Onboard communication system, onboard relay device and message relay procedure

Abstract

Onboard communication system, comprehensive: an on-board relay device (5) to which several bus communication lines (1a - 1d) mounted in a vehicle (1) are connected, for relaying messages between the communication lines (1a - 1d); several first onboard communication devices (12 - 33), each connected to exactly one of the several communication lines (1a - 1d); and a second onboard communication device (11) which is connected to at least two of the several communication lines (1a - 1d), wherein the second onboard communication device (11) includes a forwarding processing unit (41a) for specific messages for performing, if a specific message is received through one of the connected communication lines (1a - 1d), processing to send the specific message through another of the communication lines (1a - 1d), the onboard relay device (5) contains: an investigative unit (51a) to determine whether the specific message received through one of the connected communication lines (1a - 1d) meets a predetermined rejection condition; a forwarding processing unit (51b) for specific messages, which is configured not to forward the specific message if the investigation unit (51a) determines that the specific message meets the rejection condition, and to carry out processing to send the specific message through another of the communication lines (1a - 1d) if the investigation unit (51a) determines that the specific message does not meet the rejection condition; a storage unit (52) for storing identification information contained in the forwarded specific message; and a timer unit (51c) for measuring an elapsed time since the transmission of the specific message for each component of the identification information stored in the storage unit (52); wherein the investigation unit (51a) of the onboard relay device (5) is configured to determine, for each specific message containing identification information for which the elapsed time measured by the timer unit (51c) is within a predetermined time, whether identification information contained in a specific message previously sent by the relay processing unit (51b) of the onboard relay device (5) matches identification information contained in the specific message received through one of the communication lines (1a - 1d), and The forwarding processing unit (51b) for specific messages will not forward the specific message if the investigation unit (51a) determines that the identification information matches.

Description

TECHNICAL AREA

[0001] The present invention relates to an on-board communication system, an on-board forwarding device and a message forwarding method for forwarding messages between several communication lines mounted in a vehicle. TECHNICAL BACKGROUND

[0002] A large number of devices, such as ECUs (Electronic Control Units), are installed in a vehicle. These devices are connected via communication lines and interact by exchanging messages through sending and receiving. According to current technology, the CAN (Controller Area Network) communication protocol has been widely used for communication within vehicles. The CAN communication protocol uses a bus network configuration where multiple communication devices are connected via a single communication line. In recent years, the number of devices installed in a vehicle has increased; however, the number of devices that can be connected to a CAN bus has an upper limit.Consequently, in many cases several CAN buses are installed in a vehicle, and the CAN buses are connected to a forwarding device such as a gateway, and the forwarding device forwards messages between the CAN buses.

[0003] According to the state of the art, a vehicle is also equipped with a diagnostic function for on-board devices. The diagnostic device, located at a vehicle dealership or similar location, collects information from on-board devices, for example, by connecting the diagnostic device to a specific connector provided in the vehicle. Based on the collected information, the diagnostic device can then diagnose, for example, whether a defect exists in the vehicle. At this point, the diagnostic device can send a broadcast to the vehicle's network requesting the collection of information. If an on-board device that has received the broadcast sends information back to the diagnostic device, the vehicle's information collection is carried out by the diagnostic device.

[0004] If the relay unit receives a broadcast from the diagnostic device, it forwards the broadcast to all communication lines except the one from which it was received and then relays the broadcast to all communication devices. In recent years, network configurations in vehicles have become more complex, and in addition to the relay unit, communication devices connected to multiple communication lines may be present in the vehicle. If a communication device connected to multiple communication lines is present, a communication loop may be formed between the communication device and the relay unit.If such a communication loop exists, and the communication device connected to the multiple communication lines forwards a broadcast, the forwarding of the broadcast between the communication device and the forwarding device can continue repeatedly.

[0005] In JP 2017 - 5367 A, a communication system is disclosed which prevents a broadcast frame from circulating in a network configuration in which several Ethernet (registered trademark) switches are connected in a ring, if the Ethernet switches receive a broadcast frame, by comparing the sending source MAC address contained in the broadcast frame with the MAC address registered in their own MAC address table and determining whether the broadcast frame should be discarded.

[0006] DE 102 30 351 A1 discloses a gateway ECU that identifies a requested ECU from a plurality of ECUs via a LAN based on an access request from an external device requesting access to the requested ECU and determines, based on initial authentication information from the external device, whether the external device is authorized to access the ECUs. Furthermore, the gateway ECU determines, based on data transmitted over the LAN from each ECU, whether a fault is currently present in the vehicle. If a fault is present, the gateway ECU identifies a faulty component causing the current fault in the vehicle, based on information transmitted by each corresponding ECU, by executing a data acquisition / diagnostic program performed by a customer server. OVERVIEW OF THE INVENTION TASKS TO BE SOLVED BY THE INVENTION

[0007] The communication system disclosed in JP 2017-5367A is based on a network configuration where multiple Ethernet switches are connected in a ring. Consequently, the system cannot operate using the CAN communication protocol, which is a bus network configuration. Furthermore, a function is required to determine whether the broadcast frame should be discarded in all of the Ethernet switches connected in the ring. Therefore, the cost increases with the scale of the network.

[0008] The present invention was made in light of these circumstances, and it is an object of the present invention to provide an onboard communication system, an onboard forwarding device and a message forwarding method that are capable of preventing the repetition of a message in a bus network configuration. MEANS OF SOLVING THE TASK

[0009] An onboard communication system comprises the features of claim 1.

[0010] Furthermore, in the onboard communication system according to the present invention, the detection unit of the onboard forwarding device is configured to determine whether identification information contained in a specific message previously sent by the forwarding processing unit of the onboard forwarding device matches identification information contained in the specific message received through one of the communication lines, and the forwarding processing unit for specific messages may not forward the specific message if the detection unit determines that the identification information matches.

