一种准全向超声收发装置

根据超声探头的声场特性,设计制作了一种准全向超声收发装置.该装置主要通过对13个TC40-16TR超声探头组成的三维阵列的结构设计,再辅以多通道同步发射、多通道抢答接收电路,实现准全向测距,为实现对近地面的飞行目标的定位提供了方便可行的测距装置解决方案.实验结果表明,该装置能够实现对半径为15 m的半球空间的可靠全向测距,测距标准差在5 mm以内.     

基于组合热膜探头的气体流量积算仪

介绍了一种新型的基于组合热膜探头的气体流量积算仪.对该组合热膜探头的温度特性进行了实验研究,设计了具有温度补偿功能的测量电路,给出了用该探头进行气体流量测量的实验数据.结果表明:该组合热膜探头在微小流量测量中具有较高的灵敏度和重复性,测量精度优于1%,测量范围度达100:1.     

探头中心频率与摩擦副材质对超声膜厚测量范围的影响*

目前超声膜厚测量研究均是在固定探头中心频率(或单一摩擦副材质)下进行的,未考虑探头中心频率与摩擦副材质的变化对膜厚可测量范围的影响。为定量分析2种因素对膜厚测量范围的影响,设计一种压电陶瓷驱动的高精度微调式实验装置,基于弹簧模型利用不同中心频率探头对不同摩擦副材质间的水膜厚度进行测量。实验结果表明:膜厚的可测量值随探头中心频率的增大而减小,随摩擦副阻抗值的增大而减小;与理论值相比,利用超声探头测量水膜厚度的相对误差均低于10%,验证了实验装置及方法的可行性。提出一种根据摩擦副材质和期望测量膜厚范围来确定探头有效带宽的方法并进行试验验证,可为工程实际中不同膜厚测量时超声波探头的选型提供参考。     

红外地平仪视场保护系统

为使风云一号C和风云三号气象卫星红外地平仪不受太阳辐射视场的干扰,研制了一种视场保护系统,对该系统的优缺点、视场确定方案、峰值信号的标定算法进行了研究。分析了红外地平仪在轨运行受太阳辐射干扰影响的严重性,对视场保护系统进行了比较。设计了非扫描机械式视场保护系统——太阳探头,研究了有效的测量装置,测量确定了太阳探头的视场范围,推导了太阳探头信号测量的理论公式。根据太阳穿越大气辐射的理论,给出了标定太阳探头峰值信号的方案,并进行了外场试验。风云一号C气象卫星在轨运行验证表明:太阳探头有效地保护了红外地平仪。因此,太阳探头装置成功应用在卫星姿态测量装置中,研究的太阳探头将同样运用于即将发射的风云三号气象卫星红外地平仪视场保护中。     

提升超声波测量可靠性技术研究

研究了一种超声波探头固定装置,并深入研究了该固定装置对超声波流量检测精度的影响。实验结果表明,随着探头固定装置载荷的增加,超声波信号幅值和传播延时随之增大并趋于稳定,流量测量的精度随着载荷量的固定而固定。该装置解决了一般非接触式超声波流量测量信号不稳定的缺点。     

超声波测膜厚技术的精度标定研究

由于齿轮、轴承等机械零件在使用中依靠润滑剂来降低摩擦磨损,而润滑剂的厚度会影响润滑的效果,因此对润滑剂厚度进行检测有重要的意义。超声波测量法是润滑剂厚度测量的一种无损检测法,但目前缺乏超声波探头的测量精度对实验结果的影响研究,因此设计了一种超声波探头测量精度的标定装置。利用此标定装置测量了3种材料(不锈钢、铝和PMMA)与水分界面处的反射系数,并基于共振法测量了不同厚度的水膜。结果表明超声波探头的测量误差低于5%,满足液体膜厚度的测量要求。     

电磁涡流无损探伤中探头位置检测装置

设计了一种电磁涡流无损探伤中探头位置检测装置,利用探头本身的电磁性质,在探头周围放置探头位置检测装置,再通过单片机进行计算,从而进行准确的定位。探头位置检测装置采用了4个位置传感器(4个线圈),用C8051F005单片机的DAC产生正弦波输出到探头线圈中,探头在空间内就会产生磁场,激励4个位置传感器产生感应电动势,再通过自动增益控制(AGC)电路放大和精密整流电路整流后,由C8051F005单片机ADC采样运算处理,算出探头的坐标位置。     

