精密数控机床全工作台空间热误差补偿技术研究

发布时间：2018-07-04 13:51

本文选题：数控机床 + 热误差　；参考：《合肥工业大学》2017年硕士论文

【摘要】：高档数控机床作为国家的重要战略资源,一直是一个国家装备制造业不可或缺的工具,也是综合国力强弱的标志。影响精密数控机床精度的因素很多,其中热误差所占比重达到40~70%,因此如何有效减小热误差对高精密数控机床加工精度的影响至关重要。调研国内外科研工作者的研究现状,发现大多按照国际标准《机床检验通则第3部分:热效应测定》(ISO 230-3:2007)的规定,由机床主轴与工作台特定单点位置的热变形来表征数控机床的热特性,并根据数控机床上安置的温度传感器的测量值与工作台固定位置点的热误差进行建模补偿。本文针对数控机床工作台存在的平面度误差以及机床各部件不均衡温升产生的空间热误差对零件加工精度的影响,提出了一种机床全空间热误差补偿的解决方法。并通过对Leaderway V-450型数控机床进行实验研究,大幅提升了其加工精度。论文主要研究内容如下:1)设计开发一套测量系统,该系统基于在线检测系统,通过数控机床空转实验,可完成对全工作台空间热误差和温度信息的采集,实验后分析所测数据,验证工作台固定单点热误差建模补偿方案的缺陷。2)提出了全工作台空间热误差建模的补偿方案,在建模的过程中,采用模糊聚类对温度变量进行分类,结合灰色关联度分析筛选温度敏感点,并首先建立15个测点的多元线性回归模型,进而根据补偿时的温度值建立每个温度时刻的最小二乘曲面热误差模型。3)改进传统热误差补偿方案,将全工作台空间热误差补偿模型的建模方法及过程嵌入到补偿器中,结合温度敏感点的温度值和机床(x,y)的实时坐标值计算出该位置点的补偿值,并采用数控系统的原点偏移功能实现对机床全工作台空间Z轴轴向向误差进行在线补偿。4)通过验证实验,对全工作台空间热误差建模补偿方法与传统工作台固定单点的误差补偿方法的补偿效果进行了比对。结果显示,空间补偿模型对整个工作台热误差补偿效果均优于单点热误差补偿模型,补偿后标准差提升了45%;单次最大补偿后误差精度提升50%。
[Abstract]:As an important national strategic resource, high-grade CNC machine tool has always been an indispensable tool for a country's equipment manufacturing industry, and also a symbol of the overall national strength. There are many factors that affect the precision of precision NC machine tools, of which the proportion of thermal error is 4070, so it is very important to reduce the influence of thermal error on machining accuracy of high precision NC machine tools. By investigating the current research situation of researchers at home and abroad, we find that most of them are in accordance with the international standard, General rules for Machine tool Inspection, part 3: determination of Thermal effect (ISO 230-3: 2007), The thermal characteristics of CNC machine tools are characterized by the thermal deformation of the spindle and worktable at a specific point, and the model compensation is made according to the measured values of the temperature sensors placed on the NC machine tools and the thermal errors of the fixed position points of the worktable. Aiming at the influence of flatness error existing in the worktable of NC machine tool and the space thermal error caused by unbalanced temperature rise of each part of machine tool on the machining accuracy of parts, this paper puts forward a method to compensate the all-space thermal error of machine tool. The machining accuracy of Leaderway V-450 CNC machine tool is greatly improved. The main contents of this paper are as follows: (1) A set of measurement system is designed and developed. The system is based on the on-line detection system. Through the idle experiment of NC machine tool, it can complete the collection of the space thermal error and temperature information of the whole worktable, and analyze the measured data after the experiment. Verify the defects of the compensation scheme of fixed single point thermal error modeling of worktable (.2) A compensation scheme for space thermal error modeling of the whole worktable is proposed. In the process of modeling, fuzzy clustering is used to classify the temperature variables. The temperature sensitive points were screened by grey correlation analysis, and the multivariate linear regression model of 15 measuring points was established. Then the thermal error model of the least square surface at each temperature moment is established according to the temperature value of the compensation. (3) the traditional thermal error compensation scheme is improved, and the modeling method and process of the space thermal error compensation model of the whole worktable are embedded in the compensator. Combining the temperature value of the temperature sensitive point and the real time coordinate value of the machine tool (XY), the compensation value of the position point is calculated. And the origin offset function of NC system is used to realize the on-line compensation of Z axial error in the whole worktable space of the machine tool, and the verification experiment is carried out. In this paper, the compensation effect of space thermal error compensation method for the whole worktable is compared with that of the traditional single point fixed worktable method. The results show that the compensation effect of the space compensation model is better than that of the single point thermal error compensation model, and the standard deviation is increased by 45% after compensation, and the error accuracy is increased by 50% after the single maximum compensation.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG659

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