Traffic lane deviation preventing system for a vehicle

Abstract

A traffic lane deviation preventing system includes traffic line detecting unit for detecting traffic line positions on a road, control unit for determining a possibility of its vehicle's deviation from a traffic line based on the traffic line positions detected by the traffic line detecting unit, setting a travel target point to which the vehicle is to travel if it is determined that there is a possibility of the traffic line deviation. The control unit moves the travel target point toward the center of a traffic lane according to the passage of the control operation time.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of the configuration of a traffic lane deviation preventing system according to an embodiment of the invention;

FIG. 2 is a block diagram of the configuration of traffic line detecting means according to the embodiment;

FIG. 3 is a view of an example of a reference image;

FIG. 4 is a view showing right and left traffic lines detected on the reference image;

FIG. 5 is a plot of points on a real space representing distances of segments of a distance image;

FIG. 6 is a plot showing the points in FIG. 5 as they are grouped;

FIG. 7 is a plot showing objects and side walls detected by labeling the groups shown in FIG. 6;

FIG. 8 is a view of a reference image having frame lines representing objects or side walls superposed thereon;

FIG. 9 is a block diagram of the configuration of control means according to the embodiment;

FIG. 10 is a view for use in illustrating a travel track, the positions of right and left traffic lines, and first and second determination lines specified on a real space;

FIG. 11 is a view showing a travel target point set on a traffic lane at the start of control operation by deviation preventing control;

FIG. 12 is a view showing a travel target point set immediately in front of the vehicle at the start of control operation by deviation preventing control;

FIG. 13 shows a travel target point that moves toward the center of the traffic lane for each sampling cycle;

FIG. 14 is a view a determined driving line;

FIG. 15 is a view for use in illustrating a case in which an obstacle is detected in a lane for example by on-road parking or the like;

FIG. 16 is a view showing how the vehicle enters the adjacent traffic lane by a lane change;

FIG. 17 is a view showing the vehicle traveling across a traffic line;

FIG. 18 shows a track of the vehicle achieved by the traffic deviation preventing system according to the embodiment;

FIG. 19 is a view showing a travel target point set on the outer side of a traffic line from which the vehicle is likely to deviate; and

FIGS. 20 and 21 each show a track of the vehicle achieved by a conventional deviation preventing system.

Claims

1. A traffic lane deviation preventing system for a vehicle, comprising: traffic line detecting means for detecting the position of a traffic line on a road;control means for determining a possibility of vehicle's deviation from the traffic line based on the position of the traffic line detected by said traffic line detecting means,said control means carrying out deviation preventing control by setting a travel target point to which the vehicle should travel and transmitting a signal to a responsive unit so that the vehicle travels to the travel target point if the deviation from the traffic line is possible; andcount means for counting the passage of control operation time of said deviation preventing control, whereinsaid control means controlling said travel target point to move in a direction toward the center of a traffic lane in which the vehicle travels as said control operation time counted by said count means passes.

2. The traffic lane deviation preventing system for a vehicle according to claim 1, wherein if the traffic line position is no longer detected by said traffic line detecting means after the start of control operation by said deviation preventing control, said control means continues to move said travel target point based on the previously detected position of the traffic line and continues the control operation by said deviation preventing control.

3. The traffic lane deviation preventing system for a vehicle according to claim 1, wherein said control means sets said travel target point set for the first time to a point a prescribed distance ahead of the vehicle and a distance equal to a half of the vehicle width apart from the traffic line from which the vehicle is likely to deviate.

4. The traffic lane deviation preventing system for a vehicle according to claim 1, wherein said control means sets said travel target point set for the first time to a point a prescribed distance ahead of the vehicle and apart from the traffic line by the present distance between the vehicle and the traffic line from which the vehicle is likely to deviate.

5. The traffic lane deviation preventing system for a vehicle according to claim 1, wherein said control means sets said travel target point set for the first time to a point a prescribed distance ahead of the vehicle where a change at most equal to a prescribed threshold is generated in at least one of the yaw rate, the steering wheel torque, and the steering wheel angle of the steering wheel of the vehicle.

