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。     

基于PSD的深孔轴线度测量机器人设计

针对目前深孔轴线度测试技术的不足,设计了一种基于PSD的自定心深孔轴线度测量机器人。通过螺旋管道机器人驱动,带动内径自定心装置沿管道轴线前进,置于定心轴端的激光头发出激光束并照射到外置的四象限PSD面板,通过电路转换和数据采集实时显示当前管道位置的轴线位置,并完成所测深孔轴线的测量。与现有测量系统相比,该机器人可以实现精密仪器中深孔、盲孔任意截面直线度参数的测量。     

珩磨测量头的动态误差分析

一、珩磨加工动态误差的分析与计算 在自控尺寸的珩磨加工中,珩磨头即是珩磨头,又是测量头(图1)。它是根据空气动力学喷嘴挡板结构原理进行测量的。其结构原理见本刊1981年第8期“珩磨气动自动测量系统”。 珩磨测量头在加工中的理想位置是其轴线与被测孔轴线相重合;两喷嘴中心线与这条公共轴线垂直,并且测量喷嘴两边的测量间隙相等(如图2中虚线位置)。但是,由于测量头制造误差和磨具磨损不一致,在测量中产生如下3种位置误差:位置偏移误差△x;不等间隙位置误差△y;位置倾斜误差△k。 1.位置偏移误差 珩磨测量头轴线与被测孔轴线平行,两喷嘴…     

一种大尺寸孔轴线非接触测量方法研究

为了快速,精确的获取大尺寸孔的轴线空间位置,实现轴孔组合零件的高精度装配,基于激光三角位移测量原理,提出了一种针对大尺寸孔轴线的非接触精密测量方法,据此设计出一种光学探头非接触测量系统,建立了对应的数学模型,数据处理上借助MATLAB最小二乘法实现对扫描轮廓曲线、孔中心轴线的拟合,最终得出被测孔轴线的空间位置方程,同时对测量系统进行了误差分析与补偿,该方法可以快速,高精度的获取大内径孔轴线空间位置,为后续轴-孔零件的高精度装配提供装配基准。     

激光跟踪测量系统角度自动校正装置设计

激光跟踪测量系统是目前最新型的便携式空间大尺寸坐标测量系统,利用激光干涉测长、精密测角及目标跟踪技术,可对任意点的空间位置进行实时跟踪测量。然而,目标反射器接收角度的大小严重影响了激光跟踪测量系统角度测量精度,为解决激光跟踪测量系统在动态测量中因角锥棱镜逆反射器接收角度范围限制而导致无法测量问题,研制开发了一种能使激光跟踪测量系统在动态条件下连续测量的角度自动校正装置。它主要由精密圆形导轨和角度方位自动调节机构组成,能使角锥棱镜在动态测量过程中始终指向激光跟踪测量系统,从而实现在动态条件下的连续工作。最后利用研制角度自动校正装置对激光跟踪测量系统进行了角度误差补偿实验,结果表明该装置使激光跟踪测量系统的水平角测量误差由34.69µm减小到9.71µm,垂直角测量误差由35.43µm减小到10.03µm,从而有效地提高了激光跟踪测量系统的角度测量精度。     

基于惯性基准的大尺寸空间角测量

针对大型装备装配过程中的大尺寸空间角测量问题,提出一种基于惯性基准的大尺寸空间角测量方法并且设计了相应的测量系统。该测量系统利用自准直原理获取被测轴线方向,通过内部陀螺仪和编码器测量被测轴线在惯性坐标系中的单位向量坐标,然后根据每个被测轴线在公共基准内的单位向量坐标值实现空间角的计算。建立了大尺寸空间角测量的数学模型,并对测量系统的测量不确定度进行分析和计算。最后搭建了测量系统的原理样机并利用原理样机在实验室进行了模拟测量实验。实验结果表明,原理样机的实际测量误差为14",满足了测量精度的要求。该方法采用惯性空间作为公共测量基准,有效地解决了测量大尺寸空间角时测量基准难以建立和传递的难题,使得测量过程更加灵活、高效。     

