快速刀具伺服车削加工系统的误差建模与测量研究

发布时间：2018-04-26 10:08

本文选题：快速刀具伺服 + 多体系统　；参考：《吉林大学》2015年博士论文

【摘要】：光学自由曲面类元件基于其优越的光学性能和较小的尺寸,采用较少的元件就可获得较高的光学利用率,在新能源、工程光学等领域具有广泛的应用需求。但由于其面形几何特征非常复杂,无法采用统一的数学表达式来描述,且在应用中对其加工精度和表面质量要求也越来越高,为加工增加了困难。为此,在保障加工效率的基础上,如何提高该类元件的加工精度和表面质量成为研究的方向。基于快速刀具伺服(Fast Tool Servo,FTS)的车削方法由于其高效、精密、低成本等诸多优点,被广泛的认为是一项较具前途的加工方法。该方法不仅能够用于对光学自由曲面的加工,同时还能对存在的加工误差进行补偿,受到了广泛的关注。本文在国内外研究的基础上,对基于FTS金刚石车削加工系统的误差进行了研究。现有的对FTS车削加工的误差研究往往只是针对FTS装置或数控机床载体分别研究,而将两者结合在一起的很少。本文将FTS装置和数控机床作为一个整体进行误差研究,建立了FTS车削系统的运动链,并对运动链中的各项误差源进行了分析。不仅考虑了运动链中各子单元所存在的几何误差对系统运动部件的运动影响,还对动力学引起的误差进行了分析,并对加工系统中的关键部件机床主轴和FTS机构建立了动力学模型。基于多体系统理论,将多体系统拓扑结构的相邻体阵列描述与传统的齐次坐标变换理论相结合,对FTS车削加工系统建立了综合的误差模型。根据多体系统理论,对拓扑结构中的相邻体间阵列进行了描述;结合齐次坐标变换理论,对多体系统相邻体间的理想运动及其特征进行了数学描述。通过对相邻体间的误差运动进行变换,描述了体间的实际运动情况及其特征。将FTS车削加工系统运动链中各项误差源作为参数,考虑理想和实际的静止与运动误差特征,建立了FTS车削加工系统的综合误差模型。借助对X轴导轨和主轴误差的测量数据,对机床导轨和主轴误差对刀具相对工件综合误差的影响进行了分析。在加工系统中,平动轴是最为关键的运动部件之一,平动轴的各项误差元素也是重要的误差来源,直接影响加工系统的加工精度。在对激光干涉仪测量平动II轴运动误差的原理进行分析的基础上,使用Renishaw XL-80激光干涉仪对导轨的定位误差和FTS机构的运动误差进行测量,并采用XC80环境补偿单元对定位误差的测量结果进行了补偿。为了解决平动轴测量数据中直线度与偏摆误差的耦合问题,消除测量过程中反射镜的运动误差影响,增强激光干涉仪的测量效率,提出一种基于激光干涉仪的移步测量方法。通过对初始采样点的移步进行多组测量,得到具有差分输出的测量结果,将多组测量数据进行组合并进行离散傅里叶变换,从而分离出平动轴运动产生的直线度误差和角度偏差。通过对平动轴运动过程中的角度偏差进行单独测量,并与分离结果相对比,对所提出的方法进行了有效验证。在加工系统中,主轴的回转运动误差是影响系统加工精度的一个重要因素。根据主轴回转运动的特点,间接测量不可避免的会引入由标准件的轮廓误差等影响因素。为了得到精确的主轴回转运动误差,需要对测量结果进行误差分离。本文归纳总结了三种典型的主轴回转运动的误差分离方法,通过对比确定了不同测量要求和条件下各个方法的选用。针对现有的车床主轴回转误差测量方法存在的不足,提出一种改进的主轴回转误差测量方法。采用两个位移传感器对柱形工件的面截面以及柱面螺旋线进行测量,通过分离工件柱面的轮廓误差与主轴的回转运动误差,得到了主轴运动过程中产生的径向误差和偏摆角误差。采用所提出方法对Spinner机床的主轴进行了测量,得到了主轴的径向跳动误差和偏摆误差,并对测量结果进行了分析。本文通过对FTS车削加工系统运动误差的数学建模分析,以及对各关键运动部件的参数项误差源的测量分析,为实现高效、高精度的自由曲面加工,以及对加工系统进行误差补偿提供了理论指导。
[Abstract]:Based on its superior optical performance and smaller size, optical free surface elements can obtain high optical utilization by using less components, and have wide application requirements in the fields of new energy, engineering optics and other fields. However, because of the complex geometric features of their surfaces, a unified mathematical expression can not be used to describe them, and they are applied in the application. The processing precision and the surface quality requirements are getting higher and higher, and it is difficult for processing. Therefore, on the basis of ensuring the processing efficiency, how to improve the machining precision and surface quality of the components is the direction of research. The turning method based on fast tool servo (Fast Tool Servo, FTS) is due to its high efficiency, precision, low cost and so on. Many advantages are widely regarded as a promising processing method. This method can not only be used to process optical free-form surfaces, but also compensate for the existing machining errors. This paper has studied the error of the FTS diamond turning system based on the research at home and abroad. The existing research on the error of the FTS turning processing is often only studied for the FTS device or the CNC machine tool carrier, but the two are seldom combined together. This paper studies the error of the FTS device and the CNC machine tool as a whole, establishes the motion chain of the FTS turning system, and analyses the error sources in the movement chain. It not only considers the effect of the geometric error of the subunits in the motion chain on the motion of the moving parts of the system, but also analyzes the error caused by the dynamics, and establishes a dynamic model for the spindle of the machine tool and the FTS mechanism, which is the key component of the machining system. The column description and the traditional homogeneous coordinate transformation theory are combined to establish a comprehensive error model for the FTS turning system. According to the theory of multibody system, the array of adjacent bodies in the topological structure is described, and the ideal motion and its characteristics between adjacent bodies of the