The performance of variable sampling interval EWMA control chart with measurement errors

The effect of measurement errors on the performance of the most adaptive Shewhart control charts is investigated. In this paper, the effect of measurement errors on the performance of the Variable Sampling Interval (VSI) EWMA control chart is investigated. For this aim, the covariate errors model and Markov chain method are used to compute the evaluation indices. Furthermore, the effect of taking multiple measurements on the performance of the VSI EWMA is evaluated. Also, the performance of the VSI EWMA and FSI EWMA control charts in presence of measurement errors is compared in terms of Average Time to Signal (ATS). At the end, an example is provided to show the application of the proposed VSI EWMA control chart in reducing the effect of measurement errors.

Keywords:

Adaptive control chart , Exponentially Weighted Moving Average (EWMA) , Markov chain method Measurement errors , Variable sampling interval (VSI).