Improved adaptive fuzzy control for MIMO nonlinear time-delay systems

This paper presents an improved observer-based indirect adaptive fuzzy control scheme for multiinput-multioutput (MIMO) nonlinear time-delay systems. The control scheme synthesizes adaptive fuzzy control with adaptive fuzzy identification. An observer is designed to observe the system state, and an identifier is developed to identify the unknown parts of the system. The update laws for parameters utilize two types of errors in the adaptive time-delay fuzzy logic systems, the observation error and the identification error. Performance analysis proves the superiority of the update laws in terms of faster and improved tracking and parameter convergence. Simulation results of two-link manipulator demonstrate the effectiveness of the improved control scheme.