Backstepping control of polymerization reactor

This paper presents adaptive backstepping methodology for controlling polymerization process under parametric uncertainty and input saturation. In general controlling complex chemical processes is a challenging problem due to the structural mismatch and uncertainty of parameters. Adaptive algorithm, whether linear or non-linear, is an essential tool to control such processes. Normally, nonlinear adaptive controllers are designed based on stability of Lyapunov functions. A recursive backstepping design approach is applied here for constructing Lyapunov functions and designing nonlinear control laws for controlling temperature and monomer concentration of polymerization process. The adaptive algorithm is also able to tackle other parametric uncertainties along with input saturation. The controller structure has a strong disturbance rejection capability and also robust to model uncertainties for polymerization process. A number of parameters are adapted for obtaining better result and the controller gives a stable performance in presence of significant parametric uncertainty. The proposed adaptive controller is capable of handling both matched and unmatched uncertainties.