Automatic brake control system

• US 5,574,644 A
• Filed: 03/01/1995
• Issued: 11/12/1996
• Est. Priority Date: 03/30/1992
• Status: Expired due to Fees

• Current Assignee: Mazda Motor Corporation
• Original Assignee: Mazda Motor Corporation
• Inventors: Yoshioka, Tohru, Butsuen, Tetsuro
• Primary Examiner(s): Chin, Gary
• Application Number:
  US08/396,943
• Time in Patent Office: 622 Days
• Field of Search: 364/426.04, 364/431.07, 364/460, 364/461, 180/167-170, 180/176-179, 123/350, 123/352, 342/454, 342/455, 340/903, 340/904
• US Class Current: 701/93
• CPC Class Codes: B60K 31/0008 including means for detecting potential obstacles in vehicle path
• CPC Class Codes: B60Q 9/008 for anti-collision purposes
• CPC Class Codes: B60T 7/22 initiated by contact of vehicle, e.g. bumper, with an external object, e.g. another vehicle , or by means of contactless obstacle detectors mounted on the vehicle
• CPC Class Codes: B60T 8/4809 Traction control, stability control, using both the wheel brakes and other automatic braking systems
• CPC Class Codes: B60W 2050/143 Alarm means
• CPC Class Codes: G01S 13/933 of aircraft or spacecraft

Abstract

An automatic brake control system produces a warning before automatically making the braking action of a driving vehicle according to the velocities of the driving vehicle and the vehicle ahead. The system calculates the desired vehicle distance according to the velocities of the driving vehicle and the vehicle ahead, and sets a warning distance which is longer than the desired vehicle distance. The warning distance is set in accordance with the driver'"'"'s feeling. According to the present invention, the system is prevented from producing undesirable warning.

Claims

1. An automatic brake control system for automatically braking a driving vehicle according to velocities of a driving vehicle and a vehicle ahead of said driving vehicle and a vehicle distance therebetween comprising:

first detecting means for detecting respective velocities of the vehicles and the vehicle distance therebetween;

calculating means for calculating a desirable distance to be kept between the vehicles based on the respective velocities of the vehicles detected by the first detecting means;

warning means for producing a warning when an actual distance is smaller than a warning distance which, in turn, is larger than the desirable distance by a predetermined value; and

setting means for automatically controlling the warning distance so that it increases as a velocity difference between the respective velocities of the vehicles is increased.

2. The automatic brake control system according to claim 1, and further comprising:

second detecting means for detecting a friction coefficient of a road surface, and

third detecting means for detecting a deceleration of the driving vehicle and the vehicle ahead of said driving vehicle,

wherein said desirable distance is compensated based upon said friction coefficient and said deceleration is used to determine said warning distance.

3. The automatic brake control system according to claim 2, wherein the desirable distance and the warning distance are provided by the following equations:

space="preserve" listing-type="equation">L.sub.1 =(V.sub.1).sup.2 /2α

.sub.1 g-(V.sub.2).sup.2 /2α

.sub.2 g; and

space="preserve" listing-type="equation">L.sub.2 =(V.sub.1).sup.2 /2α

.sub.1 g-(V.sub.2).sup.2 /2α

.sub.2 g+K(V.sub.1 -V.sub.2).sup.2 ;

wherein L₁ is the desirable distance, L₂ is the warning distance, V₁ and V₂ are the velocities of the driving vehicle and the vehicle ahead of said driving vehicle, respectively, g is the acceleration of gravity, α

₁ g and α

₂ g are the decelerations of the driving vehicle and the vehicle ahead of said driving vehicle, respectively, and K is a safety factor.

4. The automatic brake control system according to claim 3, wherein the safety factor is reduced as a difference between the velocities of the driving vehicle and the vehicle ahead of said driving vehicle, detected by the first detecting means, is increased.