In-vehicle communication relay device and in-vehicle communication relay method

Abstract

The present invention provides an in-vehicle communication relay device and an in-vehicle communication relay method that can appropriately change the relay delay of the first message by feedforward-like changing the size threshold and timer threshold using other parameters without using the actual communication load. [Solution] An in-vehicle communication relay device that receives a first message from multiple devices via a first network, transmits a second message via a second network to a relay destination device, generates a second message containing one or more received first messages until the storage termination condition is met, determines that the storage termination condition has been met when the data size of the second message reaches a size threshold or when the elapsed time since the start of storage reaches a time threshold, and changes the size threshold and time threshold based on the driving conditions.

Description

Technical Field

[0001] This disclosure relates to an in-vehicle communication relay device and an in-vehicle communication relay method.

Background Art

[0002] Patent Document 1 discloses a relay device that stores first messages received from a plurality of devices via a first network into one second message and transmits the second message to a relay destination device. When the size of the second message reaches a size threshold or the elapsed time from the start of storage reaches a timer threshold, the relay device in Patent Document 1 ends the storage of the first message into the second message and transmits it to the relay destination device. When the communication load of at least one of the first network and the second network is low or medium, the relay device in Patent Document 1 sets the size threshold to a small value and sets the timer threshold to a small value. When the communication load is high, the relay device sets the size threshold to a large value and sets the timer threshold to a large value.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the technology of Patent Document 1, since the size threshold and the timer threshold are changed according to the actual communication load, when the communication load changes rapidly, the changes in the size threshold and the timer threshold are delayed, and there may be a delay in the relay. Also, in the technology of Patent Document 1, when the communication load is high, the timer threshold is set to a large value, so the storage time lag from the start of storage to the end increases, and there is a possibility that the relay delay of the first message increases.

[0005] Therefore, the purpose of this disclosure is to provide an in-vehicle communication relay device and an in-vehicle communication relay method that can appropriately change the relay delay of the first message by changing the size threshold and timer threshold in a feedforward manner using other parameters without using the actual communication load. [Means for solving the problem]

[0006] The in-vehicle communication relay device related to this disclosure is A first network communication unit that receives a first message via a first network from multiple devices, including a device that detects the surrounding conditions of the vehicle, A second message generation unit that generates a second message containing one or more of the first messages, A second network communication unit transmits the second message to a relay destination device via the second network, The system includes a driving condition acquisition unit that acquires the driving conditions of the vehicle, including one or both of the surrounding conditions of the vehicle and the driving conditions of the vehicle, The second message generation unit generates a second message by sequentially storing the first messages received after the previous storage termination condition was met, until the storage termination condition is met. When the data size of the second message reaches the size threshold, or when the elapsed time since the start of storage reaches the time threshold, it is determined that the storage termination condition has been met. The size threshold and the time threshold are changed based on the aforementioned driving conditions.

[0007] The in-vehicle communication relay method relating to this disclosure is: A first network communication step in which a first message is received via a first network from multiple devices, including a device that detects the surrounding conditions of the vehicle, A second message generation step of generating a second message containing one or more of the first messages, A second network communication step of transmitting the second message to a relay destination device via a second network, The system includes a driving condition acquisition step which acquires the driving conditions of the vehicle, including one or both of the surrounding conditions of the vehicle and the driving conditions of the vehicle, In the second message generation step, until the storage termination condition is met, a second message is generated by sequentially storing the first messages received after the previous storage termination condition was met. When the data size of the second message reaches the size threshold, or when the elapsed time since the start of storage reaches the time threshold, it is determined that the storage termination condition has been met. The size threshold and the time threshold are changed based on the aforementioned driving conditions. [Effects of the Invention]

[0008] According to the in-vehicle communication relay device and in-vehicle communication relay method described herein, a second message containing one or more first messages is generated and transmitted. This reduces the number of second messages compared to the number of first messages. The reduction in the number of second messages reduces the number of headers included in each second message and the amount of free data in the payload, thereby reducing the total communication volume of the second messages. Reducing the communication volume of the second messages reduces congestion on the second network line and reduces the transmission delay of the second messages. On the other hand, if the number of first messages per unit time is the same, as the number of first messages stored in the second message increases, a storage time lag occurs between the start and end of the storage period and the transmission of the received first message as a second message.

[0009] When the data size of the second message reaches the size threshold, or when the elapsed time since storage began reaches the time threshold, the storage of the first message is terminated and the second message is generated. If the number of first messages per unit time remains the same, as the size threshold increases, the number of first messages stored in the second message increases, and the total amount of second message communication per unit time decreases due to a decrease in the number of headers and the amount of free data in the payload. On the other hand, as the time threshold decreases, the upper limit of the storage time lag for the first message decreases.

[0010] The number of first messages per unit time received from multiple devices, including devices that detect the surrounding conditions of the vehicle, changes depending on the surrounding conditions of the vehicle or the driving conditions of the vehicle. Without using the actual communication load, the size threshold and time threshold are changed feedforward based on the driving conditions of the vehicle, including either or both of the surrounding conditions and the driving conditions of the vehicle. Therefore, depending on the driving conditions of the vehicle, it is possible to balance the decrease in the total communication volume of second messages due to an increase in the size threshold with the decrease in the upper limit of the storage time lag of the first message due to a decrease in the time threshold, and the relay delay of the first message can be appropriately changed feedforward. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic system configuration diagram of an in-vehicle communication relay device, multiple devices, a relay destination device, a first network, and a second network according to Embodiment 1. [Figure 2] This is a schematic block diagram of an in-vehicle communication relay device according to Embodiment 1. [Figure 3] This diagram illustrates the schematic hardware configuration of an in-vehicle communication relay device according to Embodiment 1. [Figure 4] This diagram illustrates the storage of multiple first messages into a second message according to Embodiment 1. [Figure 5]This is a diagram for explaining the setting of stepwise size thresholds and time thresholds based on the speed of the host vehicle according to Embodiment 1. [Figure 6] This is a diagram for explaining the setting of continuous size thresholds and time thresholds based on the speed of the host vehicle according to Embodiment 1. [Figure 7] This is a flowchart for explaining the processing of the in-vehicle communication relay device according to Embodiment 1. [Figure 8] This is a diagram for explaining the setting of size thresholds and time thresholds based on the type of driving area according to Embodiment 2. [Figure 9] This is a flowchart for explaining the processing of the in-vehicle communication relay device according to Embodiment 2. [Figure 10] This is a block diagram for explaining the calculation of the estimated value of the data volume of the first message using the learned model according to Embodiment 4. [Figure 11] This is a diagram for explaining the setting of stepwise size thresholds and time thresholds based on the estimated value of the data volume of the first message according to Embodiment 4. [Figure 12] This is a diagram for explaining the setting of continuous size thresholds and time thresholds based on the estimated value of the data volume of the first message according to Embodiment 4. [Figure 13] This is a flowchart for explaining the processing of the in-vehicle communication relay device according to Embodiment 4.

