Quantization of the average velocity of motion in a periodic potential under the action of an ultrasonic perturbation

The motion of a body in a periodic potential relief with weak damping is co nsidered. It is shown that, in the presence of an additional periodic exter nal action, dependence of the period-average velocity on the mean force of friction exhibits plateaus where variations in the acting force do not lead to changes in the average velocity. The plateau velocity is proportional t o the frequency of the applied periodic perturbation and can be readily con trolled. The effect can be used to create the driving mechanisms capable of ensuring motion at a strictly preset velocity not affected by the applied load variations. (C) 2001 MAIK "Nauka/Interperiodica".