基于浮力的三维实体轮廓无损测量实验系统研究

设计了一种基于液体浮力的三维轮廓测量的实验系统和测量方法,阐述了该方法的测量原理.由阿基米德定律和杠杆原理,利用电子天平逐层测算被测实体浸入液面不同深度时所受浮力,通过计算机计算相应每片层的质量、重心等信息,推算出各层面上微小实体单元在三维坐标系中的位置,进而重构出被测实体的三维轮廓图像.经过初步实验,证明了该方法是切实可行的.     

基于均质实体的切片轮廓非接触三维测量方法

本文设计了一种基于均质实体的片层轮廓测量方法,阐述了该方法的测量原理,由阿基米德定律和杠杆原理,利用电子天平逐层测算被测实体浸入液面不同深度时所受浮力,通过计算机计算相应每片层的重力矩、重心等信息,推算出各层面上微小实体单元在三维坐标系中的位置,进而重构出被测实体的片层轮廓.经过实验验证,其结果证明了该方法是切实可行的.     

通用型二维轮廓形状评定软件的研究

为了完成各类零件的形状检测与评定,提高零件加工质量,针对零件二维轮廓的测量要求,设计了一套功能完备的通用型轮廓测量软件。在软件的编制过程中,以提高其通用性为原则,直接读取文本数据,并可评定二维形貌的各项设计尺寸;改进了直线度、圆度误差的计算方法,减少了计算机运算时间,提高了测量精度;设计了一项图形对比功能,可将设计尺寸与被测轮廓进行整体对比,以判定被测零件是否合格;提出一种交互式的所见即所得的打印方法,用户可自行设计打印版面,提高了打印文档的灵活性。     

二维轮廓测量仪的系统建模及标定

在分析轮廓测量仪测量原理的基础上,建立了二维轮廓测量系统的数学模型,构造了轮廓测量仪的硬件结构。研究了差动式电感传感器的输出特性,在此基础上提出了采用标准组合量块的传感器标定方法。分析了触针测头形状对被测轮廓数据的影响,并提出了对测头半径的两种数据修正方法。经实例验证,所采用的系统数学模型和传感器标定方法满足测量系统的要求。     

离散点的线轮廓度评价算法

为了实现微型零件轮廓的高精度测量,根据其成像特点,提出了一种基于离散点的轮廓度评价算法--被测轮廓与理论轮廓离散点间最小距离法.首先,提取出被测轮廓的边缘点信息,然后,依据理论轮廓计算出一系列间距极小的坐标点并建立坐标系.将被测轮廓点与理论轮廓点对应,最后将计算得出的每个被测轮廓点到最近理论轮廓点的距离作为该点的轮廓度误差.实验结果证明,测量精度优于2 pixel,此方法町有效地提高线轮廓度的评价精度和效率.     

工件轮廓线参数校正方法研究

接触式轮廓仪是测量机械零件表面轮廓特征信息的有效工具,它可以对机械工件的轮廓、二维尺寸、二维位移进行测验与检验。在进行测量时,由于要与被测工件表面接触,就会存在由于探针沾污,探针缺陷以及扫描位置不准的现象,检测到的轮廓曲线会呈现出粗糙不平的情况,这给准确标注工件轮廓线带来了影响。本文以某工件轮廓线参数为基础,研究了一种工件轮廓参数校正方法。该方法可以根据工件在不同角度的轮廓线数据,计算出倾斜角度,同时设计了坐标变换模型,对其进行角度校正,给出了水平状态与倾斜状态下的模型误差。     

一种复杂二次曲面轮廓度评定方法

为了建立复杂二次曲面轮廓度评定中计算机数据处理的理论模型和实现方法,提出了一种不要求满足小误差假设、不使用微分线形化评定二次曲面轮廓度的方法。该方法首先通过最小二乘法得到一个初始二次曲面,然后用模式搜索对初始二次曲面系数进行调整,直到找到满足最小区域原则的理想二次曲面,其目标函数值作为被测曲面的轮廓度。在计算过程中使用坐标变换将一般型的二次曲面化为标准型,既简化了轮廓度的计算,而且被测曲面可以在测量范围内任意放置。对抛物面轮廓度评定表明目标函数随着模式搜索的进行逐渐减小,模式搜索得到的抛物面轮廓度值比用最小二乘法得到的轮廓度值小得多,因此该方法更好地反映了被测二次曲面表面形状误差。     

