Comparison of Adaptive Control Methods in pH Process Control

In number of research projects various adaptive control methods have been applied to the control of pH with varying success. Recently, intelligent control methods based on fuzzy systems and neural networks have been studied intensively (for example, see Ylén and Jutila, 1996). In some of these studies (see Loh et al, 1995 and Aoyama et al, 1995) nonlinear models are created explicitly for modeling the titration curve of the process liquids; however, this kind of approach is not perhaps most suited for a pH process where continuous and significant changes in pH level and buffering effects in the process liquids occur.