Travel data recording device, travel data recording method, and travel data recording-purpose computer program

Abstract

To provide a travel data recording device that can record comparatively long-term travel data of a vehicle, including timing of an event while the vehicle is traveling.SOLUTION: A travel data recording device includes: a storage processing unit 21 that stores travel data on a vehicle 1 in a volatile memory 12; a first duplication processing unit 22 that duplicates and stores travel data for a first time period stored in the volatile memory 12 in either a first non-volatile memory 13 or a second non-volatile memory 14 every time a first time period elapses; and a second duplication processing unit 24 that duplicates and stores travel data for a second time period which includes timing at which occurrence of an event is detected and is longer than the first time period of the travel data stored in one non-volatile memory, from one non-volatile memory to the other non-volatile memory when reaching a save timing after lapse of a predetermined time elapses after the detection of the occurrence of a predetermined event.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a driving data recording device, a driving data recording method, and a driving data recording computer program for recording data obtained while a vehicle is driving. [Background technology]

[0002] A technology for recording vehicle data while the vehicle is running has been proposed (see Patent Document 1).

[0003] In the technology disclosed in Patent Document 1, an information processing device stores first vehicle data for T1 seconds in volatile memory while overwriting old data until a predetermined vehicle condition is detected, and stores second vehicle data for T2 seconds in volatile memory upon detecting the vehicle condition. The information processing device then records the first vehicle data from volatile memory to nonvolatile memory upon detecting the vehicle condition, and records the second vehicle data from volatile memory to nonvolatile memory as needed before all of the second vehicle data has been stored in volatile memory for T2 seconds. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-73610 Summary of the Invention [Problem to be solved by the invention]

[0005] To analyze the details of an event that occurred while the vehicle was running, vehicle data just before and after the event may not be sufficient.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a driving data recording device that can record driving data of a vehicle for a relatively long period of time, including the timing at which an event occurs while the vehicle is driving. [Means for solving the problem]

[0007] According to one embodiment, a travel data recording device is provided, which includes a volatile memory, a first nonvolatile memory, a second nonvolatile memory, a storage processor that stores travel data representing conditions of the vehicle or its surroundings while the vehicle is traveling in the volatile memory, a first duplication processor that copies and stores the travel data for the first period stored in the volatile memory into one of the first nonvolatile memory and the second nonvolatile memory each time a first period elapses, and a second duplication processor that copies and stores, from the one nonvolatile memory, travel data for a second period that includes the time when the occurrence of a predetermined event is detected and is longer than the first period, into the other of the first nonvolatile memory and the second nonvolatile memory at a save timing that is a predetermined time after the occurrence of a predetermined event is detected.

[0008] In one embodiment, the driving data recording device further has a transmission processing unit that determines whether the amount of data for the driving data for the second period is below a predetermined transmission upper threshold, and if the data amount is below the transmission upper threshold, transmits the driving data for the second period stored in the other non-volatile memory to another device via a communication terminal installed in the vehicle at a transmission timing after the evacuation timing, while if the data amount exceeds the transmission upper threshold, transmits a collection request signal requesting collection of the driving data for the second period to the other device via the communication terminal.

[0009] In one embodiment, the driving data recording device further has a switching processing unit that swaps one nonvolatile memory with the other nonvolatile memory each time a switching period longer than the second period has elapsed, or each time the number of times the driving data for the first period has been stored in one nonvolatile memory reaches a predetermined number of switching times.

[0010] In one embodiment, the traveling data recording device further includes a detection unit that detects the occurrence of a predetermined event and identifies the type of the event that has occurred, and the second replication processing unit determines the length of the second period according to the identified type of event.

[0011] In one embodiment, the traveling data recording device further includes a detection unit that detects the occurrence of a predetermined event and identifies the type of the event that occurred, and a second replication processing unit that determines the type of data item to be included in the traveling data that is replicated and stored from one nonvolatile memory to the other nonvolatile memory according to the identified type of event.

[0012] According to another aspect, there is provided a driving data recording method including: storing driving data representing a state of the vehicle or an area surrounding the vehicle while the vehicle is traveling in a volatile memory; duplicating and storing the driving data for the first period stored in the volatile memory in one of a first non-volatile memory and a second non-volatile memory each time a first period elapses; and, at a save timing that is a predetermined time after a timing at which the occurrence of a predetermined event is detected, copying and storing, from the one non-volatile memory, driving data for a second period that includes the timing at which the occurrence of the event is detected and is longer than the first period, from the one non-volatile memory to the other of the first non-volatile memory and the second non-volatile memory.

