Date of Award

3-16-2009

Document Type

Thesis

Degree Name

Master of Science in Astronautical Engineering

Department

Department of Aeronautics and Astronautics

First Advisor

Eric D. Swenson, PhD

Abstract

Optimization of spacecraft attitude maneuvers can significantly reduce attitude control system size and mass, and extend satellite end-of-life. Optimal control theory has been applied to solve a variety of open-loop optimal control problems for terrestrial, air, and space applications. However, general application of real-time optimal controllers on spacecraft for large slew maneuvers has been limited because open-loop control systems are inherently vulnerable to error and the computation necessary to solve for an optimized control solution is resource intensive. This research effort is focused on developing a near real-time optimal control (RTOC) system for spacecraft attitude maneuvers on the Air Force Institute of Technology's 2nd generation simulated satellite, SimSat II. To meet the end goal of developing a RTOC controller, necessary preliminary steps were completed to accurately characterize SimSAT II's mass properties and attitude control system. Using DIDO, a pseudospectral-based optimal control solver package, to continuously solve and execute a sequence of optimized open-loop control solutions in near real-time, the RTOC controller can optimally control the state of the satellite over the course of a large angle slew maneuver. In this research, simulation and experimental results clearly demonstrate the benefit of RTOC versus other non-optimal control methods for the same maneuver.

AFIT Designator

AFIT-GA-ENY-09-M06

DTIC Accession Number

ADA496781

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