JP2017105357A - Safety device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a safety device which calculates a permission time or a permission distance for permitting that a driver of a vehicle is in a front non-watching state.SOLUTION: A safety device 10 comprises: an own vehicle speed acquisition part 31 which acquires a speed of an own vehicle; a preceding vehicle speed acquisition part 32 which acquires a speed of a preceding vehicle; an inter-vehicle distance acquisition part 33 which acquires an inter-vehicle distance between the own vehicle and the preceding vehicle; a driver state detection part 20 which detects whether or not a driver of the own vehicle is in a front non-watching state; a collision position prediction part 34 which predicts a collision position in which the own vehicle collides with the preceding vehicle when it is assumed that the own vehicle is not decelerated in speed on the basis of at least the speed of the preceding vehicle; a deceleration region calculation part 35 which calculates a deceleration time or a deceleration distance which is necessary for a time or a distance before the speed of the own vehicle reaches the speed of the preceding vehicle in the collision position; and a permission region calculation part 36 which calculates a permission time or a permission distance for permitting that the driver of the own vehicle is in the front non-watching state on the basis of the inter-vehicle distance, the collision position and the deceleration distance.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a vehicle safety device.

  2. Description of the Related Art Conventionally, there has been known an apparatus that provides assistance to a driver of the host vehicle to avoid the host vehicle from colliding with a preceding vehicle according to the driver's state. For example, Patent Document 1 discloses a safety device that outputs a warning to a driver when a state in which the driver's arousal level of the host vehicle has been reduced continues for a preset time.

JP 2012-252497 A

  When an alarm is output when the state in which the driver's arousal level has decreased lasts for a preset time, the distance between the preceding vehicle and the host vehicle is large, and therefore the risk of the host vehicle colliding with the preceding vehicle is high. Even if it is low, an alarm is output. When the safety device outputs an alarm when the degree of danger is low, the driver may feel that the safety device is bothersome.

  Therefore, the present invention has been made in view of these points, and an object of the present invention is to provide a safety device that calculates an allowable time or an allowable distance that allows a driver of a vehicle to be in a forward gazing state. .

  In an aspect of the present invention, a host vehicle speed acquisition unit that acquires a speed of the host vehicle, a preceding vehicle speed acquisition unit that acquires a speed of a preceding vehicle preceding the host vehicle, and the host vehicle and the preceding vehicle An inter-vehicle distance acquisition unit that acquires an inter-vehicle distance, a driver state detection unit that detects whether or not the driver of the host vehicle is in a forward gazing state in which the driver is not gazing forward, and at least of the preceding vehicle Based on the speed, when it is assumed that the host vehicle does not decelerate, a collision position prediction unit that predicts a collision position where the host vehicle collides with the preceding vehicle, and the speed of the host vehicle is the host vehicle speed acquisition unit. Is based on the deceleration area calculation unit that calculates the deceleration time or the deceleration distance required to decelerate to the speed of the preceding vehicle at the collision position from the acquired speed, the inter-vehicle distance, the collision position, and the deceleration distance And a reasonable area calculation unit that calculates a permissible time or allowed distance allows the said driver of said vehicle is in said forward non gaze condition, to provide a safety device.

  The collision position prediction unit predicts, as the collision position, a stop position of the preceding vehicle when it is assumed that the preceding vehicle starts to decelerate and stop when the driver state detection unit detects the forward gazing state. May be.

  The deceleration area calculation unit includes an idle running distance calculated based on a response time of a driver of the own vehicle, a brake rising distance calculated based on a brake rising time of the own vehicle, The deceleration distance may be calculated based on the braking distance calculated based on the deceleration.

  The safety device is provided in the host vehicle when a duration time during which the driver state detection unit continuously detects the forward gazing state is equal to or longer than the allowable time calculated by the allowable region calculation unit. An alarm control unit that causes the alarm device to output a main alarm may be further provided.

  In the safety device, a continuation time in which the driver state detection unit continuously detects the forward gazing state is equal to or longer than the allowable time calculated by the allowable region calculation unit, and a predetermined minimum continuation time When it is above, you may further provide the alarm control part which outputs the main alarm to the alarm device provided in the own vehicle.

