三维扫描测头在齿轮测量中心的应用

为了解决三维测头在齿轮测量中心应用上的技术难点,通过构建三维扫描测头的多元非线性模型,规划出基准球的扫描路径,实现了对测头自身的垂直度、直线度、测针挠度以及与仪器坐标轴不重合等误差的校准。分析影响校准精度的因素,解决了三维扫描测头的标定问题,为后续工件的测量奠定了基础。由于三维扫描测头无法精确探测到给定的工件坐标点位置,测量时也无法严格按照预定的路径扫描,无法采取传统的电子展成法得到测量误差值。本文利用空间曲面理论实现了齿轮的测量及误差计算,通过对标准齿轮的检测,验证了方法的可行性,为复杂工件的一次装卡,全自动完成几何误差和形位误差的测量提供了条件,拓展了齿轮测量中心的检测能力。     

大尺寸长轴二维直线度测量方法研究

针对大尺寸长轴的特点,采用二维测头相互补偿的机理,提出了一种基于时域三点法的二维直线度测量方法。使用二维测头对长轴水平和竖直两维方向上的轴线进行直线度测量,既消除了导轨平移误差和竖直偏摆误差,又补偿了测头由于溜板水平偏转而脱离长轴母线时引起的误差。仿真和实验证实了二维直线度测量方法的有效性。     

纳米精度在位测量系统测头误差校正方法

针对超精密机床两轴联动接触式在位测量过程中测头误差影响测量精度的问题,提出了一种测头半径误差及形状误差校正方法。进行了在位测量实验,比较分析了测头误差未校正、测头半径误差校正及测头形状误差校正三种情况的测量结果,并分别与Taylor Hobson PGI840离线测量结果进行对比,以验证测头形状误差校正方法的有效性。测头形状误差校正后,面形精度PV值由420nm变为370nm,与离线测量PV值380nm的差值为10nm。结果表明,该在位测量系统测头误差校正方法有效,能够提高在位测量精度。     

封闭重构方法在RV摆线轮误差检测中的应用

摆线轮在齿轮测量中心上检测时采用一维测头采样机理,由于一维测头的敏感方向与齿廓法向误差定义方向不一致,导致误差计算过程繁琐,甚至误差结果不准确,不能真实地反映实际齿廓的加工形状.为此,提出了一种封闭重构方法,将其运用到RV摆线轮误差检测过程中,不仅能够精确获得摆线轮齿廓任一点的加工误差,而且误差结果能够反映齿廓的实际形状.基于封闭曲线重构理论,利用封闭曲线周期性延伸的特点,确定了首末端点节点矢量和首末控制顶点,实现重构齿廓在闭合点处完全封闭连续.在此基础上,建立误差计算模型,计算得到真实齿廓误差.通过实例对比验证了该方法的实用性和有效性,为后续精加工处理提供数据依据.     

时域三点法测量直线度信息高精度获取方法研究

常规时域三点法在直线度误差测量中会把零位和随机误差的影响迭代放大,使得直线度重构曲线失真,无法得到正确的直线度误差。通过对常规时域三点法数据处理误差放大机理进行研究,提出了基于比较消除法的误差等效均化的处理办法,并利用仿真和实验证实了其有效性和实用性。优化了时域三点法的直线度测量,使得直线度信息高精度获取成为可能。     

一种基于机器人的曲面测量、建模和加工方法

提出了一种基于机器人的卷曲类自由曲面的测最、建模和加T路径生成方法.本文采用结构光测量方法设计了一种基于机器人的自动测量系统,实现了自由曲面零件的表面测量.根据测量数据和零件的形状特点提出了一种新的建模方法,该方法首先采用提出的截面法直接提取点云的边界,然后利用射线与局部拟合曲面的交点获得有序的精整数据点,实现了NURBS曲面的精确拟合.最后,对重构的自由曲面采用等参数线法生成了加工路径.实际的算例和应用验证了本文方法的有效性和精确性.     

