Vehicle Network

Abstract

To synchronize timing when data at an identical time is used in each reception device without increasing a cost while suppressing a delay to be low.SOLUTION: A delay information transmission part 21 calculates a reception delay time that is a difference between a transmission time and a reception time of received data, and transmits delay information expressing the calculated reception delay time to the other reception device. A data reception part 22 adds data received to an end of a buffer 22a in the case where the calculated reception delay time is a time less than the other longest device maximum delay time among the reception delay times expressed by the delay information received from the other reception device when the data is received. In the case where the calculated reception delay time is the time equal to or larger than the other device maximum delay time, the received data is used without being added to the buffer 22a. When a difference between the transmission time and a current time of the data stored in a head of the buffer 22a is the time equal to or larger than the other device maximum delay time, the data stored in the head of the buffer 22a is fetched and used.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a vehicle network in which a plurality of communication devices mounted on a vehicle are connected via communication lines. [Background technology]

[0002] Conventionally, examples of vehicle networks include AD / ADAS-compatible in-vehicle Ethernet networks that receive multiple data such as LiDAR data, camera images, and V2X communications using multiple receiving devices such as ECUs. Note that LiDAR is an abbreviation for Light Detection And Ranging, V2X is an abbreviation for Vehicle to everything (X), ECU is an abbreviation for Electric Control Unit, and AD / ADAS is an abbreviation for Automated Driving / Advanced Driver Assistance System. Also, Ethernet is a registered trademark.

[0003] In such an AD / ADAS-compatible vehicle network, it is desirable for each receiving device to synchronize the time at which processing is performed using data acquired at a specific time. However, due to delay differences caused by differences in data transmission paths, differences in the reception times of data acquired at the same time may occur between each receiving device. If each receiving device operates under such conditions, differences will occur between the timing at which data acquired at the same time is used, i.e., the time at which processing is performed using data acquired at the same time. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-223360 Summary of the Invention [Problem to be solved by the invention]

[0005] One possible solution to the above issues is to use conventional technologies such as AVB and TSN. AVB is an abbreviation for Audio Video Bridging, and TSN is an abbreviation for Time Sensitive Network. AVB synchronizes the display time of video and audio by including the shooting time and the designated time for display on the receiving side in the data section of the Ethernet frame from the sending side, and by always adding a certain margin to this designated time, it is possible to absorb delay differences.

[0006] However, when considering applying AVB to AD / ADAS-compatible vehicle networks, the following problem arises: While AD / ADAS-compatible vehicle networks require the lowest possible latency, the display latency in AVB is fixed to a set margin time, resulting in a problem of latency greater than the actual latency difference. On the other hand, while TSN makes it possible to achieve low-latency time synchronization between multiple devices, it also faces the problem of high performance requirements for the interface physical layer, which means that replacing existing devices with it would require significant costs.

[0007] The present invention has been made in consideration of the above circumstances, and its purpose is to provide a vehicle network that can synchronize the timing of using data at the same time between each receiving device while keeping delays low and without increasing costs. [Means for solving the problem]

[0008] The vehicle network described in claim 1 is configured such that a plurality of communication devices (2 to 7) mounted on a vehicle are connected via a communication line (8). In this case, each of the plurality of communication devices is configured to be able to synchronize time with each other. Here, among the plurality of communication devices, specific The communication device for transmitting data is a transmitter (2, 3, 10), and the specific Receiving data Used withIf the communication device is a receiving device (6, 7, 20, 30, 40, 50), the transmitting device is specific The time the data was acquired or specific The data is transmitted at a time when the transmission information is added. specific A data transmission unit (11) is provided for transmitting data.

[0009] The receiving device also includes a delay information transmitting unit (21, 31, 41) and a data receiving unit (22, 32, 52). specific The transmission time indicated by the transmission information added to the data and specific The data receiving unit calculates a reception delay time, which is the difference between the reception time and the time when the data was received, and transmits delay information representing the calculated reception delay time to another receiving device. specific receiving and using data, specific The system includes a buffer (22a) with a queue structure capable of storing data.

[0010] In the above configuration, the data receiving unit receives the specific When the data is received, if the reception delay time calculated by the delay information transmission unit is less than the other device maximum delay time, which is the longest time among the reception delay times represented by the delay information received from the other receiving device, the received data is specific data is added to the end of the buffer, and if the reception delay time calculated by the delay information transmission unit is equal to or longer than the maximum delay time of the other device, the received data is specific The data receiving unit uses the data without adding it to the buffer. specific When the difference between the transmission time indicated by the transmission information attached to the data and the current time becomes equal to or greater than the maximum delay time of the other device, specific Extract and use the data.

