Research On The Method Of Health Assessment Of Numerical Control Device For Machine Tool

CNC machine tools are the foundation of advanced manufacturing industry.Its manufacturing capacity and technical level are important indicators to measure the country’s economic development and overall national strength,and it is also related to the country’s strategic status.The numerical control device is the brain center of the numerical control machine tool.If it fails,it will cause incalculable production loss,especially for high-end numerical control machine tools.The maintenance methods adopted for CNC devices in China are still preventive maintenance and after-the-fact maintenance.If condition-based maintenance can be achieved,it can make up for the shortcomings of preventive maintenance and after-the-fact maintenance,obtain the best maintenance plan,reduce unnecessary machine downtime,reduce maintenance costs,and improve resource utilization.Therefore,the research on the health evaluation method of the numerical control device to solve the problem of how to evaluate the health degree according to the change of the output parameter can lay the technical method foundation for the development of a condition-based maintenance plan and reduce the impact of the shutdown due to the failure of the numerical control device.This thesis analyzes the cause of the failure of the numerical control device through a combination of theoretical analysis and experiment,determines the performance degradation characterization,and combines the improved approach to ideal solution and the fuzzy comprehensive evaluation method to realize the evaluation of the health status of the numerical control device.The specific work content as follows:In Chapter 1,the background and significance of this article are summarized,and the current research status of health status evaluation methods,health status feature extraction methods,health status evaluation standards and numerical control devices are reviewed.Finally,the main research content of each chapter is given..In Chapter 2,the failure causes of the numerical control device are analyzed,and the output voltage,ripple voltage and pulse frequency are determined as the characteristic parameters of the performance of the numerical control device.The accuracy of the characteristic parameters is verified through circuit simulation,and the corresponding monitoring plan is proposed in combination with the actual engineering.In Chapter 3,a quantitative model of health status based on the improved approach to ideal solution is proposed,which realizes the fusion of multiple characteristic parameters;combines the entropy method and the analytic hierarchy process to form a combined weighting method;uses the Mahala Nobis distance to calculate the health Index,eliminating the inconsistency of data dimension and its correlation.In Chapter 4,firstly,the criteria for grading the health status of the numerical control device were determined;secondly,five health status levels were qualitatively determined by the fuzzy comprehensive evaluation method: healthy,good,attention,abnormal and fault;then,a fuzzy membership function was established to quantify the health status levels Chemical description;Finally,through practical application,the health status of the numerical control device is evaluated.In Chapter 5,summarizes the full text and looks forward to the follow-up research work.