Vehicle spacing control system

• US 6,434,471 B1
• Filed: 06/22/2000
• Issued: 08/13/2002
• Est. Priority Date: 06/23/1999
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Tange, Satoshi, Egawa, Kenichi, Higashimata, Akira, Asada, Tetsuya
• Primary Examiner(s): Nguyen, Tan
• Assistant Examiner(s): Tran, Dalena
• Application Number:
  US09/598,468
• Time in Patent Office: 782 Days
• Field of Search: 701/96, 701/93, 701/300, 701/36, 701/301, 340/903, 340/436, 340/435, 340/438, 342/70, 342/71
• US Class Current: 701/96
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/184 with wheel brakes
• CPC Class Codes: B60W 2050/0026 Lookup tables or parameter maps
• CPC Class Codes: B60W 2510/0657 Engine torque
• CPC Class Codes: B60W 2510/182 Brake pressure, e.g. of fluid or between pad and disc
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2540/215 Selection or confirmation of options
• CPC Class Codes: B60W 2554/801 Lateral distance
• CPC Class Codes: B60W 2754/30 Longitudinal distance
• CPC Class Codes: B60W 30/16 Control of distance between vehicles, e.g. keeping a distance to preceding vehicle
• CPC Class Codes: B60W 50/085 Changing the parameters of the control units, e.g. changing limit values, working points by control input
• CPC Class Codes: G08G 1/166 for active traffic, e.g. moving vehicles, pedestrians, bikes

Abstract

When a vehicle-to-vehicle time gap is changed from a first level to a second level with a selector switch, a controller determines a desired time gap so that the desired time gap varies from the first level to the second level at such a gradual rate as to prevent an abrupt change in the vehicle speed. The controller further determines a desired vehicle spacing from the controlled vehicle to a preceding vehicle in accordance with the desired time gap and a sensed vehicle speed, and controls the driving force and braking force of the controlled vehicle so as to bring the actual vehicle spacing closer to the desired vehicle spacing.

Claims

1. A vehicle spacing control apparatus comprising:

a vehicle spacing sensor sensing an actual vehicle spacing;

a vehicle speed sensor sensing an actual vehicle speed;

a selector changing a selected vehicle-to-vehicle time gap among a plurality of discrete values; and

a controller

determining a desired vehicle-to-vehicle time gap so that the desired time gap varies at a predetermined rate in response to a change in the selected time gap, the predetermined rate being a predetermined amount of change per unit time,

determining a desired vehicle spacing in accordance with the desired time gap and the actual vehicle speed, and

controlling at least one of a driving force and a braking force of a controlled vehicle so as to bring the actual vehicle spacing closer to the desired vehicle spacing.

2. The vehicle spacing control apparatus as claimed in claim 1, wherein the controller determines the desired time gap so that a time rate of change of the desired time gap is higher when the desired time gap is to be decreased than when the desired time gap is to be increased.

3. The vehicle spacing control apparatus as claimed in claim 1, wherein, when the desired time gap is decreased from a higher value to a lower value, the controller changes a time rate of change of the desired time gap midway during a transition of the desired time gap from the higher value to the lower value.

4. The vehicle spacing control apparatus as claimed in claim 1, wherein the controller has a predetermined map for determining the desired vehicle spacing from the time gap and the vehicle speed, and determines a value of the desired vehicle spacing corresponding to values of the desired time gap and the actual vehicle speed by look up from the map.

5. The vehicle spacing control apparatus as claimed in claim 1, wherein the vehicle spacing control apparatus is mounted on the controlled vehicle, and the selector is a device to be operated by a driver of the controlled vehicle to increase or decrease the desired vehicle spacing.

6. The vehicle spacing control apparatus as claimed in claim 5, wherein the vehicle spacing control apparatus further comprises an actuator for decelerating the controlled vehicle and an actuator for accelerating the controlled vehicle;

and

the controller controls the actuators so as to bring the actual vehicle spacing closer to the desired vehicle spacing.

7. A vehicle spacing control apparatus comprising:

a vehicle interval sensor sensing an actual vehicle-to-vehicle interval from a controlled vehicle to a preceding vehicle;

a selector changing a selected vehicle-to-vehicle interval among a plurality of discrete values; and

a controller

determining a desired vehicle-to-vehicle interval so that the desired vehicle-to-vehicle interval varies at a predetermined rate when the selected interval is changed, the predetermined rate being a predetermined amount of change per unit time, and

controlling a longitudinal force of a controlled vehicle so as to bring the actual vehicle-to-vehicle interval closer to the desired vehicle-to-vehicle interval.

