Research And Implement Of High Performance Hardware NURBS Curve Interpolation Algorithm Based On FPGA

CNC technology is a sign of manufacturing industry development level, interpolation technology as the key technology of numerical control technology, decides the machining efficiency and machining precision of parts. Traditional interpolation technology uses tiny straight line instead of free curve, the disadvantage is low efficiency and poor accuracy, but the NURBS interpolation technology can improve this defect, therefore, the research of the NURBS interpolation technology is of great significance for the development of numerical control technology.Based on the research on the basis of NURBS curve and its property, the NURBS curve points and the evaluation method of vector has been introduced. Preprocessing matrix expression of NURBS is used to curve, computing the correlation coefficient for the call of real-time interpolation. On the analysis of the contrast Adams differential method, Newton iteration method and Taylor expansion method, choose the Taylor expansion method for the study of the parameter evaluation method of interpolation. According to the sharp corner, the NURBS curve is piecewise processing. The adaptive adjustment of speed in the process of NURBS interpolation is realized by using local arc approximation method, it meets the requirements of the machining accuracy and improves the quality of the processing. In terms of speed control, the S type of acceleration and deceleration control method was adopted, in order to solve the problem of the deceleration point is not predict, this paper proposes a cascade filter based S deceleration control method, the method adopts the cascade filter to filter feed speed, to get a smooth transition speed and avoid the impact of the machining process.In the experimental simulation, interpolation algorithm was modular, and it was realized in the programming model of VS2005, MATLAB was used to process the data, and the feasibility of the interpolation algorithm was verified.In the hardware platform of NURBS interpolation algorithm implementation, the architecture of the interpolation system are analyzed, based on the development process of SOPC, the soft core processor of NURBS interpolation algorithm was customized, and the software code was ported to the Nios II software environment. Finally, the example shows the superiority of NURBS interpolation algorithm.