共查询到19条相似文献,搜索用时 140 毫秒
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精密制造是机床发展的重要目标,精度设计和误差补偿是实现机床精密化的重要方法。基于多体系统理论,利用齐次坐标变换建立三轴立式加工中心空间误差模型;基于空间误差模型,利用矩阵微分法建立误差敏感度数学模型,并通过归一化处理,计算出几何误差敏感度系数,找出关键几何误差项;基于关键几何误差项,通过精度设计提高三轴立式加工中心的空间定位精度。以三轴立式加工中心的工作台中间点为例进行敏感度计算,识别出该点处的关键几何误差,并提出方法提高三轴立式加工中心的空间定位精度。 相似文献
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在给出机床关键几何误差和影响因子定义的基础上,提出了识别机床关键几何误差的新方法。以一台精密卧式加工中心为例,利用多体系统理论建立了机床几何误差与综合误差的映射关系模型,通过计算和比较影响因子,最终识别出16项影响机床精度的关键几何误差。示例表明:该方法可以有效地识别出对机床综合空间误差影响较大的几何误差因素,从而为合理经济地进行精度设计和控制提供重要的理论依据。 相似文献
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由机床几何误差复合而成的空间误差是影响加工精度的主要因素。以提高数控机床加工精度为研究目的,提出了一种基于旋量理论的机床空间误差预测及其验证技术。首先,借助旋量指数积建立了机器人末端实际位形旋量指数积数学模型,通过分析了机床21项几何误差并结合运动链拓扑搭建了机床完备模型;进而,以传统辨识方法识别了21项几何误差,输出机床空间误差预测结果;最后,开展了基于ISO230-6的体对角线实验值与模型预测值对比验证实验。实验结果表明四条体对角线实验测量值与模型预测值符合程度较高,有效验证了基于旋量理论的卧式加工中心空间误差预测分析方法正确性及合理性。 相似文献
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为了提高复合数控机床的加工精度,研究了机床的几何误差建模及灵敏度分析。以CHD-25型9轴5联动车铣复合数控机床为对象,介绍基于多体系统运动学理论的机床几何误差建模方法,模型涉及37项几何,分别对37项几何误差进行了误差灵敏度分析。通过计算与分析误差灵敏度系数,最终识别出影响机床加工精度的关键性几何误差,为复合数控机床的设计提供有效的理论依据。 相似文献
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范晋伟齐国超陶浩浩贾鑫李相智 《制造技术与机床》2018,(7):75-79
基于多体理论与齐次坐标变换,对五轴数控机床进行误差分析和加工精度建模。以XKAS2525型五轴双墙龙门数控机床为研究对象,根据机床结构和关键零部件的装配关系,分析机床各项几何误差,建立各个关键零部件的子坐标系和体间特征矩阵,系统完整地建立机床的加工精度模型,为后续的精度设计工作奠定基础。 相似文献
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《制造技术与机床》2019,(4)
针对三轴义齿雕铣机在加工过程中存在空间误差较大、加工精度较低等缺点,提出了一种对空间误差实施解析与补偿的新方法。首先分析机床拓扑结构,利用多体系统理论确定机床低序体阵列和运动学约束链,建立空间误差模型。然后对三轴雕铣机的各项几何误差进行测量并求解其空间误差值,分别计算各项几何误差相对于机床空间误差的相关性系数,以辨识对空间精度影响较大的重要几何误差分量。最后利用线性回归模型建立空间误差与位置的隐射函数,以便建立空间误差补偿模型。以z轴为例,对所建立的误差补偿模型进行实验验证。结果表明通过补偿后z轴空间误差从1. 26 mm降低到0. 735 mm,降幅为41. 7%,义齿加工精度得到了有效的提高,可见该方法有一定的实用价值。 相似文献
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本文提出一种新的机床位置误差灵敏度分析方法。首先基于多体理论和齐次变换矩阵建立了五轴龙门机床位置误差模型。其次通过截断傅里叶技术来表征与位置有关的几何误差参数,每个误差参数对位置误差的灵敏度值可表示为其傅里叶幅值平方。然后归一化处理,关键的几何误差参数为第2,3,8,15和26项误差。通过与传统的Sobol法对比,仿真结果表明两种灵敏度分析方法辨识的关键几何误差相同且灵敏度值相近。此外,本文提出的灵敏度分析计算效率优于传统Sobol法。最后为了验证关键几何误差的有效性,提出了一个关于机床关键几何误差的补偿实验。实验结果表明,补偿关键几何误差后机床的加工精度提升了48%。因此,本文提出的机床位置误差灵敏度分析方法是可行的和有效的。 相似文献
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提出了工件分特征下的五轴数控机床关键几何误差分析与补偿方法,将复杂工件进行特征分解,通过灵敏度分析辨识工件分特征下的关键几何误差并补偿,从而提高工件整体加工精度。以某一复杂工件为例,首先,将其分解为平面、斜面、圆柱和圆锥台四个典型特征;然后,基于灵敏度分析分别辨识出各典型特征对应的关键几何误差;最后,分特征地进行误差补偿。在AC双转台五轴数控机床上进行了实验验证,实验结果表明,辨识得到的关键几何误差灵敏度系数之和占比均大于90%,补偿后工件四个典型特征的加工精度提高了20%~30%。研究结果表明,所提方法能有效辨识不同工件分特征下的关键几何误差,从而提高复杂工件的加工精度。 相似文献
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MODELING AND COMPENSATION TECHNIQUE FOR THE GEOMETRIC ERRORS OF FIVE-AXIS CNC MACHINE TOOLS 总被引:7,自引:0,他引:7
Wang ShuxinYun JintianZhang ZhifeiLiu YouwuZhang QingSchool of Mechanical Engineering Tianjin University Tianjin China 《机械工程学报(英文版)》2003,16(2):197-201
One of the important trends in precision machining is the development of real-time error compensation technique. The error compensation for multi-axis CNC machine tools is very difficult and attractive. The modeling for the geometric error of five-axis CNC machine tools based on multi-body systems is proposed. And the key technique of the compensation-identifying geometric error parameters-is developed. The simulation of cutting workpiece to verify the modeling based on the multi-body systems is also considered. 相似文献
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M. Sharif Uddin Soichi Ibaraki Atsushi Matsubara Tetsuya Matsushita 《Precision Engineering》2009,33(2):194-201
