Tube-based model predictive control for nonlinear systems with unstructured uncertainty

This paper extends tube-based model predictive control methodology to the control of nonlinear systems with unmodelled dynamics. The problem of obtaining robustness against unstructured uncertainty is converted into the easier problem of achieving robustness against an (additional) bounded disturbance while satisfying an (additional) output constraint. The bound on the disturbance and the output constraint depend on the magnitude of the uncertainty. Robustness against the uncertainty is achieved by using tube-based model predictive control. Simulation experiments concerning the control of a solar collector plant illustrate the effectiveness of the proposed control strategy.