大型龙门机床的直线度误差建模及误差补偿

摘要

To decrease the straightness errors and improve the accuracy of machine tools, a spatial straightness error modeling which is based on B-Spline curves is presented. Experiments are carried out on a machine tool to obtain six serials of straightness errors by laser interferometer and a space straightness error modeling is obtained by applying the B-Spline method. Compensation is implemented by applying the error compensation system which utilizes the external mechanical origin offset function of Fanuc to impute the compensation data into CNC. Compared with the polynomial model and the interpolation model, the B-Spline model is proved to be of high accuracy. In addition, the straightness errors of the machine tool are deceased by more than 90%compared with no compensation, the machine accuracy is efficiently improved.%为减小大型龙门数控机床空间直线度误差,提高国产数控机床加工精度,提出基于B样条曲线的空间直线度误差模型及其补偿方法. 使用激光干涉仪分别检测三轴龙门数控机床6个方向的直线度误差,应用B样条方法建立空间直线度误差数学模型. 利用数控系统外部机械原点偏移功能,应用自主研发的误差实时补偿系统并依据基于B样条曲线的空间直线度误差数学模型,实现对大型龙门数控机床的空间直线度误差补偿. 采用两轴联动补偿切削导轨面的方法进行试验,并与多项式模型和斜线插补模型进行对比,结果表明:B样条模型补偿后的导轨直线度最优,检测的导轨各方向直线度误差均减小90%以上,显著提高了大型龙门数控机床加工精度.