TY - JOUR
T1 - A multivariate double EWMA process adjustment scheme for drifting processes
AU - Del Castillo, Enrique
AU - Rajagopal, Ramkumar
N1 - Funding Information:
Work on this paper was partially funded by NSF grant OMI 9996031. The authors wish to thank the careful reviews of two anonymous referees that resulted in an improved presentation of our research.
PY - 2002/12
Y1 - 2002/12
N2 - The "predictor-corrector" feedback controller, a process adjustment scheme proposed for semiconductor manufacturing run-to-run processes that drift, is extended to the multiple-input-multiple-output case. The controller is based on two coupled multivariate Exponentially-Weighted-Moving-Average (EWMA) equations, thus its performance depends on the choices of EWMA weight matrices. Stability conditions are given for a pure gain process adjusted with a MIMO double EWMA (dEWMA) controller. It is shown that the stability conditions are invariant with respect to various realistic drift disturbance models. Recommendations on how to choose the EWMA weight matrices are given. An analysis is conducted to assess the impact of errors in the estimates of the process gains. The proposed MIMO dEWMA feedback controller is compared to the common practice of using multiple single-input-single output dEWMA controllers running in parallel.
AB - The "predictor-corrector" feedback controller, a process adjustment scheme proposed for semiconductor manufacturing run-to-run processes that drift, is extended to the multiple-input-multiple-output case. The controller is based on two coupled multivariate Exponentially-Weighted-Moving-Average (EWMA) equations, thus its performance depends on the choices of EWMA weight matrices. Stability conditions are given for a pure gain process adjusted with a MIMO double EWMA (dEWMA) controller. It is shown that the stability conditions are invariant with respect to various realistic drift disturbance models. Recommendations on how to choose the EWMA weight matrices are given. An analysis is conducted to assess the impact of errors in the estimates of the process gains. The proposed MIMO dEWMA feedback controller is compared to the common practice of using multiple single-input-single output dEWMA controllers running in parallel.
UR - https://www.scopus.com/pages/publications/0036887726
UR - https://www.scopus.com/pages/publications/0036887726#tab=citedBy
U2 - 10.1023/A:1019614312908
DO - 10.1023/A:1019614312908
M3 - Article
AN - SCOPUS:0036887726
SN - 0740-817X
VL - 34
SP - 1055
EP - 1068
JO - IIE Transactions (Institute of Industrial Engineers)
JF - IIE Transactions (Institute of Industrial Engineers)
IS - 12
ER -