  The quantitative characterization of amplitudes and periods of perturbations
in orbital elements can help to our understanding the minor bodies dynamics,
especially in case motion in vicinity of resonances. The main goal of this
study is to present the new way of the orbital elements approximation by the
results of numerical integration. We develop the approximation of orbital
elements of the small body by the perturbations with combinational frequencies.
We use a criterion of minimum of the standard error in our approximation. In
result we give the approximation of orbital elements for the selected members
of the Hilda group in the 3:2 mean motion resonance with Jupiter.
