Patent ID: 7983828

Claim:
An automatic brake control device comprising: control means for automatically performing brake control control based on a sensor output including a distance between a subject vehicle and an object existing ahead of the subject vehicle even if there is no driving operation, wherein the control means automatically performs stepwise brake control when an estimated value of time becomes less than a predetermined value; said estimated value being an estimate of time until a distance between the object and the subject vehicle becomes a predetermined distance or less and being based on a relative distance and a relative speed of the object and the subject vehicle obtained by the sensor output, wherein the control means increases a brake force or a brake reduction speed over three stages in time series for performing said stepwise brake control, said control means applying a brake control of a first braking stage until a time limit for avoiding collision by braking operation when the estimated value of time becomes smaller than a predetermined time before the time limit for avoiding collision by braking operation, applying a brake control of a second braking stage until a time limit for avoiding collision by steering operation when the estimated value of time becomes smaller than the time limit for avoiding collision by the braking operation, and applying a brake control of a third braking stage when the estimated value of time becomes smaller than the time limit for avoiding collision by the steering operation, friction coefficient estimating means for estimating a friction coefficient state between a road surface and a tire, and brake reduction speed adjusting means for reducing the braking force or the brake reduction speed of the third braking stage into that of the second braking stage or increases the set value of the time limit for avoiding collision by braking operation and the time limit for avoiding collision by steering operation if an estimation result of the friction coefficient estimating means indicates that the friction coefficient is small but does not generate slip.