超精密机床在线测量系统及其快速数据采集系统的硬件设计与研究

超精密机床是实现超精密加工的必要条件,它的研制成功对微电子、国防等尖端技术具有十分重要的意义。本文研究了超精密机床的关键部分——激光在线测量系统,并对其快速数据采集系统的硬件设计进行了深入的探讨,为超精密机床的研制奠定了基础。     

基于一维激光传感器的圆柱度偏差在机测量方法

针对回转体零件几何形状的在机测量与评价问题，结合反射式激光位移传感器研究了基于一维激光传感器的圆柱度偏差在机测量方法，并就圆柱度偏差在机测量模型和一维激光传感器测量与误差模型进行重点研究，提出了结合加工机床的基于一维激光位移测量的圆柱度偏差在机测量方案，通过实际测试验证了圆柱度偏差在机测量方法的合理性。该研究不仅具有较高的测量精度与工作效率，还可拓展机床加工与测量的能力。     

3维激光切割加工法矢测量系统

为了提高３维激光加工中示教录返编程的精度和效率,本文利用借机测量系统的概念,并采用激光点光源测头和３点测量法,研制了用于现有数控５轴联动激光切割机的法矢测量系统,通过精确测量加工轨迹上型值点的领域信息来实现加工所需信息－法矢的测量。     

基于无线传输的测振刀柄设计及实验研究

分析了铣削加工中振动信号在线检测技术的不足,提出将无线传感器系统集成在刀柄上实现加工振动检测的方案;提出了用于解决刀柄系统刚度、动平衡问题的刀柄结构设计方案;针对测振刀柄离线供电方式续航能力差的问题,通过综合运用多种休眠方式,实现了嵌入式测振刀柄系统采集传输程序的低功耗设计。设计铣削加工振动检测方式对比实验,验证了刀柄系统振动检测的性能。     

超精密机床激光干涉测量系统误差分析及补偿

详细分析了超精密机床加工中,激光测量系统误差组成及其产生机理,给出了有效的修正和补偿手段.影响激光测量系统精度和重复精度的主要误差因素可分为3类：内部误差、环境误差和安装误差.通过实例分析精密机床四轴激光测量系统,设计出了四轴激光测量光路,实现超精密工作台的X、Y、Rz三自由度位置反馈,给出了影响测量精度的误差因素以及对系统精度的影响大小.     

激光数字化仿形测量与加工系统

简要阐述激光数字化仿型测量与加工系统的基本原理以及在数控加工中心上的实现方法,探讨实现激光数字化仿型测量系统的软硬件条件、部分硬件电路以及集成方式。实践表明,激光数字化仿型测量与加工系统在机械制造领域有着良好的应用前景。     

双频激光定位测量系统波长变化规律的研究

双频激光定位测量系统是研制超精密机床的关键。双频激光测量是以波长为基准，本文分析了波长的变化规律。为提高在线测量的准确性与稳定性打下了基础。     

超精密机床定位测量技术

分析了国内外超精密机床及其测量系统的发展，并在我国首次提出将双路双频激光测量系统用于超精密机床的在线测量，经过稳频，信频和空气参数的补偿使测量系统达到０．０１μｍ的高分辩率。该系统数据采集快，结构紧凑，通过性好，为超精密机床的研制奠定了基础。     

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。     

三维焊缝形貌信息的变基准测量数据处理方法

为了实现大型航空航天薄壁结构件的精密激光焊接,在研制开发＂5＋2＂轴激光焊接测量系统的基础上,提出了一种变基准测量数据处理方法,通过齐次坐标变换,将表达在局部测量基准下的三维焊缝形貌信息转换到统一的机床基准下,建立了三维焊缝的几何模型,并对机床几何误差进行了分析与补偿。以某型号航空航天结构模拟件为例,通过在线测量、数据处理、几何建模以及编程加工进行验证,结果表明该方法能够满足实际加工的要求。     

在机测量激光测头位姿的线性标定

针对在机激光扫描测量中激光测头安装位置和姿态引起的测量误差,提出了一种适用于在机激光测量的测头标定方法。构造了在机激光扫描测量原型系统,建立了激光测头随机床运动的测量模型;通过多角度扫描标准球球面拟合球心,给出了一种线性求解测头安装位姿参数的算法,避免了非线性优化求解中的大量计算和不稳定问题。分析了测量过程中机床各个轴的运动误差对测量结果的影响,建立了误差模型,并给出补偿机床系统误差的方法。实验显示,对直径已知的标准球进行测量时,测头在不同摆角测得的标准球直径误差小于0.05 mm,误差补偿后球心位置误差减小了83%。实验结果验证了该标定方法的可行性,以及机床误差对测量精度影响的模型及补偿方法的正确性。     

基于激光三角法的圆度误差在线检测技术研究

提出了一种基于激光三角测距原理的圆度误差在线检测新方法。论述了检测系统的构成、测量原理和测量方法,讨论了主轴回转误差的分离,最后在普通车床上进行了实验验证,并用三坐标测量机作了对比测量,结果表明,两种测量方法的标准差均为0.75μm,两者间相对误差平均为4%。     

On-machine measurement using a noncontact sensor based on a CAD model

Once a machining process is finished, an inspection process is carried out to check whether the part is within dimensional tolerances. A coordinate measuring machine (CMM) is a general metrological device for assessment of dimensions on the shop floor. It cannot be ignored, however, that CMM measurements require significant resources in operating time and cost, which has led to many studies into on-machine measurement (OMM) systems. This study aims to develop an OMM system with a noncontacting laser displacement sensing apparatus and a computer-aided design (CAD) model for ease of operation, improved operating speed, and free form profiling. The system is composed of two software modules, one for sensor alignment with the machine tool and the other for measurement based on CAD/CAM (computer-aided machining). Consequently, the system was verified on the shop floor at a numerical control (NC) machining center.     

