【作者】 崔建文；

【导师】 唐文彦；

【作者基本信息】 哈尔滨工业大学 ， 仪器科学与技术， 2007， 博士

【摘要】 微细轴、引线等细圆柱体广泛应用于航空、航天、军工及民用领域,对其直径精密而高效的测量能够提高这类零件的精度,进而提高使用这类零件的仪器或武器的性能、降低次品率和生产成本、增加生产效率、减小资源消耗,因此对细圆柱体直径测量技术进行研究有重要意义。本文以提高激光衍射法细圆柱体直径测量精度为主要目的,在查阅大量国内外文献,详细分析国内外的研究现状的基础上,主要完成了以下几方面的研究内容:首先,提出了一种衍射法测量细圆柱直径的矢量模型。该模型以半无限大金属屏的矢量衍射场和基于电磁场理论的巴俾涅原理为理论基础,充分考虑入射光束的偏振特性,包括E偏振下的衍射模型和H偏振下的衍射模型。实验结果表明使用矢量模型测量细圆柱体直径可以获得更高的测量精度。其次,研制了一套基于激光衍射的细圆柱体直径测量系统。测量系统选用半导体激光器(LD)作为光源,通过偏振片产生线偏振光,面阵CCD作为衍射花样接收器。系统的测量范围是0.05~0.5mm。系统研究了细圆柱体实测衍射花样的形成。针对细圆柱体理想衍射花样和实测衍射花样的差异,从白噪声、光源的高斯特性、细圆柱体空间位置及外界扰动和焦点光斑等四个方面研究了实测衍射花样。详细分析了各个因素对实测衍射花样的影响,并对各个影响因素进行了相应的计算机仿真。仿真实验与细圆柱体的实测衍射花样进行了比对,表明理论分析结果的正确性。设计了一种细圆柱体有效衍射信息的零相位滤波算法。根据细圆柱体衍射花样处理的特殊性,在分析常用滤波算法的基础上,确定并设计了用于零相位滤波算法的切比雪夫Ⅱ型滤波器。对零相位滤波器、中值滤波器和平均值滤波器进行了实测比对和仿真实验比对。比对结果证明该算法可以获得更理想的滤波效果。然后,对线阵CCD和面阵CCD在细圆柱体直径测量中的应用进行了分析,研究了从面阵CCD接收的细圆柱体衍射花样中提取有效衍射信息问题。为实现准确提取衍射特征信息的位置,对零相位滤波后有效衍射信息使用三次样条插值进行了亚像素细分。提出了一种加权的提取算法。该算法使用全花样衍射信息,克服了使用部分衍射信息提取衍射特征信息的弊端。最后,实测了衍射测量模型的两个重要参数,并对不同直径的细圆柱体进行了测量,分析了衍射角对测量结果的影响、不同模型的原理误差和测量系统的相对测量误差。测量结果表明本文研究的测量系统的相对测量误差是0.4%。更多还原

【Abstract】 Thin cylinders, such as micro-shaft and leg wird, are widely used in the fields of aviation, astronavigation, military industry and civil industry. The accuracy of manufacture of these parts can be increased by precison and high efficiency measurement of their diameters. So do the performance and producing efficiency of instrument or weapon, in which these parts are used. At the same time the defective rate, production costs and resource consumption can be also decreased. So the research on diameter measurement technique of thin cylinder is very important.In this dissertation, to impove the measurement accuracy of thin cylinder diameter is the primary object. A large quantity of references is consulted and the current situation of domestic and exernal research are studied. The main content and innovative achievements of this dissertation are as follows:At firs, the vector model of thin cylinder diffraction has been proposed. This model which considered the polarization character of incident light is on the basis of two theories: the vector diffraction field of half-infinite metal screen and Babinet’s principle. And it consists of the diffraction model of E polarized incident field and H polarized incident field. Experiment result shows that the measurement of thin cylinder diameter can achieve higher measurement accuracy by vector model.Secondly, the measurement system of thin cylinder diameter by laser diffraction is developed. Semiconductor laser (LD), polarizing film and area CCD is used in the measurement system. LD is taken as incident source and polarizing film is as producer of linearly polarized light and area CCD is as receiver of diffraction pattern. The measurement range is from 0.05mm to 0.5mm.Thirdly, the formation of actual diffraction pattern of thin cylinder is studied systematicly. The difference between ideal diffraction pattern and that of actual measurement is considered and the actual diffraction pattern is studied on four aspects, such as white noise, characteristic of Gauss beam of LD, , spatial position and disturbance of thin cylinder and focal spot. The influence to actual diffraction pattern of all the influencing factors is studied in detail and the corresponding simulation of every influencing factor is also done. Then the simulation is compared with the actual diffraction pattern and they prove that the study is right.Forthly, the zero-phase filtering algorithm has been proposed to process the effective diffraction information. Considering the particularity of processing diffraction pattern of thin cylinder, the ChebyshevⅡfilter is taken as the filter of zero-phase filtering algorithm based on analysis of usual filtering algorithm. At last, comparison among zero-phase filter, median filter and mean filter is done by simulation and actual measurement. Experiment result shows that it can achieve better filtering effect.Application of linear CCD and area CCD is analyzed in measurement of thin cylinder diameter and the problem that how to pick up effective diffraction information from diffraction pattern received by area CCD is studied. To pick up characteristic diffraction information accurately, the effective diffraction information filtered by zero-phase filter is subdivided by interpolating cubic spline function.Fifthly, a new weighted algorithm has been proposed. This algorithm is more rational by total effective diffraction information, which overcomes the shortage of picking up characteristic diffraction information by part effective diffraction informationFinaly, two important parameters of diffraction model and several thin cylinders of different diameters are measured. Then the influence of diffraction angle to measurement result is analyzed, so did theoretical error between different diffraction models and relative measurement error. Measurement result shows that the relative error of this measurement system is 0.4%.更多还原