Observer-based sampled-data control for uncertain nonlinear systems: Intelligent digital redesign approach

In this paper, we concern an intelligent digital redesign(IDR) method for a Takagi-Sugeno (T-S) fuzzy observerbased output-feedback control (FOBOFC) system which includes parametric uncertainties. The term IDR is to convert an existing analog control into an equivalent digital counterpart via state-matching. The considered IDR problem is viewed as convex minimization problem of the norm distances between linear operators to be matched and its constructive condition is formulated in terms of linear matrix inequalities (LMIs). The main features of the proposed method are that the state estimation error in the plant dynamics is considered in the IDR condition that plays a crucial role in the performance improvement; the uncertainties in the plant dynamics is shown in the IDR condition by virtue of the bilinear and inversebilinear approximation method; finally, the stability property is preserved by the proposed IDR method.