“…For instance, it may be interesting to revisit a Hopf bifurcation of codimension two in delayed systems as it occurs in some robotics applications [28]. Furthermore, the Floquet theory for delay differential equations, and thus the linear stability analysis for a periodic reference state, was already established in [29,30,31]. However, a corresponding synergetic system analysis which derives the order parameter equations and the normal forms for bifurcations of oscillatory solutions is still missing [10,11,32].…”