  Wearless friction is investigated in a simple mechanical model called
Frenkel-Kontorova-Tomlinson model. We have introduced this model in [Phys. Rev.
B, Vol. 53, 7539 (1996)] where the static friction has already been considered.
Here the model is treated for constant sliding speed. The kinetic friction is
calculated numerically as well as analytically. As a function of the sliding
velocity it shows many structures which can be understood by varies kinds of
phonon resonances (normal, superharmonic and parametric) caused by the
so-called "washboard wave". For increasing interaction strength the regular
motion becomes chaotic (fluid-sliding state). The fluid sliding state is mainly
determined by the density of decay channels of m washboard waves into n
phonons. We also find strong bistabilities and coherent motions with
superimposed dark envelope solitons which interact nondestructively.
