Lane tracking control system for vehicle

• US 6,748,302 B2
• Filed: 01/11/2002
• Issued: 06/08/2004
• Est. Priority Date: 01/18/2001
• Status: Expired due to Term

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Kawazoe, Hiroshi
• Primary Examiner(s): Camby, Richard M.
• Application Number:
  US10/042,225
• Publication Number:
  US 20020095246A1
• Time in Patent Office: 879 Days
• Field of Search: 701/1, 701/28, 701/23, 701/44, 701/27, 701/41, 701/300, 701/301, 348/113, 348/118, 348/119, 382/148, 340/905, 340/995, 340/904, 340/937
• US Class Current: 701/1
• CPC Class Codes: B60T 2201/08 Lane monitoring; Lane Keeping Systems
• CPC Class Codes: B60T 2201/087 using active steering actuation
• CPC Class Codes: B62D 15/025 Active steering aids, e.g. helping the driver by actively influencing the steering system after environment evaluation B62D1/28 takes precedence
• CPC Class Codes: G05D 1/0246 using a video camera in combination with image processing means

Abstract

A lane tracking control system for a vehicle includes a controller which is coupled to a road image detector for taking a view ahead of the vehicle, a vehicle behavior detector for detecting a behavior of the vehicle and a steering control mechanism for executing a steering control in response to a steering control signal. The controller is arrange to calculate a road shape on the basis of the view taken by the road image detector, to determine on the basis of the road shape and the vehicle behavior detected by the vehicle behavior detector whether the vehicle tends to depart from a lane traveled by the vehicle, and to output the steering control signal to the steering control mechanism so as to control the vehicle behavior at a desired behavior when the vehicle tends to depart from the lane.

Claims

1. A lane tracking control system for a vehicle, comprising:

a road image detector taking a view ahead of the vehicle;

a vehicle behavior detector detecting a behavior of the vehicle;

a steering control mechanism executing a steering control in response to a steering control signal; and

a controller coupled to the road image sensor, the vehicle behavior detector and the steering control mechanism, the controller being arranged,

to calculate a road shape on the basis of the view taken by the road image detector,

to determine whether the vehicle tends to depart from a lane traveled by the vehicle, on the basis of the road shape and the vehicle behavior detected by the vehicle behavior detector,

to output the steering control signal to the steering control mechanism to control the vehicle behavior at a desired behavior when the vehicle tends to depart from the lane,

wherein the vehicle behavior detector comprises a steering torque sensor, a turn signal lamp, a vehicle speed sensor and a yaw rate sensor.

2. The lane tracking control system as claimed in claim 1, wherein the controller outputs the steering control signal to the steering control mechanism so that a vehicle traveling locus calculated from the vehicle behavior gradually approaches the road shape when the vehicle tends to depart from the lane.

3. The lane tracking control system as claimed in claim 1, wherein the controller outputs the steering control signal to the steering control mechanism so as to increase a lane departure time period between a first moment of determining that the vehicle tends to depart from the lane and a second moment of a real lane departure of the vehicle when the vehicle tends to depart from the lane.

4. The lane tracking control system as claimed in claim 1, wherein the controller outputs the steering control signal to the steering control mechanism so that a steering control parameter employed for controlling the steering control mechanism is gradually varied.

5. The lane tracking control system as claimed in claim 3, wherein the controller determines a lane departure point, at which the vehicle departs from the lane, so that the lane departure time period takes a constant value.

6. The lane tracking control system as claimed in claim 1, wherein the road image detector comprises a camera which takes a view ahead of the vehicle and an image processor which processes the view into lane-marker indicative information, and the controller calculates a curvature of the lane of the road ahead of the vehicle from the lane-marker indicative information.

7. The lane tracking control system as claimed in claim 4, further comprising a vehicle speed detector for detecting a speed of the vehicle, the controller calculating a gain which increases according to an increase of the speed of the vehicle, and calculates the steering control parameter by multiplying a target turn degree of the vehicle by the gain.

