Adaptive control for uncertain linear systems using switching between multiple controllers

This paper deals with the problem of designing an adaptive control system in order to reduce conservatism inherent in a robust control scheme which consists of single and fixed gain controllers when the linear state-space model of the plant contains unknown parameters which vary within certain prescribed bounds. The whole possible parameter space is divided into several parameter subspaces, and multiple controllers are established for the corresponding parameter subspace, in which each one is designed so as to achieve the minimum quadratic cost bound. Furthermore, an on-line switching method among multiple controllers is presented, by which the true parameter subspace of the plant can be detected in a real-time fashion and at the same time an appropriate controller is selected