Patent ID: 8843276

Claim:
A control device of a steering transmission ratio variable device comprising: a motor that is able to apply a driving force that promotes relative rotation between a steering output shaft coupled to wheels to be turned and a steering input shaft that applies a steering input to the steering output shaft to one of either the steering output shaft or the steering input shaft; a motor driving device that drives the motor; a locking device that is able to restrict the relative rotation; a setting device that is configured to prescribe a drive voltage of the motor and set a gain that acts on the motor during a locking control period in which a state of the steering transmission ratio variable device switches from an unlocked state in which the relative rotation is not restricted to a locked state in which the relative rotation is restricted; a determining device that is configured to determine the drive voltage of the motor based on the set gain; a controller that is configured to control the motor driving device so that the determined drive voltage is supplied to the motor, wherein the setting device sets a damping gain, which acts in a direction that reduces the rotating speed of the motor, to a value that is larger than a reference value corresponding to the unlocked state, while the determining device determines the drive voltage of the motor based on the set damping gain.