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

Patent metadata

Field	Value
Publication number	US-9517795-B2
Application number	US-201514942432-A
Country	US
Kind code	B2
Filing date	Nov 16, 2015
Priority date	Nov 19, 2014
Publication date	Dec 13, 2016
Grant date	Dec 13, 2016

Abstract

A lane keeping assist system, including: a first calculation unit which calculates left and right position errors of a front portion of the vehicle, a curvature of a lane of the front portion, and a head angle formed based on the lane from a front image of the vehicle captured by an image sensor, and calculates a target yaw rate using the left and right position errors, the curvature of the lane, and the head angle formed based on the lane which are calculated; a second calculation unit which calculates a steering torque control value for driving the calculated target yaw rate using vehicle condition information including front and rear yaw rates of the vehicle sensed by a yaw rate sensor, and a steering angle and a speed of the vehicle; and a steering driving unit which controls steering of the vehicle for keeping a lane.

First claim

What is claimed is:

1. 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 first calculation unit configured to calculate 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 front image of the vehicle, and calculate 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;
a second calculation unit configured to calculate 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 calculate 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
a steering driving unit configured to determine 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 control steering of the vehicle for lane keeping using the final steering torque control value.

2. The LKAS of claim 1 , wherein the steering driving unit determines a greater value between the steering torque control value of the front portion of the vehicle calculated in the first calculation unit and the steering torque control value of the rear portion of the vehicle calculated in the second calculation unit as the final steering torque control value.

3. The LKAS of claim 1 , wherein the steering driving unit calculates an average value of the steering torque control value of the front portion of the vehicle calculated in the first calculation unit and the steering torque control value of the rear portion of the vehicle calculated in the second calculation unit, and determines the calculated average value as the final steering torque control value of the vehicle.

4. The LKAS of claim 1 , wherein the second calculation unit calculates the left and right position errors and the curvature of the lane of the rear portion of the vehicle using the following equations,
e 21= e 11− L 1*sin ψ

e 22= e 12− L 1*sin ψ

wherein e21 and e22 represent the left and right position errors of the rear portion of the vehicle, e11 and e12 represent the left and right position errors of the front portion of the vehicle, ψ represents the head angle formed based on the lane, and L1 represents a distance which is from one position of the front portion of the vehicle in which an image sensor is installed to another position which is one position of the rear portion of the vehicle.

5. The LKAS of claim 1 , wherein the second calculation unit calculates the left and right position errors and the curvature of the lane of the rear portion of the vehicle using the following equations,
e 21= e 11− L 2*sin ψ

e 22= e 12− L 2*sin ψ

wherein e21 and e22 represent the left and right position errors of the rear portion of the vehicle, e11 and e12 represent the left and right position errors of the front portion of the vehicle, ψ represents the head angle formed based on the lane, and L2 represents a distance which is from one position of the front portion of the vehicle in which an image sensor is installed to another position which is one position located in the rear portion of the vehicle.

6. The LKAS of claim 1 , wherein the second calculation unit determines the curvature of the lane calculated at a position ahead of a distance between one position of the front portion of the vehicle and one position of the rear portion of the vehicle considering the vehicle speed as the curvature of the lane of the rear portion of the vehicle.

7. 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.

8. The LKAS of claim 7 , wherein the first calculation unit generates a target trajectory using the left and right position errors of the front portion of the vehicle, the curvature of the lane, and the head angle formed based on the lane, and calculates the target yaw rate for tracking the target trajectory.

9. The LKAS of claim 7 , further comprising:
a steering angle sensor installed in a handle of the vehicle for sensing the steering angle of the vehicle.

10. The LKAS of claim 7 , wherein the second calculation unit calculates the steering torque control value using an average value of the front yaw rate and the rear yaw rate, and provides the calculated steering torque control value to the steering driving unit.

11. The LKAS of claim 7 , wherein the second calculation unit calculates the steering torque control value using a greater value between the front yaw rate and the rear yaw rate, and provides the calculated steering torque control value to the steering driving unit.

12. 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

Assignees

• Hyundai Mobis Co Ltd

Inventors

• You Eun Young
• Lee Kyu Hoon

Classifications

• B62D15/025 Primary

  Active steering aids, e.g. helping the driver by actively influencing the steering system after environment evaluation (B62D1/28 takes precedence) · CPC title

• B60R2300/804

  for lane monitoring · CPC title

• B60R1/00

  Optical viewing arrangements; Real-time viewing arrangements for drivers or passengers using optical image capturing systems, e.g. cameras or video systems specially adapted for use in or on vehicles · CPC title

• B60W30/12 Primary

  Lane keeping · CPC title

• B62D6/003

  in order to control vehicle yaw movement, i.e. around a vertical axis (B62D6/007 takes precedence) · CPC title