JP2015134583A - Driving support device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving support device that can improve collision avoidance performance and collision damage relieving performance when actuating an automatic brake, with a simple structure.SOLUTION: A control portion 3 derives an idle running distance that its own vehicle 1 runs at present vehicle speed in a delay time, calculates corrected deceleration that can eliminate the idle running distance and starts automatic braking at deceleration determined by adding the corrected deceleration to predetermined deceleration. This allows displacement by the idle running distance of a stop position to be improved as in the past, and allows the vehicle 1 to stop before an obstacle B with high reproducibility when actuating the automatic brake, with a simple structure enabling deceleration when starting the automatic brake to be changed.

Description

  The present invention relates to a driving support device that supports collision avoidance and damage reduction with an obstacle ahead of a host vehicle by automatic braking at a predetermined deceleration.

  Conventionally, there has been proposed a driving support device that avoids a collision with an obstacle existing in the traveling direction of the own vehicle by the operation of an automatic brake, and more specifically, the distance from the front obstacle, In order to calculate the collision arrival time TTC, which is an allowance time until the vehicle collides with the front obstacle when traveling at the same speed from the relative speed with the front obstacle, and to avoid collision with the front obstacle The collision avoidance time TTB required for the vehicle, that is, the time required for the host vehicle to make the relative speed with the front obstacle zero by braking operation at a position where the host vehicle and the front obstacle are separated by a predetermined distance. Then, when the collision arrival time TTC becomes the collision avoidance time TTB, a braking operation for avoiding the collision is considered (for example, Patent Document 1).

JP 2008-132867 A (see paragraph 0020 and others)

  However, in the actual vehicle, in addition to the time delay from the start timing of the automatic brake until the brake force of the automatic brake is applied to the host vehicle, the deceleration of the host vehicle is set from the start of the application of the brake force of the automatic brake. Since a delay time due to various causes such as a time delay until reaching the target deceleration and a time delay of the signal transmission system occurs, the collision arrival time TTC is equal to the collision avoidance time TTB as described in Patent Document 1 described above. Even if automatic braking is started, the delay time until the effective automatic braking starts, the vehicle will continue to run at the current vehicle speed and should be stopped by automatic braking. Cannot be stopped, for example, even if the automatic brake is operated to stop before a predetermined distance of the obstacle, Sealed, in the worst case there is a possibility that inconvenience such collision can not be avoided with the obstacle occurs.

  An object of the present invention is to improve the performance of collision avoidance and collision damage reduction when an automatic brake is operated with a simple configuration.

  In order to achieve the above object, the driving support device of the present invention is a driving support device that supports collision avoidance and damage reduction with an obstacle ahead of the host vehicle by automatic braking at a predetermined deceleration set in advance. A distance detecting means for detecting a distance between the host vehicle and the obstacle, a relative speed detecting means for detecting a relative speed between the host vehicle and the obstacle, and a distance and a relative speed between the host vehicle and the obstacle. A collision prediction time calculation means for calculating a collision prediction time until the host vehicle collides with the obstacle based on the automatic braking start condition when the collision prediction time is less than or equal to a preset reference time From the determination that the automatic brake start condition is satisfied by the determination means until the predetermined deceleration is reached after the braking force of the automatic brake is actually applied to the host vehicle. Deriving means for deriving a free running distance in which the host vehicle travels at the current vehicle speed at a time corresponding to the set delay time, and a corrected deceleration that cancels the free running distance by the deriving means And a brake control means for operating the automatic brake at a deceleration obtained by adding the correction deceleration to the predetermined deceleration when the automatic brake start condition is satisfied by the determination unit. (Claim 1).

  According to the first aspect of the invention, it corresponds to a delay time from when the determination means determines that the automatic brake start condition is satisfied until the braking force of the automatic brake is actually applied to the host vehicle and reaches a predetermined deceleration. The idle travel distance at which the vehicle travels at the current vehicle speed in time is derived by the deriving means, and a correction deceleration that cancels the derived idle travel distance is calculated by the correcting means, and when the automatic brake start condition is satisfied, The automatic braking at a deceleration in which the corrected deceleration is added to the predetermined deceleration is operated by the control means.

  At this time, the start timing at which the automatic brake actually starts is the time when the above-described delay time has elapsed since the automatic brake start condition is satisfied, but there is no delay time from the beginning of the automatic brake operation. In this case, automatic braking is started at a deceleration obtained by adding a corrected deceleration to the predetermined deceleration.

