Performance improvement in decentralized adaptive control: a modified model reference scheme

Abstract

A new decentralized model reference adaptive controller is proposed for a continuous time large scale system composed of N interconnected linear subsystems with unknown parameters. In the case where the high frequency gains of the transfer functions of each of the isolated subsystems is known, the new scheme can be used to improve the band transient behavior that typically results from poor knowledge of the subsystem parameters. It is shown that the transient performance improvement has to be traded off against the size of the allowable unmodeled interconnections in such a way that as the unmodeled interconnections disappear, the improvement in transient performance can be made arbitrary. Since each local adaptive scheme uses approximate differentiators, the presence of high frequency sensor noise may impose additional limitations on the effectiveness of the new scheme. >