Collision preventing system for vehicle

• US 5,286,099 A
• Filed: 06/05/1992
• Issued: 02/15/1994
• Est. Priority Date: 06/07/1991
• Status: Expired due to Fees

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Sato, Makoto, Arai, Toshiaki, Fujita, Yasuhiko
• Primary Examiner(s): Oberleitner, Robert J.
• Assistant Examiner(s): Muratori, Alfred
• Application Number:
  US07/892,827
• Time in Patent Office: 620 Days
• Field of Search: 180/271, 180/275, 303/95, 303/96, 303/103, 303/111, 303/100, 364/426.02
• US Class Current: 303/125
• CPC Class Codes: B60T 13/662 characterised by specified functions of the control system components
• CPC Class Codes: B60T 13/745 acting on a hydraulic system, e.g. a master cylinder
• 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 8/267 for hybrid systems with different kind of brakes on different axles
• CPC Class Codes: B60T 8/4072 Systems in which a driver input signal is used as a control signal for the additional fluid circuit which is normally used for braking
• CPC Class Codes: B60T 8/4081 Systems with stroke simulating devices for driver input B60T8/4077 takes precedence
• CPC Class Codes: B60W 2552/40 Coefficient of friction

Abstract

A collision preventing system for vehicles comprising a road surface friction coefficient judgement circuit for judging a friction coefficient of a travel road surface on the basis of a detection value detected by a wheel speed detector, and for outputting a judgement signal, when determination is made that the friction coefficient is equal to or less than a predetermined value, a first comparator adapted to deliver a first brake control signal indicative of a command to continuously operate each brake when there is a high possibility of collision, a second comparator adapted to deliver a second brake control signal indicative of a command to perform a pumping braking when there is a lower possibility of collision than that of the first brake control signal, and a changing-signal outputting circuit for outputting a changing-signal indicative of a command to change the operation control mode for each brake in response to the delivery of the judgement signal from the road surface friction coefficient judgement circuit when the second brake control signal is delivered form the second comparator. With this arrangement, it is possible to conduct the pumping braking at a stage prior to the full braking, and to obtain an appropriate braking force in accordance with the friction coefficient which is determined during the pumping braking. This avoids conveyance of a vague braking feeling to a driver.

Claims

1. A collision preventing system for a vehicle, including a parameter detector for detecting an operational parameter between a vehicle and a contrast obstruction for judging a possibility of collision of the vehicle against the contrast obstruction, one or more brakes being operated on the basis of a detection value detected by the parameter detector, said system comprising:

a road surface friction coefficient judgement circuit for judging a friction coefficient of a travel road surface on the basis of a detection value detected by a wheel speed detector which detects a speed of each of a plurality of wheels, and for outputting a judgement signal, when determination is made that the friction coefficient is equal to or less than a predetermined value;

a first comparator for comparing the detection value of said parameter detector with a first reference value indicative of a possibility of collision of the vehicle against the contrast obstruction being high, and for outputting, on the basis of the result of such comparison, a first brake control signal indicative of a command to continuously operate each said brake;

a second comparator for comparing the detection value of said parameter detector with a second reference value indicative of a possibility of said collision lower than that in the case of the first reference value, and for outputting, on the basis of the result of such second comparison, a second brake control signal indicative of a command to perform a pumping operation for each said brake; and

a changing-signal output circuit for outputting a changing-signal indicative of a command to change an operation control mode for each brake in response to the judgement signal outputted from said road surface friction coefficient judgement circuit in a condition in which the second brake control signal is outputted from the second comparator.

2. A collision preventing system for vehicles according to claim 1, wherein said road surface friction coefficient judging circuit is arranged to determine that the friction coefficient of the travel road surface becomes equal to or less than the predetermined value, when at least one of the plurality of wheel speeds becomes equal to or less than a reference wheel speed provided by taking account of a predetermined slip rate into a vehicle speed which is estimated on the basis of the plurality of wheel speeds.

3. A collision preventing system for vehicles according to claim 1, wherein the changing-signal outputted from said changing-signal output circuit is a signal indicative of a command to continuously operate each said brake.