JP7200812B2 - Communication systems, electronic devices and repeaters - Google Patents

Description

The present disclosure relates to communication systems, electronic devices and relay devices.

For example, Patent Literature 1 below describes an in-vehicle communication system configured such that communication frames exchanged between a plurality of ECUs mounted in a vehicle are relayed by a relay device. ECU is an abbreviation of "Electronic Control Unit".

In addition, the relay device described in Patent Document 1 detects the elapsed time since the communication frame was received for each communication frame, and prohibits the transfer of the communication frame whose elapsed time is longer than the allowable time. is configured as This configuration prevents the relay destination electronic device from receiving the communication frame with an excessive delay from the original reception timing.

JP-A-2008-160379

As a result of detailed studies by the inventors, the following problems were found.
For example, in an in-vehicle communication system, when an ECU as a communication terminal cannot transmit a communication frame due to an abnormality in a communication path or an abnormality in a communication interface provided in the ECU, the transmission of the communication frame is interrupted ( That is, the communication is interrupted). In the ECU, during a period in which communication is interrupted (hereinafter referred to as a communication interruption period), one or more communication frames waiting for transmission stay in a buffer for storing communication frames to be transmitted. become. After that, when the abnormality is resolved and the transmission is restarted, the communication frames retained in the buffer (that is, the retained frames) are sent from the ECU.

Therefore, the other ECU, which is the communication partner of the ECU, receives the communication frame at a timing delayed by the communication interruption period from the original reception timing. In this case, the data included in the received communication frame is data generated considerably before the reception timing of the communication frame. Therefore, there is a possibility that the processing using the data in the received communication frame may not be properly performed in the communication counterpart ECU. For example, when the communication partner ECU performs processing for judging the situation around the vehicle based on the data in the received communication frame, if the data in the received communication frame is excessively past data, the accuracy of the situation judgment is reduced. descend.

On the other hand, the relay device described in Patent Literature 1 is a technique for suppressing communication frames accumulated in the relay device from being transferred to the relay destination ECU. cannot solve the problem.

Therefore, in one aspect of the present disclosure, a communication frame that has been stuck in the transmission-side electronic device during a period from when the transmission-side electronic device is in a communication disruption state to when the transmission-side electronic device recovers is To provide a new technology that can prevent personal information from being acquired by others.

A communication system according to one aspect of the present disclosure comprises a plurality of electronic devices (11-13, 21-23) and at least one relay device (31, 32, 65). The relay device performs communication from a first electronic device, which is one of the plurality of electronic devices, to a second electronic device, which is a communication partner of at least one of the first electronic device among the plurality of electronic devices. configured to relay frames. The relay device includes a disruption determination unit (S110), a disruption notification unit (S130), a recovery determination unit (S310), and a recovery notification unit (S330). The second electronic device also includes a discard start section (S530) and a discard end section (S630, S640).

In the relay device, the disruption determination unit determines whether or not the first electronic device has entered a communication disruption state in which transmission of communication frames is interrupted. The disruption notifying unit, when the disruption determination unit determines that the first electronic device is in the communication disruption state, sends a communication disruption notification indicating that the first electronic device is in the communication disruption state to at least the first electronic device. 2 electronic device. The recovery determination unit determines whether or not the first electronic device has recovered from the communication disruption state to a normal state in which communication frames are transmitted. The recovery notifying unit, when the recovery determination unit determines that the first electronic device has recovered to the normal state, sends a communication recovery notification indicating that the first electronic device has recovered to the normal state to at least a second electronic device.

Then, in the second communication device, when the second electronic device receives the communication disruption notification, the discard initiation unit changes the operation mode of the second electronic device to Set the operation mode to discard communication frames. When the second electronic device receives the communication restoration notification, the discard termination unit determines whether a predetermined time has elapsed since the communication restoration notification was received, and determines whether the predetermined time has elapsed. When determined, the operation mode of the second electronic device is returned to the operation mode of acquiring communication frames from the first electronic device without discarding them.

According to such a configuration, when the first electronic device, which is the electronic device on the transmission side of the communication frame, is in a state of communication interruption, the second electronic device, which is the electronic device of the communication partner, receives the first electronic device. It becomes an operation mode that discards the communication frame of Then, when the first electronic device recovers from the communication interruption state to the normal state and the second electronic device receives the communication recovery notification from the relay device, a predetermined time elapses from the time when the communication recovery notification is received. After that, the second electronic device returns to an operation mode in which it acquires communication frames from the first electronic device without discarding them.

Therefore, the first electronic device returns from the communication-disconnected state to the normal state, transmits the communication frame (that is, the retained frame) that was retained during the communication-disconnected state, and the retained frame is transmitted for the predetermined time. The stuck frame is discarded even if it is received by the second electronic device before it has elapsed. Therefore, during the period from when the transmission-side electronic device is in a communication-disconnected state to when the transmission-side electronic device recovers, the communication frame that has been retained in the transmission-side electronic device may be acquired by the communication partner electronic device. Suppressed.

Further, as long as it is an electronic device that communicates with a communication partner device, which is an electronic device of a communication partner, via at least one relay device, and is provided with the discard start unit and the discard end unit, the electronic device of the present disclosure It can be used as a second electronic device in a communication system.

