To deal with over-shooting and gouging in high speed machining,a novel approach for velocity smooth link is proposed. Considering discrete tool path,cubic spline curve fitting is used to find dangerous points,and acco...To deal with over-shooting and gouging in high speed machining,a novel approach for velocity smooth link is proposed. Considering discrete tool path,cubic spline curve fitting is used to find dangerous points,and according to spatial geometric properties of tool path and the kinematics theory,maximum optimal velocities at dangerous points are obtained. Based on method of velocity control characteristics stored in control system,a fast algorithm for velocity smooth link is analyzed and formulated. On-line implementation results show that the proposed approach makes velocity changing more smoothly compared with traditional velocity control methods and improves producti-vity greatly.展开更多
To improve the efficiency of CNC machining,assumptive transit circular arc is used to contour two adjacent moves together on the corner to make smooth paths. The radius of transit circular arc can be adjusted with con...To improve the efficiency of CNC machining,assumptive transit circular arc is used to contour two adjacent moves together on the corner to make smooth paths. The radius of transit circular arc can be adjusted with contour accuracy,and the feed rate on the corner can be controlled through limiting the maximum feed rate of transit circular arc segment. A look-ahead algorithm for a series of moves is proposed for speed adjustment in advance,which avoids the occurrence of overload of cutting tool on the corner and reduces the servo track error of parts on the corner or of circular arc move. Equivalent trapezoidal velocity profile is used to analyze the speed of S-curve velocity profile and work out its accurate interpolation,which overcomes the disadvantage of looking up table to calculate feed rate approximately,hence high accuracy and fine surface quality can be obtained while the machining speed is high. The proposed methods can meet the requirements of real-time analysis of high-speed machining. The presented algorithm is effective and has been adopted by CNC system of newly developed high-speed milling machine.展开更多
基金This project is supported by National Hi-tech Research and Development Program of China (863 Program, No. 2002AA421150)Specialized Re-search Fund for Doctor Program of Higher Education of China (No. 20030335091).
文摘To deal with over-shooting and gouging in high speed machining,a novel approach for velocity smooth link is proposed. Considering discrete tool path,cubic spline curve fitting is used to find dangerous points,and according to spatial geometric properties of tool path and the kinematics theory,maximum optimal velocities at dangerous points are obtained. Based on method of velocity control characteristics stored in control system,a fast algorithm for velocity smooth link is analyzed and formulated. On-line implementation results show that the proposed approach makes velocity changing more smoothly compared with traditional velocity control methods and improves producti-vity greatly.
基金Sponsored by the National Excellent Young Teacher Encouragement Plan of China
文摘To improve the efficiency of CNC machining,assumptive transit circular arc is used to contour two adjacent moves together on the corner to make smooth paths. The radius of transit circular arc can be adjusted with contour accuracy,and the feed rate on the corner can be controlled through limiting the maximum feed rate of transit circular arc segment. A look-ahead algorithm for a series of moves is proposed for speed adjustment in advance,which avoids the occurrence of overload of cutting tool on the corner and reduces the servo track error of parts on the corner or of circular arc move. Equivalent trapezoidal velocity profile is used to analyze the speed of S-curve velocity profile and work out its accurate interpolation,which overcomes the disadvantage of looking up table to calculate feed rate approximately,hence high accuracy and fine surface quality can be obtained while the machining speed is high. The proposed methods can meet the requirements of real-time analysis of high-speed machining. The presented algorithm is effective and has been adopted by CNC system of newly developed high-speed milling machine.