基于PowerINSPECT的在线测量技术研究

为提高零件的加工效率,实现数控加工后对产品质量的快速检验,提出了一种基于Power-INSPECT软件的在线检测方法。以典型的框类结构件为例,详细地阐述了检测数据点的生成、虚拟测量仿真和机床测量数据后处理等关键技术,并通过实际加工证明了该方法的有效性,提高了结构件数控编程的效率和质量。     

A differential laser autocollimation probe for on-machine measurement

An optical probe based on the principle of differential laser autocollimation has been developed for the purpose of on-machine measurement of mirror shapes. The probe is so compact that it can be mounted on diamond lathes. It can be rotated by a stepping motor about an axis perpendicular to the optical axis of measurement, and has been used to measure mirror shapes on an apparatus that imitates the conditions of an on-machine measurement system. The probe can reduce remarkably the measurement errors due to vibrational and thermal noises that could not be avoided previously in on-machine measurement. Estimating from repeatability, accuracy is better than 0.1 μm in measurement of a parabolic curve whose depth is >1 mm and length is ≈ 100 mm.     

基于三维激光扫描的移动大尺寸圆柱体工件长度快速检测系统

针对移动大尺寸圆柱体工件两端的表面形貌特征,利用三维激光扫描仪设计了一种快速长度在线检测系统。基于三维激光扫描仪可在短时间内连续高速获取大量测量数据的特点,系统在虚拟环境下构造出自适应测量形状的虚拟测量基准面,采用二维误差分离方法抑制系统误差和运动误差,识别定位工件两端端点并计算其到虚拟测量基准面的位移;最后结合多传感器融合模型获取三维位移场测量结果。另外,测试前用三坐标测量机精密测量过的相似形状圆柱体工件对系统进行了校准修正。为验证系统的精度和可靠性,分别对处于（1 000±25）mm内不同直径的圆柱体工件进行了长度检测。结果显示,系统可在1 s完成直径约为50 mm工件的长度测量,检测分辨力为0.010 mm,检测精度达到0.050 mm。实际运行结果表明,该设计系统具有高自动性和高效性,可满足在线生产中对大尺寸工件控制和检测的要求。     

An on-machine error calibration method for a laser micromachining tool

In this paper, an on-machine error calibration method, covering error modeling and measurement, is proposed to evaluate and compensate the errors caused by the mechanical and optical system equipped in the micromachining center using the femtosecond laser. Through preliminary tests by dicing silicon wafer, it has revealed that the squareness, laser beam misalign and focal position offset, are the main causes to result in the inaccuracy of micromachining. Consequently, an error modeling method is proposed to evaluate the error distribution in the workspace, and hereafter a comprehensive error vector of the laser beam, combining the squareness errors of Z-axis with the laser beam misalign, is generated by the variable substitution method. Subsequently, an increment error model in the instant local coordinates is established to satisfy the requirement of the programming method commonly used in the laser machine tools. Furthermore, a series of holes and grooves are machined on the femtosecond laser micromachining center to validate the proposed approach and model. The machining dimensions including diameters, distances and angles, are measured on-machine to identify the squareness errors, laser beam misalign and focal position offset according to the proposed error model. Finally, the experimental results show that, comparing to the uncompensated tests, the machining accuracy has been significantly improved with the proposed method.     

Mechanical model of errors of probes for numerical controlled machine tools

CNC machine tool probes are not only used to set up the workpiece before machining and to control it after machining, but also to determine volumetric errors of the machine tool. That’s why there is a necessity not only for knowledge of the complete on-machine measurement system errors, but also for the knowledge about probe’s errors in separation from machine tools. This paper presents a theoretical model of errors of probes for CNC machine tools. It takes into account such unique features of the machine tool probes as the transducer with support on the whole circumference and as wireless communication. 3 probes: RMP60, MP700 and IRP32.00-MINI were tested using moving master artifact method, out of machine tool, to verify the model described. The triggering radius values obtained experimentally were compared with values calculated using theoretical model, resulting with a compliance up to 92%.     

叶片进排气边光学测量系统的实现

针对航空发动机叶片进排气边的制造精度和一致性较差等问题,搭建了非接触式的叶片进排气边光学测量系统,以实现叶片进排气边的几何尺寸和轮廓形状的快速精确测量。该系统以传统的三坐标测量机框架为平台,采用由两个互成一定角度的新型激光扫描测头构成的专用测头作为前端传感器,并且内置了多种数据后置处理算法。在测量过程中,在每个叶片截面的进排气边处选取5条截线,分别测量这5条截线上的轮廓信息,从而确定叶片进排气边的几何尺寸和加工余量。该系统可以作为叶片加工系统的组成部分,从而将叶片的设计、制造和测量3个环节紧密地联系在一起。最后,应用该系统对某一精锻叶片的3个等高截面上的进排气边进行了多次测量实验,结果验证了所搭建的叶片进排气边光学测量系统的实用性和有效性,而且测量结果的重复性精度能够满足系统的设计要求和叶片进排气边的检测需求。该项研究为叶片进排气边的加工质量提供了一种高效率、高精度和高一致性的评定手段。