JP5147533B2 - Relay device and relay method - Google Patents

Description

  The present invention relates to a relay device that relays data transmitted from communication devices connected to a plurality of different communication networks to other communication devices. In particular, when transmitting data based on the priority assigned to each data, a relay device capable of relaying data more efficiently so that there is no significant difference in delay time with extremely high and low priority, and It relates to the relay method.

  In recent years, systems that connect a plurality of communication devices, assign functions to the communication devices, exchange data with each other, and perform various processes in cooperation have been used in various fields. For example, in the field of an in-vehicle LAN (Local Area Network) arranged in a vehicle, an ECU (Electronic Control Unit) is used as a communication device, and each ECU performs a specialized process to exchange data with each other. By exchanging, various functions are realized as a system.

  As the functions of each communication device are specialized and the functions that can be performed by each communication device increase, the number and types of communication devices connected to the communication line also increase. Furthermore, since various functions are expected as a system, it is necessary for each communication apparatus to share data and cooperate, and the amount of data transmitted and received increases.

  An increase in the amount of data transmitted and received on the communication line causes data delay or loss due to collision. A significant delay or loss of data may be fatal to driving assistance functions such as brake control by the ECU.

  Therefore, a configuration in which the communication lines are divided into a plurality of parts and the ECUs are connected to different communication lines is common. This is because by combining ECUs that use data in common, waste of use of the communication line can be suppressed and delay can be suppressed. In addition, in order to efficiently use communication lines in response to an increase in the type of ECU, there is a configuration in which the ECUs are connected to communication lines having different communication speeds by separating the ECUs according to the type of data to be transmitted and received. In these configurations, different communication lines are connected by a relay device that controls transmission and reception of data.

  Patent Document 1 discloses a configuration in which ECUs are divided into a plurality of groups and connected to communication lines for each group, and different communication lines are connected by a relay device. In the technique disclosed in Patent Document 1, priority information for identifying priority is added to data to be transmitted and received. When the relay device transmits / receives data between different communication lines, the priority is determined from the priority information of the received data, and data with high priority is transmitted preferentially, and the communication load of the communication line increases. However, a technique for preventing transmission of high-priority data from being greatly delayed is disclosed.

On the other hand, Patent Document 2 discloses a technique for determining a transmission order so that data having a standby time equal to or longer than a predetermined time is transmitted early even if the data has low priority.
JP 2005-159568 A JP-A-6-30472

  With the technique disclosed in Patent Document 1, it is possible to avoid a large delay in data with high priority. However, when priority is given to transmission of data with high priority, transmission of data with low priority is delayed. If the success rate of data transmission with low priority is not high, there is a possibility that the transmission order will be later and the data will stay in the relay apparatus.

  With the technique disclosed in Patent Document 2, data with a longer waiting time can be transmitted earlier. However, it is desired to realize a relay device that can relay efficiently with a simpler configuration than measuring the waiting time of each data so that the priority is high and the delay time is not significantly different.

  The present invention has been made in view of such circumstances, and when the relay apparatus fails to transmit the data received via the communication line, the data is returned and the number of times of return is limited. It is an object of the present invention to provide a relay device and a relay method capable of relaying data more efficiently so that the delay time does not differ extremely between the heights of the two.

The relay device according to the first aspect of the present invention is connected to a plurality of communication lines, and transmits data transmitted with priority given from the external devices connected to the respective communication lines to other external devices. Te in the relay apparatus for relaying data, receiving means for receiving data transmitted from the external apparatus, storage means for storing in the order received data said receiving means has received, the data being memorize in the storage means based on the order, and transmission control means for determining the order in which Ru trying to send to extract the data, and transmitting means for attempting transmission of data based on the order in which the transmission control unit is determined, the transmission of data by said transmitting means In the case where the data fails, a means for returning the data to the storage means and a means for counting the number of times the data is returned in association with the data each time the data is returned by the means. When sending Ri, when the number associated with the said data is equal to or greater than a predetermined number of times, characterized in that you have to attempt to send until the transmission is successful.

  In the relay apparatus according to the second invention, when transmission of data by the transmission unit fails and the data is returned to the storage unit, it is stored again at the head of the data stored in the storage unit. It is characterized by.

