摘要
轮廓误差是评价五轴数控机床加工性能的重要指标。为了计算和预测轮廓误差,提出了一种基于Simulink数字孪生(SDT)模型的计算和预测五轴机床轮廓误差的方法。首先,以“S”形试件为研究对象,利用UG软件得到了加工G代码和刀位信息,利用刀位点和刀具的几何关系计算得到了加工表面点云,同时考虑了刀具轨迹和刀轴姿态,根据NURBS曲面拟合方法,拟合出了理想和实际加工表面;然后,利用霍斯豪夫距离计算了预测点和实际加工表面的法向距离,即轮廓误差,同时在欧式空间中预测了非可展直纹面加工中出现的过切、欠切和奇异点缺陷,轮廓误差在69μm到241μm之间,表明实际加工特征和数字孪生模型预测结果一致;最后,利用残差平方和来评价拟合精度,计算了目标面平均轮廓误差。研究结果表明:五轴轮廓误差计算精度提高了37%,与雅克比矩阵方法相比,计算效率提高了25%,正反向计算误差在±0.6μm之内,证明了该方法的有效性。该结果可为后续机床数字孪生建模、轮廓误差计算与补偿提供一定的参考。
The contour error is an important indicator for evaluating the machining performance of five-axis CNC machine tools.In order to calculate and predict contour errors of five-axis machine tools,a method based on Simulink digital twin(SDT)modeling was proposed.Firstly,taking the"S"shaped workpiece as the research object,the processing G code and tool position information were obtained by using UG,and the processing surface point cloud was calculated by utilizing the geometric relationship between tool position points and tools,considering tool trajectory and tool axis attitude.Ideal and actual processing surfaces were fitted based on NURBS curve fitting method.Then,the normal distance between the predicted point and the actual machined surface was calculated by using the Hoshoff distance,it was the contour error.At the same time,the over cut,under cut and singular point defects in the processing of non-developable ruled surface were predicted in the European space,and the contour error was 69μm to 241μm,indicating that the actual processing characteristics were consistent with the prediction results of the digital twin model.Finally,the residual sum of squares was utilized to evaluate the fitting accuracy,calculating the average contour error of the target surface.The research results demonstrate that the precision of five-axis contour error calculation is improved by 37%,with a 25%increase in computational efficiency compared to the Jacobian matrix method.The forward and reverse calculation errors are within±0.6μm,validating the effectiveness of the proposed method,which can provide a certain reference for subsequent machine tool digital twin modeling,contour error computation and compensation enhancement.
作者
于志献
陈光胜
YU Zhixian;CHEN Guangsheng(School of Mechanical Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China)
出处
《机电工程》
CAS
北大核心
2024年第10期1723-1733,共11页
Journal of Mechanical & Electrical Engineering
基金
国家重点研发计划项目(2017YFB1104600)。
关键词
五轴机床轮廓误差
Simulink数字孪生模型
刀具轨迹
刀轴姿态
霍斯豪夫距离
圆柱铣刀侧铣切削
profile error of five-axis machine tools
Simulink digital twin(SDT)model
tool trajectory
tool axis attitude
Hausdorff distance
side milling of cylindrical milling cutter
