Title page for ETD etd-01072002-135844

Type of Document

Dissertation

Author

Tuzcu, Ilhan

Author's Email Address

ituzcu@vt.edu

URN

etd-01072002-135844

Title

Dynamics and Control of Flexible Aircraft

Degree

PhD

Department

Mechanical Engineering

Advisory Committee

Advisor Name	Title
Meirovitch, Leonard	Committee Chair
Inman, Daniel J.	Committee Co-Chair
Ahmadian, Mehdi	Committee Member
Librescu, Liviu	Committee Member
Wicks, Alfred L.	Committee Member

Keywords

Multidisciplinary Formulation
LQG Control
Extended Aeroservoelasticity
Perturbation Approach
Flexible Aircraft Dynamics

Date of Defense

2001-12-19

Availability

unrestricted

Abstract

This dissertation integrates in a single mathematical formulation the disciplines pertinent to the
flight of flexible aircraft, namely, analytical dynamics, structural dynamics, aerodynamics
and controls. The unified formulation is based on fundamental principles and incorporates
in a natural manner both rigid body motions of the aircraft as a whole and elastic deformations
of the flexible components (fuselage, wing and empennage), as well as the aerodynamic,
propulsion, gravity and control forces. The aircraft motion is described in terms of three
translations (forward motion, sideslip and plunge) and three rotations (roll, pitch and yaw)
of a reference frame attached to the undeformed fuselage, and acting as aircraft body axes,
and elastic displacements of each of the flexible components relative to corresponding body
axes. The mathematical formulation consists of six ordinary differential equations for the
rigid body motions and one set of ordinary differential equations for each elastic displacement.
A perturbation approach permits division of the problem into a nonlinear "zero-order Problem"
for the rigid body motions, corresponding to flight dynamics, and a linear "first-order
problem" for the elastic deformations and perturbations in the rigid body translations and
rotations, corresponding to "extended aeroelasticity." Due to computational speed advantages,
the aerodynamic forces are derived by means of strip theory. The control forces for the flight
dynamics problem are obtained by an "inverse" process. On the other hand, the feedback control
forces for the extended aeroelasticity problem are derived by means of LQG theory. A numerical
example corresponding to steady level flight and steady level turn maneuver is included.

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