  The relay apparatus according to a third aspect is characterized in that the data is returned to the storage means when the transmission of data by the transmission means fails continuously for a predetermined number of times or more.

  The relay apparatus according to a fourth aspect is characterized in that the transmission control means preferentially extracts and transmits the assigned high priority data.

  A relay device according to a fifth aspect of the present invention comprises means for storing a table in which priority data to be transmitted with priority and non-priority data are distinguished, and the transmission control means has priority stored in the table Data is extracted and transmitted preferentially.

A relay method according to a sixth aspect of the present invention is a method in which a relay device connected to a plurality of communication lines and connected to an external device via each of the communication lines is transmitted with priority given from the external device. the a method for relaying data transmitted to other external device, receives data transmitted from the external device, and stored in the buffer the received data in the received order, the order of the data that has been memorize in said buffer wherein to determine the order in which Ru trying to extract and send data from the buffer based, based on the determined order attempts to send data, if it fails to transmit the data, returning the data to the buffer, the number of returned Counting and data whose number is equal to or greater than a predetermined number are tried to be transmitted until transmission is successful.

In the first invention and the sixth invention, connected to a plurality of communication lines, a relay device for relaying data between the external device connected via a respective communication line, and stores the data in the order of reception, and remembers Based on the order of certain data, the order in which data is extracted and transmitted is determined and transmission is attempted. If the data transmission fails, the relay device returns the data to the storage means for storing the received data, and attempts to transmit other data in the next order stored in the storage means. Therefore, it is avoided that transmission of other data having a high possibility of successful transmission is delayed, and data received by the relay device is prevented from staying until transmission of one data is successful. Can do. The relay device counts the number of times each time data transmission fails and data is returned to the storage means. The relay device attempts to transmit data until the data returned a predetermined number of times or more is successfully transmitted. As a result, data having a relatively low priority is transmitted to another external device without an extremely long delay time.

  In the second invention, when the relay apparatus fails to transmit data and returns the data to the storage means, the data is stored again at the head of the data stored in the storage means. As a result, since transmission is attempted with priority extracted at the next transmission opportunity, it is possible to avoid an extremely long delay time of data having a relatively low priority.

  In the third invention, the number of failures when the relay device fails to transmit data and sends the data back to the storage means is set. That is, the data is returned to the storage means for the first time when data transmission has failed continuously for a predetermined number of times. As a result, even in a situation where the priority is relatively low and other data is preferentially transmitted, it is possible to avoid an extremely long delay time by increasing data transmission opportunities.

  In the fourth invention, the relay device preferentially extracts data having a higher priority when extracting data from the storage means. Thereby, when returning the data which failed in transmission to a memory | storage means and trying transmission of other data, data with high possibility that transmission will be successful are transmitted first. When transmission of one data has failed, a transmission opportunity is given to other data, but when the transmission of the other data further fails, it is assumed that the data delay time will become longer overall. Is done. On the other hand, in the present invention, data with high possibility of successful transmission is preferentially transmitted, so that data can be efficiently relayed as a whole.

  In the fifth invention, the relay device stores a table in which priority data and non-priority data are distinguished. Regardless of the assigned priority, the transmission order can be controlled more flexibly based on the priority of data with reference to the table, and data can be efficiently relayed as a whole.

  According to the present invention, it is possible to avoid the data from continuing to stay in the relay device, and if the priority is relatively low and the data whose transmission order is later is large, the transmission is continued until the transmission is successful. Tried. As a result, the delay time of data with low priority is prevented from becoming extremely long, and data can be efficiently relayed so that there is no significant difference in delay time with high or low priority.

  Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof.

  In the embodiment described below, a case where the present invention is applied to a relay device configuring an in-vehicle network will be described as an example.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of an in-vehicle network in the first embodiment. The in-vehicle network includes ECUs (Electronic Control Units) 1a, 1a,..., 1b, 1b,..., Which are communication devices for transmitting and receiving data, and communication lines 2a, 1a, 1a,. 2b and the different communication lines 2a and 2b, and a relay device 3 that relays data transmission / reception between the ECUs 1a, 1a,... And the ECUs 1b, 1b,.

