  We perform extended numerical simulation of the dynamics of dry friction,
based on a model derived from the phenomenological description proposed by T.
Baumberger et al.. In the case of small deviation from the steady sliding
motion, the model is shown to be equivalent to the state- and rate-dependent
friction law which was first introduced by Rice and Ruina on the basis of
experiments on rocks. We obtain the dynamical phase diagram that agrees well
with the experimental results on the paper-on-paper systems. In particular, the
bifurcation between stick-slip and steady sliding are shown to change from a
direct (supercritical) Hopf type to an inverted (subcritical) one as the
driving velocity increases, in agreement with the experiments.
