MAGNETIC FIELD MODEL IMPLEMENTATION AND ITS APPLICATION TO REACTION WHEEL MOMENTUM DUMPING

Abstract

The atm of this thesis is to study, develop and implement an algorithm for the reaction wheel momentum management system. Disturbance Forces affecting the satellite in Low Earth Orbits was analyzed. Reaction wheel selection and stzmg criteria were developed according to this analysis. A generalized model of the attitude dynamics for a 3-axis stabilized satellite was designed, implemented, tested and verified using Simulink. A PD controller

design technique

Model (WMM)

was introduced for preliminary design. The World Magnetic

was implemented using the most recent updated data. A

functional Matlab toolbox was designed and implemented. Several Simulink blocks representing the earth's magnetic field were also built. The magnetic field in Low Earth Orbits was modeled using the WMM, Matlab toolbox and Simulink blocks. These modules were then used to simulate the process of momentum dumping of reaction wheels using the earth's magnetic field. Torqrods were used as actuators to this process. Two Control laws for the magnetic dipole moment estimation were developed and implemented. Performance and efficiency analysis for this process was also gtven.