Date of Defense
22-11-2024 10:00 AM
Location
F1-1043
Document Type
Thesis Defense
Degree Name
Master of Science in Mechanical Engineering (MSME)
College
College of Engineering
Department
Mechanical Engineering
First Advisor
Dr. Mohamed Okasha
Keywords
Attitude Control System (ACS), CubeSat, Detumbling, Disturbance Analysis, LQR Controller, PID Controller
Abstract
This thesis presents the design and simulation of the Attitude Control System (ACS) for the GNSSaS 6U CubeSat, developed by the National Space Science and Technology Center (NSSTC) at UAE University. The CubeSat's mission is to enhance GNSS signal accuracy, which requires precise attitude control to achieve this objective. The ACS utilizes magnetorquers and reaction wheels for actuation. The primary objective of this thesis is to design an ACS that fulfills the mission’s performance requirements, including maintaining pointing accuracy in both fine and medium pointing modes. To achieve this, a comprehensive disturbance analysis was conducted, leading to the selection of suitable actuators and control strategies. The ACS implements both PID and LQR controllers to achieve stable and accurate pointing in different operational modes. The ACS was modeled and simulated using MATLAB, focusing on various operational modes, including detumbling, medium pointing, and fine pointing, with sub-modes such as nadir pointing, sun pointing, and ground station tracking. The simulation results demonstrate that the GNSSaS CubeSat achieves stable control and meets its pointing accuracy requirements. The LQR controller proved particularly effective in fine pointing mode, enabling precise and stable transitions between sub-modes by balancing precision and energy consumption. Furthermore, LQR's tuning flexibility allowed for smoother and more stable responses, with minimal oscillation. This work contributes to the development of robust ACS designs for CubeSats, addressing key challenges such as managing external disturbances and ensuring reliable control through effective momentum management. The findings confirm that the GNSSaS ACS meets all mission requirements and lays a solid foundation for future CubeSat missions.
Included in
DESIGN AND IMPLEMENTATION OF ATTITUDE CONTROL SYSTEM FOR GNSSAS 6U CUBESAT
F1-1043
This thesis presents the design and simulation of the Attitude Control System (ACS) for the GNSSaS 6U CubeSat, developed by the National Space Science and Technology Center (NSSTC) at UAE University. The CubeSat's mission is to enhance GNSS signal accuracy, which requires precise attitude control to achieve this objective. The ACS utilizes magnetorquers and reaction wheels for actuation. The primary objective of this thesis is to design an ACS that fulfills the mission’s performance requirements, including maintaining pointing accuracy in both fine and medium pointing modes. To achieve this, a comprehensive disturbance analysis was conducted, leading to the selection of suitable actuators and control strategies. The ACS implements both PID and LQR controllers to achieve stable and accurate pointing in different operational modes. The ACS was modeled and simulated using MATLAB, focusing on various operational modes, including detumbling, medium pointing, and fine pointing, with sub-modes such as nadir pointing, sun pointing, and ground station tracking. The simulation results demonstrate that the GNSSaS CubeSat achieves stable control and meets its pointing accuracy requirements. The LQR controller proved particularly effective in fine pointing mode, enabling precise and stable transitions between sub-modes by balancing precision and energy consumption. Furthermore, LQR's tuning flexibility allowed for smoother and more stable responses, with minimal oscillation. This work contributes to the development of robust ACS designs for CubeSats, addressing key challenges such as managing external disturbances and ensuring reliable control through effective momentum management. The findings confirm that the GNSSaS ACS meets all mission requirements and lays a solid foundation for future CubeSat missions.