内孔键槽对称度测量装置

对于内孔键槽对称度的测量,基准轴线中心模拟较困难。目前,工厂还没有一种适合现场快速测量的装置。针对这种情况,笔者特设计了一种快速测量内孔键槽对称度的装置,具有结构简单,使用调整方便,测量效率高,测量精度好等优点。一、装置结构图1是该装置的结构,由孔基准轴线中心自动模拟器和孔键槽对称度测量器两大部分所组成。 1.孔基准轴线中心自动模拟器孔基准轴线中心自动模拟器是按普通游标卡尺测量工件内孔的原理设计的,因此,该部分不但能自动模拟被测工件孔的基准轴线中心,而且还能对孔进行直接测量(测量精度为0.02)。该部分由主尺、副尺(游标)、螺杆、可调旋钮等零件组成。主尺固装在测量基     

非接触激光测头测量轴线标定系统

提出一种用于三坐标测量机的非接触激光测头的标定系统，该系统利用位置敏感探测器和特别设计的测头夹具机构对非接触激光测头测量光束的轴线进行调整，使其通过测头回转体的回转中心。文中对具体的夹具结构标定方法以及数据分析方法做了详细的论述。     

激光三角法内孔测头固有几何参数标定方法

为了实现对内孔零件几何参数的完整测量,内孔测头除包括激光三角位移传感器外,还应包括带动传感器回转的机构和支撑壳体.受被测孔自身尺寸和传感器测量范围的限制,传感器回转轴线与其发射激光束可能因异面而存在偏心值a;此外,传感器输出的测量值是参照传感器内某一平面,但传感器回转轴线与该参考平面间也会存在偏移距离b.a和b是此类内孔测头的固有参数,与测量结果直接相关,但在整个测量过程中不变,需要对其进行参数标定后才能用于内孔几何参数的精密测量,最后提出一种标定此类内孔测头参数a和b的方法,并进行了实验验证.     

车载经纬仪的测量误差修正

载车平台变形会直接导致经纬仪方位旋转轴线产生倾斜,从而影响经纬仪的测角精度。为补偿测角精度,实现活动站测量,通过球面几何推导了平台变形对光电经纬仪测角误差影响的修正公式,利用光电轴角编码器精度高、采样频率高的特性,测量出经纬仪坐标系倾斜,经过坐标变换推导出经纬仪倾斜角和倾斜方向,该测量装置通过时统终端与经纬仪望远系统同时记录测角数据及倾斜数据,从而对测角误差进行修正。实验结果表明,该方法能够实时有效地补偿因平台变形而带来的测角误差,使经纬仪不落地测角精度控制在20″内,为实现高精度车载光电测量提供了一种有效的途径。     

A laser sensor with multiple detectors for freeform surface digitization

An integrated laser scanning sensor for freeform surface digitization is presented. The sensor consists of a diode laser light source and four position-sensitive device (PSD) detectors. The stand-off distance of the sensor is 180 mm and the measurable range is 90 mm. The Lambert model is applied to calculate the displacement between the sensor and the measured point on the object surface along the optical axis, under the assumption of a diffusive surface. The inclination angle of the measured point from the vertical plane of the laser beam is calculated by mathematical inference. Those data are used in error compensation to improve system precision. The new design of multiple detectors could increase the measurable angle and could solve the dead space problem in single point laser of triangulation measurement. The computer simulation and actual measurements show that the displacement resolution reaches 50 μm, and the system performs well in regards to stability and repeatability. The sensor system could be mounted on the NC machine orX-Y platform for freeform surface digitization.     

Development of an optical measuring system for integrated geometric errors of a three-axis miniaturized machine tool

Miniaturized machine tool (mMT) is one kind of downsized machine tool derived from conventional machines to manufacture miniature parts. However, it is extremely difficult to calibrate an mMT due to its small dimension. This paper presents a novel method that uses laser diode and optics to measure integrated geometric errors (three translation errors and three rotational errors). The squareness error between two axes is calculated by the least-square method. These seven errors are acquired simultaneously in one setup for each motion direction. The proposed measuring system consists of laser diodes, beam splitters, and 2D position sensing detectors (PSDs). The relationship between the PSD readings and the geometric errors calculated by the algorithm based on homogeneous transformation matrix is derived according to the configuration of measured mMT. Simulation is carried out to prove the validity of this algorithm. Sensitivity analysis based on the mounting errors of system components is also presented in this paper. Finally, an experiment is executed to verify the feasibility of the proposed measuring method.     

