WO2014184991A1

WO2014184991A1 - Vehicle braking device

Info

Publication number: WO2014184991A1
Application number: PCT/JP2014/001438
Authority: WO
Inventors: 卓矢辰己
Original assignee: 株式会社デンソー
Priority date: 2013-05-14
Filing date: 2014-03-13
Publication date: 2014-11-20
Also published as: JP6011450B2; JP2014221610A

Abstract

Provided is a vehicle braking device that brakes the travel of a vehicle (1) upon detection of a decrease in the level of wakefulness of a driver as the vehicle (1) travels. The vehicle braking device is provided with: a level of wakefulness detection unit (102) that detects the level of wakefulness of the driver; a travel speed detection unit (104) that detects a travel speed of the vehicle (1); a storage unit (108) storing a brake mode of the vehicle (1) in association with the travel speed; and a braking unit (106) that brakes the travel of the vehicle (1) when the level of wakefulness is equal to or less than a predetermined threshold value, in the brake mode corresponding to the travel speed. The storage unit (108) stores the brake mode of smaller braking degree as the travel speed decreases.

Description

Vehicle braking device

Cross-reference of related applications

This application is based on Japanese Patent Application No. 2013-102084 filed on May 14, 2013, the contents of which are incorporated herein by reference.

The present disclosure relates to a vehicle braking device that detects that the driver's arousal level has decreased during traveling of the vehicle and applies braking to the traveling of the vehicle.

As part of driving assistance for the driver of the vehicle, a safe driving of the vehicle is ensured by detecting that the driver feels drowsy or that the concentration is low and alerting the driver. The technology to be developed has been developed. In addition, when the driver does not wake up due to a warning and is driving a nap, a technique has been proposed that attempts to avoid the occurrence of a collision accident by braking the running of the vehicle (Patent Document 1). Patent Document 2).

The inventor of the present application has found the following regarding the vehicle braking device. With the proposed technology, although the risk of collision of the own vehicle can be reduced by braking the running of the vehicle, there is a risk that the risk of being collided from another vehicle will increase.

Japanese Published Patent Publication No. 2008-220424 Japanese Patent Publication No. 2005-108033

The present disclosure has been made in view of the above-described problems, and when it is detected that the driver's arousal level has decreased, the vehicle can be safely braked without being collided from another vehicle. It is an object of the present invention to provide a vehicle braking device capable of performing

According to an example of the present disclosure, there is provided a vehicle braking device that detects that the driver's arousal level has decreased during traveling of the vehicle and brakes the traveling of the vehicle. The vehicle braking device stores a wakefulness detection unit that detects the driver's wakefulness, a travel speed detection unit that detects the travel speed of the vehicle, and stores the braking mode of the vehicle in association with the travel speed. And a braking unit that applies braking to the traveling of the vehicle in the braking mode according to the traveling speed when the arousal level is equal to or less than a predetermined threshold. The storage unit stores the braking mode in which the degree of braking is smaller as the traveling speed is lower.

According to such a vehicle braking device, when it is detected that the driver's arousal level has decreased, it is possible to safely brake the running of the vehicle without being collided from another vehicle.

The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings. In the attached drawings
FIG. 1 is an explanatory diagram showing the overall configuration of a vehicle equipped with a vehicle braking system, FIG. 2 is a block diagram showing a schematic structure of the control device, FIG. 3 is a flowchart of the vehicle braking process. FIG. 4 is a flowchart of the deceleration process executed during the vehicle braking process. FIG. 5 is an explanatory diagram of various patterns for decelerating the vehicle. FIG. 6 is an explanatory diagram of other aspects of various patterns for decelerating the vehicle. FIG. 7 is an explanatory diagram of various patterns for decelerating the vehicle in a modified example. FIG. 8A is an explanatory view illustrating the manner in which the vehicle is decelerated in a modified example. FIG. 8B is an explanatory diagram illustrating the manner in which the vehicle is decelerated in a modified example.