时域电磁法套管探伤技术三维有限元数值模拟

提出了一种非接触式套管探伤装置设计方案.采用有限元仿真技术,对装置中纵向磁探头与横向磁探头的时域电磁响应进行了数值模拟.结果表明,纵向磁探头产生与套管同轴的环状涡流,而横向磁探头产生的涡流方向与前者互相垂直.磁探头上的接收信号主要来自金属套管.分析了套管上存在孔洞、纵向裂缝和横向裂缝时,两种磁探头的响应特性.不同孔洞损伤的电磁响应计算结果显示,两种磁探头对孔洞直径的变化均具有较高分辨率.通过对不同参数纵向裂缝与横向裂缝电磁响应特征的讨论,认为横向磁探头对套管上纵向裂缝长度的变化无判断能力,而纵向磁探头对横向裂缝长度变化的识别效果较弱.不同套管损伤的实验结果证实了数值模拟的正确性.     

空间材料科学实验自动解锁装置的设计

设计了一种适用于空间材料科学实验旋转运动的自动解锁装置,完成了其关键零部件的设计和校核,并对解锁装置进行了解锁实验。实验结果表明:该自动解锁装置只需提供2.1N·m的解锁力矩即可解锁。     

核电站管道弯头超声检测装置设计及验证

本文设计了一种针对核电站管道弯头背脊拉伸区在役裂纹上的检测装置,确定其机械机构,包括机构原理、传动方式、运动形式。并对其中的主要结构扫查组件和探头组件的设计过程进行阐述,确定了检测方法、探头布置方式和扫查路径。还设计并组装了一套样机,模拟现场检测环境,验证装置的可行性,测试管道弯头在役裂纹检测装置的缺陷检出能力及扫查有效覆盖范围。     

线结构激光仿型测量中的视觉跟踪算法

分析国内现有线结构激光测量系统的特点,提出一各地ＣＮＣ系统的线结构激光仿型测量的视觉跟踪算法;该算法给出了一套较为完整的跟踪策略,解决了超视距和成像则头的自适应调节问题。     

激光三角法扫描测头特性的研究

在分析了激光三角法位移测量原理的基础上,以ＩＢ－１２型激光三角法位移传感器为实例,研究了激光三角法位移传感器的使用特性,补偿非线性误差、倾斜角误差,提高了测量精度,使其能够作为非接触式扫描测头用在三坐标测量机上,完成空间自由曲面的非接触扫描测量。     

扫描测头中CCD摄像机测量模型和坐标转换

基于激光三角法测量原理的扫描测头广泛应用于现代的工业生产中,现已成为人们研究的重点,而CCD摄像机是扫描测头的核心部位。本文通过介绍基于线结构光扫描测头的测量原理,引出了CCD摄像机的测量模型和坐标转换,使其成为研究扫描测头的核心技术。阐述了扫描测头在自主研制的关节臂测量机上的应用。     

自由曲面的二维自适应测量及测球半径的三维补偿

基于贝塞尔方法提出了针对自由曲面的自适应测量算法,并与传统测量方法进行了对比。在对自适应测量数据的处理中,提出了一种新的基于离散点三角剖分的测球半径三维补偿算法。通过仿真和试验验证,上述算法已成功应用于集成化柔性激光加工系统中。     

Ball array calibration on a coordinate measuring machine using a gage block

The distances between the balls of a ball array used in machine geometry calibration have to be very accurate. These distances can be calibrated using a laser measurement system, which requires specially designed optical devices and measuring probes. In this paper, a new and economical alternative method for calibrating the ball array is described. A single gage block is used for measuring the standard distance at the starting position. Then, the exact distances between the balls can be obtained by using the coordinate measuring machine (CMM) probe motion. This method does not depend on the accuracy of the CMM. Also, this method does not require expensive instruments or devices, but a CMM and a gage block. A simple “parallel-plane” bracket, mounted on to the measuring end of a CMM probe, is used to determine the centers of the balls automatically and accurately.     