[0013] According to yet another aspect, there is provided a computer program for recording driving data, the computer program including instructions for causing a processor mounted on a vehicle to execute the following steps: store driving data representing a state of the vehicle or a state around the vehicle while the vehicle is traveling in a volatile memory; copy and store the driving data for the first period stored in the volatile memory into one of a first nonvolatile memory and a second nonvolatile memory each time a first period elapses; and copy and store, from the one nonvolatile memory, driving data for a second period that includes the detection of the occurrence of a predetermined event and is longer than the first period, from the one nonvolatile memory to the other of the first nonvolatile memory and the second nonvolatile memory, at a save timing that is a predetermined time after the detection of the occurrence of a predetermined event. [Effects of the Invention]

[0014] The traveling data recording device according to the present disclosure has the advantage of being able to record traveling data of a vehicle for a relatively long period of time, including the timing at which an event occurs while the vehicle is traveling. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a schematic diagram of a vehicle equipped with a driving data recording device; [Figure 2] FIG. 2 is a hardware configuration diagram of the driving data recording device. [Figure 3] FIG. 2 is a functional block diagram of a processor of the driving data recording device. [Figure 4] FIG. 2 is a diagram illustrating an outline of a driving data recording process. [Figure 5] 10 is an operational flowchart of a travel data recording process. DETAILED DESCRIPTION OF THE INVENTION

[0016] A travel data recording device, a travel data recording method executed by the travel data recording device, and a travel data recording computer program executed by the travel data recording device will be described below with reference to the accompanying drawings. The travel data recording device is installed in a vehicle and sequentially stores travel data representing the vehicle or its surrounding conditions while the vehicle is traveling in a volatile memory. Each time a first period elapses, the travel data recording device saves a copy of the travel data for the first period stored in the volatile memory to one of two nonvolatile memories (hereinafter, saving a copy of travel data stored in one memory to the other memory is simply referred to as "storing a copy of travel data" or "storing a copy of travel data"). Furthermore, when a predetermined time has elapsed since the detection of a predetermined event, the travel data recording device copies and saves travel data for a second period that includes the detection of the event and is longer than the first period from one nonvolatile memory to the other nonvolatile memory. This allows the travel data recording device to record travel data for a relatively long period, including the time when an event occurred while the vehicle was traveling.

[0017] 1 is a schematic diagram of a vehicle equipped with a traveling data recording device. The vehicle 1 has at least one behavior sensor 2, a camera 3, a wireless communication terminal 4, a traveling data recording device 5, and an electronic control unit (ECU) 6 that controls each part of the vehicle 1. The behavior sensor 2, the camera 3, the wireless communication terminal 4, and the ECU 6 are communicatively connected to the traveling data recording device 5. The vehicle 1 may also be provided with a ranging sensor (not shown) such as a LiDAR or radar that measures the distance to objects around the vehicle 1. The vehicle 1 may also be provided with a device (not shown) such as a GPS receiver that determines the position of the vehicle 1 using a satellite positioning system.

[0018] At least one behavior sensor 2 is a sensor that measures the behavior of the vehicle 1. The behavior sensor 2 includes, for example, at least one of a speed sensor, an acceleration sensor, and an angular velocity sensor. Each behavior sensor 2 generates a sensor signal that represents the behavior of the vehicle 1 and outputs the sensor signal to the ECU 6. Each behavior sensor 2 may also output the generated sensor signal to the traveling data recording device 5.

[0019] The camera 3 captures an image of a predetermined area around the vehicle 1 or inside the cabin of the vehicle 1, generates an image showing the predetermined area at predetermined intervals, and outputs the generated image to the traveling data recording device 5 and the ECU 6. The predetermined area is, for example, an area in front of or behind the vehicle 1, or an area inside the cabin of the vehicle 1 that includes the position of the driver of the vehicle 1. The vehicle 1 may be provided with multiple cameras 3 with different shooting directions or focal lengths. Hereinafter, an image showing the predetermined area around the vehicle 1 will be referred to as an outside-vehicle image. An image showing the driver will be referred to as a driver image.

[0020] The wireless communication terminal 4 is an example of a communication device, and is a device that executes wireless communication processing in accordance with a predetermined wireless communication standard. For example, by accessing a wireless base station (not shown), it is connected to a server (not shown) that collects driving data via the wireless base station and a communication network. That is, a communication line is established between the wireless communication terminal 4 and the server via the wireless base station and the communication network. The wireless communication terminal 4 then generates an uplink wireless signal containing the driving data to be collected, received from the driving data recording device 5, and transmits the uplink wireless signal to the wireless base station, thereby transmitting the driving data to the server.

[0021] The ECU 6 controls each part of the vehicle 1. Specifically, the ECU 6 assists the driver of the vehicle 1 in driving by using the sensor signals from the behavior sensor 2. Alternatively, the ECU 6 may control the vehicle 1 for automatic driving by using the sensor signals from the behavior sensor 2. Furthermore, the ECU 6 outputs a status signal indicating the status of the vehicle 1 to the running data recording device 5. At that time, if the ECU 6 detects an abnormality in any of the parts of the vehicle 1 to be controlled or in the ECU 6 itself, the ECU 6 includes information indicating the detected abnormality in the status signal.

