Stability in qualitative model reference adaptive control

In this paper a Model Reference Adaptive Control system is presented which is based on qualitative (less precise) models. These qualitative models can represent the underlying physical system accurately even with low order models. Further, multi-valued performance specifications can be expressed explicitly by a qualitative model in the form of a reference model. The Qualitative Model Reference Adaptive Control system utilises a fuzzy qualitative simulation method to represent this reference model. These fuzzy dynamical models are of an analytic form and allow system analysis to be based on fuzzy interval analysis. Therefore, stability of the adaptive loop within Qualitative Model Reference Adaptive Control is based on results of robust parametric stability using interval models.