  Over recent years, a lot of progress has been achieved in understanding of
the relationship between localization and transport of energy in essentially
nonlinear oscillatory systems. In this paper we are going to demonstrate that
the structure of the resonance manifold can be conveniently described in terms
of canonical action-angle variables. Such formalism has important theoretical
advantages: all resonance manifolds may be described at the same level of
complexity, appearance of additional conservation laws on these manifolds is
easily proven both in autonomous and non-autonomous settings. The harmonic
balance - based complexification approach, used in many previous studies on the
subject, is shown to be a particular case of the canonical formalism. Moreover,
application of the canonic averaging allows treatment of much broader variety
of dynamical models. As an example, energy exchanges in systems of coupled
trigonometrical and vibro-impact oscillators are considered.
