Evaluation of Multiregional Fuzzy-Based pH Cascade Control with ANFIS-Based pH Observer

Abstract

In pH reactors, determination and control of pH is a common problem concerning chemical-based industrial processes due to the non-linearity observed in the titration curve. The researchers introduced a modified multiregional Fuzzy-Based Control System to overcome the complexity of precise control of pH. In order to compensate for the experimental inaccuracies in measurements of pH in-situ values; an observer for pH is implemented using Adaptive Neuro-Fuzzy Inference System (ANFIS). The pH control approach and ANFIS-based observer are integrated in a nonlinear cascade structure to ensure the dynamic modifications and stability enhancement. The cascade structure is designed using a multiregional fuzzy PI controller in the master loop and a Wiener Model-based fuzzy proportional controller as a slave one. The Multiregional Fuzzy Cascade Control (MFCC) structure is developed to implicate the three main regions of the titration curve.