An Efficient Run-To-Run Controller : ESET

C. Zhang and J. S. Baras

AEC/APC Symposium XIII, Banff, Alberta, Canada, October 6-11, 2001

 

Abstract

The EWMA run-to-run (RtR) controller is easy to deploy and can effectively deal with small disturbances. But it can not compensate for shifts (step disturbances) and large model errors well. The common solution to such a problem is to use the SPC to detect the occurrence of a shift and them remove the cause of the shoft or apply a rapid mode. In this paper, a novel approach to handle shifts and large model errors is proposed: the SVR-MOVE controller is used to compensate for a shift when it is detected. The SVR-MOVE controller is very efficient to handle shifts and large model errors. On the other hand, a well-tuned EWMA controller may outperform a coarsely tuned SVR-MOVE controller when the disturbances are smotth drifts. It is much easier to tune the parameters of the EWMA controler than that of the SVR-MOVE controller. Our new controller, named ESET, has the advantage of both controllers. Simulation shows that the ESET outperforms the EWMA controller and the SVR-MOVE controller in most situations.