Abstract
In this paper, a model reference adaptive control system (MRACS) for single-input single-output linear discrete systems is considered. Ionescu and Monopoli already proposed the discrete MRACS using state variable filters and an augmented error signal, which is regarded as a discrete version of Monopoli's continuous MRACS. The positive real concept is not utilized in their adaptive system, and as a result a very complex Liapunov function was needed to assure the stability of the adaptive scheme. From this point of view, the general model reference adaptive scheme using the positive real concept is proposed in this paper. Furthermore, a very simple adaptive system can be derived as a special case of this MRACS. This MRACS does not include the state variable filters and an error augmenting dynamics. Since in this MRACS only past input and output signals of the model and the plant are used, it is of great advantage to construct practically.
