System and methods utilizing slope of target speed for cooperative speed for cooperative speed control system

• US 20060229792A1
• Filed: 03/31/2005
• Published: 10/12/2006
• Est. Priority Date: 03/31/2005
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Technical Center North America Incorporated (Nissan Motor Co., Ltd.)
• Inventors: Tsuda, Hiroshi, Kawazoe, Hiroshi
• Granted Patent: US 7,627,413 B2
• Time in Patent Office: Days
• US Class Current: 701/93
• CPC Class Codes: B60W 2552/40 Coefficient of friction
• CPC Class Codes: B60W 2556/50 of positioning data, e.g. GPS [Global Positioning System] data
• CPC Class Codes: B60W 30/16 Control of distance between vehicles, e.g. keeping a distance to preceding vehicle
• CPC Class Codes: B60W 40/04 Traffic conditions

Abstract

A device for automatically controlling vehicle speed, including a processor, wherein the processor includes logic to determine a vehicle acceleration rate value, wherein the processor is configured to receive at least a first signal indicative of a first local required speed, a second signal indicative of a second local required speed received after the first signal, a third signal indicative of a value of a current vehicle speed, and information that enables the processor to determine the vehicle acceleration rate value, wherein the processor further includes logic to automatically determine a new set vehicle speed based at least on the first local required speed, the second local required speed, the current vehicle speed, and the determined vehicle acceleration rate value, and automatically initiate output of a signal to a vehicle speed controller to change vehicle speed to the new set vehicle speed.

Claims

1. A device adapted to automatically control vehicle speed, comprising:

a processor, wherein the processor includes logic to automatically determine a vehicle acceleration rate value;

wherein

the processor is adapted to;

receive at least a first signal indicative of a first local required speed, a second signal indicative of a second local required, a third signal indicative of a value of a current vehicle speed, and information that enables the processor to determine the vehicle acceleration rate value;

wherein

the processor further includes logic to;

automatically determine a new set vehicle speed based at least on the first local required speed, the second local required speed, the current vehicle speed, and the determined vehicle acceleration rate value; and

automatically initiate output of a signal to a vehicle speed controller to change vehicle speed to the new set vehicle speed.

2. The device according to claim 1, wherein the received information that enables the processor to determine a vehicle acceleration rate value is a value for the vehicle acceleration rate value.

3. The device according to claim 1, wherein the received information that enables the processor to determine a vehicle acceleration rate value relates to a current vehicle component status, and wherein the determined vehicle acceleration rate value is an effective constant.

4. The device according to claim 3, further comprising a device adapted to automatically change the vehicle speed to the new set vehicle speed based on the determined vehicle acceleration rate value.

5. The device according to claim 3, wherein the processor further includes logic to:

automatically determine a value for a distance L, wherein the distance L is indicative of a distance between a current vehicle position and a position where the first local required speed will change to the second local required speed; and

automatically determine a value for a time T which is equivalent to a value obtained by dividing the value for the distance L by the value for the current vehicle speed.

6. The device according to claim 5, wherein the processor further includes logic to:

automatically determine a value for a time Δ

t which is equivalent to a value obtained by;

subtracting the value of the current vehicle speed from the new set vehicle speed to obtain a resulting value, and dividing the resulting value by the determined vehicle acceleration rate value; and

automatically initiate output of the signal to the vehicle speed controller to change the vehicle speed to the new set vehicle speed if the value of the times T and Δ

t are substantially equal to each other.

7. The device according to claim 6, wherein the logic to automatically initiate output of the signal to the vehicle speed controller to change the vehicle speed to the new set vehicle speed if the value of the time T and Δ

t are substantially equal to each other includes logic to automatically initiate output of a signal to the vehicle speed controller to at least one of;

(a) gradually reduce the speed to the new set vehicle speed substantially in accordance with the determined vehicle acceleration rate value; and

(b) gradually increase the speed to the new set vehicle speed substantially in accordance with the determined vehicle acceleration rate value.

8. The device according to claim 1, wherein the processor is adapted to receive information that enables the processor to determine whether the vehicle is approaching a caution zone, and wherein the processor further includes logic to:

automatically determine whether the current vehicle speed is greater than the new set vehicle speed;

automatically determine the vehicle acceleration rate value based on predetermined values of the vehicle acceleration rate value, wherein the predetermined values of the vehicle acceleration rate value vary with respect to at least a value which is indicative of a distance between a caution zone and a location where the first required speed changes to the second required speed; and

if at least the current vehicle speed is determined to be greater than the new set vehicle speed, and if at least the vehicle is determined to be approaching a caution zone, automatically initiate output of a signal to the vehicle speed controller to reduce vehicle speed to the new set vehicle speed.

