JP6940337B2 - On-board unit and sudden deceleration event detection method - Google Patents

Description

The present invention relates to an on-board unit and a sudden deceleration event detection method.

For example, in a company that manages the operation of trucks, buses, taxi vehicles, etc., it is necessary to ensure the safety of vehicle operation. Therefore, for example, it is necessary to issue a warning to a driver who is operating a vehicle for a high-risk driving operation, or to provide guidance and education for safe driving to a specific crew member who repeats a high-risk driving operation. There is. Therefore, it is necessary for the managers and the like in the company to collect information on high-risk driving operations for each crew member and grasp the actual driving situation.

For example, an in-vehicle device such as a drive recorder or a digital tachograph mounted on a commercial vehicle may have a function of collecting and recording information on a high-risk driving operation. Therefore, by using such an on-board unit, the manager or the like can collect information necessary for managing the crew and grasp the driving situation.

For example, the drive recorder shown in Patent Document 1 can promptly know the occurrence of an accident and the scale of an accident, and shows a technique for improving immediacy. Specifically, when a G value exceeding the threshold value is input, a predetermined time elapses until the G value detected by the G sensor subsequently reaches the value 0 or after the threshold value is exceeded. Wait until, and search for the maximum value Gmax of the G value. When the maximum value Gmax of the G value is found, the image data at this time is extracted from the image data recorded in the memory and transmitted to the data management device on the office side by wireless communication.

Further, the driving support system of Patent Document 2 shows a technique for collecting information not only when an accident occurs but also for the purpose of safe driving guidance, and also for reducing the burden on the administrator side. Specifically, the on-board unit buffers the acceleration and speed of the vehicle and the peripheral image of the vehicle to acquire the acceleration. Then, it is determined whether or not the acceleration is at the notification level, and if it is at the notification level, the vehicle behavior information is transmitted to the outside. In Patent Document 2, whether or not to notify is determined only by the level of acceleration.

Japanese Unexamined Patent Publication No. 2013-175032 Japanese Unexamined Patent Publication No. 2014-75035

For example, by using technologies such as Patent Document 1 and Patent Document 2, abnormal behavior such as sudden deceleration of a moving vehicle is detected as a special event, and data at the corresponding timing is recorded or data is recorded. It can be sent to the outside. Further, an event such as a sudden deceleration of a vehicle is detected by the magnitude of the acceleration, and the G value output by the G sensor is usually adopted for this acceleration (see Patent Document 1).

On the other hand, since the acceleration in the front-rear direction of the vehicle corresponds to the time derivative value of the vehicle speed, it is possible to obtain the acceleration by calculation based on the vehicle speed information. Vehicles are generally equipped with a speed sensor that outputs a pulse signal in conjunction with a certain amount of rotation of the wheels, so the actual vehicle speed (km / h) is used using this pulse signal (vehicle speed signal). ), And further differentiated to calculate the acceleration.

When detecting abnormal behavior such as sudden deceleration of a moving vehicle by comparing it with a threshold value, it is usually obtained by differentiating the vehicle speed rather than judging by the magnitude of the G value output by the G sensor. Judgment accuracy tends to be higher when the magnitude of the acceleration to be performed is determined.

However, when the determination is made based on the magnitude of the acceleration obtained by differentiating the vehicle speed, an erroneous determination is likely to occur in the special environment of the vehicle as shown in (1) to (3) below.
(1) For example, when the vehicle starts from a stopped state on a snowy road, the vehicle starts slowly after the tires slip and slip, so the vehicle speed detected by the speed sensor is shown in FIG. 7, for example. Anomalous changes appear as shown. Therefore, when the acceleration is calculated by differentiating this vehicle speed, an abnormal change is detected as a large acceleration. As a result, it is erroneously determined as an event of sudden deceleration even though it is a mere starting operation of the vehicle.

(2) For example, if the brake is applied while the vehicle is traveling on a rainy road, the tires temporarily lock due to slip and then return to the normal state. Therefore, for example, the vehicle speed detected by the speed sensor. Anomalous changes as shown in FIG. 8 appear. Therefore, when the acceleration is calculated by differentiating this vehicle speed, an abnormal change is detected as a large acceleration. As a result, it is erroneously determined as a sudden deceleration event even though it is a normal braking operation of the vehicle.

(3) Depending on the type of vehicle, a special speed pulse may be generated to move the speedometer when the engine is started for the purpose of producing an effect of the speedometer or the like. When the acceleration is calculated using the speed signal including this special speed pulse, it may be erroneously determined as a sudden deceleration event even though the sudden deceleration operation is not performed.

The present invention has been made in view of the above circumstances, and an object of the present invention is to enable highly accurate determination of an event representing an abnormal behavior such as sudden deceleration of a vehicle and prevent erroneous determination. It is an object of the present invention to provide an in-vehicle device and a method for detecting a sudden deceleration event.

