Lane-keep assisting system for vehicle

• US 20020041229A1
• Filed: 09/06/2001
• Published: 04/11/2002
• Est. Priority Date: 09/06/2000
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Kawazoe, Hiroshi, Mouri, Hiroshi, Shimakage, Masayasu, Satoh, Shigeki, Sadano, On
• Granted Patent: US 6,489,887 B2
• Time in Patent Office: Days
• US Class Current: 340/438
• CPC Class Codes: B60T 2201/08 Lane monitoring; Lane Keeping Systems
• CPC Class Codes: B60T 2201/083 using active brake actuation
• CPC Class Codes: B60T 2201/089 using optical detection
• CPC Class Codes: G05D 1/0246 using a video camera in combination with image processing means

Abstract

A system for assisting a lane-keep traveling of a vehicle is comprised of a camera for detecting a view ahead of the vehicle, a vehicle behavior detector including a vehicle speed sensor and a yaw rate sensor, and a controller. The controller is arranged to estimate a road shape on the basis of lane markers detected by the camera, to detect a target yaw rate necessary to return the vehicle at a center of the lane markers, and to determine that there is a possibility that the vehicle deviates from the lane when a difference between the target yaw rate and an actual yaw rate detected by the yaw rate sensor becomes greater than a threshold.

Claims

1. A system for assisting a lane-keep traveling of a vehicle, comprising:

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

a vehicle behavior detector detecting a behavior of the vehicle; and

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

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

to calculate a target turn indicative value indicative of a target turn for reaching the vehicle to a target position, on the basis of the road shape detected,

to calculate an actual turn indicative value indicative of an actual turn of the vehicle, and

to determine whether the vehicle approaches a lane boundary of a traveling lane, on the basis of the target turn indicative value and the actual turn indicative value.

2. The system as claimed in claim 1, wherein the controller determines that the vehicle approaches the lane boundary when a difference between the target turn indicative value and the actual turn indicative value is greater than a threshold.

3. The system as claimed in claim 1, wherein the road image detector includes a camera that takes a picture image showing a view ahead of the vehicle, and an image processor that processes the picture image in order to detect lane markers corresponding to the lane boundaries of the traveling lane.

4. The system as claimed in claim 3, wherein the controller determines the target turn indicative value on the basis of an offset quantity between a direction of the target position and a direction of the camera directed ahead of the vehicle.

5. The system as claimed in claim 2, wherein the vehicle behavior detector includes a vehicle speed detector that detects a speed of the vehicle, and the threshold is decreased as the speed of the vehicle is increased.

6. The system as claimed in claim 1, wherein the target turn indicative value includes a target yaw rate, and the actual turn indicative value includes an actual yaw rate generated at the vehicle.

7. The system as claimed in claim 6, wherein the actual yaw rate is estimated from a steering angle and a speed of the vehicle.

8. The system as claimed in claim 1, wherein the target turn indicative value includes a target lateral acceleration, and the actual turn indicative value includes an actual lateral acceleration generated at the vehicle.

9. The system as claimed in claim 8, wherein the actual lateral acceleration is estimated from a steering angle and a speed of the vehicle.

10. The system as claimed in claim 1, further comprising an alarm that generate alarm information and an alarm controller that controls an operation of the alarm, wherein the alarm controller operates the alarm to generate alarm when the controller determines that the vehicle approaches the lane boundary.

11. The system as claimed in claim 1, further comprising a brake actuator that generates a braking force and a brake controller that controls an operation of the brake actuator, wherein the brake controller operates the brake actuator to generate the braking force when the controller determines that the vehicle approaches the lane boundary.

12. The system as claimed in claim 1, further comprising a driving-force generator that generates a driving force of the vehicle and a driving-force controller that controls an operation of the driving-force generator, wherein the driving-force controller controls the driving-force generator to decrease the driving force when the vehicle is approaching the lane boundary.

13. The system as claimed in claim 1, wherein the target position includes a center position between the lane boundaries ahead of the vehicle.

14. A lane deviation determining system of a vehicle comprising:

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

target turn detecting means for detecting a value indicative of a target turn necessary for reaching the vehicle to a target position on the basis of the road shape detected;

actual turn detecting means for detecting a value indicative of an actual turn of the vehicle; and

lane deviation determining means for determining that the vehicle tends to deviate from a traveling lane on the basis of the target turn indicative value and the actual turn indicative value.

15. A method for assisting a lane keep traveling of a vehicle, the method comprising:

taking a view ahead of the vehicle;

detecting a behavior of the vehicle;

calculating a road shape on the basis of the view;

calculating a target turn indicative value indicative of a target turn for reaching the vehicle to a target position, on the basis of the road shape calculated;

calculating an actual turn indicative value indicative of an actual turn of the vehicle on the basis of the behavior of the vehicle; and

determining whether the vehicle approaches a lane boundary of a traveling lane, on the basis of the target turn indicative value and the actual turn indicative value.