Lane keeping assist system of vehicle and method of controlling the same

A lane keeping assist system (LKAS), comprising:

• an image sensor configured to capture a front of a vehicle, and obtain a front image of the vehicle;
• a yaw rate sensor located in a front portion and a rear portion of the vehicle, and configured to sense a front yaw rate and a rear yaw rate of the vehicle;
• a first calculation unit configured to calculate left and right position errors of the front portion of the vehicle, a curvature of a lane of the front portion of the vehicle, and a head angle formed based on the lane from the front image of the vehicle, and calculate a target yaw rate using the left and right position errors of the front portion of the vehicle, the curvature of the lane of the front portion of the vehicle, and the head angle formed based on the lane which are calculated;
• a second calculation unit configured to calculate a steering torque control value for driving the calculated target yaw rate using vehicle condition information including the front and rear yaw rates of the vehicle, and a steering angle and a speed of the vehicle;
• and
• a steering driving unit configured to control steering of the vehicle for keeping a lane using the calculated steering torque control value.

A lane keeping assist method, comprising:

• capturing a front of a vehicle, and obtaining a front image of the vehicle;
• calculating left and right position errors of a front portion of the vehicle, a curvature of a lane of the front portion of the vehicle, and a head angle formed based on the lane from the obtained front image of the vehicle, and calculating a steering torque control value of the front portion of the vehicle using the left and right position errors of the front portion of the vehicle, the curvature of the lane of the front portion of the vehicle, the head angle formed based on the lane, which are calculated, and a vehicle speed;
• calculating left and right position errors of a rear portion of the vehicle, and a curvature of a lane of the rear portion of the vehicle, and calculating a steering torque control value of the rear portion of the vehicle using the left and right position errors of the rear portion of the vehicle, the curvature of the lane of the rear portion of the vehicle, the head angle formed based on the lane, which are calculated, and the vehicle speed;
• and
• determining a final steering torque control value of the vehicle using the steering torque control value of the front portion of the vehicle and the steering torque control value of the rear portion of the vehicle which are calculated, and controlling steering of the vehicle for lane keeping using the final steering torque control value.