Feedrate Scheduling of NURBS Interpolation Based on a Novel Jerk-Continuous ACC/DEC Algorithm

In order to improve the motion smoothness while maintaining the machining efficiency of the non-uniform rational B-spline (NURBS) interpolation, a novel jerk-continuous acceleration/deceleration (ACC/DEC) algorithm and the corresponding feedrate scheduling method are proposed in this paper. The polynomial and trigonometric functions are combined to construct the jerk-continuous ACC/DEC profile. Meanwhile, to reduce the computational load of feedrate scheduling, a proportional control method is proposed to determine the form of the jerk profile, which also improves the flexibility of feedrate control. Therefore, the maximum jerk and acceleration can be maintained to achieve higher machining efficiency compared with the conventional trigonometric methods, while the feedrate scheduling process is far simpler than the polynomial methods with continuous jerk. In addition, to improve the machining accuracy and motion smoothness, the round-off error caused by cycle sampling is also considered in feedrate scheduling and real-time interpolation. The proposed ACC/DEC algorithm is simplified to achieve the round-off error compensation, which can guarantee the continuity of jerk profile. A series of simulations and experiments for two NURBS curves is conducted to verify the good performance and applicability of the proposed method.