In order to achieve the above-mentioned object, the vehicle-mounted device and the sudden deceleration event detection method according to the present invention are characterized by the following (1) to (2).
(1) A speed signal acquisition unit that acquires a speed signal generated in conjunction with the rotation of the wheels of the vehicle from a vehicle speed sensor that detects the rotation of the wheels.
A G value acquisition unit that acquires a G value indicating the magnitude of acceleration applied to the vehicle from an acceleration sensor mounted on the vehicle, and a G value acquisition unit.
An event detection unit that detects an event related to sudden deceleration of the vehicle based on a determination condition that combines the speed change rate calculated from the speed signal and the G value.
An imaging device that captures at least one of the inside and outside of the vehicle,
When the event is detected, an event processing unit that transmits an image captured by the photographing device to a predetermined external device in the vicinity of the time when the event occurs , and an event processing unit.
Equipped with a,
The G value acquisition unit has a G value history holding unit capable of holding a plurality of the G values detected at different timings.
The event detection unit has a plurality of G values held in the G value history holding unit in a range from the current time before a predetermined time to the present when the current rate of change in speed exceeds a predetermined threshold value. An event related to a sudden deceleration of the vehicle is detected based on the fact that one or more of the G values exceed a predetermined second threshold value.
An in-vehicle device characterized by that.

( 2 ) For the on-board unit mounted on the vehicle
The speed signal generated in synchronization with the rotation of the wheels of the vehicle is acquired from a vehicle speed sensor for detecting the rotation of the wheel,
The G value representing the magnitude of the acceleration applied to the vehicle is acquired from the acceleration sensor mounted on the vehicle,
A speed change ratio calculated the velocity signal or al, based on the determination condition combining with the G values, to detect events related to the rapid deceleration of the vehicle,
When the event is detected, sudden deceleration event detection causes a predetermined external device to transmit an image captured by a photographing device that images at least one of the inside and the outside of the vehicle in the vicinity of the time when the event occurs. It ’s a method,
In the in-vehicle device
A plurality of the G values detected at different timings are held in the G value history holding unit.
One or more of the plurality of G values held in the G value history holding unit in the range from the current time before the predetermined time to the present when the current rate of change in speed exceeds a predetermined threshold value. Based on the fact that the G value exceeds a predetermined second threshold value, an event related to the sudden deceleration of the vehicle is detected.
A sudden deceleration event detection method characterized by this.

According to the on-board unit having the configuration of (1) above, since the event related to the sudden deceleration is detected based on the speed change rate calculated from the speed signal, highly accurate determination becomes possible. Moreover, by using the G value indicating the magnitude of the acceleration applied to the vehicle, it is possible to suppress erroneous determination due to wheel slip.

Further, according to the in-vehicle device having the configuration of ( 1 ) above, when an event unrelated to sudden deceleration such as wheel slip occurs, the image captured by the photographing device is suppressed from being transmitted to the external device. Only images with high utility value can be transmitted to an external device.

Furthermore, according to the in-vehicle device having the configuration of (1 ) above, by using the history of the G value, for example, the maximum value of the acceleration applied to the vehicle can be grasped, so that an event related to sudden deceleration has occurred? Whether or not it can be determined more reliably. Therefore, for example, when an event unrelated to sudden deceleration occurs, it is possible to suppress transmission of low utility value video to an external device.

Furthermore, according to the on-board unit having the configuration of (1 ) above, the event related to the sudden deceleration of the vehicle is determined by using the combination of the magnitude of the speed change rate and the conditions of a plurality of G values, so that the accuracy is high. Can be determined. Moreover, it is possible to reduce erroneous determination even in a special environment where wheel slippage is likely to occur. Therefore, for example, when an event unrelated to sudden deceleration occurs, it is possible to more accurately distinguish a highly useful image to be transmitted to an external device.

According to the sudden deceleration event detection method having the configuration of (2 ) above, an event related to sudden deceleration is detected based on the speed change rate calculated from the speed signal, so that highly accurate determination is possible. Moreover, by using the G value indicating the magnitude of the acceleration applied to the vehicle, it is possible to suppress erroneous determination due to wheel slip.

According to the on-board unit and the sudden deceleration event detection method of the present invention, it is possible to determine with high accuracy an event representing an abnormal behavior such as sudden deceleration of a vehicle, and to prevent erroneous determination. That is, since the event related to the sudden deceleration is detected based on the speed change rate calculated from the speed signal, highly accurate determination becomes possible. Moreover, by using the G value indicating the magnitude of the acceleration applied to the vehicle, it is possible to suppress erroneous determination due to wheel slip.

The present invention has been briefly described above. Further, the details of the present invention will be further clarified by reading through the embodiments described below (hereinafter referred to as "embodiments") with reference to the accompanying drawings. ..

FIG. 1 is a block diagram showing a configuration example of an operation management system. FIG. 2 is a time chart showing an example-1 of the relationship between the acceleration detected by the velocity pulse, the G value detected by the sensor, and the determination operation of the on-board unit. FIG. 3 is a schematic view showing a specific example-1 of the configuration of the acceleration table and the contents to be held. FIG. 4 is a time chart showing Example 2 of the relationship between the acceleration detected by the velocity pulse, the G value detected by the sensor, and the determination operation of the on-board unit. FIG. 5 is a schematic view showing a specific example-2 of the configuration of the acceleration table and the contents to be held. FIG. 6 is a flowchart showing an operation example of the on-board unit for determining a sudden deceleration event. FIG. 7 is a graph showing an example of a speed change detected based on a speed pulse when the vehicle starts on a snowy road. FIG. 8 is a graph showing an example of a speed change detected based on a speed pulse when a vehicle brakes while traveling on a rainy road.

