基于CCD成像的外圆纵向磨削表面粗糙度在线测量

为了提高外圆磨削加工零件表面粗糙度的测量效率,可以采用在线测量的方法.基于CCD成像技术,利用激光图谱比较法以及图像傅立叶变换后的能量谱,对外圆纵向磨削后的零件表面粗糙度进行非接触式在线测量,并判定加工零件表面粗糙度的等级.使用的测量方法,可以实现在线检测表面粗糙度的目的,达到了预想的效果.     

外圆纵向磨削表面粗糙度的在线检测研究

现代机械制造工艺对机械加工过程中的表面粗糙度的测量要求日益提高,不仅要保证测量精度,而且要提高测量效率。表面粗糙度测量有接触式和非接触式两种方法。接触式测量仪器稳定性好,示值客观、可靠,使用方便。但是,触针式表面粗糙度测量仪存在着易划伤软性材料表面、易使薄壁试件变形、测量速度低、测量范围小及不易实现自动化在线检测等弊端。而在表面粗糙度的非接触式测量中,光学法是测量的主体,其测量精度高,适合对软材料、易损工件以及某些带有有用信息的表面进行测量,可以较好地弥补触针式表面粗糙度测量仪的不足。目前光学法测量表面粗糙度的仪器有许多种,它们各有特点,但多数只限于在实验室良好环境下使用,能够在现场恶劣环境中对精加工后工件的表面粗糙度值进行在线测量的仪器并不是很多。     

小波分解自适应滤波算法在表面粗糙度测量中的应用

在对机械加工零件进行表面粗糙度的测量过程中,采集的表面原始轮廓信号伴随的随机噪声对表面粗糙度测量值的影响非常大。为了滤除噪声,将小波分解自适应滤波算法应用到表面粗糙度测量领域,设计出用于表面粗糙度测量的自适应滤波器,并采用小波分解与最小均方实现算法,算法简便,易于实现。仿真结果表明:小波分解自适应滤波方法在表面粗糙度测量过程中有较好的降噪效果,具有一定的应用价值。     

表面粗糙度光纤传感器检测装置的研究

一、引言在CIMS 中,表面粗糙度是监控加工过程和工件质量的最重要的参数之一。虽然目前的轮廓仪可以精确地检测表面粗糙度,但它不适用于自动制造中的在线测量和控制,而且对于超精加工而言,往往不允许进行具有破坏性的接触式测量。为此,人们一直试图开发非接触式的光电方法和装置来检测表面粗糙度。虽然强度型光纤传感器具有结构简单和价格低廉等优点,但光源光强的漂移以及某些干扰光对传感器的信号稳定性有极大的影响。如果能够有效消除这种影响,使测量信号足够稳定,则这种传感器应用的前景将是十分广阔的。采用强度型光纤传感器检测表面粗糙度是基于散射的原理,所以测量结果不仅与工件的加工质量有关,而且也与工件表面的清洁程度直接有关。因此,在采用光电法检测表面粗糙度时,工件表面的清洁处理必须规范化,这对于确保测量重复性至关重要。     

原子力显微镜在纳米粗糙度测量中的应用

介绍了用于纳米量级表面粗糙度测量的原子力显微系统。着重讨论了实现这种测量的软件实现方法。实验结果表明 ,该系统可以测量任意横向或纵向截面的线粗糙度 ,同时还可以测量任一区域的面粗糙度 ,并且在 X、Y、Z三个方向上的表面粗糙度测量精度均已达到纳米量级 ,完全满足纳米尺度形貌研究要求     

虚拟仪器技术在粗糙度测量中的应用

传统的轮廓仪与虚拟仪器技术相结合 ,构建新的粗糙度测量系统 ,实现表面粗糙度多参数测量与评定。     

表面缺陷的检测与评定

表面缺陷是评定机械加工工件表面质量的几何参量。我国和 ISO及各国标准都不把表面缺陷算作表面粗糙度范围 ,并要从测量中排除。但一般都指出 ,对表面缺陷如有要求 ,应另作规定。在执行 GB10 31— 83表面粗糙度国家标准时 ,正确理解表面缺陷的含义 ,合理区分与评定表面缺陷和表面粗糙度是一个很重要的问题。它不仅可以避免表面粗糙度的误测误判 ,而且有利于产品表面质量的提高。1　表面缺陷与表面粗糙度　　表面粗糙度是指加工表面上具有较小间距和微小峰谷所组成的微观几何形状误差。这种误差在加工表面上通常表现为刀具切削留下的刀痕 ;…     

