JP2008227591A - On-vehicle relay connection unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To continue the transmission of a message to a communication line even when communication abnormality occurs in message transmission to one communication line of a specified electronic control unit connected with two communication lines. <P>SOLUTION: The relay connection unit 20 of an on-vehicle communication system 10 comprises: a reception part 21 connected through first and second communication lines to a specified ECU 30 which is connected to both of the first and second communication lines B and directly transmits and receives a specified message M, for receiving the specified message M transmitted by the specified ECU; first and second reception counters 25B for recording the number and reception cycle of the specified messages M received in the reception part to be transmitted to the first and second communication lines; and a processing part 23 for comparing the number of the specified messages or the like recorded in the first and second reception counters with a judgement value, and in the case of detecting the occurrence of abnormality in the transmission of the specified message from the specified ECU to the first or second communication line, for relaying the specified message M received from one communication line to the other communication line not receiving it. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an in-vehicle relay connection unit, and more specifically, in the relay connection unit that is connected between a first communication line and a second communication line and relays transmission / reception of messages between electronic control units. A specific electronic control unit having a high degree of importance that is connected to both the first and second communication lines and directly transmits and receives a message without relaying the relay connection unit. Even if a communication error occurs in a transmission message, the relay connection unit can continue communication.

In recent years, the number of electrical components and electrical devices mounted on a vehicle has increased rapidly as the functions and performance of the vehicle have increased, and the wiring in the vehicle has become more complex and larger.
Therefore, in order to suppress the increase in the number of wires in the vehicle, ECUs that control in-vehicle electrical components are divided into groups such as body systems for seats and doors, power train systems such as engines and throttles, and the like. In-vehicle use that connects ECUs belonging to 1 through communication lines, and has a relay connection unit (gateway unit) interposed between communication lines connected to different ECUs, and relays communication between ECUs in the group by the relay connection unit A communication system is employed.
In this way, a large number of ECUs mounted on the vehicle are grouped, and in each group, a communication line connected to the ECU is connected to the relay connection unit, thereby reducing the number of wires, The communication speed between the ECUs via the relay connection unit is increased.

  In the above-described in-vehicle communication system, if any of the plurality of ECUs existing on the communication line fails and communication abnormality occurs, control of the vehicle and electrical components is hindered. Therefore, it is preferable to quickly identify the ECU that is causing the communication abnormality and to quickly deal with the communication abnormality.

In view of this, Japanese Patent Laid-Open No. 2006-287739 (Patent Document 1) proposes a relay connection unit that determines communication abnormality of the ECU.
The relay connection unit includes a reception counter that counts the number of received messages, and compares the number of receptions of a message within a predetermined period with a determination value that is the number of messages that the relay connection unit should receive. Thus, a communication abnormality is detected such that the message is not transmitted from the ECU or the message transmission cycle is abnormal.
When a message communication abnormality is detected, the relay connection unit suppresses transmission by the ECU that has transmitted the abnormal message.

On the other hand, in an in-vehicle communication system in which a relay connection unit is interposed between the first communication line and the second communication line to which the electronic control unit is connected, the electronic control is performed because the importance is high and the number of message transmissions is large. When a message needs to be transmitted simultaneously from the unit to the dual communication line of the first communication line and the second communication line, and when there are many messages to be transmitted to the first communication line and the second communication line The electronic control unit may be connected to both the first communication line and the second communication line.
Hereinafter, the electronic control unit that simultaneously transmits a message to the first and second communication lines of the dual system is referred to as a specific electronic control unit.
By connecting the specific electronic control unit directly to the first communication line and the second communication line, the specific electronic control unit transmits the same message to both the first communication line and the second communication line without going through the relay connection unit. Therefore, the relay connection unit does not need to perform relay processing of the message (specific message) transmitted by the specific electronic control unit, and the relay processing of the relay connection unit does not increase. Further, since the specific message is transmitted without relaying through the relay connection unit, the communication speed of the specific message can be increased.