大尺寸直线度最佳测量间距计算方法

针对大尺寸直线度测量时,选取兼顾准确性和效率的测量间距困难的问题,通过基于奈奎斯特采样定理的大尺寸直线度测量间距理论计算方法提取了被测对象表面轮廓信号,并进行谐波分析,确定了影响测量间距的主要参数。针对工程应用中的理论计算方法需要事先对表面轮廓进行采样的局限性,在分析影响因素的基础上提出了基于直线度误差分布规律的测量间距仿真方法,用于指导实际测量时测量间距的选取。通过实验验证了仿真方法的正确性,并得出大尺寸直线度测量最佳测量间距为500mm,对于工程实际大尺寸直线度测量间距选取具有一定的指导意义。     

支持挤出平模头自动化研磨的测量技术

针对目前国内尚无快速、经济、有效的解决挤出平模头自动化研磨平模头直线度检测的现状,通过对测量对象的深入研究,建立了测量数学模型,提出了挤出平模头直线度测量方法。该方法通过计算机对一条假设的正弦波曲线进行测量精度模拟验证,并考虑定位误差等影响最终结果的误差;对得到的目标曲线按照形位公差国家标准,使用最小条件的原则进行直线度评定。通过几组实验的数据总结,从而验证此测量方法的可行性。     

三测头法误差分离技术的理论与试验

建立回转体零件频域三测头法误差分离数学模型,采用离散傅里叶变换法对误差分离基本方程进行求解,并通过计算机仿真对该数学模型进行验证和分析;采用经TALYROND262形状测量仪标定过的试件,在MB1332A半自动外圆磨床上进行圆度、圆柱度和轴线直线度误差在位测量对比试验,仿真结果和试验均成功地证明理论和数学模型的正确性,并得出结论:频域三测头误差分离方法基本上能实现各项误差的完全分离,适于在位测量,并可获得较高的在位测量精度。     

基于频域分析的长管型零件参数测量数据处理

为满足长管型零件的校直工艺要求 ,提出以工件旋转轴线作为基准测量工件直线度和内径的单测头或多测头测量方案以及基于频域分析的数据处理方法。该测量方法仅对工件旋转精度提出一定要求 ,可避免其它常用测量方法对长导轨的运动精度要求。     

Precision measurement of cylinder straightness using a scanning multi-probe system

This paper describes a scanning multi-probe system for measuring straightness profiles of cylinder workpieces. The system consists of two probe-units, each having three displacement probes. The two probe-units, which are placed on the two sides of the test cylinder, are moved by a scanning stage to scan the two opposed straightness profiles of the cylinder simultaneously. A differential output calculated from the probe outputs in each probe-unit cancels the influence of error motions of the scanning stage, and a double integration of the differential output gives the straightness profile. It is verified that the difference between the unknown zero-values of the probes in each probe-unit (zero-difference) will introduce a parabolic error term in the profile evaluation result, which is the largest error source for straightness measurement of long cylinders. To make zero-adjustment accurately, the cylinder is rotated 180° and scanned by the probe-units again after the first scanning. The zero-differences of the probe-units, as well as the straightness profiles of the cylinder, can be accurately evaluated from the output data of the two measurements. The effectiveness of this method is confirmed by theoretical analysis and experimental results. An improved method, which can measure the variation of the zero-difference during the scanning, is also presented.     

ALTERABLE INTERVAL OPTICALELECTRONIC AUTOCOLLIMATION METHOD FOR STRAIGHTNESS MEASUREMENT OF PRECISION GUIDE

0 INTRODUCTIONThe guide straightness strongly influences the performanceof kinetic parts, so straightness measurement[1-5] is widely ap-plied in engineering. An optical-electronic autocollimationmethod is widely used for high precision straightness measur…     

Identification and measurement of geometric errors for a five-axis machine tool with a tilting head using a double ball-bar

Geometric errors are one of the primary potential sources of error in a five-axis machine tool. There are two types of geometric errors: position-dependent geometric errors and position-independent geometric errors. A method is proposed to identify and measure the position-independent geometric errors of a five-axis machine tool with a tilting head by means of simultaneous multi-axis controlled movements using a double-ball bar (DBB). Techniques for identifying position-independent geometric errors have been proposed by other researchers. However, most of these are based on the assumption that position-dependent geometric errors (such as linear displacement, straightness, and angular errors) are eliminated by compensation, once the position-independent geometric errors have been identified. The approach suggested in this paper takes into account the effect of position-dependent geometric errors. The position-dependent geometric errors are first defined. Path generation for circle tests with two or three simultaneous control movements is then carried out to measure the position-independent geometric errors. Finally, simulations and experiments are conducted to confirm the validity of the proposed method. The simulation results show that the proposed method is sufficient to accurately identify position-independent geometric errors. The experimental results indicate that the technique can be used to identify the position-independent errors of a five-axis machine tool with a tilting head.     