Embodiments for Implementing the Invention

[0012] 1. Embodiment 1 The in-vehicle communication relay device 1 according to Embodiment 1 will be described with reference to the drawings. The in-vehicle communication relay device 1 is mounted on a vehicle. The vehicle on which the in-vehicle communication relay device 1 is mounted is referred to as the host vehicle. FIG. 1 shows a schematic system configuration diagram of the in-vehicle communication relay device 1, a plurality of devices 3, a relay destination device 4, a first network 5, and a second network 6, etc.

[0013] The in-vehicle communication relay device 1 is connected to a plurality of devices 3 via the first network 5 and is connected to the relay destination device 4 via the second network 6.

[0014] <Multiple devices 3> Multiple devices 3 include devices that detect the surrounding conditions of the vehicle (hereinafter referred to as surrounding condition detection devices). In this embodiment, multiple devices 3 include a surrounding monitoring device 10 and a position detection device 11. The surrounding monitoring device 10 is the surrounding condition detection device.

[0015] The surrounding monitoring device 10 is a device that monitors the area around the vehicle, including cameras, radar, and sonar. The cameras include a front camera, a rear camera, and side cameras. Millimeter-wave radar and laser radar are used for the radar. Ultrasonic sonar is used for the sonar.

[0016] The camera comprises a camera body and a control device. The control device performs image processing on the captured image to determine the type and location of each object to be identified in the image, and transmits the determined type and location of each object to the in-vehicle communication relay device 1 via the first network 5. Objects to be identified include road surfaces, lane markings, road signs, road markings, vehicles, obstacles, people, and roadside objects.

[0017] As the number of objects detected by the camera increases, or as the time-dependent changes of the detected objects increase, the amount of data transmitted per unit time to the in-vehicle communication relay device 1 via the first network 5 increases. The transmitted data is divided into multiple first messages. A first message is the smallest transmission unit of data communicated on the first network 5. Therefore, as the number of detected objects increases, or as the time-dependent changes of the detected objects increase, the number of first messages per unit time increases. In addition, the number of detected objects or the time-dependent changes of the detected objects change according to the surrounding conditions of the vehicle or the driving conditions of the vehicle. Therefore, the number of first messages per unit time transmitted from the camera to the in-vehicle communication relay device 1 changes according to the surrounding conditions of the vehicle or the driving conditions of the vehicle.

[0018] The radar system comprises a radar unit and a control unit. The control unit calculates the position of an object that receives a reflected wave and transmits position information (e.g., 3D position information) to the in-vehicle communication relay device 1 via the first network 5. For example, the control unit transmits position information at a predetermined detection cycle. As the number of objects on or around the road within the detection range increases, the amount of 3D position information increases. Furthermore, as the time change of the objects increases, the time change of the 3D position information increases, and the amount of data per unit time transmitted to the in-vehicle communication relay device 1 via the first network 5 increases. Therefore, similar to a camera, the number of first messages per unit time transmitted from the radar to the in-vehicle communication relay device 1 changes depending on the surrounding conditions of the vehicle or the driving conditions of the vehicle.

[0019] The position detection device 11 is a device that detects the current position (latitude, longitude, and altitude) of the vehicle, and uses a GPS antenna or the like that receives signals output from artificial satellites such as GNSS (Global Navigation Satellite System). The position detection device 11 comprises a GPS antenna and a control device. The control device processes the signals from each artificial satellite received by the GPS antenna to calculate position information, and transmits the calculated position information to the in-vehicle communication relay device 1 via the first network 5. The control device transmits the position information to the in-vehicle communication relay device 1 via the first network 5 at a predetermined detection cycle.

[0020] <Network 1, 5> The first network 5 is a network that connects the in-vehicle communication relay device 1 and multiple devices 3. The communication protocol of the first network 5 is either the CAN (Controller Area Network) protocol or the CAN FD (Flexible Data rate) protocol, and the in-vehicle communication relay device 1 and the multiple devices 3 are connected by communication lines for CAN communication.

[0021] Other communication protocols besides the CAN protocol or CAN FD protocol may be used as the communication protocol for the first network 5. For example, FlexRay or LIN (Local Interconnect Network) may be used. Alternatively, Wi-Fi or BLE (Bluetooth Low Energy) may be used, and the in-vehicle communication relay device 1 and the multiple devices 3 may be connected wirelessly. The first network 5 may consist of multiple networks. The first network 5 is a general term for one or more networks that connect the in-vehicle communication relay device 1 and the multiple devices 3. In addition, devices other than the multiple devices 3 that are relay targets and send data to the relay destination device 4 via the in-vehicle communication relay device 1 may be connected to the first network 5.

