US Patent 7826950 Electric power steering apparatus

In an electric power steering apparatus, steering torque of a steering wheel is detected by a torque sensor, and a motor 10 for generating steering assist power is controlled so that the steering assist power is generated according to a basic assist torque corresponding to the detected steering torque. A correspondence relationship between the steering torque and the basic assist torque is set such that an assist gradient that is a rate of change of the basic assist torque to the steering torque varies according to variation of the steering torque. A correction amount of an output of the motor 10 varies according to the variation of the assist gradient.