Kinematic errors due to geometric inaccuracies in five-axis machining centers cause deviations in tool positions and orientation from commanded values, which consequently affect geometric accuracy of the machined surface. As is well known in the machine tool industry, machining of a cone frustum as specified in NAS979 standard is a widely accepted final performance test for five-axis machining centers. A critical issue with this machining test is, however, that the influence of the machine's error sources on the geometric accuracy of the machined cone frustum is not fully understood by machine tool builders and thus it is difficult to find causes of machining errors. To address this issue, this paper presents a simulator of machining geometric errors in five-axis machining by considering the effect of kinematic errors on the three-dimensional interference of the tool and the workpiece. Kinematic errors of a five-axis machining center with tilting rotary table type are first identified by a DBB method. Using an error model of the machining center with identified kinematic errors and considering location and geometry of the workpiece, machining geometric error with respect to the nominal geometry of the workpiece is predicted and evaluated. In an aim to improve geometric accuracy of the machined surface, an error compensation for tool position and orientation is also presented. Finally, as an example, the machining of a cone frustum by using a straight end mill, as described in the standard NAS979, is considered in case studies to experimentally verify the prediction and the compensation of machining geometric errors in five-axis machining. 相似文献
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This paper presents a method to identify the position independent geometric errors of rotary axis and tool setting simultaneously using on-machine measurement. Reducing geometric errors of an ultra-precision five-axis machine tool is a key to improve machining accuracy. Five-axis machines are more complicated and less rigid than three axis machine tools, which leads to inevitable geometric errors of the rotary axis. Position deviation in the process of installing a tool on the rotary axis magnifies the machining error. Moreover, an ultra-precision machine tool, which is capable of machining part within sub-micrometer accuracy, is relatively more sensitive to the errors than a conventional machine tool. To improve machining performance, the error components must be identified and compensated. While previous approaches have only measured and identified the geometric errors on the rotary axis without considering errors induced in tool setting, this study identifies the geometric errors of the rotary axis and tool setting. The error components are calculated from a geometric error model. The model presents the error components in a function of tool position and angle of the rotary axis. An approach using on-machine measurement is proposed to measure the tool position in the range of 10 s nm. Simulation is conducted to check the sensitivity of the method to noise. The model is validated through experiments. Uncertainty analysis is also presented to validate the confidence of the error identification. 相似文献
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数控机床制造精度的优化分配方法 总被引:2,自引:0,他引:2
精度设计是机床设计中的重要一环,包含精度分析和精度分配两个互逆问题,其中精度分配是指在满足给定整体精度的基础上优化设计机床组成零部件的精度。几何误差对机床加工精度有关键性的影响,采取一种新的思路来进行精度分配。采用多体系统理论对机床误差建模,进而得到用于精度分配的模型,用线位移误差近似表示角位移误差和垂直度误差;以制造成本最低和满足加工精度为目标,利用Matlab和遗传算法优化误差参数,对机床零部件进行精度分配;最后验证表明此方法能使性能和经济性得到较好的协调。 相似文献