Behnam Moetakef Imani - Associate Professor, Ferdowsi University of Mashhad
Amirmohammad Ghandehariun - M.Sc. Student, Ferdowsi University of Mashhad;

Various Methods for parametric interpolation for NURBS curves have been proposed in the past. However, the errors caused by the approximate nature of the NURBS interpolator were rarely taken into account. This paper proposes an integrated look-ahead algorithm for parametric interpolation along NURBS curves. The algorithm interpolates the sharp corners on the curve with the exact Pythagorean-hodograph (PH) interpolation. This will minimize the geometric and interpolator approximation errors simultaneously. The algorithm consists of three different modules: a sharp corner detection module, a jerk-limited module, and a dynamics module. Simulations are performed to show correctness of the proposed algorithm. It is shown that the developed method improves tracking and contour accuracies significantly compared to previously proposed adaptive-feedrate and curvature-feedrate algorithms.

Numerical control, high speed machining,PH curve