L1 adaptive output feedback controller for nonlinear systems in the presence of unmodeled dynamics

This paper presents the L₁ adaptive output feed-back controller for a class of uncertain nonlinear systems in the presence of time and state dependent unknown nonlinearities, and multiplicative unmodeled dynamics. The L₁ adaptive controller ensures uniformly bounded transient and asymptotic tracking for system´s both signals, input and output, simultaneously. The performance bounds can be systematically improved by increasing the adaptation rate.