A novel H∞ tracking-based decentralized adaptive output feedback fuzzy controller is proposed for a class of
large-scale MIMO uncertain nonlinear systems whose states are not measurable. By the filtering of the observation error
vector, the strictly positive-real condition is guaranteed to hold such that the proposed feedback and adaptation mechanisms
are implementable. By using fuzzy systems, the proposed H∞ tracking-based decentralized adaptive fuzzy control scheme
is applicable to a relatively general large-scale nonlinear systems. The controller singularity is addressed under a united
framework. It is proved that the closed-loop large-scale systems are stable, and the output errors have H∞ tracking
performance. Simulation results show the effectiveness of the controller design.