Modeling and analysis of the linear axis feed system in CNC machine tools

Abstract To achieve a more accurate analysis of the positioning accuracy of the feed system in CNC machine tools, this study employs the lumped parameter method combined with the Lagrange equation to establish an electromechanical coupling dynamic model of the linear axis feed system. This model allows parameter correction of intermediate components within the system, significantly enhancing the model’s accuracy. To validate the model’s accuracy, a simulation analysis and comparative experiment were conducted using a laboratory-constructed linear axis workbench as an example. The results demonstrated that the analysis outcomes of the parameter-corrected model were more consistent with the experimental results. Subsequently, simulation analyses based on the model were performed to explore the effects of different factors on workbench displacement. The findings revealed that the torsional stiffness of the motor shaft has a substantial impact on workbench displacement, while the axial stiffness of the screw shaft has a minimal effect. The position loop gain does not affect workbench displacement. This study provides theoretical support for further in-depth analysis of the dynamic characteristics of machine tool feed systems and for suppressing dynamic errors.