Analysis And Evaluation On Dynamics Behavior Of Interpolation Algorithm In High Speed Machining

The rapid development of high speed machining has brought out new commands to interpolation technology. The interpolation algorithm based on geometry characteristics can no longer match the need of high speed machining, because it does not consider the static and the dynamic characteristics of the machine tool in high speed condition. In this dissertation, the dynamics behaviors in interpolation algorithm of high speed machining are deeply analyzed, and those influence the interpolation are evaluated. A novel interpolation algorithm suitable for high speed machining is proposed based on the work. The main contents of this dissertation are: This research work focuses on the relationship between the geometry characteristics of the machined part and the interpolation process. The connections between the curvature of the curve, the interpolation precision, and the acceleration in interpolation are deeply studied. It is discovered that the interpolation error can be greatly decreased by considering the curvature of the curve in interpolation algorithm. The dynamic models of the feed systems in CNC system are built. The relationships between the dynamic parameters and the interpolation results are concerned. The parameters which have great influences in the interpolation are determined and the dynamic verification inequalities for planning federate and acceleration/deceleration are defined. The example demonstrates that the federate change rule in the new curve interpolation algorithm matches the performance of the machine tool better after considering the dynamic characteristics of the machine tool. The function of look-ahead technique in interpolation is discussed. Compared with the linear interpolation, the look-ahead technology is modified to adapt the curve interpolation. Integrating all the analyses in this dissertation, the look-ahead curve interpolation algorithm based on the geometry characteristics and the dynamic characteristics of the machine tool is finally proposed. Moreover, the evaluating software for the interpolation algorithms is developed. Through the human-machine interface, user can choose the interpolation algorithm, set the interpolation control parameters, and set the dynamic parameters of the machine tool. The evaluating software is able to simulate the working of the interpolator in CNC system. The software can also analyze the performances of different interpolation algorithms in diverse machine tools and under diverse machining conditions.