[0011] According to the above configuration, each receiving device can synchronize the timing of using data at the same time based on the receiving delay time of its own device and the receiving delay times of other devices indicated by delay information transmitted from the other receiving devices, so as to match the receiving device with the longest receiving delay time. In this case, there is no risk of excessive delay as in AVB, and there is no need for significant costs to replace existing devices as in TSN. Therefore, according to the above configuration, it is possible to achieve the excellent effect of keeping delay low and synchronizing the timing of using data at the same time between each receiving device without increasing costs. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram illustrating a network configuration according to a first embodiment. [Figure 2] FIG. 1 is a diagram illustrating a configuration of a transmission device according to a first embodiment. [Figure 3] FIG. 1 is a diagram schematically illustrating a configuration of a receiving device according to a first embodiment. [Figure 4] FIG. 10 is a diagram showing an example of the contents of a first process executed by the receiving device according to the first embodiment; [Figure 5] FIG. 10 is a diagram showing an example of the content of a second process executed by the receiving device according to the first embodiment; [Figure 6] FIG. 10 is a diagram showing an example of the content of a third process executed by the receiving device according to the first embodiment; [Figure 7] FIG. 10 is a diagram showing an example of a specific operation related to synchronization of the execution times of processes in each receiving device according to the first embodiment; [Figure 8] FIG. 10 is a diagram schematically illustrating the configuration of a receiving device according to a second embodiment. [Figure 9] FIG. 10 is a diagram showing an example of the contents of a first process executed by a receiving device according to a second embodiment; [Figure 10] FIG. 10 is a diagram showing an example of the content of a third process executed by the receiving device according to the second embodiment. [Figure 11] FIG. 10 is a diagram illustrating a configuration of a receiving device according to a third embodiment. [Figure 12]FIG. 11 is a diagram showing an example of the contents of a first process executed by a receiving device according to a third embodiment; [Figure 13] FIG. 10 is a diagram showing an example of the content of a third process executed by the receiving device according to the third embodiment. [Figure 14] FIG. 10 is a diagram illustrating a configuration of a receiving device according to a fourth embodiment. [Figure 15] FIG. 10 is a diagram showing an example of the contents of a first process executed by a receiving device according to a fourth embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, several embodiments will be described with reference to the drawings. Note that substantially the same components in the respective embodiments will be denoted by the same reference numerals, and the description thereof will be omitted. (First embodiment) The first embodiment will be described below with reference to FIGS.

[0014] As shown in Fig. 1, network 1 of this embodiment is an example of a vehicle network, in which a camera 2, LiDAR 3, pre-processing ECU 4, sub-ECU 5, control ECU 6, and control ECU 7 mounted on a vehicle such as an automobile are connected via communication lines 8. Each of camera 2, LiDAR 3, pre-processing ECU 4, sub-ECU 5, control ECU 6, and control ECU 7 has a clock synchronized by means of gPTP or the like, thereby enabling the time to be synchronized with one another. PTP is an abbreviation for Precision Time Protocol.

[0015] The camera 2, LiDAR 3, pre-processing ECU 4, sub-ECU 5, control ECU 6, and control ECU 7 function as communication devices, and perform Ethernet communication via a communication line 8. If, among these multiple communication devices, a communication device that transmits data via the communication line 8 is defined as a transmitting device, and a communication device that receives data via the communication line 8 is defined as a receiving device, then the camera 2 and LiDAR 3 function as a transmitting device, and the control ECU 6 and control ECU 7 function as a receiving device.

[0016] The above-described transmitting device and receiving device may have the configurations shown in Fig. 2 and Fig. 3, for example. As shown in Fig. 2, the transmitting device 10 includes functional blocks such as a data transmitting unit 11. The data transmitting unit 11 transmits data after adding transmission information indicating a transmission time, which is the time at which the data is to be transmitted. Note that, in cases where the delay time between when the transmitting device 10 acquires the data and when it transmits it is extremely short, the time when the data was acquired can also be used as the transmission time.

[0017] 3, the receiving device 20 includes functional blocks such as a delay information transmitting unit 21 and a data receiving unit 22. The delay information transmitting unit 21 calculates a reception delay time, which is the difference between the transmission time indicated by the transmission information added to the received data and the reception time, which is the time when the data was received. The delay information transmitting unit 21 then transmits, i.e., broadcasts, the delay information indicating the calculated reception delay time to all other receiving devices.

[0018] In this case, the delay information transmitting unit 21 is configured to periodically transmit the delay information at a predetermined specified time interval. The delay information transmitting unit 21 is provided with a timer 21a for counting the specified time. The interval at which the delay information transmitting unit 21 transmits the delay information, i.e., the specified time, can be set to a different time for each receiving device 20. The delay information transmitting unit 21 can also transmit the delay information when it receives data transmitted from the transmitting device 10.

[0019] The data receiving unit 22 receives and uses data transmitted from the transmitting device 10. In this specification, the data transmitted from the transmitting device 10 is sometimes referred to as input data. The data receiving unit 22 has a queue structure capable of storing input data, that is, a first-in, first-out type buffer 22a. In this specification, the buffer 22a is sometimes referred to as a queue.

