大行程三坐标测量机全局空间运动误差标定关键技术及实验研究

The calibration of kinematic error is an important way to improve the motion accuracy of equipment, however at present, the calibration for kinematic error of large scale coordinate measuring machine is generally lack of efficient technical means. There are three main problems in traditional calibration method for kinematic error of large scale coordinate measuring machine, that is tedious measuring process, long measuring period and high measuring cost. Therefore, this research focuses on the advantages of linkage error information measurement technology based on ball bar circular test, and then apply them to the volumetric linkage error measurement in a large range in order to realize an efficient and economical calibration for whole volumetric kinematic error of large scale coordinate measuring machine. Firstly, the calibration methods for volumetric linkage error are researched, and a mathematical model of terminal kinematic error of measuring machine based on the whole volumetric linkage error information is established. Secondly, the measuring method of large range whole volumetric linkage error information with high efficiency and low cost is studied. Finally, taking the large scale coordinate measuring machine developed in our laboratory as calibration object, designing and building an experiment device to measure its whole volumetric linkage error, as well as testing and evaluating its motion accuracy after the calibration. This study will enrich the calibration technology for kinematic error of large equipment institution and provide new method and reference theory for volumetric linkage error measurements in large range with simplification, high efficiency and low cost.

运动误差标定是提高装备运动精度的重要途径，而目前针对大行程三坐标测量机的运动误差标定普遍缺乏高效的技术手段。传统标定方法对大行程三坐标测量机运动误差的测量主要存在测量工序繁琐、测量周期长以及测量成本高等问题。为此，本研究借助基于球杆仪循环测试的联动误差信息测量技术的优势，将其改进应用到大范围空间联动误差的测量中，以实现大行程三坐标测量机全局空间运动误差标定的高效性和经济性为目标，首先研究大行程三坐标测量机空间联动误差标定方法，建立基于全局空间联动误差信息的测量机端部运动误差数学模型；其次研究大范围全局空间联动误差信息高效、低成本的测量方法；最后以本实验室研制的大行程三坐标测量机为标定对象，自行设计搭建该测量机全局空间联动误差信息测量的实验装置，并对标定后测量机的运动精度进行检测和评估。本研究将丰富大型装备机构的运动误差标定技术，为实现简化、高效、低成本的大范围空间联动误差测量提供新的方法。

随着制造技术的发展，零部件朝着大尺寸，复杂面形，高精度等方向发展，这使得大行程三坐标测量机不可或缺，同时也对大行程三坐标测量机的检测精度提出了更高的参数要求。然而，目前大行程三坐标测量机的误差标定仪器主要是激光干涉仪和激光跟踪仪，它们在标定过程中存在使用成本高、测量周期长、需配专用调试人员等不足，无法得到广泛应用。鉴于此，本研究创新性地提出了一种基于球杆仪循环联动误差测量实现三坐标测量机局部空间误差识别与补偿的方法，并通过拼接数据处理将球杆仪多个位置的误差数据进行整合，最终实现大行程三坐标测量机的全局空间误差标定，主要研究内容及成果包含以下部分：.基于球杆仪联动误差测量原理，分析球杆仪的联动误差测量模型；分析了球杆仪测量数据存在中心偏置误差的原因，建立中心偏置误差补偿算法；提出利用最小二乘圆心拟合和迭代逼近两种方法对联动误差中包含的中心偏置误差量进行识别。.基于中心偏置补偿后的球杆仪联动误差测量模型，提出了3种平面联动误差分离方法。通过仿真分析三种分离方法，角度分离法忽略了球杆仪联动误差测量过程中的转角误差，导致分离所得误差量与原始误差数据存在较大偏差，而联立方程法和激光干涉仪辅助法的误差分离结果与原始数据偏差分别小于2.5μm和0.4μm。.在全局空间误差标定方法上，提出了球杆仪多位置局部区域联动误差测量方式，结合重叠区域具有相同误差信息，分别提出了全局联动误差拼接分离法和局部联动误差分离拼接法两种误差拼接数据处理方法。以实验室自行研制的三坐标测量机为标定对象，运用全局联动误差拼接分离法实现XY平面全局联动误差标定后，XY平面的联动误差为24.1μm；用局部联动误差分离拼接法进行XY平面全局联动误差标定后，XY平面的联动误差为20.8μm。因Z轴行程限制，在XZ、YZ平面进行半径100mm的局部误差标定，标定后，三坐标测量机XZ平面的最大圆度误差由76.7μm降低至8.9μm，YZ平面的最大圆度误差由64.9μm降低至9.8μm。