When the relay connection unit of Patent Document 1 is used in the in-vehicle communication system to which the specific electronic control unit is connected as described above, the relay connection unit does not perform the relay process of the specific message transmitted by the specific electronic control unit. Since the first communication line and the second communication line to which the message is transmitted are connected, the specific message can be received.
For this reason, the relay connection unit includes a reception counter that counts the number of receptions of the specific message, and the communication abnormality of the specific electronic control unit can be detected by comparing the number of receptions of the specific message with the determination value.

JP 2006-287739 A

  However, when the specific electronic control unit connected to both the first communication line and the second communication line is transmitting the same specific message to both communication lines as described above, for example, communication to the specific electronic control unit is performed. When an abnormality occurs and a specific message cannot be transmitted to the first communication line, the relay connection unit of Patent Document 1 does not perform relay processing even if a communication abnormality is detected from the received specific message. For this reason, there is a problem that the specific message received from the second communication line cannot be relayed to the first communication line, and the specific message is not transmitted to the first communication line.

  The present invention has been made in view of the above problem, and can maintain communication even if a communication abnormality occurs in message transmission of a specific electronic control unit connected to the first and second communication lines of the dual system. The problem is to have the relay connection unit.

In order to solve the above problems, the present invention provides:
A relay connection unit that connects between a first communication line and a second communication line to which an electronic control unit is connected, respectively, and relays message transmission / reception between the electronic control units connected to the first and second communication lines. And
Connected to the specific electronic control unit that is connected to both the first and second communication lines and directly transmits and receives messages, and is connected via the first and second communication lines to receive messages transmitted by the specific electronic control unit. A receiving unit to
A first reception counter that records the number or / and the reception cycle of the message transmitted from the specific electronic control unit received by the reception unit to the first communication line;
A second reception counter that records the number or / and the reception cycle of the message transmitted from the specific electronic control unit received by the reception unit to the second communication line;
Abnormality in message transmission from the specific electronic control unit to the first communication line or the second communication line by comparing the number of messages and / or the period recorded in the first reception counter and the second reception counter with a determination value A processing unit that relays to the other communication line that has not received the message of the specific electronic control unit received from one communication line,
The relay connection unit is provided.

According to the said structure, a relay connection unit receives the message which a specific electronic control unit transmits to a 1st communication line and a 2nd communication line, and the number or / and period of a message are a 1st reception counter and a 2nd reception counter. Since it is recorded, it is possible to detect whether or not a communication abnormality has occurred in transmission of a message to the first communication line or the second communication line of the specific electronic control unit using the number of messages or / and the period. it can.
Further, when the specific electronic control unit transmits the same message to the first communication line and the second communication line, for example, the relay connection unit cannot receive the message transmitted by the specific electronic control unit to the first communication line. When the communication abnormality of the specific electronic control unit is detected, the relay connection unit relays the message received from the second communication line to the first communication line instead of the specific electronic control unit.
For this reason, even if a communication error occurs in the message transmission to the other communication line of the specific electronic control unit, by transmitting the message received from one communication line to the other communication line, It is possible to reliably continue sending the message.

The specific electronic control unit is an important electronic control unit for controlling a traveling system device. When a large number of sensors are connected to the first communication line and the second communication line and the number of times of message transmission is large, message data When the length is long, the relay connection unit of the present invention is preferably used.
The specific electronic control unit is, for example, an electronic control unit related to engine control of a hybrid vehicle.
The relay connection unit according to the present invention ensures that the important message received from one communication line is transmitted to the other communication line even when an abnormality occurs in the transmission of the important message to the other communication line of the specific electronic control unit. Therefore, the electronic control unit connected to the other communication line and requiring the important message can reliably receive the important message.
When the specific electronic control unit normally transmits a message, the specific electronic control unit directly transmits a message to the first communication line and the second communication line, and the relay connection unit does not relay the message. Even when the number of messages transmitted by the specific electronic control unit is large or when the data length of the message is long, the relay processing of the relay connection unit does not increase.

