VEHICLE BEHAVIOR CONTROL APPARATUS

• US 20130304322A1
• Filed: 04/25/2013
• Published: 11/14/2013
• Est. Priority Date: 04/26/2012
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: ISAJI, Kazuyoshi, TSURU, Naohiko, MORIKAWA, Shou
• Granted Patent: US 9,043,088 B2
• Time in Patent Office: Days
• US Class Current: 701/41
• 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: B62D 6/00 Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits means for initiating a change in direction B62D1/00; steering valves B62D5/06; combined with means for inclining the vehicle body or wheels on bends B62D9/00

Abstract

A vehicle behavior control apparatus mounted in a vehicle to control steering of the vehicle. A virtual road outline, which is an outline of a drivable road region where the vehicle will travel, is determined on the basis of detection results from a location sensor. The virtual road outline is reconstructed as a sequence of road segments, such as straight road segments, and right- and left-hand curved road segments. When a current road segment where the vehicle is currently present is a right- or left-hand curved road segment, a subsequent road segment where the vehicle will be present subsequently is tentatively set to a straight road segment until the vehicle reaches the subsequent road segment. The steering angle is controlled so that a virtual-road boundary distance is adapted to a proper distance from the vehicle to a boundary of the virtual road outline situated in front of the vehicle.

Claims

1. A vehicle behavior control apparatus mounted in a vehicle, comprising:

boundary information acquisition means for successively acquiring detection results from a location sensor that successively detects a position of a boundary of a drivable road region situated in front of the vehicle;

current-position acquisition means for successively acquiring a current position of the vehicle;

virtual-road-outline determination means for determining a virtual road outline that is an outline of a drivable road region where the vehicle will travel on the basis of the detection results from the location sensor acquired by the boundary information acquisition means;

reconstruction means for reconstructing the virtual road outline determined by the virtual-road-outline determination means as a sequence of road segments including straight road segments, right-hand curved road segments, and/or left-hand road segments;

first tentatively setting means for, when a current road segment where the vehicle is currently present is a right- or left-hand curved road segment, tentatively setting a subsequent road segment where the vehicle will be present subsequently to the current road segment to a straight road segment until the vehicle reaches the subsequent road segment, even when the subsequent road segment is actually a left- or right-hand curved road segment;

virtual-road boundary distance calculation means for, on the basis of the current position of the vehicle and a portion of the virtual road outline from the current road segment to the subsequent road segment, calculating a virtual-road boundary distance that is a distance from the vehicle to a boundary of the virtual road outline situated in front of the vehicle;

proper-distance calculation means for, on the basis of the portion of the virtual road outline from the current road segment to the subsequent road segment, calculating a proper distance from the vehicle to the boundary of the virtual road outline situated in front of the vehicle;

steering means for controlling a steering angle so that the virtual-road boundary distance calculated by the virtual-road boundary distance calculation means is adapted to the proper distance calculated by the proper-distance calculation means.

2. The apparatus of claim 1, further comprising second tentatively setting means for, when the subsequent road segment is a straight road segment, tentatively setting the subsequent road segment to an extended straight road segment that includes the straight road segment and its straight road extension, until the vehicle reaches the straight road segment as the subsequent road segment.

3. The apparatus of claim 1, further comprising third tentatively setting means for, when the subsequent road segment is a curved road segment that is a right-hand curved road segment or a left-hand curved road segment, tentatively setting the subsequent road segment to an extended curved road segment that includes the curved road segment and its curved road extension, until the own vehicle reaches the curved road segment as the subsequent road segment.

4. The apparatus of claim 1, further comprising travel path information acquisition means for acquiring information about a recommended path along which the own vehicle will travel from a navigation device that searches for the recommended path,

wherein the virtual road outline determination means determines the virtual road outline by using the information acquired by the travel path information acquisition means as additional information.

5. The apparatus of claim 1, further comprising:

steering initiation point determination means for determining a steering initiation point as a function of the virtual road boundary distance when the vehicle is present currently in a straight road segment as the current road segment followed by the right- or left-hand curved road segment as the subsequent road segment;

curve-entrance side start point determination means for determining a point situated a predetermined distance or more away from the steering initiation point in the forward direction of the vehicle as a curve-entrance side start point that is a start point of a virtual curve for a curve-entrance transition area, the curve-entrance transition area extending from the steering initiation point in the straight road segment as the current road segment to a predetermined point in the curved road segment as the subsequent road segment, and the virtual curve for the curve-entrance transition area being here referred to as a curve-entrance side virtual curve;

curve-entrance side virtual curve setting means for setting the curve-entrance side virtual curve such that the travel path of the vehicle draws a relaxation curve when the steering angle is controlled by the steering means according to the proper distance that is a distance from the vehicle to the curve-entrance side virtual curve situated in front of the vehicle, the curve-entrance side virtual curve connecting the curve-entrance side start point determined by the curve-entrance side start point determination means and a curve-entrance side end point that is situated in front of the vehicle at the predetermined point,

wherein the proper-distance calculation means, while the vehicle is traveling in the curve-entrance transition area, calculates a distance from the vehicle to the curve-entrance side virtual curve situated in front of the vehicle as the proper distance.

