JP5182269B2 - Network system - Google Patents

Description

  The present invention relates to a network system configured by interconnecting in-vehicle networks with a plurality of relay devices.

Conventionally, a network system in which two independent networks are interconnected by a plurality of relay apparatuses (gateways) is known.
In this type of network system, for example, when there are two relay devices, one relay device relays communication to an odd address destination, and the other relay device relays communication to an even address destination. If one relay device fails or the other relay device performs proxy relay, or each relay device performs broadcast communication at a certain period, the other relay devices can operate normally. It is performed to detect whether or not they are operating (for example, see Patent Document 1).

  The proxy relay, specifically, when the communication frame does not reach the communication destination terminal, causes the communication source terminal to retransmit the communication frame in which the retransmission flag is set, and the relay device sets the retransmission flag. This is realized by relaying the communication frame unconditionally regardless of whether the destination is an odd address or an even address.

Japanese Patent Laid-Open No. 10-173695

  However, in the above network system, if one relay device fails, the load on the other relay device increases, which may affect the processing of the non-failed relay device. There was a problem.

  Further, in order to retransmit the communication frame to the communication source terminal as in the above network system, it is necessary to return an acknowledge signal from the communication destination to the communication source, and such an acknowledge signal is not returned. The system also has a problem that the above-described proxy transmission cannot be applied.

  In order to solve the above-described problems, an object of the present invention is to provide a network system that can cope with a failure of one of the relay devices without increasing the load of the other relay device.

  The network system of the present invention made to achieve the above object is configured by interconnecting in-vehicle networks with a plurality of relay devices, and relay frames that need to be relayed between in-vehicle networks among communication frames. The relay frame includes at least designation information for designating a relay device through which the relay frame passes.

  Then, the relay device determines whether the relay frame needs to be relayed according to the designation information, and the communication source terminal, which is the terminal device that is the communication source of the relay frame, determines that the relay frame classified into the same type is the same relay device. The specified information is set so that it will not be routed continuously.

  In the network system of the present invention configured as described above, the relay frames classified into the same type do not pass through the same relay device continuously. Specifically, for example, there are two relay devices. When it does, it will relay alternately. For this reason, if one of the relay devices fails, the relay frame will not be continuously unreceivable for two frames or more. However, in the communication destination terminal using the relay frame, although the frame interval for receiving is coarse, The processing based on the relay frame can be continued.

As described above, according to the network system of the present invention, even when the relay device fails, normal operation can be continued without depending on special processing such as proxy transmission.
By the way, when the communication frame has a frame identifier for identifying the frame type, the relay apparatus may be configured to determine whether or not it is a relay frame based on the frame identifier.

In other words, the present invention can be suitably applied to CAN which is one of the in-vehicle networks of such a form.
In the in-vehicle network, when the transmission timing of the communication frame is set for each frame type, the relay device may be configured to determine whether the frame is a relay frame based on the transmission timing.

That is, the present invention can be suitably applied to FlexRay (registered trademark of Daimler Chrysler AG), which is one of the on-vehicle networks having such a configuration.
By the way, specifically, the following method can be considered as an example of how to allocate the relay frame using the designation information.

  That is, when there are M relay devices (M is an integer of 2 or more), each relay device is assigned one of 0, 1,..., M−1 as a distribution identifier, and the communication source terminal Sets, as the designation information, a serial number that is managed for each frame type and is incremented every time a communication frame is transmitted, and includes a value of 0 to M-1.

  Then, the relay device relays the relay frame when the remainder obtained by dividing the serial number set as the relay frame designation information by M matches the distribution identifier assigned to the relay device.

  According to the network system of the present invention configured as described above, when the number of installed relay apparatuses increases or decreases, the upper limit value of the serial number set in the communication source terminal and the distribution identifier assigned to the relay apparatus are changed as appropriate. Just a simple response.

  In the network system of the present invention, when the relay frame is set to be transmitted at a set cycle determined for each frame type, the relay device measures the elapsed time from the last relay for each frame type. Then, when the elapsed time has passed the interruption determination threshold set based on the set cycle, a preset proxy frame may be transmitted.

