Constrained output feedback control of a multivariable polymerization reactor

A multivariable nonlinear control strategy which accounts for unmeasured st ate variables and input constraints is developed for the free-radical polym erization of methyl methacrylate in a continuous stirred tank reactor. Mono mer concentration and reactor temperature are controlled using a technique which combines nonlinear input-output decoupling and linear model predictiv e control. Input constraints are handled explicitly by applying linear mode l predictive control to the constrained linear system obtained after feedba ck linearization and constraint transformation. Unmeasured initiator and so lvent concentrations are accounted for by treating the live polymer concent ration as an unknown parameter which is estimated on-line. The performance of the control strategy is compared to other nonlinear control techniques t hrough closed-loop simulations.