直齿圆柱齿轮渐开线齿廓的结构光视觉测量技术

发布时间：2018-05-02 21:07

本文选题：结构光视觉 + 直齿圆柱齿轮　；参考：《吉林大学》2014年博士论文

【摘要】：结构光视觉技术以光学和电学中的物理现象为基础，获取并处理被测物体表面与结构光相接处的图像来重构被测物体的三维几何信息，可主要用于复杂曲面或自由曲面的三维测量。将结构光视觉技术应用于机械工业中的零件尺寸测量，具有非接触、速度快、自动化程度高等优点，因此结构光视觉技术在机械工业领域中的应用越来越受到人们的关注。齿轮是机械工业中一种重要的传动零件，直齿圆柱齿轮的应用尤为广泛，随着对齿轮质量的要求越来越高，对齿轮的测量也提出了更加严格的要求。测量精度的发展影响着制造技术的提高，，因此研究更加先进的齿轮测量技术对齿轮制造技术的整体提高有着非常重要的推动作用。当齿轮存在较大的齿形误差时，工作齿形已不是正确的渐开线齿形，其啮合点的运动理论上已经不再符合齿轮基本定律，导致瞬时传动比发生变化，影响齿轮传动的工作平稳性。因此，齿轮齿形误差的测量在齿轮各项参数的测量中尤为重要。本文建立以CCD摄像机、光学镜头、半导体激光器以及计算机为主要组成部分的结构光视觉测量系统，利用直齿圆柱齿轮的几何特征，提出了一种基于结构光视觉技术的齿轮渐开线齿形误差的测量方法。首先，本文分析了结构光视觉模型，该模型分为两部分：对于CCD摄像机的成像模型，基于小孔成像原理的假设，建立非线性的坐标转换关系，并利用经典的两步标定法对模型中各参数进行标定；对于结构光光平面的参数模型，在分析了传统标定法的基础上，提出了基于全局参数的改进标定法，优化了整个系统的参数变量，有效的提高了结构光视觉系统的标定精度。最后，结构光系统标定实验表明，采用6幅共面标靶图像，将光条宽度控制在5个像素左右可以得到最佳的标定结果。其次，本文根据被测直齿圆柱齿轮的几何特征，建立了渐开线齿廓的测量模型。针对测量时结构光光平面与齿轮回转轴线不垂直的问题，建立了基于回转轴线方向的伪光平面，并将通过结构光视觉系统重构的目标点投影到这个平面上，在垂直于回转轴线的方向上形成一条渐开线。为了简化齿形误差的计算，本文在伪光平面上建立局部坐标系，将被测点的三维坐标转换成光平面上的二维坐标，并在此二维直角坐标系下，按坐标法给出了基圆半径和渐开线齿形误差的计算方法。为了提高结构光视觉系统测量的分辨率，从图像中获取光条中心点的亚像素位置是必要的。本文分析了几种亚像素光条中心点检测方法。针对经典的Steger光条中心点检测方法，讨论了各参数的最优值选择。针对传统评价方法的不足，本文提出了一种基于量块尺寸的精度评价方法，将实际尺寸测量误差作为精度评价准则，更符合测量的实际要求。最后，通过测量实验验证了本文提出的直齿圆柱齿轮渐开线齿形误差的结构光视觉测量方法的精度。实验分为测量基圆误差和测量渐开线齿形误差两部分。实验结果表明，结构光视觉测量系统平台的安装位置、齿轮的齿数、结构光光平面与齿轮横截面的夹角对测量精度无明显影响。齿轮的模数越大，本文的测量方法的测量精度也越高。本文的研究工作对发展结构光视觉测量技术的工程应用具有一定的意义。
[Abstract]:Based on the physical phenomena in optics and electricity , the structured light vision technology is used to reconstruct the three - dimensional geometric information of the object under test and to reconstruct the three - dimensional geometric information of the object to be measured . It can be applied to the measurement of the dimension of the part in the mechanical industry . It has the advantages of non - contact , high speed , high degree of automation , etc . The application of the structured optical vision technology in the field of mechanical industry is more and more attention .

Gear is an important transmission part in the mechanical industry , the application of spur gear is especially wide . As the requirement of gear quality is more and more high , the measurement of gear is more strict . The development of measurement precision affects the improvement of manufacturing technology . Therefore , it is very important to study the more advanced gear measurement technology to improve the overall improvement of gear manufacturing technology .

In this paper , the measurement of gear tooth profile error is very important in the measurement of gear parameters .

Firstly , the structure light vision model is analyzed , and the model is divided into two parts : for the imaging model of CCD camera , based on the assumption of pinhole imaging principle , a nonlinear coordinate conversion relationship is established , and the parameters in the model are calibrated by using the classical two - step calibration method ;
On the basis of analyzing the traditional calibration method , the parameter variable of the whole system is optimized , and the calibration accuracy of the structure optical vision system is improved effectively . Finally , the calibration experiment of the structure light system shows that the optimal calibration result can be obtained by controlling the width of the light bar around 5 pixels by using six coplanar target images .

In order to simplify the calculation of the tooth profile error , a local coordinate system is established on the pseudo light plane , and the three - dimensional coordinates of the measured point are converted into two - dimensional coordinates on the optical plane .

In order to improve the resolution of the measurement of the structure optical vision system , it is necessary to obtain the sub - pixel position of the center point of the light bar from the image .

In the end , the accuracy of the structured light vision measurement method for the involute profile error of the straight - tooth cylindrical gear is verified by the measurement experiment . The experiment is divided into two parts : measuring the base circle error and measuring the tooth profile error of the involute gear . The experimental results show that the angle between the installation position of the platform of the structured light vision measuring system , the number of teeth of the gear , the plane of the structured light and the cross section of the gear has no obvious influence on the measurement accuracy . The larger the modulus of the gear , the higher the measurement accuracy of the measurement method in this paper .

The research work of this paper has certain meaning to the engineering application of the development structure light vision measurement technology .

【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TH132.41

【参考文献】