9. The device according to claim 8, wherein the vehicle speed controller is adapted to reduce vehicle speed based on the determined vehicle acceleration rate value.

10. The device according to claim 1, wherein the processor is adapted to receive information that enables the processor to determine whether the vehicle is approaching a caution zone, and wherein the processor further includes logic to:

automatically determine whether the current vehicle speed is greater than the new set vehicle speed;

automatically determine the vehicle acceleration rate value based on predetermined values of the vehicle acceleration rate value, wherein the predetermined values of the vehicle acceleration rate value vary with respect to at least a value which is indicative of a distance between a caution zone and a location where the first required speed changes to the second required speed;

automatically determine a value for a time Δ

t based on the determined vehicle acceleration rate value;

automatically determine whether the time Δ

t substantially equals a time for the vehicle to reach the location where the first required speed changes to the second required speed at the current vehicle speed; and

if at least the current vehicle speed is determined to be greater than the new set vehicle speed, and if at least the vehicle is determined to be approaching a caution zone, and if at least the time Δ

t substantially equals a time for the vehicle to reach the location where the first required speed changes to the second required speed at the current vehicle speed, automatically initiate output of a signal to the vehicle speed controller to reduce vehicle speed to the new set vehicle speed.

11. The device according to claim 1, wherein the processor is adapted to receive information that enables the processor to determine whether the vehicle is approaching a caution zone, wherein the processor is adapted to receive information related to at least one of (i) a type of caution zone that the vehicle is approaching and (ii) a condition of the caution zone that the vehicle is approaching, and wherein the processor further includes logic to:

automatically determine whether the current vehicle speed is greater than the new set vehicle speed;

automatically determine a value of the vehicle acceleration rate value based on predetermined values of the vehicle acceleration rate value, wherein the predetermined values of the vehicle acceleration rate value vary with respect to at least one of the type of caution zone that the vehicle is approaching and the condition of the caution zone that the vehicle is approaching and a value which is indicative of a distance between a caution zone and a location where the first required speed changes to the second required speed; and

if at least the current vehicle speed is determined to be greater than the new set vehicle speed, and if at least the vehicle is determined to be approaching a caution zone, automatically initiate output of a signal to the vehicle speed controller to reduce vehicle speed to the new set vehicle speed.

12. The device according to claim 1, wherein the processor is adapted to receive information that enables the processor to determine whether the vehicle is approaching a caution zone, wherein the processor is adapted to receive information related to at least one of (i) a type of caution zone that the vehicle is approaching and (ii) a condition of the caution zone that the vehicle is approaching, and wherein the processor further includes logic to:

automatically determine whether the current vehicle speed is greater than the new set vehicle speed;

automatically determine a value of the vehicle acceleration rate value based on predetermined values of the vehicle acceleration rate value, wherein the predetermined values of the vehicle acceleration rate value vary with respect to at least one of the type of caution zone that the vehicle is approaching and the condition of the caution zone that the vehicle is approaching and a value which is indicative of a distance between a caution zone and a location where the first required speed changes to the second required speed;

automatically determine a value for a time Δ

t based on the determined vehicle acceleration rate value;

automatically determine whether the time Δ

t substantially equals a time for the vehicle to reach the location where the first required speed changes to the second required speed at the current vehicle speed; and

if at least the current vehicle speed is determined to be greater than the new set vehicle speed, and if at least the vehicle is determined to be approaching a caution zone, and if at least the time Δ

t substantially equals a time for the vehicle to reach the location where the first required speed changes to the second required speed at the current vehicle speed, automatically initiate output of a signal to the vehicle speed controller to reduce vehicle speed to the new set vehicle speed.

