General controllability and observability tests for Takagi-Sugeno fuzzy systems

An approach for investigating controllability and observability properties in Takagi-Sugeno (TS) fuzzy systems is given. The proposed method is independent of the number of fuzzy rules acting at the same instant and independent of the number of inputs and outputs included in the TS fuzzy model. Therefore, it can be applied to a wide class of fuzzy systems. The analysis relies on the solution of a set of symbolic simultaneous equations with the fuzzy weights as the unknowns of such equations.