A Systematic Approach to Fuzzy-model-based Robust H_∞ Control Design for a Quadrotor UAV Under Imperfect Premise Matching

In this paper, a systematic procedure to design a robust H_∞ controller for a quadrotor unmanned aerial vehicle is proposed. To do this, the nonlinear dynamic behavior of the quadrotor attitude system is represented as the Takagi–Sugeno (T–S) fuzzy model. Using the derived T–S fuzzy model, a sufficient condition guaranteeing the asymptotic stability and H_∞ disturbance attenuation performance is proposed based on an linear matrix inequality. Unlike the previous studies employing the parallel-distributed-compensation concept, in this paper, the robust H_∞ controller is designed under the imperfect premise matching condition in which the fuzzy controller uses the different membership functions from those of the fuzzy system. Thus, compared to the conventional methods, the hardware implementation cost of the proposed fuzzy controller is decreased even if the membership functions of the fuzzy system are complicated. Finally, some numerical examples are given to show the effectiveness of the proposed method.