Stable adaptive controller design--Direct control

This paper deals with the design of stable adaptive controllers using a model reference approach. A systematic procedure is developed using the concept of positive realness and is generalized to arbitrarily located coutrol parameters. For plants with poles and zeros, the uniform asymptotic stability in the large of the adaptive loop is demonstrated. For plants with zeros the stability problem is clawed and is stated as a conjecture. Simulation studies of the adaptive control of both stable and unstable plants are included towards the end of the paper.