Apparatus and method of warning rear-end collision

• US 5,502,432 A
• Filed: 12/10/1992
• Issued: 03/26/1996
• Est. Priority Date: 12/16/1991
• Status: Expired due to Fees

• Current Assignee: Stanley Electric Company Limited
• Original Assignee: Stanley Electric Company Limited
• Inventors: Iwasaki, Kazuhisa, Tanabe, Toru, Seto, Takao, Senoo, Yasushi, Ohmamyuda, Yukio, Kimura, Shigeru, Kitamura, Hideki
• Primary Examiner(s): Peng, John K.
• Assistant Examiner(s): Lefkowitz, Edward
• Application Number:
  US07/988,675
• Time in Patent Office: 1,202 Days
• Field of Search: 340/435, 340/436, 340/901, 340/903, 180/271
• US Class Current: 340/436
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/932 using own vehicle data, e.g. ground speed, steering wheel direction
• CPC Class Codes: G01S 2013/9325 for inter-vehicle distance regulation, e.g. navigating in platoons
• CPC Class Codes: G01S 2013/93271 in the front of the vehicles

Abstract

A warning apparatus for warning of possible rear-end collision of a given vehicle having the warning apparatus with another vehicle preceding the given vehicle includes: a computer; a distance sensor for measuring a vehicle-to-vehicle distance to the another preceding vehicle; and a velocity sensor for measuring the velocity of the given vehicle. The computer computes a relative velocity of the given and the another preceding vehicle from a differential of the vehicle-to-vehicle distance and then computes an anticipated rear-end collision time by dividing of the vehicle-to-vehicle distance by the relative velocity of the given vehicle. The computer corrects the anticipated rear-end collision time in response to an acceleration and the relative velocity. The computer produces a warning of signal and an alarm is provided in response to the corrected anticipated rear-end collision time. A method of warning of a possible rear-end collision comprises the step of: detecting a vehicle-to-vehicle distance between a given vehicle and the another vehicle preceding the given vehicle; detecting a velocity of the given vehicle; computing an anticipated rear-end collision time T_a of the given vehicle with the another vehicle, with an equation: ##EQU1## and producing a warning in response to the computed anticipated rear-end collision time T_a.

Claims

1. A warning apparatus for warning of a possible rear-end collision of a given vehicle having the warning apparatus with another vehicle preceding the given vehicle, comprising:

a computer;

a distance means for determining a vehicle-to-vehicle distance between the given vehicle and the another vehicle and for sending a distance signal to said computer;

a velocity means for determining a velocity of the given vehicle and for sending a velocity signal to said computer;

alarm means for receiving a warning signal provided by said computer;

said computer computing an anticipated rear-end collision time T_a of the given vehicle with the another vehicle with an equation;

##EQU10## where T_a is an anticipated rear-end collision time as measured in seconds, X is a vehicle-to-vehicle distance between the given vehicle and the another vehicle measured in meters, T_k is a buffer time measured in seconds, V_m is a velocity of the given vehicle measured in m/s (meters per second), V_r is a relative velocity measured in m/s (meters per second), and G is an acceleration on relative velocity V_r ;

said computer sending said warning signal to said alarm means; and

said alarm means providing a warning in response to the computed anticipated rear-end collision time T_a.

2. A warning apparatus for warning of a possible rear-end collision of a given vehicle, having the warning apparatus with another vehicle, preceding the given vehicle comprising:

a computer;

a distance means for determining a vehicle-to-vehicle distance between the given vehicle and the another vehicle and for sending a distance signal to said computer;

a velocity means for determining a velocity of the given vehicle and for sending a velocity signal to said computer;

a braking means for determining a state of a brake of the given vehicle and for sending a braking signal to said computer;

an acceleration means for determining a degree of opening of an accelerator of the given vehicle and for sending an acceleration signal to said computer;

alarm means for receiving a warning signal from said computer;

said computer computing an anticipated rear-end collision time T_a of the given vehicle with the another vehicle with an equation;

##EQU11## where T_a is an anticipated rear-end collision time measured in seconds, X is a vehicle-to-vehicle distance between the given vehicle and the another vehicle measured in meters, T_k is a buffer time measured in seconds, V_m is a velocity of the given vehicle measured in m/s (meters per second), α

is a present state parameter of the given vehicle, V_r is a relative velocity measured in m/s (meters per second), and G is an acceleration on relative velocity V_r ;

said computer sending said warning signal to said alarm means, said computer changing a value of the parameter α

in response to a braking signal of the given vehicle and an acceleration signal of the given vehicle; and

said alarm means providing a warning in response to the computed anticipated rear-end collision time T_a.