8. The lane tracking control system as claimed in claim 2, further comprising a vehicle speed detector for detecting a speed of the vehicle, the controller outputs the steering control signal to the steering control mechanism so that a curvature of the vehicle traveling locus is increased according to the increase of the speed of the vehicle.

9. The lane tracking control system as claimed in claim 3, wherein the controller outputs the steering control signal to the steering control mechanism so that a curvature of a vehicle traveling locus calculated from the vehicle behavior is decreased after the curvature of the vehicle traveling locus reaches a target curvature.

10. The lane tracking control system as claimed in claim 2, wherein the controller outputs the steering control signal to the steering control mechanism so that the curvature of the vehicle traveling locus is gradually decreased after a predetermined time elapsed from a moment that the curvature of the vehicle traveling locus corresponds to a curvature of the lane.

11. A lane tracking control system for a vehicle, comprising:

a road image detector taking a view ahead of the vehicle;

a vehicle behavior detector detecting a behavior of the vehicle;

a steering control mechanism executing a steering control in response to a steering control signal; and

a controller coupled to the road image sensor, the vehicle behavior detector and the steering control mechanism, the controller being arranged,

to calculate a road shape on the basis of the view taken by the road image detector,

to determine whether the vehicle tends to depart from a lane traveled by the vehicle, on the basis of the road shape and the vehicle behavior detected by the vehicle behavior detector,

to output the steering control signal to the steering control mechanism to control the vehicle behavior at a desired behavior when the vehicle tends to depart from the lane,

wherein the vehicle behavior detector comprises a steering angle detector for detecting a steering angle of the vehicle, a yaw angle detector for detecting a yaw angle of the vehicle and a lateral displacement detector for detecting a lateral displacement of the vehicle relative to a center of the lane.

12. The lane tracking control system as claimed in claim 11, wherein the controller outputs the steering control signal to the steering control mechanism so that a vehicle traveling locus calculated from the vehicle behavior gradually approaches the road shape when the vehicle tends to depart from the lane.

13. The lane tracking control system as claimed in claim 11, wherein the controller outputs the steering control signal to the steering control mechanism so as to increase a lane departure time period between a first moment of determining that the vehicle tends to depart from the lane and a second moment of a real lane departure of the vehicle when the vehicle tends to depart from the lane.

14. The lane tracking control system as claimed in claim 11, wherein the controller outputs the steering control signal to the steering control mechanism so that a steering control parameter employed for controlling the steering control mechanism is gradually varied.

15. The lane tracking control system as claimed in claim 13, wherein the controller determines a lane departure point, at which the vehicle departs from the lane, so that the lane departure time period takes a constant value.

16. The lane tracking control system as claimed in claim 11, wherein the road image detector comprises a camera which takes a view ahead of the vehicle and an image processor which processes the view into lane-marker indicative information, and the controller calculates a curvature of the lane of the road ahead of the vehicle from the lane-marker indicative information.

17. The lane tracking control system as claimed in claim 11, further comprising a vehicle speed detector for detecting a speed of the vehicle, the controller calculating a gain which increases according to an increase of the speed of the vehicle, and calculates the steering control parameter by multiplying a target turn degree of the vehicle by the gain.

18. The lane tracking control system as claimed in claim 11, further comprising a vehicle speed detector for detecting a speed of the vehicle, the controller outputs the steering control signal to the steering control mechanism so that a curvature of the vehicle traveling locus is increased according to the increase of the speed of the vehicle.

19. The lane tracking control system as claimed in claim 13, wherein the controller outputs the steering control signal to the steering control mechanism so that a curvature of a vehicle traveling locus calculated from the vehicle behavior is decreased after the curvature of the vehicle traveling locus reaches a target curvature.

20. A lane tracking control system for a vehicle, comprising:

road shape detecting means for detecting a shape of a road ahead of the vehicle;

turn degree detecting means for detecting a degree of a turn of the vehicle;

lane departure determining means for determining whether the vehicle tends to depart from a lane of the road ahead of the vehicle; and

steering control means for executing a steering control of the vehicle so as to elongate a lane departure time period between a first moment of determining that the vehicle tends to depart from the lane and a second moment of a real lane departure of the vehicle.