Inertial Brownian motors driven by biharmonic signals

We study transport properties of an inertial Brownian particle moving in symmetric periodic structures and driven by the external time-periodic signal of two harmonic components: sin(ωt)+εsin(2ωt+ϕ). We analyze the influence of symmetric, antisymmetric and asymmetric signals on directed transport and reveal the shift symmetry of the stationary averaged velocity v of the Brownian particle with respect to the relative phase ϕ of two components of the signal. The magnitude and sign of the stationary averaged velocity v has complex structure in the parameter space. Typically, the multiple velocity reversals occur when the system parameters are changed.