Date of Award

3-2022

Document Type

Thesis

Degree Name

Master of Science

Department

Department of Aeronautics and Astronautics

First Advisor

Robert A. Bettinger, PhD

Abstract

Impulsive thrusters on small satellites, such as CubeSats, are typically used for attitude control. However, to become more agile, small CubeSats must also look to propulsion systems utilizing impulsive thrusters, such as cold-gas, for translational maneuvers. The combined thrust vector is often misaligned with the system's center of mass resulting in a disturbance torque. This must be counteracted by either an attitude determination and control system (ADCS), additional thrusters, or a control method to keep the satellite's attitude at or near equilibrium. Nonlinearities generated by the impulsive maneuvers are overcome via control techniques explored in this research to include on-off control, sliding mode control, and model reference adaptive control (MRAC). These methods were then compared to a baseline test without thruster modulation, where the reaction wheels must de-saturate prior to continuing the maneuver. For a 1.5 m/s delta-v maneuver, the nonlinear control techniques completed the maneuver nearly 100 times faster than the baseline, while improving pointing accuracy throughout the burn by up to 5%.

AFIT Designator

AFIT-ENY-MS-22-M-285

DTIC Accession Number

AD1175598

Included in

Astrodynamics Commons

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