A laser sensor with multiple detectors for freeform surface digitization

In this paper, an integrated laser scanning sensor for freeform surface digitization is presented. The sensor consists of a diode laser light source and four position-sensitive device (PSD) detectors. The stand-off distance of the sensor is 180 mm and the measurable range is 90 mm. The Lambert model is applied to calculate the displacement between the sensor and the measured point on the object surface along the optical axis, under the assumption of a diffusive surface. The inclination angle of the measured point from the vertical plane of the laser beam is calculated by mathematical inference. Those data are used in error compensation to improve the system precision. The new design of multiple detectors could increase the measurable angle and could solve the dead-space problem in the single-point laser of triangulation measurement. The computer simulation and actual measurements show that the displacement resolution is around 50 μm, and the system performs well in terms of stability and repeatability. The sensor system could be mounted on the NC machine or on the X–Y platform for freeform surface digitization.     

非同轴激光雷达重叠因子的自校正系统设计

受振动，温度，预紧力变化等外部环境因素影响，激光雷达系统的激光发射光轴和望远镜接收光轴会发生变化，导致激光雷达系统的重叠因子发生变化，进而影响激光雷达系统的远场探测精度与探测稳定性。针对非同轴激光雷达提出开展重叠因子自校正的软硬件系统设计，采用二相电机驱动，具有自锁功能的蜗轮蜗杆发射光轴较正平台设计并搭建了激光发射光轴倾角调节系统，并以激光回波信号强度为校正判据寻找非同轴激光雷达系统收发光轴的最佳匹配位置。自校正过程采用粗扫描和细扫描相结合的方式，以实现校正精度和校正效率的综合考量，其中粗扫描采用环形扫时序，可在961 s内将激光发射光轴锁定在0.4 mrad×0.4 mrad倾角范围内；细扫描采用S形时序，可在441 s内实现激光发射光轴0.02 mrad的倾角调节精度。自校正前后的大气回波距离平方修正信号表明，设计的自校正系统能够实现非同轴激光雷达系统重叠因子的有效校正，并提升系统探测性能，为全天时，无人值守的激光雷达大气探测提供支持。     

A measuring method for large antenna assembly using laser and vision guiding technology

In this paper a new conception of a measuring method is proposed to assist precision automatic assembly of large radar antenna. Different from conventional 6-DOF tracking methods, the measuring system decomposes the measurement task into several independent steps. The measuring system consists of a camera, two laser distance meters, two position sensitive detectors (PSD) and an inclination angle sensor. The camera is adopted to guide antenna position and orientation adjustment over a large space. Laser meters and PSD sensor is used to precisely measure the position and orientation of radar antenna. To improve the practicability of measuring system, a robust vision measurement method is proposed. The mathematical models and practical calibration methods for measurement are elaborated. The preliminary experimental results agree with the methods currently being used for orientation and position measurement. The measuring method provides an alternative choice for the metrology in precision assembly. By using the method proposed in this paper, the measuring system can achieve a measurement accuracy of approximately 1 mm, which meets the accuracy requirement of large radar antenna automatic assembly application. Besides, the measuring method provides an alternative solution for large scale metrology which take the environmental impact into account.     

