An Algorithm of Adaptive Variable Spacing for Arc Fitting Non-Circular Curve

The Numerical Control (NC) systems are only linear and circular interpolation function, and the non-circular curve must be fitted with them before processed. There are many algorithms of fitting curve with arc, but most of them have some shortcomings, such as the numbers of fitting data points and arcs segments are too many, the error controlling are difficult in arc fitting , the programming are difficult to meet the real-time NC processing requirement and so on. This paper proposed a new algorithm, which could quickly and automatically determine the best node for fitting curve with arc according to the change of curvature and the machining error. It could ensure the machining precision and efficiency. The algorithm could be directly completed programming and processing by the NCs macro program function without any other auxiliary software. The detailed algorithm process and the application programming were given.