共查询到16条相似文献,搜索用时 734 毫秒
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最小外接球法球度误差评价与实现 总被引:2,自引:0,他引:2
针对直角坐标系下球体形状的误差评价,介绍一种利用最小外接球法评价球度误差的计算方法。建立基于直角坐标系下的球度误差三维评测模型,并研究外接球体几何曲面关系,得出了利用弦线截交关系快速评价球度误差的理论。利用弦线截交关系构建最小外接球法球度误差评价的“2+1”、“3+1”、“4+1”评价模式统一体,通过两次截交产生的虚拟中心定位,可以准确确定评价点的位置,达到了快速、精确利用最小外接球法评价球度误差的目的。通过分析表明,基于弦线截交关系的最小外接球球度误差评价方法计算效率高、易于实现且具有较高的评定精度,也为球度误差评价提供一种新的方法和思路。 相似文献
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一种利用坐标测量机实现圆度误差评价的方法 总被引:6,自引:2,他引:4
针对直角坐标系下圆周截面形状误差评价,介绍了一种圆柱体截面圆度误差的测量与评定方法.在研究了圆度误差定义及测量方法的基础上,建立了基于三坐标测量机的最小外接圆圆度误差三维评测模型.利用双截面最小二乘拟合轴线调整坐标系位置,减少了位姿误差对测量结果的影响.对模型进行坐标系统一转换,使得变换后的模型能更适用于计算机数据处理.然后在坐标变换的前提下,提出了一种利用几何关系搜索最小外接圆圆心的方法,开发了相应的数据分析软件.实验和数据证明,此算法优于传统最小外接圆算法,实现了在直角坐标系下三坐标测量机对圆度误差的最小外接圆法评价. 相似文献
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在形位公差的圆度和球度误差评定方法中,最小区域法是最符合国标中定义形位误差的方法之一。针对目前基于最小区域法建立的数学模型以及相应的求解方法存在局部收敛以及求解迂回等问题,建立了圆度和球度误差评定的鞍点规划模型,并基于鞍点规划理论的最小条件建立了鞍圆和鞍球面误差求解的新算法,通过简单几何分析和有限代数计算即可确定符合最小区域法评定原则的圆度、球度误差以及相应鞍圆、鞍球面的位置和参数。相比于传统优化算法,本文提出的方法避免了优化方法对初始值的依赖性,具有较高的求解稳定性。 相似文献
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提出了一种基于回转轴法和两点法原理的高精度微球半径测量模型,实现了基于半径变化量的微球圆度评定。建立了可以分离主轴跳动误差和计算各测量点对应半径的模型。利用团队开发的基于高精度气浮转台和两个迈克尔逊干涉仪的微球圆度测量系统,对标称直径为300μm、圆度为250 nm的红宝石球的赤道圆截面进行了扫描测量。将采用所建模型测得的微球半径与采用直径算得的半径进行对比,并通过最小区域法对所测微球圆度进行评定,结果表明:所建模型与传统直径评定方法得到的微球圆度分别为280 nm和403 nm,标准差分别为2 nm和23 nm,所建微球半径测量模型准确可靠,利用所建模型和最小区域法评定出的微球圆度更加准确可靠。所建模型可以方便准确地获得被测微球的半径,可应用于微球圆度准确评定。 相似文献
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Along with the developments of manufacturing and machining technology, spherical parts with high-precision are widely applied to many industrial fields. The high-quality spherical parts depend not only on the design and machining techniques but also on the adopted measurement and evaluation approaches. This paper focuses on the minimum zone evaluation model of sphericity deviation in Cartesian coordinate system. A new method, i.e. intersecting chord method, is proposed to solve the problem of constructing 3 + 2 and 2 + 3 models of the minimum zone reference spheres (MZSP). The modelling method employs intersecting chords rather than characteristic points to construct the geometrical structure of evaluation model. Hence, the efficiency of processing data is improved without compromising the accuracy of deviation evaluation. In the modelling process, the two concentric spheres of minimum zone model are simplified as an intersecting chords structure, the virtual centre generated by the intersecting chords can be used to judge whether the searched object is the maximum object or not, which decrease the positioning error of the minimum zone centre and reduce the difficulty of constructing models. To test and verify the performances of intersecting chord method, two experiments are performed to confirm the effectiveness of the proposed method, and the results indicate that the proposed method is more trustworthy against accuracy and computation time than other methods required to achieve the same results. 相似文献
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Minimum zone evaluation of roundness deviation is a very important and complex problem in precision measurement. Along with the continuous development of precision machining technology, it has become an increasingly prominent issue of how to quickly and accurately evaluate the minimum zone roundness deviation from a large number of coordinate data. In this paper, an intersecting chord method is first proposed to realize the minimum zone model of roundness deviation with coordinate data. The new modelling method uses the crossing relationship of chords to construct the intersecting structure and the 2 + 2 evaluation model of the minimum zone roundness deviation, which can not only accurately determine the position of minimum zone centre but also greatly improve the computational efficiency of modelling process. Using the related chords and their extreme points to generate a virtual centre, this may reduce the deviation between the intersecting chords structure and the centre of the minimum zone evaluation. The proposed method makes use of the geometric relationship of chords, so the minimum zone roundness deviation can be obtained without the optimal method or the point-by-point method. The validation test of the proposed method is designed to analyze a coordinate dataset published in other literature. Comparing the proposed method with the published method, it is easy to show that the relative error between two results is less than 0.4%. Finally, an experiment is also given to indicate that the calculation accuracy and the evaluation efficiency of the proposed method achieve a satisfactory conclusion. 相似文献
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一种最小外接圆法圆度误差评价实现方法 总被引:1,自引:0,他引:1
介绍了一种在直角坐标系下利用最小外接圆法评价圆度误差的方法。提出了一种基于对称关系的最小外接圆圆心搜索思想,运用几何思想均匀分布圆心到各点的距离,达到了快速、精确评价的目的,并且实现了在直角坐标系下三坐标测量机对圆度误差的最小外接圆法评价。 相似文献
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结合轴承沟道形状误差的几何特性,提出了轴承沟道形状误差的最小二乘评定,详细阐述了利用最小二乘算法求解轴承沟道形状误差的过程和步骤。该算法采用最小二乘法拟合每条线轮廓的中心,得到一个空间圆及方程;求解空间圆与每条线轮廓所在平面的交点坐标;计算每条线轮廓上测点至所对应的每个交点的距离中最大值和最小值之差,从中找到最大极差值,即得到包容整个轴承沟道的最小二乘形状误差值。该算法简单明确,具有精度高、易于计算机程序实现、易于推广应用等特点。 相似文献