  This paper deals with an advanced modeling of the feed drives of a five axis
machine tool within the context of High Speed Machining. The management of the
multi axes as well as high velocities causes problems to the set machine tool -
Numerical Controller throughout the trajectory execution process. As a result,
many errors are introduced during machining all process long affecting the
surface quality. The paper aims at modeling the feed drive dynamics during
trajectory follow-up including the current, the velocity and position loops as
well as the feed forward terms, which characterize classical drives on actual
HSM machines. It concerns translational axes as well as rotary axes. A
procedure of identification is implemented. Performances of the model are
assessed by the comparison between simulated tool paths to the real one.
Experimental verifications of the virtual axis model are detailed for three and
five axis trajectories presenting various types of geometrical discontinuities.
