多台数控机床最小维修的可靠性评估

Reliability assessment of multiple NC machine tools with minimal repair

摘要:

为了解决数控(NC)机床最小维修的可靠性评估问题,提出了基于随机点过程的多台NC机床时间截尾的可靠性评估的可修系统方法,建立了故障时间的非齐次泊松过程(NHPP)模型.用Fisher信息矩阵(FIM)法给出了模型参数的点估计和区间估计,同时也给出了NC机床的累积平均无故障间隔时间(MTBF)和累积故障强度在截尾时间的点估计和区间估计.AIC信息准则计算结果表明,对于故障时间具有某种单调趋势的NC机床最小维修可靠性评估,可修系统方法优于统计分布方法.模型通过了趋势检验、更新过程检验和拟合优度检验.

Abstract:

A repairable system approach of reliability assessment for multi-NC machine tools with time truncation based on stochastic point process is proposed,and a non-homogeneous Poisson process(NHPP) model for failure time is built.The point and confidence interval(CI) estimators of model parameters and reliability indices,such as accumulated mean-time-between-failure(MTBF) and failure intensity at truncated time,are all given by Fisher Information Matrix(FIM) method.The values of Akaike information criterion(AIC) show that repairable system approach has advantage over statistical distribution method when failure times of NC machine tools with minimal repair have monotonic trend in reliability analysis.The proposed model is passed by trend testing,renewal process testing and goodness-fit-test respectively.