[0022] <Second Network 6> The second network 6 is a network that connects the in-vehicle communication relay device 1 and the relay destination device 4. The second network 6 uses the Ethernet protocol as its communication protocol, and the in-vehicle communication relay device 1 and the multiple devices 3 are connected by communication lines for Ethernet communication.

[0023] Other communication protocols besides the Ethernet protocol may be used as the communication protocol for the second network 6. For example, FlexRay or LIN (Local Interconnect Network) may be used. Alternatively, Wi-Fi or BLE (Bluetooth Low Energy) may be used, and the in-vehicle communication relay device 1 and the relay destination device 4 may be connected wirelessly. In addition, devices other than the relay destination device 4 may be connected to the second network 6.

[0024] In this embodiment, the communication speed of the second network 6 is faster than the communication speed of the first network 5. For example, the CAN or CAN FD communication speed of the first network 5 is 500kbps or 2Mbps, and the Ethernet communication speed of the second network 6 is 1Gbps. The communication protocol of the first network 5 and the communication protocol of the second network 6 may be the same, but the communication speed of the second network 6 is set to be faster than the communication speed of the first network 5.

[0025] The maximum data size of the second message, which is the smallest transmission unit of data communicated in the second network 6, is greater than the maximum data size of the first message, which is the smallest transmission unit of data communicated in the first network 5. The data size of the second message ranges from 64 bytes to 1518 bytes when Ethernet is used, with a maximum data size of 1518 bytes. The maximum data size of the first message is 8 bytes or 64 bytes when CAN or CAN FD is used.

[0026] <Relay device 4> The relay destination device 4 is connected to the in-vehicle communication relay device 1 via the second network 6. The relay destination device 4 is connected to the second network 6 and includes a communication device that communicates using the communication protocol of the second network 6. The hardware configuration of the relay destination device 4 is the same as the hardware configuration of the in-vehicle communication relay device 1 shown in Figure 3, which will be described later.

[0027] The relay destination device 4 receives the second message, described later, from the in-vehicle communication relay device 1 via the second network 6. The relay destination device 4 unpacks one or more first messages contained in each second message and uses the unpacked first messages for various processing tasks.

[0028] In this embodiment, the first message includes the surrounding conditions of the vehicle and the vehicle's position. In this embodiment, the relay destination device 4 is a vehicle control device 4 that controls the vehicle's movement. Based on the surrounding conditions of the vehicle and the vehicle's position received from the in-vehicle communication relay device 1, the vehicle control device 4 performs various known automatic driving controls or driving assistance controls. In this process, the vehicle control device 4 uses map data of the area around the vehicle's position. The vehicle control device 4 obtains map data of the area around the vehicle's position from a map database stored in the vehicle control device 4's storage device or an external storage device.

[0029] The vehicle control device 4 calculates the target steering angle, target braking force, and target driving force of the wheels based on the surrounding conditions and position of the vehicle, using automatic driving control or driving assistance control. It then transmits the target steering angle to the electric steering device 12, the target braking force to the electric braking device 13, and the target driving force to the power unit 14. The electric steering device 12 includes a control device and a motor, etc. The electric braking device 13 includes a control device and an electric actuator, etc. The power unit 14 includes a control device and a power unit (motor, engine), etc. The vehicle control device 4 transmits each target value to each device via a third network 7 such as CAN or CAN FD.

[0030] <In-vehicle communication relay device 1> As shown in Figure 2, the in-vehicle communication relay device 1 includes functional units such as a first network communication unit 31, a second message generation unit 32, a second network communication unit 33, and a driving status acquisition unit 34. Each function of the in-vehicle communication relay device 1 is realized by the processing circuits provided in the in-vehicle communication relay device 1. Specifically, as shown in Figure 3, the in-vehicle communication relay device 1 includes a arithmetic processing unit 90 such as a CPU (Central Processing Unit), a storage device 91, a first network communication device 92, and a second network communication device 93.

[0031] The arithmetic processing unit 90 may include an ASIC (Application Specific Integrated Circuit), an IC (Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), a GPU (Graphics Processing Unit), various AI (Artificial Intelligence) chips, various logic circuits, and various signal processing circuits. Furthermore, multiple arithmetic processing units 90 of the same or different types may be provided, with each unit performing a portion of the processing. The storage device 91 may include various storage devices such as RAM (Random Access Memory), ROM (Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory), a hard disk, and an SSD (Solid State Drive). The first network communication device 92 is a communication device connected to the first network 5 and performing communication. The second network communication device 93 is a communication device connected to the second network 6 and performing communication.

[0032] Each function of the in-vehicle communication relay device 1, such as the functional units 31 to 34, is realized through the cooperation of the arithmetic processing unit 90, which executes software (programs) stored in the storage device 91, and the hardware such as the storage device 91, the first network communication device 92, and the second network communication device 93. Setting data such as size thresholds and time thresholds used by each functional unit 31 to 34 is stored in the storage device 91, such as an EEPROM.

[0033] The following provides a detailed explanation of each functional component. <First Network Communications Department 31> The first network communication unit 31 receives first messages from multiple devices 3, including peripheral state detection devices, via the first network 5. In this embodiment, the first network communication unit 31 controls the first network communication device 92 and communicates with the multiple devices 3 using the communication protocol of the first network 5. A first message is the smallest transmission unit of data communicated on the first network 5 and is called a frame or packet. A first message has a header that identifies the source and destination, etc., and a payload containing the data itself. In this embodiment, as described above, the communication protocol of the first network 5 is either the CAN or CAN FD protocol.

[0034] <Second Network Communications Department 33> The second network communication unit 33 transmits the second message generated by the second message generation unit 32 (described later) to the relay destination device 4 via the second network 6. In this embodiment, the second network communication unit 33 controls the second network communication device 93 and communicates with the relay destination device 4 using the communication protocol of the second network 6. The second message is the smallest unit of data transmitted in the second network 6 and is called a frame or packet.

