Multi-body System-oriented Kinematics Modeling And Geometric Error Analysis For Five-axis NC Machine Tools

Post-processing of CNC machine tools is the important component of the CAD/CAM technology and NC programming system.Also,it is important way of compensating geometric error by software.The kinematics modeling is important to post process of CNC machine tools.In this process,cutter location data gived by cls file is coverted into NC data based on motion struction and relationship among each axis.Recently no error processing method is generally used.But the geometric error should be compensated in an ideal post-processing system.The kinematics modeling geometric error compensation and error parameters identification of 5-axis CNC machine tools are mainly researched in this thesis. And finally,this system is verified.The three key contents are researched as following:(1)The kinematics modeling for 5-axis CNC machine toolsThe structure of one special five-axis CNC machine tools is researched.There is a certain angle between tool rotation axis and axis of Z.The method of Kinematics modeling based on multi-body system is explored.And kinematics modeling of CNC machine tools is established.In this model the angle of two axes could be arbitrary set.Then cutter location data is converted into NC data based on the kinematics model.(2)Geometric error compensationThe motion structure of current popular 5-axis CNC machine tools is introduced.According to the configuration of the two axes,motion forms of 5-axis CNC machine tools classfied into three types.According to multi-body theory topology structure and arrays of low-order body of each kind are identical.Based on 5-axis CNC machine tools of table-tilting,geometric error thesis based on multi-body system is perfected.The NC instruction after geometric error compensation is solved by iteration method.And NC instruction under ideal status is used as initial values.(3)Error parameter identificationThe error parameter identification of translational axis and rotation axis are researched.And based on that,error parameters can get.Then NC instruction after error compensation is caculated.(4)System verificationPost-processing system for five-axis NC machine tools is developed in Visual C++6.0.And NC data of no error verificated in VERICUT.The NC instruction and simulation model of pre and post error compensation are compared. The structure of 5-axis CNC machine tools and the theory of multi-body system are researched.The method of kinematics modeling based multi-body system is explored.The error theory of multi-body system is perfected,and then it can be used in all kinds of five-axis CNC machine tools.