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CONTROL OF SPACECRAFT WITH FLEXIBLE STRUCTURES USING
PULSE-MODULATED THRUSTERS
by
Shalini Reddy
A Dissertation Presented to the
FACULTY OF THE USC GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Ful llment of the
Requirements for the Degree
DOCTOR OF PHILOSOPHY
(MECHANICAL ENGINEERING)
August 2012
Copyright 2012 Shalini Reddy
Object Description
| Title | Control of spacecraft with flexible structures using pulse-modulated thrusters |
| Author | Reddy, Shalini A. |
| Author email | sreddy6@gmail.com;sreddy6@gmail.com |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Mechanical Engineering |
| School | Viterbi School of Engineering |
| Date defended/completed | 2012-06-19 |
| Date submitted | 2012-08-01 |
| Date approved | 2012-08-02 |
| Restricted until | 2012-08-02 |
| Date published | 2012-08-02 |
| Advisor (committee chair) | Flashner, Henryk |
| Advisor (committee member) |
Redekopp, Larry Shiflett, Geoffrey Yang, Bingen Kukavica, Igor |
| Abstract | A methodology for the design of robust control systems for flexible spacecraft undergoing a large angle maneuver using pulse-modulated thrusters is proposed. The need for developing such a methodology stems from the need to reduce the weight of the modern spacecraft and to satisfy strict performance specifications resulting in vibrational modes within the control system bandwidth. Moreover, the discontinuous operation of pulse-modulation may excite large flexible motion that can lead to deterioration of performance, limit cycles, and even instability. Consequently, the current practice of designing the control system using a rigid body model and evaluating performance by simulation using a flexible model is inadequate for the modern spacecraft. In the proposed methodology structural flexibility is included in the control design model thus resulting in control systems with robust stability and improved performance. ❧ This dissertation has two main parts: formulation of flexible spacecraft dynamics performing large angle motion and control system design. The formulation of equations of motion is performed using quasi-coordinates that allow for parameterization of the attitude in terms of Euler-Rodrigues parameters that avoid singularities. Moreover, the formulation is in terms of variables measurable by the control system, such as angular velocities and is in a form that is convenient for establishing closed-loop robust stability. The control law structure proposed here results in guaranteed closed-loop performance in the presence of parameter uncertainties, measurement noise, and command implementation errors. A theorem that guarantees the bounds of trajectory following errors of a spacecraft performing a general translational and rotational motion in three-dimensional space is formulated and proven using Lyapunov stability theory. Finally, a model of a flexible spacecraft is used to demonstrate the performance of a control system developed using the proposed methodology are presented. A number of different maneuvers are studied by simulation showing satisfactory performance in the presence of uncertainties and implementation errors. |
| Keyword | spacecraft; dynamics; control |
| Language | English |
| Part of collection | University of Southern California dissertations and theses |
| Publisher (of the original version) | University of Southern California |
| Place of publication (of the original version) | Los Angeles, California |
| Publisher (of the digital version) | University of Southern California. Libraries |
| Provenance | Electronically uploaded by the author |
| Type | texts |
| Legacy record ID | usctheses-m |
| Rights | Reddy, Shalini A. |
| Access conditions | The author retains rights to his/her dissertation, thesis or other graduate work according to U.S. copyright law. Electronic access is being provided by the USC Libraries in agreement with the author, as the original true and official version of the work, but does not grant the reader permission to use the work if the desired use is covered by copyright. It is the author, as rights holder, who must provide use permission if such use is covered by copyright. The original signature page accompanying the original submission of the work to the USC Libraries is retained by the USC Libraries and a copy of it may be obtained by authorized requesters contacting the repository e-mail address given. |
| Repository name | University of Southern California Digital Library |
| Repository address | USC Digital Library, University of Southern California, University Park Campus MC 7002, 106 University Village, Los Angeles, California 90089-7002, USA |
| Repository email | cisadmin@usc.edu |
| Archival file | uscthesesreloadpub_Volume4/etd-ReddyShali-1110.pdf |
Description
| Title | Page 1 |
| Full text | CONTROL OF SPACECRAFT WITH FLEXIBLE STRUCTURES USING PULSE-MODULATED THRUSTERS by Shalini Reddy A Dissertation Presented to the FACULTY OF THE USC GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Ful llment of the Requirements for the Degree DOCTOR OF PHILOSOPHY (MECHANICAL ENGINEERING) August 2012 Copyright 2012 Shalini Reddy |
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