[0020] The data receiving unit 22 is also configured to receive delay information, which is data representing reception delay information transmitted from other receiving devices. Note that in this specification, delay information transmitted from other receiving devices is sometimes referred to as other device delay information. The data receiving unit 22 is equipped with a storage unit 22b that stores other device delay information. The data receiving unit 22 is configured to store other device delay information transmitted from the same other receiving device in a manner that overwrites previous information so that the most recent information remains in the storage unit 22b. As a result, the latest other device delay information for each other receiving device is stored in the storage unit 22b.

[0021] When data receiving unit 22 receives data transmitted from transmitting device 10, if the reception delay time of its own device calculated by delay information transmitting unit 21 is less than the other device maximum delay time, which is the longest time among the reception delay times represented by other device delay information, which is delay information received from other receiving devices, data receiving unit 22 adds the received data to the end of buffer 22a, and if the reception delay time of its own device calculated by delay information transmitting unit 21 is equal to or greater than the other device maximum delay time, data receiving unit 22 uses the received data without adding it to buffer 22a. When the difference between the transmission time represented by the transmission information added to the data stored at the top of buffer 22a and the current time becomes equal to or greater than the other device maximum delay time, data receiving unit 22 retrieves and uses the data stored at the top of buffer 22a.

[0022] Each functional block of the transmitting device 10 and the receiving device 20 is realized by a CPU of the transmitting device 10 and the receiving device 20 executing a computer program stored in a non-transitory physical storage medium and performing processing corresponding to the computer program, that is, by software. Note that at least a part of each functional block may be realized by hardware.

[0023] The camera 2 captures images of the area ahead of the vehicle, and transmits data A representing the captured image of the area ahead of the vehicle to the pre-processing ECU 4 and the control ECU 7 after being assigned transmission information. The LiDAR 3 measures the position of objects ahead of the vehicle, and transmits data B representing object position information obtained by the measurement to the sub-ECU 5 after being assigned transmission information. The pre-processing ECU 4 is an ECU for image pre-processing, and receives data A. The pre-processing ECU 4 recognizes the type of object in the received data A, and transmits data A' representing object recognition information obtained by the recognition to the sub-ECU 5. Examples of object types include a preceding vehicle and a pedestrian. In this case, the same transmission information as that assigned to data A is assigned to data A'.

[0024] The sub-ECU 5 functions as a switching hub and combines multiple signals transmitted from the LiDAR 3, which is a sensor, and the pre-processing ECU 4, which is another ECU, to the control ECU 6 into one path. That is, the sub-ECU 5 receives data A' and data B, and transmits data A'' and data B' corresponding to the received data to the control ECU 6. In this case, data A'' is assigned the same transmission information as that assigned to data A and A', and data B' is assigned the same transmission information as that assigned to data B.

[0025] The control ECU 6 is a control ECU for creating a driving plan, and receives data A'' and data B'. The control ECU 6 links data A'' representing object recognition information with data B' representing object position information, and recognizes the situation ahead of the vehicle based on the link, and determines a driving pattern. In this case, performing the process of determining the driving pattern corresponds to using data A'' and data B'.

[0026] The control ECU 7 is a control ECU for preventing lane departure, and detects the lane position from data A representing an image in front of the vehicle, and performs processing to intervene in steering operation when the vehicle deviates from the lane based on the detected lane position so as to eliminate the lane departure. In this case, performing processing to intervene in steering operation corresponds to using data A.

[0027] In the above configuration, a steering control unit (not shown) that controls the steering of the vehicle is configured to receive steering control commands transmitted from both the control ECU 6 and the control ECU 7. In this embodiment, the steering control unit has a determination criterion such that when commands are received simultaneously from both the control ECU 6 and the control ECU 7, the command from the control ECU 6 is given priority.

[0028] In this configuration, for example, if an obstacle is present ahead of the vehicle and the driver, i.e., the operator of the vehicle, performs a steering operation to temporarily deviate from the lane to avoid the obstacle, the control ECU 6 recognizes the obstacle and issues a command to the steering control unit to execute an operation to avoid the obstacle, and the control ECU 7 detects only the lane departure and issues a command to the steering control unit to execute an operation to return the vehicle to the original lane. In this case, the steering control unit has a determination criterion that prioritizes the command from the control ECU 6, and therefore can prioritize the operation to avoid the obstacle.

[0029] Next, the contents of the processing performed by the receiving device 20 in the above configuration, that is, the control ECU 6 and the control ECU 7, will be described with reference to Figures 4 to 6. Each receiving device 20 performs first processing, second processing, and third processing in parallel.

[0030] <Regarding the first treatment> The first process is, for example, a process shown in Fig. 4, and is a process related to the use or storage of received data. The first process is executed every time data is received by the data receiving unit 22. First, in step S101, it is determined whether the received data is input data, which is data transmitted from the transmitting device 10.

[0031] Here, if the received data is not input data, that is, if the received data is other device delay information, the result in step S101 is "NO" and the process proceeds to step S102. In step S102, the received other device delay information is stored in memory unit 22b. After step S102 is executed, this process ends. On the other hand, if the received data is input data, the result in step S101 is "YES" and the process proceeds to step S103.

