VEHICLE HEADWAY MAINTENANCE ASSIST SYSTEM AND METHOD

Abstract

A vehicle headway maintenance assist system is provided that provides a haptic notification to an accelerator to alert the driver under prescribed conditions. The system changes a drive force/accelerator actuation relationship between an accelerator actuation amount and a target drive force or torque under the prescribed conditions. In particular, system changes a first drive force/accelerator actuation relationship to a second drive force/accelerator actuation relationship based on a vehicle running condition that was detected so that the driver more readily notices the haptic notification (e.g., an accelerator actuation reaction force) when the haptic notification is being applied to the accelerator to alert the driver under the prescribed conditions.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the attached drawings which form a part of this original disclosure:

FIG. 1 is a vehicle is schematically illustrated with a vehicle headway maintenance assist system in accordance with a first embodiment of the present invention;

FIG. 2 is a flowchart showing the processing executed by the headway maintenance assist system in accordance with the first embodiment of the present invention;

FIG. 3 is a flowchart showing the processing executed for calculating the first headway distance threshold L*1 in the headway maintenance assist system of the first embodiment of the present invention;

FIG. 4 is a flowchart showing the processing executed for calculating the second headway distance threshold L*2 in the headway maintenance assist system of the first embodiment of the present invention

FIG. 5 is a flowchart showing the processing executed for controlling the reaction force that is imparted to the accelerator pedal in the headway maintenance assist system of the first embodiment;

FIG. 6 is a diagram showing the relationship between the gain Kr2 and the acceleration/deceleration speed αa of the preceding vehicle;

FIG. 7 is a flowchart showing the processing executed for controlling the changes in the relationship between the target drive force and the position of the accelerator pedal;

FIG. 8 is a diagram showing the relationship between the vehicle speed V and the accelerator pedal position Acc;

FIG. 9 is a diagram showing the relationship between the accelerator pedal position Acc and the target drive force τ*t after a change in the correspondence relationship;

FIG. 10 is a diagram showing another example of the relationship between the accelerator pedal position Acc and the target drive force τ*t;

FIG. 11 is a diagram showing an example of the relationship between the speed V of the host vehicle and the headway distance threshold parameter (i.e., the upper limit Ta_max);

FIG. 12 is a diagram showing an example of the relationship between the accelerator pedal position Acc and the target drive force τ*t that illustrates the relationship between the speed V of the host vehicle and the upper limit Ta_max;

FIG. 13 is a diagram showing the headway distance threshold L* when the driver ceases to operate (depress) the accelerator pedal; and

FIG. 14 is a diagram showing the relationship between the relative speed Vr and the gain Kr.

Claims

1. A vehicle headway maintenance assist system comprising: a preceding vehicle detection section configured to detect a headway distance between a host vehicle and a preceding vehicle;an accelerator actuation amount detection section configured to detect an accelerator actuation amount of an accelerator of the host vehicle;a reaction force computing section configured to calculate a reaction force to be generated in the accelerator based on the headway distance detected by the preceding vehicle detection section;a reaction force generating section configured to generate the reaction force calculated by the reaction force computing section in the accelerator;a running condition detection section configured to detect a running condition of the host vehicle;a driving force determination section configured to determine a target driving force of the host vehicle in accordance with the accelerator actuation amount detected by the accelerator actuation amount detection section;a drive source control section configured to control an output of a drive source towards the driving force determined by the driving force determination section; anda compensation section configured to increase a driver awareness of the reaction force generated in the accelerator by changing from a first drive force/accelerator actuation relationship between the target drive force determined by the driving force determination section and the accelerator actuation amount detected by the accelerator actuation amount detection section to a second drive force/accelerator actuation relationship based on the running condition detected by the running condition detection section.

2. The vehicle headway maintenance assist system according to claim 1, wherein the compensation section is configured to change the first drive force/accelerator actuation relationship so that the target drive force is reduced with respect to the accelerator actuation amount in the second drive force/accelerator actuation relationship.

3. The vehicle headway maintenance assist system according to claim 1, wherein the compensation section is configured to set an offset amount of the accelerator actuation amount detected by the accelerator actuation amount detection section for changing the first drive force/accelerator actuation relationship to the second drive force/accelerator actuation relationship.

4. The vehicle headway maintenance assist system according to claim 3, wherein the compensation section is configured to change the target drive force determined by the driving force determination section to zero when the accelerator actuation amount detected by the accelerator actuation amount detection section is less than the offset amount.

5. The vehicle headway maintenance assist system according to claim 3, wherein the compensation section is configured to change a magnitude of the offset amount in accordance with the running condition of the host vehicle detected by the running condition detection section.