[0011] Furthermore, in the onboard communication system according to the present invention, the detection unit of the onboard forwarding device can be configured to determine whether identification information contained in a specific message previously sent by the forwarding processing unit of the onboard forwarding device matches identification information contained in the specific message received through one of the communication lines, and to determine whether the communication line through which the previous specific message, whose identification information matches, was received and the communication line through which the current specific message is received are different from each other, and the forwarding processing unit for specific message can be configured not to forward the specific message if the detection unit determines thatthat the identification information matches and the two communication lines are different from each other.

[0012] Furthermore, in the onboard communication system according to the present invention, the onboard forwarding device comprises: a storage unit for storing identification information contained in the forwarded specific message; and a timer unit for measuring an elapsed time since the transmission of the specific message for each component of the identification information stored in the storage unit, wherein the detection unit of the onboard forwarding device performs the detection for each specific message containing identification information for which the elapsed time measured by the timer unit is within a predetermined time.

[0013] Furthermore, in the on-board communication system according to the present invention, the multiple communication lines can include a communication line to which a connector for connecting and disconnecting a diagnostic device of the vehicle is connected, and the diagnostic device connected to the connector can send the specific message to the communication line.

[0014] Furthermore, in the on-board communication system according to the present invention, the several first communication devices can include a wireless communication device for performing wireless communication with the vehicle's diagnostic device, and the wireless communication device can send the specific message received by wireless communication from the diagnostic device to the vehicle's communication line.

[0015] Furthermore, an onboard forwarding device according to the present invention is an onboard forwarding device having the features of claim 5.

[0016] Furthermore, a message forwarding method according to the present invention is a message forwarding method having the features of claim 6.

[0017] In the present invention, the onboard communication system employs a bus network configuration in which the multiple onboard communication devices are connected to the same communication line (i.e., a bus). The system connects the multiple communication lines provided in the vehicle to the onboard relay device, which then forwards messages between the communication lines. Furthermore, the communication devices included in the onboard communication system comprise a first onboard communication device connected to one communication line and a second onboard communication device connected to at least two communication lines. If the second onboard communication device receives a specific message through one communication line, it forwards the specific message to other communication lines.

[0018] If the onboard relay unit, to which the multiple communication lines are connected, receives a specific message through one of the communication lines, the relay unit determines whether the specific message meets a predetermined rejection condition. If it is determined that the specific message meets the rejection condition, the relay unit rejects the specific message without forwarding it. If it is determined that the received specific message does not meet the rejection condition, the relay unit forwards the specific message.

[0019] In this way, the second onboard communication device can forward a specific message without performing the determination regarding the rejection condition, and the onboard forwarding device can prevent the forwarding of the specific message from being repeated.

[0020] Furthermore, in the present invention, the onboard forwarding device compares the identification information contained in the specific message that was previously forwarded with the identification information contained in the specific message that was newly received, and performs a determination on the condition that the identification information matches. In this way, the onboard forwarding device can prevent a specific message that is likely to be the same as the previously forwarded specific message from being forwarded again.

[0021] Furthermore, in the present invention, the onboard forwarding device performs a determination as described above, provided that the identification information matches and the communication line through which a specific message was previously received and the communication line through which a specific message is received this time are different. If a specific message with the same identification information is received through a different communication line, it is likely that this specific message is a specific message that is cyclically forwarded by the second onboard forwarding device. Consequently, it is possible to prevent such a specific message from being forwarded again.

[0022] Furthermore, in the present invention, if the onboard forwarding device forwards a specific message, the onboard forwarding device stores the identification information of the specific message and also measures the time elapsed since the transmission of the specific message for each component of the identification information. The onboard forwarding device determines whether the identification information whose elapsed time is within the predetermined time period satisfies the rejection condition, and does not include the identification information for which the predetermined time period or more has elapsed since the previous transmission as the target for determining whether the rejection condition is met.By including such a time limit in the investigation, for example if a specific message was correctly resent after a predetermined period of time has elapsed, it is possible to prevent the valid specific message from being discarded.

[0023] It should be noted that the specific message is, for example, a broadcast or a message relating to the vehicle's diagnostics. It is highly likely that such a message will be relayed by the second onboard communication device to which the multiple communication lines are connected. Accordingly, such a message can be repeatedly relayed by the onboard relay device and the second onboard relay device. Therefore, by identifying these messages as the specific messages under the rejection condition, it is possible to prevent the repeated relaying of the specific message.

[0024] It should be noted that the specific message can also be a message that is neither a broadcast nor a message relating to the vehicle's diagnostics. The specific message can also be any message, provided it can be relayed by the second on-board communication device.

[0025] Furthermore, the multiple communication lines to be connected to the onboard relay device include a communication line to which a connector for attaching and detaching the vehicle's diagnostic equipment is connected, and the diagnostic equipment connected to the connector transmits a specific message. Alternatively, the first onboard communication device includes a wireless communication device that performs wireless communication with the vehicle's diagnostic equipment, and the wireless communication device forwards a specific message received from the diagnostic equipment to the communication lines in the vehicle. The onboard relay device can prevent the specific message sent by such an external diagnostic device from being repeatedly relayed within the vehicle's network. ADVANTAGEOUS EFFECTS OF THE INVENTION