Further, a relay device for relaying a communication frame from a first electronic device to a second electronic device, the relay device comprising: the interruption determination unit; the interruption notification unit; Any relay device can be used as a relay device in the communication system of the present disclosure.

1 is a configuration diagram showing the configuration of a communication system according to a first embodiment; FIG. 4 is a flowchart showing first notification processing performed by an ECU as a relay device; 4 is a flowchart showing first notification forwarding processing performed by an ECU as a relay device; 4 is a flowchart showing second notification processing performed by an ECU as a relay device; 9 is a flowchart showing second notification forwarding processing performed by an ECU as a relay device; 4 is a flowchart showing first mode switching processing performed by an ECU as a communication terminal device; 4 is a flowchart showing second mode switching processing performed by an ECU as a communication terminal device; It is explanatory drawing explaining the example of an effect|action of 1st Embodiment. FIG. 2 is a configuration diagram showing the configuration of a communication system according to a second embodiment; FIG. It is explanatory drawing explaining the example of an effect|action of 2nd Embodiment.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.
[1. First Embodiment]
[1-1. Constitution]
A communication system 1 according to the first embodiment shown in FIG. 1 is, for example, a communication system mounted on a vehicle. The communication system 1 includes ECUs 11 to 13, 21 to 23, 31, 32 mounted on the vehicle.

The ECUs 11 to 13 and 21 to 23 correspond to terminal electronic devices (that is, communication terminal devices) in the communication system 1 . The ECUs 31 and 32 function as relay devices for relaying communication frames between the ECUs 11-13 and 21-23.

In this embodiment, the communication protocol is Ethernet. Ethernet is a registered trademark. Therefore, the communication frame is a frame based on the Ethernet standard (that is, an Ethernet frame). The ECUs 31 and 32 function as switches in Ethernet (that is, Ethernet switches). Hereinafter, the ECUs 31 and 32 are referred to as SW ECUs 31 and 32 in order to distinguish them from the ECUs 11 to 13 and 21 to 23 as communication terminal devices.

Each of ECUs 11-13 is connected to SW ECU 31 via communication lines 41-43, respectively. Each of ECUs 21-23 is connected to SW ECU 32 via communication lines 51-53, respectively. The SWECU 31 and the SWECU 32 are connected via a communication line 61 . Therefore, communication between any of the ECUs 11 to 13 and any of the ECUs 21 to 23 is performed via the SW ECUs 31 and 32 . Further, communications between the ECUs 11 to 13 are performed via the SW ECU 31 . Further, communication between the ECUs 21 to 23 is performed via the SW ECU 32 .

Note that the number of SWECUs as relay devices may be other than two. Further, the number of ECUs as communication terminal devices connected to each of the SW ECUs 31 and 32 may be other than three.

Each of the ECUs 11 to 13 and 21 to 23 includes a processing unit 2 that controls the operation of the ECU, and a communication interface (hereinafter referred to as communication I/F) 3 for transmitting and receiving communication frames. Note that FIG. 1 shows the processing unit 2 and the communication I/F 3 only for two ECUs 11 and 21 out of the ECUs 11 to 13 and 21 to 23 .

The processing unit 2 is composed of at least one microcomputer having a CPU 4 and a memory 5 . The operations of the ECUs 11 to 13 and 21 to 23, which will be described later, are realized by the processing unit 2, and more specifically, by the CPU 4 executing a program stored in the memory 5. FIG.

The SW ECUs 31 and 32 also include a processing unit 6 that controls the operation of the ECU, and a plurality of communication I/Fs 7 for transmitting and receiving communication frames. In FIG. 1, among the plurality of communication I/Fs 7 provided in the SWECU 31, a communication I/F 7 connected to the ECU 11 via a communication line 41 and a communication I/F 7 connected to the SWECU 32 via a communication line 61 are shown. Only two are shown, F7. Further, in FIG. 1 , among the plurality of communication I/Fs 7 provided in the SWECU 32 , a communication I/F 7 connected to the ECU 21 via the communication line 51 and a communication I/F 7 connected to the SWECU 31 via the communication line 61 . Only two are shown, F7.

The processing unit 6 is composed of at least one microcomputer having a CPU 7 and a memory 8 . The operations of the SW ECUs 31 and 32, which will be described later, are realized by the processing unit 6, and more specifically, by the CPU 7 executing a program stored in the memory 8. FIG.

The communication I/Fs 3 and 7 are circuits for transmitting and receiving communication frames, and correspond to PHYs (that is, physical layers) in Ethernet. In addition, the SWECUs 31 and 32 may be provided with switch hardware, separate from the processing unit 6, for performing switching processing (that is, relay processing) of communication frames. In this case, the operation of SW ECUs 31 and 32, which will be described later, may be realized by the hardware of the switch and the processing unit 6 operating in cooperation with each other. Moreover, the processing units 2 and 6 are not limited to microcomputers, and may be implemented by digital circuits, analog circuits, or a combination thereof.

[1-2. Processing performed by SW ECU]
Next, processing performed by the SW ECUs 31 and 32 will be described with reference to FIGS. 2 to 5. FIG. In the following description, when the SWECUs 31 and 32 are not particularly distinguished from each other, the SWECUs 31 and 32 are also referred to as "SWECU" by omitting the reference numerals. Similarly, when the ECUs 11 to 13 and 21 to 23 are not particularly distinguished from each other, the ECUs 11 to 13 and 21 to 23 are also referred to as "ECU" by omitting their reference numerals.