13. The device according to claim 1, wherein the processor is adapted to receive information that enables the processor to determine whether the vehicle is approaching a caution zone, wherein the processor is adapted to receive information that enables the processor to determine whether the vehicle is approaching a red traffic light, and wherein the processor further includes logic to:

automatically determine a value for a distance L, wherein the distance L is the distance between a current vehicle position and a position where the first local required speed will change to the second local required speed;

automatically determine a value for a time T which is equivalent to a value obtained by dividing the value for the distance L by the value indicative of the current vehicle speed;

automatically determine whether the current vehicle speed is greater than the new set vehicle speed; and

if the current vehicle speed is determined to be greater than the new set vehicle speed and the vehicle is determined to be approaching a red traffic light;

automatically determine a value for a time Δ

t based on the determined vehicle acceleration rate value, wherein the determined vehicle acceleration rate value is predetermined for vehicle approach of a red traffic light; and

automatically determine whether the time T and the time Δ

t are substantially equal to each other; and

if the time T and the time Δ

t are substantially equal to each other, automatically initiate output of a signal to the vehicle speed controller to reduce vehicle speed to the new set vehicle speed.

14. The device according to claim 1, wherein the processor further includes logic to:

automatically determine a value for a distance which is indicative of a distance between a caution zone and a location where the first required speed changes to the second required speed and use this determined value to determine the vehicle acceleration rate value; and

use the determined vehicle acceleration rate value to control approach speed to the caution zone.

15. The device according to claim 1, wherein the processor is adapted to receive information that enables the processor to determine that the vehicle is approaching a red traffic light, and wherein the processor further includes logic to:

automatically determine a value for a distance L, wherein the distance L is indicative of the distance between a current vehicle position and a position where the first local required speed will change to the second local required speed;

automatically determine a value for a time T which is equivalent to a value obtained by dividing the value for the distance L by the value indicative of the current vehicle speed;

automatically determine whether the current vehicle speed is greater than the new set vehicle speed;

automatically determine a value for a distance Lf which is indicative of a distance between a caution zone and a location where the first required speed changes to the second required speed;

automatically determine a value for the vehicle acceleration rate value based on a predetermined relationship between the vehicle acceleration rate value and Lf;

automatically determine a time Δ

t which is indicative of a value obtained by subtracting the value of the current vehicle speed from the new set vehicle speed to obtain a resulting value, and dividing the resulting value by the value of the vehicle acceleration rate value;

automatically determine whether the time T and the time Δ

t are substantially equal to each other; and

if at least the current vehicle speed has been determined to be greater than the new set vehicle speed, and if at least the processor has not determined that the vehicle is approaching a red traffic light and if at least the time T and the time Δ

t are substantially equal to each other, automatically initiate output of a signal to the vehicle speed controller to reduce the speed to the new set vehicle speed substantially in accordance with the determined vehicle acceleration rate value.

16. The device according to claim 15, wherein, in the predetermined relationship, the vehicle acceleration rate values increase as the value of Lf increases to a first value of Lf and the vehicle acceleration rate values are constant for values of Lf greater than the first value of Lf.

17. The device according to claim 1, wherein the processor is adapted to receive information that enables the processor to determine when the vehicle is traveling away from a caution zone, and wherein the processor further includes logic to:

automatically determine whether the current vehicle speed is less than the new set vehicle speed;

automatically determine the vehicle acceleration rate value based on predetermined values of the vehicle acceleration rate value, wherein the predetermined values of vehicle acceleration rate value vary with respect to at least a value which is indicative of a distance between a caution zone and a location where the first required speed changes to the second required speed;

automatically determine a time Δ

t which is indicative of a value obtained by subtracting the value of the current vehicle speed from the new set vehicle speed to obtain a resulting value, and dividing the resulting value by the value of the vehicle acceleration rate value;

automatically determine whether the time Δ

t substantially equals a time for the vehicle to reach the location where the first required speed changes to the second required speed at the current vehicle speed;

if at least the current vehicle speed is determined to be less than the new set vehicle speed, if at least the vehicle is determined to be traveling away from a caution zone, and if at least the time Δ

t substantially equals a time for the vehicle to reach the location where the first required speed changes to the second required speed at the current vehicle speed, automatically initiate output of a signal to the vehicle speed controller to increase vehicle speed to the new set vehicle speed.

18. The device according to claim 1, wherein the processor further includes logic to:

automatically determine a value for a distance L, wherein the distance L is the distance between a current vehicle position and a position where the first local required speed will change to the second local required speed;

automatically determine a value for a time T which is equivalent to a value obtained by dividing the value for the distance L by the value indicative of the current vehicle speed;

automatically determine whether the current vehicle speed is less than the new set vehicle speed;

automatically determine a value for a distance Lr which is indicative of a distance between a caution zone and a location where the first required speed changes to the second required speed;

automatically determine a value for a time Δ

t based on a predetermined relationship between Δ

t and Lr;

automatically determine a value for an acceleration rate, which is indicative of a value obtained by subtracting the value of the current vehicle speed from the new set vehicle speed to obtain a resulting value, and dividing the resulting value by the value of the time Δ

t;

automatically determine whether the time T and the time Δ

t are substantially equal to each other; and

if at least the time T and the time Δ

t are substantially equal to each other, and if at least the current vehicle speed has been determined to be less than the new set vehicle speed, automatically initiate output of a signal to the vehicle speed controller to increase the speed to the new set vehicle speed substantially in accordance with the determined vehicle acceleration rate value.

