A separation principle for non-UCO systems: The jet engine stall and surge example

The problem of controlling surge and stall in jet engine compressors is of fundamental importance in preventing damage and lengthening the life of these components. In this theoretical study, we illustrate the application of a novel output feedback control technique to the Moore-Greitzer mathematical model for these two instabilities assuming that the plenum pressure rise is measurable. This problem is particularly challenging since the system is not uniformly completely observable and, hence, none of the output feedback control techniques found in the literature can be applied to recover the performance of a full state feedback controller.