Comprehensive experimental study of liquid-slug length and Taylor-bubble velocity in slug flow

Slug flow is an intermittent two-phase flow pattern that provokes undesirable pressure variations in pipes. Mathematical models are commonly used to study these variations; so that it is necessary to know the experimental liquid-slug length, Taylor-bubble length, and pressure drop to validate such mathematical models.In this work, we experimentally studied the water-air slug flow through an acrylic pipe loop 6 m long and 0.01905 m internal diameter. We assembled infrared sensors on the acrylic pipe to get voltage signals accordingly to the presence of liquid-slugs or Taylor-bubbles. We applied Fourier transform on the voltage signals to obtain dominant frequencies to determining the liquid-slug length.Moreover, we obtained the cross-correlation function to get the delay time between two groups of the voltage signals to determine the velocity of Taylor-bubbles. Additionally, we measured the liquid-slug length by video technique and pressure drop with a digital manometer. The liquid-slug lengths obtained by using dominant frequencies are in agreement with the ones measured by video technique.On the other hand, Taylor-bubbles could touch or not the wall pipe at different inclination pipe angles; this affects pressure drop. Then, we observed the inclination angle when the Taylor-bubble detaches from the wall of the pipe, under different flow conditions. We found that the Taylor-bubble detaching angle is 45°, and as the inclination angle is higher, the slug-liquid and Taylor-bubble lengths are smaller. The detaching angle can be used as a criterion to neglect the gas shear-stress into mathematical models to improve predictions of the hydrodynamic behavior of slug flow.     

基于球形目标的激光位移传感器光束方向标定

搭建了非接触式的三坐标测量系统以便精密测量三维型面。将激光位移传感器通过具有两个回转轴的回转体安装在测量机的Z轴上,从而可根据待测表面的形状来调整传感器的方位。为了使传感器在各个方位上实现测量功能,提出了基于球形目标的光束方向标定方法,并详细阐述了其数学原理。标定时,驱动测量机使传感器分别沿测量机的X,Y和Z轴做等间距步进,根据步长和激光束长度的变化建立方程组求解出激光束所在直线的单位方向向量。最后,多次测量尺寸参数已知的六面体标准块规,检验了该测量系统的重复性。结果显示,该系统的测量不确定度为0.048mm;测量另一直径已知的被测球时,传感器在各个方位上的误差小于0.05mm,表明所提出的标定方法使测量系统达到了逆向工程的使用要求。得到的数据表明,本文所提出的方法有较高的标定精度和较好的重复性,为实现三维型面的快速扫描测量奠定了基础。     

Application of a diffraction grating and position sensitive detectors to the measurement of error motion and angular indexing of an indexing table

In this paper, two systems for the measurement of the error motion and angular indexing of a rotary indexing table have been developed. A laser diode, a laser holder and a position sensitive detector (PSD) are integrated as a simple measuring device for the measurement of the rotary error without using a precision reference artifact (a cylinder or a sphere), multiple probes or error separation methods. The laser diode is assembled in the laser holder and fixed on the rotary table. The PSD is set up above the laser holder to detect the position of an incident laser beam from the laser diode. When the rotary table rotates, the rotary error changes the direction of the incident beam and also the position of the spot on the PSD. For the measurement of the angular indexing, a reflective diffraction grating and two PSDs are integrated as a high-resolution angle measuring device without using an autocollimator or a laser interferometer system. The diffraction grating is set at the center of the rotary table and reflects an incident laser beam into several diffractive rays. Two PSDs were set up for detecting the positions of ±1st-order diffraction rays. A simple algebraic method is used to solve the angular indexing through an optical analysis. The experimental results showed the feasibility of the proposed test devices.     

激光位移传感器在自由曲面测量中的应用

以点激光位移传感器(HL-C211BE)为对象,研究它在自由曲面测量中的应用。针对激光位移传感器因测点倾角代入的测量误差,提出了一个可以量化的倾角误差模型。基于直射式点激光三角法原理,分析了激光光路的几何关系,从会聚光斑光能质心发生的偏移推导出倾角误差模型。随后,用高精度激光干涉仪和正弦规对激光位移传感器进行校对实验,并用误差模型对测量结果进行补偿。结果显示,补偿后激光位移传感器的测量精度得到明显提高。对一非球面凸透镜进行了实验测量,得到了自由曲面测点倾角的计算方法,并用倾角误差模型修正了测量数据。实验结果表明,量化的倾角误差模型可以将激光位移传感器的测量误差控制到小于10μm,满足激光位移传感器在自由曲面测量中应用的要求。