6. The apparatus of claim 5, further comprising:

steering initiation indicator calculation means for calculating a steering initiation indicator KdB_e that is indicative of a status of the vehicle approaching the virtual-road boundary situated in front of the vehicle, which indicator is expressed as a function of a speed of the vehicle approaching the virtual-road boundary situated in front of the vehicle, the indicator KdB_e increasing with increasing approaching speed of the vehicle approaching the virtual-road boundary situated in front of the vehicle and the rate of increase in steering initiation indicator KdB_e with decreasing virtual-road boundary distance increasing more rapidly with decreasing virtual-road boundary distance;

steering initiation determination means for determining whether or not a current value KdB_e_p of the steering initiation indicator is greater than a threshold KdB_e_str of the steering initiation indicator that is defined as a function of a distance from the vehicle to the virtual-road boundary situated in front of the vehicle; and

steering initiation means for, when it is determined by the steering initiation determination means that the current value KdB_e_p of the steering initiation indicator is greater than the threshold KdB_e_str of the steering initiation indicator, initiating the steering of the vehicle,

wherein the steering initiation point determination means determines the current position of the vehicle when it is determined by the steering initiation determination means that the current value KdB_e_p of the steering initiation indicator is greater than the threshold KdB_e_str of the steering initiation indicator as the steering initiation point.

7. The apparatus of claim 6, wherein

the steering initiation indicator KdB_e is calculated using the following equation:

8. The apparatus of claim 1, further comprising:

curve-exit determination means for determining an exit point of a curved road segment as the current road segment on the basis of an outline of the curved road segment;

reverse steering initiation point determination means for determining a position of the vehicle such that an intersection point of a virtual-road boundary of a right- or left-hand curved road segment as the current road segment and a virtual-road boundary of a straight road segment as the subsequent road segment is situated in front of the vehicle as a reverse steering initiation point;

curve-exit side start point determination means for determining the intersection point as a curve-exit side start point;

steering termination point determination means for determining the exit point determined by the curve-exit determination means as a steering termination point;

curve-exit side end point determination means for determining a point that is away from the exit point determined by the curve-exit determination means by a distance as a function of a speed of the vehicle and is situated along the widthwise centerline of a straight road segment situated forward of the exit point as a curve-exit side end point;

curve-exit side virtual curve setting means for setting a curve-exit side virtual curve such that the travel path of the vehicle draws a relaxation curve when the steering angle is controlled by the steering means according to the proper distance that is a distance from the vehicle to the curve-exit side virtual curve situated in front of the vehicle, the curve-exit side virtual curve connecting the curve-exit side start point determined by the curve-exit side start point determination means and the curve-exit side end point determined by the curve-exit side end point determination means,

wherein the proper-distance calculation means, while the vehicle is traveling in the curve-exit transition area, calculates a distance from the vehicle to the curve-exit side virtual curve situated in front of the vehicle as the proper distance.

9. The apparatus of claim 1, further comprising:

tire turning angle calculation means for calculating a tire turning angle θ

required to adapt the virtual-road boundary distance to the proper distance; and

steering angle calculation means for calculating a steering angle ⊖

as a function of the tire turning angle,

wherein the steering means controls the steering angle so as to be adapted to the steering angle calculated by the steering angle calculation means.

10. The apparatus of claim 9, wherein

the tire turning angle calculation means calculates an outer curvature radius Ra of a curve along which the vehicle is turning using the proper distance calculated by the proper-distance calculation means and the following equation:

11. The apparatus of claim 1, further comprising:

real-road boundary determination means for determining positions of boundaries of a real road on the basis of the detection results from the location sensor;

lateral displacement means for, when the vehicle is present in a straight road segment, displacing the vehicle toward the centerline of the corresponding real straight road by a lateral deviation C_offset_real so that the lateral center of the vehicle lies on the centerline of the corresponding real straight road bordered by the boundaries detected by the real-road boundary determination means, and when the vehicle is present in a right- or left-hand curved road segment, displacing the vehicle by a lateral deviation C_offset_real so that the lateral center of the vehicle lies on the centerline of the corresponding real curve bordered by the boundaries detected by the real-road boundary determination means;

steering angle correction means for, on the basis of the straight road segment when the vehicle is present in the straight road segment or a straight road segment extending in the tangential direction to the boundaries of the curved road segment when the vehicle is present in the curved road segment, calculating a steering angle ⊖

required to bring the vehicle back to the centerline of the straight road segment, the steering angle ⊖

being derived from the following equations;