[0035] As described above, the communication speed of the second network 6 is faster than that of the first network 5. In this embodiment, the Ethernet protocol is used as the communication protocol for the second network 6. The maximum data size of the second message is larger than the maximum data size of the first message. Therefore, multiple first messages can be stored in the second message.

[0036] <Driving status acquisition unit 34> The driving status acquisition unit 34 acquires the driving status of the vehicle, including either or both of the surrounding conditions of the vehicle and the driving status of the vehicle. In this embodiment, the driving status acquisition unit 34 acquires the speed of the vehicle as the driving status (driving state). For example, the driving status acquisition unit 34 calculates the speed of the vehicle based on the time change of the vehicle's position information received from the position detection device 11. Alternatively, the driving status acquisition unit 34 may acquire the speed of the vehicle from the relay destination device 4 (vehicle control device 4) via the second network 6.

[0037] <Second message generation unit 32> As shown in Figure 4, the second message generation unit 32 generates a second message containing one or more first messages. The second message generation unit 32 generates second messages containing the first messages received in order after the previous storage termination condition was met, until the storage termination condition is met. The second message generation unit 32 determines that the storage termination condition has been met when the data size of the second message reaches the size threshold, or when the elapsed time since the start of storage reaches the time threshold. The second message generation unit 32 changes the size threshold and the time threshold based on the driving conditions.

[0038] With this configuration, a second message containing one or more first messages is generated and sent, so the number of second messages can be reduced compared to the number of first messages. This reduction in the number of second messages reduces the number of headers and the amount of free data in the payload of each second message, thereby reducing the total amount of data transmitted for the second messages. Reducing the amount of data transmitted for the second messages alleviates congestion on the second network 6 and reduces the delay in transmitting the second messages. On the other hand, if the number of first messages per unit time is the same, as the number of first messages stored in the second message increases, a storage time lag occurs between the start and end of the storage period and the transmission of the received first message as a second message.

[0039] When the data size of the second message reaches the size threshold, or when the elapsed time since storage began reaches the time threshold, the storage of the first message is terminated and the second message is generated. If the number of first messages per unit time remains the same, as the size threshold increases, the number of first messages stored in the second message increases, and the total amount of second message communication per unit time decreases due to a decrease in the number of headers and the amount of free data in the payload. On the other hand, as the time threshold decreases, the upper limit of the storage time lag for the first message decreases.

[0040] As described above, the number of first messages per unit time received from multiple devices 3, including the surrounding state detection device, changes according to the surrounding state of the vehicle or the driving state of the vehicle. Without using the actual communication load, the size threshold and time threshold are changed feedforward based on the driving conditions of the vehicle, including either or both of the surrounding state of the vehicle and the driving state of the vehicle. Therefore, depending on the driving conditions of the vehicle, it is possible to balance the decrease in the total communication volume of second messages due to an increase in the size threshold with the decrease in the upper limit of the storage time lag of the first message due to a decrease in the time threshold, and the relay delay of the first message can be appropriately changed feedforward.

[0041] In this embodiment, the vehicle's speed is acquired as the driving condition (driving state), and the second message generation unit 32 continuously or gradually increases the size threshold and continuously or gradually decreases the time threshold as the vehicle's speed increases.

[0042] As described above, as the vehicle's speed increases, the time change of objects detected by the surrounding state detection device (in this example, the surrounding monitoring device 10) increases, and the number of first messages per unit time transmitted from each surrounding monitoring device 10 to the in-vehicle communication relay device 1 increases. Therefore, as the vehicle's speed increases, by continuously or gradually increasing the size threshold, the number of first messages stored in the second message can be increased, the total amount of second message communication can be reduced, and congestion on the second network 6 can be alleviated. On the other hand, increasing the size threshold may increase the storage time lag and potentially increase the relay delay, but as the vehicle's speed increases, by continuously or gradually decreasing the time threshold, the upper limit of the storage time lag for the first message can be reduced, thereby reducing the maximum relay delay due to the storage time lag. Therefore, without using the actual communication load, the relay delay of the first message can be reduced feedforward as the vehicle's speed increases. As the vehicle's speed increases, the required responsiveness of vehicle control increases, and the allowable relay delay of the first message decreases, and this requirement can be met.

[0043] For example, the second message generation unit 32 refers to table data in which the relationship between a plurality of speed ranges that increase step by step as shown in FIG. 5, and the size threshold value and time threshold value corresponding to each speed range is preset, and reads out the size threshold value and time threshold value set for the speed range corresponding to the current speed of the host vehicle. For example, when the speed of the host vehicle is within the range from SP3 to SP2, Sa3 and Ta3 are set as the size threshold value and time threshold value. When the speed of the host vehicle is within the range from SP2 to SP1, Sa2 and Ta2 are set as the size threshold value and time threshold value. When the speed of the host vehicle is within the range from SP1 to 0, Sa1 and Ta1 are set as the size threshold value and time threshold value. When the speed of the host vehicle is 0, Sa0 and Ta0 are set as the size threshold value and time threshold value. Note that SP3 > SP2 > SP1 > 0, Sa3 > Sa2 > Sa1 > Sa0 > 0, and 0 < Ta3 < Ta2 < Ta1 < Ta0. In this case, as the speed of the host vehicle increases, the second message generation unit 32 increases the size threshold value step by step and decreases the time threshold value step by step.

[0044] Alternatively, the second message generation unit 32 uses map data or a higher-order function (for example, a polynomial) in which the relationship between speed, size threshold value, and time threshold value is preset as shown in FIG. 6, and calculates the size threshold value and time threshold value corresponding to the current speed of the host vehicle. In this case, as the speed of the host vehicle increases, the second message generation unit 32 continuously increases the size threshold value and continuously decreases the time threshold value.

[0045] Note that in some speed intervals, the size threshold value or time threshold value may be continuously increased or decreased, and in some speed intervals, the size threshold value or time threshold value may be increased or decreased step by step, or a combination of continuous increase or decrease and stepwise increase or decrease may be used.