6. The traffic lane deviation preventing system for a vehicle according to claim 1, wherein said control means sets said travel target point set for the first time to a point a prescribed distance ahead of the vehicle where a change larger than a prescribed threshold is generated in at least one of the yaw rate, the steering wheel torque, and the steering wheel angle of the steering wheel of the vehicle.

7. The traffic lane deviation preventing system for a vehicle according to claim 1, wherein said control means moves said travel target point in said direction toward the center of said traffic lane by a prescribed distance per unit time.

8. The traffic lane deviation preventing system for a vehicle according to claim 1, wherein said control means moves said travel target point so that the position of said travel target point at the end of the control operation by said deviation preventing control is in the center of a traffic lane calculated from the positions of traffic lines on the right and left of the vehicle detected by said traffic line detecting means.

9. The traffic lane deviation preventing system for a vehicle according to claim 1, wherein said control means moves said travel target point so that said travel target point at the end of the control operation by said deviation preventing control is apart by a distance equal to a half of the vehicle width from a traffic line from which the vehicle is likely to deviate.

10. The traffic lane deviation preventing system for a vehicle according to claim 1, wherein if said travel target point reaches a prescribed position before said control operation time counted by said count means reaches predetermined time, said control means ends the control operation by said deviation preventing control.

11. The traffic lane deviation preventing system for a vehicle according to claim 10, wherein said prescribed position is in the center of a traffic lane calculated from the positions of traffic lines on the right and left of the vehicle detected by said traffic line detecting means.

12. The traffic lane deviation preventing system for a vehicle according to claim 1, wherein said control means ends the control operation by said deviation preventing control when an end of the vehicle deviating from a traffic line protrudes from the traffic line at least by a prescribed distance on the outer side of the traffic line.

13. The traffic lane deviation preventing system for a vehicle according to claim 1, wherein, after said control operation ends the control operation by said deviation preventing control, said control means does not start control operation by the deviation preventing control when the vehicle moves away from the traffic line or continues to move across the traffic line.

14. The traffic lane deviation preventing system for a vehicle according to claim 1, wherein said control means ends the control operation by said deviation preventing control when the steering of the steering wheel by the driver of the vehicle is detected.

15. The traffic lane deviation preventing system for a vehicle according to claim 14, wherein the steering of the steering wheel by said driver is detected at least any of when a steering wheel torque exceeding a prescribed threshold is input from the steering torque sensor, when a steering wheel torque continues to be input for a period exceeding prescribed duration, and when a differential value of the steering wheel angle of the steering wheel input from the steering wheel angle sensor exceeds a prescribed threshold.

16. The traffic lane deviation preventing system for a vehicle according to claim 1, further comprising solid object detecting means for detecting a solid object in an image produced by image-sensing a path ahead of the running vehicle including a road, wherein, when a solid object is detected by said solid object detecting means on the side of a traffic line from which the vehicle is likely to deviate, said control means shortens the control operation time set at said count means and increases the moving distance of said travel target point per unit time.

17. The traffic lane deviation preventing system for a vehicle according to claim 1, further comprising solid object detecting means for detecting a solid object in an image produced by image-sensing a path ahead of the running vehicle including a road, wherein, when a solid object is detected by said solid object detecting means on a traffic line on the opposite side to the traffic line from which the vehicle is likely to deviate, said control means stops the movement of said travel target point in a location a prescribed distance apart from said solid object or ends the control operation by said deviation preventing control.

18. The traffic lane deviation preventing system for a vehicle according to claim 1, wherein said control means makes an indication at a display connected thereto or outputs an audio sound for notifying that the deviation preventing control is active.

19. The traffic lane deviation preventing system for a vehicle according to claim 1, wherein if the traffic line from which the vehicle is likely to deviate is indicated as a continuous line, said control means sets control operation time shorter than control operation time by deviation preventing control set for a traffic line indicated as a broken line.

20. The traffic lane deviation preventing system for a vehicle according to claim 1, further comprising wakefulness estimating means for estimating the wakefulness of the driver, wherein said control means shortens the control operation time set at said count means and increases the moving distance of said travel target point per unit time if it is determined that the wakefulness of the driver is low based on an estimation result by said wakefulness estimating means.