Model Reference Adaptive Control for Plants with Unknown Relative Degree

One of the basic assumptions in stable model reference adaptive control is that the relative degree n* of the modeled part of the plant is known exactly and matches that of the reference model. In this paper we relax this assumption by developing a model reference adaptive controller which requires only an upper bound for n*. This is done at the expense of updating additional parameters and using a projection algorithm to project some of the estimated parameters on appropriate convex sets in the parameter space. These convex sets can be developed without using any apriori knowledge about the plant parameters.