Attitude Control with Momentum Exchange Devices

This course is part 1 of the specialization Advanced Spacecraft Dynamics and Control. It is a direct continuation of the Coursera specialization Spacecraft Dynamics and Control. This first course focuses on nonlinear attitude feedback control using a range of angular momentum devices. The course provides a comprehensive review of prerequisite material. Next it develops equations of motion of a spacecraft with momentum exchange devices such as reaction wheels (RWs), control momentum gyroscopes (CMGs) and variable speed control moment gyroscopes (VSCMGs). The course discusses developing a complex spacecraft simulation with a number VSCMGs and how to approach debugging such complex software. The use of the work/energy theorem is discussed to assist with debugging the simulation by validating angular momentum, energy, changes in momentum and mechanical power. Further, the use of null motion is explored to reconfigure the attitude control devices to avoid singularities and gimbal lock. The redundancy is exploited to seek control solutions that avoid classical CMG singularities.

• Revisiting Basics of Spacecraft Kinematics
• The prerequisite topics of spacecraft kinematics are reviewed in this module. This sequence is intended to ramp up the student on the mathematical tools and concepts required for this course. For each topic we also dig a little deeper into the subject matter.
• Revisiting Basics of Spacecraft Kinetics
• Review of fundamental properties of a closed dynamical system leading to the development of the equations of motion.
• Revisiting the Basics of Nonlinear Spacecraft Control
• Review of the fundamental nonlinear stability definitions, using Lyapunov's direct method, as well as discussing stability proof modifications if the system is time dependent.
• VSCMG Dynamics
• Develop the kinematics and kinetics of the variable speed CMG devices.
• Momentum Based 3-Axis Attitude Control
• Learn how to achieve 3-axis attitude feedback control using a series of momentum exchange devices such as reaction wheels, control moment gyroscopes (CMGs) and variable speed CMGs