Hereinafter, examples will be described in order to clarify the contents of the present disclosure described above.
(Device configuration)
FIG. 1 shows a rough configuration of a vehicle 1 equipped with a vehicle braking system 10. As shown in the figure, the vehicle braking system 10 according to the present embodiment outputs a driver camera 20 that captures images (face images) of the face of the driver of the vehicle 1 at a certain period, and a traveling speed (vehicle speed) of the vehicle 1. A vehicle speed sensor 30, a brake actuator 42 that moves the brake pedal 40, and a control device 100 that controls the brake actuator 42 to brake the vehicle 1 are provided. The control device 100 is a known microcomputer in which a CPU, a memory, a timer, and the like are connected by a bus. The vehicle 1 is also equipped with a speaker 50 that outputs a warning sound to the driver, and the control device 100 is also connected to the speaker 50.

FIG. 2 shows a rough internal configuration of the control device 100. As shown in the figure, the control device 100 includes a wakefulness detection unit 102, a vehicle speed detection unit 104, a braking unit 106, a storage unit 108, and a warning unit 110.

These “parts” are classified for convenience in the inside of the control apparatus 100 by paying attention to the function of the control apparatus 100, and the inside of the control apparatus 100 corresponds to each “part”. It does not mean that they are physically separated. Accordingly, each “unit” can be realized as software as a part of a computer program, or can be realized as hardware using an IC chip or a large-scale integrated circuit.

When the driver camera 20 receives the driver's face image acquired by the driver camera 20 at a constant cycle, the arousal level detection unit 102 detects the driver's arousal level by analyzing the face image, and the detected arousal level is applied to the braking unit 106. And output to the warning unit 110. The vehicle speed detection unit 104 acquires the vehicle speed from the vehicle speed sensor 30 at a constant cycle, and outputs the acquired vehicle speed toward the braking unit 106. The braking unit 106 controls the braking of the vehicle 1 by operating the brake actuator 42 based on the awakening level received from the awakening level detection unit 102 and the vehicle speed received from the vehicle speed detection unit 104. The storage unit 108 stores in advance data related to a pattern for braking the vehicle 1 (corresponding to a braking mode), and the braking unit 106 reads out the pattern data stored in the storage unit 108 and stores it in the vehicle 1. The brake is to be applied. When the warning unit 110 receives the wakefulness level detected by the wakefulness level detection unit 102, the warning unit 110 determines whether or not a warning sound needs to be output and outputs a warning sound from the speaker 50.

In addition, the arousal level detection part 102 of a present Example respond | corresponds to the arousal level detection part (or means) in this invention. The vehicle speed detection unit 104 of the present embodiment corresponds to the travel speed detection unit (or means) in the present disclosure. The storage unit 108 of this embodiment corresponds to the storage unit (or means) in the present disclosure. The braking unit 106 of the present embodiment corresponds to the braking unit (or means) in the present disclosure. The control device 100 according to the present embodiment corresponds to the vehicle braking device according to the present disclosure. The driver camera 20 of the present embodiment corresponds to the photographing unit (or means) in the present disclosure. Note that the photographing unit may be included in the vehicle braking device, or may be configured as a separate body.
(Vehicle braking process)
FIG. 3 shows a flowchart of the vehicle braking process of this embodiment. This process is performed by the control device 100 of the vehicle braking system 10. In the vehicle braking process, the control device 100 first acquires a face image taken by the driver camera 20 (S100). And the control apparatus 100 detects a driver | operator's arousal level by analyzing the acquired face image (S102). Various known methods can be used to detect the arousal level. For example, the opening degree of the eye, the blink frequency, and the movement of the line of sight are detected from the driver's face image, and the control device 100 can detect the driver's arousal level based on such information. In this embodiment, it is assumed that the awakening level decreases as the driver feels sleepy or distracts, and the awakening level increases as the driver's consciousness becomes clearer.