[1-2-1. First notification process]
The SWECU performs the first notification process shown in FIG. 2, for example, at regular time intervals.
As shown in FIG. 2, in the first notification process, the SW ECU determines in S110 whether or not each of the ECUs connected to the SW ECU (hereinafter referred to as connected ECUs) is in a state of communication disruption. . Here, "connected" means that it is connected without going through another SW ECU, in other words, it means that it is directly connected through a communication line. Further, the communication interruption state is a state in which the transmission of communication frames is interrupted.

For example, in S110, for each connected ECU, it is determined whether or not a communication frame (that is, a regular frame) that should be transmitted from the connected ECU at regular intervals is received within a specified determination time. If a frame is not received within the determination time, it may be determined that communication has been interrupted. In this case, the determination time may be set to a time longer than the predetermined time that is the transmission interval of the regular frames.

Further, for example, in S110, for each connected ECU, it is determined whether or not a predetermined abnormality has occurred in the communication I/F 7 for communicating with the connected ECU, causing the connected ECU to stop transmission. , it may be determined that the communication is interrupted when the abnormality occurs. The predetermined abnormality may be a so-called link down, for example, an output abnormality of the communication clock.

When the SW ECU determines in S110 that each of the connected ECUs is not in the communication-disconnected state, that is, there is no connected ECU in the communication-disconnected state, the SW ECU ends the first notification process.

Further, when the SW ECU determines in S110 that any one of the connected ECUs is in a state of communication interruption, the S ECU proceeds to S120.
In S120, SWECU creates a communication disruption notification. The communication loss notification according to the present embodiment is a notification indicating that any one of the ECUs is in a communication loss state and which ECU is in a communication loss state (hereinafter referred to as a communication loss ECU). Note that the notification referred to here is also a communication frame conforming to the communication protocol.

Therefore, identification information that can identify the communication disruption ECU is stored in a predetermined region in the communication disruption notification, for example, a data region (that is, a data region).
For example, the identification information that can identify the communication lost ECU may be the ID (that is, identification) of the communication lost ECU. In this case, the device that receives the communication loss notification can identify the communication loss ECU by the ID of the ECU included in the communication loss notification.

Further, for example, the SW ECU may include an ECU list in which a state flag indicating whether or not communication is interrupted is stored for each ECU existing in the communication system 1 . In this case, the ECU list may be stored in the communication loss notification data area as identification information that can identify the communication loss ECU. In this case, if the status flag corresponding to any ECU is set in the ECU list included in the communication loss notification, the device that has received the communication loss notification determines that the ECU corresponding to the set status flag is , is a communication disruption ECU.

Then, the SWECU advances from S120 to S130, and transmits the communication loss notification created in S120 to all the devices connected to the SWECU, other than the connected ECU determined to be in the communication loss state. . All devices here are connected ECUs and other SW ECUs. Note that the communication disruption notification may be transmitted to the connected ECU determined to be in the communication disruption state, but there is a high possibility that the communication disruption notification cannot be received by the connected ECU.

After completing the transmission of the communication disruption notification in S130, the SWECU ends the first notification process.
For example, when the ECU 21 connected to the SW ECU 32 is in a state of communication interruption, the communication interruption notification transmitted by the SW ECU 32 in S130 is a communication interruption notification indicating that the ECU 21 is in a communication interruption state.

[1-2-2. First notification forwarding process]
When a SW ECU receives a communication frame transmitted by another SW ECU, the SW ECU performs the first notification forwarding process shown in FIG.

As shown in FIG. 3, in the first notification transfer process, the SWECU determines in S210 whether or not the received communication frame (that is, the received frame) is the aforementioned communication disruption notification. That is, the SWECU determines in S210 whether or not a communication disruption notification has been received. If it is determined that the communication disruption notification has not been received, the first notification transfer process is ended, but if it is determined that the communication disruption notification has been received, the process proceeds to S220.

In S220, the SWECU transmits the received communication loss notification to all the devices connected to the SWECU, other than the SWECU that sent the communication loss notification, and then performs the first notification transfer process. exit. If two or more other SWECUs are connected to the SWECU, in S220, the communication loss notification may also be sent to the SWECUs other than the SWECU that sent the communication loss notification.

[1-2-3. Second notification process]
When it is determined by the first notification process in FIG. 2 that any one of the connected ECUs is in a state of communication disruption, the SW ECU performs the second notification process shown in FIG. 4, for example, at regular time intervals.

As shown in FIG. 4, in the second notification process, the SW ECU determines in S310 whether or not the connected ECU in the communication-disconnected state has returned to the normal state. The normal state is a state in which communication frames are transmitted.

For example, in S310, it is determined whether or not a communication frame has been received from a connected ECU that has been determined to be in a communication disruption state. It can be determined that the state has been restored.

Further, for example, in S310, it is determined whether or not the abnormality has been resolved for the connected ECU that has been determined to be in a state of communication interruption due to the occurrence of an abnormality in the communication I/F 7 described above, and if the abnormality has been resolved First, it may be determined that the normal state has been restored from the communication disruption state.

If the SW ECU determines in S310 that the connected ECU in the communication-disconnected state has not returned to the normal state, it terminates the second notification process.
Further, when the SW ECU determines in S310 that the connected ECU in the communication-disconnected state has returned to the normal state, the process proceeds to S320.