[0046] Next, the schematic processing procedure (in-vehicle communication relay method) of the in-vehicle communication relay device 1 will be described using the flowchart shown in FIG. 7. The processing of the flowchart in FIG. 7 is executed, for example, every predetermined calculation cycle.

[0047] In step S01, the driving status acquisition unit 34 acquires the driving status of the vehicle, including either or both of the surrounding conditions of the vehicle and the driving status of the vehicle. In this embodiment, as described above, the driving status acquisition unit 34 acquires the speed of the vehicle as the driving status (driving condition).

[0048] In step S02, as described above, the second message generation unit 32 changes the size threshold and the time threshold based on the driving conditions (in this example, the speed of the vehicle). In this embodiment, as the speed of the vehicle increases, the second message generation unit 32 continuously or gradually increases the size threshold and continuously or gradually decreases the time threshold.

[0049] In step S03, as described above, if the first network communication unit 31 receives a first message from multiple devices 3, including the peripheral state detection device, via the first network 5, it proceeds to step S04; otherwise, it proceeds to step S05.

[0050] In step S04, the second message generation unit 32 adds the received first message to the second message currently being stored. If there is no second message currently being stored, the second message generation unit 32 stores the received first message in a new second message and starts storing messages.

[0051] In step S05, as described above, the second message generation unit 32 determines whether the data size of the second message currently being stored has reached the size threshold. If the size threshold has been reached, it determines that the storage termination condition has been met and proceeds to step S07. If the size threshold has not been reached, it proceeds to step S06.

[0052] In step S06, as described above, the second message generation unit 32 determines whether the elapsed time since the start of storage has reached a time threshold. If the time threshold has been reached, it determines that the storage termination condition has been met and proceeds to step S07. If the time threshold has not been reached, it determines that the storage termination condition has not been met and terminates the process.

[0053] In step S07, the second message generation unit 32 determines that the storage termination condition has been met, and therefore terminates the storage of the first message into the second message and generates the final second message.

[0054] In step S08, the second network communication unit 33 transmits the second message generated in step S07 to the relay destination device 4 (vehicle control device 4) via the second network 6, and terminates the process.

[0055] 2. Embodiment 2 Next, the in-vehicle communication relay device 1 according to Embodiment 2 will be described. The same components as in Embodiment 1 will not be described. The basic configuration of the in-vehicle communication relay device 1 according to this embodiment is the same as in Embodiment 1, but the driving conditions used to set the size threshold and time threshold differ from those in Embodiment 1.

[0056] In this embodiment, the driving status acquisition unit 34 acquires map data of the area around the vehicle as driving status (surrounding conditions). For example, the driving status acquisition unit 34 acquires map data of the area around the vehicle's position from the map database based on the vehicle's position received from the position detection device 11. The map database is stored in a storage device connected via a network such as the first network 5 or the second network 6. Alternatively, the map database may be stored in the storage device 91 of the in-vehicle communication relay device 1. Alternatively, the driving status acquisition unit 34 may acquire map data of the area around the vehicle from the vehicle control device 4 via the second network 6. Map data specifically for determining the type of driving area may be acquired. The map data for determination stores the type of driving area corresponding to each position of the vehicle.

[0057] In this embodiment, the second message generation unit 32 determines the type of current driving area in which the vehicle is traveling based on the map data of the area around the vehicle acquired as driving conditions by the driving condition acquisition unit 34, and changes the size threshold and the time threshold according to the type of current driving area.

[0058] Depending on the type of driving area, the number of statistical objects present around the vehicle changes, and the number of statistical objects detected by the surrounding monitoring device 10 changes. Therefore, depending on the type of driving area, the number of first messages per unit time received from multiple devices 3, including the surrounding monitoring device 10, changes. Thus, without using the actual communication load, by changing the size threshold and the time threshold in a feedforward manner according to the type of driving area, it is possible to balance the decrease in the total amount of second messages communicated due to the increase in the size threshold with the decrease in the upper limit of the storage time lag for first messages due to the decrease in the time threshold, and the relay delay of first messages can be appropriately changed in a feedforward manner.

[0059] The number of statistical objects present around the vehicle changes depending on the type of driving area. In other words, the types of driving areas are set such that the number of statistical objects changes for each type of driving area. The second message generation unit 32 increases the size threshold and decreases the time threshold as the number of statistical objects corresponding to the current type of driving area increases.

[0060] With this configuration, as the number of statistical objects corresponding to the current type of driving area increases, the number of first messages per unit time transmitted from each peripheral monitoring device 10 to the in-vehicle communication relay device 1 increases. Therefore, as the number of statistical objects corresponding to the current type of driving area increases, increasing the size threshold increases the number of first messages stored in the second message, reducing the total amount of second messages communicated and alleviating congestion on the second network 6 lines. On the other hand, increasing the size threshold may increase the storage time lag and potentially increase the relay delay. However, as the number of statistical objects corresponding to the current type of driving area increases, decreasing the time threshold reduces the upper limit of the storage time lag for the first message, thereby reducing the maximum relay delay due to the storage time lag. Therefore, as the number of statistical objects corresponding to the current type of driving area increases, the relay delay of the first message can be reduced. As the number of statistical objects corresponding to the current type of driving area increases, the required responsiveness of vehicle control increases and the allowable relay delay of the first message decreases, and this requirement can be met.

[0061] For example, the types of driving areas may be urban areas, rural areas, or expressways. For example, the number of statistical objects in urban areas > the number of statistical objects in rural areas > the number of statistical objects on expressways. The second message generation unit 32 obtains the land use around the vehicle's driving road and the type of the vehicle's driving road from map data around the vehicle, and determines the type of the current driving area, such as an urban area, a rural area, or an expressway. Urban areas may be further subdivided according to the density of buildings, etc., and rural areas may be further subdivided according to population density, etc.

