Vehicle driving support apparatus
View Patent ↗A pressure reduction start distance is obtained (S 9 ) based upon a deceleration after an operation of an automatic brake. When an obstacle-to-vehicle distance between a vehicle and an obstacle ahead becomes a distance obtained by adding the pressure reduction start distance to a target stopping distance to the obstacle ahead, the reduction of the brake pressure is started (S 11 ) to suppress a pitching vibration generated before and after the vehicle stops. When the obstacle-to-vehicle distance becomes a stopping brake start distance that is just before the target stopping distance, the brake pressure is increased (S 13 ) so as to allow the vehicle to stop.
1. A vehicle driving support apparatus comprising:
a forward-monitoring unit to monitor a driving environment ahead of a vehicle in an advancing direction of the vehicle, the forward-monitoring unit is mounted to the vehicle;
a time-to-collision calculating unit to detect an obstacle ahead using the driving environment ahead of the vehicle, which is detected by the forward-monitoring unit, and to calculate a time-to-collision when the vehicle collides with the obstacle ahead using an obstacle-to-vehicle distance between the obstacle ahead and the vehicle and a relative vehicle speed; and
an automatic braking control unit to operate an automatic braking to stop the vehicle and to avoid a collision with the obstacle ahead when the time-to-collision is less than a predetermined braking assist determination time,
wherein the automatic braking control unit, when starting to operate the automatic braking, calculates a braking pressure reduction start distance proportional to a deceleration of the vehicle using the deceleration of the vehicle within a predetermined time of the start of the automatic braking, the braking pressure reduction start distance where a control for temporarily reducing a braking pressure by the automatic braking starts to be executed before the vehicle is stopped at a target stopping position by the automatic braking, reduces the braking pressure by the automatic braking when detecting that the obstacle-to-vehicle distance is equal to or less than the pressure reduction start distance, and increases the reduced braking pressure when the obstacle-to-vehicle distance is equal to or less than a predetermined stopping braking start distance immediately before the vehicle stops.
2. The vehicle driving support apparatus according to claim 1 , wherein the automatic braking control unit fully closes a throttle valve when the automatic braking is operated.
3. The vehicle driving support control apparatus according to claim 2 , wherein the automatic braking control unit reduces the braking pressure in a stepwise manner with a predetermined ratio.
4. The vehicle driving support control apparatus according to claim 1 , wherein the automatic braking control unit reduces the braking pressure in a stepwise manner with a predetefinined ratio.
5. The vehicle driving support control apparatus according to claim 1 , further comprising a sensor which outputs the deceleration of the vehicle.
6. The vehicle driving support control apparatus according to claim 1 , wherein the braking pressure reduction start distance is proportional to the deceleration of the vehicle.
7. The vehicle driving support control apparatus according to claim 6 , wherein the braking pressure reduction start distance becomes longer as the deceleration of the vehicle increases.
8. The vehicle driving support control apparatus according to claim 6 , wherein the braking pressure reduction start distance becomes shorter as the deceleration of the vehicle decreases.
9. The vehicle driving support control apparatus according to claim 1 , wherein a deceleration of the vehicle immediately before the vehicle stops is greater than a deceleration of the vehicle immediately before the target stopping position.
10. The vehicle driving support control apparatus according to claim 1 , wherein the automatic braking control unit further:
operates the automatic braking to decelerate the vehicle when the time-to-collision is less than a predetermined braking assist determination time at a first deceleration value;
reduces the braking pressure of the automatic braking to decrease the deceleration of the vehicle immediately before a target stopping position at a second deceleration value that decreases in a stepwise manner; and
increases the reduced braking pressure to increase the deceleration of the vehicle until immediately before the vehicle stops at a third deceleration value,
wherein the first deceleration value is greater than the second deceleration value, and
wherein the third deceleration value is greater than a smallest value of the second deceleration value.
11. A vehicle driving support apparatus comprising:
a forward-monitoring unit that is mounted to a vehicle for monitoring a driving environment ahead of the vehicle in the advancing direction;
a time-to-collision calculating unit that detects an obstacle ahead based upon the driving environment ahead of the vehicle, which is detected by the forward-monitoring unit, and obtains a time-to-collision based upon an obstacle-to-vehicle distance between the obstacle ahead and the vehicle and a relative vehicle speed; and
an automatic braking control unit that:
operates an automatic braking to decelerate the vehicle when the time-to-collision is less than a predetermined braking assist determination time;
reduces a braking pressure of the automatic braking to decrease a deceleration of the vehicle immediately before a target stopping position, set in advance, that the vehicle maintains with respect to the obstacle ahead; and
increases the reduced braking pressure to increase the deceleration of the vehicle until immediately before the vehicle stops.