Nonlinear Hammerstein model predictive control strategy and its application to pH neutralization process

Industrial processes usually contain complex nonlinearities.For example,the control of pH neutralization processes is a challenging problem in the chemical process industry because of their inherent strong nonlinearity.In this paper,the model predictive control(MPC)strategy is extended to a nonlinear process using Hammerstein model that consists of a static nonlinear polynomial function followed in series by a linear difference equation dynamic element.The calculation strategy of optimal control output based on the static nonlinear polynomial function of the Hammerstein model is presented in detail.Thus a new nonlinear Hammerstein predictive control strategy(NLHPC)is developed.Simulation and control experiments of a pH neutralization process show that NLHPC gives better control performance than the commonly used industrial nonlinear PID(NL-PID)controller.