  According to the network system of the present invention configured as described above, when the relay frame is lost between the communication source terminal and the relay device for some reason (that is, in the in-vehicle network to which the communication source terminal is connected). In addition, since the proxy frame is transmitted, the communication destination terminal can continue the processing using the proxy frame.

  In addition, according to the network system of the present invention, by monitoring the reception state of the communication frame, the cause when the communication frame is lost is determined as follows. If there is an error, it can be narrowed down to an abnormality in the communication source network. As a result, the abnormality can be dealt with accurately and the labor required for repair can be reduced.

  Here, the proxy frame transmitted by the relay device may be set with a specified value that ensures the minimum required accuracy. For example, the relay frame is last relayed to the relay device for each frame type. The relay frame may be stored as a holding frame, and the holding frame may be transmitted as a proxy frame.

  In this case, in the communication destination terminal, the process is executed using the same value as that received in the previous relay frame, so that the process can be continued without greatly degrading the processing accuracy.

  It is desirable that the relay device includes information indicating that the proxy frame is a communication frame transmitted by proxy. Note that an area for setting the information may be prepared in advance in the relay frame, or a relay device may newly add the area. However, in the latter case, since the frame length of the relay frame changes between the communication source network and the communication destination network, the former is preferable.

  Further, it is desirable that the setting period of the relay frame is set to be equal to or less than half of the minimum necessary reception interval in order to ensure the processing accuracy required in the processing using the relay frame.

  In this case, when any one of the relay devices fails, the processing at the communication destination terminal can be continued without reducing accuracy.

The block diagram which shows the whole network system structure of embodiment. Explanatory drawing which shows the structure of the principal part of a relay frame. The flowchart which shows the content of the relay process which the microcomputer of a relay apparatus performs. Explanatory drawing which shows the relay operation at the time of normal. Explanatory drawing which shows the relay operation | movement when one relay apparatus fails. Explanatory drawing which shows the relay operation | movement when some relay frames are lost by the failure of a communication origin network.

Embodiments of the present invention will be described below with reference to the drawings.
<Overall configuration>
FIG. 1 is a block diagram illustrating an overview of a network system 1 according to the embodiment.

  As shown in FIG. 1, the network system 1 includes a plurality of electronic control units (ECUs) 20 (20a, 20b, ...) a first in-vehicle LAN (Local Area Network) 3 as an in-vehicle network, and a second in-vehicle LAN 5 as an in-vehicle network composed of a plurality of ECUs 30 (30a, 30b, ...) connected as terminal devices to the bus line L2. And a relay device 10 (10a, 10b) for interconnecting the first and second in-vehicle LANs 3, 5.

  The data communication performed via the first and second in-vehicle LANs 3 and 5 uses a CAN (“Controller Area Network” proposed by Robert Bosch, Germany) protocol generally used in the in-vehicle LAN. .

<Configuration of communication frame>
The communication frames used in the first and second in-vehicle LANs 3 and 5 are a start-of-frame indicating the start of the frame, an arbitration field indicating the priority order of the frame, a control field indicating the number of bytes of data, and the like. The CAN protocol consists of an actual data field, a CRC field to which a CRC for checking frame errors is added, an ACK field for receiving notification (ACK) from a unit that has received a correct message, and an end-of-frame indicating the end of the frame. Are well known.

Here, a relay frame that is a communication frame used when relaying via the relay device 10 will be described.
FIG. 2 shows an extracted arbitration field (hereinafter referred to as “ID region”) and data field (hereinafter referred to as “DT region”) necessary for the following description from the configuration of the relay frame.

  As shown in FIG. 2, in the ID area, an ID code (frame identifier) for identifying the message assigned to the DT area (that is, the frame type) and indicating the priority of the message is shown. Is set.

  The DT area of the relay frame includes a relay control area (CTF) for controlling relaying by the relay apparatus 10 and a transfer data area (DTF) that is a substance of data transmitted and received between ECUs.

