Attitude control of a spacecraft using two SGCMGs

This thesis presents new methods for controlling spacecraft using Control-Moment Gyros (CMGs). CMGs generate torque to change and maintain a spacecraft's orientation. The CMG con­trol system is used specifically to provide three-axis altitude stabilization, precision pointing con­trol and maneuvering capability. Two types of CMGs are used in spacecraft attitude control purpose. Classified by the number of gimbals, they are Double Jimbal Control Moment Gyro­scope (DGCMG) and Single Gimbal Control Moment Gyroscope (SGCMG). An SGCMG is often chosen as a torque actuator because an SGCMG has two major advantages over DGCMGs: the torque amplification feature and ease of manufacture. The technical literature discusses altitude control of large spacecraft using three or more SGCMGs. As a case study, the altitude control of rigid spacecraft using two SGCMGs is considered. In this paper, the simplified two-SGCMGs model was made and simulated. The system of interest is nonholonomic and the control strategy is related to motion planning. I demonstrate that often only two SGCMGs are necessary to control the altitude of a spacecraft. This is true when failure of one of the control momentum gyroscopes occurs, two actuators can be used to control the attitude of a rigid spacecraft and arbitrary reorientation maneuvers of the spacecraft can be accomplished. The control strategy where two SGCMGs arc used to control the attitude of the spacecraft was studied and presented.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Mechanical Engineering

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

1998

Author dc:creator

• Kwon, Hyuk-Sang, 1971-

Advisor dc:contributor.advisor

• Seth Lloyd.

• Mechanical Engineering

Statement dc:rights

• 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.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/9725

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/9725