  ECUs 1a, 1a,... Are connected to the communication line 2a in a bus type, and ECUs 1b, 1b,... Are connected to the communication line 2b in a bus type, and transmit and receive data according to the CAN protocol. The relay device 3 is also connected in a bus shape to both the communication line 2a and the communication line 2b.

  The ECUs 1a, 1a,..., 1b, 1b,... Are devices that can transmit data including numerical information of various physical quantities such as measured values, calculated values, and control values, or can be controlled by a microcomputer such as an engine or a brake. For example, the ECU 1a functions as an ABS (Antilock Brake System) and is connected to a sensor (not shown) that detects the rotational speed (wheel speed) of the wheel. ECU1a controls a brake based on the wheel speed detected via the sensor at the time of braking of a vehicle, and transmits the measured value of wheel speed to each apparatus connected to the communication line 2a as data.

  In addition, transmission / reception of data between ECU1a, 1a, ..., 1b, 1b, ... and the relay apparatus 3 is performed by transmission / reception of the "message (frame)" in which several data were put together. The message is transmitted including a message ID (CAN ID) defined for each combination of a plurality of data in the header portion. The ECUs 1a, 1a,..., 1b, 1b,... Collectively transmit data groups obtained by their own operations as messages.

  The relay device 3 includes a CPU (Central Processing Unit) 30 that controls the operation of each component, a ROM 31 that uses a nonvolatile memory such as a flash memory, an EPROM (Erasable Programmable Read Only Memory), and an EEPROM (Electrically EPROM), A RAM 32 using a memory such as a DRAM (Dynamic Random Access Memory) or an SRAM (Static Random Access Memory), a CAN controller 33 using a network controller compliant with the CAN protocol, and an internal bus 34 are provided. The CPU 30, ROM 31, RAM 32, and CAN controller 33 are all connected to the internal bus 34 and can communicate with each other. The CPU 30, ROM 31, RAM 32, CAN controller 33, and internal bus 34 may constitute a microcomputer.

  The CPU 30 receives power supply from a power supply device such as a vehicle alternator and a battery (not shown), reads various information from the ROM 31 to the RAM 32, controls the CAN controller 33, and transmits and receives messages.

  The ROM 31 stores a control program that is read and executed by the CPU 30. Further, a relay ID table 35 referred to by the CPU 30 is stored. Details of the relay ID table 35 will be described later.

  The RAM 32 temporarily stores information generated in the process of the CPU 30 or measurement values represented by signals input from sensors (not shown).

  The CAN controller 33 includes a communication control unit 36, a buffer 37, a first transmission / reception unit 38, and a second transmission / reception unit 39, and realizes communication via the communication lines 2a and 2b according to the CAN protocol.

  When the first control unit 38 or the second transmission / reception unit 39 receives a message, the communication control unit 36 notifies the CPU 30 of this message. The communication control unit 36 stores the received messages in the buffer 37 in the order of reception. The communication control unit 36 relays a message based on an instruction from the CPU 30. Specifically, the communication control unit 36 extracts a message stored in the buffer 37 based on an instruction from the CPU 30, and the communication line 2a to which the relay destination ECUs 1a, 1a,..., 1b, 1b,. , 2b, the extracted message is delivered to the first transmission / reception unit 38 or the second transmission / reception unit 39 to be transmitted. That is, the order in which transmission is attempted is determined in the order in which the communication control unit 36 extracts messages.

  The buffer 37 uses a RAM such as an SRAM or a DRAM to temporarily store the received message. The buffer 37 is also used as a transmission queue that stores messages to be relayed for transmission waiting. The transmission queue is associated with each of the first transmission / reception unit 38 and the second transmission / reception unit 39, and indicates whether the message is stored for transmission from the first transmission / reception unit 38 or the second transmission / reception unit 39. It is possible to distinguish. If the storage capacity of the buffer 37 is small and a plurality of messages cannot be stored in association with the first transmission / reception unit 38 and the second transmission / reception unit 39, a storage area used as a transmission queue is secured in the RAM 32. In this case, the CPU 30 distinguishes a plurality of queues corresponding to each of the plurality of transmission / reception units, extracts a message to be transmitted by the corresponding transmission / reception unit from each queue, and passes the message to the communication control unit 36. And