[0022] 2 is a hardware configuration diagram of the running data recording device 5. The running data recording device 5 has a communication interface 11, a volatile memory 12, a first non-volatile memory 13, a second non-volatile memory 14, and a processor 15. Furthermore, the running data recording device 5 may be provided with an external interface (not shown) for connecting peripheral devices that conforms to a predetermined interface standard, such as USB (registered trademark).

[0023] The communication interface 11 is an example of an in-vehicle communication unit and includes an interface circuit for communicatively connecting the traveling data recording device 5 to each of the behavior sensors 2, the camera 3, the wireless communication terminal 4, and the ECU 6. Each time the communication interface 11 receives a sensor signal from each of the behavior sensors 2, the communication interface 11 passes the received sensor signal to the processor 15. The communication interface 11 may also receive the sensor signal from each of the behavior sensors 2 via the ECU 6. Each time the communication interface 11 receives an image from the camera 3, the communication interface 11 passes the received image to the processor 15. Furthermore, each time the communication interface 11 receives information from the server via the wireless communication terminal 4, the communication interface 11 passes the information to the processor 15. Furthermore, when the communication interface 11 receives a status signal indicating the status of the vehicle 1 from the ECU 6, the communication interface 11 passes the status signal to the processor 15. Furthermore, the communication interface 11 outputs the traveling data received from the processor 15 to the wireless communication terminal 4.

[0024] The volatile memory 12 is configured as an integrated circuit of a volatile semiconductor memory such as a DRAM or an SRAM. In this embodiment, the volatile memory 12 is configured as a ring buffer, and the processor 15 sequentially writes the driving data to the volatile memory 12. The volatile memory 12 has a storage area large enough to store the amount of data obtained by multiplying the amount of data corresponding to the driving data obtained in a period having a first length (hereinafter simply referred to as the first period) by a predetermined margin coefficient (1 or more, for example, 1.1 to 1.3). The first period is a unit period during which the driving data stored in the volatile memory 12 is copied to either the first non-volatile memory 13 or the second non-volatile memory 14, and is set to a length of, for example, several minutes to several tens of minutes. When the storage area of the volatile memory 12 becomes full, the oldest driving data is overwritten.

[0025] The first nonvolatile memory 13 and the second nonvolatile memory 14 are each configured as an integrated circuit of a nonvolatile semiconductor memory. The first nonvolatile memory 13 and the second nonvolatile memory 14 may be configured as separate integrated circuits, or may be configured as different storage areas in a single integrated circuit.

[0026] One of the first nonvolatile memory 13 and the second nonvolatile memory 14 stores a copy of the driving data stored in the volatile memory 12 in units of a first period. Furthermore, after a predetermined event is detected, the other of the first nonvolatile memory 13 and the second nonvolatile memory 14 stores a copy of the driving data for a second length of time (hereinafter simply referred to as the second period) stored in one of the first nonvolatile memory 13 and the second nonvolatile memory 14. Therefore, each of the first nonvolatile memory 13 and the second nonvolatile memory 14 has a storage area of a size capable of storing the amount of data obtained by multiplying the amount of data corresponding to the driving data obtained in the second period by a predetermined margin coefficient (1 or more, for example, 1.1 to 1.3).

[0027] The processor 15 includes one or more central processing units (CPUs) and their peripheral circuits. The processor 15 may further include other arithmetic circuits such as a logic operation unit, a numerical operation unit, or a graphics processing unit. The processor 15 executes a driving data recording process while the vehicle 1 is driving.

[0028] 3 is a functional block diagram of the processor 15 related to the driving data recording process. The processor 15 has a storage processing unit 21, a first duplication processing unit 22, a detection unit 23, a second duplication processing unit 24, a transmission processing unit 25, and a switching processing unit 26. Each of these units in the processor 15 is a functional module realized by, for example, a computer program running on the processor 15. Alternatively, each of these units in the processor 15 may be a dedicated arithmetic circuit provided in the processor 15.

