Identification of the harmonic transfer functions of a helicopter rotor
Name
48881143-MIT.pdf
Description
Full printable version
Size
4.86 MB
Format
Adobe PDF
Checksum (MD5)
649910bf2d19721ac06e77be5195a7ed
Author(s)
Siddiqi, Afreen, 1977-
Advisor(s)
Steven R. Hall.
Alternative Title
Harmonic transfer functions of a helicopter rotor
Date Issued
2001
Publisher
Massachusetts Institute of Technology
Abstract
Identification of the time periodic dynamics of a helicopter rotor system is necessary for effective controller design and analysis. The transfer properties of a linear time periodic (LTP) system can be described by harmonic transfer functions (HTF) that give the input-output relationship between the Fourier coefficients of the input signal and those of the output signal. A method for identifying harmonic transfer functions of linear time periodic systems is developed in this thesis. The system identification scheme employs a least square estimation technique to obtain HTF estimates. This least square estimation problem is under-determined; therefore, an additional assumption, that the transfer function is smooth, is made in the ID scheme to achieve a well-posed problem. The estimates are calculated by applying a quadratic penalty to the curvature of the transfer functions. The identification scheme has been implemented in MATLAB, and partly coded in C programming language for maximum computational efficiency. This system ID method has been validated with analytical results for a few well-known LTP systems. The validation results show excellent agreement between the identified and analytical transfer functions.
Description
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2001.
Includes bibliographical references (leaves 68-69).
Subjects
Aeronautics and Astronautics.
MIT Department
Massachusetts Institute of Technology. Department of Aeronautics and Astronautics
Terms of Use
M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.
Persistent DSpace Link