Subsequently, the control device 100 determines whether or not the detected arousal level is equal to or less than the first threshold (S104). When the driver's consciousness is clear, the wakefulness does not fall below the first threshold value, so the control device 100 determines “no” in S104, the process returns to the top, and the control device 100 A face image is acquired from the driver camera 20 (S100).

On the other hand, when the arousal level is equal to or lower than the first threshold (S104: yes), the control device 100 determines whether the awakening level is equal to or lower than the second threshold (S106). Here, the second threshold value is set to a value smaller than the first threshold value. When the arousal level is greater than the second threshold (S106: no), the control device 100 determines that the driver's arousal level has decreased, but is not high enough to brake the vehicle 1. One warning sound is output from the speaker 50 (S108). The first warning sound is stored in advance in a memory (not shown) of the control device 100. By outputting the warning sound from the speaker 50 in this manner, it is possible to avoid a decrease in the driver's arousal level and continue driving safely. Then, after outputting the warning sound, the process returns to the top, and the control device 100 again acquires a face image from the driver camera 20 (S100), and repeats the series of processes described above.

The above describes the case where the driver's arousal level has decreased, but has not decreased to the second threshold. On the other hand, when the control device 100 determines that the driver's arousal level is equal to or lower than the second threshold (S106: yes), the control device 100 outputs the second warning sound from the speaker 50 (S110). . The second warning sound is output at a louder volume than the first warning sound so that even a driver whose awakening level has decreased can be recognized. The content of the warning of the second warning sound is also a content that strongly warns the driver of the danger. The second warning sound may be a sound for notifying that the vehicle 1 is braked. The second warning sound is also stored in advance in a memory (not shown) of the control device 100.

Then, the control device 100 determines whether or not the vehicle speed acquired from the vehicle speed sensor 30 is smaller than the stoppable speed (S112). The stoppable speed is a travel speed at which the vehicle 1 can be safely stopped. If the vehicle is stopped by applying abrupt braking in a state where the vehicle speed is high, not only a large impact is applied to the occupant of the vehicle 1 including the driver, but also a rear-end collision may occur. The stoppable speed is set as a vehicle speed at which the vehicle 1 can be safely stopped without causing such a problem, and is typically set at 20 km / h. As a result, when the control device 100 determines that the vehicle speed is higher than the stoppable speed (S112: no), a deceleration process described below is started (S200).

FIG. 4 shows a flowchart of the deceleration process performed in the vehicle braking process. In the deceleration process, first, the control device 100 determines whether or not the vehicle speed is equal to or higher than the first threshold speed (S202). The first threshold speed is a speed that becomes a threshold for determining whether or not the vehicle 1 is traveling at a relatively high speed, and is typically set to 60 km / h. As a result, when the vehicle speed is equal to or higher than the first threshold speed (S202: yes), the control device 100 determines that the vehicle 1 is traveling at a high speed, and performs a first pattern braking operation described later. (S204).

On the other hand, when the vehicle speed is smaller than the first threshold speed (S202: no), the control device 100 determines whether or not the vehicle speed is equal to or higher than the second threshold speed (S206). The second threshold speed is a speed that is a threshold for determining whether or not the vehicle 1 is traveling at a standard speed, and is typically set to 40 kilometers per hour. As a result, if the vehicle speed is smaller than the first threshold speed but greater than or equal to the second threshold speed (S206: yes), the control device 100 determines that the vehicle 1 is traveling at a standard speed, The control device 100 performs the second pattern braking operation (S208). On the other hand, when the vehicle speed is lower than the second threshold speed (S206: no), the control device 100 determines that the vehicle 1 is traveling at a relatively low speed although it is higher than the stoppable speed. The control device 100 performs the third pattern braking operation (S210).