[0029] The storage processing unit 21 sequentially stores the travel data in the volatile memory 12. As described above, the travel data is data representing the situation of the vehicle 1 or the surroundings of the vehicle 1 while the vehicle 1 is traveling. The travel data includes, for example, at least one of a value representing the behavior of the vehicle 1 represented by a sensor signal from the behavior sensor 2, an outside image or a driver image obtained by the camera 3, a value related to the driving operation or control of the vehicle 1 obtained from the ECU 6, and data representing the operating state of the ECU 6. The value representing the behavior of the vehicle 1 includes, for example, at least one of the speed, acceleration, and angular velocity of the vehicle 1. The value related to the driving operation or control of the vehicle 1 includes, for example, at least one of the steering angle, accelerator opening, brake pedal depression amount, remaining battery charge, headlight mode, and wiper operation mode. Furthermore, if a distance measurement sensor is provided in the vehicle 1, the distance to an object around the vehicle 1 represented by a distance measurement signal generated by the distance measurement sensor may also be included in the travel data. Furthermore, if the vehicle 1 is provided with a positioning device such as a GPS receiver, the position of the vehicle 1 measured by that device may also be included in the travel data.

[0030] The storage processing unit 21 generates traveling data by including a set of data contained in the traveling data in one piece of traveling data each time the set of data is received from the behavior sensor 2, the camera 3, and the ECU 6. At this time, the storage processing unit 21 generates traveling data by including the set of data in the traveling data according to a predetermined traveling data format. The storage processing unit 21 may also compress the set of data according to a predetermined compression format before including it in the traveling data. A single piece of traveling data includes a set of data whose reception timing difference at the traveling data recording device 5 is within a predetermined allowable time (e.g., 100 msec to 1 sec). The storage processing unit 21 may also include time information in the traveling data indicating the time when the traveling data was generated. Each time the storage processing unit 21 generates traveling data, it stores the generated traveling data in the free space of the volatile memory 12. However, if the free space of the volatile memory 12 is insufficient to store the traveling data, the storage processing unit 21 overwrites the oldest traveling data stored in the volatile memory 12 with the newest traveling data.

[0031] Each time the first period elapses, the first replication processing unit 22 replicates and stores the latest driving data for the first period stored in the volatile memory 12 in either the first non-volatile memory 13 or the second non-volatile memory 14. The first replication processing unit 22 may erase the original driving data stored in the volatile memory 12 or may leave it as is. Hereinafter, the non-volatile memory in which the driving data is replicated and stored from the volatile memory 12, either the first non-volatile memory 13 or the second non-volatile memory 14, may be referred to as the primary replication memory. A flag indicating whether the primary replication memory or the other non-volatile memory is stored in a storage area of the first non-volatile memory 13 or the second non-volatile memory 14 other than the storage area for the driving data. The first replication processing unit 22 can identify which of the first non-volatile memory 13 and the second non-volatile memory 14 is the primary replication memory by referencing the flag.

[0032] In the primary copy memory, the driving data is written sequentially in units of the first period after the ignition switch of the vehicle 1 is turned on. Therefore, all driving data after the ignition switch is turned on is saved until the storage area of the primary copy memory becomes full. When the storage area of the primary copy memory becomes full, the first copy processing unit 22 overwrites the oldest driving data for the first period with the latest driving data for the first period among the driving data saved in the primary copy memory.

[0033] Each time the first copy processing unit 22 completes copying and storing the travel data for the first period in the primary copy memory, it notifies the switching processing unit 26 of this fact.

[0034] The detection unit 23 detects that a predetermined event has occurred in the vehicle 1 or around the vehicle 1. The predetermined event is an event that requires collection of driving data before and after the occurrence of the event, and may be, for example, an accident, an emergency avoidance of the vehicle 1 in response to some kind of danger, or an abnormal occurrence by the driver of the vehicle 1.

[0035] Therefore, the detection unit 23 determines whether a value representing the behavior of the vehicle 1 represented by a sensor signal from the behavior sensor 2, a value related to the driving operation or control of the vehicle 1 from the ECU 6, or data representing the operating state of the ECU 6 satisfies a predetermined event detection condition. If the predetermined event detection condition is satisfied, the detection unit 23 determines that a predetermined event has occurred and detects the occurrence of the event. On the other hand, if the predetermined event detection condition is not satisfied, the detection unit 23 does not detect the occurrence of the predetermined event.

[0036] The event detection condition may be, for example, that the absolute value of the acceleration of the vehicle 1 or the absolute value of the angular velocity of the vehicle 1, which is represented by a sensor signal from the behavior sensor 2, exceeds a predetermined threshold. Alternatively, the event detection condition may be that the amount of fluctuation in the steering angle received from the ECU 6 within a predetermined sampling interval (for example, 100 msec to 1 sec) exceeds a predetermined threshold. Alternatively, the event detection condition may be that the data representing the operating state of the ECU 6 includes a value representing some kind of failure.