传动元件的有控点共轭啮合运动几何测量法

一、概述就传动元件几何形状精度的评定观点及相应的测量方法和原理而言 ,其测量法大体可分为三类。1 .几何坐标测量法这种测量法的基点在于被测件是一个几何实体。建立一个基准测量坐标系 ,将被测工件 (它有自身的坐标系 )放置在该测量坐标系中去进行度量。按照工件坐标系和测量坐标系的关系 ,测量出该工件上被检测轮廓形状 (点、线、面 )和理论虚拟几何体上相应处轮廓形状 (点、线、面 )的差异 ,它可归结为测量对应点坐标位置的差异 ,即测量头与被测传动元件之间为点接触 ,所测量的误差数值 ,为被测工件表面实际轮廓上对应该检测点的轮廓…     

零件轮廓测量软件关键算法的研究

为了完成各类零件的形状检测，提高零件加工质量，在分析触针式二维轮廓测量仪基本工作原理的基础上，针对零件二维轮廓的测量要求，设计了一套功能完备的轮廓测量软件。在软件的编制过程中，引进了形态学滤波算法，有效地滤除噪声、振动等干扰信号，并保留了有用信息，同时补偿了由触针半径引入的测量误差；改进了直线度、圆度误差的计算方法，减少了计算机运算时间，提高了测量精度；提出一种新式的螺纹标注算法，可以一次性标注被测螺纹，减少了工作量,提高了稳定性。     

基于图像的线轮廓度评价算法研究

根据微型零件的成像特点,为了实现其轮廓的高精度测量,提出了一种基于离散点的轮廓度评价算法——被测轮廓与理论轮廓离散点间的最小距离法：首先提取出被测轮廓的边缘点信息,其次依据理论轮廓计算出一系列间距极小的坐标点并建立坐标系将被测轮廓点与理论轮廓点对应,最后计算出每个被测轮廓点到最近理论轮廓点的距离作为该点的轮廓度误差。实验结果证明,精度优于1.5个像素,此方法可有效的提高了线轮廓度的评价精度和效率。     

基于体素数据造型与SolidWorks的三维重构算法的研究

根据浮力法测量到的正方体体素数据，经过数据排序等处理，排除冗余数据点，将整体数据分割成薄层数据，由VB软件调用SolidWorks2004构造实体模型，提取薄层截面轮廓线，在SolidWorks2004中实现实体表面顺滑，并最终重构出三维实体模型。     

新型浮力测量系统的设计

设计了一种新型的浮力测量系统,通过参数采集与处理,得出浮力与电流的关系,从而能实现对浮力自动测量,它能给测量带来很大的方便,具有测量误差小、速度快、精度高等特点,能有效地提高测量的精度和效益.     

Five-axis automated measurement by coordinate measuring machine

This research paper presents an analysis of the undercut interference and inclination interference caused by complicated 3D workpiece during measurement. The objective of this research is to propose a solution to the collision between measuring probe and workpiece for the purpose of automation and interference-free measurement. The fundamental procedure is based on the 3D CAD model of workpiece and five-axis coordinate measuring machine (CMM) measuring facility to generate an interference-free stylus orientation through three phases—adjustment of inclination angle under linear contour, adjustment of inclination angle under non-linear contour, and definition of rotation-free angle. Such manner not only solves the interference problems but also incorporates the minimization of counts of measuring probe rotation. In terms of methodology, the research adopts projection of cutting plane to determine the interference status of the measuring point, and based on the measuring inclination angle on the proposition of self-intersected contour and cross-intersected contour concepts, the range of safe rotation range can be determined by sweeping operation. Following the presented methods and procedures, the five-axis CMM simulation system for automated measurement is finally developed to validate the feasibility of proposed solution.     

