State-feedback disturbance attenuation for polytopic LPV systems with input saturation

Abstract

This paper proposes a state-feedback control law for linear parameter-varying (LPV) systems with input saturation and disturbances. The proposed control law employs two control parts: a main control part for reducing the restricted L-2 gain from the mismatched disturbance to the controlled output and an extra control part for eliminating the matched disturbance. Owing to this feature, the proposed control law provides a better disturbance attenuation performance than the conventional control law that deals with a unified disturbance regardless of the presence of matched and mismatched disturbances. Further, considering different forms of the feedback gain matrix K (theta(t)) and the Lyapunov function V (x(t)), three types of controllers are proposed. For each type, set invariance and the restricted L-2 gain performance conditions are first formulated in terms of parameterized linear matrix inequalities (PLMIs) and then converted into linear matrix inequalities (LMIs) by using a parameter relaxation technique. Results from the simulation of numerical examples confirm the effectiveness of the proposed controllers. Copyright (C) 2009 John Wiley & Sons, Ltd.