Non-certainty equivalent practically adaptive control for high-order lower triangular systems

A new adaptive control design method based on dynamic scaling and filter for high-order lower triangular system is given, which does not satisfy the certainty equivalence principle. The proposed practically adaptive state feedback controller that ensures all signals of closed-loop systems are globally bounded while keeping the output tracking error to an arbitrary small neighbourhood of the origin simultaneously. The proposed method relies on a novel parameter estimator proposed in Karagiannis & Astolfi (2008, Syst. Control Lett., 57, 733–739). Finally, a numerical example is given.