我国研制出新型测量装置

一种高精度的新型光学二维图形圆度测量装置在中国计量科学研究院研制成功并通过专家验收。该装置首次将圆度测量的标准方法与影像探测技术进行结合，实现二维圆图形高精度圆度校准，准确度达到世界先进水平，解决了高精度影像测头坐标测量机的溯源问题。     

逆向工程中基于线结构光视觉传感器的光学坐标测量系统研究

研究了将线结构光学视传感器作为三坐标测量机的光学测头,开发非接触式光学测量系统及其在逆向工程中应用的有关技术问题,主要内容包括线结构光视觉传感器与ＣＭＭ集成测量模型的建立与标定技术,测量视角的规划技术,多视角测量数据的配准与拼接技术等。实验结果与本文开发的光学坐标测量系统是有效的。     

亚微米级高精度复合式坐标测量机的研制

坐标测量机(CMM)是最常用的长度测量仪器,但在面对复杂结构工件的高精度测量时,配备单一接触式测头的坐标测量机往往无法完全满足测量需求。针对这种情况,本文研制了一种亚微米级的高精度复合式坐标测量机。该仪器集成接触式测头、影像测头和光谱共焦测头,充分利用每种测头各自的优势,实现复杂工件的快速高精度测量。本文介绍了高精度复合式坐标测量机测量精度影响因素的处理方法,完成了测量机的机械结构设计,进行了几何误差和热误差补偿,对测量机3种测头进行了独立标定及融合标定。精度验证测试结果表明,所研制的复合式坐标测量机测量精度可达到亚微米级水平。     

OMNI Sip三维万向测头

测头是坐标测量机的关键部件，直接关系到测量机的工作效率和测量精度。坐标测量机测头按测量方式可分为接触式和非接触式两大类。接触式测头又可分为机械式、电气式和光电式；非接触式测头则包括光学显微镜测头和电视扫描测头等。本文介绍的瑞士Sip公司生产的OMNISip三维万向测头属于接触式光电测头。一、工作原理OMNISip三维万向测头（见图1）可在空间以任一方向进行探测。测头的设计遵循了以下计量原则：①测头无内部摩擦；②对探测方向无限制；③无非线性轴向运动。测头本身就可看作是一台微型测量机。测头内有一个可向任意方向运…     

展品荟萃

西安爱德华测量设备有限公司,此次参展机器: MCMS系列,接触式三坐标测量机。利用坐标测量技术、计算机测控技术及最先进的动态测量系统进行工件表面点的采集和数据处理。可使用双旋转测头系统及不同测杆、测头的组合,配合各种通用或专用测量软件,方便实现对三维工件的测量。 U-SCOPE系列,非接触式两坐标测量机。使用先进的CCD摄影技术、计算机图像处理技术和影像灰度分辨技术,建立了二维非接触测量的全新概念,是万工显、投影仪、显微镜的升级换代产品。 UCMS系列,复合式三坐标测量机。将现代的光学测头、     

长跨度孔系直径与同轴度误差测量系统

针对飞机铰链件长跨度、小直径孔系的直径和同轴度误差高精度测量问题,研制了基于光电传感器的综合测量系统。多功能测头中的直流电机驱动自定心机构确定孔截面测量位置,光电编码器记录电机有效转动量,通过与标准环规进行比较间接测量各孔直径。以激光作为准直基准,安装在多功能测头前端的PSD检测激光光斑位置以确定各孔截面中心坐标,并进而评定出孔系的同轴度误差。使用该测量系统完成了孔系直径测量试验和PSD光斑检测线性及重复性试验。试验结果表明,与三坐标测量机测量结果相比,孔径测量相对误差小于10μm,PSD光斑位置检测重复性误差小于13μm,具备了较高的检测精度。     

高精度复合式测量中二维坐标统一方法研究

多测头坐标统一是复合式测量中的关键技术之一,根据多个测头对某一物件的测量值从而得到更加全面可信的信息.针对高精度复合式坐标测量中标准球作为多测头坐标统一标准器的不足,本文利用角度量块作为标准器实现了影像测头和接触式测头的高精度坐标统一.文中对比标准球和角度量块作为高精度复合测量中坐标统一标准器的优缺点,理论分析和实验结都证明通过使用角度量块作为标准器精度更高也更方便,且两测头在二维平面上能够实现高精度坐标统一.     

