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提出了一种基于几何误差灵敏度的卧式数控镗床运动精度分析方法。针对典型卧式镗床进行几何误差溯源分析,确定影响机床X,Y,Z轴运动精度的21项几何误差,基于多体系统运动学理论,考虑机床各典型体间误差耦合作用机制,建立机床的空间误差模型。借助激光干涉仪对某大型卧式数控镗床进行几何误差检测试验,将检测结果输入九线法几何误差辨识模型,分离该机床的21项几何误差,并对各几何误差进行多项式拟合,据此分析该机床的空间误差场的分布特征,并针对各几何误差项进行灵敏度分析。结果表明:X,Y轴关键误差因素为位移误差,Z轴关键误差因素为直线度误差。通过对各关键因素进行精度补偿,实现该机床空间误差场分布的优化分析。对比分析表明,补偿后的空间误差场在各线性轴分布趋于均匀,最大误差从0.056 4 mm减小为0.027 8 mm,机床的空间运动精度得到明显提高。该分析方法可为此类型机床运动精度分析及空间误差补偿提供理论依据。
A motion accuracy analysis method of horizontal CNC boring machine based on geometric error sensitivity is proposed. According to the tracing of the geometric errors of the typical horizontal boring machine, the 21 geometric errors that affect the movement accuracy of the X, Y, Z axes of the machine tool are determined. Based on the kinematics theory of the multibody system, the error coupling mechanism of the typical body of the machine tool is considered, Spatial error model. With the help of laser interferometer, the geometrical error of a large horizontal CNC boring machine is tested. The test result is input into the nine-line geometric error identification model. The 21 geometric errors of the machine tool are separated and polynomial fitting is performed on each geometric error The distribution characteristics of the spatial error field of the machine tool are analyzed, and the sensitivity analysis of each geometric error term is carried out. The results show that the key error factor of X and Y axis is displacement error, and the key error of Z axis is straightness error. Through the precision compensation of the key factors, the optimization analysis of the spatial error field distribution of the machine tool is realized. The comparative analysis shows that the distribution of the compensated space error tends to be uniform along each linear axis, and the maximum error decreases from 0.056 4 mm to 0.027 8 mm. The spatial motion accuracy of the machine tool is obviously improved. The analysis method can provide theoretical basis for this type of machine tool motion accuracy analysis and space error compensation.