8. The vehicle spacing control apparatus as claimed in claim 7, wherein, the controller determines a modified vehicle-to-vehicle interval so that, when the selected vehicle-to-vehicle interval is changed from a first interval value to a second interval value, the modified interval varies at a predetermined time rate of change from the first interval value to the second interval value, and the controller further determines the desired vehicle-to-vehicle interval from the modified interval.

9. The vehicle spacing control apparatus as claimed in claim 8, wherein the time rate of change of the modified interval is set equal to a predetermined constant rate value both when the selected interval is decreased, and when the selected interval is increased.

10. The vehicle spacing control apparatus as claimed in claim 8, wherein the time rate of change of the modified interval is set equal to a higher rate value when the selected interval is decreased, and set equal to a lower rate value smaller than the higher rate value when the selected interval is increased.

11. The vehicle spacing control apparatus as claimed in claim 8, wherein, when the selected interval is changed from a greater interval value to a smaller interval value smaller than the greater interval value, the time rate of change of the modified interval is set equal to a smaller rate value during a first period from a first instant at which the selected interval is changed from the greater interval value to the smaller interval value, to a second instant, and set equal to a greater rate value greater than the smaller rate value during a second period from the second instant to a third instant at which the modified interval becomes equal to the smaller interval value.

12. The vehicle spacing control apparatus as claimed in claim 7, wherein the actual interval is a spacing between the controlled vehicle to a preceding vehicle, the selected interval is a selected spacing, and the desired interval is a desired spacing from the controlled vehicle to a preceding vehicle.

13. The vehicle spacing control apparatus as claimed in claim 10, wherein the control apparatus further comprises a vehicle speed sensor sensing an actual vehicle speed, and the controller determines a modified interval by modifying the selected interval with the actual vehicle speed, and further determines the desired interval so that the desired interval follows a change in the modified interval at the predetermined rate.

14. The vehicle spacing control apparatus as claimed in claim 13, wherein the controller has a predetermined map for determining the modified interval from the selected interval and the actual vehicle speed, and determines a value of the modified interval corresponding to values of the selected interval and the actual vehicle speed by look up from the map.

15. The vehicle spacing control apparatus as claimed in claim 7, wherein the actual interval is a spatial interval between the controlled vehicle to a preceding vehicle, the selected interval is a selected time interval between the controlled vehicle and the preceding vehicle, and the desired interval is a desired spatial interval from the controlled vehicle to a preceding vehicle.

16. The vehicle spacing control apparatus as claimed in claim 7, wherein the vehicle spacing control apparatus is mounted on the controlled vehicle, and the selector is a device to be operated by a driver of the controlled vehicle to increase or decrease the desired vehicle spacing.

17. A vehicle spacing control process comprising:

ascertaining a sensed actual vehicle-to-vehicle interval from a controlled vehicle to a preceding vehicle;

ascertaining a selected vehicle-to-vehicle interval selected among a plurality of discrete values;

determining a desired vehicle-to-vehicle interval so that the desired vehicle-to-vehicle interval varies at a predetermined rate when the selected interval is changed, the predetermined rate being a predetermined amount of change per unit time; and

controlling a longitudinal force of a controlled vehicle so as to bring the actual vehicle-to-vehicle interval closer to the desired vehicle-to-vehicle interval.

18. A vehicle spacing control apparatus comprising:

means for ascertaining a sense actual vehicle-to-vehicle interval from a controlled vehicle to a preceding vehicle;

means for ascertaining a change from a first select position to a second select position in a selector for determining a selected vehicle-to-vehicle interval;

means for responding to the change from the first select position to the second select position in the selector by varying a desired vehicle-to-vehicle interval at a predetermine rate from a first select value corresponding to the first select position to a second select value corresponding to the second select position, the predetermined rate being a predetermined amount of change per unit time; and

means for controlling a longitudinal force of a controlled vehicle so as to bring the actual vehicle-to-vehicle interval closer to the desired vehicle-to-vehicle interval.