基于隐藏特征测量的激光跟踪仪探头及其测量误差分析

介绍了一种测量隐藏特征和表面特征的激光跟踪仪探头(FaroRetroProbe)的结构和工作原理,详细分析了该探头的空心角锥棱镜误差、空心角锥棱镜和探针的对称性误差及平面反射镜的面形误差等主要误差及其对激光跟踪仪测量结果的影响,并针对性地指出提高激光跟踪仪测量精度的措施。     

Strategies and Processes to Measure the Dimensional Geometry of Sheet Metal Parts for Exact Laser Cutting

This paper describes strategies and processes to measure the dimensional geometry and deformations of sheet metal parts, in order to improve accuracy in laser cutting. A robust circular triangulation laser probe was integrated into a CNC machining centre. For the development of the measuring system a non-contact laser sensor and a personal computer (PC) were integrated information-technically with the NC-controller of the machining centre, as introduced in this study. To meet the demands of the measuring tasks in laser machining, the meas-uring uncertainty of the selected laser probe with respect to different measuring procedures, such as the fixed height procedure, surface tracing procedure, and profile-orientated procedure for steel and plastic materials, was investigated in this study. When measuring uncertainty is considered, the profile-orientated procedure best meets the accuracy requirements. According to the experimental results, the uncertainty could be minimised to within ±20 μm in the middle measuring range. To shorten the measuring time, a twofold measuring strategy was developed. The first step checks for existing deviations quickly. If necessary, in the case of deviations of the actual machining path from the theoretical machining path, these can be quantified in the second step. A nine-point measuring strategy was proposed in this study in order to calculate the surface normal of the deformed sheet metal. An algorithm for calculating the path correction using these deviations and the calculated surface normal with respect to the coordinates and the surface normal of theoretical path position, was also presented. The algorithms were verified using the developed automatic measuring system on a 4-axis machining centre with satisfactory results. One specific characteristic of the strategy presented is that the machining path can be verified for the case of laser cutting for workpieces without edges or marks.     

Integration of a laser interferometer and a CMM into a measurement system for measuring internal dimensions

In order to improve the existing comparative procedure for calibrating internal dimensions, we have developed a new measurement set-up for traceable absolute measurements. It consists of a co-ordinate measuring machine (CMM) and a laser interferometer (LI). The LI serves as a traceable measurement system, while the CMM is only used as a guiding system for the measuring probe. Extended research focused on defining probe parameters such as diameter, bending and indentation, as well as probing head repeatability and other error sources. The final goal of the research was to determine uncertainty of measurement under existing laboratory conditions. The main outcomes of the research and final uncertainty of measurement are presented in this article.     

非接触式五坐标测量机系统几何参数的辨识方法

针对所研发的非接触式五坐标测量机,介绍了其系统组成及工作原理。采用多体运动学理论与齐次坐标变换的方法建立了系统的测量数学模型。对于数学模型中的未知几何参数,提出了基于测量实物基准的参数辨识方法,实现了对三个未知几何参数的辨识。实验结果表明该方法是有效、可行的,三个几何参数辨识的重复误差都在2μm以内。     

On-machine profile measurement of a micro cutting edge by using a contact-type compact probe unit

A new contact-type on-machine measurement system is designed and developed for the evaluation of a micro cutting edge profile. The measurement system is composed of a compact probe unit having a sharp stylus mounted on a flexible beam, an inner displacement sensor for the detection of the stylus displacement, and a two-axis precision positioning system. For the evaluation of tool faces having a steep slope, a new probing procedure with the enhancement of the inner displacement sensor integrated into the probe unit is newly proposed. After the design and development of the probe unit, the feasibilities of the developed measurement system and the proposed probing procedure are demonstrated through some basic experiments. Regarding the out-of-straightness and angular error motion of the two-axis positioning system employed in the developed measurement system, a pair of length gauges is newly employed to reduce the influences of error motions of the stage system. The topographic profile of the micro cutting edge obtained by the measurement system with the modified probe unit is then compared with those obtained by a commercial stylus profiler and a laser confocal microscope. The feasibility and effectiveness of the developed on-machine tool edge profile measurement system are also demonstrated through uncertainty analysis based on the GUM with the Monte-Carlo method.