6. The vehicle headway maintenance assist system according to claim 1, wherein the compensation section is further configured to prohibit changing the first drive force/accelerator actuation relationship to the second drive force/accelerator actuation relationship when the accelerator actuation amount detected by the accelerator actuation amount detection section has exceeded a prescribed value.

7. The vehicle headway maintenance assist system according to claim 1, wherein the running condition detection section is further configured to calculate a approach rate between the host vehicle and the preceding vehicle based on the headway distance detected by the preceding vehicle detection section; andthe compensation section is configured to change the first drive force/accelerator actuation relationship to the second drive force/accelerator actuation relationship so that the target drive force decreases with respect to the accelerator actuation amount as the approach rate increases.

8. The vehicle headway maintenance assist system according to claim 1, wherein the running condition detection section is configured to detect at least one of a vehicle speed, a rotational speed of an output shaft of the drive source, a state of a transmission for reducing and transmitting a speed of the output of the drive source to a drive wheel, and a road surface inclination as the running condition that is used by the compensation section.

9. The vehicle headway maintenance assist system according to claim 1, wherein the compensation section is configured to change the target drive force determined by the driving force determination section.

10. The vehicle headway maintenance assist system according to claim 1, wherein the compensation section is configured to change the accelerator actuation amount detected by the accelerator actuation amount detection section and outputs a compensated accelerator actuation amount to be used by the driving force determination section in determining the target drive force.

11. The vehicle headway maintenance assist system according to claim 1, wherein the running condition detection section is further configured to determine whether the reaction force generating section is in an operable state as the running condition that is used by the compensation section; andthe compensation section is configured to change the first drive force/accelerator actuation relationship to the second drive force/accelerator actuation relationship when the running condition detection section has determined that the reaction force generating section is in an operable state.

12. The vehicle headway maintenance assist system according to claim 1, wherein the running condition detection section is further configured to determine whether the host vehicle and the preceding vehicle are in a prescribed positional relationship detected by the preceding vehicle detection section as the running condition that is used by the compensation section; andthe compensation section is further configured to change the first drive force/accelerator actuation relationship to the second drive force/accelerator actuation relationship when the running condition detection section has determined that the host vehicle and the preceding vehicle are in the prescribed positional relationship.

13. The vehicle headway maintenance assist system according to claim 1, wherein the running condition detection section is further configured to detect at least one of a vehicle speed, a path of the preceding vehicle, and a relative speed between the host vehicle and the preceding vehicle as a detected condition that is used by the compensation section to return to the first drive force/accelerator actuation relationship from the second drive force/accelerator actuation relationship; andthe drive source control section is configured to change a return rate of change of the target drive force when the compensation section returns to the first drive force/accelerator actuation relationship.

14. The vehicle headway maintenance assist system according to claim 1, wherein the drive source control section is configured to set a return rate of change of the target drive force when the compensation section returns to the first drive force/accelerator actuation relationship from the second drive force/accelerator actuation relationship, with the return rate of change of the target drive force being less than a compensating rate of change of the target drive force that occurred when the compensation section changed the first drive force/accelerator actuation relationship to the second drive force/accelerator actuation relationship.

15. A vehicle headway maintenance assist system comprising: preceding vehicle detection means for detecting a headway distance between a host vehicle and a preceding vehicle;accelerator actuation amount detection means for detecting an accelerator actuation amount of an accelerator of the host vehicle;accelerator actuation reaction force calculation means for calculating a reaction force to be generated in the accelerator based on the headway distance that was detected;actuation reaction force generation means for generating the reaction force that was calculated in the accelerator;running condition detecting means for detecting a running condition of the host vehicle;driving force determination means for determining a target driving force of the host vehicle in accordance with the accelerator actuation amount that was detected;drive source control means for controlling an output of a drive source towards the driving force determined by the driving force determination section; andcompensation means for increasing a driver awareness of the reaction force generated in the accelerator by changing from a first drive force/accelerator actuation relationship between the target drive force that was determined and the accelerator actuation amount that was detected to a second drive force/accelerator actuation relationship based on the running condition detected by the running condition detection section.

16. A vehicle headway maintenance assistance method comprising: detecting a running condition of a host vehicle and an accelerator actuation amount of an accelerator of the host vehicle;changing a first drive force/accelerator actuation relationship between a target drive force of the host vehicle and the accelerator actuation amount that was detected to a second drive force/accelerator actuation relationship based on the running condition that was detected;controlling an output of a drive source to approach the target drive force based on the accelerator actuation amount that was detected using one of the first and second drive force/accelerator actuation relationships depending upon the running condition that was detected;detecting a headway distance between the host vehicle and the preceding vehicle;computing an actuation reaction force to be generated in the accelerator based on the detected headway distance; andgenerating the calculated actuation reaction force in the accelerator.