Specific embodiments of the present invention will be described below with reference to the respective figures.

<System configuration>
A configuration example of the operation management system is shown in FIG.

The operation management system of this embodiment is introduced as equipment of a business operator such as a trucking company or a bus company. The operation management system 5 manages the operation status of vehicles such as trucks and buses, and includes a drive recorder 10 and an office PC 30 mounted on each vehicle as an on-board unit. The drive recorder 10 of each vehicle is connected to the office PC 30 via a wireless communication line and a network 70.

The office PC 30 is composed of a general-purpose computer device (PC) installed in the office, and manages the operation status of the vehicle. The network 70 is a packet communication network such as the Internet to which a radio base station 8 and an office PC 30 that perform wide area communication with the drive recorder 10 are connected, and relays data communication performed between the drive recorder 10 and the office PC 30. .. Communication between the drive recorder 10 and the wireless base station 8 may be performed by a mobile communication network (mobile line network) such as LTE (Long Term Evolution) / 4G (4th Generation), or a wireless LAN (Local Area). Network) may be used.

The drive recorder 10 is mounted on the vehicle and transmits operation data and image data to the office PC 30 as needed. The drive recorder 10 includes a CPU 11, a speed I / F (interface) 12A, an engine rotation I / F12B, an external input I / F13, a sensor input I / F14, a GPS receiver 15, a camera I / F16, a non-volatile memory 26A, and a volatile memory. It has 26B, a recording unit 17, a card I / F18, a voice I / F19, an RTC (clock IC) 21, a SW input unit 22, a display unit 27, an acceleration table TB1, a communication unit 24, and a power supply unit 25.

The CPU 11 comprehensively controls each part of the drive recorder 10 by executing a predetermined program. In the present embodiment, the CPU 11 is provided with a function of a determination unit 11a that detects a predetermined event such as a sudden deceleration of the vehicle.

The CPU 11 monitors the speed pulse signal SG1 output by the vehicle speed sensor 51 provided on the vehicle side via the speed I / F12A, thereby monitoring the current vehicle speed (km / h), mileage, and vehicle speed change rate (front-rear direction). (Equivalent to the acceleration of) etc. can be grasped.

The vehicle speed sensor 51 detects the rotation of the wheels of the vehicle and outputs one pulse as the speed pulse signal SG1 each time the wheels rotate by a predetermined amount. Therefore, for example, it is possible to detect the current vehicle speed based on the number of pulses of the speed pulse signal SG1 generated within a certain period of time. In addition, the mileage of the vehicle can be grasped based on the cumulative value of the number of pulses. It is also possible to detect the amount of change in vehicle speed within a certain period of time as the acceleration applied in the front-rear direction of the vehicle. However, when slip occurs between the wheels and the road surface, a large error occurs between the vehicle speed calculated from the speed pulse signal SG1 and the actual traveling speed of the vehicle. Therefore, when slip occurs, an error also occurs in the acceleration calculated from the vehicle speed.

The G sensor 28 mainly detects a shocking acceleration (G value) applied in the front-rear direction of the own vehicle. Specific examples of the G sensor 28 include a method of reading mechanical displacement due to acceleration as vibration and a method of reading optically, and it is assumed that an appropriate method is adopted as necessary. .. A plurality of G sensors 28 may be used, or G values in the lateral direction may be detected in addition to the front-rear direction. The CPU 11 can read the G value in the vehicle front-rear direction from the signal of the G sensor output SG2 via the sensor input I / F14. This G value can be used as an acceleration that is not affected by wheel slip.

The non-volatile memory 26A is used to store an operation program executed by the CPU 11, predetermined constant data, and the like. The volatile memory 26B is used to temporarily hold various data.

The recording unit 17 is a dedicated hardware circuit having a function of periodically recording data such as operation data and video in a predetermined storage area. A memory card 65 owned by the crew is freely inserted and removed from the card I / F18. The CPU 11 writes and saves data such as operation data and video to the memory card 65 connected to the card I / F18.

The acceleration table TB1 is a storage area used for managing various data related to acceleration. The acceleration table TB1 is arranged in any of the internal memory of the CPU 11, the non-volatile memory 26A, and the volatile memory 26B, for example. A specific example of the acceleration table TB1 will be described later.

The voice I / F 19 has a function of generating a synthesized voice signal. A built-in speaker 20 is connected to the output of the voice I / F19. The speaker 20 emits a sound such as an alarm. The RTC21 (timekeeping unit) measures the current time. ON / OFF signals of various buttons such as a warehousing button and a warehousing button are input to the SW input unit 22. The display unit 27 is composed of an LCD (Liquid Crystal Display) and displays not only communication and operation status but also alarms and the like.

A rotation pulse from an engine rotation speed sensor (not shown) is input to the engine rotation I / F12B. An external device (not shown) is connected to the external input I / F13. Signals such as a temperature sensor (not shown) for detecting the engine temperature (cooling water temperature) and a fuel amount sensor (not shown) for detecting the fuel amount are input to the analog input I / F29 as needed.

The GPS receiving unit 15 is connected to the GPS antenna 15a, receives a signal transmitted from a GPS satellite, and acquires a current position (GPS position information).

