Study on Failure Analysis and Improved Constrained Steering Law Design for SGCMGs

摘要

Failure of Single Gimbal Control Moment Gyro(SGCMG)is investigated. For the Five Pyramid Configuration(FPC)with two gyros in failure state,the degraded system can be reconfigured as a Deformed Pyramid Configuration (DPC). The dynamic equation and the singular angular momentum equation of the degraded system are established. And both passable and impassable singular angular momentum hypersurfaces of the original and the degraded systems are plotted. Through singular surfaces, the difference between FPC and DPC in singularity distinctness and angular momentum envelopes is obtained directly. Finally, the constrained steering law for the standard Pyramid Configuration (PC) is improved. The Improved Constrained Steering Law(IC)is applied to the degraded system. The simulation results demonstrate that IC steering law has advantages over other usual steering laws in simplicity,singularity avoidance and exactness of output torque. Also the IC steering law endows the degraded system with fine controllability in a restricted angular momentum workspace.