影像坐标测量机的性能评价

目前我国还没有非接触式影像探测坐标测量机的相应标准和校准规范。国际标准ISO／DS10360—7：2008对影像坐标测量机的性能评价，包括采用标准设备、各技术指标评价方法、符合性判断等做出了明确规定。本文简要介绍了该标准及附录的主要内容。     

三维螺纹测量机接触式测头的优化设计

为削弱接触式测头对高精度三维螺纹测量机精度的影响,设计了一种接触式测头结构尺寸优化方案,并提出了相应的标定方法。通过有限元仿真和正交试验优化测头结构参数,确定最优结构参数;利用坐标变换理论和最小二乘法原理建立测头标定模型并进行了标定试验;通过不同预压量下的螺纹塞规对比试验及螺纹环规、塞规对比试验对优化后的测头进行测试。结果表明：接触式测头测量螺纹塞规、环规参数标准偏差在1 μm左右,满足三维螺纹综合测量机接触式测头测量精度要求。该优化方案及标定方法为测头结构设计提供了重要的理论基础。     

关节臂式坐标测量机测量力误差分析及补偿

针对接触测量力对关节臂式坐标测量机(AACMM)测量精度的影响展开研究。对测量力引起的长度测量误差进行理论和实验分析,得到测头与被测件的局部变形、测杆的弯曲变形是影响关节臂式坐标测量机测头精度的主要因素。建立了关节臂式坐标测量机测头与被测件的局部变形、测杆的弯曲变形的数学模型,并对测量结果进行了测量力误差补偿。实验结果研究表明,测量力引起的误差对接触式关节臂式坐标测量机测量精度影响很大。通过本研究成果,可在很大程度上补偿测量力引起的误差:平均长度测量误差降低82%左右,最大误差降低约47μm,有效地提高了关节臂式坐标测量机的测量精度。     

Machine tool probes testing using a moving inner hemispherical master artefact

The growing popularity of usage of touch probes for CNC machine tools has created an increasing requirement to test their accuracy. Indirect methods used until now, based on the measurement of a material gauge with a machine tool equipped with a probe, made the separation of machine tool errors from probe errors impossible. In this article, a new method of testing the probe accuracy, which does not employ a machine tool, is presented. This method employs a moving master artefact in the form of an inner hemisphere. The standard uncertainty of the determination of triggering radius variation is 0.35 μm.     

使用二维视觉测头实现三维测量的方法研究

提出了探针扫描和深度聚焦的两种方法,实现了使用二维视觉测头对Z向的测量。两种方法均基于自动聚焦原理。对采集到的图像去噪和聚焦曲线平滑后,使用峰值附近点进行高斯函数拟合,寻找准焦点。根据得到的XYZ向的数据实现三维重构。与接触式测量相比,本文方法Z向测量的最大偏差不到6μm。     

Micro-scale hole profile measurement using rotating wire probe and acoustic emission contact detection

The development of a new probing method to inspect the inner diameter of micro-scale holes is presented in this paper. This was accomplished by contact detection using acoustic emission with a Ø170 μm rotating wire probe tip. Contact is detected when the rotating probe approaches and impacts the hole’s inner surface. The effective diameter of the rotating probe is calibrated by using a high precision grade 0 Mitutoyo gauge block. The wire rotating probe used was fabricated with micro stainless steel wire and micro tubes. The probe’s effective diameter was compensated for in the measurement of the hole. The probe was used to measure the diameter and the roundness of micro-scale holes. Probes used in previous publications have different geometry than the probe in this paper and are used almost exclusively for external dimensions. Micro-scale holes of less than 1.0 mm in diameter and 10 mm in depth are successfully measured and the 3D profile is created accordingly. Also, the out-of-roundness values of each level spacing, 50 μm apart in height, are calculated.     

数控车床在线检测测头标定方法

由于数控车床在线检测的测头中心安装时不可能与回转中心同高,以及测球接触工件后要再经过一段微小的距离才会发出信号等,使得测头在Y向和X向等方向产生误差。针对这些误差,本文推导出其Y向和X向方向误差补偿标定公式,并用TP6C-T型测头在数控车床CK6157上得到验证。     

在机测量线激光传感器安装位姿的全局标定

针对三轴数控机床激光测头安装位姿误差造成测量误差且不易调整和校准的问题,提出了一种在机测量线激光传感器安装位姿标定方法。建立了线激光在机测量系统的数学模型,通过机床运动带动线激光测头对标定基准点的空间位置进行测量,基于手眼标定原理给出了关于测头安装位姿参数的线性求解算法,完成了对测头安装误差的全局标定。考虑了机床定位误差对于标定结果精度的影响,采用蒙特卡洛模拟进行了误差分析。采用半径为35 mm的圆孔进行测量验证,实验结果表明,标定后圆孔测量误差为0.051 6 mm,测量精度提高了约96%,实验结果验证了该标定方法的有效性和可行性。     

