ADAPTIVE INPUT-OUTPUT LINEARIZATION OF A PH NEUTRALIZATION PROCESS

Adaptive non-linear control strategies for a pH neutralization process are developed and evaluated via simulation. A non-adaptive non-linear controller is designed using a modified input-output linearization te chnique which accounts for the implicit output equation in the reactio n invariant model. For simplicity the reaction invariants are assumed to be available for feedback. Because the model exhibits significant t ime-varying behaviour, the input-output linearizing controller is comb ined with non-linear parameter estimators which account for unmeasured buffering changes. Simulation results demonstrate that a novel indire ct adaptive strategy is most suitable for experimental implementation where the reaction invariants must be estimated and sampling is requir ed. (C) 1997 by John Wiley & Sons, Ltd.