基于激光散射光分布的表面粗糙度在线测量方法

介绍了基于光散射原理的激光测量装置非接触在线检测表面粗糙度。它利用半导体激光器为光源,CCD摄像头接收与表面粗糙度具有对应关系的散射光带,可同时得出表面粗糙度的值和试件表面纹理一致性的情况。并采取多种抗干扰措施,保证其可以对试件进行非接触在线检测。     

基于虚拟仪器的新型粗糙度测量系统的开发

利用轮廓仪与LabVIEW可视化的虚拟仪器系统开发平台相结合,本文开发了新的表面粗糙度测量系统。表面粗糙度评定参数的数学定义与功能模块程序相关分析,虚拟仪器的软件开发,实现了粗糙度多参数测量与评定。     

用激光散射法非接触在线检测表面粗糙度

介绍了基于光散射原理的激光测量装置非接触在线检测表面粗糙度的测量原理及测量头设计方案。调制光源、双光束、与测量光路同轴的高压喷气流、窄带滤波电路等设计可提高信噪比 ,增强抗干扰能力 ,可实现Ra2～ 1 0 0nm的表面粗糙度在线检测     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

Book Reviews

Book reviewed in this article: Advanced Scanning Electron Microscopy and X-ray Microanalysis . By Dale E. Newbury , David C. Joy , Patrick Echlin , Charles E. Fiori and Joseph I. Goldstein A Scanning Electron Microscope Atlas of the Honey Bee . By E. H. Erickson , S. D. Carlson and M. B. Garment Electron Microscopy of Proteins , Volume 5. Viral Structure . Edited by James R. Harris and Robert W. Horne Filtres Optiques . by M. Françon Optique Géometrique, Matricielle et Ondulatoire . By J. Ph . Pérez     

Research on the calibration method of precipitation micro- physical characteristics sensor

In order to diminish the effect of the ambient light and CCD pixel non-uniformity to the Precipitation Micro-physical Characteristics Sensor,a modified calibration scheme was designed and calibration experiments in sunny,cloudy,night,different location of sample space were carried out. Firstly,the characteristics of particle images which affected by ambient light and different location of sample space were analyzed. Secondly,the relevance betw een particle image features and parameters of image processing were discussed. Finally,the parameter setting scheme were determined,the radium of median filtering algorithm is 3 pixels,the defocusing radius of point spread function( PSF) is 7 pixels,the radium of erosion is 3 pixels,and the binary threshold is obtained from the Area-thresh relationship. The results show that the new scheme could deal with the image calibration well,the average errors of equivolumetric diameter was 0. 041 mm with standard deviation of 0. 115 mm,and the average errors of the axis ratio was 0. 011 with standard deviation of 0. 085. The new scheme works well in the field observation too,the observed axis ratio is consistent with the empirical relationship that proposed by Beard. The relative error of accumulation precipitation is-3. 06% after calibration,w hich is improved 1. 94% low er than the initial one without calibration.     

DSP工业测控系统关键技术研究

针对工业测控的现状和需求,提出新的测控方案,并对度数据采集及处理,提出并对双DSP的并行FFT的运算效率进行分析.基于RS485无线通信方式实现数据和控制信号的发送、接收.在上位机中用LabVIEw开发平台实现信号的接收与发送,并开发ODBC数据库接口,将虚拟仪器技术和面向Internet的Web技术有机结合起来,满足监测系统的互联和资源共享的需求.     

EXPERIMENTAL RESEARCH AND DESIGN ON HEAT TRANSFER OF EVAPORATOR USED IN THE LARGE QUICK FREEZE PLANT

The evaporator is the main part of a quick-freeze equipment. There are many factors influencing the heat transfer coefficient of an evaporator. The most important factors among them are the fin shape, tube diameter, distance of fin space, frost, and velocity of air flow etc. They mainly influence the thermal efficiency of an evaporator, and therefore its thermal efficiency has direct relationship with the whole efficiency of the quick freeze plant. Evaporators with different structural types have different heat transfer efficiency. In order to obtain high efficiency structure of evaporator, 8 evaporator models with different fin shape, tube diameter and tube arrangement are analyzed and compared. The calculation results show that the integral waved fins, equilateral-triangle arranged small diameter tubes and varying fin-spacing has the highest heat transfer coefficient. The experimental result also shows that the evaporator with this type of structure has better thermal efficiency. The experimental result is in good agreement with the calculation result. It can instruct engineering design for usual designer. A real quick-freeze equipment is designed and put into production. The result shows that, compared with traditional domestic quick-freeze equipments, this equipment decreases by 40% in size and by 20% in energy consumption.     

