Research On An Interpolation Algorithm For High-speed Carving Machines

CNC system is the control core of carving machine, in which capabilities of trajectory interpolation and velocity control are directly related to the performance of carving machine and will make influence straightly on the manufacturing quality and efficiency, especially for high-speed machine.According to the requirements and characteristics of low-cost CNC system for high-speed carving machine, smooth velocity control of line and arc interpolation, NURBS interpolation algorithm and cutter compensation have been studied. The main contents and contributions are as follows:(1) Line and arc interpolation with bell shape feedrate profile is studied. it is found that the pulsed output results in feedrate fluctuation with time dividing method, and the binding algorithm of displacement, feedrate and time is proposed to improve the machining stability effectively.(2) Aiming at continuous machining of plentiful micro-line in complex surface NC program, arc transition algorithm is proposed to improve machining precision and efficiency. It is an effective method for continuous machining of micro-line.(3) Considering the actual machining capacity of machine tools, local and global feature of motion trajectory in machining process, a simple adaptive interpolation algorithm for NURBS curve is presented to achieve adaptive transformation of feedrate, which makes curve machining smoother and more effective.(4) C type cutter compensation with arc transition is adopted to effectively improve machining stability based on analysis of existing cutter compensation algorithms.All proposed algorithms are realized on CNC platform based on DSP system developed by ourselves, and have been proved to be effective by simulations and experiments. these algorithms are valuable for high-speed and high precision motion control such as CNC machine and robot.