Development Of Interpolation Instruction Of Parametric Spline In Open Architecture Cnc

CNC technology is the foundation and core of the modern advanced manufacturing technology, at present, the manufacturing industry in every country is trying to enter a new era through developing CNC technology, it is essential to develop advanced manufacturing technology with CNC technology being the core and this has become an important way to accelerate economic development and enhance the comprehensive national power. Compared with a series of defects of traditional CNC technology, open architecture CNC system has become the main trend of CNC technology with its advantage of being modular, reconfigurable and scalable.As the core of CNC technology, interpolation technology plays a decisive role in the performance of CNC system. Nowadays, with the continuous development of science and technology and the growing demand of people's needs, products with sophisticated curved surface shape are becoming more and more essential, at the same time, there is a increasing demand towards their contour accuracy. Because the traditional linear and circular interpolations are clearly no longer able to meet the processing requirements, people start to seek and explore other new interpolation techniques. The NURBS curve in parametric spline curves integrates the powerful function of Bezier and B splines, it has been the hot spot of research because it can express quadratic curves and surfaces except for parabola accurately. In this dissertation, the nature and characteristics of NURBS curve and the influence of weight towards curve were analyzed. The positive and negative calculation algorithm of NURBS curve was studied. In real-time interpolation algorithm, based on Taylor expansion method, Runge-Kutta method with higher accuracy was proposed, and the correctness of the method was verified through simulation. At the same time, the restriction on the chord error brought from the adaptive speed adjustment in curve interpolation was analyzed.The simulation system corresponding to the above algorithms was developed on the platform of VC++, and the rationality and correctness of algorithms was verified combined with MATLAB software. Finally, the instruction format of the NURBS interpolation function was defined and the NC codes was generated. Open architecture five-axis CNC machine tools worked as experimental platform, a typical curved surface was selected and the effectiveness and correctness of the algorithm was verified through the processing experiments of surface interpolation.