[0032] In step S103, the reception delay time of the currently received input data is calculated. That is, in step S103, the delay information transmission unit 21 calculates the reception delay time of the input data. After step S103 is executed, the process proceeds to step S104, where it is determined whether the reception delay time Ta of the own device calculated in step S103 is equal to or longer than the other device maximum delay time Tb, which is the longest time among the reception delay times represented by the other device delay information stored in storage unit 22b. In other words, in step S104, it is determined whether the reception delay time Ta of the own device is equal to or longer than the other device maximum delay time Tb.

[0033] Here, if the reception delay time Ta of the own device is equal to or greater than the maximum delay time Tb of the other device, the answer in step S104 becomes "YES" and the process proceeds to step S105. In other words, if the transmission time of the input data received this time is the same as or later than the transmission time of the input data received by the other receiving device, the answer in step S104 becomes "YES" and the process proceeds to step S105. In step S105, a process using the input data received this time is executed. The process using the input data is a process for determining a driving pattern in the case of the control ECU 6, and a process for intervening in a steering operation in the case of the control ECU 7.

[0034] That is, in this case, the data receiving unit 22 uses the currently received input data without adding it to the queue. On the other hand, if the reception delay time Ta of the own device is less than the maximum delay time Tb of other devices, the answer is "NO" in step S104, and the process proceeds to step S106. In step S106, the currently received input data is added to the end of the queue. After step S105 or S106 is executed, this process ends.

[0035] <Regarding the second treatment> The second process is, for example, a process as shown in Fig. 5, and is a process related to retrieving received data. The second process is a process that starts when the receiving device 20 is started. Specifically, the second process is a process that starts when the vehicle is initialized when the power is turned on.

[0036] First, in step S201, the difference between the current time and the transmission time indicated by the transmission information attached to the data stored at the head of the queue is calculated, i.e., the reception delay time of the data stored at the head of the queue. After step S201 is executed, the process proceeds to step S202, where it is determined whether the reception delay time Tc of the data stored at the head of the queue is equal to or longer than the maximum other device delay time Tb. In other words, in step S202, it is determined whether the reception delay time Tc of the data stored at the head of the queue is equal to or longer than the maximum other device delay time Tb.

[0037] Here, if the reception delay time Tc of the data stored at the head of the queue is less than the other device's maximum delay time Tb, the result is "NO" in step S202, and the determination of step S202 is executed again. On the other hand, if the reception delay time Tc of the data stored at the head of the queue is equal to or greater than the other device's maximum delay time Tb, the result is "YES" in step S202, and the process proceeds to step S203. In other words, if the transmission time of the data stored at the head of the queue is not earlier than the transmission time of the input data received by the other receiving device, the result is "YES" in step S202, and the process proceeds to step S203.

[0038] In step S203, the data stored at the head of the queue is retrieved. After step S203 is executed, the process proceeds to step S204, where a process using the data retrieved in step S203 is executed. The process using the retrieved data is, as in step S105, a process for determining a driving pattern in the case of the control ECU 6, and a process for intervening in a steering operation in the case of the control ECU 7. After step S204 is executed, the process returns to step S201, and the same processes as those described above are repeated.

[0039] <About the third treatment> The third process is, for example, a process as shown in Fig. 6, and is a process related to transmission of delay information indicating a reception delay time. The third process is a process that is started when the receiving device 20 is started. Specifically, the third process is a process that is started when the vehicle is initialized by turning on the power.

[0040] First, in step S301, the timer 21a starts timing. After step S301 is executed, the process proceeds to step S302, where it is determined whether the timer time Td, which is the time measured by the timer 21a, is equal to or greater than the specified time Te. If the timer time Td is less than the specified time Te, the result in step S302 is "NO," and the determination in step S302 is executed again. On the other hand, if the timer time Td is equal to or greater than the specified time Te, the result in step S302 is "YES," and the process proceeds to step S303.

[0041] In step S303, the difference between the transmission time indicated by the transmission information attached to the data stored at the head of the queue and the current time, i.e., the reception delay time of the data stored at the head of the queue, is calculated. After step S303 is executed, the process proceeds to step S304, where delay information indicating the reception delay time calculated in step S303 is transmitted to all other receiving devices. In other words, in step S304, the delay information is broadcast. After step S304 is executed, the process proceeds to step S305, where the timer 21a is reset. After step S305 is executed, the process returns to step S301, and the same processes as those described above are repeated.

[0042] Next, an example of a specific operation relating to synchronization of the execution times of the processes in the control ECU 6 and the control ECU 7, which function as the receiving device 20, will be described with reference to FIG. As shown in Fig. 1, each piece of data transmitted from the camera 2 and the LiDAR 3 functioning as the transmitting device 10 is provided to the control ECU 6 and the control ECU 7 via a plurality of different paths. As shown in Fig. 7, the data received by the control ECU 6 and the control ECU 7 at a given time t have different assigned transmission times due to the differences in the paths described above.