  The first transmission / reception unit 38 and the second transmission / reception unit 39 include a filter circuit, an AD conversion circuit, and the like, and realize transmission / reception of messages by detecting and outputting a differential voltage in the communication lines 2a and 2b. The communication control unit 36 monitors the communication status on the communication lines 2a and 2b by the first transmission / reception unit 38 and the second transmission / reception unit 39, determines whether or not the communication control unit 36 can transmit a message, and the transmission is performed. Send messages when possible. Specifically, the communication control part 36 can transmit a message by the 1st transmission / reception part 38, while ECU1a, 1a, ... connected to the communication line 2a is not transmitting a message. On the other hand, while the ECUs 1a, 1a,... Connected to the communication line 2a are transmitting messages, the communication control unit 36 receives the transmitted message by the first transmission / reception unit 38. When data transmission is started simultaneously from any one of the ECUs 1a, 1a,... And the relay device 3 connected to the communication line 2a, one of them transmits a message preferentially by arbitration based on the CAN protocol. It is. Specifically, priority / non-priority of a message is determined as follows. Messages are transmitted and received by digital signals represented by 0 (zero) bits and 1 bit. A message ID included in the header of the message is used as an arbitration field, and arbitration is performed on the communication line 2a by a bit string in the arbitration field. In the CAN protocol, priority is given to sending messages with an arbitration field that lasts longer than zero (zero) bits. That is, when the message ID is interpreted as a numerical value, the priority of a message with a smaller numerical value is high. The ECU 1a that transmits the priority message or the relay device 3a wins the arbitration. The communication control unit 36 can continue transmission by the first transmission / reception unit 38 only when the arbitration in the communication line 2a is won. When the communication control unit 36 loses arbitration, the communication control unit 36 stops transmission by the first transmission / reception unit 38, switches to reception of a message transmitted from the ECU 1a that continues other transmissions, and receives the message simultaneously with the other ECUs 1a.

  The CPU 30 appropriately stores the message received by the first transmission / reception unit 38 or the second transmission / reception unit 39 of the CAN controller 33 in the transmission queue of the buffer 37 by the communication control unit 36 based on the relay ID table 35 stored in the ROM 31. Message relaying is realized.

  FIG. 2 is an explanatory diagram showing an example of the contents of the relay ID table 35 stored in the ROM 31 of the relay device 3. In the relay ID table 35, messages are stored separately by message ID. In addition, communication lines 2a, 2b to which the ECUs 1a, 1a,..., 1b, 1b,... That are message senders are connected, and communications to which the ECUs 1a, 1a, ..., 1b, 1b,. Information for distinguishing the lines 2a and 2b is stored in association with the message ID. Specifically, “0” represents the communication line 2a to which the first transmission / reception unit 38 is connected, and “1” represents the communication line 2b to which the second transmission / reception unit 39 is connected. Furthermore, a priority different from the priority determined by the message ID of each message is stored in association with the message ID. Specifically, “1” represents a message to be transmitted with priority, and “0” represents a non-priority message. The priority is represented by a natural number larger than “1”, “1” is the highest priority, the higher the numerical value, the lower the priority, and “0” is a non-priority message. It is good also as a structure to represent.

  In the content example of the explanatory diagram of FIG. 2, the message with the message ID “100” is connected to the communication line 2a with any one of the ECUs 1b, 1b,... Connected to the communication line 2b as a transmission source. Any one of the ECUs 1a, 1a,. A message whose message ID is “100” is a message to be transmitted with priority. Similarly, a message whose message ID is “500” is sent from any of the ECUs 1a, 1a,... Connected to the communication line 2a, and any of the ECUs 1b, 1b,. Is the relay destination. A message with a message ID “500” is a non-priority message.

  When the CPU 30 detects that the message has been received from the first transmission / reception unit 38 by the notification from the communication control unit 36, the CPU 30 refers to the relay ID table 35 of the ROM 31 and determines the relay destination ECU 1b based on the message ID of the received message. , 1b,... Are specified. Then, the CPU 30 stores the message in the transmission queue for the second transmitting / receiving unit 39 of the buffer 37 so that the message is transmitted from the second transmitting / receiving unit 39 connected to the specified communication line 2b by the communication control unit 36. To do. The CPU 30 determines that there is no need to relay a message that is not stored in the relay ID table 35, such as a message used only by the ECUs 1a, 1a,... Connected to the communication line 2a. May be discarded.

