Some further results on adaptive λ-tracking for linear systems with high relative degree

Several adaptive controllers which universally achieve the so-called λ-tracking have been proposed in the literature. From a practical point of view, previous results are not usable for systems with a high relative degree because of bad numerical conditioning. The paper presents a modified approach overcoming this numerical problem while achieving the same robust stability properties. Stability and convergence of the adaptation is proven for tracking a large class of reference trajectories. The design of the controller is very simple and intuitive, only few parameters have to be tuned and little structural information about the system to be controlled is needed