Prescribed Finite-Time Adaptive Fuzzy Control via Output Feedback for Output-constrained Nonlinear Systems

A new and efficient output-feedback adaptive backstepping control strategy is developed to realize a finite-time output tracking control task for nonlinear output-constrained systems. The main characteristic of this strategy is to construct an asymmetric barrier Lyapunov function based on the performance functions and error variable to achieve finite-time tracking control. Because the system states are unknown, fuzzy state observer is set up to reconstruct the system states. Consequently, an observer-based fuzzy adaptive output-feedback controller is presented. The proposed control strategy ensures that the output tracking error meets the preassigned precision level throughout a pre-given time period, meanwhile, the output variable complies with time-varying restrictions for all time and other closed-loop signals are bounded. Lastly, two examples are employed for numerical simulation research to reveal the feasibility and availability of the developed control strategy.