The relay connection unit of the present invention includes a storage unit including a routing map indicating a relationship between a message to be received and a relay destination,
When the processing unit detects that a message is not transmitted from the specific electronic control unit to the first communication line or the second communication line, the routing unit routes the relay destination communication line of the message of the specific electronic control unit. It is preferable to instruct the storage unit to rewrite the map.

The message relayed by the relay connection unit and the relay destination communication line are all recorded in the routing map, and the processing unit relays the message according to the routing map.
For this reason, when the relay connection unit detects a communication abnormality of the specific electronic control unit, the relay connection unit replaces the specific electronic control unit by rewriting the relay destination communication line of the message of the specific electronic control unit to the routing map. The message of the specific electronic control unit received from one communication line can be relayed to the other communication line that has not been received.

Preferably, the processing unit changes an ID dedicated for receiving the message of the specific electronic control unit received from the one communication line to a relay ID when relaying to the other communication line.
The specific electronic control unit transmits the same message having the same ID to the first communication line and the second communication line, and the relay connection unit changes the ID of the message of the specific electronic control unit received from one communication line. Thus, a message having an ID different from the message directly transmitted by the specific electronic control unit can be transmitted to the other communication line.
The electronic control unit connected to the other communication line and receiving the message transmitted from the specific electronic control unit records the ID of the message dedicated for reception and the relay ID in advance, and the specific electronic control unit directly transmits the message. Messages received through the relay connection unit can be discriminated and received.

In particular, if the specific electronic control unit is sending a message to the other communication line at irregular or abnormal intervals and communication is abnormal, the periodic abnormality message transmitted from the specific electronic control unit to the other communication line Then, both normal messages in which the relay connection unit relays the message received from one communication line to the other communication line are transmitted.
When the electronic control unit connected to the other communication line receives both ID messages, it receives only the relay ID message and uses it to control electronic devices connected to the electronic control unit. To do.
In this way, when the relay connection unit relays a message to the relay transmission destination communication line, the electronic control unit connected to the communication line to which the message has been transmitted is changed to the relay connection by changing the message ID. It is possible to discriminate and use a message that does not have a cycle abnormality via the unit, and to prevent reception of a message having the same content.

The processing unit compares the number of messages and / or the reception period stored in the first reception counter and the second reception counter with a determination value, and from a state in which no message is transmitted from the specific electronic control unit. When it is detected that the transmission has been returned, it is preferable to instruct the storage unit to rewrite the relay transmission destination of the message of the specific electronic control unit from the routing map.
When the specific electronic control unit returns from the communication abnormal state to the normal communication state, the relay connection unit rewrites the routing map, and the message of the specific electronic control unit received from one communication line is changed to the message. It is possible to stop relaying to the other communication line that has not received.

  As described above, according to the relay connection unit of the present invention, in the relay connection unit that is connected between the first communication line and the second communication line and relays transmission and reception of messages between the electronic control units, In the case of including a specific electronic control unit that is connected to both the first and second communication lines and directly transmits and receives a message without relaying the relay connection unit, the relay connection unit has the specific electronic control unit as the first electronic control unit. And the message to be transmitted to the second communication line is received, and the number or / and period of the message is recorded by the first reception counter and the second reception counter, so that the specific electronic control is performed using the number or / and period of the message. It is possible to detect whether or not a communication abnormality has occurred in the transmission of a message to the first communication line or the second communication line of the unit.

  In addition, the specific electronic control unit transmits the same message to the first communication line and the second communication line, and the relay connection unit cannot normally receive the message from the other communication line, and the communication error of the specific electronic control unit is detected. If detected, the relay connection unit relays the message of the specific electronic control unit received from one communication line to the other communication line instead of the specific electronic control unit, and therefore transmits the message to the other communication line. Can continue reliably.