  The alarm control unit is configured to detect the main alarm when a duration time during which the driver state detection unit continuously detects the forward gazing state is less than the allowable time calculated by the allowable region calculation unit. The alarm device may output a preliminary alarm that is suppressed as compared with the above.

  The alarm control unit outputs a main alarm to the alarm device when a duration during which the driver state detection unit continuously detects the forward gazing state is a predetermined maximum allowable duration or more. You may let them.

  According to the present invention, it is possible to calculate a permissible time or permissible distance that allows the driver of the vehicle to be in a forward gazing state.

It is a figure for demonstrating the outline | summary of the safety device which concerns on this embodiment. It is a block diagram which shows the structure of the own vehicle which concerns on this embodiment. It is a flowchart which shows operation | movement of a safety device. It is a figure for demonstrating the procedure in which a safety device calculates an allowable distance. In the modification of this embodiment, it is a figure for demonstrating the procedure in which a safety device calculates an allowable distance.

[Overview of this embodiment]
Even when the safety device according to the present embodiment detects that the driver of the host vehicle is in a forward gazing state in which the driver is not gazing forward, the safety device can avoid a collision with the preceding vehicle. Does not output an alarm or suppresses an alarm output. This can prevent the driver from feeling that the safety device is bothersome.

  FIG. 1 is a diagram for explaining the outline of the safety device according to the present embodiment. FIG. 1A is a diagram illustrating a traveling state of the host vehicle 1 and the preceding vehicle 2 when the safety device detects that the driver of the host vehicle 1 is in a forward gazing state. In the following description, the time when the safety device detects that the driver of the host vehicle 1 is in a forward gazing state is referred to as a starting point. First, the safety device acquires information on the speed Vf of the host vehicle 1 at the starting point, the speed Vp of the preceding vehicle 2 preceding the host vehicle 1, and the inter-vehicle distance Dr between the host vehicle 1 and the preceding vehicle 2. .

  Subsequently, the safety device calculates an allowable distance Da_f of the host vehicle 1. The permissible distance Da_f is a distance that allows the driver of the host vehicle 1 to be in a forward gazing state. When the allowable distance Da_f is 100 m, for example, the safety device requires the driver of the own vehicle 1 to decelerate the own vehicle 1 before the own vehicle 1 travels 100 m after the driver enters the forward gazing state. Can be detected, the collision between the host vehicle 1 and the preceding vehicle 2 can be avoided. In FIG. 1B, after the own vehicle 1 travels from the position of the starting point by the allowable distance Da_f, the driver of the own vehicle 1 senses the necessity of deceleration of the own vehicle 1 and the own vehicle 1 starts decelerating. And the situation where the own vehicle 1 stopped just before the stop position P of the preceding vehicle 2 is shown.

  Hereinafter, an outline of a method for the safety device to calculate the allowable distance Da_f will be described. In the present embodiment, first, the safety device assumes that the preceding vehicle 2 starts to decelerate at the starting point. Subsequently, the safety device calculates a distance Ds_p that the preceding vehicle 2 travels from when the preceding vehicle 2 starts to decelerate until it stops, and calculates a stop position P at which the preceding vehicle 2 stops. . Subsequently, the safety device calculates a deceleration distance Ds_f traveled by the host vehicle 1 after the driver of the host vehicle 1 senses the necessity of deceleration of the host vehicle 1 until the host vehicle 1 stops. Subsequently, the safety device calculates the allowable distance Da_f by subtracting the deceleration distance Ds_f of the host vehicle 1 from the distance between the position of the host vehicle 1 and the stop position P of the preceding vehicle 2 at the starting point.

  According to the present embodiment, the safety device controls the timing of outputting an alarm for allowing the driver to detect the necessity of deceleration of the host vehicle 1 based on the allowable distance Da_f, thereby reducing the risk of collision. When it is low, it is possible to suppress outputting an alarm. For this reason, it can suppress that a driver | operator feels that a safety device is troublesome.

[Configuration of own vehicle]
FIG. 2 is a block diagram showing a configuration of the host vehicle 1 according to the present embodiment. The host vehicle 1 includes a driver monitoring device 3, a vehicle outside monitoring device 4, a safety device 10, and an alarm device 5.

  The driver monitoring device 3 is, for example, a closed eye state detection device that detects whether or not the driver is in the closed eye state. In this case, the driver monitoring device 3 includes, for example, a CCD camera installed on the dashboard of the host vehicle 1. Hereinafter, an example of the operation of the driver monitoring device 3 will be described.