  Further, when the CPU 30 detects that the message has been received from the first transmission / reception unit 38 by the notification from the communication control unit 36, the CPU 30 refers to the relay ID table 35 of the ROM 31 and determines the message based on the message ID of the received message. The priority is recognized and notified to the communication control unit 36. As a result, processing such as storing a message having a high priority at the head of the transmission queue by the communication control unit 36 can be performed. In this way, by setting and storing a priority different from the priority determined by the message ID for each message in the relay ID table 35, the transmission order can be flexibly set according to the priority not depending on the message ID. Can be controlled.

  FIG. 3 is an explanatory diagram showing an outline of message relay processing by the CAN controller 33 of the relay device 3 according to the first embodiment. FIG. 3 conceptually shows processing when the second transmitter / receiver 39 relays a message received by the first transmitter / receiver 38 from the ECUs 1a, 1a,... Connected to the communication line 2a. In FIG. 3, the first transmission / reception unit 38, the buffer 37, and the second transmission / reception unit 39 are shown side by side along the flow of transmission / reception. The case where the communication control unit 36 transmits the message received by the second transmission / reception unit 39 by the second transmission / reception unit 38 is the same as the case of transmission by the second transmission / reception unit 39 described above.

  In the first embodiment, the transmission queue for the second transmission / reception unit 39 secured in the buffer 37 is composed of two queues, a first queue and a second queue. Note that the number of queues is not limited to two. Each queue is used based on FIFO (First In First Out), and messages are stored in the queue in the order of reception with the right side of the figure as the head, and the messages are extracted from the head.

  The communication control unit 36 distributes and stores the messages received by the first transmission / reception unit 38 into the first queue and the second queue. The communication control unit 36 stores, in the first queue, a message having a relatively high priority value whose message ID value is a predetermined value (for example, “600”) or less, and has a relatively low priority value that exceeds the predetermined value. Messages are stored in the second queue and distributed. Alternatively, the received message storage instruction from the CPU 30 referring to the relay ID table 35 of the ROM 31 includes information on the priority (“0” or “1”), and the message having the priority “1”. May be processed by the communication control unit 36 so as to be stored in the first queue. Further, when the third and fourth queues are secured in the buffer 37, the communication control unit 36 determines that the message with the priority “1” is the first queue, the priority based on the priority information from the CPU 30. For example, a message with “2” is assigned to the second queue, a message with the priority “3” is assigned to the third queue, and a message with the priority “0” is assigned to the fourth queue. Good.

  Then, the communication control unit 36 extracts a message from the first queue and the second queue alternately or according to the priority, and gives the message to the second transmission / reception unit 39 to be transmitted from the second transmission / reception unit 39. When extracting the message from the first queue and the second queue, the communication control unit 36 may extract the message from either the first queue or the second queue at a preset ratio. For example, the communication control unit 36 extracts messages from the first queue and the second queue at a ratio of 2: 1. That is, the communication control unit 36 extracts one message from the second queue after extracting two messages successively from the first queue, and then extracts two messages from the first queue again. In the relay device 3, the communication control unit 36 extracts messages from a plurality of queues secured in the buffer 37 (for example, extracts from two queues at an X: Y ratio, and from three queues X: Y). : Extracted at a ratio of Z, etc.) can be appropriately set by a configuration such as rewriting a setting file written in the ROM 31 or RAM 32. In addition, when the communication control unit 36 performs message extraction according to priority, the communication control unit 36 selects a message having a higher priority from among the messages stored at the heads of the first queue and the second queue. Extract first. The second transmission / reception unit 39 has a built-in memory for one message, and transmits a message stored in the memory at a transmittable timing. The communication control unit 36 passes the extracted message to the memory of the second transmission / reception unit 39.