  The CTF includes a proxy flag F indicating whether it is a normal relay frame transmitted from the ECU 20 or 30 or a proxy frame transmitted by the relay device 10 (described later), and for each frame type. A serial number SN that is managed individually and serves as identification information for identifying individual relay frames is set. In the present embodiment, the flag is composed of 1 bit, where 0 represents a normal frame and 1 represents a proxy frame. The serial number SN is composed of 7 bits, and a value of 00H to 8FH is set.

<ECU>
The ECU 20 (or 30) basically has the same configuration, and is a transceiver that sends data to the bus line L1 (or L2) and takes data from the bus line L1 (or L2). The communication circuit 21 is composed of a CAN controller that controls communication via the in-vehicle LAN 3 (or 5) according to a well-known CAN protocol, and includes a CPU, ROM, RAM, and I / O. By communicating with other ECUs, a microcomputer (microcomputer) 22 that executes various processes for realizing the functions assigned to the own ECU in cooperation with other ECUs is provided.

  Each ECU 20, 30 is assigned an ID code (transmission ID) of a message to be transmitted to another ECU and an ID code (reception ID) of a message to be received by itself, and the RAM constituting the microcomputer 22 is assigned to the RAM. An area for managing the serial number SN is prepared for each transmission ID. The serial number SN is updated (incremented) every time it is used (each time a communication frame assigned with a transmission ID corresponding to that area is transmitted).

  When transmitting the communication frame, the microcomputer 22 generates a DT region that is a main body of the message and supplies the DT region to the communication circuit 21, and executes various processes according to the contents of the DT region supplied from the communication circuit 21. To do. In particular, when the communication frame to be transmitted is a relay frame, the microcomputer 22 generates a CTF area in which the serial number SN associated with the transmission ID of the message to be transmitted is set in the DT area.

  The communication circuit 21 transmits the DT area supplied from the microcomputer 22 on the communication frame assigned with the transmission ID, receives the communication frame assigned with the reception ID, and supplies the DT area to the microcomputer 22. .

  Note that a communication interval is set for each transmission ID (frame type) in the communication frame, and it is necessary that the communication destination ECU that executes processing based on the communication frame can ensure a desired processing accuracy. The length is set to 1/2 or less of the minimum reception interval.

<Relay device>
The relay device 10 includes a communication circuit 21 and a microcomputer 13 that are configured in the same manner as the communication circuit 21 and the microcomputer 22 that constitute the ECUs 20 and 30, and a storage circuit 14 that stores the substitute frame. However, the communication circuit 11 is connected to the bus line L1, and the communication circuit 12 is connected to the bus line L2.

  An ID code (relay ID) of a communication frame that is transmitted from the ECU 20 connected to the first in-vehicle LAN 3 and needs to be relayed to the ECU 30 connected to the second in-vehicle LAN 5 is assigned to the communication circuit 11. An ID code of a communication frame that is transmitted from the ECU 30 connected to the second in-vehicle LAN 5 and needs to be relayed to the ECU 20 connected to the first in-vehicle LAN 3 is assigned to the circuit 12. The communication frame having a transmission ID that matches the ID code (relay ID) assigned to the communication circuits 11 and 12 is set to be taken in as a relay frame.

  The storage circuit 14 is provided with an area for storing at least one communication frame for each relay ID. Hereinafter, the communication frame stored in the storage circuit 14 is referred to as a holding frame. Further, the microcomputer 13 is provided with an elapsed timer indicating the elapsed time from the last relay for each relay ID, and has a disconnection determination threshold value for determining whether or not reception of the relay frame is interrupted. Is set.

  For example, the interruption determination threshold value may be a value obtained by adding a permissible delay time set based on system characteristics or the like to a communication interval set for a target communication frame (relay frame).

  Also, each relay apparatus 10 is assigned a distribution identifier used for distribution of relay frames that share the relay. In this embodiment, the distribution identifier of the relay apparatus 10a is 1, and the distribution identifier of the relay apparatus 10b is assigned. The identifier is set to 0.