19. The device according to claim 16, wherein, in the predetermined relationship, the vehicle acceleration rate values decreases as the value of Lr increases to a first value of Lr and the vehicle acceleration rate values are constant for values of Lr greater than the first value of Lr.

20. The device according to claim 1, wherein the processor further includes logic to:

automatically analyze received information indicative of a local traffic density and use this analysis to determine the vehicle acceleration rate value; and

use the determined vehicle acceleration rate value to control approach speed to a caution zone.

21. The device according to claim 1, wherein the processor further includes logic to:

automatically determine a value for a distance L, wherein the distance L is the distance between a current vehicle position and a position where the first local required speed will change to the second local required speed;

automatically determine a value for a time T which is equivalent to a value obtained by dividing the value for the distance L by the value indicative of the current vehicle speed;

automatically determine whether the current vehicle speed is greater than the new set vehicle speed;

automatically receive information indicative of a local traffic density;

automatically determine a value for the vehicle acceleration rate value based on a predetermined relationship between the vehicle acceleration rate value and traffic density;

automatically determine a time Δ

t which is indicative of a value obtained by subtracting the current vehicle speed from the new set vehicle speed to obtain a resulting value, and dividing the resulting value by the value of the vehicle acceleration rate value;

automatically determine whether the time T and the time Δ

t are substantially equal to each other; and

if at least the time T and the time Δ

t are substantially equal to each other, and if at least the current vehicle speed has been determined to be greater than the new set vehicle speed, automatically initiate output of a signal to the vehicle speed controller to reduce the speed to the new set vehicle speed substantially in accordance with the determined vehicle acceleration rate value.

22. The device according to claim 21, wherein in the predetermined relationship, the vehicle acceleration rate value is a first constant for a first traffic density range of values, and the vehicle acceleration rate value decreases from the first constant with increasing traffic density.

23. The device according to claim 1, wherein the processor further includes logic to:

automatically determine a value for a distance L, wherein the distance L is the distance between a current vehicle position and a position where the first local required speed will change to the second local required speed;

automatically determine a value for a time T which is equivalent to a value obtained by dividing the value for the distance L by the value indicative of the current vehicle speed;

automatically determine whether the current vehicle speed is less than the new set vehicle speed;

automatically receive information indicative of a local traffic density;

automatically determine a value for the vehicle acceleration rate value based on a predetermined relationship between the vehicle acceleration rate value and traffic density;

automatically determine a time Δ

t which is indicative of a value obtained by subtracting the current vehicle speed from the new set vehicle speed to obtain a resulting value, and dividing the resulting value by the value of the vehicle acceleration rate value;

automatically determine whether the time T and the time Δ

t are substantially equal to each other; and

if at least the time T and the time Δ

t are substantially equal to each other, and if at least the current vehicle speed has been determined to be less than the new set vehicle speed, automatically initiate output of a signal to the vehicle speed controller to increase the speed to the new set vehicle speed substantially in accordance with the determined vehicle acceleration rate value.

24. The device according to claim 23, wherein in the predetermined relationship, the vehicle acceleration rate value is a first constant for a first traffic density range of values, and the vehicle acceleration rate value increases from the first constant with increasing traffic density values.

25. The device according to claim 1, wherein the processor further includes logic to:

automatically analyze a fourth signal indicative of a local road surface coefficient of friction and use this analysis to determine the vehicle acceleration rate value; and

use the determined vehicle acceleration rate value to control approach speed to a caution zone.

