High-speed Consecutive Small Line Blocks Interpolation Algorithm Based On Machining Dynamics

With the development of high speed machining technology, the high-speed trend of NC machine tools is increasingly prominent. Micro linear segments are generated by CAM system in surface machining to approach the complex curve. This leads to a large number small line blocks in high speed and high precision machining. So feed-rate scheme and how to determine the constrain conditions of the corner's feed-rate become the key points to ensure the efficiency and precision of machining. In addition, the dynamics characteristic of machine tools has more impact in high speed machining environment. If only the work pieces geometry is considered and machining dynamics characteristic is ignored, the parts precision can't be satisfied. Small line blocks interpolation algorithm based on the analysis of machining character is proposed, which considered the dynamics characteristic of machine tools. The main contents of this thesis are:The problems in small line blocks interpolation in high speed machining were analyzed. The trace back method of look ahead control is proposed and compared with the trace forward method. For avoiding the gentle impact, the detail implementation of S-type acceleration algorithm in small line blocks interpolation is described.The constrain conditions of corner's feed-rate considered with dynamics characteristics are built, including machine's accelerating and decelerating capability, the error of corner machining, the max acceleration of the machine, and the machine dynamical behavior.Performance evaluation system of interpolation algorithm is built. Two level appraise targets include profile control performance and machining performance. The evaluating software for the interpolation algorithms is introduced. The simulation test platform is developed. Evaluating software and simulation test platform can analyze the interpolation algorithm result under the different environment and conditions.The influences of constrain conditions to interpolation algorithm are discussed and the characters of interpolation in different conditions are compared. They can guide the development of interpolation algorithm and design of machine tools.