Research on Adaptive NURBS Interpolation Algorithm for 3D Engraving of Manipulators

Abstract

In the process of engraving three-dimensional (3D) complex shape using manipulators, there are many inflection points and many start-stop operation, which cause shock easily. To resolve these problems, an adaptive NURBS curve interpolation algorithm combined symmetrical sine function acceleration/deceleration (ACC/DEC) control (S-A-NURBS) is designed. 3D information is adaptively interpolated by adjusting knot vector of NURBS curve ensuring smooth transition of complex contours. And in order to modify feed rate and interpolation step size of the machining, the ACC/DEC strategy considered symmetrical sine function is discussed ensuring motion smoothness and accuracy, reducing manipulator's shock and chord error at the same time. At last, to evaluate the proposed approach, the simulation verification on the model of KUKA manipulator KR240-R2900 in SimMechanics environment is conducted to follow a 3D NURBS curve. Numerical simulations demonstrate the effectiveness of the proposed scheme.