Asymptotic H∞ disturbance attenuation based on perfect observation

This paper proposes a design method of controllers which ensure internal stability and attain asymptotically H^∞ disturbance attenuation. The design procedure developed in this paper consists of two steps: 1) design an H^∞ state feedback control via an algebraic Riccati equation approach; 2) under a certain minimum phase condition, recover the achievable performance asymptotically by applying high-gain observers. We make use of the perfect observation for the design of high-gain observers. Further it is shown that the asymptotic recovery can be attained by using reduced-order observers, provided there is no direct feedthrough of controls and disturbances in observations.