| After a long period of exploration and practice,statistical process control is widely used in the monitoring of quality characteristics and statistical adjustment of the process.As one of the important tools of statistical process control,control chart can timely warn the change of quality characteristics through online monitoring of the process to reduce losses.The continuous improvement of production and consumption level puts forward higher requirements on the ability of enterprises to monitor the quality of multiple products at the same time.When monitoring multiple products simultaneously,few studies take the different field environments of products into consideration.Traditional control charts usually assume that the failure rate of each product follows the same parameters.However,in real life,different field environments make such assumption invalid.In order to solve the above problems,this paper proposed a new control chart based on likelihood ratio statistic.This statistic takes account of the variability of the product failure rate caused by the difference in the field environment,which can be used for overall reliability monitoring.Simulation results show that the proposed control chart has good detection capability under different sample sizes and environmental differences.At the same time,the differences between products in the field environment get smaller,the detection ability of the control chart get stronger.This paper also gives a detailed explanation from the aspect of SNR.In the end,this paper introduces the application process of control chart based on the maintenance data of elevator company.The results show that the control chart proposed in this paper has good application in practice.At the same time,from the actual data,we also verified the impact of product field environment differences on product failure.Compared with the traditional method that assumes the same distribution of multi-data flow parameters,the method proposed in this paper is more practical. |
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