Model reference adaptive control for plants with unknown relative degree

Abstract

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. The authors relax this assumption by developing a model reference adaptive controller that 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 a priori knowledge about the plant parameters.