[0062] For example, the second message generation unit 32 refers to a table data set in advance, as shown in Figure 8, which contains a relationship between multiple types of driving areas and the size threshold and time threshold corresponding to each type of driving area, and reads the size threshold and time threshold corresponding to the current type of driving area. For example, if the current type of driving area is an urban area, Sb3 and Tb3 are set as the size threshold and time threshold. If the current type of driving area is a rural area, Sb2 and Tb2 are set as the size threshold and time threshold. If the current type of driving area is an expressway, Sb1 and Tb1 are set as the size threshold and time threshold. Note that Sb3 > Sb2 > Sb1 > 0, and 0 <Tb3<Tb2<Tb1である。

[0063] Next, the general processing procedure (in-vehicle communication relay method) of the in-vehicle communication relay device 1 will be explained using the flowchart shown in Figure 9. The processing in the flowchart of Figure 9 is executed, for example, at predetermined calculation cycles.

[0064] In step S11, the driving status acquisition unit 34 acquires the driving status of the vehicle, including either or both of the surrounding conditions of the vehicle and the driving status of the vehicle. In this embodiment, as described above, the driving status acquisition unit 34 acquires map data of the surroundings of the vehicle as the driving status (surrounding conditions).

[0065] In step S12, as described above, the second message generation unit 32 determines the type of the current driving area in which the vehicle is traveling based on map data of the area surrounding the vehicle, and changes the size threshold and time threshold according to the type of the current driving area. In this embodiment, the second message generation unit 32 increases the size threshold and decreases the time threshold as the number of statistical objects corresponding to the type of the current driving area increases.

[0066] In step S13, as described above, if the first network communication unit 31 receives a first message from multiple devices 3, including the peripheral state detection device, via the first network 5, it proceeds to step S14; otherwise, it proceeds to step S15.

[0067] In step S14, the second message generation unit 32 adds the received first message to the second message currently being stored. If there is no second message currently being stored, the second message generation unit 32 stores the received first message in a new second message and begins storage.

[0068] In step S15, as described above, the second message generation unit 32 determines whether the data size of the second message currently being stored has reached the size threshold. If the size threshold has been reached, it determines that the storage termination condition has been met and proceeds to step S17. If the size threshold has not been reached, it proceeds to step S16.

[0069] In step S16, as described above, the second message generation unit 32 determines whether the elapsed time since the start of storage has reached a time threshold. If the time threshold has been reached, it determines that the storage termination condition has been met and proceeds to step S17. If the time threshold has not been reached, it determines that the storage termination condition has not been met and terminates the process.

[0070] In step S17, the second message generation unit 32 determines that the storage termination condition has been met, and therefore terminates the storage of the first message into the second message and generates the final second message.

[0071] In step S18, the second network communication unit 33 transmits the second message generated in step S17 to the relay destination device 4 (vehicle control device 4) via the second network 6, and terminates the process.

[0072] 3. Embodiment 3 Next, the in-vehicle communication relay device 1 according to Embodiment 3 will be described. The same components as those in Embodiments 1 or 2 described above will be omitted from the description. The basic configuration of the in-vehicle communication relay device 1 according to this embodiment is the same as that of Embodiments 1 or 2, but it differs from Embodiments 1 or 2 in that the size threshold and the time threshold are changed based on multiple types of driving conditions.

[0073] The driving status acquisition unit 34 acquires multiple types of driving status. The second message generation unit 32 then calculates size thresholds and time thresholds corresponding to each type of driving status based on each type of driving status, sets the largest size threshold among the multiple size thresholds corresponding to the multiple types of driving status as the final size threshold, and sets the smallest time threshold among the multiple time thresholds corresponding to the multiple types of driving status as the final time threshold.

[0074] This configuration allows for setting a safe side size threshold and time threshold that minimizes the relay delay of the first message, from among multiple size thresholds and multiple time thresholds calculated in response to multiple types of driving conditions.

[0075] In this embodiment, the driving condition acquisition unit 34 acquires multiple types of driving conditions, including the vehicle's speed and map data of the vehicle's surroundings. The acquisition of the vehicle's speed and map data of the vehicle's surroundings is the same as in Embodiments 1 and 2, so a detailed explanation is omitted.

[0076] Similar to Embodiment 1, the second message generation unit 32 calculates a size threshold and a time threshold corresponding to the vehicle's speed based on the vehicle's speed. Also, similar to Embodiment 2, the second message generation unit 32 determines the type of the current driving area in which the vehicle is traveling based on map data of the area surrounding the vehicle, and calculates a size threshold and a time threshold corresponding to the type of driving area according to the type of driving area. The second message generation unit 32 then sets the largest size threshold among the size threshold corresponding to the vehicle's speed and the size threshold corresponding to the map data as the final size threshold, and sets the smallest time threshold among the time threshold corresponding to the vehicle's speed and the time threshold corresponding to the map data as the final time threshold.

[0077] 4. Embodiment 4 Next, the in-vehicle communication relay device 1 according to Embodiment 4 will be described. The same components as in Embodiment 1 will not be described. The basic configuration of the in-vehicle communication relay device 1 according to this embodiment is the same as in Embodiment 1, but it differs from Embodiment 1 in that the second message generation unit 32 sets the size threshold and time threshold using a trained model.

[0078] The second message generation unit 32 takes the driving conditions as input and uses a trained model that outputs an estimated value DTest of the amount of data of the first message per unit time received by the first network communication unit 31. The second message generation unit 32 inputs the current driving conditions into the trained model and calculates the estimated value DTest of the amount of data of the first message. As the estimated value DTest of the amount of data of the first message increases, the second message generation unit 32 continuously or gradually increases the size threshold and continuously or gradually decreases the time threshold.

