High-Fidelity Simulation for Identification of Steady and Dynamic Transport Aircraft Derivatives

Abstract

This work describes an approach to identify flight mechanic characteristics of a flexible jet transport aircraft based on high fidelity aerodynamics. A parameter identification process uses time histories of a multidisciplinary flight dynamics simulation including rigid body and elastic degrees of freedom together with the time dependent control surface inputs to estimate steady and dynamic derivatives. The focus is on the identification of the longitudinal parameters of the aircraft for which the elevator and the horizontal tail plane are deflected with wavelet-based inputs of selected frequencies and amplitudes. The total flight time is in the order of a few seconds only, appropriate modification of the inertia properties of the aircraft further reduces the computational costs. The approach for the multidisciplinary flight dynamics simulations are described in detail, including the methods for the high fidelity, CFD-based aerodynamics, the flight mechanics, and the structural dynamics. The test case is a narrow-body jet airliner for which the simulation models and the results of two flight dynamics simulations for system identification as well as a gust load alleviation scenario are presented.