Adaptive control of state constrained nonlinear systems in strict feedback form

In this paper, we propose a systematic approach for the constructive design of adaptive control systems for nonlinear uncertain systems subject to state constraints. The analysis is restricted to a class of nonlinear systems in strict feedback form with respect to the state constraints. A novel adaptive estimation routine is employed to estimate both the unknown parameters and an approximate uncertainty sets, which is decreasing over time. The approximate uncertainty set is utilized to define a sequence of robustly controlled invariant sets which are strictly contained in the feasible set.