An in-vehicle camera (imaging device) 23 for capturing image data around the vehicle (for example, in front) and acquiring image data is connected to the camera I / F16. The in-vehicle camera 23 has, for example, an image sensor in which 300,000 pixels, 1 million pixels, and 2 million pixels are arranged on an imaging surface imaged through a fisheye lens. The image sensor is composed of known sensors such as a CMOS (complementary metal oxide semiconductor) sensor and a CCD (charge-coupled device) sensor.

The video (image data) captured by the vehicle-mounted camera 23 is recorded in the storage area in the recording unit 17 in chronological order, but is repeatedly overwritten so as to be recorded for a predetermined time. This predetermined time is, for example, a time corresponding to several seconds (for example, 2 seconds, 4 seconds, 10 seconds, etc.) before and after the accident so that the situation of the accident can be understood at the time of the accident. The image captured by the in-vehicle camera 23 may be a still image or a moving image. The images before and after the accident are displayed on the display unit 33 of the office PC 30, as will be described later.

Further, the in-vehicle camera 23 may be provided in plurality so as to be able to image not only the front of the vehicle but also the rear, left side, and right side of the vehicle, or a plurality of image sensors for capturing each direction may be provided. It may be housed in a housing. Therefore, the in-vehicle camera 23 can simultaneously capture the image in the left-right direction and the image in the rear in addition to the image in front of the vehicle.

When the communication unit 24 performs wide area wireless communication and is connected to the wireless base station 8 via the mobile network (mobile communication network), the office PC 30 is connected to the wireless base station 8 via a network 70 such as the Internet. Secure a line with and communicate with. The power supply unit 25 supplies electric power to each unit of the drive recorder 10 by turning on the ignition switch or the like.

Further, when the drive recorder 10 detects the occurrence of a predetermined event indicating an abnormality such as a sudden deceleration of the own vehicle, the drive recorder 10 uses wireless communication to perform data such as images taken by the in-vehicle camera 23 for a certain period of time, for example. It is transmitted to the PC30. As a result, the manager or the like on the office PC30 side can surely and in real time grasp the image when an important event such as a sudden deceleration occurs. Further, since the office PC 30 stores only the image when an important event occurs, the storage capacity can be reduced. In addition, by transmitting large-capacity video data only when an event occurs, it is possible to suppress an increase in network traffic and reduce communication costs.

The determination unit 11a in the CPU 11 detects the occurrence of a special event such as a sudden deceleration of the vehicle, and at the time of this determination, the speed change rate (acceleration) detected based on the speed pulse signal SG1 and the speed change rate (acceleration). Both the G value corresponding to the G sensor output SG2 are referred to. This makes it possible to improve the determination accuracy and prevent erroneous determination. Details will be described later.

On the other hand, the office PC 30 is composed of PCs operating on a general-purpose operating system. The office PC 30 functions as an operation management device and has a CPU 31, a communication unit 32, a display unit 33, a storage unit 34, a card I / F35, an operation unit 36, an output unit 37, a voice I / F38, and an external I / F48. ..

The CPU 31 comprehensively controls each part of the office PC 30. The communication unit 32 can communicate with the drive recorder 10 via the network 70. Further, the communication unit 32 can also connect to various databases (not shown) connected to the network 70, and can acquire necessary data.

The display unit 33 displays an accident image, a hazard map, and the like in addition to the operation management screen. The storage unit 34 stores various programs such as system analysis software for displaying the image received from the drive recorder 10 and displaying the position information of the vehicle on the map.

A memory card 65 is freely inserted and removed from the card I / F35. The card I / F35 inputs the operation data measured by the drive recorder 10 and stored in the memory card 65. The operation unit 36 has a keyboard, a mouse, and the like, and accepts operations by an office manager. The output unit 37 outputs various data. A microphone 41 and a speaker 42 are connected to the voice I / F 38. The office manager can also make a voice call using the microphone 41 and the speaker 42, and when a vehicle accident occurs, he / she contacts the emergency department or the police.

An external storage device (storage memory) 54 is connected to the external I / F 48. The external storage device 54 holds the accident point database (DB) 55, the operation data DB 56, and the hazard map DB 57. The GPS position information (latitude, longitude) of the vehicle at the time of the accident, which is transmitted from the drive recorder 10 or another on-board unit, is registered in the accident point database (DB) 55. In the operation data DB 56, in addition to the entry / exit time, speed, mileage, etc., sudden acceleration / deceleration, sudden steering wheel, speed over, engine speed over, etc. are recorded as operation data. In the hazard map DB 57, map data in which a mark indicating a point (accident point) where an accident occurred in the past is superimposed on the map is registered. In this hazard map, areas where disasters such as natural disasters are expected, evacuation sites, etc. may be described.

When the CPU 31 reads out the hazard map of the area designated from the hazard map DB 57 (for example, the area including the accident point) and displays it on the display unit 33, the CPU 31 acquires the data of the accident point registered in the accident point DB 55 and causes the hazard. A new hazard map is generated by superimposing marks representing these accident points on the map. Office managers can instantly see the latest accident locations on a map.

On the other hand, in a high-risk driving situation where the driver feels a smirk or a hat while the vehicle is in operation, the driver often performs a sudden braking operation. That is, the vehicle suddenly decelerates. Therefore, if the manager can confirm information such as an image taken by the in-vehicle camera 23 in real time when the vehicle suddenly decelerates, the manager can accurately grasp the driving situation of the vehicle. This makes it possible to instruct and educate a specific driver who repeatedly performs a high-risk driving operation to drive safely.