Θ

=N×

θ

<sub>—

c</sub>

where N is a ratio of the steering angle ⊖

to the tire turning angle θ

, and θ

_c is the tire turning angle that is required to bring the vehicle back to the centerline of the straight road segment,

θ

_—

c=θ

_—

1+θ

_—

2

where θ

_—

1 is a tire turning angle required to set an angle between the traveling direction of the vehicle and the centerline of the straight road segment to zero, and θ

_—

2 is a tire turning angle required to set an lateral deviation of the lateral center of the vehicle from the centerline of the straight road segment to zero,

12. The apparatus of claim 5, wherein the relaxation curve is a clothoid curve.

13. The apparatus of claim 5, wherein an intersection point of the curve-entrance side virtual curve and an outer boundary of the curved road segment as the subsequent road segment is determined as the curve-entrance side end point.

14. A vehicle behavior control apparatus mounted in a vehicle and configured to acquire information via a communication device that transmits and receives information via inter-vehicle communications, the apparatus comprising:

current-position acquisition means for successively acquiring a current position of the vehicle;

preceding-vehicle information acquisition means for successively acquiring preceding-vehicle information via the communication device, the preceding-vehicle information being information successively transmitted from an inter-vehicle communication enabled preceding vehicle and used to determine a virtual road outline that is an outline of a drivable road region where the vehicle will travel as a function of a travel path of the preceding vehicle;

virtual-road-outline determination means for determining the virtual road outline on the basis of the preceding vehicle information acquired by the preceding-vehicle information acquisition means;

reconstruction means for reconstructing the virtual road outline determined by the virtual-road-outline determination means as a sequence of road segments including straight road segments, right-hand curved road segments, and/or left-hand road segments;

first tentatively setting means for, when a current road segment where the vehicle is currently present is a right- or left-hand curved road segment, tentatively setting a subsequent road segment where the vehicle will be present subsequently to the current road segment to a straight road segment until the vehicle reaches the subsequent road segment, even when the subsequent road segment is actually a left- or right-hand curved road segment;

virtual-road boundary distance calculation means for, on the basis of the current position of the vehicle and a portion of the virtual road outline from the current road segment to the subsequent road segment, calculating a virtual-road boundary distance that is a distance from the vehicle to a boundary of the virtual road outline situated in front of the vehicle;

proper-distance calculation means for, on the basis of the portion of the virtual road outline from the current road segment to the subsequent road segment, calculating a proper distance from the vehicle to the boundary of the virtual road outline situated in front of the vehicle;

steering means for controlling a steering angle so that the virtual-road boundary distance calculated by the virtual-road boundary distance calculation means is adapted to the proper distance calculated by the proper-distance calculation means.

15. A vehicle behavior control apparatus mounted in a vehicle and adapted to successively acquire, via a communication device, information transmitted from a roadside device via vehicle-roadside communications, the apparatus comprising:

current-position acquisition means for successively acquiring a current position of the vehicle;

virtual-road-outline determination information acquisition means for successively acquiring virtual-road-outline determination information via the communication device, the virtual-road-outline determination information being information transmitted from the roadside device and used to determine a virtual road outline that is an outline of a drivable road region where the vehicle will travel;

virtual-road-outline determination means for determining the virtual road outline on the basis of the virtual-road-outline determination information acquired by virtual-road-outline determination information acquisition means;

reconstruction means for reconstructing the virtual road outline determined by the virtual-road-outline determination means as a sequence of road segments including straight road segments, right-hand curved road segments, and/or left-hand road segments;

first tentatively setting means for, when a current road segment where the vehicle is currently present is a right- or left-hand curved road segment, tentatively setting a subsequent road segment where the vehicle will be present subsequently to the current road segment to a straight road segment until the vehicle reaches the subsequent road segment, even when the subsequent road segment is actually a left- or right-hand curved road segment;

virtual-road boundary distance calculation means for, on the basis of the current position of the vehicle and a portion of the virtual road outline from the current road segment to the subsequent road segment, calculating a virtual-road boundary distance that is a distance from the vehicle to a boundary of the virtual road outline situated in front of the vehicle;

proper-distance calculation means for, on the basis of the portion of the virtual road outline from the current road segment to the subsequent road segment, calculating a proper distance from the vehicle to the boundary of the virtual road outline situated in front of the vehicle;

steering means for controlling a steering angle so that the virtual-road boundary distance calculated by the virtual-road boundary distance calculation means is adapted to the proper distance calculated by the proper-distance calculation means.