[0043] In Figure 7, data frames are represented by rectangles, with numbers such as 01, 02, 03, 04, 05, 06, 07, and 08 written inside them to indicate the time the data was sent. Note that smaller numbers represent earlier times. In this case, open rectangles represent data stored in buffer 22a, and dotted-line filled rectangles represent data referenced at that time, i.e., data used at that time.

[0044] As shown in FIG. 7, when the current time t is "05", the transmission times of data A" and B' received by the control ECU 6 are "01" and "02", respectively, and the transmission time of data A received by the control ECU 7 is "03". When the current time t is "06", the transmission times of data A" and B' received by the control ECU 6 are "02" and "03", respectively, and the transmission time of data A received by the control ECU 7 is "04".

[0045] In this case, the transmission time of data A'' in the control ECU 6 is delayed by "01" relative to the transmission time of data B'. Therefore, in order to align the times of data A'' and data B'', data B' is stored in the buffer 22a, and when the current time t is "06", the data is retrieved from the buffer 22a and referenced. In this way, the transmission times of data A'' and B' used in the control ECU 6 are aligned. At this time, the control ECU 6 broadcasts delay information indicating the reception delay time Δt1 of its own device, which is expressed by the following equation (1). Δt1=06-02=4 …(1)

[0046] When the control ECU 7 receives the broadcast delay information, it compares the reception delay time Δt1 indicated by the delay information with the reception delay time Δt2 of its own device expressed by the following equation (2). Δt2=06-04=2 …(2)

[0047] As a result of the comparison, the control ECU 7 determines that the reception delay time Δt2 is shorter than the reception delay time Δt1, and therefore determines that its own device has less delay. Thereafter, the control ECU 7 stores the data A in the buffer 22a, and begins to retrieve and refer to the data from the buffer 22a when the reception delay time Δt2 of the data stored at the beginning of the buffer 22a becomes equal to the reception delay time Δt1. In this case, when the current time t is "08," the reception delay time Δt2 of the data stored at the beginning of the buffer 22a of the control ECU 7 becomes equal to the reception delay time Δt1 indicated by the delay information transmitted from the control ECU 6.

[0048] As a result, when the current time t is "08", the transmission times of all data used by the control ECU 6 and the control ECU 7, i.e., data A'', data B' and data A, are all the same at "04". In this way, the control ECU 6 and the control ECU 7 use data from the same time at the same time, and the execution times of the processes are synchronized.

[0049] According to the present embodiment described above, the following effects can be obtained. When data receiving unit 22 receives data transmitted from transmitting device 10, if the reception delay time calculated by delay information transmitting unit 21 is less than the other device maximum delay time, which is the longest reception delay time indicated by the delay information received from other receiving devices, data receiving unit 22 adds the received data to the end of buffer 22a, and if the reception delay time calculated by delay information transmitting unit 21 is equal to or greater than the other device maximum delay time, data receiving unit 22 uses the received data without adding it to buffer 22a. Furthermore, when the difference between the transmission time indicated by the transmission information added to the data stored at the beginning of buffer 22a and the current time becomes equal to or greater than the other device maximum delay time, data receiving unit 22 retrieves and uses the data stored at the beginning of buffer 22a.

[0050] According to the above configuration, each receiving device 20 can synchronize the timing of using data at the same time so as to match the receiving device 20 with the longest reception delay time, based on the reception delay time of the receiving device itself and the reception delay times of other devices indicated by delay information transmitted from the other receiving devices. In this case, there is no risk of excessive delay as in AVB, and no significant cost is required to replace existing devices as in TSN. Therefore, according to this embodiment, it is possible to obtain the excellent effect of keeping delay low and synchronizing the timing of using data at the same time between each receiving device 20 without increasing costs.

[0051] In the configuration of this embodiment, if the execution times of processes between the control ECU 6 and the control ECU 7 that function as the receiving device 20 are not synchronized and the timing at which data at the same time is used is delayed in the control ECU 6 compared to the control ECU 7, the following problem will occur. That is, as described above, in the configuration of this embodiment, for example, if there is an obstacle ahead of the vehicle and the driver of the vehicle performs a steering operation that causes the vehicle to temporarily deviate from the lane to avoid the obstacle, the control ECU 6 will recognize the obstacle and provide a command to the steering control unit to execute an operation to avoid the obstacle, and the control ECU 7 will detect only the lane departure and provide a command to the steering control unit to execute an operation to return the vehicle to the original lane.

[0052] When such operational control is assumed, if the timing of using data at the same time is later in the control ECU 6 than in the control ECU 7 as described above, the steering control unit will be given a steering control command from the control ECU 7 before the steering control command from the control ECU 6, and as a result, unintended behavior will occur, such as temporarily intervening in the steering operation to return the vehicle to the original lane where the obstacle is present.

[0053] In contrast to this, according to this embodiment, the execution times of the processes between the control ECU 6 and the control ECU 7 are synchronized, so that the steering control command from the control ECU 7 is not given to the steering control unit before the steering control command from the control ECU 6. In this case, the steering control command from the control ECU 6 and the steering control command from the control ECU 7 are given to the steering control unit simultaneously, but as described above, when the steering control unit receives commands from both the control ECU 6 and the control ECU 7 simultaneously, the command from the control ECU 6 takes priority, so that the occurrence of the above-mentioned unintended behavior is prevented.

