sf of the steering system is applied the unit of the frictional characteristics sf of the steering system and the friction compensation torque tf is nm the tuning map is designed in advance in consideration of several factors such as specifications of the vehicle and the steering system such that the tuning map determines the required optimal friction compensation torque tf on the basis of the frictional characteristics sf and the steering reaction force sr of the steering system which are continuously changed when substantially implementing the steering return function further the velocity gain vg is provided to implement the optimal steering return considering the region of velocity generally divides the velocity of 5 km h u02dc 30 km h into a plurality of velocity regions which is determined in consideration of the specifications of the vehicle and the steering system as described above the steering torque t is provided with u2212 steering torque signs ts the hand covered condition s of the steering wheel is applied to the t g set in 0 u02dc 1 the friction compensation torque tf is applied to the tuning map considering the steering reaction force sr with the frictional characteristics sf of the steering system and the velocity v of about 5 km h u02dc about 30 km h is applied to the velocity gain divided into the velocity gain vg.