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A master's thesis from Aalborg University
Book cover


Accurate Three-Axis Control of Spacecraft with Non-Uniform Mass Distribution

Term

4. term

Publication year

2023

Submitted on

Pages

64

Abstract

This thesis is done in collaboration with Danish satellite manufacturer Space Inventor. A method of performing a transformation allowing for principle axis control in the satellite body was proposed by the company as a way of counteracting the non-homogeneous mass distribution of a satellite. This was attempted using both a PD and LQR approach. Furthermore, a comparison with between the proposed method and applying control directly in the body frame was done through a Monte-Carlo simulation, and their performance was measured with a quadratic cost function. From the results, the principal axis control was deemed to perform no better than the body frame implementation, and the results shown in both case scenarios even favored the body frame over the principal axis controller. A different unsolicited approach presented to Space Inventor was that of Model Reference Adaptive Control (MRAC), which was later attempted. The implementation showed satisfactory reference model tracking and matched uncertainty cancellation in the linear domain. Future work however, revolves a few modifications in order to make the controller also applicable in the nonlinear case.