Research On Accelerated Degradation Test Method Of Servo Controller

The servo controller is the core unit of numerical control device control system,if the servo controller occurs a fault,the numerical control device will downtime for a fault.Compared with the manufacturing powerful country in the world,there exists a larger gap in reliability level of domestic servo controller.The middle and high servo controller is mainly relied on imports,and the self-sufficiency rate is less than 10%.Therefore,in order to enhance the competition in international markets and promote the independent innovation ability of domestic servo control,it is urgent to establish a reliability evaluation and test method for servo controller.Through evaluating the reliability of the servo controller rapidly can obtain the reliability in a short time,uncover the potential defects and weakness.Then,improving the design to achieve the goals of improving the reliability Level of domestic servo controller.In this thesis,through studying the accelerated degradation test(ADT)method of servo controller,an ADT method is proposed and lays the foundation for the rapid evaluation of the reliability for system-level product.In this thesis,the main research contents and conclusions are as follows:Chapter 1 summaries the background?purpose and significance of this research;overviews the state-of-the-art at home and abroad,and development trends of ADT and test statistical analysis method,and the existing problems of ADT for system-level product and test data statistical analysis;gives the research contents of this thesis based on the research objectives.Chapter 2 analyzes the composition and operation principle of the servo controller;determines the high temperature environment and electrical stress are the main stress factors that result in the servo controller malfunction,such as no pulse signal output?no display?filter capacitor failure and the button failure;analyzes environment stress and operation stress have the influence to the working performance of the servo controller,and the output pulse voltage variation can characterize the change of product performance,through environmental simulation test,discovers the output pulse voltage variation at different temperature stress levels can be used as the characteristic parameter to describe the performance degradation process of servo controller,and the regulation of output pulse voltage under the change of temperature stress and test time,through accelerated test;which lays the foundation for the design of the ADT for servo controller.Chapter 3 proposes a temperature stress application method which can measure the difference of output pulse voltage at different temperature stress levels during the constant stress ADT,based on the regulation of servo controller under temperature stress and test time;puts forward the selection criterion of temperature stress level,using the conditional generalized minimum covariance method and the statistical analysis of the accelerated test data;determines the accelerated stress degradation profiles,which ensures the successful implementation of ADT for servo controller.Chapter 4 carries out ADT and fits the test data using a power function as a degradation trajectory model;obtains the pseudo-failure life of the servo controller;determines the life of servo controller is lognormal distribution,utilizing graph analysis method,goodness-of-fit test and correlation test method;on this basis,calculates the reliable life of the servo controller under operation temperature stress based on Arrenius model;the test result shows that the reliability of the servo controller can be quickly evaluated,using the ADT method proposed in this thesis.Chapter 5 summaries the research contents of this thesis and prospects the further research work.