EWMA p控制图的设计

Design of EWMA P Control Chart

针对生产过程中出现异常数据的问题,在Shewhartp控制图和EWMA控制图的基础上,设计了监控次品率P的EWMA p控制图,给出该控制图的统计量定义、平均链长定义.分别使用马尔科夫链和积分方程方法计算新控制图的平均链长,并比较EWMA p控制图与EWMA控制图的监控效果,结果显示EWMA p控制图和EWMA控制图监控效果相似.由于EWMA p控制图直接显示的是次品率,更直观反映生产产品质量,并且非常适合监控控制情况不完善的生产过程,可以在实践中应用.

Aiming at the problem of abnormal data in the production process,based on the Shewhart p control chart and EWMA control chart,this paper designs a control chart to monitor the defective rate,and gives the definition of statistics and average chain length of the control chart.Markov chain method and integral equation method are used to calculate the ARL of the new control chart,and the monitoring effect of the control chart and EWMA control chart is compared.The results show that the monitoring effect of the new control chart and EWMA control chart is similar.Because the new control chart directly shows the defective rate p,it can more directly reflect the quality of production products,and it is very suitable for monitoring the imperfect control of the production process,so it can be applied in practice.