The drive recorder 10 shown in FIG. 1 can automatically detect an event representing the behavior of the vehicle such as sudden deceleration, and when the event occurs, the image of the in-vehicle camera 23 is displayed in real time by wireless communication. It can be transmitted to the PC30. Instead of transmitting by wireless communication, the relevant important video data may be stored in the memory card 65. The CPU 11 is provided with a function of determining the behavior of the vehicle such as sudden deceleration as the determination unit 11a. The determination unit 11a performs a special determination process as described later in order to improve the accuracy of the determination and prevent an erroneous determination. The determination unit 11a is incorporated into the drive recorder 10 as a program that can be executed by the CPU 11, for example.

<Example of vehicle behavior and sudden deceleration judgment operation-1>
Example of the relationship between the acceleration VA1 (km / h / s) detected by the speed pulse signal SG1 and the time-dependent change of the G value VA2 in the vehicle front-rear direction detected by the G sensor 28 and the determination operation in the drive recorder 10- 1 is shown in FIG.

The example shown in FIG. 2 shows a situation in which the vehicle actually suddenly decelerates due to the driver's braking operation. Therefore, from the timing before the time tb, a large change in the acceleration VA1 occurs in the negative direction, and a large change also occurs in the G value VA2. That is, by simultaneously monitoring the behavior of both the acceleration VA1 and the G value VA2, it is possible to determine whether or not the vehicle has suddenly decelerated.

Actually, in consideration of the determination accuracy, as the first determination condition, it is determined whether or not the acceleration VA1 has a sudden deceleration behavior by comparing the acceleration VA1 with the predetermined determination threshold value TH1. Part 11a identifies. In the example of FIG. 2, it is detected that the acceleration VA1 exceeds the determination threshold value TH1 at the timing of time ta.

However, under special circumstances such as wheel slippage, the acceleration VA1 calculated from the velocity pulse signal SG1 may contain a large error. Therefore, in order to prevent erroneous determination, the determination unit 11a uses the result of comparing the G value VA2, which is not affected by wheel slip, and the predetermined threshold value TH2, as the second determination condition.

In the state of FIG. 2, since the G value VA2 exceeds the threshold value TH2 before the time ta when it is detected that the acceleration VA1 exceeds the determination threshold value TH1, sudden deceleration actually occurs. Can be determined. However, at time ta, the G value VA2 is attenuated and has already fallen below the threshold value TH2. Therefore, when determining the G value VA2, it is necessary to refer to the behavior of the G value VA2 that occurred before the time ta.

For example, if the G value VA2 exceeds the threshold value TH2 between the time ta and the time tb one second (s) before that, even for a very short time, not only the acceleration VA1 but also the acceleration VA1 , It can be considered that the behavior associated with the sudden deceleration also occurred in the G value VA2.

In the example shown in FIG. 2, the determination unit 11a of the drive recorder 10 detects that the acceleration VA1 exceeds the determination threshold value TH1 at the time ta, and considers that “the image transmission determination is valid” (step S01). Further, the determination unit 11a detects that the G value VA2 within the range of time ta to tb exceeds the threshold value TH2, and transmits an image (step S02).

In order for the determination unit 11a to perform the operation shown in FIG. 2, it is necessary to refer to the G value VA2 at the time ta when the acceleration VA1 is detected to be abnormal and before that time. Therefore, the acceleration table TB1 is used.

<Structure example-1 of acceleration table TB1>
FIG. 3 shows a specific example-1 of the configuration of the acceleration table TB1 and the contents to be retained. The content of the acceleration table TB1 shown in FIG. 3 represents the data of the situation corresponding to the change with time of the acceleration VA1 and the G value VA2 shown in FIG. Further, as will be described later, the contents of the acceleration table TB1 are updated periodically.

As shown in FIG. 3, the acceleration table TB1 includes items of the time management area TB1a, the velocity storage area TB1b, the acceleration storage area TB1c, and the G value storage area TB1d.

The time management area TB1a is provided to manage the difference in the time when each of the held data is detected. For example, each data detected at each time t2, t1, t0, t-1, t-2, ..., T-9, t-10, t-11 every 0.1 seconds is shown in the acceleration table TB1. It is held at the position of the corresponding line. Further, as shown in FIG. 3, when an alarm is generated at the timing of time t0, 0.2, 0.1, 0, -0.1, -0.2, -representing the time difference with respect to the position at time t0. 0.3, ..., -0.9, -1.0, -1.1 (seconds: s) are managed in each line of the time management area TB1a. This alarm corresponds to the time ta situation (-VA1> TH1) shown in FIG.

The speed storage area TB1b holds the value of the vehicle speed (km / h) at each time every 0.1 seconds calculated based on the speed pulse signal SG1. The acceleration storage area TB1c holds the vehicle acceleration (km / h / s) calculated based on the vehicle speed of the speed storage area TB1b, that is, the value of the acceleration VA1 in FIG. 2 every 0.1 seconds. The G value storage area TB1d holds the G value in the vehicle front-rear direction corresponding to the G sensor output SG2, that is, the value of the G value VA2 shown in FIG. 2 every 0.1 seconds.

