Output feedback controllers for disturbance attenuation with bounded control

A new design technique is proposed to improve disturbance attenuation for systems with bounded control. The main results of this paper rely on a multiobjective approach which combines the quadratic stabilization design technique with constraints on inputs. The sufficient conditions for feasibility of a full-state feedback compensator are expressed in terms of linear matrix inequalities (LMI). For output feedback problem, two types of compensator structure are studied. The first structure involves a linear compensator whose control command is the input to a saturation block. The results for this type of compensator are generally non-convex. However, the non-convexity can be avoided by assuming the compensator to have a certain structure. The second structure studied uses a nonlinear compensator where the nonlinearity enters directly in the compensator dynamics. The search for the parameters of this type of compensator is convex