Combines Attitude Control and Energy Storage for Small Satellites using Variable Speed Control Moment Gyroscopes

Abstract

Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to Department of Defense, Washington Headquarters Services, Directorate for Information SPONSOR/MONITOR'S ACRONYM(S) 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)EOARD Unit 4515 BOX 14 APO AE 09421 SPONSOR/MONITOR'S REPORT NUMBER(S)Grant 05-3037 DISTRIBUTION/AVAILABILITY STATEMENTApproved for public release; distribution is unlimited. SUPPLEMENTARY NOTES ABSTRACTThis report results from a contract tasking University of Surrey as follows: The Grantee will investigate three areas concerning energy storage and attitude control systems (ESACS) for small satellites: a.) Use of small satellite reference models to determine the relative scales for a combined variable speed control moment gyroscope (VSCMG) energy storage (ES) system. b.) Explore potential imbalances, derive mathematical descriptions of ESACS-imbalance systems and model the ESACS system in MATLAB/Simulink.. c.) Construct experimental hardware for power conversion demonstration: An experimental VSCMG system will be used to demonstrate combined attitude control and energy storage. The imbalances modeled in (b.) will be replicated in the experimental hardware. Derived control solutions to the imbalance problem will be implemented and validated in the experimental hardware. SUBJECT TERMS Government DisclaimerThe views expressed in this article are those of the authors and do not reflect the official policy or position of the United States Air Force, Department of Defense, or the U.S. Government. AcknowledgementsThe ii Summary This work presents the first known energy storage and attitude control subsystem (ESACS) for small satellites, proving this technology to be viable, applicable to more complex, demanding space missions, and laden with substantial benefits, such as agile slewing, robust singularity avoidance, increased lifetime, mass savings, and favourable peak power density. In capturing the key features of this novel system, it investigates the design sizing, feasibility, mission utility, experimentation, and performance benefits for using variable-speed control moment gyroscopes (VSCMGs) to store and drain energy while controlling satellite orientation.First, a novel optimal ESACS sizing algorithm is developed for a practical, miniature spotlight synthetic aperture RADAR (SAR) space mission. When given a set of small satellite agility and energy storage requirements, the design is cast as a constrained nonlinear programming problem using a performance index constructed from subsystem design margins including the attitude torque, peak power, energy capacity, and subsystem mass margins and solved using a reduced-o...