“…With more rotation degrees of freedom under consideration, up to three for full 3D motion, rotation matrix parametrization has some disadvantages, notably the presence of singularities at certain locations. Many alternative methods have therefore been proposed in the literature for the parametrization of rotations in 3D, some of which include Euler angles and Rodrigues parameters [37], unit quaternions [37,38,39,25,40,41,42,1,43] or a Lie group framework [32,33,44,34,24]. In this paper, we choose to parameterize the rotations in 3D using quaternions, in large part since they naturally lead to polynomial nonlinearities in the model, ideal for applying the ANM.…”