Performance recovery of intelligent digital redesign for observer-based output feedback under immeasurable premise variables

This study discusses an intelligent digital redesign (IDR) for observer-based output-feedback controllers in Takagi-Sugeno form under immeasurable premise variables. A delta operator that asymptotically connects an analogue control system with its discrete-time model is adopted. The condition for the IDR problem with stability is proposed in terms of matrix inequality. The authors show that the proposed IDRed sampled-data controller recovers the analogue control performance from the perspective of the closed-loop trajectory under the fast sampling limit.