Automatic speed control device for vehicle

• US 6,311,120 B1
• Filed: 01/07/1999
• Issued: 10/30/2001
• Est. Priority Date: 01/08/1998
• Status: Expired due to Term

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Asada, Tetsuya
• Primary Examiner(s): Nguyen, Tan
• Assistant Examiner(s): Tran, Dalena
• Application Number:
  US09/226,156
• Time in Patent Office: 1,027 Days
• Field of Search: 701/96, 701/41, 701/93, 701/300, 701/301, 340/903, 340/933, 340/435, 367/87, 367/99, 367/89, 367/118
• US Class Current: 701/96
• CPC Class Codes: B60K 31/0008 including means for detecting potential obstacles in vehicle path
• CPC Class Codes: B60W 2050/143 Alarm means
• CPC Class Codes: B60W 2520/14 Yaw
• CPC Class Codes: B60W 2540/18 Steering angle
• CPC Class Codes: B60W 2552/15 Road slope, i.e. the inclination of a road segment in the longitudinal direction
• CPC Class Codes: B60W 2754/30 Longitudinal distance
• CPC Class Codes: B60W 30/18145 Cornering

Abstract

An automatic speed control device for a vehicle includes a distance measuring sensor 3, a vehicle speed sensor 5 and a control unit 9 for controlling the vehicle speed. In the control unit 9, a target speed determining section 11 determines a target speed corresponding to a distance detected by the distance measuring sensor 3 and the vehicle speed detected by the vehicle speed sensor 5. A speed storing section 13 of the control unit 9 stores the detected vehicle speed as a set speed. A selecting section 15 of the control unit 9 selects a smaller speed of the target speed and the set speed. A speed control section 17 of the control unit 9 controls the vehicle speed so as to be the smaller speed selected by the selecting section 15. When losing the preceding vehicle, the speed control section 17 further controls the vehicle speed so as to maintain a present vehicle speed until the driver'"'"'s vehicle reaches a lost point where the preceding vehicle was lost.

Claims

1. An automatic speed control device for controlling a speed of a driver'"'"'s vehicle depending on an existence of a preceding vehicle traveling ahead of the driver'"'"'s vehicle, the automatic speed control device comprising:

a speed control section for controlling a vehicle speed of the driver'"'"'s vehicle so as to realize a predetermined distance between the driver'"'"'s vehicle and the preceding vehicle when there exists the preceding vehicle traveling ahead of the driver'"'"'s vehicle, the predetermined distance being established corresponding to both of the vehicle speed of the driver'"'"'s vehicle and a vehicle speed of the preceding vehicle in advance, and further controlling the driver'"'"'s vehicle to accelerate to a preset vehicle speed when the preceding vehicle is lost;

wherein, when losing track of the preceding vehicle, the speed control section at least controls the vehicle speed of the driver'"'"'s vehicle so as to maintain a vehicle speed of the driver'"'"'s vehicle at a time of losing the preceding vehicle at least until the driver'"'"'s vehicle arrives at a lost point where the preceding vehicle was lost.

2. An automatic speed control device for controlling a speed of a driver'"'"'s vehicle depending on an existence of a preceding vehicle ahead of the driver'"'"'s vehicle, the automatic speed control device comprising:

a distance measuring unit for measuring a distance between the driver'"'"'s vehicle and the preceding vehicle;

a speed detecting unit for detecting a vehicle speed of the driver'"'"'s vehicle;

a target speed determining unit for determining a target speed corresponding to the distance detected by the distance measuring unit and the vehicle speed detected by the speed detecting unit;

a speed storing section for storing the vehicle speed detected by the speed detecting unit as a set speed, in accordance with a manual operation performed by the driver;

a selecting section for selecting a smaller speed of the target speed determined by the target speed determining unit and the set speed stored by the speed storing unit; and

a speed control section for controlling the vehicle speed so as to be the smaller speed selected by the selecting unit;

wherein, when losing the preceding vehicle, the speed control unit further controls the vehicle speed so as to maintain a vehicle speed of the driver'"'"'s vehicle at a time of losing the preceding vehicle until the driver'"'"'s vehicle arrives at a lost point where the preceding vehicle was lost,

wherein, when losing the preceding vehicle while the selecting section selects the target speed, the speed control unit controls the vehicle speed so as to maintain the target speed until the driver'"'"'s vehicle arrives at the lost point, and furthermore, when still losing the preceding vehicle even after the driver'"'"'s vehicle has arrived at the lost point, the speed control unit further controls the vehicle speed so as to change the target speed to the set speed.

