SIMPLIFIED SINGULARITY AVOIDANCE USING VARIABLE SPEED CONTROL MOMENT GYROSCOPE NULL MOTION

Singularity avoidance in Variable Speed Control Moment Gyroscope (VSCMG) systems can require significant computation to determine null motion steering commands. This paper presents a less complicated method of determining appropriate null motion steering laws while achieving similar performance as current, more complicated, methods. This method is based on tracking the range of the transverse axes, instead of the rank of the VSCMG steering control projection matrix. The new approach does not require any knowledge of the rotor speeds in order to create singularity avoidance null motion steering commands. The performance using this simpler CMG singularity cost function is essentially identical to previously published methods, as is illustrated with a simple numerical simulation. The main benefit of this new method for CMG singularity avoidance using VSCMG devices is that the null motion commands are greatly simplified compared to previous methods.