Singularity analysis and steering law design of IPACS with VSCMGs

This paper deals with the singularity problem and steering law design of integrated power/attitude control system (IPACS) with variable-speed control moment gyros (VSCMGs). Two singularity concepts, i.e., CMG singularity and IPACS singularity are proposed. For a given CMG singular direction, the saturate speeds of VSCMGs rotors along with the direction are calculated via optimization theory. Furthermore, the necessary and sufficient conditions and the corresponding proof for a IPACS suffering from singularity are achieved. The singularity of an actual IPACS affected by the angular velocity of spacecraft is analyzed. In order to realize reasonable momentum management, the steering law with weighting matrices is designed. An example is given to validate the effectiveness of the IPACS singularity criterion, also the numerical simulation results show that the steering law is effectual and has well momentum management characteristics.