| Numerical control technology is very important to the manufacturing industry,especially multi-axis numerical control technology,which reflects the level of acountry’s manufacturing industry.In today’s numerical control processing field,the processing of continuous micro-line segments is becoming more and more popular.At this time,if the traditional speed planning method is adopted,it will greatly limit the increase in processing speed.Therefore,the look-ahead processing of the processing trajectory can not only greatly increase the processing speed,but also prevent the machine tool from slowing down at the sharp inflection point and causing shocks.In view of the complex problem of the complete S-curve acceleration and deceleration calculation process,the complete S-curve acceleration and deceleration is simplified to improve the calculation efficiency;the fixed segmentation method commonly used in the current CNC system is improved,and the processing path is connected according to the point.Set the speed sensitive points according to the speed change rate and the included angle,and divide the look-ahead interval according to the speed sensitive points,so as to realize the adaptive segmentation according to the processing trajectory characteristics,and avoid the machine tool from decelerating sharply in smooth places.A three-axis look-ahead algorithm for adaptive continuous micro-line segments is proposed.It adopts the idea of pushing and backtracking.First,starting from the starting point of the interval trajectory,along the processing direction,according to the length of the trajectory of the previous segment and the corner size constraints at the junction point,the available data at each junction is calculated.The optimal processing speed reached,when planning to the end of the interval,adjust the processing speed at each connection point according to the back-end trajectory length constraint along the opposite direction of the processing,and finally calculate the end point of the lookahead interval according to the corner size and the back-end trajectory length constraint Optimal transition speed.Based on the three-axis look-ahead planning strategy,an adaptive five-axis lookahead algorithm for continuous micro-line segments is proposed.First,the structure of the five-axis CNC machine tool and the translation and rotation transformation in the space of the five-axis CNC machine tool are studied in detail,the causes of nonlinear errors are analyzed,the implementation process of RTCP is studied,and then a preprocessing method is proposed.The NC code is preprocessed to calculate the change trajectory of the tool axis point,and look-ahead speed planning is carried out based on the tool axis trajectory to avoid sudden changes in the speed during interpolation caused by the nonlinear error introduced by the rotary axis.Finally,an experimental platform was built,and simulated numerical control processing software was written based on the Windows system using VC++,and verified under laboratory conditions.The results show that the adaptive continuous micro-line segment three-axis look-ahead algorithm proposed in this paper improves the processing compared with the traditional planning algorithm.Efficiency,its speed changes smoothly;the five-axis look-ahead planning strategy adopting the preprocessing method can effectively avoid sudden changes in speed during interpolation and ensure the smoothness of machine tool processing. |
