Abstract
This paper presents a scheme for designing a hyperstable discrete model reference adaptive control system, by using the augmented error signal concept proposed by Monopoli.
In our scheme, the error equation between the reference model and the plant outputs is transformed into an equivalent feedback system composed of a first order linear part and a nonlinear time varying part, by introducing an augmented error signal. The hyperstability of the adaptive control system can be assured by letting the transfer function of the linear part be strictly positive real and controlling the adjustable parameters according to an adaptive law. The condition for strictly positive real transfer function can be easily satisfied since the transfer function is of a first order in our scheme. The adaptive law can be implemented by solving a third order algebraic equation of the augmented error signal at each sampling instant. The control input to the plant is adaptively synthesized by employing the adjustable parameters and available signals in the system. The usefulness of the proposed scheme is demonstrated by the computer simulation carried out for a second order plant.