FIG. 5 illustrates various patterns for decelerating the vehicle 1. In the first pattern, the brake actuator 42 is operated to depress the brake pedal 40 for a time T1, and then a braking operation is performed to hold the depressed state for a time t1. Here, it is assumed that the amount of depression does not change while the brake pedal 40 is depressed. In the braking operation of this embodiment, after the brake pedal 40 is depressed for the time T1, the operation of holding the state where the depression is released for the time t1 is performed once. This operation may be repeated a plurality of times (for example, three times).

In contrast, in the second pattern, the time during which the brake pedal 40 is depressed is shortened from the time T1 to the time T2 as compared with the first pattern. The time for releasing the depression is extended from time t1 to time t2. Further, in the third pattern, the time during which the brake pedal 40 is depressed is shortened from time T2 to time T3 as compared to the second pattern. Then, the time for releasing the depression is extended from time t2 to time t3. In this embodiment, the time required for one braking operation is set to be the same in any pattern, and accordingly, the total time of time T1 and time t1, the total time of time T2 and time t2, The total time of time T1 and time t1 is the same. In any pattern, the depression amount of the brake pedal 40 is the same.

In the deceleration process shown in FIG. 4, after the control device 100 performs a braking operation of any pattern according to the vehicle speed of the vehicle 1 (S204, S206, S210), the deceleration process is terminated and the vehicle of FIG. Return to the braking process. Then, after returning from the deceleration process, the process returns to the beginning of the vehicle braking process, and the control device 100 acquires a face image from the driver camera 20 again (S100), and starts the series of processes described above.

When the vehicle speed of the vehicle 1 is reduced to a stoppable speed by repeating such processing (S112: yes), the control device 100 operates the brake actuator 42 while turning on the hazard lamp (not shown) to turn on the brake pedal 40. The vehicle 1 is stopped by stepping on (S114), and the vehicle braking process of FIG. 3 is terminated. Further, while the vehicle speed of the vehicle 1 is decelerated to the stoppable speed, the control device 100 detects the driver's arousal level and compares the arousal level with the first threshold value and the second threshold value (S100, S102, S104, S106). Therefore, when the driver wakes up while the vehicle 1 is decelerating, the deceleration process is stopped.

In the vehicle deceleration process described above, the driver's arousal level has decreased below the second threshold value. However, if the vehicle speed of the vehicle 1 exceeds the stoppable speed, the control device 100 performs the deceleration shown in FIG. The vehicle is stopped after the vehicle 1 is decelerated by performing the process. In the deceleration process, the vehicle 1 is decelerated with a pattern corresponding to the vehicle speed. For this reason, the vehicle 1 can be safely stopped after decelerating the vehicle 1 safely without being collided with the following vehicle. Hereinafter, this point will be described in detail.

As described above with reference to FIG. 5, the time for which the brake pedal 40 is depressed is shortened as the vehicle speed of the vehicle 1 decreases, and accordingly, the degree of braking of the vehicle 1 is set to be small. This is because if the vehicle is braked when the vehicle speed is low, the vehicle 1 is decelerated suddenly, and there is a possibility that the vehicle 1 may collide with the following vehicle. However, when the vehicle 1 is traveling at a relatively high speed, the vehicle 1 does not decelerate suddenly even if a large amount of braking is applied (unless extremely large braking is applied). Rather, if the vehicle is not braked to a certain extent, the vehicle 1 may take too long to decelerate. Therefore, the vehicle braking system 10 according to the present embodiment is set so that as the vehicle speed of the vehicle 1 increases, the time that the brake pedal 40 is depressed is lengthened and large braking can be applied. As a result, it is possible to quickly decelerate the vehicle 1 to the stoppable speed, and it is possible to safely stop the vehicle 1 without causing the possibility of a rear-end collision with the following vehicle.

When detecting the degree of arousal from the face image (corresponding to S102 in FIG. 3), if the driver's eyes are closed continuously for a certain period of time (for example, 2 to 3 seconds), it will be detected so far. Regardless of the value of the arousal level, the small arousal level equal to or less than the second threshold may be immediately used. In this way, even if the driver suddenly feels strong sleepiness while driving the vehicle 1, the vehicle 1 can be immediately decelerated and stopped safely.

