自动调节进给速度的NURBS插补算法的研究与实现

Research and implementation of NURBS interpolation algorithm for adaptive feed speed

现代计算机数控系统中已经普遍使用非均匀有理B样条插补,但大多数非均匀有理B样条插补算法都致力于取得恒定的进给速度而不是轮廓精度。对此,提出了一种限定弓高误差的自动调节进给速度的空间非均匀有理B样条曲线插补算法,它在通常加工时,是泰勒展开式2阶近似插补,而在小曲率半径零件的高速加工时,可以根据曲率半径和限定的弓高误差自动地调整进给速度,保证了轮廓加工精度。加工实例证实了这种插补算法的实时性和实际应用的可行性。

Non-uniform rational B-spline （NURBS） interpolation algorithms have been provided in modern Computer Numerical Control （CNC） systems,however most of them focus on a constant feed speed without considering the contour accuracy. In order to deal with this problem, an adaptive feed speed interpolation algorithm for 3D NURBS parametric curves with confined chord errors was proposed. When the instantaneous radius of curvature was small enough, the proposed interpolation algorithm would automatically reduce the feed speed to meet the radius of curvature and restrictive specified chord error, while in the other circumstances it used the second-order Taylor＇s expansions approximation interpolation algorithm to obtain constant feed speed so that the contour accuracy in the CNC system was guaranteed Experimental results were provided to verify the feasibility and precision of the proposed interpolation algorithm.