The determination unit 11a compares the acceleration VA1 in the acceleration storage area TB1c with the determination threshold value TH1 at the timing of time t0 in FIG. When it detects that it has become, it processes as follows. That is, with reference to this time t0 (= ta), the G value VA2 of the G value storage area TB1d of the reference range A1 up to the time t-9 0.9 seconds before that is referred to, and these are set as the threshold value TH2. compare. Then, for example, when one or more G value VA2 exceeds the threshold value TH2 in the reference range A1, it is considered that the condition of the sudden deceleration event is satisfied.

<Example of vehicle behavior and sudden deceleration judgment operation-2>
Example of the relationship between the acceleration VA1 (km / h / s) detected by the speed pulse signal SG1 and the time-dependent change of the G value VA2 in the vehicle front-rear direction detected by the G sensor 28 and the determination operation in the drive recorder 10- 2 is shown in FIG.

The example shown in FIG. 4 assumes a case where noise is generated in the acceleration VA1 due to wheel slippage or the like even though the vehicle is not actually decelerated suddenly. For example, noise is generated in the acceleration VA1 in the situations shown in FIGS. 7 and 8.

Therefore, in the example shown in FIG. 4, a large change in the acceleration VA1 occurs in the vicinity of the time ta in the negative direction, but since no large change in the behavior of the vehicle actually occurs, the G value VA2 changes over time. No significant change appears in the change within the range of time ta to tb.

In the example shown in FIG. 4, the determination unit 11a of the drive recorder 10 detects that the acceleration VA1 exceeds the determination threshold value TH1 at the time ta, and considers that “the image transmission determination is valid” (step S03). However, since the determination unit 11a detects that the G value VA2 within the range of time ta to tb in FIG. 4 is equal to or less than the threshold value TH2, the image transmission is canceled (step S04).

That is, by monitoring the behavior of both the acceleration VA1 and the G value VA2 by the determination unit 11a, the influence of the noise generated in the acceleration VA1 can be eliminated, and it can be correctly determined whether or not the sudden deceleration event has occurred. Further, when noise caused by wheel slip or the like is not generated in the acceleration VA1, it is determined based on the G value by detecting a sudden deceleration in step S01 of FIG. 2 based on the acceleration VA1. Judgment with higher accuracy is realized.

<Structure example-2 of acceleration table TB1>
FIG. 5 shows a specific example-2 of the configuration of the acceleration table TB1 and the contents to be retained. The content of the acceleration table TB1 shown in FIG. 5 represents the data of the situation corresponding to the change with time of the acceleration VA1 and the G value VA2 shown in FIG.

The determination unit 11a compares the acceleration VA1 in the acceleration storage area TB1c with the determination threshold value TH1 at the timing of time t0 in FIG. 5, and the state of “−VA1> TH1”, that is, the state of time ta in FIG. When it detects that it has become, it processes as follows. That is, with reference to this time t0 (= ta), the G value VA2 of the G value storage area TB1d of the reference range A1 up to the time t-9 0.9 seconds before that is referred to, and these are set as the threshold value TH2. compare.

In the example shown in FIG. 5, in the G value storage area TB1d of the reference range A1 corresponding to the range of time ta to tb of FIG. 4, the determination unit 11a determines that the G value VA2 is equal to or less than the threshold value TH2 in step S05. Since it is recognized by, the transmission of the image is canceled. That is, the determination unit 11a determines that the sudden deceleration event has not occurred.

<Specific processing procedure for sudden deceleration event detection>
FIG. 6 shows an operation example of the drive recorder 10 for determining a sudden deceleration event. That is, the CPU 11 including the determination unit 11a executes the processing procedure shown in FIG. 6 and detects a sudden deceleration of the vehicle. Further, when executing the processing procedure of FIG. 6, the vehicle speed (km / h) specified by the speed pulse signal SG1, the G value of the G sensor output SG2, and the acceleration table TB1 are used.

Further, the current speed Vc shown in FIG. 6 corresponds to the vehicle speed (km / h) specified by the speed pulse signal SG1. The sudden deceleration threshold value Vs shown in FIG. 6 corresponds to the determination threshold value TH1 shown in FIGS. 2 and 4. Further, the current G value Gc shown in FIG. 6 corresponds to the G value of the G sensor output SG2. The image transmission G threshold value Gs shown in FIG. 6 corresponds to the threshold value TH2 shown in FIGS. 2 and 4. The operation of FIG. 6 will be described below.

The CPU 11 starts measuring the state of the vehicle in step S11. That is, thereafter, the latest values of the vehicle speed (km / h) specified by the speed pulse signal SG1 and the G value of the G sensor output SG2 are repeatedly acquired. Then, each of the acquired vehicle speed and G value is reflected in the contents of the speed storage area TB1b and the G value storage area TB1d of the acceleration table TB1. The latest vehicle speed is the current speed Vc. The latest G value is the current G value Gc.

In the present embodiment, it is necessary to refer to the past vehicle G value for the reference range A1 from the time t0 when the alarm is generated to the time t-9 that goes back to a certain time (for example, 1 second) before. Therefore, the contents of the acceleration table TB1 are always updated to the latest contents so that the CPU 11 can always refer to the past vehicle G value of at least the reference range A1 on the acceleration table TB1.

