Singularity avoidance of CMGs by virtual actuators

An implementable and practical steering law of control moment gyros (CMGs) to avoid singularity is addressed in this paper. The singularity strategy of CMGs revised in this paper is based on a simple but practical virtual actuator methodology. It is known that in a special case of singularity and torque requirement, the virtual CMGs can provide perfect command torque without torque error, which can be proven analytically. In this paper, much extensive analysis is accomplished to provide the performance of the virtual actuator concept, which can avoid the singular configuration of CMGs with possibly smaller control torque error than the conventional singularity robustness method. Finally, the steering law based on the virtual actuator concept is demonstrated by numerical simulations.