In S320, the SWECU creates a communication recovery notification. The communication recovery notification in the present embodiment is a notification indicating that the communication lost ECU has recovered to the normal state and the ECU that has recovered to the normal state (hereinafter referred to as communication recovery ECU).

Therefore, identification information that can specify the communication recovery ECU is stored in a predetermined area in the communication recovery notification, for example, a data area.
For example, the ID of the communication-recovery ECU may be used as the identification information that can identify the communication-recovery ECU. In this case, the device that has received the communication restoration notification can specify the communication restoration ECU by the ID of the ECU included in the communication restoration notification.

Further, for example, when the SW ECU has the aforementioned ECU list, the ECU list may be stored in the data area of the communication recovery notification as identification information that can specify the communication recovery ECU. In this case, if the status flag corresponding to the ECU determined to be in the communication cutoff state is reset in the ECU list included in the communication restoration notification, the device that has received the communication restoration notification is in the reset state. It can be specified that the ECU corresponding to the flag has returned to the normal state. The ECU that has been determined to be in a communication disruption state is the ECU corresponding to the set state flag in the ECU list included in the previously received communication disruption notification.

Then, the SWECU advances from S320 to S330, and transmits the communication disruption notification created in S320 to all the devices connected to the SWECU, other than the connected ECU determined to have returned to the normal state. . Note that the communication restoration notification may also be transmitted to the connected ECU determined to have returned to the normal state.

After completing the transmission of the communication recovery notification in S330, the SWECU ends the second notification process.
For example, when the ECU 21 connected to the SW ECU 32 recovers from the communication disruption state to the normal state, the communication recovery notification transmitted by the SW ECU 32 in S330 is a communication recovery notification indicating that the ECU 21 has recovered from the communication disruption state to the normal state. It turns out that.

[1-2-4. Second notification forwarding process]
The SWECU also performs the second notification forwarding process shown in FIG. 5 when receiving a communication frame transmitted by another SWECU.

As shown in FIG. 5, in the second notification transfer process, the SWECU determines in S410 whether or not the received frame is the above-described communication restoration notification. In other words, the SWECU determines in S410 whether or not a communication restoration notification has been received. If it is determined that the notification of communication restoration has not been received, the second notification transfer process is ended, but if it is determined that the notification of communication restoration has been received, the process proceeds to S420.

In S420, the SWECU transmits the received notification of communication restoration to the devices other than the SWECU that sent the communication restoration notification among all the devices connected to the SWECU, and then performs the second notification transfer process. exit. Note that if two or more other SWECUs are connected to the SWECU, in S420, the communication restoration notification may also be sent to the SWECUs other than the SWECU that sent the communication restoration notification.

On the other hand, although not shown, the SWECU performs communication frame switching processing in addition to the processing in FIGS. For example, based on the destination address (for example, the destination MAC address) in the received communication frame, the SWECU selects the communication I/F 7 (that is, the , destination port). Then, the received communication frame is transmitted from the communication I/F 7 determined as the transfer destination.

[1-3. Processing performed by the ECU]
Next, processing performed by the ECUs 11 to 13 and 21 to 23 will be described with reference to FIGS. 6 and 7. FIG.

[1-3-1. First Mode Switching Process]
The ECU performs the first mode switching process shown in FIG. 6 when receiving the communication frame from the SW ECU.

As shown in FIG. 6, in the first mode switching process, the SWECU determines in S510 whether or not the received frame is the above-described communication disruption notification. That is, in S510, the ECU determines whether or not a communication disruption notification has been received. If it is determined that the communication disruption notification has not been received, the first mode switching process is ended, but if it is determined that the communication disruption notification has been received, the process proceeds to S520.

In S520, the ECU determines whether or not the communication partner ECU (that is, the communication partner device) of the ECU is in a communication-disrupted state based on the received communication-disconnection notification. Specifically, based on the received notification of communication disruption, the ECU in the communication disruption state is specified, and it is determined whether or not the specified ECU is the communication partner ECU. The term "communication partner ECU" as used herein means an ECU that needs to receive a communication frame from that ECU and obtain and process data contained in the communication frame.

If the ECU determines in S520 that the communication partner ECU is not in the communication-disconnected state, the ECU terminates the first mode switching process, but determines that the communication partner ECU is in the communication-disrupted state. If so, proceed to S530.

Then, in S530, the ECU sets the operation mode of the ECU to an operation mode (hereinafter referred to as a discard mode) for discarding communication frames from the communication partner ECU in which communication is interrupted. End the mode switching process. Note that discarding a communication frame is, in detail, discarding the data included in the communication frame without acquiring it. Further, when communication is interrupted with a plurality of ECUs as communication partners, the operation mode for communication frames from the plurality of ECUs is set to the discard mode.

[1-3-2. Second mode switching process]
When the operation mode of the ECU is set to the discard mode in S530 of FIG. 6 with respect to the communication frame from at least one ECU of the communication partner and when the ECU receives the communication frame from the SW ECU, A second mode switching process shown in FIG. 7 is performed.

As shown in FIG. 7, in the second mode switching process, the SWECU determines in S610 whether or not the received frame is the above-described communication restoration notification. That is, in S610, the ECU determines whether or not a communication restoration notification has been received. If it is determined that the communication restoration notification has not been received, the second mode switching process is ended, but if it is determined that the communication restoration notification has been received, the process proceeds to S620.