  Therefore, in order to start automatic braking by adding the corrected deceleration that cancels the free running distance that the vehicle travels at the current vehicle speed during the delay time to the predetermined deceleration, the stop for the free running distance is performed as before. A simple configuration that can improve the displacement of the position and change the deceleration at the start of automatic braking can stop the vehicle in front of the obstacle with high reproducibility when the automatic brake is activated, avoiding collisions It is possible to improve driving support performance and reduce collision damage.

It is a block block diagram of one Embodiment of the driving assistance device which concerns on this invention. It is operation | movement explanatory drawing of FIG.

  An embodiment of the present invention will be described in detail with reference to the block diagram of FIG. 1 and the operation explanatory diagram of FIG.

  As shown in FIG. 1, a front monitoring sensor 2 composed of a radar such as a laser radar or a millimeter wave radar is provided at the front of the own vehicle 1, and the front monitoring sensor 2 is transmitted from the own vehicle 1 to a preceding vehicle by transmitting and receiving pulse waves. The distance to the front obstacle B is detected, and an output signal corresponding to transmission / reception of a pulse wave from the front monitoring sensor 2 is sent to the control unit 3 having a microcomputer configuration.

  When the front monitoring sensor 2 is a radar, a plurality of pulse waves are transmitted from the front monitoring sensor 2 toward the front of the host vehicle 1 in the vehicle width direction, and reflected from the obstacle B by the front monitoring sensor 2. The obstacle B is detected by receiving the wave. Further, based on the output signal from the forward monitoring sensor 2, the distance D between the host vehicle 1 and the obstacle B is calculated from the time from the transmission of the pulse wave to the reception of the reflected wave by the control unit 3, and the calculated distance From the time change, the control unit 3 detects the relative speed Vr between the host vehicle 1 and the obstacle B.

  Thus, the function for calculating the distance D between the host vehicle 1 and the obstacle B by the front monitoring sensor 2 and the control unit 3 corresponds to the distance detecting means in the present invention, and the host vehicle by the front monitoring sensor 2 and the control unit 3. The function of calculating the relative speed Vr between 1 and the obstacle B corresponds to the relative speed detecting means in the present invention.

  Further, the controller 3 calculates the predicted collision time TTCe until the own vehicle 1 collides with the obstacle B by dividing the calculated distance D between the own vehicle 1 and the obstacle B by the relative speed Vr. . The function of calculating the predicted collision time TTCe by the control unit 3 corresponds to the predicted collision time calculation means in the present invention.

  In addition, the control unit 3 is provided with a memory (not shown) that stores a reference time TTCs that is a criterion for determining whether or not the automatic brake start condition is satisfied, and the calculated collision predicted time TTCe is shorter than the reference time TTCs. At this time, the brake actuator 4 is controlled by the control unit 3, and automatic braking at a deceleration commanded by the control unit 3 is operated by the brake actuator 4. Such a function of determining whether or not the automatic brake start condition is satisfied by the control unit 3 corresponds to the determination means in the present invention.

Here, as will be described later, even if the corrected deceleration α (m / s ² ) is added (added), the maximum deceleration (for example, 1G) that can be generated by the own vehicle 1 is not exceeded. A value slightly smaller than the maximum deceleration that can be generated is preset as the predetermined deceleration A (m / s ² ), and the reference time TTCs stops without colliding with the obstacle B when decelerated at the predetermined deceleration. It is set to a time (a constant value) required until it is stored and stored in the memory.

  By the way, in the own vehicle 1, in addition to the time delay from when the automatic brake start condition is satisfied until the braking force of the automatic brake is actually applied to the own vehicle 1, the own vehicle 1 starts from the start of the application of the braking force of the automatic brake. Since there is a specific delay time ΔT due to various causes such as a time delay until the deceleration of the vehicle reaches a predetermined deceleration set, or a time delay of the signal transmission system, a specific delay time ΔT ( s) is experimentally derived in advance and is stored and held in the above-described memory of the control unit 3, and the host vehicle 1 is detected by the vehicle speed sensor 5 during the delay time ΔT set by being stored in the memory. The free running distance Dn (= ΔT × V) that travels at the current vehicle speed V is derived by the control unit 3. Such a derivation function of the idling distance Dn corresponds to the derivation means in the present invention. The delay time ΔT described above is preferably obtained in advance for each vehicle, but may be obtained in advance for each vehicle type.

  Further, the control unit 3 calculates a corrected deceleration α for correcting the predetermined deceleration A, which is the deceleration of the automatic brake, so as to cancel the derived idling distance Dn, and when the automatic brake start condition is satisfied In order to operate the automatic brake with the deceleration Ar (= A + α) obtained by adding (adding) the corrected deceleration α to the predetermined deceleration A, the control unit 3 instructs the brake actuator 4 to set the deceleration Ar. The automatic brake operation is started. Such a calculation function of the corrected deceleration α by the control unit 3 corresponds to the correction means in the present invention, and a deceleration obtained by adding (adding) the corrected deceleration α to the predetermined deceleration A by the control unit 3 and the brake actuator 4. The function of operating the automatic brake with Ar (= A + α) corresponds to the brake control means in the present invention.

