APPARATUS FOR CONTROLLING STEERING ANGLE, LANE KEEPING ASSIST SYSTEM HAVING THE SAME AND METHOD THEREOF

An apparatus for controlling a steering angle, a system including the same, and a method thereof are provided may include a steering angle gain variation determination device that determines an increase or a decrease of a steering angle gain variation rate depending on a steering angle error value, a steering angle gain determination device that determines a steering angle gain based on the steering angle gain variation rate, a steering angle gain regulation device that determines a final gain by reflecting a driver intention in a steering angle gain, and a steering torque determination device that determines steering torque by use of the final gain.