[0037] The detection unit 23 may also determine whether an event detection condition is satisfied based on an exterior image of the vehicle or an image of the driver captured by the camera 3. In this case, the detection unit 23 inputs the exterior image of the vehicle or the image of the driver to a classifier that has been trained in advance to determine whether a predetermined event has occurred. If the classifier outputs a classification result indicating that a predetermined event has occurred, the detection unit 23 determines that the event detection condition is satisfied. The classifier is configured as a convolutional neural network (CNN)-type deep neural network (DNN) having, from the input side, one or more convolutional layers and one or more fully connected layers. Alternatively, the classifier may be configured based on a machine learning method other than a neural network, such as a support vector machine or AdaBoost. Such a classifier is trained in advance according to a predetermined supervised learning method, such as backpropagation, using a large number of training images including images depicting a situation corresponding to a predetermined event, for example, an accident or an abnormal situation.

[0038] When the detection unit 23 detects the occurrence of a predetermined event, it notifies the second replication processing unit 24 of the occurrence.

[0039] When the evacuation timing arrives after a predetermined time (for example, several tens of seconds to several minutes) has elapsed since the occurrence of a predetermined event was detected, the second copy processing unit 24 copies and stores the driving data for a second period from the driving data stored in the primary copy memory into the other of the first non-volatile memory 13 and the second non-volatile memory 14. Hereinafter, the other of the first non-volatile memory 13 and the second non-volatile memory 14 may be referred to as the secondary copy memory.

[0040] The second period includes the timing at which the occurrence of the event is detected and is longer than the first period, and can be, for example, several tens of minutes to one hour or more. Therefore, if the timing at which the ignition switch is turned on is earlier than the timing that precedes the save timing by the upper limit value of the length of the second period (hereinafter referred to as the upper limit length start timing), the second copy processing unit 24 may set the upper limit length start timing as the start timing of the second period. On the other hand, if the upper limit length start timing is earlier than the timing at which the ignition switch is turned on, the second copy processing unit 24 may set the timing at which the ignition switch is turned on as the start timing of the second period. In the above example, the save timing is set as the end of the second period, but the end of the second period may be earlier than the save timing as long as it is later than the timing at which the occurrence of the event is detected.

[0041] When the second replication processing unit 24 has completed replicating and storing the travel data for the second period in the secondary replication memory, it notifies the transmission processing unit 25 of this fact. Furthermore, when the replicating and storing in the secondary replication memory is completed, the second replication processing unit 24 may either delete the original travel data stored in the primary replication memory, or leave it as is. Furthermore, when the ignition switch of the vehicle 1 is turned off without detecting a predetermined event, the second replication processing unit 24 may delete the travel data stored in the primary replication memory.

[0042] When the transmission processing unit 25 is notified that the copying and storage of the traveling data for the second period in the secondary duplicate memory has been completed, the transmission processing unit 25 transmits the traveling data for the second period stored in the secondary duplicate memory at a subsequent predetermined transmission timing to the server via the communication interface 11 and the wireless communication terminal 4. The server is an example of another device.

[0043] The predetermined transmission timing may be, for example, the timing immediately after notification that the copying and storing of the traveling data for the second period in the secondary copy memory has been completed, or any timing from the timing immediately after the notification until the ignition switch of the vehicle 1 is turned off. Alternatively, the predetermined transmission timing may be the timing when the ignition switch is turned on again after the ignition switch has been turned off.

[0044] According to a modified example, the transmission processing unit 25 may determine whether the amount of travel data for the second period stored in the secondary replica memory is equal to or less than a predetermined transmission upper threshold. The transmission upper threshold is set as a value corresponding to the amount of data that can be communicated by the wireless communication terminal 4 in a predetermined time (e.g., several minutes). If the amount of data is equal to or less than the transmission upper threshold, the transmission processing unit 25 transmits the travel data for the second period stored in the secondary replica memory to the server via the communication interface 11 and the wireless communication terminal 4 at the transmission timing. On the other hand, if the amount of travel data for the second period exceeds the transmission upper threshold, the transmission processing unit 25 transmits a collection request signal requesting collection of the travel data for the second period to the server via the communication interface 11 and the wireless communication terminal 4 at the transmission timing. Note that the transmission processing unit 25 includes identification information of the vehicle 1 and information indicating the amount of travel data for the second period in the collection request signal. In this case, the travel data stored in the secondary replica memory may be output to a peripheral device (not shown) connected via an external interface. In addition, the transmission processing unit 25 may display a message on a display device (not shown) provided in the driving data recording device 5 or a display device (not shown) provided in the passenger compartment of the vehicle 1, instructing the driver to head to a facility that can accommodate data collection.

[0045] According to this modified example, the transmission processing unit 25 can appropriately determine whether to transmit the driving data via wireless communication or have it collected individually, depending on the amount of driving data stored in the secondary replication memory.

[0046] The transmission processing unit 25 erases the traveling data from the secondary replica memory after transmitting the traveling data via the wireless communication terminal 4 or after outputting the traveling data to a peripheral device. Furthermore, if the traveling data stored in the secondary replica memory is not collected even after a certain period of time (for example, several days to several weeks) has passed since the collection request signal was transmitted to the server, the transmission processing unit 25 may erase the traveling data from the secondary replica memory.

