Discretisation of continuous-time T-S fuzzy system: global approach

A new discretisation technique (so-called global discretisation approach) for the continuous-time Takagi-Sugeno (T-S) fuzzy system is suggested. The proposed global discretisation method takes account of the non-linear behaviour among the fuzzy rules. The authors´ main idea is to utilise the dual-rate sampling scheme. The proposed approach is to discretise the overall dynamics of the fuzzy system in the slow-rate sampling period and then to perform the approximation for the polytopic structure in the fast-rate sampling period. In addition, to reduce the number of the IF-THEN rules, the convex minimisation problem is formulated in terms of the linear matrix inequalities. A chaotic Lorenz system is used to show the feasibility of the proposed discretisation method.