In S620, the ECU determines whether or not the ECU with which the ECU communicates has returned to the normal state from the communication interruption state, based on the received communication restoration notification. Specifically, the communication recovery ECU is specified based on the received communication recovery notification, and it is determined whether or not the specified communication recovery ECU is the communication counterpart ECU.

If the ECU determines in S620 that the communication counterpart ECU has not returned to the normal state from the communication interruption state, the ECU terminates the second mode switching process, but the communication counterpart ECU terminates the communication interruption. If it is determined that the state has returned to the normal state, the process proceeds to S630.

In S630, the ECU determines whether or not a predetermined time T1 has elapsed since the ECU received the communication recovery notification. Then, in this S630, the process waits until a predetermined time T1 has passed since the communication recovery notification was received. The predetermined time T1 is set to a time longer than the maximum period of transmission of communication frames by the ECU of the communication partner determined to have returned to the normal state from the communication disruption state.

When the ECU determines in S630 that the predetermined time T1 has elapsed, the process proceeds to S640.
In S640, the ECU sets the operation mode of the ECU from the discard mode to the normal mode with respect to the communication frame from the communication partner ECU determined to have returned to the normal state from the communication disruption state. The normal mode is an operation mode that is not a discard mode, and is an operation mode that acquires communication frames from the communication counterpart ECU without discarding them. Acquiring a communication frame means, in other words, acquiring data included in the communication frame and using it for a predetermined process. After performing the process of S640, the ECU ends the second mode switching process.

[1-4. Action example]
2 to 5 by the SW ECU and the processes of FIGS. 6 and 7 by the ECU will be described with reference to FIG. Incidentally, in the operation example shown in FIG. 8 , at least the ECU 21 is the communication partner of the ECU 11 . Further, in the following description using FIG. 8, the step numbers written in parentheses are the step numbers of the process for realizing the corresponding operation among the step numbers in FIGS.

At time t1 in FIG. 8, it is assumed that the communication of the ECU 21 is interrupted.
Then, the SW ECU 32 to which the ECU 21 is connected determines at time t2 that the ECU 21 is in a state of communication interruption <S110>. Then, at time t3, the SWEC 32 transmits a communication interruption notification indicating that the ECU 21 is in a communication interruption state to all the apparatuses connected to the SWEC 32 other than the ECU 21 <S130>. Further, the other SWECU 31 receives the communication loss notification from the SWEC 32 at time t4, and transmits the received communication loss notification to devices other than the SWEC 32 among all the devices connected to the SWEC 31. <S220>. Therefore, the SW ECU 32 sends a communication interruption notification indicating that the ECU 21 is in a communication interruption state to the ECU 11 with which the ECU 21 communicates via the SW ECU 31 .

At time t5, the ECU 11 receives the communication interruption notification sent from the SW ECU 32 via the SW ECU 31, and based on this communication interruption notification, determines that the ECU 21, which is the communication partner of the ECU 11, is in the communication interruption state. <S520>. Therefore, the ECU 11 sets the operation mode of the ECU 11 to a discard mode for discarding the communication frame from the ECU 21 <S530>.

After that, at time t6, it is assumed that the abnormality that caused the communication interruption state of the ECU 21 is resolved and the ECU 21 returns to the normal state.
Then, at time t7, the SW ECU 32 determines that the ECU 21 has recovered from the communication interruption state to the normal state <S310>. Then, at time t8, the SWEC 32 transmits a communication recovery notification indicating that the ECU 21 has recovered from the communication-disconnected state to the normal state to devices other than the ECU 21 among all the devices connected to the SWEC 32 <S330 >. At time t9, the other SWECU 31 receives the communication recovery notification from the SWEC 32, and transmits the received communication recovery notification to all the devices connected to the SWEC 31 other than the SWEC 32. <S420>. Therefore, the SW ECU 32 sends a communication recovery notification indicating that the ECU 21 has returned to the normal state to the ECU 11 with which the ECU 21 communicates via the SW ECU 31 .

At time t10, the ECU 11 receives the communication recovery notification sent from the SW ECU 32 via the SW ECU 31, and based on this communication recovery, determines that the ECU 21 has recovered from the communication interruption state to the normal state <S620>. . Then, the ECU 21 determines whether or not a predetermined time T1 has passed since the communication recovery notification was received <S630>. is returned to the normal mode in which the communication frame is acquired without being discarded <S640>.

Therefore, when the ECU 11 receives a communication frame whose transmission source is the ECU 21 after time t11, the ECU 11 acquires data included in the communication frame and uses the data for predetermined control processing. The predetermined control process is a process assigned to the ECU 11 in the communication system 1 . This control process may be, for example, a process for judging the surrounding conditions of the vehicle.

In FIG. 8, the period during which the operation mode of the ECU 11 is the discard mode is described as "reception filter period". The reception filter in the example of FIG. 8 means that the frame from the ECU 21 is selected and discarded.