[0026] According to the present invention, repeated forwarding in a bus network configuration can be prevented by using a configuration in which a specific message received by the onboard forwarding device through one communication line is not forwarded if the specific message meets the rejection condition, and the specific message is sent through another communication line if the specific message does not meet the rejection condition. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a schematic representation showing the configuration of an onboard communication system according to the present embodiment. Fig. Figure 2 is a schematic view showing an example of the configuration of the onboard communication system where there is no looping of diagnostic messages. Fig. Figure 3 is a block diagram showing the configuration of a gateway according to the present embodiment. Fig. Figure 4 is a block diagram showing the configuration of an ECU according to the present embodiment. Fig. Figure 5 is a block diagram showing the configuration of the ECU according to the present embodiment. Fig. Figure 6 is a schematic view showing an example of redirect ID information and a redirect flag stored in the storage unit. Fig. Figure 7 is a flowchart showing a processing procedure for forwarding and discarding a diagnostic message, performed by the gateway. FORMS OF EXECUTION OF THE INVENTION System configuration

[0027] Fig. Figure 1 is a schematic view showing the configuration of an on-board communication system according to the present embodiment. The on-board communication system according to the present embodiment is configured such that several ECUs 11 to 13, 21 to 23, and 31 to 33, mounted in a vehicle 1, send and receive messages via several communication lines 1a to 1c and a gateway 5, which is also mounted in the vehicle 1. More precisely, the several communication lines 1a to 1c are arranged at suitable positions in the vehicle 1. These communication lines 1a to 1c are connected to the gateway 5, and the gateway 5 forwards messages between the communication lines 1a to 1c. In the present embodiment, ECUs 11 to 13 are connected to communication line 1a, ECU 11 and ECUs 21 to 23 are connected to communication line 1b, and ECUs 31 to 33 are connected to communication line 1c.In the present embodiment, the ECU 11 is connected to the two communication lines 1a and 1b and can send messages to and receive messages from the communication lines 1a and 1b.

[0028] Furthermore, in the present embodiment, a connector 6 for detachably connecting a diagnostic device 7 for diagnosing the vehicle 1 is arranged at a suitable position. The connector 6 is connected to the gateway 5 via a communication line 1d. The diagnostic device 7 is, for example, a device provided at a dealership, a workshop for the vehicle 1, or the like, and is connected to the connector 6 of the vehicle 1 via a cable 7a. The diagnostic device 7 connected to the connector 6 communicates with the ECUs 11 to 13, 21 to 23, and 31 to 33 of the vehicle 1 via the communication lines 1a to 1d and the gateway 5 to obtain various information from the vehicle 1 and to diagnose whether a defect or the like exists in the vehicle 1.

[0029] In the onboard communication system according to the present embodiment, the CAN communication protocol is used for communication between devices. This means that the ECUs 11 to 13, 21 to 23, and 31 to 33, and the gateway 5, send and receive messages according to the CAN communication protocol via communication lines 1a to 1c. Furthermore, in the present embodiment, the diagnostic device 7 also sends and receives messages according to the CAN communication protocol. Accordingly, the communication lines 1a to 1d are two-line buses for sending and receiving different signals; these are called CAN buses. However, the onboard communication system can also be configured to communicate using a communication protocol other than CAN, such as LIN (Local Interconnect Network) or FlexRay.It is also possible to use a configuration that mixes multiple communication protocols. In this case, for example, Gateway 5 can be configured to perform protocol conversion when forwarding messages.

[0030] In the present embodiment, the ECU 33 has a function for performing wireless communication using, for example, a public mobile communication network or a wireless LAN (Local Area Network). With this configuration, the ECU 33 can exchange messages, for example, with a server device 8 installed outside the vehicle 1. The server device 8 is a device operated, for example, by a manufacturer or distributor of the vehicle 1. The server device 8 communicates with the vehicle 1 at predetermined intervals or periodically, receives various types of information from the vehicle 1, and diagnoses whether the vehicle 1 is defective or not. This means that the server device 8 is a diagnostic device that remotely diagnoses the vehicle 1.

[0031] When vehicle 1 is being diagnosed, for example, an operator at the vehicle 1 dealership connects the diagnostic device 7 to the connector 6 of vehicle 1 via cable 7a and starts the diagnostic process. In this way, the diagnostic device 7 sends a message requesting the transmission of predetermined information through cable 7a to the devices installed in vehicle 1. The message sent by the diagnostic device 7 at this time is a so-called broadcast, which is simultaneously sent to all devices of vehicle 1 being diagnosed. In the present embodiment, a broadcast sent by the diagnostic device 7 for diagnostic purposes is referred to as a diagnostic message.

[0032] The diagnostic message sent by diagnostic device 7 is received by gateway 5 via cable 7a, connector 6, and communication line 1d. Gateway 5, having received the diagnostic message, forwards it to all communication lines 1a to 1c, except for communication line 1d, through which the diagnostic message was received. The diagnostic message sent by gateway 5 to communication lines 1a to 1c is received by ECUs 11 to 13, 21 to 23, and 31 to 33, which are connected to the respective communication lines 1a to 1c.

[0033] ECUs 11 to 13, 21 to 23, and 31 to 33, which have received the diagnostic message, send information required for the diagnostic process of diagnostic device 7 to communication lines 1a to 1c. Once gateway 5 has received the messages in response to the diagnostic message from ECUs 11 to 13, 21 to 23, and 31 to 33, it forwards the received messages to communication line 1d, thereby sending the messages to diagnostic device 7, which is connected to connector 6. When diagnostic device 7 has received the messages from vehicle 1, it gathers the information contained in the received messages and diagnoses the presence or absence of an anomaly in vehicle 1 based on the gathered information.

[0034] In this embodiment, the onboard communication system includes the ECU 11, which is connected to the two communication lines 1a and 1b. The ECU 11 can send and receive messages to and from the communication lines 1a and 1b. Furthermore, when the ECU 11 receives a broadcast through one of the communication lines 1a or 1b, it transmits the broadcast through the other communication line and forwards it.