[0054] The delay information transmitting unit 21 is configured to transmit the delay information periodically at predetermined time intervals. This provides the following advantages compared to when the delay information is transmitted upon receiving data transmitted from the transmitting device 10. That is, if the delay information is transmitted upon receiving data from each receiving device 20, there is a high possibility that the timing of broadcasting the delay information will conflict among multiple receiving devices 20.

[0055] In contrast, when the delay information is transmitted periodically at specified time intervals as in the present embodiment, it is possible to reduce the possibility of collisions in the timing of broadcasting the delay information between multiple receiving devices 20. In this case, it is also possible to set the specified time differently for each receiving device 20, which further reduces the possibility of collisions.

[0056] (Second embodiment) The second embodiment will be described below with reference to FIGS. As shown in Figure 8, the receiving device 30 of this embodiment differs from the receiving device 20 of the first embodiment shown in Figure 3 in that it has a delay information transmitting unit 31 instead of the delay information transmitting unit 21, and a data receiving unit 32 instead of the data receiving unit 22.

[0057] Like the data receiving unit 22, the data receiving unit 32 can receive data transmitted from the transmitting device 10 and delay information transmitted from other receiving devices, and can also receive data representing change notifications for notifying changes in the network configuration. The change notifications indicate that there has been a change or modification in the configuration of at least one of the multiple communication devices and communication lines 8 that make up the network 1. Such change notifications are sent manually or automatically by logic or the like when one or both of the hardware and software related to the network 1 are changed, for example, due to a service update or the like.

[0058] The delay information transmitting unit 31, like the delay information transmitting unit 21, calculates a reception delay time and transmits delay information indicating the calculated reception delay time to all other receiving devices. However, the delay information transmitting unit 31 does not include the timer 21a compared to the delay information transmitting unit 21, and therefore the timing at which the delay information is transmitted is different. In other words, the delay information transmitting unit 31 transmits the delay information upon receiving the above-mentioned change notification.

[0059] The receiving device 30 having the above configuration is configured to perform the first process, the second process, and the third process, similar to the receiving device 20 of the first embodiment, but the contents of the first process and the third process are different from those of the first embodiment. In this case, the third process is included as part of the first process. The contents of the first process and the third process performed by the receiving device 30 of this embodiment will be described below with reference to Figures 9 and 10.

[0060] [1] First process As shown in Fig. 9, the first process of this embodiment differs from the first process of the first embodiment shown in Fig. 4 in that steps S111 and S112 are added. In the first process of this embodiment, if step S101 returns "NO," that is, if the received data is not input data, the process proceeds to step S111. In step S111, it is determined whether the received data is other device delay information.

[0061] Here, if the received data is other device delay information, the result in step S111 is "YES" and the process proceeds to step S102. On the other hand, if the received data is not other device delay information, that is, if the received data is a change notification, the result in step S111 is "NO" and the process proceeds to step S112. In step S112, a third process is executed. After step S112 is executed, this process ends.

[0062] [2] Third Processing As shown in Fig. 10, the third process of this embodiment differs from the third process of the first embodiment shown in Fig. 6 in that steps S301, S302, and S305 are omitted. When the third process of this embodiment starts, step S303 is executed first. In step S303, the reception delay time of the data stored at the head of the queue is calculated. After step S303 is executed, the process proceeds to step S304, where delay information indicating the reception delay time calculated in step S303 is broadcast. After step S304 is executed, this process ends.

[0063] As described above, the delay information transmitter 31 of this embodiment is configured to transmit delay information upon receiving a change notification indicating that there has been a change or alteration in the configuration of at least one of the multiple communication devices and communication lines 8 that make up the network 1. This configuration provides the following advantages: In other words, in the network 1, which is an example of a vehicle network in which Ethernet communication is performed via the communication lines 8, it is unlikely that the delay between the same routes will change significantly unless there is a change in the components, that is, the multiple communication devices and communication lines 8.

[0064] That is, in the network 1, unless there is a change in the components, the reception delay time at each receiving device 30 will not change significantly and will be roughly constant. Therefore, if delay information is transmitted when data transmitted from the transmitting device 10 is received, the frequency of broadcasting will increase, which may increase the processing load on the receiving device 30. In contrast, if delay information is transmitted when a change notification is received, as in the present embodiment, the frequency of broadcasting can be kept low, and as a result, the processing load on the receiving device 30 can be reduced.

[0065] (Third embodiment) The third embodiment will be described below with reference to FIGS. As shown in Figure 11, the receiving device 40 of this embodiment differs from the receiving device 20 of the first embodiment shown in Figure 3 in that it has a delay information transmitting unit 41 instead of the delay information transmitting unit 21.

[0066] The delay information transmitting unit 41, like the delay information transmitting unit 21, calculates a reception delay time and transmits delay information representing the calculated reception delay information. Also, like the delay information transmitting unit 21, the delay information transmitting unit 41 is configured to periodically transmit delay information at predetermined time intervals. However, the delay information transmitting unit 41 is configured to transmit delay information only to a synchronization target device, which is a device designated in advance among other receiving devices.

