On-line implementation of nonlinear MPC: an experimental case study

A nonlinear model predictive control algorithm is implemented on-line to co ntrol the liquid level and temperature in a pilot plant CSTR, where an irre versible exothermic chemical reaction is simulated experimentally by steam injection. The dynamic behavior of the pilot plant reactor is represented u sing a mechanistic, first principle model and a comparison between off-line simulation and experimental data is presented. Several sources of model mi smatch and unmeasured disturbances are identified that affect the quality o f the model in representing the reactor dynamics. Despite these mismatches and disturbances, the closed loop system is able to track setpoint changes and reject disturbances quite well. In particular, the NMPC controller is d emonstrated for different tuning parameters and under conditions of constra int saturation at unstable points. (C) 2001 Elsevier Science Ltd. All right s reserved.