SPEED CONTROL APPARATUS FOR VEHICLE

• US 20110035131A1
• Filed: 08/03/2010
• Published: 02/10/2011
• Est. Priority Date: 08/05/2009
• Status: Active Grant

• Current Assignee: Advics Company Limited (Aisin Corp.)
• Original Assignee: Advics Company Limited (Aisin Corp.)
• Inventors: KOTO, Hideaki, Miyajima, Takayuki, Yasui, Yoshiyuki, Tanaka, Manabu
• Granted Patent: US 8,892,329 B2
• Time in Patent Office: Days
• US Class Current: 701/93
• CPC Class Codes: B60W 2552/20 Road profile, i.e. the change in elevation or curvature of a plurality of continuous road segments
• CPC Class Codes: B60W 2552/30 Road curve radius
• CPC Class Codes: B60W 30/146 Speed limiting
• CPC Class Codes: B60W 30/18145 Cornering

Abstract

A plurality of position data sets representing a plurality of points on a road ahead of a vehicle are acquired, and the degree of curvature of the road at each point is computed. On the basis of the degree of curvature, a constant curvature degree section of a curve is identified, and the degree of curvature and the end position of the constant curvature degree section are determined. In order to cause the vehicle to properly pass through the curve, curve deceleration control is executed on the basis of the actual vehicle speed, a proper vehicle speed determined from the degree of curvature, and the end position of the constant curvature degree section. That is, the curve deceleration control is performed on the basis of the start point of a section of a curve having the maximum degree of curvature and the constant degree of curvature of that section.

Claims

1. A speed control apparatus for a vehicle comprising:

vehicle speed acquisition means for acquiring an actual speed of the vehicle;

vehicle position acquisition means for acquiring a position of the vehicle;

position data acquisition means for acquiring position data sets representing positions of a plurality of points on a road located ahead of the vehicle traveling on the road;

curvature degree acquisition means for acquiring a degree of curvature of the road at each of the points;

constant curvature degree section identification means for identifying a constant curvature degree section whose degree of curvature is constant on the basis of the plurality of position data sets and the degree of curvature at each point;

constant curvature degree acquisition means for acquiring a constant degree of curvature of the constant curvature degree section;

end position determination means for determining positions of end points of the constant curvature degree section; and

control means for executing vehicle speed control, which controls the speed of the vehicle, on the basis of the actual speed of the vehicle, the position of the vehicle, the constant degree of curvature of the constant curvature degree section corresponding to a curve section of the road, and the position of an end point of the constant curvature degree section corresponding to the curve section.

2. A speed control apparatus for a vehicle according to claim 1, wherein the curvature degree acquisition means determines a first point, a second point, and a third point on the road on the basis of the plurality of position data sets;

computes a first perpendicular bisector of a line whose opposite ends are located at the first point and the second point, and a second perpendicular bisector of a line whose opposite ends are located at the second point and the third point; and

computes the degree of curvature at the second point on the basis of an intersection between the first perpendicular bisector and the second perpendicular bisector.

3. A speed control apparatus for a vehicle according to claim 2, wherein the control means computes a first target vehicle speed of the vehicle on the basis of the constant degree of curvature of the constant curvature degree section corresponding to the curve section of the road and the position of an end point of the constant curvature degree section corresponding to the curve section;

and executes the vehicle speed control on the basis of the result of comparison between the first target vehicle speed and the actual speed of the vehicle.

4. A speed control apparatus for a vehicle according to claim 1, wherein the control means computes a first target vehicle speed of the vehicle on the basis of the constant degree of curvature of the constant curvature degree section corresponding to the curve section of the road and the position of an end point of the constant curvature degree section corresponding to the curve section;

and executes the vehicle speed control on the basis of the result of comparison between the first target vehicle speed and the actual speed of the vehicle.

5. A speed control apparatus for a vehicle according to claim 2, wherein the control means computes a second target vehicle speed of the vehicle on the basis of the constant degree of curvature of the constant curvature degree section corresponding to the curve section of the road, the position of an end point of the constant curvature degree section corresponding to the curve section, the position of an end point of the constant curvature degree section corresponding to a straight section of the road;

and executes the vehicle speed control on the basis of the result of comparison between the second target vehicle speed and the actual speed of the vehicle.

6. A speed control apparatus for a vehicle according to claim 1, wherein the control means computes a second target vehicle speed of the vehicle on the basis of the constant degree of curvature of the constant curvature degree section corresponding to the curve section of the road, the position of an end point of the constant curvature degree section corresponding to the curve section, the position of an end point of the constant curvature degree section corresponding to a straight section of the road;

and executes the vehicle speed control on the basis of the result of comparison between the second target vehicle speed and the actual speed of the vehicle.

7. A speed control apparatus for a vehicle according to claim 2, wherein the control means computes a first target vehicle speed of the vehicle on the basis of the constant degree of curvature of the constant curvature degree section corresponding to the curve section of the road and the position of an end point of the constant curvature degree section corresponding to the curve section;

computes a second target vehicle speed of the vehicle on the basis of the constant degree of curvature of the constant curvature degree section corresponding to the curve section, the position of the end point of the constant curvature degree section corresponding to the curve section, the position of an end point of the constant curvature degree section corresponding to a straight section of the road;

selecting smaller one of the first target vehicle speed and the second target vehicle speed as a final target vehicle speed; and

executes the vehicle speed control on the basis of the result of comparison between the final target vehicle speed and the actual speed of the vehicle.

8. A speed control apparatus for a vehicle according to claim 1, wherein the control means computes a first target vehicle speed of the vehicle on the basis of the constant degree of curvature of the constant curvature degree section corresponding to the curve section of the road and the position of an end point of the constant curvature degree section corresponding to the curve section;

computes a second target vehicle speed of the vehicle on the basis of the constant degree of curvature of the constant curvature degree section corresponding to the curve section, the position of the end point of the constant curvature degree section corresponding to the curve section, the position of an end point of the constant curvature degree section corresponding to a straight section of the road;

selecting smaller one of the first target vehicle speed and the second target vehicle speed as a final target vehicle speed; and

executes the vehicle speed control on the basis of the result of comparison between the final target vehicle speed and the actual speed of the vehicle.

9. A speed control apparatus for a vehicle according to claim 1, further comprising:

determination means for determining, on the basis of the position of the vehicle and the position of an end point of the constant curvature degree section corresponding to a straight section of the road, whether or not the vehicle speed control is to be executed, and setting, on the basis of the result of the determination, an output signal therefrom to a permission state for permitting execution of the vehicle speed control or a prohibition state for prohibiting execution of the vehicle speed control,

wherein the control means executes the vehicle speed control when the output signal is in the permission state, and does not execute the vehicle speed control when the output signal is in the prohibition state.

10. A speed control apparatus for a vehicle according to claim 9, wherein the determination means switches the output signal from the prohibition state to the permission state when the position of the vehicle passes through the end point of the constant curvature degree section corresponding to the straight section.

11. A speed control apparatus for a vehicle according to claim 9, further comprising:

turning amount acquisition means for acquiring a turning amount representing the degree of turning motion of the vehicle,

wherein the determination means starts computation of a cumulative value of the turning amount on the basis of the position of the vehicle and the position of the end point of the constant curvature degree section corresponding to the straight section, and switches the output signal from the prohibition state to the permission state when the cumulative value exceeds a predetermined value.