Global Steering of Single Gimballed Control Moment Gyroscopes Using a Directed Search

A guided depth-first search that manages null motion about torque-producing trajectories calculated with a singularity-robust inverse is proposed as a practical feedforward steering law that can globally avoid (or minimize the impact of) singular states in minimally-redundant systems of single gimballed control moment gyroscopes. Cost and heuristic functions are defined to guide the search procedure in improving gimbal trajectories. On-orbit implementation of the steering law is proposed as an extension to momentum management algorithms. A set of simulation examples is presented, illustrating the search performance for a minimally-redundant, pyramid-mounted array. Sensitivities of feedforward gimbal trajectories are examined in the presence of unmodelled disturbances, and techniques are proposed for avoiding excessive divergence.