VEHICLE BRAKE CONTROL SYSTEM AND METHOD

• US 20070294019A1
• Filed: 05/29/2007
• Published: 12/20/2007
• Est. Priority Date: 06/16/2006
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Nishira, Hikaru, Deguchi, Yoshitaka
• Granted Patent: US 7,729,840 B2
• Time in Patent Office: Days
• US Class Current: 701/70
• CPC Class Codes: B60T 2201/022 Collision avoidance systems
• CPC Class Codes: B60T 2201/03 Brake assistants
• CPC Class Codes: B60T 7/22 initiated by contact of vehicle, e.g. bumper, with an external object, e.g. another vehicle , or by means of contactless obstacle detectors mounted on the vehicle
• CPC Class Codes: B60W 10/196 acting within the driveline, e.g. retarders
• CPC Class Codes: B60W 10/20 including control of steering systems
• CPC Class Codes: B60W 2510/20 Steering systems
• CPC Class Codes: B60W 2540/12 Brake pedal position
• CPC Class Codes: B60W 2540/18 Steering angle
• CPC Class Codes: B60W 30/09 Taking automatic action to avoid collision, e.g. braking and steering
• CPC Class Codes: G08G 1/166 for active traffic, e.g. moving vehicles, pedestrians, bikes

Abstract

A vehicle brake control system is provided with a preceding object detecting section, a running condition detection section, a steering actuation state detecting section, a braking force detecting section, a preceding object avoidability determining section and a braking force control section. The preceding object avoidability determining section determines a possibility of avoiding the preceding object by steering and reducing the current braking force acting on the host vehicle based on the position of the preceding object, the running condition of the host vehicle, the braking force applied to the host vehicle and the steering wheel actuation state that are detected. The braking force control section reduces the current braking force applied by the host vehicle braking system when the preceding object avoidability determining section determines that the preceding object can be avoided by steering and reducing the current braking force acting on the host vehicle.

Claims

1. A vehicle brake control system comprising:

a preceding object detecting section configured to detect a position of a preceding object existing in front of a host vehicle;

a running condition detection section configured to detect a running condition of the host vehicle;

a steering actuation state detecting section configured to detect an actuation state of a steering wheel of the host vehicle;

a braking force detecting section configured to detect a current braking force applied to the host vehicle by a host vehicle braking system;

a preceding object avoidability determining section configured to determine a possibility of avoiding the preceding object by steering and reducing the current braking force acting on the host vehicle based on the position of the preceding object, the running condition of the host vehicle, the braking force applied to the host vehicle and the steering wheel actuation state that are detected; and

a braking force control section configured to reduce the current braking force applied by the host vehicle braking system when the preceding object avoidability determining section determines that the preceding object can be avoided by steering and reducing the current braking force acting on the host vehicle.

2. The vehicle brake control system as recited in claim 1, wherein

the braking force control section is configured to increase the current braking force applied by the host vehicle braking system when the preceding object avoidability determining section determines that the preceding object cannot be avoided by steering and reducing the current braking force acting on the host vehicle.

3. The vehicle brake control system as recited in claim 1, wherein

the preceding object avoidability determining section is further configured to determine the possibility of the host vehicle avoiding the preceding obstacle based on a brake pedal actuation amount being equal to or larger than a prescribed value.

4. The vehicle brake control system as recited in claim 1, wherein

the braking force control section is further configured to control the host vehicle braking system independently of a brake pedal actuation amount.

5. The vehicle brake control system as recited in claim 1, wherein

the braking force control section is configured to increase the current braking force applied to the host vehicle to a larger value than a value corresponding to the brake pedal actuation amount.

6. The vehicle brake control system as recited in claim 1, further comprising

a travel path estimating section configured to estimate a predicted travel path along which the host vehicle will travel based on the steering wheel actuation state and a prescribed braking force applied by the host vehicle braking system, and

the preceding object avoidability determining section being further configured to determine the possibility of avoiding the preceding object based on a positional relationship between the preceding object and the predicted travel path.

7. The vehicle brake control system as recited in claim 6, wherein

the travel path estimating section is further configured estimate the predicted travel path with the prescribed braking force acting on the host vehicle being equal to a current brake pedal requested braking force generated by a brake pedal actuation amount, and

the braking force control section is configured to prohibit increasing the current braking force if the preceding object avoidability determining section determines that the preceding object can be avoided.

8. The vehicle brake control system as recited in claim 6, wherein

the travel path estimating section is configured to estimate the predicted travel path with the prescribed braking force acting on the host vehicle by the host vehicle braking system being equal to zero, and

the braking force control section is configured to prohibit application of a braking force if the preceding object avoidability determining section determines that the preceding object can be avoided based on the predicted travel path.

9. The vehicle brake control system as recited in claim 1, further comprising

a road boundary detecting section configured to detect a road boundary between a travel region in which travel is possible and a non-travel region in which travel is not possible on a road on which the host vehicle is traveling, and

the preceding object avoidability determining section being further configured to determine the possibility of avoiding the preceding object by steering and reducing the current braking force with respect to the road boundary and the preceding object.

10. The vehicle brake control system as recited in claim 1, wherein

the preceding object detecting section is further configured to detect a movement of the preceding object;

and

the preceding object avoidability determining section is further configured to determine the possibility of avoiding the preceding object by steering and reducing the current braking force based on the movement of the preceding object.

11. The vehicle brake control system as recited in claim 1, further comprising

an initial preceding object avoidability determining section configured to determine a possibility of avoiding the preceding object by the current braking force acting on the host vehicle based on the position of the preceding object and a relative velocity of the host vehicle with respect to the preceding object.

12. A vehicle brake control system comprising:

means for detecting a position of a preceding object existing in front of a host vehicle;

means for detecting a running condition of the host vehicle;

means for detecting an actuation state of a steering wheel of the host vehicle;

means for detecting a current braking force applied to the host vehicle by a host vehicle braking system;

object avoidability determining means for determining a possibility of avoiding the preceding object by steering and reducing the current braking force acting on the host vehicle based on the position of the preceding object, the running condition of the host vehicle, the braking force applied to the host vehicle and the steering wheel actuation state that are detected; and

braking force control means for reducing the current braking force applied by the host vehicle braking system when the preceding object avoidability determining section determines that the preceding object can be avoided by steering and reducing the current braking force acting on the host vehicle.

13. A vehicle brake control method comprising:

detecting a position of a preceding object existing in front of a host vehicle;

detecting a running condition of the host vehicle;

detecting an actuation state of a steering wheel of the host vehicle;

detecting a braking force applied to the host vehicle;

executing braking force control upon determining that the host vehicle cannot avoid the preceding object based on the position of the preceding object and the detected running condition of the host vehicle that are detected;

determining if the preceding object can be avoided by steering and reducing the braking force currently acting on the host vehicle based on the position of the preceding object, the running condition of the host vehicle, the braking force applied to the host vehicle, and the steering wheel actuation state that are detected, upon determining that the host vehicle cannot avoid the preceding object; and

executing braking force control to reduce the braking force applied the host vehicle, upon determining that the preceding object can be avoided by steering and reducing the braking force currently acting on the host vehicle.