Patent attributes
An apparatus includes a steering assist torque determination unit and a steering assist torque control unit. The steering assist torque determination unit determines a steering assist torque including a first component that is determined on the basis of a deviation between an actual steering angle and a target steering angle for achieving a target path determined irrespective of driver's steering. The steering assist torque control unit controls a steering assist mechanism such that the steering assist torque is applied. The ratio of the magnitude of the first component of the steering assist torque to the deviation between the target steering angle and the actual steering angle is determined on the basis of the magnitude of the deviation between the steering assist torque and the driver's steering torque in a past predetermined period.