A robust MPC for constrained discrete-time nonlinear systems with additive
uncertainties is presented. The proposed controller is based on the concept of reachable sets, that
is, the sets that contain the predicted evolution of the uncertain system for all possible uncertainties.
If processes are nonlinear these sets are very difficult to compute. A conservative approximation
based on interval arithmetic is proposed for the online computation of these sets. This technique
provides good results with a computational effort only slightly greater than the one corresponding to
the nominal prediction. These sets are incorporated into the MPC formulation to achieve robust
stability. By choosing a robust positively invariant set as a terminal constraint, a robustly stabilising
controller is obtained. Stability is guaranteed in the case of suboptimality of the computed solution.
The proposed controller is applied to a continuous stirred tank reactor with an exothermic reaction.Ministerio de Ciencia y Tecnología DPI-2001-2380-03- 01Ministerio de Ciencia y Tecnología DPI-2002-4375-C02-0
