Non-fragile H∞ output tracking control for fishpond physiology ecosystems

Using the delta operator approach, the problem of designing non-fragile H_∞ output tracking controller for fishpond physiology ecosystems is studied in a unified framework. The purpose of this problem addressed is to design a output tracking controller such that the closed-loop system is asymptotically stable and achieves tracking control performance for all admissible additive controller gain variations. The considered controller gain variation type is more general than the existing norm-bounded gain uncertainties. An improved version of bounded real lemma is also presented. A sufficient condition for the existence of such a controller is obtained in terms of linear matrix inequality (LMI) technique. Finally, a numerical example based on linearize model of a fishpond physiology ecosystem is given to illustrate the effectiveness of the proposed method.