multi-body system are described in mathematics with the theory of homogeneous coordinate transformation. By changing the error motion between adjacent bodies, the actual movement and characteristics between the bodies are described. The error sources in the motion chain of the FTS turning system are taken as parameters, and the ideal and actual static and motion errors are taken into consideration. The comprehensive error model of the FTS turning processing system is established. By the aid of the error of the X axis guide and the spindle error. The influence of the slideway and spindle error on the comprehensive error of the tool relative to the workpiece is analyzed. In the machining system, the translational axis is one of the most important moving parts. The error elements of the translational axis are also the important source of error, which directly affect the processing precision of the working system. On the basis of the principle of the motion error of the II axis, the positioning error of the guide rail and the motion error of the FTS mechanism are measured by the Renishaw XL-80 laser interferometer. The measurement results of the positioning error are compensated by the XC80 environment compensation unit. In order to eliminate the influence of the motion error of the reflector in the measurement process and enhance the measurement efficiency of the laser interferometer, a step measurement method based on the laser interferometer is proposed. By measuring the moving step of the initial sampling point, the measurement results with differential output are obtained, and the multi group measurement data are combined and the discrete Fu is carried out. It separates the straightness error and angle deviation produced by the movement of the moving axis. By measuring the angle deviation in the moving process of the translational axis alone, and comparing with the separation results, the proposed method is validated effectively. In the machining system, the rotation error of the spindle affects the processing precision of the system. An important factor. According to the characteristics of the spindle rotation movement, the indirect measurement will inevitably introduce the influence factors such as the outline error of the standard parts. In order to get the accurate spindle rotation error, it is necessary to separate the error of the measurement results. In this paper, three kinds of typical error separation methods for the spindle rotation motion are summarized and summarized. In contrast, the selection of various methods under different measurement requirements and conditions is determined. In view of the shortcomings of the existing lathe spindle rotation error measurement method, an improved method for measuring the spindle rotation error is proposed. Two displacement sensors are used to measure the surface section of the cylindrical workpiece and the helical line of the column surface, and the workpiece column is separated by the separation of the workpiece column. The radial error and deflection angle error produced during the spindle motion are obtained by the contour error of the surface and the rotation error of the spindle. The proposed method is used to measure the spindle of the Spinner machine tool. The radial runout error and the deflection error of the spindle are obtained, and the results of the measurement are analyzed. The FTS turning process is used in this paper. The mathematical modeling and analysis of the motion error of the system as well as the measurement and analysis of the error sources of the parameters of the key moving parts are analyzed, which provide theoretical guidance for the realization of high efficiency, high precision free surface machining and error compensation for the machining system.

【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TG51

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