Vehicle collision avoidance and warning

• US 20080183360A1
• Filed: 05/07/2007
• Published: 07/31/2008
• Est. Priority Date: 05/08/2006
• Status: Abandoned Application

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Antonsson, Erik K., Zhang, Yizhen
• Application Number:
  US11/800,962
• Publication Number:
  US 20080183360A1
• Time in Patent Office: Days
• US Class Current: 701/70
• CPC Class Codes: B60W 2050/143 Alarm means
• CPC Class Codes: B60W 2420/408 Radar; Laser, e.g. lidar
• CPC Class Codes: B60W 50/14 Means for informing the driver, warning the driver or prompting a driver intervention
• CPC Class Codes: G01S 17/58 Velocity or trajectory determination systems; Sense-of-movement determination systems
• CPC Class Codes: G01S 17/931 of land vehicles

Abstract

A vehicle warning system to provide a time-based measure, termed the time-to-last-second-braking time, which is a time buffer that is left for the driver, or control system, to react in order to achieve a desired minimum distance buffer during a collision avoidance process. This measure is based upon a velocity of the host vehicle, an acceleration of the host vehicle, a distance to a lead vehicle, a time rate of change of the distance to the lead vehicle, a relative acceleration between the host and lead vehicles, an acceleration of the host vehicle under maximum braking, and the minimum distance buffer. Various levels of warning may be provided, based upon the value of the time-to-last-second-braking time. Other embodiments are described and claimed.

Claims

1. A system comprising:

a processor system to provide a time-to-last-second-braking measure; and

a warning system coupled to the processor system to provide a first level warning if the time-to-last-second-braking measure is within a first interval.

2. The system as set forth in claim 1, wherein the first level warning is a visual warning.

3. The system as set forth in claim 1, the warning system to further provide a second level warning if the time-to-last-second-braking measure is within a second interval.

4. The system as set forth in claim 3, wherein the first level warning is a visual warning and the second level warning comprises an auditory warning.

5. The system as set forth in claim 1, further comprising:

an override system to provide automatic braking if the time-to-last-second-braking measure is within a third interval.

6. The system as set forth in claim 5, wherein the third interval is the set of real numbers less than a threshold.

7. The system as set forth in claim 1, the processor system to calculate the time-to-last-second-braking measure based upon a velocity of a host vehicle, an acceleration of the host vehicle, a distance to a lead vehicle, a time rate of change of the distance to the lead vehicle, a relative acceleration between the host and lead vehicles, an acceleration of the host vehicle under maximum braking, and a minimum distance buffer.

8. The system as set forth in claim 7, wherein the processor system calculates the time-to-last-second-braking, denoted as T_LSB, to satisfy the relationship

$R=\{\begin{array}{c}{v}_H\end{array}$

T LSB + a H 2 

T LSB 2 - ( v H + a H 

T LSB ) 2 2 

a H 



max + v L 2 2 

a L + R min t LS ≤

t HS - R . 

T LSB - 1 2 

a R 

T LSB 2 + ( R . + a R 

T LSB ) 2 2 

( a L - a H 



max ) + R min t LS >

t HS

where ν

_H denotes the velocity of the host vehicle, α

_H denotes the acceleration of the host vehicle, R denotes the distance to the lead vehicle, {dot over (R)} denotes the time rate of change of the distance to the lead vehicle, α

_R denotes the relative acceleration between the host and lead vehicles, α

_Hmax denotes the acceleration of the host vehicle under maximum braking, and R_min denotes the minimum distance buffer; and

where

$t_{\mathrm{LS}}=\frac{-\left(v_H+\stackrel{.}{R}\right)}{a_R+a_H},<br><br>\mathrm{and}$ $t_{\mathrm{HS}}=T_{\mathrm{LSB}}-\frac{v_H+a_H<br><br>T_{\mathrm{LSB}}}{a_{H<br><br><br><br>\max }}.$

9. A method comprising:

estimating a velocity of a host vehicle, ν

_H;

an acceleration of the host vehicle, α

_H;

a distance to a lead vehicle, R;

a time rate of change of the distance to the lead vehicle, {dot over (R)};

a relative acceleration between the host and lead vehicles, α

_R;

an acceleration of the host vehicle under maximum braking, α

_Hmax; and

a minimum distance buffer, R_min; and

estimating a time-to-last-second-braking measure, T_LSB, based upon the estimated variables ν

_H, α

_H, R, {dot over (R)}, α

_R, α

_Hmax, and R_min.

10. The method as set forth in claim 9, wherein T_LSB satisfies the relationship

$R=\{\begin{array}{c}{v}_H\end{array}$

T LSB + a H 2 

T LSB 2 - ( v H + a H 

T LSB ) 2 2 

a H 



max + v L 2 2 

a L + R min t LS ≤

t HS - R . 

T LSB - 1 2 

a R 

T LSB 2 + ( R . + a R 

T LSB ) 2 2 

( a L - a H 



max ) + R min t LS >

t HS 



where 



t LS = - ( v H + R . ) a R + a H , 

and 



t HS = T LSB - v H + a H 

T LSB a H 



max .

11. The method as set forth in claim 9, further comprising:

providing a first level of warning if T_LSB is within a first interval.

12. The method as set forth in claim 11, wherein the first level of warning is a visual signal.

13. The method as set forth in claim 11, further comprising:

providing a second level of warning if T_LSB is within a second interval.

14. The method as set forth in claim 13, wherein the first level of warning is a visual signal, and the second level of warning comprises a visual warning and an audio warning.

15. An article of manufacture comprising media to store instructions, the instructions to cause a processor system to calculate a time-to-last-second-braking, denoted as T_LSB, such that T_LSB satisfies the relationship

$R=\{\begin{array}{c}{v}_H\end{array}$

T LSB + a H 2 

T LSB 2 - ( v H + a H 

T LSB ) 2 2 

a H 



max + v L 2 2 

a L + R min t LS ≤

t HS - R . 

T LSB - 1 2 

a R 

T LSB 2 + ( R . + a R 

T LSB ) 2 2 

( a L - a H 



max ) + R min t LS >

t HS

where ν

_H denotes a first velocity, α

_H denotes an acceleration, R denotes a distance, {dot over (R)} denotes the time rate of change of the distance, α

_R denotes a relative acceleration, α

_Hmax denotes an acceleration under maximum braking, and R_min denotes a minimum distance buffer; and

where

$t_{\mathrm{LS}}=\frac{-\left(v_H+\stackrel{.}{R}\right)}{a_R+a_H},<br><br>\mathrm{and}$ $t_{\mathrm{HS}}=T_{\mathrm{LSB}}-\frac{v_H+a_H<br><br>T_{\mathrm{LSB}}}{a_{H<br><br><br><br>\max }}.$