Embodiments of the present invention will be described with reference to the drawings.
1 to 5 show a first embodiment of the present invention.
FIG. 1 shows an in-vehicle communication system 10 provided with a relay connection unit 20 of the present invention. The relay connection unit 20 (gateway unit) is connected between the first communication line 11A and the second communication line 11B, and the first communication line 11A has electronic control units (ECUs) 12A-1, 12A-2, ECUs 12B-1 and 12B-2 are connected to the two communication lines 11B, respectively.
Further, the specific ECU 30 is connected to both the first communication line 11A and the second communication line 11B, and the specific ECU 30 transmits and receives the specific messages MA and MB having the same ID and message content. It goes directly to the communication line 11B.
The communication protocol of the in-vehicle communication system 10 of the present embodiment uses the CAN protocol, the access method is CSMA / CA, and the maximum communication speed is 1 Mbps.

When the relay connection unit 20 detects that an abnormality has occurred in the transmission of the specific message M from the specific ECU 30 to one of the communication lines, the relay connection unit 20 receives the specific message M from the other communication line 11 and determines the ID of the specific message M. The relay specific message MC is rewritten, the routing map RM of the relay connection unit 20 is rewritten, and the relay specific message MC is relayed to one communication line 11 that cannot receive the specific message M from the specific ECU 30.
The relay connection unit 20 relays transmission / reception of the ECU message m between the ECUs 12 belonging to different communication lines 11.

  As shown in FIG. 2, the frame of the specific message M and ECU message m transmitted and received by the in-vehicle communication system 10 includes an ID unit 13 and a data unit 14, and the ID unit 13 includes the specific message M or ECU message. A reception-specific ID is assigned by the specific ECU 30 or ECU 12 that transmits m. The data unit 14 includes data indicating the contents of the specific message M and the ECU message m.

FIG. 3 is a block diagram showing the configuration of the relay connection unit 20.
The relay connection unit 20 includes a reception unit 21A and a transmission unit 22A connected to the first communication line 11A, a reception unit 21B and a transmission unit 22B connected to the second communication line 11B, a processing unit 23, and a storage unit 24. I have.
The receiving unit 21A receives the specific message MA transmitted from the specific ECU 30 to the first communication line 11A. The receiving unit 21A is provided with a first reception counter 25A, which records the number NA of received specific messages MA and the reception cycle T1A.
Furthermore, the receiving unit 21A receives the ECU message m transmitted from the ECUs 12A-1 and 12A-2 connected to the first communication line 11A. Note that no reception counter is provided for the ECU message m from the ECU 12.
The receiving unit 21B has the same configuration as the receiving unit 21A. The receiving unit 21B receives the specific message MB transmitted from the specific ECU 30 to the second communication line 11B, and is provided with a second reception counter 25B. The number NB of MBs and the reception cycle T1B are recorded.
The transmission unit 22 transmits specific messages MA, MB, and ECU message m to each communication line 11.

The processing unit 23 includes a relay processing unit 26, a routing map change unit 27, an ID change unit 28, and a communication abnormality detection unit 29.
The relay processing unit 26 relays the specific message M received from the other communication line to the one communication line 11 when the specific ECU 30 has an abnormality in communication with the one communication line 11.
When the ECU message m is received from the ECU 12, the relay transmission destination communication line is determined with reference to the routing map RM, and the ECU message m is transmitted to the communication line.

The communication abnormality detection unit 29 periodically accesses the first reception counter 25A and the second reception counter 25B, and reads the specific message number N and the reception cycle T1 recorded in each counter. The communication abnormality of the specific ECU 30 is detected by comparing the number N of the specific messages M received within the predetermined period T2 and the reception cycle T1 with the determination value provided in the communication abnormality detection unit 29 in advance.
For example, when the predetermined period T2 is set to 6 times the transmission cycle T3 in which the specific ECU 30 transmits the specific messages MA and MB and the determination value is 5, the number N of the specific messages M received during the predetermined period T2 is 5 If it is less than the number of times, it is determined that a communication abnormality has occurred in the specific ECU 30.
Further, for example, when the determination value (determination cycle) of the reception cycle T1 of the specific message M of the first reception counter 25A and the second reception counter 25B is set to 3, the reception cycle T1 is determined by the specific ECU 30 as the specific message MA, MB. If it is 3 times or more of the transmission cycle T3 for transmitting, it is determined that a communication abnormality has occurred in the specific ECU 30.

