Softly Switched Model Predictive Control for Control of Integrated Wastewater Treatment Systems at Medium Time Scale

Analysis and Design of Softly Switched Model Predictive Control

“…With the increasing use of MPC into large scale and complex hierarchical systems, the demand to use multiple MPCs to meet different control objectives under different operating scenarios arises (Grochowski, et al, 2004a). The so called softly switched MPC (SS-MPC) means such an approach that can make the switch between two MPCs smooth by contrast with hard switching whose switching performance is often unsatisfactory especially in the scenarios where the input/state constraints are changing from very tight constraints to much looser ones.…”

“…The so called softly switched MPC (SS-MPC) means such an approach that can make the switch between two MPCs smooth by contrast with hard switching whose switching performance is often unsatisfactory especially in the scenarios where the input/state constraints are changing from very tight constraints to much looser ones. A real life application can be found in (Grochowski, et al, 2004b). Although the issues of stability of constrained model predictive control for linear time-invariant (LTI) systems have been deeply investigated (Zheng and Morari, 1995;Mayne, et al, 2000;Primbs and Nevistic, 2000), the research on the stability of switching among multiple constrained predictive controllers is still an open area which incorporates fundamental problems both in the MPC area and in the switched system field (Grochowski, 2003).…”