[0079] With this configuration, since a trained model is used, the estimated data volume DTest of the first message can be accurately predicted for complex changes in driving conditions. As the estimated data volume DTest of the first message increases, the number of first messages stored in the second message can be increased by increasing the size threshold, reducing the total communication volume of the second message and alleviating congestion on the second network 6. On the other hand, increasing the size threshold may increase the storage time lag and thus increase the relay delay. However, as the estimated data volume DTest of the first message increases, the time threshold can be decreased, reducing the upper limit of the storage time lag for the first message and thus reducing the maximum relay delay due to the storage time lag. Therefore, as the estimated data volume DTest of the first message increases, the relay delay of the first message can be reduced. As the estimated data volume DTest of the first message increases, the required responsiveness of vehicle control increases and the acceptable relay delay of the first message decreases, and this requirement can be met.

[0080] In this embodiment, as shown in Figure 10, the second message generation unit 32 uses a trained model to which one or more (in this example, all) of the following information, acquired as driving conditions by the driving condition acquisition unit 34, is input: the speed of the vehicle, map data information of the area around the vehicle, date and time, and weather conditions around the vehicle.

[0081] The vehicle's speed, map data information around the vehicle, date and time, and weather all affect the number of objects detected by the surrounding condition detection device (in this example, the surrounding monitoring device 10) and how those objects change over time. Regarding the date and time, traffic volume, including vehicles and pedestrians, changes depending on whether it is a holiday, weekday, commuting time, daytime, or nighttime, which in turn changes the number of objects and how they change over time. Regarding the weather, for example, in the case of rain or snow, vehicle traffic volume increases, which changes the number of objects and how they change over time. By inputting multiple types of driving conditions that affect the number of objects and how they change over time into the trained model, the estimation accuracy of DTest, an estimate of the data volume of the first message, can be improved. In addition to the vehicle's speed, map data around the vehicle, date and time, and weather, various other driving conditions may also be input into the trained model.

[0082] Similar to Embodiment 2, information such as the type of area surrounding the vehicle's travel path (e.g., land use category) and the type of the vehicle's travel path are acquired as map data information for the area surrounding the vehicle and input into the trained model. For the date and time, for example, the date and time acquired by the position detection device 11 from satellite signals is used. For the weather, the weather determined from the camera image data may be used, or the weather acquired by the relay destination device 4, etc., from an external server via wireless communication may be used.

[0083] A machine learning model is used as the pre-trained model. Various well-known neural networks are used as the machine learning model. The pre-trained model is pre-trained using multiple datasets of pre-configured driving conditions (in this example, vehicle speed, map data information, date and time, and weather) and the amount of data of the first message per unit time. Well-known machine learning methods are used as the training method. The configuration constants of the pre-trained model are stored in a storage device 91 such as an EEPROM.

[0084] The trained model may be located on an external server. That is, the second message generation unit 32 may transmit the current driving status of its own vehicle to an external server, have the external server input the current driving status of its own vehicle into the trained model, have it calculate an estimated value DTest for the amount of data of the first message, and have it transmit the estimated value DTest for the amount of data of the first message to the second message generation unit 3. That is, the second message generation unit 3 may use the trained model on the external server to calculate the estimated value DTest for the amount of data of the first message.

[0085] The second message generation unit 32 refers to table data in which the relationship between the range of the estimated value DTest of the data amount of a plurality of first messages that increase step by step as shown in FIG. 11, the size threshold value and the time threshold value corresponding to each range is preset, and reads out the size threshold value and the time threshold value set for the range corresponding to the estimated value DTest of the data amount of the current first message. For example, when the estimated value DTest of the data amount of the first message is within the range from DT3 to DT2, Sc3 and Tc3 are set as the size threshold value and the time threshold value. When the estimated value DTest of the data amount of the first message is within the range from DT2 to DT1, Sc2 and Tc2 are set as the size threshold value and the time threshold value. When the estimated value DTest of the data amount of the first message is within the range from DT1 to 0, Sc1 and Tc1 are set as the size threshold value and the time threshold value. When the estimated value DTest of the data amount of the first message is 0, Sc0 and Tc0 are set as the size threshold value and the time threshold value. Note that DT3 > DT2 > DT1 > 0, Sc3 > Sc2 > Sc1 > Sc0 > 0, and 0 < Tc3 < Tc2 < Tc1 < Tc0. In this case, as the estimated value DTest of the data amount of the first message increases, the second message generation unit 32 increases the size threshold value step by step and decreases the time threshold value step by step.

[0086] Alternatively, the second message generation unit 32 uses map data or a higher-order function (for example, a polynomial) in which the relationship between the estimated value DTest of the data amount of the first message and the size threshold value and the time threshold value is preset as shown in FIG. 12, and calculates the size threshold value and the time threshold value corresponding to the estimated value DTest of the data amount of the current first message. In this case, as the estimated value DTest of the data amount of the first message increases, the second message generation unit 32 continuously increases the size threshold value and continuously decreases the time threshold value.

[0087] Note that in some of the estimated value intervals, the size threshold value or the time threshold value may be continuously increased or decreased, and in some of the estimated value intervals, the size threshold value or the time threshold value may be increased or decreased step by step, or a combination of continuous increase or decrease and stepwise increase or decrease may be used.

[0088] Next, the general processing procedure (in-vehicle communication relay method) of the in-vehicle communication relay device 1 will be explained using the flowchart shown in Figure 13. The processing in the flowchart of Figure 13 is executed, for example, at predetermined calculation cycles.

[0089] In step S21, the driving status acquisition unit 34 acquires the driving status of the vehicle, including either or both of the surrounding conditions of the vehicle and the driving status of the vehicle. In this embodiment, as described above, the driving status acquisition unit 34 acquires the speed of the vehicle, map data information of the surrounding area of ​​the vehicle, the date and time, and the weather around the vehicle as driving status.