  In the ID changing unit 28, when the communication abnormality detecting unit 29 detects a communication abnormality to one communication line of the specific ECU 30, it is dedicated to receiving the specific message MA or MB received from the other communication line that is normally transmitted. The ID is changed to the relay ID stored in advance. The specific message M changed to the relay ID is referred to as a relay specific message MC.

When the communication abnormality detection unit 29 detects a communication abnormality to one communication line of the specific ECU 30, the routing map changing unit 27 displays information indicating the relay ID and the relay destination communication line of the relay specific message MC. In addition to the normal routing map RM1 stored in the storage unit 24, the storage unit 24 is instructed to rewrite the communication abnormal routing map RM2.
When the communication abnormality detection unit 29 detects that the communication of the specific ECU 30 is normally performed, the relay destination of the specific message M of the specific ECU 30 is deleted from the communication abnormality routing map RM2, and the normal routing map Rewriting to RM1 is instructed to the storage unit 24.

The storage unit 24 includes a routing map RM that indicates the relationship between the received specific message M and the relay destination communication line. When the specific ECU 30 normally transmits the specific message M, the specific message M transmitted by the specific ECU 30 is not described, and an ECU message is transmitted and received between the ECUs 12 other than the specific ECU 30 belonging to different communication lines. A normal routing map RM1 for relaying m is stored.
FIG. 4A shows an example of the normal routing map RM1 and shows to which communication line the IDs 1 to 4 transmitted from the ECUs 12 other than the specific ECU 30 are relayed.

On the other hand, when the communication abnormality detection unit 29 detects a communication abnormality to one communication line of the specific ECU 30, the specific message M of the specific ECU 30 received from the other communication line is transmitted according to a command from the routing map change unit 27. The communication abnormality routing map RM2 for relaying to one communication line is rewritten.
FIG. 4B shows an example of the communication abnormality routing map RM2, in which the relay ID of the relay specific message MC and the relay destination are added to the normal routing map RM1. That is, the communication abnormality routing map RM2 includes the normal routing map RM1.
For example, the reception-only ID of the specific message MA of the specific ECU 30 received from the first communication line 11A is rewritten as the relay ID 10, and the second communication line 11B is designated as the relay transmission destination. Similarly, the reception-only ID of the specific message MB of the specific ECU 30 received from the second communication line 11B is rewritten as the relay ID 20, and the first communication line 11A is designated as the relay transmission destination.

Next, the operation of the relay connection unit 20 will be described using the flowchart of FIG.
As an example, when the specific ECU 30 is transmitting the specific messages MA and MB whose reception-only ID is 30 to the first communication line 11A and the second communication line 11B, as shown in FIG. Consider a case in which a communication abnormality has occurred in which the specific message MA cannot be transmitted to the communication line 11A.

In step S1, the receiving unit 21 receives the specific messages MA and MB transmitted from the specific ECU 30 to the first communication line 11A and the second communication line 11B.
In step S2, the first reception counter 25A and the second reception counter 25B count the numbers NA and NB of the received specific messages MA and MB.
In step S3, the communication abnormality detection unit 29 periodically reads the numbers NA and NB of the specific messages MA and MB received from the first reception counter 25A and the second reception counter 25B and compares them with the determination values prepared in advance. . When the number N of received specific messages is smaller than the determination value, it is determined that a communication abnormality has occurred and the process proceeds to step S4. If the number N of received specific messages is greater than or equal to the determination value, it is determined that no communication abnormality has occurred and the process proceeds to step S8.
When the specific ECU 30 cannot transmit the specific message MA to the first communication line 11A, the specific message number N of the first reception counter 25A is 0, which is smaller than the determination value, and the communication abnormality detection unit 29 causes a communication abnormality. Judge that

