Attitude Control on SU(2): Stability, Robustness, and Similarities

This letter concerns trajectory tracking control of attitude dynamics configured on SU(2). Inspired by a popular geometric tracking controller on SO(3), differential geometric tools are used to derive both continuous and discontinuous attitude controllers on the SU(2) manifold, relating these to preexisting controllers operating with imaginary quaternion errors. Additionally, a robustness result is given for the controllers on SU(2), which is illustrated by simulation examples.