[0067] The synchronization target devices can be specified, for example, as follows: That is, there is very little need to synchronize the execution times of processes between ECUs of a vehicle control system that execute controls related to vehicle driving, such as brake control and accelerator control, and ECUs of an entertainment control system that execute controls unrelated to vehicle driving, such as control of a navigation device, display device, and audio.

[0068] Considering the above points, the ECUs for the vehicle control system are grouped together, and the ECUs for the entertainment control system are grouped together. Then, for each of these groups, each ECU in the group designates all of the other ECUs in the group as synchronization target devices, thereby enabling synchronization of the execution times of processes among the ECUs in the group. Note that there are also receiving devices in a vehicle, such as an ECU that adjusts power mirrors, that do not require synchronization of the execution times of processes with other receiving devices. Such receiving devices can simply be left unassigned.

[0069] The receiving device 40 having the above configuration is configured to perform the first process, the second process, and the third process in parallel, similar to the receiving device 20 of the first embodiment, but the contents of the first process and the third process are different from those of the first embodiment. The contents of the first process and the third process performed by the receiving device 40 of this embodiment will be described below with reference to Figs. 12 and 13.

[0070] <Regarding the first treatment> As shown in Fig. 12, the first process of this embodiment differs from the first process of the first embodiment shown in Fig. 4 in that step S121 is added. In the first process of this embodiment, if step S101 returns "NO," that is, if the received data is not input data, the process proceeds to step S121. In step S121, it is determined whether the received data is other device delay information transmitted from a synchronization target device.

[0071] If the received data is not other device delay information transmitted from the synchronization target device, that is, if the received data is other device delay information transmitted from a device other than the synchronization target device, the result in step S121 is "NO" and the process ends without proceeding to step S102. On the other hand, if the received data is other device delay information transmitted from the synchronization target device, the result in step S121 is "YES" and the process proceeds to step S102.

[0072] The first process of this embodiment can be changed to the same process as the first process of the first embodiment shown in Fig. 4, that is, it can be changed to omit step S121. Even if changed in this way, no problem will occur as long as the delay information is transmitted only to the synchronization target device by executing the third process of this embodiment, which will be described later, in each receiving device 40.

[0073] However, there is a possibility that delay information may be transmitted to a device other than the synchronization target device for some reason. Even in such a case, according to the first process of the present embodiment, step S121 is executed, and the delay information transmitted from the device other than the synchronization target device is discarded without being stored in the storage unit 22b, so that the synchronization of the process execution time is not affected.

[0074] <About the third treatment> As shown in Fig. 13, the third process of this embodiment differs from the third process of the first embodiment shown in Fig. 6 in that step S324 is provided instead of step S304. In step S324, delay information indicating the reception delay time calculated in step S303 is transmitted only to the synchronization target device.

[0075] As described above, the delay information transmission unit 41 of this embodiment is configured to transmit delay information only to synchronization target devices, which are devices designated in advance among other receiving devices. This configuration makes it possible to accommodate applications in which synchronization targets are limited, such as when it is sufficient to synchronize the execution times of processes only between specific receiving devices 40, or when it is desired to group receiving devices 40 whose execution times should be synchronized.

[0076] (Fourth embodiment) The fourth embodiment will be described below with reference to FIGS. As shown in FIG. 14, a receiving device 50 of this embodiment differs from the receiving device 20 of the first embodiment shown in FIG. 3 in that it includes a data receiving unit 52 instead of the data receiving unit 22.

[0077] When the data receiving unit 52 receives data transmitted from the transmitting device 10, it adds the received data to the end of the buffer 22a even if the reception delay time calculated by the delay information transmitting unit 21 is equal to or greater than the maximum delay time of other devices. In other words, when the data receiving unit 52 receives data transmitted from the transmitting device 10, it always adds the received data to the end of the buffer 22a, regardless of whether the reception delay time calculated by the delay information transmitting unit 21 is equal to or greater than the maximum delay time of other devices.

[0078] The receiving device 50 having the above configuration is configured to perform the first process, the second process, and the third process in parallel, similar to the receiving device 20 of the first embodiment, but the content of the first process is different from that of the first embodiment. The content of the first process performed by the receiving device 50 of this embodiment will be described below with reference to FIG. 15.

[0079] <Regarding the first treatment> As shown in Fig. 15, the first process of this embodiment differs from the first process of the first embodiment shown in Fig. 4 in that steps S103, S104, and S105 are omitted. In the first process of this embodiment, if step S101 returns "YES," that is, if the received data is input data, the process proceeds to step S106, where the currently received input data is added to the end of the queue.

