Design of switching adaptive laws for the state tracking problem

In this paper, we address the issue of the state tracking control for model reference adaptive control systems. For a given plant with a known structure and unknown parameters, this problem can be solved by designing an adaptive law for traditional model reference adaptive control designs. In this paper, for a plant with finite fixed adaptive laws where none of them guarantees the states of plant track those of the reference model, there are not allowed to design other adaptive law. In this case, we formulate a switching mechanism between these adaptive laws to track the reference model. A sufficient condition is given for the problem to be solvable via the convex combination technique, and a switching law is designed. The theoretical derivations are illustrated by means of an example.