A Framework for the Analysis of Airframe/Engine Interactions and Integrated Flight/Propulsion Control

Potential sources of airframe/engine interactions are explored for aircraft subject to the study of integrated flight/propulsion control. A quasi-linear framework for the analysis of these dynamical interactions between the airframe and engine systems is presented. This analysis can be used to quantify, in a meaningful way, the magnitude of the interactions between the airframe and engine systems, determine if these interactions are significant to warrant further consideration in the control law synthesis, and if so, what are the critical frequency ranges where problems may occur due to these interactions. Justification for the use of this method, along with the assumptions, conditions and restrictions that apply are discussed. Sample results of this analysis are used to illustrate issues brought forth in its development. Also, a comparison is made between another frmework for analysis in integrated flight and propulsion control, reported elsewhere, and the framework presented in this paper.