In this paper, based on Lyapunov-Krasovskii functional approach and the decentralized control theory of interconnected systems, we consider the observer-based control design for a class of fuzzy descriptor interconnected systems. Firstly, the stability conditions of the T-S fuzzy model with a prescribed performance level are provided in theorem 1, but there is no efficient algorithm solving the inequalities. Theorem 2 proposes a single-step method, reducing the conservatism of the conditions. This method overcomes the drawback of the two-step approach in other methods. The stability conditions in theorem 1 are the sufficient and necessary conditions of the ones in theorem 2. The parameters of reliable H ∞ controllers can be found via LMI toolbox in MATLAB software. Finally a numerical example is given to show the validity of the proposed method.

the design of an attitude controller for an unmanned helicopter is addressed. The controller proposed is based on fuzzy PID algorithm, and is used for stable and robust roll, pitch, and yaw control. The fuzzy logic rules are established through a combination of expert knowledge and experiment data which is obtained from a real unmanned helicopter platform. Both the simulation and the experimental results verify the validity of fuzzy PID algorithm which integrates the advantage of fuzzy control and PID control.