Development Of Function Of Tabulated Curve Interpolation In Open Cnc System

Because traditional CNC system lacks universal and standard interface, that is difficult to add new programs and to expand the new control strategy function. NC system transfers from closed system to open modular system, which is the current of the devlopment of NC. So the research of the open CNC system is great significance.Interpolation is an important part of CNC system, and particularly, the high-grade interpolation commands, such as A, C, NURBS interpolation command, can achieve high-speed and precision process for complex spline curves and surfaces. Some foreign high-grade CNC systems already have such a high-grade interpolation commands, China has already done some research in this field. The tabulated curve interpolation algorithm has been researched in this article. The function of interpolation has been developed based on the existing open NC system and the program.The tabulated curve interpolation function has been development based on the internal structure and program of the existing open NC system in the Lab. The curve generation algorithm and characteristics for tabulated curve (Akima,Cubic) are studied, then a feasible interpolation algorithm is presented. Sometimes, because the coordinates of the measured data points is not accurate enough, the generated curve or surface is often not smooth enough applying these "bad points". So it needs to deal with smoothness. The tabulated curve smoothness will be researched based on the existing curve smoothness. And the smoothing preprocessing module is developed. The NC code is dealed with smoothness in advance, then the smooth NC code is outputted.The correctness of the algorithm is verified with a simulation platform which is developed by vc++. The program will be added to an open CNC system. And then the interpolation function of the tabulated curve is achieved. At last, a typical surface is selected to complete the processing experiments. The practical feasibility of the interpolation command and the correctness of the interpolation algorithm are verified.