  This paper investigates the robust global attitude stabilization problem for
a rigid-body system using quaternion-based feedback. We propose a novel
synergistic hybrid feedback with the following notable features: (1) It
demonstrates central synergism by utilizing a minimal number of potential
functions; (2) It ensures consistency with respect to the unit quaternion
representation of rigid-body attitude; (3) Its state-feedback laws incorporate
a shared action term that steers the system toward the desired attitude. We
demonstrate that the proposed hybrid feedback method effectively solves the
problem at hand and guarantees robust uniform global asymptotic stability.