<Relay processing>
Here, the contents of the relay process executed by the microcomputer 13 of the relay apparatus 10 will be described with reference to the flowchart shown in FIG. This process starts when the relay apparatus 10 is powered on. In parallel with this process, at least a process of updating (incrementing) the elapsed timer provided for each relay ID at a certain time is executed.

  When this processing is started, first, in S110, all elapsed timers are initialized by clearing them to zero, and in S120, it is determined whether or not the communication circuits 11 and 12 have captured the relay frame, and the relay frame is captured. Advances to S130.

  In S130, it is determined whether or not relaying should be executed with reference to the serial number SN set in the fetched relay frame. Here, the LSB of the identification information (that is, the remainder obtained by dividing the identification information by the number 2 of the relay devices 10) is compared with the distribution identifier assigned to the relay device 10, and if both match, the relay is performed. Judge that it should be done.

  If it is determined in S130 that the relay should be executed, the process proceeds to S140, and the communication circuit 11 or 12 is configured such that the side that has taken in the relay frame is the reception side communication circuit and the other side is the transmission side communication circuit. The relay frame taken in by the communication circuit is transmitted to the transmission side communication circuit.

  In S150, the holding frame stored in the storage circuit 14 is updated with the transmitted relay frame. In S160, an elapsed timer related to relay is initialized, and the process returns to S120.

  If it is determined in the previous S120 that the relay frame has not been captured, or if it is determined in the previous S130 that the relay should not be executed, the process proceeds to S170. However, when shifting from S130 to S170, the fetched relay frame is discarded as it is.

In S170, it is determined whether or not there is an elapsed timer (hereinafter referred to as “time excess timer”) exceeding the interruption determination threshold value. If not, the process returns to S120.
If it is determined in S170 that there is an overtime timer, the process proceeds to S180, where the relay ID holding frame associated with the overtime timer is transmitted to the transmission side communication circuit as a proxy frame, and in S190, Then, the elapsed timer for proxy transmission is initialized and the process returns to S120.

<Operation>
Next, the relay operation of the communication frame by the network system 1 will be described. However, the basic transmission / reception operation of the communication frame on each of the in-vehicle LANs 3 and 5 is a well-known that performs non-destructive arbitration in bit units using the ID area. Since it is executed in accordance with the CAN protocol, its description is omitted here.

Here, FIG. 4 is an explanatory diagram showing the relay operation of the communication frame at the normal time.
Note that one ECU 30 connected to the second in-vehicle LAN 5 is ECU 1, one ECU 20 connected to the first in-vehicle LAN 3 is ECU 2, and two relay devices 10 (10a, 10b) are GW1 (distribution identifier = 1). ), GW2 (distribution identifier = 0), the transmission ID of ECU1, the reception ID of ECU2, and the relay ID of GW1 and GW2 each include at least ID = 002H. That is, a case where the communication frame set to ID = 002H transmitted from the ECU 1 is received by the ECU 2 via the GW 1 and GW 2 will be described.

  As shown in FIG. 4, the ECU 1 transmits a communication frame with an ID set to 002H at regular communication intervals while sequentially incrementing the serial number SN. At this time, since the proxy flag is set to F = 0, every time a communication frame is transmitted, the set CTF value changes as 00H, 01H, 02H,.

  A communication frame in which the LSB of the CTF is set to 0 (that is, the serial number SN is an even number) is via GW2, and a communication frame in which the LSB of the CTF is set to 1 (the serial number SN is an odd number) is via GW1. And relayed from the second in-vehicle LAN 5 to the first in-vehicle LAN 3.

  That is, GW1 and GW2 relay the communication frame with the ID set to 002H alternately, and the ECU 2 receives the communication frame with the ID set to 002H without omission.

Next, FIG. 5 is an explanatory diagram showing an operation when the GW 2 fails.
As shown in FIG. 5, the ECU 2 receives only the communication frame relayed via the GW 1. In other words, the communication frame is received at a cycle that is twice as long as the normal communication interval, but the communication interval is originally transmitted at a minimum half cycle that can ensure the required processing accuracy. Even if the cycle is doubled, the required processing accuracy is ensured in the ECU 2.

