ADAPTIVE-CONTROL FOR PH SYSTEMS

In this study, an adaptive pH controller is proposed to control the pH process efficiently. Dissociation constant and total ion concentratio n of a fictitious weak acid are estimated to approximate the equilibri um characteristic of the pH process by the on-line recursive least-squ ares method and the pH value is controlled by a nonlinear proportional -integral (PI) controller using the estimated process parameters. Simu lation results show that the proposed control strategy promises to han dle both the nonlinearities and time-varying characteristics of the pH process. (C) 1998 Elsevier Science Ltd. All rights reserved.