Circular interpolators for numerical control. A comparison of the modified DDA techniques and an LSI interpolator

Abstract

In numerical control of machine tools, the control of the tool path to follow a specific curve is accomplished by interpolation. A well-known interpolation technique is based on the functional operation of the digital differential analyzer (DDA) integrator. This method of NC path control can be implemented on-line using digital hardware or software. This paper discusses modifications of the DDA interpolation technique for improved accuracy and computation speed, whilst retaining the suitability of the technique for integer computation or implementation using digital hardware. Results obtained from the best modified DDA technique are compared with those obtained from a widely-reported LSI hardware interpolator.