Output feedback control for T-S fuzzy models with unknown inputs

This paper proposes an observer-based controller to stabilize Takagi-Sugeno (T-S) fuzzy models with unknown inputs, in which the unknown inputs need not satisfy the so-called observer matching condition. Firstly, an unknown input observer (UIO) is constructed to estimate the system states and unknown inputs, the observer gains are given in linear matrix inequality (LMI) terms. The controller is then developed under the framework of backstepping design, and a first-order filter is employed in each step of the recursive structure. The system stability is investigated based on the Lyapunov theory, and uniform boundedness property of the closed loop system is achieved. Finally, numerical simulation results are presented to illustrate the effectiveness of the proposed method.