Research on adaptive non-uniform rational B-spline real-time interpolation technology based on acceleration constraints

Abstract

In order to solve the problems of low machining precision and efficiency in machining complicated parametric curves in traditional computer numeric control systems, non-uniform rational B-spline (NURBS) real-time interpolation was studied. Considering the problem of feed speed fluctuation in a traditional NURBS interpolation method, the adaptive correction interpolation algorithm that is proposed corrects the calculational accuracy of the next interpolation point parameter value, and the correction time is mutated adaptively according to the length of the interpolation precision and interpolation cycle. This approach is based on the premise that the interpolation cycle will improve the correction accuracy as much as possible, thereby minimizing the interpolation feed speed fluctuation. To mitigate the problem of a large number of calculations and high calculational complexity in feed speed planning of NURBS real-time interpolation, we use a velocity planning algorithm based on a feed speed pretreatment curve; thus, the interpolation feed velocity planning tasks are completed on a non-real-time cycle, the maximum acceleration and jerk requirements of the machine tool are fully considered, and each interpolation point is planned during the speed planning period, which avoids the use of a complex planning algorithm and obtains a smoother velocity curve. Finally, the correctness and effectiveness of the proposed approach were verified by simulation.