Robust Controller Using Polynomial Chaos Theory

This paper describes the application of Polynomial Chaos Theory, PCT, to create a robust controller. It describes a two-degrees-of-freedom controller that uses the measured states as well as the estimated uncertainty of the measured states as feedback. Using the measured states as feedback rejects disturbances, while using the feedback of the uncertainty states compensates for the inadequacies of the feed-forward gain in the presence of parametric changes. The PCT controller utilizes a PCT observer to estimate the uncertainty on the measured states. Because the uncertain states are estimated in closed loop, run-time changes in parameters directly affect the uncertainty estimation. Therefore, estimating uncertainty can compensate for parameter changes in the model. This paper provides experimental results of this novel controller design methodology using a buck converter as an example.