Synthetic charts to control bivariate processes with autocorrelated data

In this study, we propose the use of simultaneous (X) over bar charts to control bivariate processes with autocorrelated data. The first set of (X) over bar charts is side-sensitive with regard to the same variable (SV (X) over bar charts) and the second one is side-sensitive with regard to both variables (BV (X) over bar charts). The Markov chain approach was used to obtain the steady-state properties of the (X) over bar charts. In comparison with the standard synthetic T-2 chart, the SV and the BV charts signal faster in a wide variety of disturbances, except when the variables are high correlated. The BV charts are simpler and signal faster than the SV charts. (C) 2016 Elsevier Ltd. All rights reserved.