Nonzero average current in kicked symmetry and asymmetry nanomechanical shuttles

We studied the average current in kicked nanomechanical shuttles. A kicked ac voltage is applied into the system. This ac voltage consists two parts. One part is normal sine function with frequency ω. The other is pulsed comb like function with frequency ω_k. The ac voltage was applied into both left-right symmetry and asymmetry shuttle systems. For the normal shuttle, the left-right symmetry keep the average current zero. However, for the kicked nanomechanical shuttle, even the system keep the left-right symmetry, it have nonzero average current. This nonzero average current exist in both regular and chaos motion region of shuttles. For asymmetry nanomechanical shuttle system, the frequency and strength of pulsed ac voltage show strong effect on the average current. For some special frequency of pulsed ac voltage, the nonzero average current exist in any tongues. For high frequency and strong pulsed ac voltage, the nanomechanical shuttle system are trained robust from systemic parameters, such as the strength of normal sine function voltage. These effects make the kicked pulsed ac voltage highly useful in the realistic application of nanomechanical shuttles.