Abstract
This work presents a partial least square (PLS) based double exponentially weighted moving average controller (d-EWMA) of multiple-input and multiple-output (MIMO) processes subjected to constant or moderate gain shifts disturbance. This study is mainly focused on a new gain monitoring method and a PLS based model updating. It was demonstrated that under the circumstance the variance of the first order difference of the latent control action would be more effective in detecting the gain shifts. The performance improvements are illustrated using a simulation problem from literature and applications to thickness control in a diffusion furnace of a local semiconductor facility. © 2011 Elsevier Ltd.