Development of real-time look-ahead algorithm for NURBS interpolator with consideration of servo dynamics

In this paper, a real-time dynamics-based look-ahead (DBLA) algorithm for NURBS interpolator is proposed to generate a jerk-limited acceleration/deceleration (ACC/DEC) feedrate profile. The interpolator consists of three modules. The geometric module detects the local maximum/minimum (max/min) curvatures, and divides a NURBS curve into small segments. The dynamics module estimates contour errors at the sharp corners and adjusts the feedrates at the sharp corners. The jerk-limited module plans the feedrate profile of the curve according to the length of each segment and the given jerk limit. Simulations are performed to verify the real-time performance of the look-ahead algorithm. Finally, experiment results demonstrate that high-accuracy can be achieved with the proposed DBLA algorithm as compared to the adaptive-feedrate and the curvature-based feedrate interpolation algorithms.