基于双NURBS的角度平滑插补算法研究与实现
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摘要
针对五轴数控微小线性段加工,因驱动器速度变化,导致速度转换点处加速度和加加速度不连续,致使工件表面加工存在不连续的问题,提出一种基于双NURBS的角度平滑插补算法。通过样条曲线拟合,计算出最佳控制点,提高刀具中心点轨迹拟合精度,达到表面加工光滑。仿真结果表明:采用该算法能够改善刀具运动的平滑度,提高模具和工件在五轴加工中的精度。
For the processing of tiny linear segments in five-axis CNC, the acceleration and jerk at the speed transition point are discontinuous due to the change of the drive speed, resulting in a matte surface. A double-NURBS based tool vector interpolation algorithm is proposed. Through the spline curve fitting, the optimal control point is calculated, and the continuity of acceleration and jerk at the transformation point of the tool center point is improved, and the surface processing is smooth. The simulation shows that the algorithm can improve the smoothness of tool motion and improve the accuracy of mold and aerospace parts in five-axis machining.
For the processing of tiny linear segments in five-axis CNC, the acceleration and jerk at the speed transition point are discontinuous due to the change of the drive speed, resulting in a matte surface. A double-NURBS based tool vector interpolation algorithm is proposed. Through the spline curve fitting, the optimal control point is calculated, and the continuity of acceleration and jerk at the transformation point of the tool center point is improved, and the surface processing is smooth. The simulation shows that the algorithm can improve the smoothness of tool motion and improve the accuracy of mold and aerospace parts in five-axis machining.
引文
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[2]Li H Y,Chen L J. Study on five-axis NURBS path generation method and direct-interpolation for CNC system[J]. Applied Mechanics and Materials,2014,621:162–166.
[3]Yang J X,Altintas Y. Generalized kinematics of five-axisserial machines with non-singular tool path generation[J]. International Journal of Machine Tools and Manufacture,2013,75:119–132.
[4]吴闯,吴继春,杨世平,等.基于NURBS曲线的S型级数式速度规划算法[J].计算机集成制造系统,2015,21(12):3249–3255.
[5]Wu Y,Wang Y,Bi Q Z. Optimazition and selection of rotations of five-axis machining[J]. Modular Machine Tool&Automatic Manufacturing Technique,2009(5):1–5.
[6]刘建伟,王卫英,曾礼平.高速数控加工复杂曲线的刀具轨迹计算方法[J].轻工机械,2012,30(2):79–81.
[7]符祥,尹红,黄勇,等.基于相关点与几何约束的直线匹配方法[J].南昌航空大学学报:自然科学版,2018,32(1):41–47.
[8]Yuen A,Zhang K,Altintas Y. Smooth trajectory generation for five-axis machine tools[J]. International Journal of Machine Tools&Manufacture,2013,71(8):11–19.
[9]董海涛,潘海鸿,黄丽宇,等.一种优化的NURBS曲线插补算法[J].计算机集成制造系统,2014,20(9):2172–2177.
[10]张君,张立强,张守军,等.面向五轴加工的等距双NURBS刀具路径同步插补方法[J].计算机集成制造系统,2015,21(6):1523–1528.
[11]Wu J,Zhou H,Tang X,et al. Implementation of CL points preprocessing methodology with NURBS curve fitting technique for highspeed machining[J]. Computers&Industrial Engineering,2015,81:58–64.
[12]周凯红,唐进元.非球头刀单触点宽行加工刀具运动优化方法[J].计算机辅助设计与图形学学报,2018,30(10):1966–1978.