For example, in the G value storage area TB1d of the acceleration table TB1, the CPU 11 processes the history of 10 G values in the range from the alarm occurrence time to the measurement time 10 times before (S12).

That is, the G value Gn-8 is moved to the position of the G value Gn-9, the G value Gn-7 is moved to the position of the G value Gn-8, and the G value Gn-6 is moved to the position of the G value Gn-7. Move, move G value Gn-5 to the position of G value Gn-6, move G value Gn-4 to the position of G value Gn-5, move G value Gn-3 to the position of G value Gn-4. , G value Gn-2 is moved to the position of G value Gn-3, G value Gn-1 is moved to the position of G value Gn-2, and the current G value Gc is moved to the position of G value Gn. Write. Here, G value Gn-9, G value Gn-8, G value Gn-7, G value Gn-6, G value Gn-5, G value Gn-4, G value Gn-3, G value Gn-2. , G value Gn-1, and G value Gn are time t-9, t-8, t-7, t-6, t-5, t-4, t-3, t-2, t-1 respectively. , And the G value of t0.

Further, in order to update the contents of the acceleration table TB1 every 0.1 seconds (100 ms), the CPU 11 waits (waits) for 0.1 seconds in step S13. That is, the update process of S12 is repeated every 0.1 seconds, and the contents of the acceleration table TB1 are updated every 0.1 seconds.

Further, at the timing of measuring the speed, for example, at the time ta in FIG. 2, the CPU 11 proceeds from S14 to S15. In step S15, the CPU 11 acquires the _{nth velocity Vn and the n-1st velocity V n-1} required for calculating the velocity change rate (= acceleration: km / h / s) per second. That is, the n-1st velocity V _n-1 is the nth velocity Vn before the update in the velocity storage area TB1b of the acceleration table TB1. Further, the nth speed Vn is set to the current speed (latest vehicle speed) Vc, and the nth speed Vn on the acceleration table TB1 is updated.

In step S16, the CPU 11 calculates an acceleration (V _{n-1 -Vn) (= VA1) from Vn and V n-1} acquired in S15, and compares this acceleration with the sudden deceleration threshold value Vs. If the acceleration (V _n-1- Vn) is equal to or greater than the sudden deceleration threshold value Vs, the process proceeds to the next S17.

In step S17, the CPU 11 is in the range from the current time (= t0) to 0.9 seconds before, that is, the G values Gn, Gn-1, Gn-2, Gn-3 of the G value storage area TB1d in the reference range A1. , ..., Each of Gn-9 is compared with the image transmission G threshold value Gs. Then, when one or more of the 10 G values Gn to Gn-9 is equal to or greater than the image transmission G threshold value Gs, the process proceeds to the next S18.

In step S18, the CPU 11 transmits the image data of the image obtained by the shooting of the vehicle-mounted camera 23 to the office PC 30 by using the wireless communication of the communication unit 24 for a certain period of time, for example. Of course, data other than images may be transmitted at the same time. If the operation of the vehicle is not completed, the process returns from the next S19 to S12, and the above process is repeatedly executed.

That is, when the CPU 11 executes the process according to the procedure shown in FIG. 6, it is possible to detect an event of sudden deceleration behavior in the vehicle in the situations shown in FIGS. 2 and 3, and this event is detected. Occasionally, image data can be automatically sent to the office PC 30 in S18.

On the other hand, in the situations shown in FIGS. 4 and 5, the determination condition of S16 of FIG. 6 is satisfied, but the determination condition of S17 is not satisfied, so that the execution of S18 is canceled and the image is displayed from the drive recorder 10. It will not be sent.

<Advantages of drive recorder 10>
The drive recorder 10 shown in FIG. 1 has a speed change rate calculated from a speed signal and a large amount of acceleration applied to the vehicle when determining the presence or absence of behavior indicating sudden deceleration of the vehicle due to a driver's braking operation or the like. The judgment condition that is combined with the G value representing the value is used. That is, by determining the presence or absence of behavior using the speed change rate calculated from the speed signal, the determination accuracy is improved as compared with the case of determining using the G value. However, in a special environment where the wheels slip, a large error occurs between the speed signal and the actual speed of the vehicle body. Therefore, when judging only by the speed change rate, for example, FIGS. 7 and 8 are shown. Misjudgment occurs in such a situation. However, erroneous determination can be prevented by using the determination condition that combines the speed change rate and the G value.

In the above-described embodiment, it is assumed that the present invention is applied to the drive recorder 10, but the present invention may be applied to other in-vehicle devices. Further, the algorithm for determining sudden deceleration as shown in FIG. 6 can be applied to operations other than the on-board unit such as the drive recorder 10. For example, when the office PC 30 reads the operation data recorded on the memory card 65 and processes the data, the sudden deceleration event during the vehicle operation can be determined with high accuracy by executing the same processing as in FIG. .. Alternatively, when a server (not shown) arranged on the network 70 receives data from the drive recorder 10 and processes the data, the same process as in FIG. 6 is executed, so that the user such as the office PC 30 can use it. On the other hand, it is possible to provide a service for detecting sudden deceleration events.