On the other hand, in the ECU 21, one or more communication frames waiting for transmission stay in a buffer for storing communication frames to be transmitted (i.e., a transmission buffer) while the ECU 21 is in a state of communication interruption. do. Then, at time t6, when the normal state is restored, the ECU 21 starts transmitting the communication frames that were retained in the buffer during the period of the communication interruption state (that is, retained frames). Further, the transmission of the staying frame in the buffer is completed before the next transmission timing in the ECU 21 arrives. In other words, the length of the period during which the staying frame is transmitted is shorter than the maximum period during which the ECU 21 transmits the communication frame. The predetermined time T1 is set to a time longer than the maximum cycle in which the ECU 21 transmits communication frames. Therefore, the transmission of the staying frame from the ECU 21 ends before the predetermined time T1 elapses after the ECU 11 receives the communication recovery notification.

Therefore, the accumulated frame transmitted by the ECU 21 is transferred to the ECU 11 via the SWECU 32 and the SWECU 31, but the accumulated frame is received by the ECU 11 only during the period in which the ECU 11 is in the discard mode (that is, the reception during the filter period). Therefore, in the ECU 11, the retained frame from the ECU 21 is discarded without being used for control processing.

Further, in FIG. 8, among the communication frames transmitted from the ECU 21, those described as "normal frames" are communication frames transmitted after the transmission of all the residual frames is completed. This is a communication frame containing new data generated after the cancellation. Then, this normal frame is transferred to the ECU 11 via the SWECU 32 and the SWECU 31, and is acquired by the ECU 11 without being discarded. That is, normal frames are used for control processing in the ECU 11 .

In the example of FIG. 8, the ECU 21 corresponds to the first electronic device, and the ECU 11 corresponds to the second electronic device. In the present embodiment, among the processes performed by the SWECU, S110 in FIG. 2 corresponds to the process of the disruption determination section, S130 in FIG. 2 corresponds to the process of the disruption notification section, and S310 in FIG. corresponds to the processing of the restoration determination unit, and S330 in FIG. 4 corresponds to the processing of the restoration notification unit. Among the processes performed by the ECU, S530 of FIG. 6 corresponds to the process of the discard start section, and S630 and S640 of FIG. 7 correspond to the processes of the discard end section.

[1-5. effect]
According to 1st Embodiment detailed above, there exist the following effects.
(1a)
The SW ECU determines whether or not any of the connected ECUs has lost communication. Then, when it is determined that any of the connected ECUs is in a communication-broken state, a communication-broken-up notification indicating the communication-broken-up ECU is sent to at least the communication of the communication-broken-up ECU via the other SW ECU or not via the other SW ECU. Send to the partner ECU. After that, the SW ECU determines whether or not the communication-disrupted ECU among the connected ECUs has returned to a normal state. Then, when it is determined that the communication-disrupted ECU has returned to a normal state, it transmits a communication-recovery notification indicating the communication-recovery ECU to at least the ECU of the communication partner, via the other SW ECU or not via the other SW ECU. .

On the other hand, when the ECU receives the communication loss notification, the ECU determines based on the communication loss notification whether or not the communication partner ECU of the ECU is in the communication loss state. Then, when it is determined that the ECU of the communication partner is in the communication-disconnected state, a discard mode for discarding the communication frame from the communication-disconnected ECU is set. Further, when the ECU receives a communication restoration notification while in the discard mode, the ECU determines whether or not the ECU with which the ECU communicates has returned to the normal state from the communication interruption state based on the communication restoration notification. judge. Then, when it is determined that the ECU of the communication partner has returned to the normal state, the discard mode changes to the normal mode, that is, the communication is interrupted at the timing when the predetermined time T1 has elapsed from the time when the communication return notification is received. It returns to the operation mode which acquires the communication frame from ECU, without discarding it.

Here, for example, among the ECUs 11 to 13 and 21 to 23, the ECU 21 is the first electronic device, and the ECU 11 with which the ECU 21 communicates is the second electronic device.
In this example, the SWECU 32 determines in S110 of FIG. 2 whether or not at least the first electronic device is in a communication disruption state. Then, when the SW ECU 32 determines that the first electronic device is in the communication-disrupted state, in S130 of FIG. Send to a second electronic device. After that, in S310 of FIG. 4, the SW ECU 32 determines whether or not the first electronic device has recovered from the communication interruption state to the normal state. Then, when the SWECU 32 determines that the first electronic device has returned to the normal state, in S330 of FIG. 2 electronic device. On the other hand, when the second electronic device receives the communication disruption notification indicating that the first electronic device is in the communication disruption state, the second electronic device changes the operation mode of the electronic device to the communication frame from the first electronic device. set to discard mode. After that, when the second electronic device receives a communication recovery notification indicating that the first electronic device has returned to the normal state, whether or not a predetermined time T1 has passed since the communication recovery notification was received. judge. Then, when it is determined that the predetermined time T1 has passed, the operation mode of the electronic device is returned to the normal mode in which communication frames from the first electronic device are acquired without being discarded.

According to such a configuration, the first electronic device recovers from the communication disruption state to the normal state, transmits the communication frame (that is, the retention frame) retained during the communication disruption state, and transmits the retention frame. is received by the second electronic device before the predetermined time T1 elapses, the stuck frame is discarded. Therefore, it is possible to prevent the electronic device of the communication partner from acquiring a retained frame containing data generated at an old time.

Further, the predetermined time T1 is set to a time longer than the maximum cycle in which the communication partner ECU (that is, the first electronic device) that has returned to the normal state from the communication interruption state transmits the communication frame. Therefore, it is easy for the second electronic device to return from the discard mode to the normal mode after the first electronic device that has returned to the normal state from the communication disruption state completes transmission of the retained frame.