[0080] As described above, when the data receiving unit 52 of this embodiment receives data transmitted from the transmitting device 10, the data receiving unit 52 always adds the received data to the end of the buffer 22a, regardless of whether the reception delay time calculated by the delay information transmitting unit 21 is equal to or greater than the maximum delay time of other devices. This configuration provides the following effects. That is, in the first process, if the reception delay time Ta of the data receiving unit 22 of the first embodiment is equal to or greater than the maximum delay time Tb of other devices, the data receiving unit 22 immediately uses the currently received input data without adding it to a queue.

[0081] In such a configuration, if data is already stored in the queue at that time and the reception delay time Tc of the data stored at the head of the queue is equal to or longer than the maximum delay time Tb of other devices, the data stored at the head of the queue will be retrieved and used in the second process at the same time as the input data used in the first process. In this case, the currently received input data and the previous data stored in the queue will be used in parallel, and the chronological order of the data will no longer be guaranteed.

[0082] This situation may occur when the reception delay time of the device itself changes from a state in which it is less than the maximum delay time of the other device to a state in which it is equal to or greater than the maximum delay time of the other device, for example, because the maximum delay time of the other device is significantly reduced for some reason. According to this embodiment, the input data received this time is not used as is without being added to the queue, and the data stored at the head of the queue is always used, so the problem of the chronological order of the data being used is not swapped.

[0083] (Other embodiments) The present invention is not limited to the embodiments described above and illustrated in the drawings, but can be modified, combined, or expanded as desired without departing from the spirit of the invention. The numerical values ​​and the like shown in the above embodiments are examples and are not limited to these. The present invention is not limited to the network 1 described in each of the above embodiments, but can be applied to any vehicular network in which a plurality of communication devices mounted on a vehicle are connected via communication lines.

[0084] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and equivalent modifications. In addition, various combinations and forms, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

[0085] The control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method described herein may be implemented by one or more special-purpose computers configured by combining a processor and memory programmed to perform one or more functions with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory tangible storage medium. [Explanation of symbols]

[0086] 1...network, 2...camera, 3...LiDAR, 4...preprocessing ECU, 5...sub-ECU, 6...control ECU, 7...control ECU, 8...communication line, 10...transmitting device, 11...data transmitting unit, 20...receiving device, 21...delay information transmitting unit, 22...data receiving unit, 30...receiving device, 31...delay information transmitting unit, 32...data receiving unit, 40...receiving device, 41...delay information transmitting unit, 50...receiving device, 52...data receiving unit.

Claims

1. In a vehicle network in which a plurality of communication devices (2 to 7) mounted on a vehicle are connected via a communication line (8), each of the plurality of communication devices is configured to be able to synchronize time with another; Among the plurality of communication devices, the communication devices that transmit specific data via the communication line are designated as transmitting devices (2, 3, 10), and the communication devices that receive and use the specific data via the communication line are designated as receiving devices (6, 7, 20, 30, 40, 50). the transmitting device includes a data transmitting unit (11) that transmits the specific data after adding transmission information indicating a transmission time that is a time when the specific data was acquired or a time when the specific data is to be transmitted; The receiving device a delay information transmitting unit (21, 31, 41) that calculates a reception delay time, which is the difference between the transmission time indicated by the transmission information added to the received specific data and the reception time, which is the time when the specific data is received, and transmits delay information indicating the calculated reception delay time to another receiving device that is another receiving device; a data receiving unit (22, 32, 52) for receiving and using the specific data transmitted from the transmitting device, the data receiving unit having a buffer (22a) with a queue structure capable of storing the specific data; Equipped with The data receiving unit When receiving the specific data transmitted from the transmitting device, if the reception delay time calculated by the delay information transmitting unit is less than a maximum other device delay time, which is the longest time among the reception delay times represented by the delay information received from the other receiving devices, the received specific data is added to the end of the buffer, and if the reception delay time calculated by the delay information transmitting unit is equal to or greater than the maximum other device delay time, the received specific data is used without being added to the buffer; A vehicle network that extracts and uses the specific data stored at the beginning of the buffer when the difference between the transmission time indicated by the transmission information assigned to the specific data stored at the beginning of the buffer and the current time becomes equal to or greater than the maximum delay time of the other device.

2. 2. The vehicle network according to claim 1, wherein the delay information transmission unit (21) periodically transmits the delay information at predetermined time intervals.

3. 2. The vehicle network according to claim 1, wherein the delay information transmission unit (31) transmits the delay information when it receives a change notification indicating that there has been a change in the configuration of at least one of the plurality of communication devices and the communication lines.

4. The vehicle network according to any one of claims 1 to 3, wherein the delay information transmitting unit (41) transmits the delay information representing the reception delay time only to a pre-designated device among the other receiving devices.

5. The vehicle network according to any one of claims 1 to 3, wherein the delay information transmission unit (21, 31) transmits delay information representing the reception delay time to all of the other receiving devices.

6. 4. The vehicle network according to claim 1, wherein when the data receiving unit (52) receives the specific data transmitted from the transmitting device, if the reception delay time calculated by the delay information transmitting unit is equal to or longer than the maximum delay time of the other device, instead of using the received specific data without adding it to the buffer, the data receiving unit (52) adds the received specific data to the end of the buffer.

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