Robust output-regulation for uncertain linear systems with input saturation

The aim of this study is to design a robust output-based control to regulate the output for a class of linear systems with input saturation and affected by parameter uncertainties and external disturbances. The proposed robust control approach is composed of a homogeneous observer and a linear control law. The design and convergence analysis of the homogeneous observer is based on the implicit Lyapunov function theorem guaranteeing the finite-time convergence of the state estimation error to a neighbourhood of the origin. The linear control law, that uses the estimated states and takes into account the saturated input constraint, is designed based on the attractive ellipsoid method and a barrier Lyapunov function approach. The synthesis of the robust-output based control is given in terms of linear matrix inequalities. Simulation results are presented to illustrate the feasibility of the proposed robust control approach.