[0035] Accordingly, if ECU 11 receives a diagnostic message from diagnostic device 7 via communication line 1a, as explained above, it forwards the received diagnostic message via communication line 1b, since the diagnostic message is a broadcast. The diagnostic message forwarded by ECU 11 from communication line 1a to communication line 1b is received by gateway 5 via communication line 1b. If gateway 5 has received a diagnostic message via communication line 1b, it forwards the diagnostic message to the other communication lines 1a, 1c, and 1d. The diagnostic message forwarded by gateway 5 is received by ECU 11 via communication line 1a, and ECU 11, having received the diagnostic message, forwards it to communication line 1b.

[0036] Therefore, if Gateway 5 and ECU 11 forward a diagnostic message, a situation can arise in which the diagnostic message is continuously forwarded in the on-board communication system. Fig. 1 is indicated by an arrow with two dots and a dash, along which the forwarding of the diagnostic message is repeated. Although not shown, the same situation occurs if ECU 11 forwards a diagnostic message from communication line 1b to 1a. The repetition of such a diagnostic message (hereinafter referred to as "diagnostic message looping") is attributable to the formation of a communication path with a loop through gateway 5 and ECU 11 in the onboard communication system.

[0037] Fig. Figure 2 is a schematic representation showing an example of the configuration of an onboard communication system where no diagnostic message loop is present. The in Fig. The onboard communication system shown in Figure 2 is configured such that communication line 1b is not connected to gateway 5 in the diagram. Fig. The onboard communication system shown in Figure 1 is connected. ECU 11, to which the two communication lines 1a and 1b are connected, can be an ECU designed based on the assumption that, for example, a tree-like network is formed. ECU 11 operates as the master ECU, and ECUs 21 to 23, connected to ECU 11 via communication line 1b, operate as subordinate ECUs. Therefore, if ECU 11 receives a broadcast via communication line 1a, it must forward the broadcast to the subordinate ECUs 21 to 23. Accordingly, ECU 11 is equipped with the aforementioned forwarding function.

[0038] However, if, for example, the ECU 11 is generally installed in vehicles 1 of different grades, specifications, and models, or if the system configuration is changed during the development process of vehicle 1, a network configuration may be formed that differs from the assumption of the ECU 11. For example, if in Fig. 2. Since ECU 21 needs to communicate with ECU 31, it takes time to obtain information if the communication is carried out via ECU 11. Therefore, if communication line 1b is directly connected to gateway 5 and ECU 21 and ECU 31 communicate directly via gateway 5, the following can occur: Fig. The system configuration shown in 1 is formed. In this case too, if ECU 11 forwards a broadcast, a [configuration] occurs in Fig. Figure 1 shows the loop formation of a diagnostic message. The reason why the loop network configuration is formed in the onboard communication system is not limited to this.

[0039] It should be noted that, although the case described involves performing the diagnosis by connecting the diagnostic device 7 to the connector 6 of the vehicle 1, this is not the only possible method. If the server device 8 sends a diagnostic message to the ECU 33 via wireless communication, a similar loop of the diagnostic message can also occur. This means that a similar loop of diagnostic messages is caused by the ECU 33, which has received a diagnostic message from the server device 8, which sends the diagnostic message to communication line 1c; the gateway 5, which has received the diagnostic message via communication line 1c, which forwards the diagnostic message to communication lines 1a, 1b, and 1b; and the ECU 11, which has received the diagnostic message via communication line 1a, which forwards the diagnostic message to communication line 1b.

[0040] In the onboard communication system according to the present embodiment, the gateway 5 has a function for preventing the occurrence of such a diagnostic message loop. When the gateway 5 according to the present embodiment receives a diagnostic message (or a broadcast) through one of the communication lines 1a to 1d, the gateway 5 determines whether the received diagnostic message is the same as or different from the diagnostic messages it previously sent. If the received diagnostic message is the same as any of the previously sent diagnostic messages, the gateway 5 discards the diagnostic message without forwarding it.If the received diagnostic message differs from the previously sent diagnostic messages, Gateway 5 forwards the diagnostic message by sending it from communication lines 1a to 1d, with the exception of communication lines 1a to 1d that received the diagnostic message. Device configuration

[0041] Fig. Figure 3 is a block diagram showing the configuration of gateway 5 according to the present embodiment. Gateway 5 according to the present embodiment comprises a processing unit 51, a memory unit 52, and several communication units 53. The processing unit 51 is, for example, constructed using an arithmetic processing unit such as a CPU (central processing unit) or an MPU (microprocessing unit) and performs various processes by reading and executing a program stored in a ROM (read-only memory) or the like (not shown). In the present embodiment, the processing unit 51 performs forwarding processing of messages between communication lines 1a to 1d and discarding of unnecessary messages.

[0042] The memory unit 52 is, for example, constructed using a memory element such as SRAM (static random-access memory) or DRAM (dynamic random-access memory). The memory unit 52 stores data and the like that generated by the processing unit 51 during the processing process. In the present embodiment, the memory unit 52 stores forwarding ID information 52a, which is information relating to an ID of a diagnostic message that is forwarded by the forwarding processing of the processing unit 51, and a forwarding flag indicating that no predetermined time interval has yet elapsed since the diagnostic message was forwarded.

[0043] The communication units 53 are each connected to one of the communication lines 1a to 1d and send and receive messages via the connected communication lines 1a to 1d. According to the present embodiment, the communication units 53 perform communication processing according to the CAN communication protocol. The communication units 53 send messages by converting a transmit message supplied by the processing unit 51 into an electrical signal and outputting the electrical signal to the communication lines 1a to 1d. The communication units 53 also receive messages by sensing and recording the potentials of the communication lines 1a to 1d and supplying the received message to the processing unit 51.

[0044] Furthermore, according to the present embodiment, the processing unit 51 of the gateway 5 executes the program stored in the ROM or the like, thereby realizing a rejection condition determination unit 51a, a forwarding processing unit 51b, a timer unit 51c, and the like as software function blocks. If a diagnostic message (or a broadcast) is received from one of the communication units 53, the rejection condition determination unit 51a determines whether the received diagnostic message satisfies a predetermined rejection condition. Details of the rejection condition used by the rejection condition determination unit 51a for this determination are described later.

