Research On The Look-ahead Algorithm For High-speed And High-precision Five-axis CNC System

With the development of NC automatic programming technology, the requirement of numerical control is becoming higher and higher. Five-axis CNC machining technology is becoming a key technology in manufacturing industry, and is being widely used in aerospace, automotive ships, precision medical, military equipment and other processing areas, for its merits of high-speed and high-precision. These areas all need more complex parts and higher quality requirements. Therefor, excessive cutting process, vibration and data starvation are not allowed. Towards this end, a look-ahead algorithm for five-axis CNC system was introduced. By reading and analyzing processing data before the interpolation process, finding the danger point of trajectory and calculating the safe speed, this algorithm achieves a smoother and faster velocity at transition points. This algorithm can effectively improve the processing efficiency, as well as quality.This paper researched look-ahead technology of five-axis CNC machine tool. Established a general mathematical model which suited all five-axis machine tools; Proposed a five-axis nonlinear interpolation algorithm, which meets real-time requirements; Introduced a smooth speed control algorithm for high-speed processing; Proposed a look-ahead control strategy which is available for continuous segments in dimensional space.To analyze the kinematic characteristic of five-axis CNC machine tools, the A / C head / head five-axis machine was selected, as an example. It’s space transformation matrix and its conversion formula to the A / B head / head five-axis machine tools were developed. By this means, the theory can be applied to other five-axis CNC machine tools. This paper considered linear interpolation and circular interpolation issue separately. According to the movement of machine tool, this study analyzed the spatial interpolation process of each motion axes. For a complex special issue of S-curve acceleration / deceleration calculation method, proposed the half of S-curve acceleration / deceleration method, which simplifies the calculation process and improves the overall efficiency.Finally, based on the study of look-ahead principle, combined with five-axis CNC machine tools, a look-ahead control strategy for continue segments in dimensional space was proposed. And the simulation results verified its feasibility.