26. The device according to claim 1, wherein the processor is adapted to receive a fourth signal indicative of a local road surface coefficient of friction, and wherein the processor further includes logic to:

automatically determine a value for a distance L, wherein the distance L is the distance between a current vehicle position and a position where the first local required speed will change to the second local required speed;

automatically determine a value for a time T which is equivalent to a value obtained by dividing the value for the distance L by the value indicative of the current vehicle speed;

automatically determine a value for the vehicle acceleration rate value based on a predetermined relationship between the vehicle acceleration rate value and a value indicative of a road surface coefficient of friction;

automatically determine a time Δ

t which is indicative of a value obtained by subtracting the current vehicle speed from the new set vehicle speed to obtain a resulting value, and dividing the resulting value by the value of the vehicle acceleration rate value;

automatically determine whether the time T and the time Δ

t are substantially equal to each other; and

if at least the time T and the time Δ

t are substantially equal to each other, automatically initiate output of a signal to the vehicle speed controller to reduce the speed to the new set vehicle speed substantially in accordance with the determined vehicle acceleration rate value.

27. The device according to claim 24, wherein in the predetermined relationship, the vehicle acceleration rate value is a first constant for a first range of values indicative of road surface coefficients of friction, the vehicle acceleration rate value decreases from the first constant in a range of decreasing road surface coefficients of friction between the first range and a second range of values related to road surface coefficient of friction, and the vehicle acceleration rate value is a second constant for the second range of values related to road surface coefficient of friction, the second constant being lower than the first constant.

28. The device according to claim 1, wherein the processor further includes logic to:

automatically analyze a fourth signal indicative of at least one of a driver'"'"'s desired deceleration rate and a driver'"'"'s desired acceleration rate and use this analysis to determine the vehicle acceleration rate value; and

use the determined vehicle acceleration rate value to control approach speed to a caution zone.

29. The device according to claim 1, wherein the processor is adapted to receive a fourth signal indicative of at least one of a driver'"'"'s desired deceleration rate and a driver'"'"'s desired acceleration rate, and wherein the processor further includes logic to:

automatically determine a value for a distance L, wherein the distance L is the distance between a current vehicle position and a position where the first local required speed will change to the second local required speed;

determine a value for a time T which is equivalent to a value obtained by dividing the value for the distance L by the value indicative of the current vehicle speed;

automatically determine whether the current vehicle speed is greater than the new set vehicle speed;

automatically determine a value for the vehicle acceleration rate value based on a predetermined relationship between the vehicle acceleration rate value and the driver'"'"'s desired deceleration rate;

automatically determine a time Δ

t which is indicative of a value obtained by subtracting the current vehicle speed from the new set vehicle speed to obtain a resulting value, and dividing the resulting value by the value of the vehicle acceleration rate value;

automatically determine whether the time T and the time Δ

t are substantially equal to each other; and

if at least the time T and the time Δ

t are substantially equal to each other, and if at least the current vehicle speed has been determined to be greater than the new set vehicle speed, automatically initiate output of a signal to the vehicle speed controller to reduce the speed to the new set vehicle speed substantially in accordance with the determined vehicle acceleration rate value.

30. The device according to claim 1, wherein the processor is adapted to receive a fourth signal indicative of at least one of a driver'"'"'s desired deceleration rate and a driver'"'"'s desired acceleration rate, and wherein the processor further includes logic to:

automatically determine a value for a distance L, wherein the distance L is the distance between a current vehicle position and a position where the first local required speed will change to the second local required speed;

automatically determine a value for a time T which is equivalent to a value obtained by dividing the value for the distance L by the value indicative of the current vehicle speed;

automatically determine whether the current vehicle speed is less than the new set vehicle speed;

automatically determine a value for the vehicle acceleration rate value based on a predetermined relationship between the vehicle acceleration rate value and the driver'"'"'s desired acceleration rates;

automatically determine a time Δ

t which is indicative of a value obtained by subtracting the current vehicle speed from the new set vehicle speed to obtain a resulting value, and dividing the resulting value by the value of the vehicle acceleration rate value;

determine whether the time T and the time Δ

t are substantially equal to each other; and

if the time T and the time Δ

t are substantially equal to each other, and if the current vehicle speed has been determined to be less than the new set vehicle speed, automatically initiate output of a signal to the vehicle speed controller to increase the speed to the new set vehicle speed substantially in accordance with the determined vehicle acceleration rate value.

31. A vehicle, comprising:

a vehicle body supporting a device according to claim 1.

32. A vehicle, comprising:

a vehicle body supporting a device according to claim 8.

33. A vehicle, comprising:

a vehicle body supporting a device according to claim 14.

34. A vehicle, comprising:

a vehicle body supporting a device according to claim 17.

35. A vehicle, comprising:

a vehicle body supporting a device according to claim 25.

36. A vehicle, comprising:

a vehicle body supporting a device according to claim 28.