[0045] By delivering a message received by one of the communication units 53 to the other communication units 53, the forwarding processing unit 51b forwards the message. By delivering a diagnostic message, for which the rejection condition determination unit 51a has determined that the rejection condition is not met, to the communication units 53 except for the communication unit 53 that received the diagnostic message, the forwarding processing unit 51b forwards the diagnostic message. It should be noted that the forwarding process for normal messages (messages that are not diagnostic messages or broadcasts) is carried out by the gateway 5 using existing technology, so its description is omitted.

[0046] The timer unit 51c, also referred to as a "timer," measures the elapsed time of a process. In the present embodiment, the timer unit 51c measures the time elapsed after a diagnostic message has been forwarded by the gateway 5. Furthermore, the timer unit 51c can measure an elapsed time individually for each ID attached to the diagnostic message and can thus measure multiple elapsed time periods in parallel. The elapsed time measured by the timer unit 51c is used for determination by the rejection condition determination unit 51a.

[0047] Fig. Figure 4 is a block diagram showing the configuration of the ECU 11 according to the present embodiment. Fig. Figure 4 shows functional blocks relating to the communication of the ECU 11, while functional blocks relating to the control of the vehicle 1 are omitted. The ECU 11 according to the present embodiment comprises a processing unit 41, a memory unit 42, and two communication units 43. The processing unit 41 is constructed using an arithmetic processing unit such as a CPU and an MPU and performs various types of processing, such as communication processing and control processing, by reading and executing the program stored in the memory unit 42. The memory unit 42 is constructed using a non-volatile memory element such as flash memory or an EEPROM (electrically erasable programmable read-only memory).The storage unit 42, for example, stores a program executed by the processing unit 41 and data required for the program's execution. The two communication units 43 are connected to communication lines 1a and 1b, respectively, and send and receive messages according to the CAN communication protocol via these lines.

[0048] Furthermore, according to the present embodiment, the processing unit 41 of the ECU 11 executes the program stored in the memory unit 42, thereby implementing the forwarding processing unit 41a as a software function block. When a communication unit 43 receives a diagnostic message (or a broadcast), the forwarding processing unit 41a transmits the diagnostic message through the other communication unit 43, thus forwarding the diagnostic message. It should be noted that the forwarding processing unit 41a can also be configured to forward the diagnostic message in only one direction, such as forwarding a diagnostic message from communication line 1a to communication line 1b, but not forwarding the diagnostic message from communication line 1b to communication line 1a.

[0049] The configuration of ECUs 12, 13, 21 to 23, 31 and 32, which are connected to only one of the communication lines 1a to 1c, is omitted from the block diagram. These ECUs 12, 13, 21 to 23, 31 and 32 are essentially the same as the configuration with only one communication unit 43 in the configuration shown in Fig. 4 ECU 11 shown and do not perform forwarding processing of a diagnostic message.

[0050] Fig. Figure 5 is a block diagram showing the configuration of the ECU 33 according to the present embodiment. Fig. Figure 5 shows functional blocks relating to the communication of the ECU 33, while functional blocks relating to the control of the vehicle 1 are omitted. The ECU 33 according to the present embodiment comprises a processing unit 46, a memory unit 47, a communication unit 48, and a wireless communication unit 49. The processing unit 46 is constructed using an arithmetic processing unit such as a CPU and an MPU and performs various types of processing, such as communication processing and control processing, by reading and executing the program stored in the memory unit 47. The memory unit 47 is constructed using a non-volatile memory element such as flash memory or an EEPROM.The storage unit 47, for example, stores a program executed by the processing unit 46 and the data required for the program's execution. The communication unit 48 sends and receives messages according to the CAN communication protocol via the communication line 1c.

[0051] The wireless communication unit 49 can communicate with the server device 8 installed outside the vehicle 1 by establishing wireless communication using, for example, a cellular communication network, a wireless LAN, or the like. The wireless communication unit 49 wirelessly transmits messages by outputting signals obtained by modulating transmit messages supplied by the processing unit 46 from an antenna (not shown). The wireless communication unit 49 also delivers received messages, obtained by demodulating signals received from the antenna, to the processing unit 46.

[0052] Furthermore, according to the present embodiment, the processing unit 46 of the ECU 33 executes the program stored in the memory unit 47, thereby realizing the forwarding processing unit 46a as a software function block. The forwarding processing unit 46a performs the processing for forwarding messages between the wired communication in the vehicle 1 and the wireless communication with the server device 8. In the present embodiment, the forwarding processing unit 46a forwards a diagnostic message by sending the diagnostic message received by the wireless communication unit 49 from the server device 8 via the communication unit 48 to the communication line 1c.Furthermore, the forwarding processing unit 46a sends the messages received by the individual ECUs 11 to 13, 21 to 23, 31 and 32 in vehicle 1 to the server device 8 via the wireless communication unit 49 in response to the diagnostic message. It should be noted that, since the communication protocol differs between the wired communication in vehicle 1 and the wireless communication with the server device 8, the forwarding processing unit 46a performs processing to convert the format of the message to be forwarded. Forwarding and discarding of messages by gateway

[0053] As explained above, in the onboard communication system according to the present embodiment, gateway 5 determines whether the diagnostic message should be forwarded or discarded to prevent the diagnostic message from looping. The details of the determination process by gateway 5 are described below. It should be noted that the following describes the determination of whether the diagnostic message sent by diagnostic device 7 should be forwarded or discarded. A description of the determination process for a diagnostic message sent by server device 8 is omitted.