A comparative example will now be described.
For example, if a communication frame contains a time stamp indicating the generation time of the communication frame, the ECU on the receiving side can, from the time stamp in the received frame and the current time ascertained by the ECU, It is believed that the newness of the received frame can be determined. However, in this case, it is necessary to synchronize the times grasped by each ECU. Therefore, each ECU needs to perform communication and processing for time synchronization. On the other hand, according to the communication system 1 of this embodiment, communication and processing for time synchronization can be made unnecessary.

(1b)
Furthermore, in the communication system 1 of the present embodiment, when a communication loss notification transmitted by another SWECU is received by the SWECU, the SWECU transmits the communication loss notification to at least one connected to the SWECU. configured to transmit to the device. Further, the SWECU is configured to, when receiving a communication restoration notification transmitted by another SWECU, transmit the communication restoration notification to at least one device connected to the SWECU. ing. Therefore, even if there are a plurality of SW ECUs between the transmitting ECU and the receiving ECU, the SW ECU to which the transmitting ECU is connected sends the communication interruption notification and the communication restoration to the receiving ECU. Notifications and can be forwarded.

In this embodiment, among the processes performed by the SWECU, S220 in FIG. 3 corresponds to the process as the first transfer unit, and S420 in FIG. 5 corresponds to the process as the second transfer unit.
[2. Second Embodiment]
[2-1. Differences from First Embodiment]
Since the basic configuration of the second embodiment is the same as that of the first embodiment, differences will be described below. Note that the same reference numerals as in the first embodiment indicate the same configurations, and refer to the preceding description.

The communication system 10 of the second embodiment shown in FIG. 9 differs from the communication system 1 of the first embodiment in the following items <1> to <3>.
<1> ECUs 11 to 13 are connected to a common communication line 63 . The ECUs 21-23 are also connected to a common communication line 64. FIG. The communication protocol is not Ethernet but CAN (that is, Controller Area Network), for example. CAN is a registered trademark.

<2> Instead of the SWECUs 31 and 32, an ECU 65 is provided as a relay device.
The ECU 65 is connected to both communication lines 63 and 64 . Then, the ECU 65 relays communication frames (that is, CAN frames) exchanged between any of the ECUs 11-13 and any of the ECUs 21-23. That is, the ECU 65 is an ECU that functions as a gateway that connects the network of the communication line 63 system and the network of the communication line 64 system. Therefore, the ECU 65 is hereinafter referred to as the GW ECU 65 . GW is an abbreviation for gateway.

<3> The GW ECU 65 performs the processes of FIGS. 2 and 4, but does not perform the processes of FIGS.
[2-2. Action example]
FIG. 10 shows an example of the effect of the GW ECU 65 performing the processes of FIGS. 2 and 4 and the ECU performing the processes of FIGS.

Similarly to FIG. 8, FIG. 10 also shows a case where the ECU 21 is in a communication-disconnected state and a communication-disconnection notification is sent to the ECU 11 with which the ECU 21 communicates. As shown in FIG. 10, the GWECU 65 plays the same role as the SWECU 32 in the operation example of FIG. In the operation example of FIG. 10, the GW ECU 65 relays to the ECU 11 a communication interruption notification indicating that the ECU 21 has entered a communication interruption state and a communication restoration notification indicating that the ECU 21 has returned to its normal state. It will be sent without going through the device. Therefore, in FIG. 10, the operation contents at times t4 and t9 in FIG. 8 are deleted.

[2-3. effect]
According to the second embodiment as well, the same effect as the effect described in (1a) above for the first embodiment can be obtained.

[3. Other embodiments]
Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications can be made.

For example, in the first embodiment, the communication interruption notification and the communication restoration notification from the SW ECU may be sent to the ECU that is the communication partner of the ECU in the communication interruption state. For example, in the operation example of FIG. 8 described in the first embodiment, the SWECU 32 transmits the communication loss notification and the communication recovery notification to the ECU 11, which is the communication partner of the ECU 21, among all the devices connected to the SWECU 32. It may be transmitted only to the SWECU 31 that is set. Then, the SWECU 31 may transmit the communication interruption notification and the communication restoration notification from the SWECU 32 to only the ECU 11 among all the devices connected to the SWECU 31 .

In addition, in the process of FIG. 3, the SWECU stores the contents of the communication interruption notification received from the other SWECU, and until the communication restoration notification is received, for example, at regular time intervals, the communication interruption of the stored contents is stored. Notification may be sent. By configuring in this way, the possibility of the communication disruption notification reaching the target ECU increases.

