Contour Error Modeling And Immunity Analysis Of CNC Machine Tools

The CNC machine tool is the "working machine" of the manufacturing industry and the machine that makes the machine.The contour error of the multi-axis synthesis of CNC machine tools is the core index that determines its machining accuracy.It is the result of the coupling effect of the position error of the feed system.It depends on the dynamic characteristics of the feed system and manufacturing assembly,and will be affected by external interference factors such as electromagnetic disturbance.Influence.Therefore,this thesis takes the contour error of CNC machine tools as the research object,establishes the dynamic model of the machine tool feed system,studies the modeling and solution methods of single-axis position error and multi-axis coupled contour error,and analyzes the influence of electromagnetic disturbance on machine tool control.The influence of the error,a test scheme is proposed,and the specific research contents are as follows:Firstly,considering the dynamic error of the machine tool feed system and the geometric error in the static error,a contour error modeling method for electromechanical coupling system is proposed,which is used to predict the contour error in actual machining.Aiming at the servo drive system,according to the vector control strategy,the three-loop control model of the motor is established,and the transfer function of the whole system is obtained by using the Mersenne gain formula,and the parameters are identified.For the mechanical transmission system,the structure of the mechanical transmission is analyzed,the dynamic model of the mechanical transmission system is established according to the connection stiffness of each unit,and the parameters are identified.Aiming at the inherent geometric error of the machine tool,the linear regression method is used to establish the polynomial model of the single-term error,and the homogeneous coordinate transformation method is used to establish the spatial comprehensive geometric error model.Then,based on the servo drive system model,the mechanical transmission system model and the geometric error model,the position error model of the machine tool feed system is established,and the accuracy of the model is experimentally verified by comparing the Simulink simulation results and the actual test results.Based on the single-axis position error model,combined with the spatial comprehensive geometric error model,a multi-axis coupled contour error model is established,and the linear interpolation and circular interpolation contours are experimentally verified.The results show that the model can more accurately predict the actual machining.contour error.On this basis,the visual analysis software of machine tool contour error is developed to provide reference for the prediction and compensation of contour error in actual machine tool processing.Finally,according to the influence of electromagnetic disturbance on the contour control error of the machine tool,a quantitative test method for the immunity of the numerical control system is proposed.By applying electromagnetic disturbance to the electrical part of the CNC machine tool,collecting and analyzing the change of the position data of the machine tool feed system before and after the disturbance is applied,the influence of electromagnetic disturbance on the machining accuracy of the machine tool is determined,and the electrostatic immunity is taken as an example to counteract the disturbance of the CNC system.The degree of testing has been carried out to verify the effectiveness of the method,thus providing a basis for the testing and evaluation of the anti-interference ability of the numerical control system.