Research On Analysis Technology Of Accuracy Retention Of CNC Machine Tool Based On Meta-action

CNC machine tools are basic manufacturing equipment in the advanced manufacturing industry,and accuracy retention is a weak link in the quality control of CNC machine tools in my country,which restricts the improvement of the comprehensive competitiveness of domestic high-end CNC machine tools.At present,the accuracy of machine tools is maintained.Systematic and comprehensive analysis and research methods have not yet been formed,and it is difficult to quantify assessment and indicators lack pertinence.This makes it difficult to improve the accuracy of CNC machine tools in a targeted manner.At the same time,it also leads to the lack of preventive maintenance strategies for users.Repairs are performed only after the failure of accuracy occurs,and the machine tool has a long downtime and high cost due to maintenance.In this context,this article relies on the support of relevant national fund projects,and takes a certain type of CNC machine tool of the THM series studied in the project as the research object,based on the meta-action theory to carry out the research on the accuracy retention analysis technology of CNC machine tools,aiming to complete the improvement Preliminary analysis of machine tool accuracy retention capability,on the one hand,finds out the variables that have a greater impact on the accuracy retention of the machine tool,so that the more sensitive influencing variables can be optimized or controlled during the design,manufacturing and operation of CNC machine tools.Measures,on the other hand,monitor and predict the accuracy indicators that have a greater impact on accuracy retention during the use of the machine tool,in order to make effective preventive maintenance measures against the accuracy degradation of the machine tool.The main research contents of this paper are as follows:First of all,according to the structural and functional characteristics of CNC machine tools,analyze the key causes of machine tool accuracy degradation from the perspective of meta-actions,and analyze the degradation process under the influence of different reasons,and maintain the accuracy of CNC machine tools in the form of time-varying accuracy reliability.Combining with the FMA structural decomposition analysis method of CNC machine tools,the related element actions that affect the accuracy of CNC machine tools are found.Secondly,in order to establish the mapping relationship between the accuracy retention of the whole machine and the accuracy retention of the meta-actions,and to find out the key influencing factors that affect the machining accuracy of the machine tool,the structural topology model of the whole machine is established according to the motion functions of each elementary movement of the CNC machine tool.It also analyzes the various error sources of the element motion and the conversion relationship between the motion error of each element motion coordinate system,and derives the deviation between the ideal tool processing point and the actual forming point of the workpiece and the machine element motion error term through the homogeneous coordinate transformation method.In this way,a comprehensive error model of the machining accuracy of CNC machine tools is established.Then,in order to find out the key influencing variables that affect the accuracy of the whole machine,a precision reliability calculation model to describe the accuracy of the accuracy retention was established by the average first-order second moment method,and the meta-action was established based on the comprehensive error model of the machining accuracy of the machine tool.The global sensitivity calculation method of each error term on the machining accuracy reliability of the machine tool in three directions in the machining space,and the partial correlation coefficient is introduced,and the influence of the interaction between the errors on the reliability of the machining accuracy is considered.According to the error data of different measurement points of the machine tool,the degree of influence of each element action error item on the reliability of machining accuracy is calculated,and the key element action error that affects the accuracy of the CNC machine tool is identified.Based on the analysis result,the corresponding accuracy maintenance can be implemented.Measures.Finally,in view of these key elementary motion error terms that affect the accuracy of machine tools,according to the characteristics of the actual degradation process of the elementary motion accuracy of CNC machine tools,and taking into account the non-linear and uncertain problems in the accuracy degradation process,based on non-linearity and uncertainty.The linear Wiener process establishes the accuracy degradation model of the element action of the CNC machine tool.The accuracy of the element action is judged to be invalid when the accuracy measurement value exceeds the failure threshold for the first time.In this way,an accuracy remaining life prediction model based on the inverse Gaussian distribution is established,which is based on the probability density function.Formally solve the remaining accuracy life of key element actions.Aiming at the problem of a single machine tool lacking relevant historical data and prior information,the particle filter algorithm is used to recursively update the posterior value of the model parameters based on the current observation data to achieve the optimization and update of the remaining life prediction results,and move through the nut The example analysis of meta-action accuracy degradation simulation experimental data verifies the accuracy and effectiveness of the accuracy degradation model and the accuracy remaining life prediction method.According to the prediction results,the preventive maintenance of machine tool accuracy can be effectively carried out.