纳米三坐标测量机接触式测头触发控制

为高灵敏度纳米三坐标测量机(nano-CMM)接触式测头提出了一种高精度高效率的触发控制策略。该策略使用了一种自行研制的4-DVD接触式测头,工件接触测头产生的微小变形会导致测头产生灵敏度极高的触发信号。系统使用超声波马达整合不同驱动模式,实现了高速逼近和低速触发的有效结合。触发过程使用了二次触发策略,即第一次触发获得接触位置的范围,第二次触发用极低的速度,详细记录触发点附近的触发信号,并通过线性拟合的方式求得信号曲线转折点,即为触发位置。该方法解决了驱动分辨率和行程大小的矛盾。实验结果显示:该方法可以有效地避免测头系统的塑性形变,触发位置的重复性可在10 nm以内。结果表明,本文提出的nano-CMM接触式测头触发控制策略在保证精度和稳定性的前提下,表现出了良好的控制效率。     

Development of a fast mechanical probe for coordinate measuring machines

To decrease inspection times of workpieces, not only do coordinate measuring machines (CMMs) need to operate faster, but also the mechanical probing process requires attention in this field. This paper shows that impact forces attributable to probing are much higher than generally accepted measurement forces, which can result in workpiece damage. Furthermore, it is shown that probe tip bouncing can slow down the probing process and requires mechanical damping to reduce it. Based upon these findings, a fast mechanical probe system has been developed, equipped with an optical measurement system able to measure six degrees of freedom at high speed. The probe system is suitable for high-speed, single-point measurements as well as scanning purposes. The measurement uncertainty of the prototype is approximately 1 μm for probing speeds up to 70 mm/s.     

Evaluation of a multi-sensor horizontal dual arm Coordinate Measuring Machine for automotive dimensional inspection

Multi-sensor coordinate measuring machines (CMM) have a potential performance advantage over existing CMM systems by offering the accuracy of a touch trigger probe with the speed of a laser scanner. Before these systems can be used, it is important that both random and systematic errors are evaluated within the context of its intended application. At present, the performance of a multi-sensor CMM, particularly of the laser scanner, has not been evaluated within an automotive environment. This study used a full-scale CNC machined physical representation of a sheet metal vehicle body to evaluate the measurement agreement and repeatability of critical surface points using a multi-sensor horizontal dual arm CMM. It was found that there were errors between CMM arms and with regard to part coordinate frame construction when using the different probing systems. However, the most significant effect upon measurement error was the spatial location of the surface feature. Therefore, for each feature on an automotive assembly, measurement agreement and repeatability has to be individually determined to access its acceptability for measurement with a laser scanner to improve CMM utilisation, or whether the accuracy of a touch trigger probe is required.     

A Hole-Plate Artifact Design for the Volumetric Error Calibration of CMM

To measure the volumetric error of coordinate measuring machines (CMMs), a hole-plate artifact method was studied. Example designs of the hole-plate are shown using titanium and ceramic materials. The deflection by its own weight of the designed hole-plate is analysed using the finite element method. The hole distances moved by the deflection are shown in different hole-plate set-up cases, for vertical and horizontal positions. The influence of inside hole roundness as a measuring standard is also studied. Eccentric errors for different hole roundness are simulated. The hole-plate set-up errors are also discussed. A method for obtaining the parametric errors of a CMM is shown using the hole-plate as a measuring artifact for CMM positioning error. In addition, a method for measuring 2D and 3D length errors using the hole-plate data is introduced.     

Profile evaluation of radial Fresnel lens directly machined on roller molds by rotating-tool diamond turning

In Roll-to-Roll manufacturing of high-quality optical Fresnel lens films, a high-precision roller mold with super-fine surface quality is essential to precisely transfer the functional microstructures from the periphery roller surface onto the flexible substrate. Unfortunately, direct diamond turning of deep circular grooves on the periphery surface of a roller mold was considered infeasible. Recently, the team has developed a novel 4-axis interactive tool-workpiece motion, Rotating-tool diamond turning (RDT), as a solution to overcome this challenge. Experiments were conducted to justify the capability of the proposed RDT process by directly machining a radial Fresnel lens on a brass roller mold, but without precise 3D profile evaluation of the lens on the roller surface. On-machine measurement of the machined lens structures using 3D touch probe is not applicable because the diameter of the probe is relatively large to penetrate into steep grooves of the Fresnel lens. On the other hand, off-machine measurement using stylus profilometer will introduce inevitable alignment errors during the measurement and lead to mismatched machining and measurement coordinates, making it difficult to evaluate the 3D lens profile generated by the RDT process eventually. In this study, a compensation and comparison algorithm is presented to precisely evaluate the form error between the machined and designed features in a three dimensional manner. Alignment errors generated when positioning the roller mold on the stylus profilometer are investigated and quantified through analyzing the characteristics of this unique micro structure with Fresnel lens wrapped on the roller periphery. As a conclusion, the machined lens structure is compensated and restored to compare with the designed profile, and the form error is obtained with the sources of errors analyzed. Such profile compensation and comparison method can be applied in other measurement and characterization studies on evaluation of complex optical structures patterned on roller molds for Roll-to-Roll manufacturing of advanced functional films.