Design and implementation of integrated non-uniform rational B-spline and digital differential analyser interpolators for computerized numerical control servocontrollers

Abstract

The purpose of this article is to propose the design and implement an efficient and open real-time non-uniform rational B-spline (NURBS) interpolator for computerized numerical control (CNC) motion control. The proposed architecture of real-time NURBS interpolator integrates the advantages of digital differential analyser (DDA) and the native NURBS interpolator with the help of the data conversion module. First, the desired compensation positions are generated by NURBS interpolator concerning feedrate and curvature for manufacturing accuracy. A data conversion module is then applied to transform the position commands from float to integer. Using this integral-type position command, the pulse trains can be generated by DDA for the AC servomechanism in position mode. The simulation and experimental results validate that this novel real-time NURBS controller is effective and efficient enough to drive the general servomechanism without changing the control scheme of the traditional AC servomotor.