SINGULARITY AVOIDANCE LAW FOR CMG USING VIRTUAL ACTUATOR

CMGs are actuators for the attitude control of spacecraft. The simplest steering logic of CMGs is the well-known pseudo-inverse method, which is derived from the minimization problem. A drawback of this logic is that the CMG can be singular during the operation. In this paper, the singularity problem is investigated, and a singularity avoidance steering law for CMGs using virtual actuator is proposed. The virtual vector is determined by cross product with 4 column vectors of Jacobian matrix. Using this virtual vector, the system can escape the singular state effectively when CMGs approaches to singular configuration.