Computational approach for adjudging Feasibility of Acceptable Disturbance Rejection

The achievable control quality (“controllability”) is limited by the plant itself, independent of the controller design algorithm. A key issue in the controllability analysis is to decide upfront if there exists a controller that can reduce the effect of disturbances to an acceptable level with the available manipulated variables. When such a controller exists, the process is said to have “operability” (Georgakis et al., 2004). A closely related problem is that of steady-state “flexibility” (Swaney and Grossman, 1985). In this paper, we consider the following problem posed by Skogestad and Wolff (1992):