[0054] In the onboard communication system according to the present embodiment, since communication is carried out according to the CAN communication protocol, a message to be sent and received (a data frame) contains a decision field, a control field, a data field, a CRC (Cyclic Redundancy Field), an ACK field, and the like. The control field of the message contains a CAN ID that specifies the type of message. In the present embodiment, the diagnostic message sent by the diagnostic device 7 (the diagnostic message sent by the server device 8 and forwarded by the ECU 33) has the same configuration. It should be noted that the data field in the diagnostic message contains a service ID that specifies the type of diagnostic processing and the like.

[0055] The rejection condition determination unit 51a of gateway 5 determines, based on the CAN IDs and service IDs contained in the diagnostic messages, whether the diagnostic messages are the same or different. This means that if two diagnostic messages are present, the rejection condition determination unit 51a determines that the two diagnostic messages are the same if both the CAN ID and the service ID match, and determines that the two diagnostic messages are different if the CAN ID and / or the service ID do not match.

[0056] When it forwards a diagnostic message, the forwarding processing unit 51b of the gateway 5 stores information about the diagnostic message, such as the forwarding ID information 52a, in the storage unit 52 and sets the forwarding flag 52b. Fig. Figure 6 is a schematic view showing an example of the forwarding ID information 52a and the forwarding flags 52b stored in memory unit 52. The forwarding ID information 52a in memory unit 52 contains the CAN ID and service ID included in the forwarded diagnostic message, linked to information about the receiving source of the diagnostic message. The receiving source information contained in forwarding ID information 52a identifies the communication lines 1a to 1b that received the forwarded diagnostic message (note that this information need not be for identifying communication lines 1a to 1d, but could also be for identifying the communication unit 53).

[0057] The forwarding flag 52b, stored in memory unit 52, is set to either "0" or "1". For each diagnostic message containing the information in forwarding ID information 52a, forwarding flag 52b is set to "1" for a predetermined time period (e.g., 100 milliseconds to a few seconds) after the forwarding is performed and set to "0" after the predetermined time period has elapsed. The predetermined time period is measured at this point by the timer unit 51c.

[0058] When the rejection condition determination unit 51a of the gateway 5 receives a diagnostic message through one of the communication lines 1a to 1d, the rejection condition determination unit 51a compares the received diagnostic message with the forwarded diagnostic message in which the forwarding ID information 52a is stored in the memory unit 52, and determines whether the predetermined rejection condition is met. In the present embodiment, the rejection condition is that all of the following three conditions are met: Both the CAN IDs and the service IDs match. The sources of reception vary. The forwarding flag is "1".

[0059] The rejection condition determination unit 51a specifies that the rejection condition is met if all three of the above conditions are met, and specifies that the rejection condition is not met if one or more of the three above conditions are not met. The condition contained in the rejection condition that "the CAN ID and the service ID match" is a condition to specify that the diagnostic messages are the same, as explained above. Even if diagnostic messages have the same CAN ID and the same service ID, they can still be valid diagnostic messages from diagnostic device 7, for example, the retransmission of the same diagnostic message. Accordingly, the condition that "the receiving sources are different" is specified as a rejection condition to prevent such a diagnostic message from being rejected.The condition that “the forwarding flag is “1”” is defined as a rejection condition to prevent a diagnostic message with the same content as a diagnostic message whose information is registered in the forwarding ID information 52a from not being forwarded for a long period of time.

[0060] The forwarding processing unit 51b of gateway 5 sends the diagnostic message, for which the rejection condition determination unit 51a has determined that the rejection condition is not met, to communication lines 1a to 1d that are not the receiving source of the diagnostic message, in order to forward the diagnostic message. Forwarding processing unit 51b discards the diagnostic message for which the rejection condition determination unit 51a has determined that the rejection condition is met, without sending the diagnostic message to the other communication lines 1a to 1d. To discard the diagnostic message, it is only necessary not to forward it; it is not necessary for the diagnostic message to be deleted from memory, buffers, or the like.

[0061] Fig.Figure 7 is a flowchart showing a processing procedure for forwarding or discarding a diagnostic message, executed by the gateway 5. According to the present embodiment, the processing unit 51 of the gateway 5 determines whether a message has been received from one of the communication units 53 (step S1). If no message has been received (NO in step S1), the processing unit 51 waits until a message is received. If a message has been received (YES in step S1), the processing unit 51 determines, based on the CAN ID and the service ID of the received message, whether the received message is a diagnostic message.If the received message is not a diagnostic message (NO in step S2), the forwarding processing unit 51b of processing unit 51 performs forwarding processing by a procedure suitable for this message (step S3) and terminates the processing.

[0062] If the received message is a diagnostic message (YES in step S2), the rejection condition determination unit 51a of the processing unit 51 reads the forwarding ID information 52a and the forwarding flag 52b, which are stored in the memory unit 52 (step S4). The rejection condition determination unit 51a compares the CAN ID and service ID contained in the received diagnostic message with the CAN ID and service ID, respectively, stored in the forwarding ID information 52a and determines whether the received diagnostic message is the same as a previously forwarded diagnostic message (step S5).

[0063] If it is determined that the received diagnostic message is the same as a previously forwarded diagnostic message (YES in step S5), the rejection condition determination unit 51a compares the communication lines 1a to 1c, which are the receive source of the received diagnostic message, with the information of the receive source of the previously forwarded identical diagnostic message to determine whether the receive sources are different (step S6). If it is determined that the receive source of the received diagnostic message differs from the receive source of the previously forwarded diagnostic message (YES in step S6), the rejection condition determination unit 51a determines whether the value of the forward flag 52b associated with the previously forwarded diagnostic message is "1" (step S7).If the forwarding flag 52b is "1" (YES in step S7), the rejection condition determination unit 51a determines that the rejection condition for the received diagnostic message is met. Then, the rejection condition determination unit 51a rejects the diagnostic message (step S8) without forwarding it and terminates processing.

