Vehicle travel control system

• US 20080185207A1
• Filed: 02/04/2008
• Published: 08/07/2008
• Est. Priority Date: 02/06/2007
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Kondoh, Toshiyuki
• Granted Patent: US 8,068,968 B2
• Time in Patent Office: Days
• US Class Current: 180/272
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/184 with wheel brakes
• CPC Class Codes: B60W 2040/0818 Inactivity or incapacity of driver
• CPC Class Codes: B60W 2540/22 Psychological state; Stress level or workload
• CPC Class Codes: B60W 2540/221 Physiology, e.g. weight, heartbeat, health or special needs
• CPC Class Codes: B60W 2554/00 Input parameters relating to objects
• CPC Class Codes: B60W 2554/4047 Attentiveness, e.g. distracted by mobile phone
• CPC Class Codes: B60W 30/16 Control of distance between vehicles, e.g. keeping a distance to preceding vehicle
• CPC Class Codes: B60W 40/04 Traffic conditions
• CPC Class Codes: B60W 40/08 related to drivers or passengers

Abstract

A vehicle travel control system includes a cruise control ECU, an engine control ECU and a brake control ECU. The cruise control ECU checks whether a driver'"'"'s actual concentration degree is insufficient relative to a required concentration degree in terms of safety in surrounding environments of the subject vehicle. When such possibility arises, even during the cruise control, the speed of the subject vehicle is controlled to match a control vehicle speed lower than a set vehicle speed or a control distance to a preceding vehicle.

Claims

1. A vehicle travel control system comprising:

a cruise control means that automatically drives a subject vehicle without a driver'"'"'s cruise operation for adjusting a cruise speed of the subject vehicle;

an actual concentration degree detecting means that detects a driver'"'"'s actual concentration degree based on a state of the driver; and

a control change means that changes a control content in the cruise control means based on the actual concentration degree detected by the actual concentration degree detecting means.

2. The vehicle travel control system according to claim 1, further comprising:

a required concentration degree acquiring means that acquires a required concentration degree required to the driver for safely cruising the subject vehicle based on surrounding environments of the subject vehicle,

wherein the control change means changes the control content in the cruise control means based on a relationship between the required concentration degree and the actual concentration degree.

3. The vehicle travel control system according to claim 2, wherein:

the cruise control means drives the subject vehicle at a fixed vehicle speed; and

the control change means changes the control content in the cruise control means to drive the subject vehicle at a speed lower than the fixed vehicle speed, when the actual concentration degree falls short of the required concentration degree.

4. The vehicle travel control system according to claim 3, wherein:

the required concentration degree acquiring means sets the required concentration degree to become small as the cruise speed of the subject vehicle becomes low; and

the control change means changes the control content in the cruise control means to decrease a speed at which the cruise control means drives the subject vehicle until the required concentration degree becomes smaller than the actual concentration degree by a specific value.

5. The vehicle travel control system according to claim 3, wherein:

the required concentration degree acquiring means acquires the required concentration degree based on information of at least one of the surrounding environment of the subject vehicle, a preceding vehicle inter-vehicle time obtained by dividing a vehicular distance from a preceding vehicle traveling on a same lane as the subject vehicle by the vehicle speed of the subject vehicle, a curve entrance margin time obtained by dividing a distance to a curve entrance point by the vehicle speed, a visibility distance time obtained by dividing a visible distance set based on a road width by the vehicle speed, and an adjacent vehicle inter-vehicle time obtained by dividing a vehicular distance from an adjacent vehicle traveling on an adjacent lane by the vehicle speed of the subject vehicle.

6. The vehicle travel control system according to claim 2, wherein:

the cruise control means drives the subject vehicle to follow a preceding vehicle with a specific vehicular distance corresponding to the speed of the subject vehicle; and

the control change means changes the control content in the cruise control means to increase a vehicular distance from the preceding vehicle, when the actual concentration degree falls short of the required concentration degree.

7. The vehicle travel control system according to claim 6, wherein:

the required concentration degree acquiring means sets the required concentration degree to become smaller as the vehicular distance from the preceding vehicle becomes longer; and

the control change means changes the control content in the cruise control means to lengthen a vehicular distance controlled by the cruise control means until the required concentration degree becomes smaller than the actual concentration degree by a specific value.

8. The vehicle travel control system according to claim 6, wherein:

the required concentration degree acquiring means acquires the required concentration degree based on information of at least one of the surrounding environment of the subject vehicle, a preceding vehicle inter-vehicle time obtained by dividing the vehicular distance from the preceding vehicle traveling on a same lane as the subject vehicle by the vehicle speed of the subject vehicle, and an adjacent vehicle inter-vehicle time obtained by dividing the vehicular distance from an adjacent vehicle traveling on an adjacent lane by the vehicle speed of the subject vehicle.

9. The vehicle travel control system according to claim 1, wherein:

the actual concentration degree detecting means uses an opening degree of a driver'"'"'s eyelid as the state of the driver to detect the actual concentration degree.

10. The vehicle travel control system according to claim 1, wherein:

the actual concentration degree detecting means uses an opening degree of the driver'"'"'s eyelid and time duration of the eyelid opening as the state of the driver to detect the actual concentration degree, when the eyelid opening degree is less than a specific value.

11. The vehicle travel control system according to claim 1, wherein:

the actual concentration degree detecting means uses a driver'"'"'s eye direction and time duration of the driver'"'"'s eye direction as the state of the driver to detect the actual concentration degree, when the detected eye direction of the driver is a specific angle or more off a traveling direction of the subject vehicle.

12. The vehicle travel control system according to claim 1, wherein:

the actual concentration degree detecting means uses, as the state of the driver, a time ratio that an angle value of the driver'"'"'s eye direction is a specific angle or more off a traveling direction of the subject vehicle in a specific time interval as the state of the driver to detect the actual concentration degree.

13. The vehicle travel control system according to claim 1, wherein:

the actual concentration degree detecting means uses, as the state of the driver, a degree of fluctuation in angle of a steering wheel operated by the driver to detect the actual concentration degree.

14. The vehicle travel control system according to claim 1, wherein:

the actual concentration degree detecting means uses a slack degree of muscle of a photographed face of the driver as the state of the driver to detect the actual concentration degree based.

15. The vehicle travel control system according to claim 3, wherein:

the required concentration degree acquiring means acquires the required concentration degree based on a distance from a person existing ahead of the subject vehicle, as information about the surrounding environment of the subject vehicle.

16. The vehicle travel control system according to claim 3, wherein:

the required concentration degree acquiring means acquires the required concentration degree based on a distance from a traffic signal existing forward of the subject vehicle as information of the surrounding environment of the subject vehicle.

17. The vehicle travel control system according to claim 3, wherein:

the required concentration degree acquiring means acquires the required concentration degree based on weather during cruising of the subject vehicle as information of the surrounding environment of the subject vehicle.

18. The vehicle travel control system according to claim 6, wherein:

the required concentration degree acquiring means acquires the required concentration degree based on a distance from a person existing ahead of the subject vehicle, as information about the surrounding environment of the subject vehicle.

19. The vehicle travel control system according to claim 6, wherein:

the required concentration degree acquiring means acquires the required concentration degree based on a distance from a traffic signal existing forward of the subject vehicle as information of the surrounding environment of the subject vehicle.

20. The vehicle travel control system according to claim 6, wherein:

the required concentration degree acquiring means acquires the required concentration degree based on weather during cruising of the subject vehicle as information of the surrounding environment of the subject vehicle.