In step S4, the routing map changing unit 27 rewrites, for example, the normal routing map RM1 shown in FIG. 4A to the communication abnormality routing map RM2 shown in FIG. 4B in which the relay ID and the relay destination are added. A command is issued to the storage unit 24. The routing map changing unit 27 stores the relay ID and the relay transmission destination in advance.
If the routing map RM in the storage unit 24 is already the communication abnormality routing map RM2, the routing map changing unit 27 may use the one already stored without rewriting the routing map RM.

In step S5, the ID changing unit 28 changes the reception-specific ID 30 of the specific message MB received from the normally transmitted second communication line 11B to the relay ID 20, and sets it as the relay specific message MC.
In step S6, the relay processing unit 26 performs a relay process for the relay specific message MC whose ID has been changed. With reference to the communication abnormality routing map RM2, it is determined that the relay transmission destination of the relay ID 10 is the second communication line 11B, and the relay identification message MC is transmitted to the second communication line 11B via the transmission unit 22.
In step S7, a normal relay process is performed that is not a relay of the specific message M of the specific ECU 30, but a relay of the ECU message m transmitted and received between the ECUs 12 other than the specific ECU 30 belonging to different communication lines. Since the communication abnormal routing map RM2 includes the normal routing map RM1, the normal relay processing is performed with reference to the communication abnormal routing map RM2.

  In step S8, when it is determined in step S3 that there is no abnormality in message transmission of the specific ECU 30, the routing map changing unit 27 deletes the relay transmission destination of the specific message M of the specific ECU 30 from the communication abnormality routing map RM2. The storage unit 24 is instructed to rewrite the normal routing map RM1. If the routing map RM in the storage unit 24 is already the normal routing map RM1, it may be used as it is without rewriting.

If the specific ECU 30 is normally transmitting to each communication line, the reception unit 21 receives the specific message M transmitted from the specific ECU 30 to the first communication line 11A and the second communication line 11B in step S1. In step S2, the number of received specific messages M is counted by the first reception counter 25A and the second reception counter 25B. In step S3, it is determined that no communication abnormality has occurred, and the process proceeds to step S8.
In step S8, the normal routing map RM1 is stored in the storage unit 24 in accordance with a command from the routing map change unit 27.
In step S7, referring to the normal routing map RM1, the ECU message m transmitted / received between the ECUs 12 other than the specific ECU 30 belonging to different communication lines is relayed, and is not involved in the relay of the specific message M of the specific ECU 30.

As described above, the relay specific message MC transmitted to the second communication line 11B is received by the ECUs 12B-1 and 12B-2 connected to the second communication line 11B.
The ECU 12B stores not only the reception dedicated ID of the specific message MB transmitted from the specific ECU 30, but also the relay ID of the relay specific message MC in advance, and the electronic device or the like connected to itself upon receiving the relay specific message MC Used for control.

  When the specific message MB is also transmitted from the specific ECU 30 with an abnormal cycle, the relay specific message MC and the specific message MB with the abnormal cycle are transmitted to the second communication line 11B. Selects the relay specific message MC and uses it for controlling an electronic device or the like.

According to the above configuration, the relay connection unit 20 receives the specific message M transmitted from the specific ECU 30 to the first communication line 11A and the second communication line 11B, and sets the number or / and the reception cycle of the specific message M to the first reception counter. Since it is recorded by 25A and the second reception counter 25B, communication is performed for transmission of the specific message M to the first communication line 11A or the second communication line 11B of the specific electronic control unit using the specific message number or / and the period. Whether or not an abnormality has occurred can be detected.
Further, the specific ECU 30 transmits the same specific message M to the first communication line 11A and the second communication line 11B, and the relay connection unit 20 cannot normally receive the specific message M from the other communication line, and the specific ECU 30 When the communication abnormality is detected, the relay connection unit 20 relays the specific message M of the specific ECU 30 received from one communication line to the other communication line instead of the specific ECU 30, so that the specific message is sent to the other communication line. The transmission of M can be reliably continued.

