An application of the RMMAC methodology to an unstable plant

In this paper we extend and generalize previous work on Robust Adaptive Control of uncertain plants using Multiple Models (the RMMAC methodology) [1]. We formulate and study the problem of robust adaptive control of open-loop unstable plants with structured and unstructured uncertainty in the presence of external disturbances, an issue that poses considerable theoretical and practical challenges. In particular, we show how a slight modification of the technique introduced in previous work on the RMMAC for stable plants yields a methodology that can deal with unstable plants. A design example and computer simulations are presented and discussed.