  First, the driver monitoring device 3 captures a region including the driver's eyeball of the traveling vehicle 1 at a predetermined sampling period (for example, 1800 times per minute) to generate an image. Subsequently, the driver monitoring device 3 calculates the degree of eye opening of the driver in the image. The eye opening degree is a ratio of the area of the driver's eyeball in the image to a predetermined reference area. Subsequently, the driver monitoring device 3 determines that the state of the driver is the closed state when the degree of opening of the driver in the image is equal to or less than a predetermined threshold. The driver monitoring device 3 outputs the determination result to the safety device 10.

Depending on the situation, the driver monitoring device 3 may not be able to calculate the area of the driver's eyeball in the image. For example, when the angle of the driver's face is deviated from the front, the detection of the driver's eyeball is hindered by sunlight.
If the driver monitoring device 3 cannot calculate the area of the driver's eyeball in the image, the driver monitoring device 3 may output lost information indicating that the degree of eye opening could not be calculated to the safety device 10. .

  Further, the driver monitoring device 3 can detect the driver's face in the image, but when the area of the eyeball cannot be calculated, the value of the degree of eye opening calculated based on the image taken at the previous sampling period May be used as the value of the degree of eye opening in the current sampling period. By doing in this way, it can control that the output of driver monitoring device 3 fluctuates frequently due to low detection accuracy of a driver's face and eyeball in driver monitoring device 3. . In addition, when such an interpolation process is continued over a long period of time, the possibility of erroneous detection of a closed eye state increases. Therefore, it is preferable to set a predetermined upper limit on the number of sampling periods in which interpolation processing is continuously performed.

  The out-of-vehicle monitoring device 4 is ACC (adaptive cruise control), CMS (collision reduction brake system), or the like. The out-of-vehicle monitoring device 4 acquires information on the relative speed between the host vehicle 1 and the preceding vehicle 2 and the inter-vehicle distance between the host vehicle 1 and the preceding vehicle 2, and sends the acquired information to the safety device 10. Output.

  Based on the information from the driver monitoring device 3, the safety device 10 detects whether or not the driver of the host vehicle 1 is in a forward gazing state where the driver is not gazing forward. Further, when the safety device 10 detects that the driver of the host vehicle 1 is in the forward unfocused state, the driver of the host vehicle 1 is in the forward unfocused state based on the information from the outside monitoring device 4. An allowable distance and an allowable time are calculated. The safety device 10 controls the timing at which the alarm device 5 outputs an alarm based on the calculated allowable time.

  Based on the control from the safety device 10, the alarm device 5 outputs an alarm indicating that the driver is in a forward gazing state. The alarm device 5 includes, for example, a speaker provided in the host vehicle 1.

[Configuration of safety device]
Hereinafter, the configuration of the safety device 10 will be described in detail. The safety device 10 includes a driver state detection unit 20, a vehicle state calculation unit 30, and an alarm control unit 40.

  Based on information from the driver monitoring device 3, the driver state detection unit 20 detects whether or not the driver of the host vehicle 1 is in a forward gazing state. For example, the driver state detection unit 20 detects that the driver of the host vehicle 1 is in a forward gazing state based on information that the driver of the host vehicle 1 is in a closed eye state.

  The vehicle state calculation unit 30 calculates the allowable distance Da_f described above based on information from the outside monitoring device 4. For example, the vehicle state calculation unit 30 calculates the allowable distance Da_f after the driver state detection unit 20 detects that the driver of the host vehicle 1 is in a forward gazing state. The vehicle state calculation unit 30 includes a host vehicle speed acquisition unit 31, a preceding vehicle speed acquisition unit 32, an inter-vehicle distance acquisition unit 33, a collision position prediction unit 34, a deceleration region calculation unit 35, and an allowable region calculation unit 36. Specific operations of each component of the vehicle state calculation unit 30 will be described later.

  The warning control unit 40 controls whether or not the warning device 5 outputs a warning based on information from the driver state detection unit 20 and the vehicle state calculation unit 30.