[0047] If the amount of travel data for the second period exceeds the transmission upper limit threshold, the transmission processing unit 25 may transmit travel data for a third period, which is shorter than the second period, along with a collection request signal to the server via the communication interface 11 and the wireless communication terminal 4. In this case, the third period includes the timing of the event occurrence and may be a period of approximately several tens of seconds to several minutes. If the server determines that the travel data for the entire second period is necessary, the travel data for the second period may be collected via an external interface. On the other hand, if the server determines that the travel data for the entire second period is unnecessary, the server may transmit a discard instruction to the vehicle 1. If the transmission processing unit 25 receives the discard instruction via the wireless communication terminal 4 and the communication interface 11, the transmission processing unit 25 may erase all travel data stored in the secondary replica memory.

[0048] The switching processing unit 26 swaps the primary copy memory with the secondary copy memory each time a predetermined switching period elapses or each time the number of times the traveling data has been copied and stored in the primary copy memory during the first period reaches a predetermined number of switching times. The predetermined switching period can be longer than the second period, for example, several to several tens of times longer than the second period. Each time the switching processing unit 26 swaps the primary copy memory with the secondary copy memory, it stores the date and time of the swap in a storage area other than the traveling data storage area in the first non-volatile memory 13 or the second non-volatile memory 14. The switching processing unit 26 then compares the elapsed time since the previous swap with the switching period, and if the elapsed time reaches the switching period, it swaps the primary copy memory with the secondary copy memory. Alternatively, each time the switching processing unit 26 receives a notification from the first copy processing unit 22 that the traveling data for the first period has been copied and stored, it increments the number of times the copying and storing has occurred by one and compares the number of times the copying and storing has occurred with the predetermined number of switching times. If the number of times the copies have been stored reaches a predetermined number of switching operations, the switching processing unit 26 may switch the primary copy memory with the secondary copy memory. The predetermined number of switching operations may be several to several tens of times the number of switching operations in the first period included in the second period. When the switching processing unit 26 determines to switch the primary copy memory with the secondary copy memory, the switching processing unit 26 switches the primary copy memory with the secondary copy memory when the ignition switch of the vehicle 1 is subsequently turned off. However, if traveling data is stored in the secondary copy memory, the switching processing unit 26 may switch the primary copy memory with the secondary copy memory after the traveling data is erased from the secondary copy memory. After switching the primary copy memory with the secondary copy memory, the switching processing unit 26 rewrites the values of flags indicating the primary copy memory and the secondary copy memory, which are stored in a storage area other than the storage area for traveling data in the first non-volatile memory 13 or the second non-volatile memory 14, to the values after the switching.

[0049] In this way, by switching between the primary and secondary replica memories at regular intervals, the usage of the two nonvolatile memories is leveled out, and therefore the running data recording device 5 can prevent the occurrence of failures in the two nonvolatile memories.

[0050] 4 is a diagram for explaining an outline of the driving data recording process, in which the vertical axis represents elapsed time.

[0051] After the ignition switch of the vehicle 1 is turned on, the traveling data is sequentially stored in the volatile memory 12. Then, as shown in the operating state S1, when the first period T has elapsed, the traveling data for the first period T stored in the volatile memory 12 is copied and stored in the primary replica memory. The copying and storing of the traveling data in the primary replica memory is repeated every time the first period T has elapsed. This copying and storing is performed regardless of whether a predetermined event has occurred. Therefore, as shown in the operating state S2, the copying and storing of the traveling data from the volatile memory 12 to the primary replica memory is performed even after the occurrence of a predetermined event has been detected.

[0052] When the save timing arrives after the occurrence of a predetermined event, the driving data for a second period ending at the save timing is copied from the primary copy memory to the secondary copy memory as shown in operation state S3. As described above, the end of the second period may be before the save timing as long as it is after the occurrence timing of the event.

[0053] Thereafter, as shown in operation state S4, when the ignition switch of the vehicle 1 is turned off, the traveling data for the second period stored in the secondary replica memory is transmitted to the server, and the traveling data in the primary replica memory and the secondary replica memory is erased.

[0054] 5 is an operational flowchart of the running data recording process. The processor 15 executes the running data recording process in accordance with the following operational flowchart.

[0055] The storage processing unit 21 sequentially stores the travel data in the volatile memory 12 (step S101). Furthermore, every time the first period elapses, the first duplication processing unit 22 copies and stores the latest travel data for the first period stored in the volatile memory 12 in the primary duplication memory of the first non-volatile memory 13 or the second non-volatile memory 14 (step S102).

