ADAPTIVE ROBUST-CONTROL UNDER UNKNOWN PLANT ORDERS

A robust indirect adaptive controller under additive and parametric di sturbances is introduced in this paper. The orders and time delay of t he plant are assumed to be unknown apart from their known upper bounds . It is also assumed that a robust linear controller of the plant can be defined for known parameters, model orders and time delay. The robu st adaptive controller switches between model structures depending on an overall criterion of performance. It is not only proved that the ad aptive control scheme is stable but that its asymptotic performance ca n be set arbitrarily near to the performance achievable for a known pl ant. Finally, a simulation illustrates the performance of the scheme. (C) 1998 Elsevier Science Ltd. All rights reserved.