3. A method for warning of a possible rear-end collision between two vehicles, comprising the steps of:

determining a vehicle-to-vehicle distance between a given vehicle and another vehicle preceding said given vehicle;

determining a velocity of said given vehicle;

computing an anticipated rear-end collision time T_a of said given vehicle with said another vehicle with an equation;

##EQU12## where T_a is an anticipated rear-end collision time measured in seconds, X is vehicle-to-vehicle distance between the given vehicle and said another vehicle measured in meters, T_k is a buffer time measured in seconds, V_m is a velocity of the given vehicle measured in m/s (meters per second), V_r is relative velocity measured in m/s (meters per second) and, G is an acceleration on relative velocity V_r ; and

producing a warning in response to said computed anticipated rear-end collision time T_a.

4. A method for warning of a possible rear-end collision between two vehicles, comprising the steps of:

determining a vehicle-to-vehicle distance between a given vehicle and another vehicle preceding said given vehicle;

determining a velocity of said given vehicle;

determining a state of a brake of said given vehicle;

determining a degree of opening of an accelerator of said given vehicle;

computing an anticipated rear-end collision time T_a between said given and said another vehicle with an equation;

##EQU13## where T_a is an anticipated rear-end collision time as measured in seconds, X is a vehicle-to-vehicle distance between said given vehicle and said another vehicle measured in meters, T_k is a buffer time measured in seconds, V_m is a velocity of the given vehicle in m/s (meters per second), α

is a present state parameter of the given vehicle, V_r is a relative velocity in m/s (meters per second) and, G is an acceleration on relative velocity V_r, the value of said parameter α

depending on a present state of the brake of said given vehicle and a degree of opening of an accelerator of said given vehicle; and

providing a warning in response to the computed anticipated rear-end collision time T_a.

5. A method for warning of a potentially impending rear-end collision between a given vehicle and another vehicle preceding and spaced apart from said given vehicle, comprising the steps of:

determining a vehicle-to-vehicle distance between said given and said another vehicle;

determining a present velocity of said given vehicle;

calculating a relative velocity of said given vehicle relative to said another vehicle;

computing an anticipated rear-end collision time between said given vehicle and said another vehicle, if said calculated relative velocity of said given vehicle to said another vehicle will decrease said distance therebetween; and

providing a warning in response to said computed anticipated rear-end collision time.

6. The method of claim 5, wherein said determining a vehicle-to-vehicle distance step comprises monitoring said vehicle-to-vehicle distance as said distance between said given vehicle and said another vehicle decreases.

7. The method of claim 5, further comprising:

ascertaining a decrease in said distance between said given vehicle and said another vehicle;

said ascertaining step including adjusting a determination that said distance is decreasing, based upon;

a present state of a braking means of said given vehicle; and

a present state of an accelerator of said given vehicle.

8. A warning apparatus for warning of a potentially impending rear-end collision between a given vehicle and another vehicle preceding and spaced apart from said given vehicle comprising:

means for determining a vehicle-to-vehicle distance between said given and said another vehicle;

means for determining a present velocity of said given vehicle;

calculating means for calculating a relative velocity of said given vehicle relative to said another vehicle;

computing means for computing an anticipated rear-end collision time between said given vehicle and said another vehicle, if said calculated relative velocity of said given vehicle and said another vehicle is decreasing said distance therebetween; and

warning means for providing a warning in response to the computed anticipated rear-end collision time.

9. The warning apparatus of claim 8, wherein the means for determining a vehicle-to-vehicle distance comprises means for monitoring said vehicle-to-vehicle distance between said given vehicle and said another vehicle.

10. The warning apparatus of claim 8, further comprising:

ascertaining means for ascertaining a decrease in said distance between said given vehicle and said another vehicle;

said ascertaining means including means for adjusting a determination that said distance is decreasing, based upon a present state of a braking means of said given vehicle and a present state of an accelerator of said given vehicle.