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. The material covered is taking from the book "Analytical Mechanics of Space Systems" available at https://arc.aiaa.org/doi/book/10.2514/4.105210.