  In such a configuration, as shown in FIG. 2, when the collision prediction time TTCe calculated by the control unit 3 becomes shorter than the reference time TTCs at time t1 and the automatic brake start condition is satisfied, there is no delay time ΔT. Although the automatic brake operation starts immediately after the condition is satisfied, the time from when the automatic brake start condition is satisfied to when the brake force of the automatic brake is actually applied to the own vehicle 1 is actually applied to the own vehicle 1. In addition to the delay, the inherent delay time due to various causes such as the time delay from the start of applying the braking force of the automatic brake until the deceleration of the host vehicle 1 reaches the predetermined deceleration set, the time delay of the signal transmission system, etc. Since ΔT exists, the braking force of the automatic brake is actually applied to the host vehicle 1 at time t2 when the delay time ΔT has elapsed from time t1.

  Then, since the own vehicle 1 runs idle without being braked at the current vehicle speed V during the delay time ΔT from time t1 to t2, the vehicle 1 automatically performs at the normal predetermined deceleration A without time delay at time t1. The host vehicle 1 stops at a time t4 later than the time t3 when the brake is activated and the host vehicle 1 stops, and the host vehicle 1 stops for the idle running distance Dn (= ΔT × V) during the delay time ΔT. The position approaches the obstacle B and stops.

  Therefore, the control unit 3 derives the idle travel distance Dn in which the host vehicle 1 travels at the current vehicle speed V at a time corresponding to the delay time ΔT, and at the current speed V represented by the hatched area in FIG. The corrected deceleration α that cancels the idle running distance Dn is calculated, and the automatic braking at the deceleration Ar (= A + α) obtained by adding (adding) the corrected deceleration α to the predetermined deceleration A is operated. The brake actuator 4 is controlled at the time t1 when the automatic brake start condition is satisfied, and at time t2 when the delay time ΔT has elapsed from the time t1, the braking force by the automatic braking at the deceleration Ar actually starts to operate at the time t3. The host vehicle stops.

  Therefore, according to the above-described embodiment, the deceleration obtained by adding (adding) the corrected deceleration α to the predetermined deceleration A so as to cancel the idle travel distance Dn that the host vehicle 1 travels at the current vehicle speed V during the delay time ΔT. Since the automatic braking is started at the speed Ar, it is possible to improve the deviation of the stop position corresponding to the idling distance Dn as in the past, and the simple configuration of varying the deceleration at the start of the automatic braking makes it possible to The host vehicle 1 can be stopped with good reproducibility before the obstacle B during operation.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the above-described embodiment, the example in which the own vehicle is stopped before the obstacle ahead of the own vehicle by the automatic brake and the collision is avoided is described. Even if collision with an obstacle cannot be avoided, the present invention can also be applied to support for reducing damage at the time of collision as much as possible. In this case as well, there is a delay time ΔT as in the above embodiment. However, it is possible to realize damage reduction by automatic braking similar to the case without delay time.

DESCRIPTION OF SYMBOLS 1 ... Own vehicle 2 ... Forward monitoring sensor (distance detection means, relative speed detection means)
3. Control unit (distance detection means, relative speed detection means, collision prediction time calculation means, determination means, correction means, brake control means)
4. Brake actuator (brake control means)
B ... Obstacle

Claims (1)

In a driving assistance device that supports collision avoidance with an obstacle ahead of the host vehicle and damage reduction by automatic braking at a predetermined deceleration set in advance,
Distance detecting means for detecting the distance between the host vehicle and the obstacle;
A relative speed detecting means for detecting a relative speed between the host vehicle and the obstacle;
A collision prediction time calculation means for calculating a collision prediction time until the host vehicle collides with the obstacle based on a distance and a relative speed between the host vehicle and the obstacle;
Determining means for determining that the automatic brake start condition is satisfied when the predicted collision time is equal to or less than a preset reference time;
A delay time from when the determination means determines that the automatic brake start condition is satisfied to when the braking force of the automatic brake is actually applied to the host vehicle until the predetermined deceleration is reached is set in advance, and the set delay time Deriving means for deriving the free running distance at which the host vehicle is traveling at the current vehicle speed at a time corresponding to
Correction means for calculating a correction deceleration so as to cancel the free running distance by the derivation means;
And a brake control means for operating the automatic brake at a deceleration obtained by adding the corrected deceleration to the predetermined deceleration when the automatic brake start condition is established by the determination means.

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