[0064] The rejection condition determination unit 51a determines that the rejection condition is not met if the received diagnostic message is not the same as the previously forwarded diagnostic message (NO in step S5), if it is determined that the receiving source of the received diagnostic message is the same as the receiving source of the previously forwarded diagnostic message (NO in step S6), or if it is determined that the value of the forwarding flag 52b associated with the previously forwarded diagnostic message is "0" (NO in step S7). In these cases, the forwarding processing unit 51b forwards the received diagnostic message to processing unit 51.

[0065] In the diagnostic message forwarding process, the forwarding processing unit 51b first stores information such as the CAN ID, the service ID, and the receiving source of the diagnostic message to be forwarded in the storage unit 52 as the forwarding ID information 52a (step S9). Next, the forwarding processing unit 51b sets the value of the forwarding flag 52b corresponding to the stored forwarding ID information 52a to "1" (step S10) and starts the timing measurement by the timer unit 51c (step S11). Afterward, the forwarding processing unit 51b forwards the diagnostic message to be forwarded through the communication lines 1a to 1d, which are different from the communication lines 1a to 1d that received the diagnostic message (step S12), and terminates the processing. Summary

[0066] The onboard communication system according to the present embodiment with the above configuration has a bus network in which several ECUs 11 to 13, 21 to 23, and 31 to 33 are connected to the same communication lines (CAN buses) 1a to 1c. Several communication lines 1a to 1d provided in the vehicle 1 are connected to the gateway 5, and the gateway 5 forwards messages between the communication lines 1a to 1d. The ECUs 11 to 13, 21 to 23, and 31 to 33 included in the onboard communication system comprise ECUs 12, 13, 21 to 23, and 31 to 33, each connected to one of the communication lines 1a to 1c, and ECU 11, which is connected to both communication lines 1a and 1b. If the ECU 11 receives a diagnostic message (or broadcast) through one of the communication lines 1a and 1b, the ECU 11 forwards the diagnostic message through the other communication line 1b or 1a.

[0067] If gateway 5, to which communication lines 1a to 1d are connected, receives a diagnostic message through one of these lines, gateway 5 determines whether the diagnostic message meets a predetermined rejection condition. Gateway 5 discards the received diagnostic message without forwarding it if it determines that the rejection condition is met, and forwards the diagnostic message if it determines that the rejection condition is not met. In this way, ECU 11 can easily forward a diagnostic message by determining the rejection condition, and gateway 5 can prevent the diagnostic message from looping.

[0068] Gateway 5 compares the CAN ID and service ID contained in previously forwarded diagnostic messages with those contained in the newly received diagnostic message. As one of its rejection criteria, Gateway 5 determines that the CAN ID and service ID of two messages must match. Consequently, Gateway 5 is prevented from forwarding diagnostic messages that are likely to be identical to previously forwarded ones.

[0069] Gateway 5 determines, as one of its rejection conditions, that the communication lines 1a to 1d, which received the previously forwarded diagnostic messages, and the communication lines 1a to 1d, which receive the diagnostic message received this time, are different. If a diagnostic message with the same CAN ID and service ID is received via a different communication line 1a to 1d, it is likely that this diagnostic message is one that has been cyclically forwarded by the ECU and 11. Accordingly, it is possible to prevent such a diagnostic message from being forwarded again.

[0070] Furthermore, in the present embodiment, the message for which Gateway 5 determines whether the rejection condition is met is a broadcast message simultaneously sent to all ECUs 11 to 13, 21 to 23, and 31 to 33, and / or a diagnostic message relating to the diagnosis of vehicle 1. Such a message is very likely to be forwarded by ECU 11, to which communication lines 1a and 1b are connected, and is a message that can be repeatedly forwarded by Gateway 5 and ECU 11. Therefore, by designating these messages as the ones for which the rejection condition is determined, it is possible to prevent message loops.

[0071] Furthermore, in the on-board communication system according to the present embodiment, the communication lines 1a to 1d connected to the gateway 5 include communication line 1d, which is connected to the connector 6 for connecting and disconnecting the diagnostic device 7 to and from the vehicle 1, and the diagnostic device 7, connected to the connector 6, sends a diagnostic message. Alternatively, the ECUs 11 to 13, 21 to 23, and 31 to 33 included in the on-board communication system include the ECU 33, which has the function of performing wireless communication with the server device 8, which diagnoses the vehicle 1. The ECU 33 sends the diagnostic message received from the server device 8 to communication line 1c in the vehicle 1. The gateway 5 can prevent the diagnostic message sent by the external diagnostic device 7 or the server device 8 from being repeatedly forwarded in the network in the vehicle 1.

[0072] In the present embodiment, the messages for which Gateway 5 determines whether the rejection condition is met are diagnostic messages (or broadcasts), but the messages are not limited to this. The messages for which Gateway 5 determines whether the rejection condition is met can also be any other message, provided that the message can be forwarded by the ECU 11, to which the communication lines 1a to 1b are connected. Although it is configured to determine whether the diagnostic messages are the same or not, depending on whether the CAN ID and service ID of the diagnostic message match, the configuration is also not limited to this. Only the CAN ID or the service ID can be used to determine whether the diagnostic messages are the same.

