基于轴间双向耦合的五轴联动机床几何误差渐近辨识补偿方法研究

Five-axis machine tool with advantages of high accuracy and efficient machining is the most important processing equipment of modem manufacturing industry. Geometric error is one of the main sources of error in five-axis machining. Since the identification and compensation of geometric errors is an effective and convenient approach to improve the accuracy of a five-axis machining, it has received widespread attention. Geometric errors have the characteristics of small scale and multi-dimensional, so that the identification methods usually focus on either the precise measurement of one error component or the complete measurement of all error components. However, there is no identification method both has pertinence and comprehensiveness and this brings difficulties on the geometric errors measurement of five-axis machine tools. This project proposes an identification and compensation method of five-axis machine tool geometric errors based on axes bi-directional coupling. Considering the bi-directional coupling effect among each axis, especially the reverse-coupling to establish the five-axis machine tool space error model. Based on the study of geometric error multiplication method and geometric error model characteristic points reconstruction method, this project implements the single-setup multiplicative identification of five-axis machine tool geometric errors. With utilization of measurement results in each step, machine tool spatial error model can be gradually compensated.

五轴联动机床具有高效、高精加工等特点，是现代制造业中最重要的加工设备之一。受制造装配精度影响，五轴联动机床存在固有的几何误差。通过测量和补偿，减小几何误差的影响，提高加工精度一直是国内外研究热点。相对于三轴联动机床的21项误差，五轴联动机床引入了旋转轴，其几何误差分量多达40多项，且呈现很强的非线性耦合关系，其测量和补偿更加困难。现有建模方法仅考虑轴间正向耦合，采用“先测后补”方式，且需多次装夹才能完成，操作繁琐费时。本项目提出一种基于轴间双向耦合的五轴联动机床几何误差渐近式倍增测量及补偿方法。基于五轴联动机床轴间双向耦合，建立五轴联动机床空间误差模型；研究几何误差倍增方法及几何误差模型特征点阵重构方法，实现五轴联动机床几何误差一次装卡倍增测量；利用各几何误差测量结果，“边测边补”、一气呵成实现所有几何误差的渐近式补偿。

五轴联动机床具有高效、高精加工等特点，是现代制造业中最重要的加工设备之一。受制造及装配精度的影响，五轴联动机床存在固有的几何误差。通过测量和补偿，减小几何误差的影响，提高机床加工精度一直是国内外研究热点，但由于五轴联动机床引入了两个转动轴，几何误差数量更多，且在测量补偿中呈现出复杂的耦合关系，因此测量和补偿更加困难。本课题基于上述现状，针对五轴联动机床几何误差测量及补偿方法完成了以下研究：.（1）分析了五轴联动机床的三种基本结构，梳理了几何误差来源、定义、耦合关系及表征方法，依此建立了五轴联动机床理想、实际成型函数，并进一步建立了以几何误差为参数的五轴联动机床空间误差模型；（2）利用旋转轴的转动以及单测点原则，提出了几何误差的倍增方法，并分别用触发式测头-标定球、试件加工-三坐标测量仪、试件加工-激光位移传感器三种实现途径进行了验证，提高了几何误差的测量精度；（3）研究了基于低序体多位姿阵列的高序体几何误差模型特征点阵生成机理，使得测量设备能够在待测轴同一位姿下自动构造几何误差模型特征点阵，为实现一次装卡高效高精几何误差的测量提供了理论依据；（4）提出了一种基于轴间拓扑关系的几何误差渐近补偿方法，按照机床运动链中距离切削点由近及远的顺序求解平动轴及转动轴补偿指令，避免了刀具位置误差补偿算法中的迭代过程，提高了误差补偿效率；（5）依据上述研究，开发了一种几何误差补偿软件，可完成测量轨迹规划、测量数据导入、几何误差辨识以及补偿文件生成的功能。.本课题围绕五轴联动机床空间几何误差建模、解耦、测量及补偿策略展开研究，提出五轴联动机床渐近辨识和补偿方法，为五轴联动机床的几何误差运动学标定提供了新的思路和有益探索。