【作者】 刘力双；

【导师】 王宝光；

【作者基本信息】 天津大学 ， 测试计量技术及仪器， 2006， 博士

【摘要】 随着机械加工行业的高速发展,数控加工中心已得到广泛应用。刀具预调测量仪(对刀仪)是通过测量刀具的切削点位置、角度和圆弧半径等参数,对刀具进行预调整的测量仪器。要保证数控加工中心的加工精度,刀具预调测量仪是其必备仪器。电子摄像式刀具预调测量仪是以计算机视觉检测技术为基础,集光、机、电和精密测量技术为一体的精密测量仪器,具有较高的精度和自动化水平。目前此类产品只有国外厂家生产,国内生产的刀具预调测量仪仍然为光学投影式,人眼瞄准测量、测量速度低等缺点使其不能满足高精度、高效率的要求。本课题“电子摄像式刀具预调测量仪的研究”目的就是开发该仪器。论文主要研究内容和工作如下:1.完成了刀具预调测量仪的机械系统、视觉系统和软件系统的设计与实现,并对仪器进行了整机检定,分析了各部分误差来源。仪器精度达到国家标准,经实验多次测试及用户使用验证,仪器工作稳定、性能良好。2.对视觉检测中的图像处理技术进行了深入研究,包括图像预处理、边缘检测、轮廓跟踪、刀具类型识别和图像几何参数计算等,并通过实验研究选择合适的图像处理算法。在分析CCD成像特性的基础上,提出了一种对测量图像进行快速亚像素边缘定位算法,该算法具有精度高、速度快的特点。3.提出了一种新的二维图像测量系统标定方法,并成功应用在刀具预调测量仪上。这种方法采用单个特征点的靶标件,标定时保持靶标件不动,移动视觉系统并通过光栅尺或双频激光干涉仪测量获得视觉系统的移动距离,从而获得多组标定特征点,求出标定参数。该方法靶标件加工简单,易于实现现场标定。本文对成像系统的畸变进行了研究,提出了分区线性畸变校正的方法。4.对图像测量系统的调焦评价函数进行了系统研究,不但从理论上分析了调焦评价函数的灵敏度与被测工件空间频率、聚焦区域大小的关系,还通过实验验证了理论分析的正确性,并根据实验结果确定了刀具预调测量仪的调焦评价方法。更多还原

【Abstract】 With the rapid development of mechanical fabrication industry, the numerical control processing center has been widely used by manufacturers. The TPMM (Tool Presetting and Measuring Machine) is used to preset tools by measuring the cutting point coordinates, angles, radius parameters of tools. To ensure the processing precision TPMM is crucial in the numerical control processing.The TPMM based on CCD imaging founds its technical base on machine vision inspection. It integrates applied optics, electronics technology and precision measurement technology, so that it possesses high precision and automation. Most such commercially available products as TPMM are made by foreign manufacturers, the homemade TPMM are all of optical projection mode carried out by human sight aiming; the optical projection mode suffers from subjective errors and is time consuming, so that precision and efficiency of the measurement are compromised. The project“Research of Tool Presetting and Measuring Machine Based on CCD Imaging”is to develop such an instrument.The main research works are listed as follows.1. The design and implementation of the mechanical system, the vision system and the software system of the TPMM are accomplished. The overall test of the instrument is performed. The error sources of all kind are analyzed. The precision of the instrument conforms to the national standard. The performance of the TPMM is tested to be high through experiments and custom applications.2. This thesis investigates deeply into image processing techniques in image measuring system, which includes: image pre-processing, edge detection, contour tracing, tool identification, characteristic parameter extraction and so on. The algorithms are carefully chosen and optimized through experiments. Based on the analysis of imaging characteristics of CCD, a sub-pixel edge locating algorithm is introduced in this work, and its virtues of high speed and high-accuracy are demonstrated.3. This thesis puts forward a new calibration method for two-dimensional image measuring system. Experimental results show that the novel method can improve the precision and efficiency of the TPMM. In this method, a target with single characteristic point is adopted. The target is kept still when calibration is performed,更多还原