In the above-described embodiment, the brake actuator 42 is operated to change the time for which the brake pedal 40 is depressed, thereby changing the degree of braking of the vehicle 1. However, as long as the degree of braking can be varied, it is not necessarily limited to changing the depression time of the brake pedal 40. For example, the degree of braking may be varied by changing the amount of depression of the brake pedal 40.

FIG. 6 illustrates a case where the degree of braking is varied by changing the depression amount of the brake pedal 40. In the illustrated first pattern, the brake pedal 40 is depressed with the depression amount P1 for the time T0, and then the braking operation is performed to maintain the depression released state for the time t0. In the second pattern and the third pattern, the time T0 when the brake pedal 40 is depressed and the time t0 when the depression is released are the same as those in the first pattern, but the depression amount decreases to P2 in the second pattern. However, in the third pattern, it decreases to P3. Even in this case, when the vehicle 1 is traveling at a relatively high speed, the vehicle speed of the vehicle 1 is quickly decelerated by applying large braking, and the degree of braking is reduced when the vehicle speed decreases. Thus, the vehicle 1 can be stopped without causing the possibility of a rear-end collision with the following vehicle. Of course, the present invention is not limited to the patterns illustrated in FIGS. 5 and 6, and the degree of braking may be varied by changing the depression time and depression amount of the brake pedal 40.
(Modification)
In the embodiment described above, the braking operation has been described as being performed exclusively for safely decelerating the vehicle 1. However, the braking operation of the vehicle 1 may be used to awaken the driver in addition to the deceleration of the vehicle 1.

FIG. 7 illustrates a braking operation used in a vehicle braking system 10 according to a modified example. As shown in the figure, in the modification, for each of the first pattern, the second pattern, and the third pattern, two types of braking operations are set, that is, a braking operation at the first braking and a braking operation at the second and subsequent braking. Has been. The second and subsequent braking operations are the same as the braking operation of the present embodiment described above with reference to FIG. That is, the amount of depression of the brake pedal 40 is constant, and the degree of braking is changed by varying the depression time.

On the other hand, at the time of the first braking, in any pattern, the braking operation is performed by depressing the brake pedal 40 momentarily for a short time. That is, in any of the first pattern, the second pattern, and the third pattern, the depression time of the brake pedal 40 is set to a short time T4, and the depression amount is set for the second and subsequent braking. It is set to a larger depression amount. Furthermore, when the amount of depression at the time of initial braking of each pattern is compared, the amount of depression of the first pattern is the largest, and a smaller amount of depression is set as the second pattern and the third pattern are reached.

FIG. 8A and FIG. 8B illustrate how the vehicle 1 is decelerated by the vehicle braking system 10 according to the modified example. FIG. 8A shows a case where the braking operation is started from the first pattern because the vehicle speed at the start of braking is larger than the first threshold speed. FIG. 8B shows a case where the braking operation is started from the second pattern because the vehicle speed at the start of braking is smaller than the first threshold speed but larger than the second threshold speed. In any case, the first brake operation is instantaneous and stronger than the second and subsequent brake operations.

As described above, in the modified example, in the first braking operation, a stronger braking operation is instantaneously performed, so that the vehicle 1 moves differently from the moment. This movement acts to surprise the driver and restore the reduced alertness. As a result, if the driver's arousal level recovers to a normal level, the vehicle 1 can continue to travel.

In the above-described modification, it has been described that the operation of momentarily stepping on the brake pedal 40 is performed in the first braking operation. Accordingly, even when the braking operation of the first pattern is switched to the second pattern and the third pattern as the vehicle 1 decelerates, only the first braking operation of such a series of braking operations is normally performed. Unlike the above description, it is assumed that the operation of depressing the brake pedal 40 for a short time is performed. However, in the first braking operation after switching from the first pattern to the second pattern and the first braking operation after switching from the second pattern to the third pattern, the brake operation different from normal is performed. Also good. This makes it possible to surprise the driver even during deceleration of the vehicle 1 and obtain an opportunity to recover the awakening level.

