Semi-global output regulation for linear systems with input saturation by output feedback CNF control

This paper proposes an output feedback composite nonlinear feedback (CNF) control method for semi-global output regulation problem of linear systems with input saturation. Based on the state feedback CNF control law for the semi-global output regulation problem, an observer is designed to construct an output feedback CNF control law that also solves the semi-global output regulation problem. A sufficient solvability condition for semi-global output regulation problem is established in the paper. It is shown that the solvability condition of the semi-global output regulation problem by output feedback CNF control is the same as that of the semi-global output regulation problem by output feedback linear control. Thus, the CNF control technique can be applied to improve the transient performance for the semi-global output regulation problem. The improvement of the transient performance is illustrated by a regulation problem of a benchmark translational oscillator with rotational actuator system.