Thesis Type: Post Graduate
Institution Of The Thesis: Orta Doğu Teknik Üniversitesi, Faculty of Engineering, Department of Aerospace Engineering, Turkey
Approval Date: 2007
Student: ÖZGÜR KAHRAMAN
Consultant: OZAN TEKİNALPAbstract:
In this thesis, attitude control of small satellites with dissimilar actuator is studied and the effects of control allocation methods on maneuvering are examined in detail. Magnetorquers and reaction wheels are considered as the actuators of a modeled remote sensing -nadir pointing- small satellite. Matlab® Simulink simulation models are developed to model the satellite dynamics and the actuators on the satellite. The simulations are based on conceptual RASAT satellite, and, for verification, orbit data is taken from BILSAT satellite that is operated by TUBITAK Space Research Institute. Basic satellite control modes are developed and tested to obtain nominal control. Actuator failures are analyzed for different possible cases. A control allocation method called Blended Inverse that was originally proposed for steering CMGs is applied to select the actuators to avoid actuator saturation and singularity transition. The performance of traditional pseudo inverse method is compared with the blended inverse method and simulation results are given and discussed. The superiority of blended inverse over pseudo inverse is demonstrated.