摘要：HotellingT2control chart not only reflects the correla-tions between different quality characteristics but also has good efficiency on monitoring multivariate quality characteristics in production process. A new alternative control chart was constructed after the original products data are processed by using multivariate exponentially weighted moving average for cumulating failure effects becauseT2control chart is ineffective on detecting minimal mean deviations. Exemplified by bivariate quality characteristics, we compared the monitoring effects of HotellingT2control chart and new control chart which is called asT2MEWMAcontrol chart. Paper showed the improvedT2MEWMAcontrol chart has smaller average run length than HotellingT2control chart on monitoring minimal mean deviation and that also studied the relationships betweenT2MEWMAcontrol chart’s forgetting factor, sample sizes N and type II error. It indicated the smaller forgetting factor is more sensitive to minimal mean value deviation and that average run length tended to become bigger gradually along with increase of sample sizes N when production process is out of control.
