VEHICLE HEADWAY MAINTENANCE ASSIST SYSTEM AND METHOD

Abstract

A vehicle headway maintenance assist system is configured to perform a haptic notification control of an accelerator to prompt the driver to release the accelerator when the accelerator is being operated and to perform a deceleration control of the vehicle based on headway distance when the accelerator is being operated as long as the headway distance from a preceding vehicle is less than a prescribed headway distance threshold.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

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

FIG. 1 is a schematic diagram of a vehicle 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 transient term L*a of the headway distance threshold in the headway maintenance assist system of the first embodiment of the present invention;

FIG. 4 is a flowchart showing the processing steps of a process for controlling the reaction force that is imparted to the accelerator pedal in the headway maintenance assist system of the first embodiment;

FIG. 5 is a flowchart showing the processing steps of a process for performing brake force control;

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

FIG. 7 is a flowchart showing the processing executed by the headway maintenance assist system in accordance with a second embodiment of the present invention;

FIG. 8 is a flowchart showing the processing executed for calculating the first headway distance threshold L*1 in the headway maintenance assist system of the second embodiment of the present invention;

FIG. 9 is a flowchart showing the processing executed for calculating the second headway distance threshold L*2 in the headway maintenance assist system of the second embodiment of the present invention

FIG. 10 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 second embodiment;

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 the headway distance threshold L* when the driver ceases to operate (depress) the accelerator pedal; and

FIG. 13 is a diagram showing the relationship between the relative speed Vr and the gain Kr1.

Claims

1. A vehicle headway maintenance assist system comprising: a headway distance detection section configured to detect a headway distance between a host vehicle and a preceding vehicle;an accelerator actuation detection section configured to detect actuation of an accelerator of the host vehicle;a deceleration control section configured to perform deceleration control of the host vehicle based on the headway distance when the accelerator is detected not as being operated while the headway distance detected by the headway distance detection section is less than a prescribed headway distance threshold; anda reaction force control section configured to control a reaction force imparted to the accelerator when the accelerator actuation detection section detects actuation of the accelerator while the headway distance detected by the headway distance detection section is less than the prescribed headway distance threshold.

2. The vehicle headway maintenance assist system according to claim 1, wherein the deceleration control section is further configured to perform the deceleration control when the accelerator actuation detection section detects that the accelerator is not operated while the headway distance detected by the headway distance detection section is less than the prescribed headway distance threshold after the reaction force has been applied to the accelerator by the reaction force control section.

3. The vehicle headway maintenance assist system according to claim 1, further comprising a headway distance threshold setting section configured to set the prescribed headway distance threshold based on a steady-state term that is computed irrespective of whether the preceding vehicle is decelerating and a transient term that is computed when the preceding vehicle is decelerating.

4. The vehicle headway maintenance assist system according to claim 3, further comprising a vehicle speed detection section configured to detect at least one of a host vehicle speed, a preceding vehicle speed and a relative speed between the host vehicle and the preceding vehicle; andthe headway distance threshold setting section being configured to calculate the steady-state term based on at least one of the host vehicle speed, the preceding vehicle speed and the relative speed.

5. The vehicle headway maintenance assist system according to claim 3, further comprising a relative speed detection section configured to detect a relative speed between the host vehicle and the preceding vehicle; andthe headway distance threshold setting section being configured to calculate the transient term by subtracting the steady-state term from the headway distance to obtain a resulting distance when the preceding vehicle begins to decelerate and then dividing the resulting distance by the relative speed.

6. The vehicle headway maintenance assist system according to claim 3, wherein the headway distance threshold setting section is configured to set the prescribed headway distance threshold by adding the steady-state term and the transient term.

7. The vehicle headway maintenance assist system according to claim 3, wherein the headway distance threshold setting section updates the value of the transient term in a case in which the headway distance detected by the headway distance detection section is greater than the prescribed headway distance threshold.

