A cost-effective methodology for a run-by-run EWMA controller

In this paper, we present a cost-effective methodology for a run-by-run EWMA controller. This controller is an integrated approach that combines the advantages of statistical process control and feedback control. It adjusts the equipment settings only when the control chart detects an abnormal trend. Using simulations, we take into consideration the control sensitivity, robustness, and adjustment number required to determine an optimal weight for a minimum cost. As the simulation results demonstrate, the cost-effective run-by-run controller is able to keep drifting process outputs close to the target with only few runs of adjustment.