[0056] The detection unit 23 determines whether or not the occurrence of a predetermined event has been detected in the vehicle 1 or around the vehicle 1 (step S103).

[0057] If the occurrence of a predetermined event is not detected (step S103-No), the processor 15 repeats the processes from step S101 onwards. On the other hand, if the occurrence of a predetermined event is detected (step S103-Yes), the second copy processing unit 24 copies and stores the traveling data for the second period stored in the primary copy memory into the secondary copy memory of the first non-volatile memory 13 and the second non-volatile memory 14 at the save timing (step S104).

[0058] The transmission processing unit 25 determines whether the amount of data of the traveling data for the second period stored in the secondary replica memory is equal to or less than a predetermined transmission upper threshold ThU (step S105). If the amount of data is equal to or less than the transmission upper threshold ThU (step S105—Yes), the transmission processing unit 25 transmits the traveling data for the second period stored in the secondary replica memory to the server via the communication interface 11 and the wireless communication terminal 4 (step S106). On the other hand, if the amount of data exceeds the transmission upper threshold ThU (step S105—No), the transmission processing unit 25 transmits a collection request signal to the server via the communication interface 11 and the wireless communication terminal 4 (step S107).

[0059] After step S106 or S107, the switching processing unit 26 determines whether the elapsed time since the previous switching of the primary copy memory and the secondary copy memory has reached the switching period (step S108). If the elapsed time has reached the switching period (step S108—Yes), the switching processing unit 26 switches the primary copy memory and the secondary copy memory (step S109). After step S109, or if the elapsed time has not reached the switching period (step S108—No), the processor 15 ends the running data recording process.

[0060] In step S108, as described above, the switching processing unit 26 may determine whether the number of copies of the traveling data for the first period stored in the primary copy memory has reached the switching count. If the number of copies has reached the switching count, the switching processing unit 26 may execute the process of step S109.

[0061] As described above, this traveling data recording device copies and stores the traveling data for the first period stored in the volatile memory into one of two nonvolatile memories each time a first period elapses. Furthermore, when the save timing arrives, which is a predetermined time after the timing at which a predetermined event is detected, this traveling data recording device copies and stores the traveling data for a second period that includes the timing at which the event is detected and is longer than the first period, from one nonvolatile memory to the other nonvolatile memory. This allows this traveling data recording device to record traveling data for a relatively long period, including the timing at which an event occurs while the vehicle is traveling.

[0062] According to a modified example, the length of the second period may be changed depending on the type of event that has occurred. In this case, the event detection condition is set in advance for each type of event. For example, if the type of event is an accident, the event detection condition may be that the absolute value of the acceleration or the absolute value of the angular velocity is equal to or greater than a predetermined threshold. On the other hand, if the type of event is a driver abnormality, the event detection condition may be that the driver abnormality is detected from the driver image. Then, the detection unit 23 determines whether the event occurrence condition corresponding to each type of event is satisfied. If any of the event occurrence conditions is satisfied, the detection unit 23 identifies the type of the event that has occurred as corresponding to the satisfied event occurrence condition. Then, the detection unit 23 notifies the second duplication processing unit 24 not only that the occurrence of the event has been detected but also the identified type of event.

[0063] The second copy processing unit 24 determines the upper limit of the length of the second period corresponding to the type of event identified by the detection unit 23 by referring to a table showing the relationship between the type of event and the upper limit of the length of the second period. For example, the second period is set longer when the type of event is a driver abnormality than when the type of event is an accident. Such a table may be stored in advance in a storage area other than the storage area for the driving data in the first non-volatile memory 13 or the second non-volatile memory 14. The second copy processing unit 24 then performs processing similar to that of the above embodiment in accordance with the determined upper limit of the second period, thereby copying and storing the driving data for the second period from the primary copy memory to the secondary copy memory. According to this modification, the driving data recording device 5 can record driving data of an appropriate length depending on the type of event that occurred while the vehicle 1 was traveling.

[0064] Furthermore, in the above embodiment or modification, the type of data items included in the travel data transmitted to the server or collected via an external interface, i.e., the travel data replicated and stored in the secondary replication memory, may be determined based on the type of event that occurred. For example, if the type of event that occurred is an accident, the determined data items include values representing the behavior of the vehicle 1, such as acceleration or angular velocity, values related to the driving operation or control of the vehicle 1, and an exterior image. If the type of event that occurred is a driver abnormality, the determined data items include values related to the driving operation or control of the vehicle 1 and an image of the driver. In this case, the second replication processing unit 24 identifies the type of data items to be included in the travel data by referencing the type of event detected and identified by the detection unit 23 and a table showing the relationship between the type of event and the type of data item. Such a table may be stored in advance in a storage area other than the storage area for travel data in the first non-volatile memory 13 or the second non-volatile memory 14. The second replication processing unit 24 then replicates and stores in the secondary replication memory, from the travel data stored in the primary replication memory, data items of the identified type for the second period. According to this modification, the running data recording device 5 can record running data including data items of an appropriate type according to the type of event that occurred while the vehicle 1 was running.

