Maximal error evaluation typed stable model reference adaptive control for periodically linear time-varying systems

A model reference adaptive control system which does not depend on the degree of the plant when the plant is a continuous-time periodically linear time-varying system is presented. The only prior information is the relative degree and the time-varying period. The controller has adjustable scalar functions. The optimal functions of these are directly estimated synchronizing with the time-varying period of the plant by adaptive laws. The main contribution of the paper is the reduction of the computational burden of the adaptive law for the direct function estimation. It is accomplished with the maximum normalized error evaluation adaptive law. The design method and the global stability analysis of the proposed system are shown