Abstract
We propose a decentralized high gain adaptive control for a stabilization of interconnected subsystems. Backstepping is applied in order to relax the relative degree constraint. The assumptions for the plant are that each subsystem is minimum-phase and its relative degree is known, and that the interconnection satisfies the so-call matching condition. Because a certain failure of a local controller can be modelled by a change of interconnections, we propose a decentralized adaptive control system which is robust for the uncertainty of interconnections. In order to avoid an unnecessary high gain feedback, we adopt the σ-modified adaptive law. Fault tolerance of the proposing system is proved by showing that a certain class of failure does not change the form of a mathematical model of a decentralized system and that the proposing controller stabilizes the system represented by the mathematical model. Finally, we show a numerical result in order to illustrate the fault tolerance of the system.