8. The vehicle headway maintenance assist system according to claim 1, wherein the headway distance threshold setting section sets a primary headway distance threshold for a primary deceleration control based on the headway distance detected by the headway distance detection section when the accelerator actuation detection section has detected that the accelerator has gone from being operated to not being operated, the primary headway distance threshold being greater than the prescribed headway distance threshold; andthe deceleration control section is further configured to control deceleration of the host vehicle when the headway distance detected by the headway distance detection section is less than the primary headway distance threshold for the primary deceleration control set by the headway distance threshold setting unit.

9. The vehicle headway maintenance assist system according to claim 8, wherein the headway distance threshold setting section is further configured to set the headway distance detected by the headway distance detection section when the accelerator actuation detection section has detected that the accelerator has gone from being operated to not being operated as the primary headway distance threshold for the primary deceleration control.

10. The vehicle headway maintenance assist system according to claim 8, wherein the headway distance threshold setting section is further configured to set the primary headway distance threshold based on a steady-state term calculated independently of a running condition of the host vehicle and a transient term depending on the running condition of the host vehicle.

11. The vehicle headway maintenance assist system according to claim 10, wherein the headway distance threshold setting section is further configured to set the primary headway distance threshold by adding the steady-state term and the transient term.

12. The vehicle headway maintenance assist system according to claim 10, wherein the headway distance threshold setting section is further configured to calculate the transient term based on a relative speed between the host vehicle and the preceding vehicle.

13. The vehicle headway maintenance assist system according to claim 8, further comprising a target deceleration rate setting section configured to calculate a secondary target deceleration rate of a secondary deceleration control based on the headway distance detected by the headway distance detection section and the prescribed headway distance threshold;calculate a primary target deceleration rate of the primary deceleration control based on the headway distance detected by the headway distance detection section and the primary headway distance threshold; andset a final target deceleration rate that is equal to whichever one of the primary and secondary deceleration rates is greater,the deceleration control section being configured to control the deceleration of the host vehicle based on the final target deceleration rate set by the target deceleration rate setting section.

14. The vehicle headway maintenance assist system according to claim 13, further comprising a target deceleration rate restricting section configured to restrict an upper limit of a rate of change of the primary target deceleration rate to a level below an upper limit of a rate of change of the secondary target deceleration rate.

15. The vehicle headway maintenance assist system according to claim 13, further comprising a target deceleration rate restricting section configured to restrict an upper limit of the primary target deceleration rate to a level below an upper limit of the secondary target deceleration rate.

16. A vehicle headway maintenance assist system comprising: headway distance detection means for detecting a headway distance between a host vehicle and a preceding vehicle;accelerator actuation detection means for detecting actuation of an accelerator of the host vehicle;deceleration control means for performing deceleration control of the host vehicle based on the headway distance when the accelerator is detected as not being operated while the headway distance detected by the headway distance means remains less than a prescribed headway distance threshold; andreaction force control means for controlling a reaction force imparted to the accelerator when the accelerator is being actuated while the headway distance detected by the headway distance means remains less than the prescribed headway distance threshold.

17. A vehicle headway maintenance assist system comprising: a headway distance detection section configured to detect a headway distance between a host vehicle and a preceding vehicle;an accelerator actuation detection section configured to detect actuation of an accelerator of the host vehicle;a deceleration control section configured to perform deceleration control of the host vehicle based on the headway distance when the accelerator is detected not as being operated while the headway distance detected by the headway distance detection section is less than a prescribed headway distance threshold; anda haptic notification control section configured to control a haptic notification imparted to the accelerator when the accelerator actuation detection section detects actuation of the accelerator while the headway distance detected by the headway distance detection section is less than the prescribed headway distance threshold.

18. A vehicle headway maintenance assistance method comprising: detecting a headway distance between a host vehicle and a preceding vehicle; andcontrolling deceleration of a host vehicle based on the headway distance that was detected when an accelerator is not being operated; andcontrolling a reaction force imparted to the accelerator when the accelerator is being actuated while the headway distance is less than a prescribed headway distance threshold.