[Operation of safety device]
Hereinafter, the operation of the safety device 10 will be described. FIG. 3 is a flowchart showing the operation of the safety device. FIG. 4 is a diagram for explaining a procedure by which the safety device 10 calculates the allowable distance Da_f.

  The driver state detection unit 20 of the safety device 10 repeatedly detects at a predetermined cycle whether or not the driver of the host vehicle 1 is in a forward gazing state (S11). When the driver of the host vehicle 1 is in a forward gazing state (YES in S11), the host vehicle speed acquisition unit 31 acquires the speed Vf of the host vehicle 1 based on, for example, the number of rotations of the tire (S12). Moreover, the preceding vehicle speed acquisition part 32 acquires the speed Vp of the preceding vehicle 2 based on the information from the vehicle outside monitoring apparatus 4 (S13). Further, the inter-vehicle distance acquisition unit 33 acquires the inter-vehicle distance Dr between the host vehicle 1 and the preceding vehicle 2 based on information from the outside monitoring device 4 (S14). The own vehicle speed acquisition unit 31, the preceding vehicle speed acquisition unit 32, and the inter-vehicle distance acquisition unit 33 output the acquired information to the collision position prediction unit 34.

  Subsequently, the collision position prediction unit 34 predicts the collision position based on information such as the speed Vf of the host vehicle 1, the speed Vp of the preceding vehicle 2, and the inter-vehicle distance Dr (S15). The collision position means that when the host vehicle 1 is not decelerated after the counting point t0 when the driver state detection unit 20 detects the driver's forward gazing state, the host vehicle 1 is the preceding vehicle 2. It is a position to collide with. In the present embodiment, the collision position prediction unit 34, as shown by a broken line in FIG. 4B, is the stop position P of the preceding vehicle 2 when it is assumed that the preceding vehicle 2 starts to decelerate and stops at the starting point t0. Is predicted as the collision position. The stop position P of the preceding vehicle 2 is a position obtained by adding a distance Ds_p traveled by the preceding vehicle 2 from the start of the deceleration to the stop of the preceding vehicle 2 at the starting point.

Specifically, the collision position prediction unit 34 calculates the distance Ds_p based on the following equation (1).
Ds_p = (Tb_p × Vp) + Vp ² / 2αp (1)
In equation (1), αp is the maximum deceleration of the preceding vehicle 2, and Tb_p is the brake rise time of the preceding vehicle 2. The brake rising time is the time from when the driver starts to brake the vehicle until the vehicle deceleration reaches the maximum deceleration.

In Equation (1), the term Tb_p × Vp represents the brake rising distance Ds_p1 that the preceding vehicle 2 travels during the brake rising time Tb_p. The term Vp ² / 2αp represents the braking distance Ds_p2 required for the preceding vehicle 2 to decelerate from the speed Vp to the speed zero at the maximum deceleration αp.

  The collision position prediction unit 34 may calculate a deceleration time Ts_p that is a time required for the preceding vehicle 2 to stop after starting to decelerate.

  Subsequently, after the driver of the host vehicle 1 detects that the host vehicle 1 needs to be decelerated, the deceleration area calculation unit 35 reduces the speed of the host vehicle 1 from the speed Vf at the starting point t0 to the collision avoidance speed. The deceleration distance Ds_f required until this time is calculated (S16). The collision avoidance speed is, for example, the speed of the preceding vehicle 2 at the collision position. This is because if the speed of the host vehicle 1 can be made lower than the speed of the preceding vehicle 2 at the collision position before the host vehicle 1 reaches the collision position, the collision between the host vehicle 1 and the preceding vehicle 2 can be avoided. Because it can.

When the collision position is the stop position P of the preceding vehicle 2, the deceleration area calculation unit 35 calculates the distance required to reduce the speed of the host vehicle 1 from Vf to zero, as indicated by a broken line in FIG. Calculated as the deceleration distance Ds_f. Specifically, the deceleration area calculation unit 35 calculates the deceleration distance Ds_f based on the following equation (2).
Ds_f = (RTf × Vf) + (Tb_f × Vf) + Vf ² / 2αf (2)
In Formula (2), RTf is a reaction time from when the driver of the host vehicle 1 senses the necessity of deceleration of the host vehicle 1 until the driver starts stepping on the brake. Further, αf is the maximum deceleration αf of the host vehicle 1, and Tb_f is a brake rising time of the host vehicle 1.

