An Explicit Reference Governor for the robust constrained control of nonlinear systems

Abstract

The Explicit Reference Governor is a simple and systematic approach that provides constraint handling capabilities to pre-stabilized nonlinear systems. The approach consists in translating state and input constraints into a constraint on the value of the Lyapunov function which is then enforced by suitably manipulating the derivative of the applied reference. This paper extends the Explicit Reference Governor approach by addressing its robustness in the presence of external disturbances and parametric uncertainties. Using ISS arguments, it will be shown that the robustness with respect to external disturbances can be ensured by simply restricting the domain of the applied reference. Parametric uncertainties can instead be accounted for using suitable bounds on the Lyapunov function. Numerical simulations show the effectiveness of the proposed method.