平面和空间螺线的恒速插补算法

基于参数曲线恒速插补机理分析,建立了平面和空间螺线的恒速插补算法,讨论了插补误差及其有效近似计算,通过AutoLISP编程进行实例插补模拟。结果表明该插补算法无累计误差,具有恒速进给、插补精度易于控制等特点,便于现代通用PC微机数控系统进行开发和应用。     

A Study on an Evaluation Method for Form Deviations of 2D Contours from Coordinate Measurement

A practical approach towards evaluating form deviations of 2D complex contour profiles from the coordinate measurement data of discrete points is proposed. In this approach, a 2D complex contour is represented approximately by the combination of straight line and circular arc segments under the condition of satisfying the prespecified interpolation accuracy. The form deviation of a measured point is calculated relative to the approximate contour and the form deviation of the whole contour is evaluated using either the minimum zone criterion (MZC) or the least squares criterion (LSC). It has been demonstrated that the difference between the deviation definitions, one relative to the original contour and the other to the approximate contour, is not larger than the prespecified accuracy value, i.e. the evaluation precision of the form deviation can be sufficiently guaranteed. The effectiveness and the efficiency of the approach are verified with a practical example of a planar cam contour. Moreover, a weighted LSC technique is proposed in order to obtain a rational evaluation result for the measured points with non-uniform length interval.     

基于UG的双联齿轮参数化设计

双联齿轮的齿形轮廓形状复杂,参数驱动化设计困难,文中运用参数化三维软件UG．对圆柱直齿轮进行三维建模。通过模型模块中的规律曲线,建立齿形轮廓,通过与齿根圆柱布尔运算、拉伸、引入特征阵列等命令,建立双联齿轮三维模型,达到了改变基本参数,立即得到相应的双联齿轮三维模型的参数化驱动化设计。     

微压力接触式台阶仪的结构设计与实验研究

介绍了一种基于光电检测原理的高精度接触式二维轮廓检测仪。该仪器将CCD成像检测技术与接触式检测技术有机的结合起来,通过狭缝成像方式代替进口容栅和磁栅,实现对工件的高精度尺寸检测,具有接触压力小,成本低等优点。实验测得,仪器最小分辨率为1μm,多次测量重复精度为±5μm。     

Dual-field measurement system for real-time material flow on conveyor belt

In this paper, an innovative dual-field measurement system is proposed for measuring the real-time material flow on the conveyor belt. The system consists of two light sources to illuminate the upper and the lower surface of the conveyor belt, respectively, and two binocular cameras to capture the dual-field contour images. The contour curves are extracted from the images by the contour acquisition algorithm and fitted with linear interpolation functions for the calculation of instantaneous cross-sectional area of material flow. Then the real-time volume of material flow is obtained according to the belt speed. Compared with conventional visual methods, the proposed method is no need to preliminarily acquire the data of the empty belt as well as hardly affected by belt deformation. Some measured objects are prepared for both sectional area and volume measurement. The results show that the accuracy of the proposed system can achieve up to 96.3% and 96.05% for the volume measurement of regular materials and coals, respectively, which is superior to the conventional visual method. The proposed measurement method has strong robustness and low construction cost, which is expected to generalize and apply in the bulk material transport field.     

流干扰下的水下机械手动力学建模分析

研究了四功能深海电驱动机械手所受的水动力。以Morison公式为计算基础,利用拉格朗日方法,建立了流干扰下的水下机械手动力学模型。仿真研究了水阻力、浮力、定常流以及非定常流对水下机械手动力学的影响。结果表明,在各水动力影响因素中,浮力影响最大,流干扰次之,而水下机械手运动搅水引起的水动力甚微。     

Nanoscale surface deformation inspection using FFT and phase-shifting combined interferometry

In this paper, a flexible optical interferometer incorporated with both fast Fourier transform (FFT) and phase-shifting method is developed for three-dimensional (3D) testing of micro-components. Using light interference, microscopic optics, piezoelectric transducer (PZT) nanoscanning and a CCD camera, the proposed system can detect deformation and surface contour in the order of nanometers. An application of the proposed technique is demonstrated using two micro-components: a micro-beam in an accelerometer and a micromirror. The resulting interference fringes that are related to the deformation and surface contour are analyzed using FFT method or three-step phase-shifting method depending on the test surface features. Experimental results show the feasibility of the proposed method for 3D deformation and surface contour measurement of micro-components.