基于PSO-RBF的航空相机电源板故障诊断技术研究

针对机载航空相机电源板故障率高,传统故障诊断方法技术不足而造成的相机维护难度大的实际问题,提出一种基于PSO-RBF神经网络的电源板故障诊断方法。考虑选取RBF网络训练算法中隐含层节点数和中心参数的难题,采用实用粒子算法约简了RBF神经网络,设计了航空相机电源板故障诊断系统方案,并给出了诊断系统的软件模块和实现方法,实现了从计算机仿真到工程应用的电源电路故障诊断。仿真与实际检测实验结果均表明,系统在不依赖任何标准设备和附加测点时,可对航空相机电源板进行实时、全自动化故障检测,其故障现象的检测覆盖率为100%,故障诊断平均可靠性可达到97.73%,故障器件定位率可达到96.89%。     

某机载雷达发射校正系统的EMC设计

因受载机平台内电子设备电磁干扰的影响,某机载雷达发射校正时存在通道相位漂移的现象,表现为同一通道相位多次测量偏差超过正常幅度值.在阐述发射校正系统工作原理的基础上,深入分析干扰的来源和机理,提出了综合运用屏蔽、接地、滤波等措施解决电磁兼容问题的具体方法,实现了雷达发射校正系统的可靠工作,为该类工程设计提供了参考.     

影响摄像机标定的摄像机模型研究

文章讨论了摄像机模型中各种参数因子对标定结果的影响,评价了采用仿真数据模拟方式对参数的精度影响.     

多种测井曲线校正方法在塔中顺9井区的应用

针对顺9井区柯坪塔格组声波时差和密度曲线失真严重的问题。首先建立了工区的区域岩石物理模板判断测井曲线的失真段,然后使用了经验公式法、多元线性拟合法和岩石物理建模法对声波时差和密度曲线进行了校正。对比发现,经验公式法和多元线性拟合法适用于井眼垮塌较小的井段,而岩石物理建模更适用于井眼垮塌较严重的井段。最后利用区域岩石物理模板和合成地震记录标定约束并检验了曲线校正的结果。结果表明这三种曲线校正方法在顺9井区的应用是有效的、可行的。     

舰载光电经纬仪方位基准标校方法

光电经纬仪工作前,要对经纬仪的方位测量基准进行标校,安装在陆地的经纬仪通常以正北作为方位测量基准。而舰载光电经纬仪的方位测量基准是舰载的艏艉线方向。专业的测量舰船设有独立的用于光电经纬仪的标校系统,普通的测量舰船没有设置单独的标校系统,只设有指示舰船艏艉线的平面基准镜,平面基准镜的法线方向即是舰船艏艉线方向。为了将舰船艏艉线平面基准镜的法线方向通过光路折转的方法转到光电经纬仪的光学主系统视轴上,设计一种方位基准标校装置。该标校装置由两个自准经纬仪和两个折转光管及辅助固定支架组成。标校时可在测量舰船上临时安装,标校工作结束后即可拆除,安装、拆除工作简单易行。折转光管的结构简单,便于保管运输。     

材料烧结点测试系统及其图像处理

本文论述了材料烧结点测试系统的工作原理及其组成。采用数字图像处理技术 ,引入高速A/D转换及计算机系统 ,以实现对材料烧结点进行高效、可靠的测试。测试结果表明 ,这是一个实用的计算机自动检测系统。     

Detection of corrosion steel under an organic coating by infrared photography

The application of an infrared camera for detecting corrosion under organic coatings was studied. The ruptured blistering area, blister and filiform corrosion can be monitored easily by infrared thermography. When the corroded specimen is heated, the temperature at the surface over the corroded area changed differently according to the type of corrosion.The extent of increase in temperature was in the following sequence: ruptured blister > filiform filament > intact part > blister.From the analysis of temperature distribution at the surface of specimen, the location, shape and size of the corroded area can be estimated.     

New approach in tool wear measuring technique using CCD vision system

This paper suggests a reliable direct measuring procedure for measuring different tool wear parameters. Modern image processing techniques and machine vision systems today enable direct tool wear measurement to be accomplished in-cycle. The presented system is characterized by its measurement flexibility, high spatial resolution and good accuracy. The system consists of a light source to illuminate the tool, CCD camera, laser diod (used in conjunction with profile deepness assessment) with linear projector, grabber for capturing the picture, and a PC. The technique is specially characterized by its determination of profile deepness with the help of projected laser raster lines on a tool surface. So it has advantage comparing with other techniques, which can measure only 2D profiles. With the technique presented in this paper a 3D image of relief surface can be obtained without having need to employ a very complicated measuring system. All indirect methods like acoustic emission, force measurement, spindle current measurement, vibration sensors, etc. are very time consuming and demand very expensive subsidiary measurement equipment, compared with the method presented here.     

Simplified and efficient calibration of a mechanistic cutting force model for ball-end milling

Accurate evaluation of the empirical coefficients of a mechanistic cutting force model is critical to the reliability of the predicted cutting forces. This paper presents a simplified and efficient method to determine the cutting force coefficients of a ball-end milling model. The unique feature of this new method is that only a single half-slot cut is to be performed to calibrate the empirical force coefficients that are valid over a wide range of cutting conditions. The instantaneous cutting forces are used with the established helical cutting edge profile on the ball-end mill. The half-slot calibration cut enables successive determination of the lumped discrete values of the varying cutting mechanics parameters along the cutter axis whereas the size effect parameters are determined from the known variation of undeformed chip thickness with cutter rotation. The effectiveness of the present method in determining the cutting force coefficients has been demonstrated experimentally with a series of verification test cuts.     

Molten pool and temperature field in CO_2 laser welding

0IntroductionCompared with conventional welding methods,laserwelding has many advantages,such as large penetrationratio,small HAZ,small welding deformation.Another ad-vantage of laser welding is easy to weld complicated com-ponents because laser can be transferred by mirrors andoptical fiber.The laser welding will find wide applicationswith the laser system developing.Induced-plasma,molten pool and keyhole are mainphenomena in study of laser welding process.The varietiesof them indicate the …