H∞ design for systems with input saturation: an LMI approach

A design technique is proposed to improve disturbance attenuation for systems with input saturation. The main results of the paper rely on a multiobjective approach which combines the quadratic stabilization design technique with constraint on the input saturation, which is taken into account using the star-norm approach. For the full state feedback problem, the sufficient conditions for feasibility are expressed in terms of linear matrix inequalities (LMIs). For the output feedback design, we assume the controller to have an observer-based structure. The sufficient conditions for the output feedback controller to recover the full state problem are also given in terms of LMIs. The feasibility of the high performance output feedback controller is guaranteed if the system can satisfy certain conditions. The validity and applicability of the proposed method are illustrated by two examples