Next, FIG. 6 is an explanatory diagram showing an operation when a part of communication frames cannot be received by the GW 1 and the GW 2 due to a failure in the second in-vehicle LAN 5.
As shown in FIG. 6, it is assumed that the communication frame in which the serial numbers SN are set to 03H and 04H is affected by the failure. Since the GW 1 cannot confirm the communication frame with the serial number SN of 03H, when the elapsed timer initialized at the previous relay (relay of the communication frame with the serial number SN of 01H) reaches the interruption determination threshold, the holding frame (That is, the previous relay frame) is transmitted as a proxy frame.

  On the other hand, in GW2, since the communication frame with the serial number SN of 04H cannot be confirmed, when the elapsed timer initialized at the previous relay (relay of the communication frame with the serial number SN of 02H) reaches the disruption determination threshold, The holding frame (that is, the previous relay frame) is transmitted as a proxy frame.

  When the proxy frame is transmitted by GW1 and GW2, since the CTF proxy flag F is set to 1, the value of CTF is not the serial number SN itself but a value obtained by adding 80H to the serial number SN.

After that, when recovering from the failure, normal operation is performed.
As a result, the ECU 2 cannot receive the communication frame with the serial number SN of 03H and 04H. Instead, the proxy flag F is set to 1 and the serial number SN is 01H and 02H (that is, the CTF is 81H, 82H) will be received.

<Effect>
As described above, in the network system 1, two in-vehicle LANs 3 and 5 are connected by the two relay devices 10a and 10b, and the relay frame having the same ID code (frame type) is the two relay devices 10a and 10b. It is set to be relayed alternately.

  Therefore, according to the network system 1, when one of the relay devices 10 fails, the reception interval of the relay frame having the same ID code is doubled, but the reception of the relay frame having the specific ID code is not performed. Since there is no interruption, processing based on the relay frame can be continued.

  Moreover, according to the network system 1, a communication cycle is set for each ID code, and the communication cycle is set to ½ of the reception cycle necessary for ensuring the desired processing accuracy in the receiving ECUs 20 and 30. Therefore, even if the reception interval of the relay frame is doubled due to the failure of the relay device 10, it is possible to ensure the minimum processing accuracy required for the processing.

  That is, according to the network system 1, when an abnormality occurs in any one of the relay devices 10, the relay devices 10 can sufficiently cope without monitoring each other's operation state. The configuration of the relay device 10 can be simplified.

  Further, in the network system 1, the relay device 10 includes an elapsed timer that measures the elapsed time from the previous relay for each relay frame ID code (relay ID), and when the elapsed timer reaches the disruption determination threshold, the proxy It is supposed to send frames.

  Therefore, according to the network system 1, by monitoring the reception state of the relay frame, when the relay frame is lost, if there is no reception of the proxy frame, there is an abnormality in the relay device 10 and there is reception of the proxy frame. The cause of the abnormality can be narrowed down as a communication source network abnormality, and as a result, the abnormality can be dealt with accurately and the labor required for repair can be reduced.

  In the network system 1, the serial number SN is assigned to the relay frame, the distribution identifier is assigned to the relay device 10, and whether the value obtained by dividing the serial number SN by the number of the relay devices 10 matches the distribution identifier. Depending on how the relay frames are distributed.

Therefore, according to the network system 1, when the number of the relay devices 10 is changed, the upper limit value of the serial number SN set by the ECUs 20 and 30 (set to (integer multiple of the number of relay devices 10) -1), This can be handled easily by simply changing the distribution identifier assigned to each relay apparatus 10 as appropriate.
[Other Embodiments]
Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and can be implemented in various modes without departing from the gist of the present invention.

  For example, in the above-described embodiment, the relay frame is temporarily captured by the communication circuits 11 and 12 of the relay device 10 and then the serial number SN is confirmed to determine whether or not the relay should be performed. 12 may be configured so that the serial number SN can be referred to, and only when the ID code matches the relay ID and the serial number SN is to be relayed, the communication frame may be captured.

