Dynamic output feedback for Takagi-Sugeno fuzzy systems subjected to inexact premise variables matching
Fuzzy Takagi-Sugeno; Dynamic Output Feedback, Imperfect premise matching.
This work presents new design conditions of full-order dynamic output feedback controllers for continuous and discrete-time Takagi-Sugeno (T-S) fuzzy systems allowing the selection of premise variables to be used in the control law. The fuzzy output controller is allowed to have a different number of fuzzy rules and a different set of membership functions from the T-S model. This includes the cases of complete or partial immeasurable premise variables. The main aspect of the proposed methodology is to present conditions where the control gains are independent of the premise variables that cannot be measured allowing flexibility for the designer in a realistic output feedback context. Moreover, the design conditions are expressed as linear matrix inequality relaxations combined with scalar parameters that provide extra degrees of freedom. The proposed control methodology also deals with model uncertainties for continuous and discrete-time systems and the use of fuzzy Lyapunov functions. The effectiveness and applicability of the methodology are shown through numerical examples