3. The automatic speed control device of claim 2, wherein, when the preceding vehicle cannot be detected by the distance measuring unit and when the lost point is included in a curve larger than a predetermined curve, the speed control section controls the vehicle speed so as to maintain a vehicle speed of the driver'"'"'s vehicle at a time of losing the preceding vehicle.

4. The automatic speed control device of claim 2, wherein, when the preceding vehicle cannot be detected by the distance measuring unit and when the lost point is contained in a straight load, the speed control section controls the vehicle speed so as to increase to the set speed stored in the speed storing section.

5. The automatic speed control device of claim 2, further comprising a steering angle detecting unit for detecting a steering angle of the driver'"'"'s vehicle, wherein, when it is judged on the basis of the steering angle of the driver'"'"'s vehicle that the driver'"'"'s vehicle is traveling in a regular curve represented by a steering angle more than a predetermined steering angle, the speed control section controls the vehicle speed so as to maintain a present vehicle speed.

6. The automatic speed control device of claim 2, wherein the speed control section controls the vehicle speed so as to maintain a present vehicle speed until the preceding vehicle is detected again by the distance measuring unit.

7. The automatic speed control device of claim 2, further comprising a steering angle detecting unit for detecting a steering angle of the driver'"'"'s vehicle, wherein, when it is judged on the basis of the steering angle of the driver'"'"'s vehicle that the driver'"'"'s vehicle travels in a curve larger than a predetermined curve and when no preceding vehicle travels in front of the driver'"'"'s vehicle, the speed control section controls the vehicle speed so as to increase to the set speed.

15. The automatic speed control device of claim 2, further comprising:

a distance measuring area judging section for judging which parts of a distance measuring area of the distance measuring unit the preceding vehicle is traveling, on the basis of the distance and the angle detected by the distance measuring unit,

wherein, when the preceding vehicle is lost in the farthest part of the distance measuring area, the speed control section further controls the vehicle speed so as to increase the set speed.

16. The automatic speed control device of claim 2, further comprising:

a distance measuring area judging section for judging which parts of a distance measuring area of the distance measuring unit the preceding vehicle is traveling, on the basis of the distance and the angle detected by the distance measuring unit,

wherein, when the preceding vehicle is lost in the nearest part of the distance measuring area, the speed control section further controls the vehicle speed so as to maintain the vehicle speed just before losing the preceding vehicle or decrease at a deceleration rate just before losing the preceding vehicle.

17. The automatic speed control device of claim 16, further comprising:

an informing unit for informing the driver that the distance measuring unit is in an inactivated condition.

8. An automatic speed control device for controlling a speed of a driver'"'"'s vehicle depending on an existence of a preceding vehicle traveling ahead of a driver'"'"'s vehicle, the automatic speed control device comprising:

a distance measuring unit for measuring a distance between the driver'"'"'s vehicle and the preceding vehicle and an angle of the preceding vehicle to the driver'"'"'s vehicle;

a speed detecting unit for detecting a vehicle speed of the driver'"'"'s vehicle;

a steering angle detecting unit for detecting a steering angle of the driver'"'"'s vehicle;

a slope change judging section for judging whether there is a predetermined slope change at a traveling point of the preceding vehicle, on the basis of an angle of the preceding vehicle;

a target speed determining section for determining a target speed corresponding to the distance detected by the distance measuring unit and the vehicle speed detected by the speed detecting unit;

a speed storing section for storing the vehicle speed detected by the speed detecting unit as a set speed;

a selecting section for selecting a smaller speed of the target speed determined by the target speed determining section and the set speed stored by the speed storing section; and

a speed control section for controlling the vehicle speed so as to be the smaller speed selected by the selecting section;

wherein, when the preceding vehicle is lost and it is judged that there exists the predetermined slope change in the vicinity of a lost point of losing the preceding vehicle by the slope change judging section, the speed control section further controls the vehicle speed so as to maintain a vehicle speed of the driver'"'"'s vehicle at a time of losing the preceding vehicle.

