Research Of NURBS Interpolation Algorithm And Acceleration-deceleration Control For Five-axis Machining

As a typical representative of high-grade NC machine tools,five-axis NC machine tool embodies the development level of manufacturing industry of one nation.The widely used NURBS curve interpolation algorithm in the field of high-speed and high-precision interpolation has become the key to improve the performance and market competitiveness of five-axis NC machine tool.The interpolation algorithm and acceleration-deceleration control algorithm of NURBS curve in five-axis tool point trajectory planning are researched in this thesis.A new NURBS interpolation algorithm based on Gear linear parameter prediction method and proportional correction method is proposed.The simulation on PC indicates the high-speed,high-precision and little fluctuation of this method.A sectional velocity planning by speed sensitive point search is proposed in this thesis.The look-ahead method combines the the S-shape model and trigonometric model with adaptive acceleration-deceleration control,which meets the flexible requirement of machine tool and is calculated simply.The kinematics analysis of five-axis NC machine is carried out,and the mapping relations between the tool point coordinate,axis vector and the motion of the machine tool axis are obtained.The Linux software system platform is built on the NUC950 core hardware system,including the device drivers of matrix keyboard and LCD.Meanwhile,the software modules such as decoding module and user graphical display interface are developed.A five-axis NURBS interpolation instruction format is designed and the tool axis vector control strategy in five-axis tool path planning is introduced.Finally,the simulation and processing results demonstrate the effectiveness and correctness of the interpolation algorithm.