[0090] In step S22, as described above, the second message generation unit 32 inputs the current driving conditions into a trained model that receives driving conditions as input and outputs an estimated value DTest of the amount of data of the first message per unit time received by the first network communication unit, and calculates the estimated value DTest of the amount of data of the first message. As the estimated value DTest of the amount of data of the first message increases, the second message generation unit 32 continuously or gradually increases the size threshold and continuously or gradually decreases the time threshold.

[0091] In step S23, as described above, if the first network communication unit 31 receives a first message from multiple devices 3, including the peripheral state detection device, via the first network 5, it proceeds to step S24; otherwise, it proceeds to step S25.

[0092] In step S24, the second message generation unit 32 adds the received first message to the second message currently being stored. If there is no second message currently being stored, the second message generation unit 32 stores the received first message in a new second message and begins storage.

[0093] In step S25, as described above, the second message generation unit 32 determines whether the data size of the second message currently being stored has reached the size threshold. If the size threshold has been reached, it determines that the storage termination condition has been met and proceeds to step S27. If the size threshold has not been reached, it proceeds to step S26.

[0094] In step S26, as described above, the second message generation unit 32 determines whether the elapsed time since the start of storage has reached a time threshold. If the time threshold has been reached, it determines that the storage termination condition has been met and proceeds to step S27. If the time threshold has not been reached, it determines that the storage termination condition has not been met and terminates the process.

[0095] In step S27, the second message generation unit 32 determines that the storage termination condition has been met, and therefore terminates the storage of the first message into the second message and generates the final second message.

[0096] In step S28, the second network communication unit 33 transmits the second message generated in step S27 to the relay destination device 4 (vehicle control device 4) via the second network 6, and terminates the process.

[0097] While this disclosure describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but are applicable individually or in various combinations to the embodiments. Accordingly, countless variations not illustrated herein are conceivable within the scope of the art disclosed herein. For example, these include modifying, adding or omitting at least one component, or even extracting at least one component and combining it with a component from another embodiment. [Explanation of symbols]

[0098] 1: In-vehicle communication relay device, 3: Multiple devices, 4: Relay destination device, 5: First network, 6: Second network, 31: First network communication unit, 32: Second message generation unit, 33: Second network communication unit, 34: Driving status acquisition unit

Claims

1. A first network communication unit that receives a first message via a first network from multiple devices, including a device that detects the surrounding conditions of the vehicle, A second message generation unit generates a second message containing one or more of the first messages, A second network communication unit transmits the second message to a relay destination device via the second network, The system includes a driving condition acquisition unit that acquires the driving conditions of the vehicle, including one or both of the surrounding conditions of the vehicle and the driving conditions of the vehicle, The second message generation unit generates a second message by sequentially storing the first messages received since the previous storage termination condition was met, until the storage termination condition is met. When the data size of the second message reaches the size threshold, or when the elapsed time since the start of storage reaches the time threshold, it is determined that the storage termination condition has been met. An in-vehicle communication relay device that changes the size threshold and the time threshold based on the aforementioned driving conditions.

2. The in-vehicle communication relay device according to claim 1, wherein the second message generation unit continuously or gradually increases the size threshold and continuously or gradually decreases the time threshold as the speed of the vehicle acquired as the driving conditions by the driving conditions acquisition unit increases.

3. The in-vehicle communication relay device according to claim 1, wherein the second message generation unit determines the type of current driving area in which the vehicle is traveling based on map data of the area around the vehicle acquired as the driving conditions by the driving conditions acquisition unit, and changes the size threshold and the time threshold according to the current type of driving area.

4. The statistical number of objects present around the vehicle varies depending on the type of driving area. The in-vehicle communication relay device according to claim 3, wherein the second message generation unit increases the size threshold and decreases the time threshold as the number of statistical objects corresponding to the current type of driving area increases.

5. The aforementioned driving status acquisition unit acquires multiple types of the aforementioned driving status, The in-vehicle communication relay device according to any one of claims 1 to 4, wherein the second message generation unit calculates a size threshold and a time threshold corresponding to each type of driving condition based on each type of driving condition, sets the largest of the multiple size thresholds corresponding to the multiple types of driving conditions as the final size threshold, and sets the smallest of the multiple time thresholds corresponding to the multiple types of driving conditions as the final time threshold.

6. The in-vehicle communication relay device according to claim 1, wherein the second message generation unit uses a trained model to which the driving conditions are input and an estimated value of the amount of data of the first message per unit time received by the first network communication unit is output, inputs the current driving conditions to the trained model to calculate the estimated amount of data, and as the estimated amount of data increases, continuously or gradually increases the size threshold and continuously or gradually decreases the time threshold.

7. The in-vehicle communication relay device according to claim 6, wherein the second message generation unit uses the learned model into which one or more of the following are input: the vehicle speed of the vehicle, map data information of the area around the vehicle, date and time, and weather conditions around the vehicle, which are acquired as the driving conditions by the driving conditions acquisition unit.

8. The in-vehicle communication relay device according to any one of claims 1 to 4, wherein the communication speed of the second network is faster than the communication speed of the first network, and the maximum data size of the second message is greater than the maximum data size of the first message.

9. A first network communication step in which a first message is received via a first network from multiple devices, including a device that detects the surrounding conditions of the vehicle, A second message generation step of generating a second message containing one or more of the first messages, A second network communication step of transmitting the second message to a relay destination device via a second network, The system includes a driving condition acquisition step which acquires the driving conditions of the vehicle, including one or both of the surrounding conditions of the vehicle and the driving conditions of the vehicle, In the second message generation step, until the storage termination condition is met, a second message is generated by sequentially storing the first messages received after the previous storage termination condition was met. When the data size of the second message reaches the size threshold, or when the elapsed time since the start of storage reaches the time threshold, it is determined that the storage termination condition has been met. An in-vehicle communication relay method that changes the size threshold and the time threshold based on the aforementioned driving conditions.

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