Research & Implementation Of Real-time NURBS Interpolation Algorithm For Embedded CNC Systems

As one of the key and supporting technology of modern equipment manufacturing automation, numerical control technique promotes the innovation and upgrade of traditional manufacturing industry. Embedded NC systems are getting more and more widely used due to its advantage of real-time ability, adaption and reliability. With the rapid development of high-speed and high-precision NC systems, the NURBS interpolation technology is a key to improve the performance of NC system and market competitiveness.A quick solution of NURBS interpolation is researched in this thesis, which puts forward a linear parameter prediction based on Hamming method and an step-length error compensation based on Steffensen iteration method. The simulation on PC indicates the high-speed, high-precision and little fluctuation of this method. A sectional velocity planning by curvature acceleration and deceleration is proposed in this thesis. The look-ahead method combines the cubic polynomial model and the S-shape model with adaptive ACC/DEC control, which meets the flexible requirement of machine tool and calculated simply.The real-time Linux NC system platform is built on the NUC950 core hardware system including the device drivers of matrix keyboard and LCD. The standard Linux kernel's real-time reconstruction is made by RT-Preempt patch in the field of task scheduling and interrupt responses. Meanwhile, The decoding, the fine interpolation process and QT graphical interfaces are implemented integratedly. Finally, the simulation results demonstrates the effectiveness and application value of the interpolation algorithm.