SPACECRAFT ATTITUDE CONTROL USING SINGLE GIMBAL CONTROL MOMENT GYROSCOPES

Abstract

The spacecraft attitude control problem using the single gimbal control moment gyroscopes (SGCMGs) is investigated. The inherent singularity problem lying in the SGCMG-system is analyzed and visualized and a general fault-model of the SGCMG is established. Based on the established fault model, an effectiveness matrix incorporated singularity index was introduced to describe the status of the SGCMG cluster, and angular velocity constrained tracking control was completed when the SGCMG suffers from fault, system uncertainties and external disturbances. For an extreme condition when some of the SGCMGs fail completely and 3-axis controllability is lost, the two-SGCMG actuate stabilization and maneuver was completed when the controllability condition is satisfied. If the angular momentum is such that stabilization or maneuver to the equilibrium is not possible, the system will be governed to suitably safe and conservative periodic oscillations about the equilibrium.