Indirect adaptive backstepping control of a pH neutralization process based on recursive prediction error method for combined state and parameter estimation

A novel nonlinear adaptive technique has been proposed for control of a pH neutralization process. For this, a standard nonlinear dynamic pH neutralization model was parametrized assuming that some key parameters of the buffer and feed streams, which sensitively affect the titration curve, are unknown. On this model, an indirect adaptive backstepping controller is designed by combining a backstepping controller and the recursive prediction error method for real-time parameter and state estimation. Through simulation studies, it has been shown that the estimated parameters and state variables are in good agreement with the actual values and that the proposed adaptive controller has excellent tracking and regulation performance.