Singularity Avoidance Algorithms for Spacecraft Attitude Control using Single Gimbal Control Moment Gyroscopes

Abstract

Single gimbal control moment gyroscopes are attractive actuators for spacecraft attitude control systems. However, intrinsic kinematic singularities preclude torque generation along certain directions and lead to loss of three-axis control of the spacecraft. Kinematic singularities also exist in robotic manipulator systems which are mechanical analogs of the single gimbal control moment gyroscope systems. In robotic manipulator systems, kinematic singularities preclude end-effector motions in singular directions. An algorithm is proposed to avoid singularities in control moment gyroscope systems. The proposed algorithm is based on the extended Jacobian, used to solve singularity avoidance problem in the robotic manipulator system, and the null motion avoidance algorithms. The current algorithm has been shown to avoid internal kinematic singularities when applied to spacecraft maneuver problems. Feedback torque requests are generated using control laws based on the Liapunov's stability theory.