Patent ID: 6999862

Claim:
An electric power steering apparatus comprising a motor for generating steering assist power; a sensor for determining steering torque required to operate a steering wheel; and a controller for controlling said motor so as to generate the steering assist power according to the determined steering torque; said electric power steering apparatus further comprising: a determining part for determining a rotation angular velocity correspondence value corresponding to the rotation angular velocity of said steering wheel; a determining part for determining a change velocity correspondence value corresponding to the change velocity of said steering torque; a storing part for storing a first relation set between said rotation angular velocity correspondence value and a first motor output correction value correlating with said rotation angular velocity correspondence value; a storing part for storing a second relation set between said change velocity correspondence value and a second motor output correction value directly correlating with said change velocity correspondence value; and a correcting part for correcting the output of said motor in accordance with the sum of said first motor output correction value corresponding to the determined rotation angular velocity correspondence value and said second motor output correction value corresponding to the determined change velocity correspondence value; wherein, in a frequency response characteristic represented by the steering frequency of said steering wheel and the amplitude ratio of the steering torque relative to the steering angle of said steering wheel, said first relation is set such that the amplitude ratio is within a setting range as a result of correction of the output of said motor, at least within the steering frequency range when a person operates the steering wheel; and in a frequency response characteristic represented by the frequency of the disturbance torque input from the road surface to the steering system via vehicle wheels and the amplitude ratio of the steering torque relative to said disturbance torque, said second relation is set such that the amplitude ratio becomes smaller at the resonance frequency as a result of correction of the output of said motor.