[0065] The driving data transmitted from the driving data recording device according to the above embodiment or modification to a server or collected via an external interface is used to analyze the cause of an event and to improve the driving assistance algorithm or the autonomous driving control algorithm of the vehicle. The improved driving assistance algorithm or the autonomous driving control algorithm may then be distributed from the server to various vehicles that use those algorithms.

[0066] A computer program that realizes the functions of the processor 15 of the driving data recording device 5 according to each of the above embodiments or variations may be provided in a form recorded on a computer-readable portable recording medium such as a semiconductor memory, a magnetic recording medium or an optical recording medium.

[0067] As described above, those skilled in the art can make various modifications to the embodiments within the scope of the present invention. [Explanation of symbols]

[0068] REFERENCE SIGNS LIST 1 vehicle, 2 behavior sensor, 3 camera, 4 wireless communication terminal, 5 driving data recording device, 6 ECU, 11 communication interface, 12 volatile memory, 13 first non-volatile memory, 14 second non-volatile memory, 15 processor, 21 storage processing unit, 22 first duplication processing unit, 23 detection unit, 24 second duplication processing unit, 25 transmission processing unit, 26 switching processing unit

Claims

1. a volatile memory; a first non-volatile memory; a second non-volatile memory; a storage processing unit that stores, in the volatile memory, travel data representing a situation of the vehicle or a situation around the vehicle while the vehicle is traveling; a first copy processing unit that copies and stores the traveling data for the first period stored in the volatile memory into one of the first non-volatile memory and the second non-volatile memory each time a first period elapses; a second copy processing unit that, when a save timing arrives after a predetermined time has elapsed since the timing at which the occurrence of a predetermined event is detected, copies the traveling data stored in the one of the nonvolatile memories, the traveling data for a second period that includes the timing at which the occurrence of the event is detected and is longer than the first period, from the one of the nonvolatile memories to the other of the first nonvolatile memory and the second nonvolatile memory, and stores the copied data; A driving data recording device having the same.

2. The driving data recording device of claim 1 further comprises a transmission processing unit that determines whether the amount of driving data for the second period is below a predetermined transmission upper threshold, and if the data amount is below the transmission upper threshold, transmits the driving data for the second period stored in the other non-volatile memory to another device via a communication terminal mounted on the vehicle at a transmission timing after the evacuation timing, while if the data amount exceeds the transmission upper threshold, transmits a collection request signal to the other device via the communication terminal requesting collection of the driving data for the second period.

3. The driving data recording device of claim 1 or 2 further comprises a switching processing unit that swaps the one nonvolatile memory with the other nonvolatile memory each time a switching period longer than the second period elapses or each time the number of times the driving data for the first period is stored in the one nonvolatile memory reaches a predetermined number of switching times.

4. a detection unit that detects the occurrence of the predetermined event and identifies the type of the event that has occurred; The driving data recording device according to claim 1 , wherein the second duplication processing unit determines the length of the second period depending on the type of the identified event.

5. a detection unit that detects the occurrence of the predetermined event and identifies the type of the event that has occurred; The driving data recording device according to claim 1 or 2, wherein the second replication processing unit determines the type of data items to be included in the driving data to be replicated and stored from the one non-volatile memory to the other non-volatile memory, depending on the type of the identified event.

6. storing, in a volatile memory, driving data representing a situation of the vehicle or an area around the vehicle while the vehicle is running; Each time a first period elapses, the traveling data for the first period stored in the volatile memory is copied and stored in one of a first non-volatile memory and a second non-volatile memory; When a predetermined time has elapsed since the timing of detecting the occurrence of a predetermined event, the travel data stored in the one of the nonvolatile memories is copied and stored in the other of the first nonvolatile memory and the second nonvolatile memory, the travel data including the timing of detecting the occurrence of the event and for a second period longer than the first period. A driving data recording method including:

7. storing, in a volatile memory, driving data representing a situation of the vehicle or an area around the vehicle while the vehicle is running; Each time a first period elapses, the traveling data for the first period stored in the volatile memory is copied and stored in one of a first non-volatile memory and a second non-volatile memory; When a predetermined time has elapsed since the timing of detecting the occurrence of a predetermined event, the travel data stored in the one of the nonvolatile memories is copied and stored in the other of the first nonvolatile memory and the second nonvolatile memory, the travel data including the timing of detecting the occurrence of the event and for a second period longer than the first period. A computer program for recording driving data that causes a processor installed in the vehicle to execute the above steps.

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