REDUCED-ORDER AEROELASTIC MODELS VIA DYNAMIC RESIDUALIZATION

The accuracy of the mathematical models for aeroelastic analysis, design, and simulation is increased with the number of vibration modes chosen to represent the structure. However, the associated increase in the model size adversely affects calculation efficiency. The purpose of this work is to present a dynamic residualization method with which important structural and unsteady aerodynamic effects associated with high-frequency vibration modes are retained without increasing the model size. The formulation is based on state-space equations of motion where the unsteady aerodynamic force coefficients are represented by a minimum-state rational approximation function. The resulting model has constant coefficients and is compatible with time-domain simulation techniques and with modern control methods. The analytical development and a numerical example that employs a realistic aircraft model are presented. Comparisons of the reduced-order model errors with those obtained by mode truncation and by static residualization show that the dynamic residualization yields significantly more accurate models than those obtained by the other reduction techniques. © 1990 American Institute of Aeronautics and Astronautics, Inc., All rights reserved.