Fiscal Year	2009
Division	Graduate School of Engineering & Applied Science
Department	Mechanical & Aerospace Engineering
Investigator(s)	Agrawal, Jr., Brij N.
Sponsor	National Reconnaissance Office (DoD)
Summary	The objective of this research program is to develop and evaluate techniques for on-orbit system identification and slew maneuver control of flexible spacecraft with Control Moment Gyroscopes (CMGs). The research emphasis is to minimize residual vibrations and slew maneuver time for enhanced acquisition and pointing performance. With the current trend in spacecraft design of increased flexibility, multiple modular bodies, and stringent attitude control accuracy requirements, slew control design may need improvements to accomplish future spacecraft missions. During FY2008, input shaping techniques were investigated for three-axis slew maneuver problems, including the nonlinear term in the spacecraft equation of motion. This approach provides a simple way of designing a slew control within the available momentum space of the CMG array. Experiments using the Bifocal Relay Mirror Spacecraft (BRMS) simulator were also performed. In order to use the full momentum space of the CMG array, solving an optimization problem with nonlinear dynamic equations is required. Slew maneuver control design using a Sequential Linear Programming (SLP) technique was also investigated. In FY2009, The SLP optimization technique and system identification method using a filter bank approach will be extended for three axis rotational flexible spacecraft and will be implemented on the experimental testbed. The adaptive filters will be also investigated in FY 2009. The star tracker sensor will be integrated on the BRMS simulator for accurate determination of the spacecraft attitude.
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Publications	Publications, theses (not shown) and data repositories will be added to the portal record when information is available in FAIRS and brought back to the portal
Data	Publications, theses (not shown) and data repositories will be added to the portal record when information is available in FAIRS and brought back to the portal