Back to publications...

Control of plants with changing dynamics using switching model predictive control

Simon Lam and Edward J. Davison

Abstract

A recent problem in adaptive control is the task of controlling a plant which is subject to large structural changes. In this case, it is often assumed the plant can be described by a specified family of models, and that the plant can change from one member of the family of models to some other member of the family of models. Such a system can be controlled by using a set of predefined controllers, and then switching among the controllers to compensate for the change in the plant dynamics. In previous studies, such switching controllers have been found to compensate for changes in the plant dynamics, but the transient response error is typically excessively large, due to the fact that the switching controller, during its "learning period", may produce unstable closed-loop systems, which produce excessively large control signals. In this paper, a new switching controller is described, which uses model predictive control to impose constraints on the control signals. It is shown by simulation that, since the new controller does not produce "peaking" in the control signals, it subsequently solves the above family of controllers switching problem with greatly improved transient behaviour.