Surface metrology algorithm testing system

This paper presents the development of a Web-based surface metrology algorithm testing system. The system includes surface analysis tools and a surface texture specimen database for parameter evaluation and algorithm verification. The system runs from a Website at the National Institute of Standards and Technology (NIST), USA. Manufacturers, instrument makers, and researchers have access via the Internet to standard data sets and analysis tools located on a NIST server. The system serves to validate the accuracy of algorithms as well as the calculation of surface parameters in industry. The System can be accessed through http://syseng.nist.gov/VSC/jsp.     

Estimation of surface area and length with the orientator

The orientator is a new technique for the estimation of length and surface density and other stereological parameters using isotropic sections. It is an unbiased, design-based approach to the quantitative study of anisotropic structures such as muscle, myocardium, bone and cartilage. A simple method for the practical generation of such isotropic planes in biological specimens is described. No special technical equipment is necessary. Knowledge of an axis of anisotropy can be exploited to optimize the efficiency. To randomize directions in space, points are selected with uniform probability in a square using various combinations of simple random, stratified random, and systematic random sampling. The point patterns thus produced are mapped onto the surface of a hemisphere. The mapped points define directions of sectional planes in space. The mapping algorithm ensures that these planes arc isotropic, hence unbiased estimates of surface and length density can be obtained via the classical stereological formulae. Various implementations of the orientator are outlined: the prototype version, the orientator-gencrated ortrip, two systematic versions, and the smooth version. Orientator sections can be generated without difficulty in large specimens; we investigated human skeletal muscle, myocardium, placenta, and gut tissue. Slight practical modifications extend the applicability of the method to smaller organs like rat hearts. At the ultrastructural level, a correction procedure for the loss of anisotropic mitochondrial membranes due to oblique orientation relative to the electron beam is suggested. Other potential applications of the orientator in anisotropic structures include the estimation of individual particle surface area with isotropic nucleators, the determination of the connectivity of branching networks with isotropic disectors, and generation of isotropic sections for second-order stereology (three-dimensional pattern analysis).     

Research on key techniques of expendable conductivity temperature depth measuring system

This paper analysis the developing of expendable conductivity temperature depth measuring system(XCTD)and introduce its principle of measuring about temperature,salinity and depth of ocean.Some key techniques are put forward.According to the real needs of XCTD,conductivity sensor with high sensitivity is designed by principle of electromagnetic induce,the ocean conductivity from induced electromotive force has been calculated.Adding temperature correction circuit would help to reduce error of conductivity measurement because of sharply changing temperature.Advanced temperature measuring circuit of high precision and the constant current source is used to weaken effect of self-heating of resistance and fluctuation of the source.On respect of remote data transmission,LVDS is a good choice for the purpose of guarantee the quality of data transmitted and the transmission distance is reaching to thousand meters in the seawater.Modular programming method is also brought into this research aimed at improve the stability,reliability and maintainability of the whole measuring system.In February,2015,the trials in South China Sea demonstrate that the developed XCTD realize effective measurement at a speed of 6 knots and detection depth at 800 m.The consistency coefficient of the acquired data is greater than 0.99 and the success rate of probe launching is above 90%.     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

基于有限脉冲响应模型的飞机磁场补偿方法

通过分析飞机磁场数学模型,将飞机磁场表示成方向余弦与其乘积项的函数.鉴于模型参数之间存在很强的复共线性,提出了基于有限脉冲响应模型飞机磁场补偿方法.该方法将光泵磁强计和三轴磁强计的输出作为有限脉冲响应模型的输入,由带通滤波器提取信号中的变化成分,再用最小方差估计有限脉冲响应模型参数,并利用有限脉冲响应模型参数计算飞机磁场.从测量总磁场中减去飞机磁场,可得到目标信号磁场数据.最后,通过计算机仿真验证了该磁场补偿方法的有效性.