WE CLAIM:
1. An electric power steering system configured to drive
a motor based on an assist map in which a current command
value in accordance with steering torque and a vehicle
speed is defined and configured to perform assist control
on a steering system of a vehicle, the electric power
steering system comprising:
a current command value calculating unit configured to output a current command value in accordance with the steering torque and the vehicle speed, based on the assist map, wherein
the current command value calculating unit includes a vibration component reducing section configured to reduce a vibration component resulting from vibrations for warning that have been transmitted to a steering wheel, the vibration component being included in the steering torque.
2. The electric power steering system according to claim
1, wherein the current command value calculating unit
multiplies a difference value between the steering torque
and output from the vibration component reducing section by
a predetermined gain factor, and adds a resultant value to
the current command value.
3. The electric power steering system according to claim
2, wherein the current command value calculating unit
further includes a gain factor calculating section
configured to generate the gain factor in accordance with
an absolute value of a torque signal, the torque signal
being an output from the vibration component reducing
section.
4. The electric power steering system according to claim

3, wherein the gain factor calculating section generates the gain factor that is proportional to the absolute value of the torque signal.
5. The electric power steering system according to claim 3, wherein the gain factor calculating section generates the gain factor that approximates an amount of change in the assist map in accordance with the absolute value of the torque signal.
6. The electric power steering system according to any one of claims 1 to 5, wherein the vibration component reducing section is a primary low-pass filter, a secondary low-pass filter, a notch filter, or a low-pass type notch filter.