了推动作用。     

高速旋板泵旋板动压支承设计

旋板端部与定子内表面间的摩擦副设计是高速旋板泵设计的技术关键。本文把流体动力润滑理论用于高速旋板泵的设计,着重探索旋板动压支承的设计,提出了一种设计方法。算例结果表明,本文的设计方法可使动压支承尺寸与泵总体尺寸相匹配。     

Use of land＇s cooperative object to estimate UAV＇s pose for autonomous landing

The research of unmanned aerial vehicles＇（UAVs＇）autonomy navigation and landing guidance with computer vision has important signifcance.However,because of the image blurring,the position of the cooperative points cannot be obtained accurately,and the pose estimation algorithms based on the feature points have low precision.In this research,the pose estimation algorithm of UAV is proposed based on feature lines of the cooperative object for autonomous landing.This method uses the actual shape of the cooperative-target on ground and the principle of vanishing line.Roll angle is calculated from the vanishing line.Yaw angle is calculated from the location of the target in the image.Finally,the remaining extrinsic parameters are calculated by the coordinates transformation.Experimental results show that the pose estimation algorithm based on line feature has a higher precision and is more reliable than the pose estimation algorithm based on points feature.Moreover,the error of the algorithm we proposed is small enough when the UAV is near to the landing strip,and it can meet the basic requirements of UAV＇s autonomous landing.     

复杂电磁环境问题的产生与研究

简述电磁环境问题的产生历史及研究现状,并针对复杂电磁环境特性与模拟研究提出一些亟待解决的难点.通过分析典型战场电磁环境,对其构成、特性和作用有了初步认知;通过构建可控的电磁环境模型,为解决复杂电磁环境问题提供了一个虚拟研究平台.     

复杂电磁环境模拟的研究思路分析

通过分析装备复杂电磁环境适应性试验和复杂电磁环境下军事训练的需求,指出复杂电磁环境问题的根源在于对抗的不确定性.为了减少对抗的不确定性,提出复杂电磁环境模拟的总体研究思路,具体为作战对象的分析、敌方装备的技战术性能估计、威胁电磁环境预测,以及近似威胁电磁环境的生成实现和生成环境的监测与评价.     

Optimal robust non-fragile Kalman-type recursive filtering with finite-step autocorrelated noises and multiple packet dropouts

In this paper, the optimal robust non-fragile Kalman-type recursive filtering problem is studied for a class of uncertain systems with finite-step autocorrelated measurement noises and multiple packet dropouts. The system state, measurement output and filter parameters are all subject to stochastic uncertainties or multiplicative noises, where the measurement noises are finite-step autocorrelated. When there exist multiple packet dropouts in the system output, the original system is converted into an auxiliary stochastic uncertain system by the augmentation of system states and measurements. The process noises and measurement noises of the auxiliary system are shown to be finite-step autocorrelated and cross-correlated. Then, a robust non-fragile Kalman-type recursive filter is designed that is optimal in the minimum-variance sense. The proposed filter is not only robust against the uncertainties in the system model and measurement model, but also non-fragile against the implementation error with the filter parameters. Simulation results are employed to demonstrate the effectiveness of the proposed method.