As mentioned above, although the present Example and modification were demonstrated, this indication is not restricted to said Example and modification, It can implement in a various aspect in the range which does not deviate from the summary.

When the vehicle braking apparatus according to an example of the present disclosure detects that the driver's arousal level has dropped below a threshold value, the vehicle braking device reads the braking mode stored according to the traveling speed of the vehicle and brakes the traveling of the vehicle. Call. The braking mode stored in advance is a mode in which the degree of braking is smaller as the traveling speed of the vehicle is lower.

When the vehicle traveling speed is high, the vehicle cannot be quickly decelerated unless a certain amount of braking is applied. However, if a large amount of braking is applied when the traveling speed is low, the traveling speed will drop rapidly, and there is a risk of a rear-end collision from the following vehicle. Therefore, a braking mode is stored in advance so that the degree of braking decreases as the traveling speed of the vehicle decreases. And when a driver | operator's arousal level falls, if the braking mode memorize | stored according to driving speed is read and a vehicle is braked, a vehicle will be decelerated rapidly, without being collided from another vehicle. Is possible.

In the vehicle braking device of the present disclosure described above, the vehicle travels by braking the vehicle for a predetermined braking time corresponding to the traveling speed and then releasing the braking. It is good also to apply. And as a braking mode, it is good also as memorize | storing short braking time, so that driving speed becomes low.

The degree of braking can be changed by changing the braking strength instead of the braking time. However, if the degree of braking is changed by the braking time, it is irrelevant even if the degree of braking is increased. There is no need to apply braking. Therefore, it is possible to safely brake the running of the vehicle without giving an impact to the vehicle.

In the vehicle braking device of the present disclosure described above, the degree of arousal is detected by capturing an image of the driver's face (face image) and extracting the driver's eyes from the face image. Also good. When the extracted driver's eyes are closed, the degree of arousal may be determined to be equal to or less than the threshold value, and braking of the vehicle may be applied.

In this way, even when the driver is suddenly attacked by strong sleepiness, the vehicle can be immediately braked.

As mentioned above, although embodiment and a structure concerning this indication were illustrated, an embodiment and a composition concerning this indication are not limited to each embodiment and each composition mentioned above. Embodiments and configurations obtained by appropriately combining technical elements disclosed in different embodiments and configurations are also included in the scope of the embodiments and configurations according to the present disclosure.

Claims

A vehicle braking device that detects that the driver's arousal level has decreased during traveling of the vehicle (1) and brakes the traveling of the vehicle (1),
An arousal level detection unit (102) for detecting the driver's arousal level;
A travel speed detector (104) for detecting the travel speed of the vehicle (1);
A storage unit (108) storing a braking mode of the vehicle (1) in association with the traveling speed;
A braking unit (106) for braking the traveling of the vehicle (1) in the braking mode according to the traveling speed when the arousal level is equal to or less than a predetermined threshold;
The storage unit (108) is a vehicle braking device that stores the braking mode in which the degree of braking is smaller as the traveling speed is lower.
The vehicle braking device according to claim 1,
When the arousal level is equal to or less than the threshold, the braking unit (106) brakes the travel of the vehicle (1) for a predetermined braking time corresponding to the travel speed, and then performs the braking. Repeat the release action,
The said memory | storage part (108) is a vehicle braking device which memorize | stores the said braking time short, so that the said traveling speed becomes low as the said braking aspect.
The vehicle braking device according to claim 1 or 2,
A photographing unit (20) for photographing an image of the driver's face;
The arousal level detection unit (102) detects the arousal level by extracting the driver's eyes from an image of the driver's face,
The braking unit (106) is a vehicle braking device that applies braking to travel of the vehicle (1) by determining that the arousal level is equal to or less than the threshold when the eyes of the driver are closed.