LAUSR

This correspondence investigates the underactuated spacecraft attitude maneuver problem using two parallel single-gimbal control moment gyros (SGCMGs). According to the configuration of the SGCMGs, the principle axes of the spacecraft are divided into two parts, namely, the axes with and without direct control input. Based on this division, a two-level control strategy, a low-level tracking control part to track the desired angular velocity error about the axes with direct control input and a high-level sliding mode control part to stabilize the angular velocity error, is developed. Four numerical scenarios are conducted to verify the proposed control logic. Simulation results show that the target attitude is a global equilibrium and any attitude can be reached when the whole system is feasible. If the controllability is not satisfied, the spacecraft rotates in the adjacent region around the desired attitude.