Bayes and fault tree based reliability evaluation method of numerical control machine tool

Abstract

A Bayes and fault tree based reliability evaluation method of a numerical control machine tool belongs to the technical field of reliability evaluation method of the numerical control machine tool. The numerical control machine tool is seen as a system composed of subsystems, and fault data of the subsystem in the same factory batch serves as prior information; a joint probability density functionof failure rates of failure subsystems serves as an onsite data likelihood function, logarithm reverse gamma distribution serves as conjugate prior distribution of the reliability, and a joint priordistribution probability density function of scale and shape parameters of weibull distribution obeyed by fault data is determined; the mean reliability value of the subsystems in a given task time isobtained by using a Bayesian theory; and a fault tree model is established according to connection among the subsystems and influence of the subsystems on a machine tool system, and a fault tree theory is used to calculated the reliability of the numerical control machine tool. The sample amount of prior information can be increased, complex sample compatibility test is avoided, and the compatibility of the prior information is ensured.

Description

technical field [0001] The invention belongs to the technical field of reliability evaluation of numerical control machine tools, in particular to a reliability evaluation method of numerical control machine tools based on Bayesian and fault tree. Background technique [0002] Reliability is an important indicator of the performance of CNC machine tools, so reliability evaluation is an important content of the performance evaluation of CNC machine tools. High-quality CNC machine tools have the characteristics of few fault samples, so the evaluation of small sample data is the focus of current research on the reliability of high-quality CNC machine tools. [0003] Since there is no unified standard for the reliability evaluation method of CNC machine tools for small sample fault data in China, and the evaluation of small sample data is difficult, it is very important to find a reasonable and effective small sample data reliability evaluation theory. [0004] As an important ...

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Problems solved by technology

Therefore, it is of practical engineering significance to study a method to solve the problem of difficult evaluation of high-reliability CNC machine tools.

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