基于蒙特卡罗法与GUM法的直线度测量不确定度评定

由于形位误差测量的复杂性和测量结果评定的多样性,导致在实际测量结果中形位误差的不确定度评定成了难题。通过GUM法和蒙特卡罗法对直线度的测量不确定度进行评定。首先,根据最小二乘法得到直线度的误差模型;然后采用GUM方法对测量结果进行不确定度评定,采用蒙特卡罗仿真方法对测量值进行模拟仿真,从而得到直线度误差的不确定度;设置实验对比,通过数据分析验证了蒙特卡罗方法评定的可行性,为形位误差测量结果不确定度评定提供了更加简便的方法。     

On-Machine Measurement of the Straightness and Tilt Errors of a Linear Slideway Using a New Four-Sensor Method

Although there are some multi-sensor methods for measuring the straightness and tilt errors of a linear slideway, they need to be further improved in some aspects, such as suppressing measurement noise and reducing precondition.In this paper, a new four-sensor method with an improved measurement system is proposed to on-machine separate the straightness and tilt errors of a linear slideway from the sensor outputs, considering the influences of the reference surface profile and the zero-adjustment values. The improved system is achieved by adjusting a single sensor to di erent positions. Based on the system, a system of linear equations is built by fusing the sensor outputs to cancel out the e ects of the straightness and tilt errors. Three constraints are then derived and supplemented into the linear system to make the coe cient matrix full rank. To restrain the sensitivity of the solution of the linear system to the measurement noise in the sensor outputs, the Tikhonov regularization method is utilized. After the surface profile is obtained from the solution, the straightness and tilt errors are identified from the sensor outputs. To analyze the e ects of the measurement noise and the positioning errors of the sensor and the linear slideway, a series of computer simulations are carried out. An experiment is conducted for validation, showing good consistency. The new four-sensor method with the improved measurement system provides a new way to measure the straightness and tilt errors of a linear slideway, which can guarantee favorable propagations of the residuals induced by the noise and the positioning errors.     

A high-precision five-degree-of-freedom measurement system based on laser collimator and interferometry techniques

A novel sensitivity improving method for simultaneously measuring five-degree-of-freedom errors of a moving linear stage is proposed based on collimator and interferometry techniques. The measuring principle and parameters of the system are analyzed theoretically. The experimental results proved that the resolution of the linear displacement of the proposed method has twice that of the current linear interferometer, and the resolutions of the two-dimensional straightness error measurement can be improved by a factor of 8 compared with the movement of the retroreflector itself by using multireflection and lens magnification. The resolutions of the pitch and yaw angular error measurement have been improved by a factor of 10 compared with the rotation of the plane mirror itself by using expander lenses. The whole measuring system is characterized of simple structure, small volume, and high precision. The moving component of the measurement system is wireless, which eliminates the errors and inconvenience introduced by the wire connection. Calibration and comparison tests of this system compared with Renishaw laser interferometer system have been carried out. Experimental results show good consistency for measuring a linear guide way.     

基于LabVIEW的数控机床形位误差精密测量系统

为了实现对数控机床形位误差精密测量,采用扭簧表及大理石平尺搭建导轨直线度测量装置,以HEIDENHAIN绝对式直线光栅尺为定位精度测量硬件,PC端通过数据采集卡获取测量信息,并基于LabVIEW开发虚拟仪器,实现了对数控机床导轨直线度、定位精度和重复定位精度项目的测量;提出了一种基于LabVIEW平台构建数控机床形位误差测量系统的新方案。在相同的检测参数下,对同一台数控机床进行检测,并与激光干涉仪测量的数据比对,激光干涉仪采用GB/T17421.2-2000统计分析方法,实验结果表明,本系统具备较高的测量分辨率和测量精度。     

并联轴直线运动直线度的检测与误差补偿

通过采用Renishaw激光干涉仪检测混联机床并联轴直线运动的直线度误差,对直线度的干涉测量原理和方法进行深入探讨,提出一种并联轴直线运动直线度的干涉测量方法和误差补偿模型的建模方法。分析干涉仪直线度评定方法和算法,做出并联轴直线运动直线度双向平均偏差特性曲线,建立直线度误差数学模型。利用最小二乘法拟合得到直线度均值误差补偿模型。对并联轴直线运动直线度进行补偿,达到了提高混联机床几何精度的目的。     

基于QMC的齿轮测量中心测量不确定度评定方法

为评定齿轮测量中心测量不确定度,提出了一种基于拟蒙特卡罗法(quasi Monte-Carlo method,QMC)的齿轮测量不确定度评定方法。研究了齿轮测量中心的几何误差源,应用坐标变换法建立了齿轮测量中心精密测量模型,采用拟蒙特卡罗仿真法对齿轮测量中心测量不确定度进行了评定,并分析了评定的稳定性。评定实验表明,该方法可准确评定齿轮测量中心测量不确定度,评定结果最大偏差为2.35%,评定方法稳定。