[0073] Although the onboard communication system includes an ECU 11 connected to the two communication lines 1a and 1b, the configuration is not limited to this. It can also include three or more ECUs connected to the two communication lines. Furthermore, it can also include an ECU connected to three or more communication lines. In addition, although diagnostic device 7 and server device 8 have been identified as a single device that sends a diagnostic message, this is not the only function. Any other device can also be configured to send a diagnostic message. Diagnostic device 7 and ECU 33 can also be configured to perform wireless communication. REFERENCE MARK LIST 1 vehicle 1a to 1d Communication line 5 Gateway (On-board forwarding device) 6 connector 7 Diagnostic device 7a cable 8 Server device (diagnostic device) 11 ECU (Second on-board communication device) 12, 13, 21 to 23, 31, 32 ECU (First on-board communication device) 33 ECU (First on-board communication device) 41 processing units 41a Forwarding processing unit (forwarding processing unit for specific messages) 42 storage units 43 Communication unit 46 processing units 46a Forwarding processing unit 47 storage units 48 communication unit 49 Wireless communication unit 51 processing units 51a Rejection Conditions Determination Unit (Determination Unit) 51b Forwarding processing unit (Forwarding processing unit for specific messages) 51c Timer unit 52 storage units 52a Forwarding ID Information 52a Forwarding flag 53 Communication unit

Claims

[1] Onboard communication system, comprising: an on-board relay device (5) to which several bus communication lines (1a - 1d) mounted in a vehicle (1) are connected, for relaying messages between the communication lines (1a - 1d); several first onboard communication devices (12 - 33), each connected to exactly one of the several communication lines (1a - 1d); and a second onboard communication device (11) which is connected to at least two of the several communication lines (1a - 1d), wherein the second onboard communication device (11) includes a forwarding processing unit (41a) for specific messages for performing, if a specific message is received through one of the connected communication lines (1a - 1d), processing to send the specific message through another of the communication lines (1a - 1d), the onboard relay device (5) contains: an investigative unit (51a) to determine whether the specific message received through one of the connected communication lines (1a - 1d) meets a predetermined rejection condition; a forwarding processing unit (51b) for specific messages, which is configured not to forward the specific message if the investigation unit (51a) determines that the specific message meets the rejection condition, and to carry out processing to send the specific message through another of the communication lines (1a - 1d) if the investigation unit (51a) determines that the specific message does not meet the rejection condition; a storage unit (52) for storing identification information contained in the forwarded specific message; and a timer unit (51c) for measuring an elapsed time since the transmission of the specific message for each component of the identification information stored in the storage unit (52); wherein the investigation unit (51a) of the onboard relay device (5) is configured to determine, for each specific message containing identification information for which the elapsed time measured by the timer unit (51c) is within a predetermined time, whether identification information contained in a specific message previously sent by the relay processing unit (51b) of the onboard relay device (5) matches identification information contained in the specific message received through one of the communication lines (1a - 1d), and The forwarding processing unit (51b) for specific messages will not forward the specific message if the investigation unit (51a) determines that the identification information matches. [2] Onboard communication system according to claim 1, wherein the detection unit (51a) of the onboard forwarding device (5) is configured: to determine whether identification information contained in a specific message previously sent by the forwarding processing unit (51b) of the onboard forwarding device (5) matches identification information contained in the specific message received through one of the communication lines (1a - 1d); and to determine whether the communication line (1a - 1d) through which the preceding specific message, whose identification information matches, was received, and the communication line (1a - 1d) through which the current specific message is received are different from each other, and The forwarding processing unit (51b) is set up for specific messages, not to forward the specific message if the investigation unit (51a) determines that the identification information matches and the two communication lines (1a - 1d) are different from each other. [3] Onboard communication system according to claim 1 or 2, wherein the multiple communication lines (1a - 1d) include a communication line (1d) to which a connector (6) for connecting and disconnecting a diagnostic device (7) of the vehicle (1) is connected, and the diagnostic device connected to the connector (6) sends the specific message to the communication line (1d). [4] Onboard communication system according to any one of claims 1 to 3, wherein the several first communication devices (12 - 33) include a wireless communication device (33) for performing wireless communication with a diagnostic device (8) of the vehicle (1), and the wireless communication device (33) sends the specific message received by wireless communication from the diagnostic device (8) to the communication line (1a - 1d) of the vehicle (1). [5] Onboard relay device (5) to which several bus communication lines (1a - 1d) mounted in a vehicle (1) can be connected, for relaying messages between the communication lines (1a - 1d), wherein the onboard relay device (5) comprises: an investigative unit (51a) to determine whether the specific message received through one of the connected communication lines (1a - 1d) meets a predetermined rejection condition; a forwarding processing unit (51b) for specific messages, which is configured not to forward the specific message if the investigation unit (51a) determines that the specific message meets the rejection condition, and to carry out processing to send the specific message through another of the communication lines (1a - 1d) if the investigation unit (51a) determines that the specific message does not meet the rejection condition; a storage unit (52) for storing identification information contained in the forwarded specific message; and a timer unit (51c) for measuring an elapsed time since the transmission of the specific message for each component of the identification information stored in the storage unit (52); wherein the investigation unit (51a) of the onboard relay device (5) is configured to determine, for each specific message containing identification information for which the elapsed time measured by the timer unit (51c) is within a predetermined time, whether identification information contained in a specific message previously sent by the relay processing unit (51b) of the onboard relay device (5) matches identification information contained in the specific message received through one of the communication lines (1a - 1d), and The forwarding processing unit (51b) for specific messages will not forward the specific message if the investigation unit (51a) determines that the identification information matches. [6] Message forwarding method in which an onboard forwarding device (5) to which several bus communication lines (1a - 1d) mounted in a vehicle (1) are connected, forwards messages between the communication lines (1a - 1d), wherein the message forwarding method comprises the following steps: Storing identification information contained in a forwarded specific message; Measuring the time elapsed since the specific message was sent for each component of the stored identification information; Determine, for each specific message containing identification information for which the measured elapsed time falls within a predetermined time, whether identification information contained in a previously transmitted specific message matches identification information contained in the specific message received through one of the communication lines (1a - 1d); and Not forwarding the specific message if it is determined that the identification information matches; and Sending the specific message through another of the communication lines (1a - 1d) if it is determined that the identification information does not match.

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