  In the above embodiment, the proxy flag F area is secured in the relay control area CTF prepared in advance in the relay frame. However, the relay apparatus 10 may be configured to newly add the proxy flag F area. Good.

However, in this case, since the data length varies between the communication source of the relay frame, the communication SS vacant source, and the relay destination, it is more preferable that an area is secured in advance in the transmission frame serving as the relay source.
In the above embodiment, the relay device 10 has a function of transmitting a proxy frame, but this function may be omitted.

  In the above embodiment, the holding frame (that is, the previous relay frame) is used as the proxy frame. However, a fixed value that ensures the minimum necessary processing accuracy at the time of failure is used in advance for each relay ID. A fixed frame that has been set may be used.

  In the above embodiment, the relay frame is distributed to the two relay devices 10 using the serial number SN. However, in the ECUs 20 and 30 that transmit the relay frame, a distribution identifier (serial number) is used instead of the serial number SN. (It is not necessary to be present).

In the above embodiment, the CAN is used as the in-vehicle LANs 3 and 5, but is not limited thereto, and for example, FlexRay (registered trademark of Daimler Chrysler AG) may be used.
In this case, the ECUs 20 and 30 transmit the communication frame using the transmission timing (segment) assigned for each frame type (message content), and the relay device 10 determines whether or not it is a relay frame depending on the transmission timing. What is necessary is just to comprise so that it may be judged.

  However, when the frame type and the transmission timing are not uniquely associated as described above, an ID area for setting the ID code is provided in the data area in the same manner as the relay control area CTF, and the relay apparatus 10 It may be configured to determine whether the frame is a relay frame by referring to the ID area.

  DESCRIPTION OF SYMBOLS 1 ... Network system 3, 5 ... Car-mounted LAN 10 ... Relay apparatus 11, 12, 21 ... Communication circuit 13, 22 ... Microcomputer (microcomputer) 14 ... Memory circuit 20, 30 ... ECU L1, L2 ... Bus line

Claims (8)

A network system configured by interconnecting in-vehicle networks with a plurality of relay devices,
Among the communication frames, those that need to be relayed between the in-vehicle networks are used as relay frames, and the relay frames include at least designation information for designating the relay device to be relayed at the time of relaying,
The relay device determines whether the relay frame needs to be relayed according to the designation information;
The communication source terminal, which is a terminal device serving as a communication source of the relay frame, sets the designation information so that the relay frames classified into the same type do not pass through the same relay device continuously. A network system characterized by The communication frame has a frame identifier for identifying a frame type,
The network system according to claim 1, wherein the relay apparatus determines whether the relay frame is the relay frame based on the frame identifier. In the in-vehicle network, the transmission timing of the communication frame is set for each frame type,
The network system according to claim 1, wherein the relay device determines whether the relay frame is based on the transmission timing. There are M relay devices (M is an integer equal to or greater than 2), and each of the relay devices is assigned any one of 0, 1,..., M−1 as a distribution identifier,
The communication source terminal sets, as the designation information, a serial number that is managed for each frame type and that is incremented every time the communication frame is transmitted, and includes a value of 0 to M−1.
The relay device relays the relay frame when the remainder obtained by dividing the serial number set as the designation information of the relay frame by M matches the distribution identifier assigned to the relay device. The network system according to claim 1, wherein the network system is performed. The relay frame is transmitted at a set cycle determined for each frame type,
The relay device measures the elapsed time from the last relay for each frame type, and when the elapsed time has passed the interruption determination threshold set based on the set cycle, The network system according to any one of claims 1 to 4, wherein a frame is transmitted.   The network system according to claim 5, wherein the relay device stores the relay frame relayed last as a retained frame for each frame type and transmits the retained frame as the proxy frame. .   The network system according to claim 5 or 6, wherein the relay device includes information indicating that the proxy frame is a communication frame transmitted by proxy.   6. The setting period of the relay frame is set to a half or less of a minimum reception interval required to ensure processing accuracy required in processing using the relay frame. The network system according to claim 7.

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