Dynamic interaction analysis and its application to distillation column control

This paper describes a method to examine the dynamic as well as static interactions among control loops in a multivariable system. The analysis obtains the same results at steady state as that employing the relative gain matrix (Bristol, 1966, Shinskey, 1967). It is demonstrated that a design where the control loops exhibit minimum static interaction is not always the best strategy. This is illustrated through the example of a distillation column, which shows that by using interactive loops, the closed loop poles can be shifted much further to favorable locations of the left complex plane than for the case of minimum steady state interaction loop design.