Nonlinear predictive control of an exothermic CSTR using recursive quadratic state space models

The possibility of using a discrete quadratic perturbation model for approximating nonlinear plant dynamics in the neighborhood of the operating point is explored in this paper. A method is evolved for computing the model coefficients using first and second order sensitivity equations. The proposed model is further used to develop a nonlinear model predictive control algorithm. The performance of the proposed control algorithm is demonstrated by simulating a benchmark CSTR control problem characterized by the change in the sign of the steady state gain in the operating region