In Equation (2), the term RTf × Vf represents the free running distance Ds_f1 that the host vehicle 1 travels during the reaction time RTf. The term Tb_f × Vf represents the brake rising distance Ds_f2 that the host vehicle 1 travels during the brake rising time Tb_f. The term Vf ² / 2αf represents the braking distance Ds_f3 required for the host vehicle 1 to decelerate from the speed Vf to the speed zero at the maximum deceleration αf.
The deceleration area calculation unit 35 may calculate a deceleration time Ts_f that is a time required for the host vehicle 1 to start and stop after decelerating.

Subsequently, the permissible area calculation unit 36 calculates the permissible distance Da_f that allows the driver of the host vehicle 1 to be in the forward non-gaze state based on the following equation (3) (S17).
Da_f = Dr + Ds_p-Ds_f (3)

  Subsequently, the permissible area calculation unit 36 divides the permissible distance Da_f by the speed Vf of the host vehicle 1 at the starting point, thereby allowing the driver of the host vehicle 1 to be in a forward gazing state Ta_f. Is calculated (S18).

  Subsequently, the alarm control unit 40 detects whether or not the driver's forward gazing state of the driver of the host vehicle 1 continues based on the information from the driver state detection unit 20 (S19). When the driver's forward gazing state of the driver of the own vehicle 1 is continued (YES in S19), the alarm control unit 40 is the time during which the driver's forward gazing state of the driver of the own vehicle 1 is continued (hereinafter, continued). (Referred to as time) is calculated (S20). Subsequently, the alarm control unit 40 determines whether or not the duration of the forward gazing state is equal to or longer than the allowable time Ta_f calculated by the allowable region calculation unit 36 (S21). If the duration of the forward gazing state is equal to or longer than the allowable time Ta_f (YES in S21), the alarm control unit 40 causes the alarm device 5 to output a main alarm (S22). As a result, the driver of the host vehicle 1 can be made aware that the driver is in a forward gazing state and that the host vehicle 1 needs to be decelerated.

<Effect in this embodiment>
The safety device 10 according to the present embodiment detects the speed Vf of the own vehicle 1, the speed Vp of the preceding vehicle 2, and the own vehicle 1 and the preceding vehicle 2 when detecting that the driver of the own vehicle 1 is in the forward gazing state. Based on the inter-vehicle distance Dr between the vehicle and the vehicle, a permissible time Ta_f that allows the driver of the host vehicle 1 to be in a forward gazing state is calculated. For this reason, by controlling the alarm device 5 based on the allowable time Ta_f, it is possible to suppress the output of an alarm when the risk of collision between the host vehicle 1 and the preceding vehicle 2 is low. For example, the safety device 10 causes the alarm device 5 to output a main alarm when the duration of the forward gazing state is equal to or longer than the allowable time Ta_f. By doing in this way, it can suppress that a driver | operator feels that the safety device 10 is troublesome.

  Further, the safety device 10 has a stop position of the preceding vehicle 2 when it is assumed that the preceding vehicle 2 starts to decelerate and stops when the driver state detection unit 20 detects the driver's forward non-gaze state of the host vehicle 1. Predicting P as a collision position, the allowable time Ta_f is calculated. That is, the safety device 10 calculates the allowable time Ta_f assuming the worst case. For this reason, the collision with the own vehicle 1 and the preceding vehicle 2 can be avoided more reliably.

  Further, the safety device 10 includes an idle running distance Ds_f1 calculated based on the reaction time RTf of the driver of the own vehicle 1, a brake rising distance Ds_f2 calculated based on the brake rising time Tb_f of the own vehicle 1, Based on the braking distance Ds_f3 calculated based on the maximum deceleration αf of the host vehicle 1, the deceleration distance Ds_f of the host vehicle 1 is calculated. By doing so, the deceleration distance Ds_f of the host vehicle 1 can be calculated more accurately, so that the collision between the host vehicle 1 and the preceding vehicle 2 can be avoided more reliably.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

(Variation of vehicle state calculation unit)
For example, in this embodiment, assuming that the preceding vehicle 2 starts decelerating at the starting point, an example of calculating the collision position of the own vehicle 1 and the preceding vehicle 2, the deceleration time Ts_f of the own vehicle 1 and the allowable distance Da_f is calculated. Although shown, it is not limited to this. In this modification, it is assumed that the own vehicle 1 collides with the preceding vehicle 2 by maintaining the situation where the speed of the own vehicle 1 is higher than the speed of the preceding vehicle 2, and the collision between the own vehicle 1 and the preceding vehicle 2 occurs. An example of calculating the position P, the deceleration time Ts_f of the host vehicle 1 and the allowable distance Da_f will be described.