Here, the features of the on-board unit and the sudden deceleration event detection method according to the above-described embodiment of the present invention are briefly summarized and listed below in [1] to [5], respectively.
[1] A speed signal acquisition unit (speed I / F12A) that acquires a speed signal (speed pulse signal SG1) indicating the speed of the vehicle, and
A G value acquisition unit (sensor input I / F14) that acquires a G value (G sensor output SG2) indicating the magnitude of acceleration applied to the vehicle, and
An event detection unit (determination) that detects an event related to sudden deceleration of the vehicle based on a determination condition that combines the speed change rate (V _{n-1-Vn) calculated from the speed signal and the G value.} Part 11a, S15 to S17) and
An event processing unit (CPU11, S18) that executes a predetermined process when the event is detected, and
An in-vehicle device (drive recorder 10) characterized by being equipped with.

[2] A photographing device for photographing at least one of the inside and the outside of the vehicle is provided.
As the predetermined process, the event processing unit transmits an image captured by the photographing device to a predetermined external device in the vicinity of the time when the event occurs.
The on-board unit according to the above [1].

[3] The G value acquisition unit has a G value history holding unit (acceleration table TB1) capable of holding a plurality of the G values detected at different timings.
The event detection unit detects an event related to the sudden deceleration of the vehicle based on the speed change rate and the plurality of G values held in the G value history holding unit.
The vehicle-mounted device according to the above [1] or [2].

[4] In the event detection unit, the speed change rate exceeds a predetermined threshold value (S16), and a plurality of the G values held in the G value history holding unit satisfy a predetermined condition (S17). In the case of detecting an event related to the sudden deceleration of the vehicle,
The on-board unit according to the above [3].

[5] Acquire information on a speed signal (speed pulse signal SG1) indicating the speed of the vehicle, and obtain the information.
The information of the G value (G sensor output SG2) indicating the magnitude of the acceleration applied to the vehicle is acquired, and the information is obtained.
It is related to the sudden deceleration of the vehicle based on the determination condition (S15 to S17) that combines the _{speed change rate (V n-1-} Vn) calculated from the speed signal information and the G value information. Detects an event
Output the event information (S18),
A sudden deceleration event detection method characterized by this.

5 Operation management system 8 Wireless base station 10 Drive recorder 11, 31 CPU
11a Judgment unit 12A Speed I / F
12B engine rotation I / F
13 External input I / F
14 Sensor input I / F
15 GPS receiver 15a GPS antenna 16 camera I / F
17 Recording unit 18 Card I / F
19 Voice I / F
20, 42 speakers 21 RTC
22 SW input unit 23 In-vehicle camera 24, 32 Communication unit 25 Power supply unit 26A Non-volatile memory 26B Volatile memory 27 Display unit 28 G sensor 29 Analog input I / F
30 office PC
33 Display unit 34 Storage unit 35 Card I / F
36 Operation unit 37 Output unit 38 Voice I / F
41 Microphone 48 External I / F
51 Vehicle speed sensor 54 External storage device 55 Accident point DB
56 Operation data DB
57 Hazard map DB
65 Memory card 70 Network TB1 Acceleration table TB1a Time management area TB1b Speed storage area TB1c Acceleration storage area TB1d G value storage area A1 Reference range SG1 Speed pulse signal SG2 G sensor output

Claims (2)

A speed signal acquisition unit that acquires a speed signal generated in conjunction with the rotation of the wheels of the vehicle from the vehicle speed sensor that detects the rotation of the wheels.
A G value acquisition unit that acquires a G value indicating the magnitude of acceleration applied to the vehicle from an acceleration sensor mounted on the vehicle, and a G value acquisition unit.
An event detection unit that detects an event related to sudden deceleration of the vehicle based on a determination condition that combines the speed change rate calculated from the speed signal and the G value.
An imaging device that captures at least one of the inside and outside of the vehicle,
When the event is detected, an event processing unit that transmits an image captured by the photographing device to a predetermined external device in the vicinity of the time when the event occurs , and an event processing unit.
Equipped with a,
The G value acquisition unit has a G value history holding unit capable of holding a plurality of the G values detected at different timings.
The event detection unit has a plurality of G values held in the G value history holding unit in a range from the current time before a predetermined time to the present when the current rate of change in speed exceeds a predetermined threshold value. An event related to a sudden deceleration of the vehicle is detected based on the fact that one or more of the G values exceeds a predetermined second threshold value.
An in-vehicle device characterized by that. For on-board equipment mounted on the vehicle
The speed signal generated in synchronization with the rotation of the wheels of the vehicle is acquired from a vehicle speed sensor for detecting the rotation of the wheel,
The G value representing the magnitude of the acceleration applied to the vehicle is acquired from the acceleration sensor mounted on the vehicle,
A speed change ratio calculated the velocity signal or al, based on the determination condition combining with the G values, to detect events related to the rapid deceleration of the vehicle,
When the event is detected, sudden deceleration event detection causes a predetermined external device to transmit an image captured by a photographing device that images at least one of the inside and the outside of the vehicle in the vicinity of the time when the event occurs. It ’s a method,
In the in-vehicle device
A plurality of the G values detected at different timings are held in the G value history holding unit.
One or more of the plurality of G values held in the G value history holding unit in the range from the current time before the predetermined time to the present when the current rate of change in speed exceeds a predetermined threshold value. Based on the fact that the G value exceeds a predetermined second threshold value, an event related to the sudden deceleration of the vehicle is detected.
A sudden deceleration event detection method characterized by this.

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