Note that the storage unit 24 of the relay connection unit 20 may be provided in advance with the normal routing map RM1 and the communication abnormality routing map RM2. In this case, the routing map changing unit 27 is not necessary for the processing unit 23, and when the communication abnormality detecting unit 29 detects a communication abnormality to one communication line of the specific ECU 30, the relay processing unit 26 displays the communication abnormality routing map RM2. Read from the storage unit 24 and perform relay processing. By switching between the normal routing map RM1 and the communication abnormality routing map RM2, it is not necessary to rewrite the routing map RM, and the processing time of the relay connection unit 20 is shortened.
In addition, the communication protocol is not limited to CAN, and may be an in-vehicle LAN protocol such as LIN or FlexRay.

It is a block diagram of the vehicle-mounted communication system which connected the relay connection unit of this invention. It is explanatory drawing of the flame | frame of a message. It is a block diagram which shows the structure of a relay connection unit. (A) is an example of a normal routing map, and (B) is an example of a communication abnormality routing map. It is a flowchart which shows operation | movement of a relay connection unit.

Explanation of symbols

11A First communication line 11B Second communication line 12 Electronic control unit (ECU)
20 relay connection unit 21 reception unit 22 transmission unit 23 processing unit 24 storage unit 25A first reception counter 25B second reception counter 26 relay processing unit 27 routing map change unit 28 ID change unit 29 communication abnormality detection unit 30 specific ECU
m ECU message MA, MB specific message MC relay specific message RM1 normal routing map RM2 communication abnormal routing map

Claims (5)

A relay connection unit that connects between a first communication line and a second communication line to which an electronic control unit is connected, respectively, and relays message transmission / reception between the electronic control units connected to the first and second communication lines. And
Connected to the specific electronic control unit that is connected to both the first and second communication lines and directly transmits and receives messages, and is connected via the first and second communication lines to receive messages transmitted by the specific electronic control unit. A receiving unit to
A first reception counter that records the number or / and the reception cycle of the message transmitted from the specific electronic control unit received by the reception unit to the first communication line;
A second reception counter that records the number or / and the reception cycle of the message transmitted from the specific electronic control unit received by the reception unit to the second communication line;
Abnormality in message transmission from the specific electronic control unit to the first communication line or the second communication line by comparing the number of messages and / or the period recorded in the first reception counter and the second reception counter with a determination value A processing unit that relays to the other communication line that has not received the message of the specific electronic control unit received from one communication line,
An in-vehicle relay connection unit comprising:   The in-vehicle relay connection unit according to claim 1, wherein the specific electronic control unit connected via the first and second communication lines is an electronic control unit that controls a traveling system device. A storage unit having a routing map showing a relationship between a message to be received and a relay destination;
When the processing unit detects that a message is not transmitted from the specific electronic control unit to the first communication line or the second communication line, the routing unit routes the relay destination communication line of the message of the specific electronic control unit. The in-vehicle relay connection unit according to claim 1, wherein rewriting to be added to a map is instructed to the storage unit.   The processing unit is configured to change an ID dedicated to reception of the message of the specific electronic control unit received from the one communication line to a relay ID when relaying to the other communication line. Item 4. The in-vehicle relay connection unit according to any one of items 3 to 4.   The processing unit compares the number of messages and / or the reception period stored in the first reception counter and the second reception counter with a determination value, and from a state in which no message is transmitted from the specific electronic control unit. 5. The storage unit according to claim 3 or 4, wherein when it is detected that the transmission has been returned, the storage unit is instructed to rewrite the relay transmission destination of the message of the specific electronic control unit from the routing map. In-vehicle relay connection unit.

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