  FIG. 5 is a diagram for explaining a procedure by which the vehicle state calculation unit 30 of the safety device 10 according to the present modification calculates the allowable distance Da_f. In this modified example, as shown in FIG. 5A, the slope of the graph of the host vehicle 1 is larger than the slope of the graph of the preceding vehicle 2 at the starting point t0. That is, at the starting point t0, the speed Vf of the host vehicle 1 is higher than the speed Vp of the preceding vehicle 2.

  In this modification, the collision position prediction unit 34 of the vehicle state calculation unit 30 assumes that the difference between the speed of the host vehicle 1 and the speed of the preceding vehicle 2 is maintained after the counting point t0 (FIG. 5 ( As shown in b), the collision position P where the host vehicle 1 collides with the preceding vehicle 2 is calculated. Further, the collision position prediction unit 34 calculates a distance Ds_p between the position of the preceding vehicle 2 and the collision position P at the counting point t0.

  Subsequently, as shown in FIG. 5 (c), the deceleration area calculation unit 35 detects the necessity of deceleration of the host vehicle 1 after the driver of the host vehicle 1 determines that the speed of the host vehicle 1 is the starting point t 0. The deceleration distance Ds_f required to decelerate from the speed Vf to the collision avoidance speed is calculated. The collision avoidance speed is the speed of the preceding vehicle 2 at the collision position P, as in the above-described embodiment. In this modification, the speed of the preceding vehicle 2 at the collision position P is equal to the speed Vp of the preceding vehicle 2 at the starting point t0. Accordingly, the deceleration area calculation unit 35 calculates the distance required to decelerate the speed of the host vehicle 1 from the speed Vf of the host vehicle 1 at the starting point t0 to the speed Vp of the preceding vehicle 2 at the starting point t0 as the deceleration distance Ds_f. To do.

  Subsequently, the allowable area calculation unit 36 calculates the allowable distance Da_f based on the inter-vehicle distance Dr, the distance Ds_p, and the deceleration distance Ds_f using the above-described equation (3). Subsequently, the allowable area calculation unit 36 calculates the allowable time Ta_f based on the allowable distance Da_f. Also in the present modification, by controlling the alarm device 5 based on the allowable time Ta_f, it is possible to suppress the output of an alarm when the risk of collision between the host vehicle 1 and the preceding vehicle 2 is low.

(Modification 1 of the alarm control unit)
In the above-described embodiment, the alarm control unit 40 generates an alarm when the duration time during which the driver state detection unit 20 continuously detects the forward unfocused state of the host vehicle 1 is equal to or longer than the allowable time Ta_f. Although the example which outputs the main alarm to the apparatus 5 was shown, it is not restricted to this. The alarm control unit 40 may cause the alarm device 5 to output a main alarm only when the duration of the forward gazing state is equal to or longer than the allowable time Ta_f and equal to or longer than the predetermined minimum duration. That is, the alarm control unit 40 does not cause the alarm device 5 to output the main alarm when the duration of the forward gazing state is less than the minimum duration. The minimum duration is 1 second, for example. By setting such a minimum duration, it is possible to suppress the main alarm from being output due to the driver blinking or the driver visually recognizing the instrument.

(Modification 2 of the alarm control unit)
Further, the alarm control unit 40 warns the alarm device 5 not only when the duration of the forward gazing state is equal to or longer than the allowable time Ta_f but also when the duration of the forward gazing state is less than the allowable time Ta_f. May be output. For example, the alarm control unit 40 suppresses, when the duration of the forward gazing state is less than the allowable time Ta_f, compared to the main alarm output when the duration of the forward gazing state is equal to or longer than the allowable time Ta_f. The prepared preliminary alarm is output to the alarm device 5. When the alarm device 5 includes a speaker, the preliminary alarm is an alarm having a volume lower than that of the main alarm, for example. By doing in this way, the alarm which alarm device 5 outputs can be strengthened in steps.