9. The automatic speed control device of claim 8, wherein, when the preceding vehicle is lost and when it is judged that there is no slope change in the lost point by the slope change judging section, the speed control section controls the,vehicle speed so as to increase to the set speed.

10. The automatic speed control device of claim 8, wherein, when the preceding vehicle is lost and it is judged that there exists the predetermined slope change in the vicinity of a lost point of losing the preceding vehicle by the slope change judging section, the speed control section further controls the vehicle speed so as to maintain the present vehicle speed as long as a predetermined distance.

11. The automatic speed control device of claim 10, wherein, when no preceding vehicle is detected even after the driver'"'"'s vehicle'"'"'s traveling the predetermined distance, the speed control section controls the vehicle speed so as to increase to the set speed.

12. The automatic speed control device of claim 8, further comprising:

a distance measuring area judging section for judging which parts of a distance measuring area of the distance measuring unit the preceding vehicle is traveling, on the basis of the distance and the angle detected by the distance measuring unit,

wherein, when the preceding vehicle is lost in a central part of the distance measuring area and it is judged that there exists the predetermined slope change in the vicinity of the lost point of losing the preceding vehicle, the speed control section further controls the vehicle speed so as to maintain the present vehicle speed.

13. The automatic speed control device of claim 8, further comprising:

a distance measuring area judging section for judging which parts of a distance measuring area of the distance measuring unit the preceding vehicle is traveling, on the basis of the distance and the angle detected by the distance measuring unit; and

an informing unit for informing the driver that the distance measuring unit is in an inactivated condition when the preceding vehicle is lost in a central part of the distance measuring area and it is judged that there is no slope change in the vicinity of the lost point of losing the preceding vehicle.

14. An automatic speed control device for controlling a speed of a driver'"'"'s vehicle depending on an existence of a preceding vehicle ahead of the driver'"'"'s vehicle, the automatic speed control device comprising:

a distance measuring unit for measuring a distance between the driver'"'"'s vehicle and the preceding vehicle;

a speed detecting unit for detecting a vehicle speed of the driver'"'"'s vehicle;

a target speed determining unit for determining a target speed corresponding to the distance detected by the distance measuring unit and the vehicle speed detected by the speed detecting unit;

a speed storing section for storing the vehicle speed detected by the speed detecting unit as a set speed, in accordance with a manual operation performed by the driver;

a selecting section for selecting a smaller speed of the target speed determined by the target speed determining unit and the set speed stored by the speed storing unit; and

a speed control section for controlling the vehicle speed so as to be the smaller speed selected by the selecting unit;

wherein, when losing the preceding vehicle, the speed control unit further controls the vehicle speed so as to maintain a vehicle speed of the driver'"'"'s vehicle at a time of losing the preceding vehicle until the driver'"'"'s vehicle arrives at a lost point where the preceding vehicle was lost,

wherein, when the preceding vehicle cannot be detected by the distance measuring unit and when the lost point is included in a curve larger than a predetermined curve, the speed control section controls the vehicle speed as so t o maintain the vehicle speed at the driver'"'"'s vehicle at a time of losing the preceding vehicle,

the automatic speed control device further comprising;

a distance measuring area judging section for judging which parts of a distance measuring area of the distance measuring unit the preceding vehicle is traveling, on the basis of the distance and the angle detected by the distance measuring unit; and

a motion vector detecting section for detecting a motion vector representing that the preceding vehicle moves laterally,

wherein, when the preceding vehicle is lost in an outside part of the distance measuring area and when the motion vector before losing the preceding vehicle directs outward, the speed control section controls the vehicle speed so as to either maintain the present vehicle speed or increase to the set speed; and

wherein, when the preceding vehicle is lost in an outside part of the distance measuring area and when the motion vector before losing the preceding vehicle directs inward, the speed control section selects any one of the control methods of;

maintaining the present vehicle speed;

increasing the present vehicle speed to the set speed; and

maintaining the present vehicle speed as long as a predetermined distance.