Hybrid Steering Logic for Single-Gimbal Control Moment Gyroscopes

The development of a hybrid steering logic that maintains attitude tracking precision while avoiding hyperbolic internal singularities or escaping elliptic singularities inherent to single-gimbal control moment gyroscopes is discussed. The hybrid steering logic enables null motion and limits torque error when approaching a hyperbolic internal singularity, or it adds torque error and limits null motion when approaching an elliptic internal or external singularity. The hybrid-steering-logic algorithm accomplishes these tasks through the definitions of novel singularity metrics that transition continuously from local-gradient to pseudoinverse methods when moving from hyperbolic to elliptic singularities. Analysis and simulations are presented to demonstrate the performance of the hybrid steering logic as compared with the two legacy methods. The development and results are applied to a four-single-gimbal-control-moment-gyroscope pyramid arrangement with a skew angle of θ = 54.74 deg.