(Modification 3 of the alarm control unit)
Further, the alarm control unit 40 may cause the alarm device 5 to output a main alarm based on the duration of the forward gazing state without depending on the value of the allowable time Ta_f calculated by the vehicle state calculation unit 30. For example, the alarm control unit 40 may cause the alarm device 5 to output a main alarm when the duration of the forward gazing state is equal to or longer than a predetermined maximum allowable duration. By doing so, it is possible to prevent the forward gazing state from continuing for a long period of time, thereby suppressing the occurrence of a lane departure or the like.

(Modified example of driver state detector)
In the above-described embodiment, the driver state detection unit 20 detects that the driver of the host vehicle 1 is in a forward gazing state based on information that the driver of the host vehicle 1 is in the closed eye state. An example is shown, but the present invention is not limited to this. For example, the driver state detection unit 20 may detect that the driver of the host vehicle 1 is in a forward gazing state based on information that the driver of the host vehicle 1 is in a closed eye state or a side look state. .

DESCRIPTION OF SYMBOLS 1 Own vehicle 2 Prior vehicle 3 Driver monitoring apparatus 4 Outside vehicle monitoring apparatus 5 Alarm apparatus 10 Safety apparatus 20 Driver state detection part 30 Vehicle state calculation part 31 Own vehicle speed acquisition part 32 Leading vehicle speed acquisition part 33 Inter-vehicle distance acquisition part 34 Collision position prediction unit 35 Deceleration region calculation unit 36 Allowable region calculation unit 40 Alarm control unit

Claims (7)

A host vehicle speed acquisition unit for acquiring the speed of the host vehicle;
A preceding vehicle speed acquisition unit that acquires the speed of a preceding vehicle preceding the host vehicle;
An inter-vehicle distance acquisition unit that acquires an inter-vehicle distance between the host vehicle and the preceding vehicle;
A driver state detection unit for detecting whether or not the driver of the host vehicle is in a forward gazing state in which the driver is not gazing forward;
A collision position prediction unit that predicts a collision position at which the own vehicle collides with the preceding vehicle when it is assumed that the own vehicle does not decelerate based on at least the speed of the preceding vehicle;
A deceleration region calculating unit that calculates a deceleration time or a deceleration distance required for the speed of the host vehicle to decelerate from the speed acquired by the host vehicle speed acquiring unit to the speed of the preceding vehicle at the collision position;
Based on the inter-vehicle distance, the collision position, and the deceleration distance, an allowable area calculating unit that calculates an allowable time or an allowable distance that allows the driver of the host vehicle to be in the forward gazing state;
Comprising a safety device.   The collision position prediction unit predicts, as the collision position, a stop position of the preceding vehicle when it is assumed that the preceding vehicle starts to decelerate and stop when the driver state detection unit detects the forward gazing state. The safety device according to claim 1.   The deceleration area calculation unit includes an idle running distance calculated based on a response time of a driver of the own vehicle, a brake rising distance calculated based on a brake rising time of the own vehicle, The safety device according to claim 1, wherein the deceleration distance is calculated based on a braking distance calculated based on a deceleration.   When the duration during which the driver state detection unit continuously detects the forward gazing state is equal to or longer than the allowable time calculated by the allowable region calculation unit, an alarm device provided in the host vehicle The safety device according to any one of claims 1 to 3, further comprising an alarm control unit that outputs a main alarm.   When the duration of continuous detection of the forward gazing state by the driver state detection unit is not less than the allowable time calculated by the allowable region calculation unit and not less than a predetermined minimum duration The safety device according to any one of claims 1 to 3, further comprising an alarm control unit that outputs a main alarm to an alarm device provided in the host vehicle.   The alarm control unit is configured to detect the main alarm when a duration time during which the driver state detection unit continuously detects the forward gazing state is less than the allowable time calculated by the allowable region calculation unit. The safety device according to claim 4 or 5, wherein the alarm device is configured to output a preliminary alarm that is suppressed in comparison with the alarm device. The alarm control unit outputs a main alarm to the alarm device when a duration during which the driver state detection unit continuously detects the forward gazing state is a predetermined maximum allowable duration or more. The safety device according to any one of claims 4 to 6.

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