Also, the ECUs 11-13, 21-23, SW ECUs 31, 32, GW ECU 65 and techniques described in the present disclosure may be implemented by a processor and memory programmed to perform one or more functions embodied by a computer program. may be implemented by a dedicated computer provided by configuring Alternatively, the ECUs 11-13, 21-23, SW ECUs 31, 32, GW ECU 65 and techniques described in this disclosure are implemented by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. may Alternatively, the ECUs 11-13, 21-23, SW ECUs 31, 32, GW ECU 65 and techniques described in this disclosure can be implemented using a processor and memory programmed to perform one or more functions and one or more hardware It may also be implemented by one or more dedicated computers configured in combination with a processor configured by logic circuits. Computer programs may also be stored as computer-executable instructions on a computer-readable non-transitional tangible storage medium. The method of realizing the function of each part included in the ECUs 11 to 13, 21 to 23, the SW ECUs 31, 32, and the GW ECU 65 does not necessarily include software. may be implemented using

Also, a plurality of functions possessed by one component in the above embodiment may be realized by a plurality of components, or a function possessed by one component may be realized by a plurality of components. Also, a plurality of functions possessed by a plurality of components may be realized by a single component, or a function realized by a plurality of components may be realized by a single component. Also, part of the configuration of the above embodiment may be omitted. Moreover, at least part of the configuration of the above embodiment may be added or replaced with respect to the configuration of the other above embodiment.

In addition, a program for causing a computer to function as each of the ECUs 11 to 13, 21 to 23, the SW ECUs 31, 32, and the GW ECU 65 described above, a non-transitional actual recording medium such as a semiconductor memory in which the program is recorded, a communication control method, etc. The present disclosure can also be implemented in various forms.

1, 10... communication system, 11 to 13, 21 to 23... ECU, 31, 32... SW ECU, 65... GW ECU

Claims (5)

a plurality of electronic devices (11-13, 21-23);
A communication frame from a first electronic device that is one of the plurality of electronic devices to a second electronic device that is a communication partner of at least one of the first electronic device among the plurality of electronic devices. at least one relay device (31, 32, 65) configured to relay the
The relay device
a disruption determination unit (S110) configured to determine whether or not the first electronic device is in a communication disruption state in which transmission of the communication frame is interrupted;
When the disruption determination unit determines that the first electronic device is in the communication disruption state, at least the communication disruption notification indicating that the first electronic device is in the communication disruption state. a disruption notification unit (S130) configured to send to the second electronic device;
a recovery determination unit (S310) configured to determine whether the first electronic device has recovered from the communication disruption state to a normal state in which the communication frame is transmitted;
When the recovery determination unit determines that the first electronic device has recovered to the normal state, a communication recovery notification indicating that the first electronic device has recovered to the normal state is sent to at least the first electronic device. a return notification unit (S330) configured to send to the electronic device of No. 2,
The second electronic device is
The second electronic device is configured to change an operation mode of the second electronic device to an operation mode of discarding communication frames from the first electronic device when the communication disruption notification is received by the second electronic device. a discard start unit (S530);
When the second electronic device receives the communication restoration notification, it is determined whether a predetermined time has passed since the communication restoration notification was received, and if it is determined that the predetermined time has passed, the a discard termination unit (S630, S640) configured to return an operation mode of a second electronic device to an operation mode of acquiring communication frames from the first electronic device without discarding them;
Communications system. A communication system according to claim 1,
The predetermined time is a time longer than the maximum cycle in which the first electronic device transmits the communication frame,
Communications system. An electronic device configured to communicate with a communication partner device, which is a communication partner electronic device, via at least one relay device,
Among the notifications transmitted from the at least one relay device, the electronic device receives a communication disruption notification indicating that the communication partner device has entered a communication disruption state in which transmission of communication frames is interrupted. a discard initiation unit (S530) configured to set the operation mode of the electronic device to an operation mode for discarding communication frames from the communication partner device when the
Among the notifications transmitted from the at least one relay device, the electronic device receives a communication recovery notification indicating that the communication partner device has recovered from the communication disruption state to a normal state in which the communication frame is transmitted. if a predetermined period of time has passed since the communication recovery notification was received, and if it is determined that the predetermined period of time has passed, the operation mode of the electronic device is changed to the operation mode of the communication partner device. a discard termination unit (S630, S640) configured to return to an operation mode of acquiring communication frames without discarding them;
electronic device. The electronic device according to claim 3,
The predetermined time is a time longer than the maximum cycle in which the communication partner device transmits the communication frame.
electronic device. From a first electronic device that is any one of a plurality of electronic devices (11 to 13, 21 to 23), a second electronic device that is a communication partner of at least one of the plurality of electronic devices (11 to 13, 21 to 23) a relay device configured to relay communication frames to an electronic device of
a disruption determination unit (S110) configured to determine whether or not the first electronic device is in a communication disruption state in which transmission of the communication frame is interrupted;
When the disruption determination unit determines that the first electronic device is in the communication disruption state, at least the communication disruption notification indicating that the first electronic device is in the communication disruption state. a disruption notification unit (S130) configured to send to the second electronic device;
a recovery determination unit (S310) configured to determine whether the first electronic device has recovered from the communication disruption state to a normal state in which the communication frame is transmitted;
When the recovery determination unit determines that the first electronic device has recovered to the normal state, a communication recovery notification indicating that the first electronic device has recovered to the normal state is sent to at least the first electronic device. a return notification unit (S330) configured to send to the electronic device of No. 2 ,
When the communication disruption notification transmitted by the communication disruption notification unit provided in another relay device is received by the relay device, the received communication disruption notification is sent to at least one device connected to the relay device. a first forwarding unit (S220) configured to transmit to a device;
When the communication recovery notification transmitted by the recovery notification unit provided in another relay device is received by the relay device, the received communication recovery notification is sent to at least one device connected to the relay device. a second forwarding unit (S420) configured to transmit to the device;
Relay device.

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