An LMI approach to H∞ robust control with constraints for system with linear fractional uncertainty

This paper addresses the H_∞ design problems of state-feedback controllers with closed-loop pole placement and variance constraints for continuous system with linear fractional uncertainty. It is required that the closed-loop poles lie in a specified disk and steady-state variances is less than a prescribed upper bound. It is proved that the existence condition of such controllers is equivalent to the LMIs feasibility. A parameterized controller is characterized in terms of the feasible solutions to the LMIs.