  The communication control unit 36 of the CAN controller 33 according to the first embodiment holds the message in the memory of the second transmission / reception unit 39 until it wins the arbitration when the second transmission / reception unit 39 starts transmission of the message and loses arbitration. Without processing, the process of temporarily returning to the transmission queue of the buffer 37 is performed. Below, the transmission control process by the CAN controller 33 is demonstrated with reference to a flowchart.

  FIG. 4 is a flowchart illustrating an example of a processing procedure in which the relay device 3 according to the first embodiment transmits a message using the CAN controller 33. The processing procedure described below shows a case where a message is transmitted by the second transmission / reception unit 39.

  In response to a transmission instruction from the CPU 30, the communication control unit 36 extracts a message from the transmission queue of the buffer 37 corresponding to the second transmission / reception unit 39 (step S1). The communication control unit 36 alternately extracts the first message in each of the first queue and the second queue.

  The second transmission / reception unit 39 starts transmission of the message by passing the transmission of the message extracted by the communication control unit 36 based on the instruction of the CPU 30 to the memory of the second transmission / reception unit 39 (step S2). The communication control unit 36 monitors the communication status on the communication line 2b by the second transmission / reception unit 39 and determines whether or not the arbitration has been won (step S3).

  If the communication control unit 36 determines that the arbitration has been won (S3: YES), it continues to transmit the extracted message (step S4), completes the transmission, and ends the process. The CPU 30 detects that the transmission has been completed by a notification from the communication control unit 36. The CPU 30 executes the process from step S1 again to transmit the next message by the communication control unit 36.

  When it is determined that the communication control unit 36 has lost the arbitration (S3: NO), the CPU 30 detects that the transmission has failed due to a notification from the communication control unit 36, and the number of times the message that has been transmitted is returned is a predetermined number (for example, 3 times) or more (step S5). If the communication control unit 36 determines that the number of return times is less than the predetermined number (S5: NO), it extracts the next message from the head of the transmission queue (first queue or second queue) (step S6), and step The message for which transmission was attempted in S2 is returned to the transmission queue (step S7). At this time, the communication control unit 36 stores the message again at the head of the transmission queue.

  Next, the communication control unit 36 adds the number of return times associated with the returned message (step S8), returns the process to step S2, and starts transmitting the message extracted in step S6 (S2). The processes from S3 to step S8 are repeated. In step S8, the CPU 30 may receive a notification of return from the communication control unit 36 and store the number of return in association with the message in the RAM 32, or store the number of return in a memory (not shown) built in the communication control unit 36. You may make it do.

  The communication control unit 36 extracts the message sent back to the head of the transmission queue (S1), starts transmission of the message (S2), and determines that it has lost the arbitration (S3: NO), and sends it back. When it is determined that the number of times is equal to or greater than the predetermined number (S5: YES), the process returns to step S2. That is, the communication control unit 36 does not send back a message that has been returned more than a predetermined number of times, and tries to transmit a message until arbitration is won.

  As a result, it is possible to avoid delaying transmission of other messages due to low-priority messages that have a high possibility of losing arbitration and stay in the memory of the second transmission / reception unit 39. In addition, when the number of return times is equal to or greater than the predetermined number, even if other messages are waiting in the transmission queue, the delay time of a low-priority message becomes extremely long by attempting transmission until the transmission is successful. You can avoid that.

  The case where the communication control unit 36 transmits a message by the first transmission / reception unit 38 is the same as the processing procedure shown in the flowchart of FIG.

  FIG. 5 is an explanatory diagram illustrating an example of the order of messages relayed by the relay device 3 according to the first embodiment. 5 shows an example in which a message received by the first transmitter / receiver 38 is transmitted from the second transmitter / receiver 39 and relayed to the ECUs 1b, 1b,. As shown in the explanatory diagram of FIG. 5, messages with message IDs “500”, “400”, “300”, “200”, “100”, and “900” received by the first transmission / reception unit 38 at a certain point in time. Are already stored in the transmission queue of the buffer 37 in the order of reception. In addition, while the second transmission / reception unit 39 transmits a message, the first transmission / reception unit 38 newly receives messages with message IDs “800” and “700”.

  In the explanatory diagram shown in FIG. 5, the order of messages to be transmitted by the second transmitter / receiver 39 is shown below the block of the second transmitter / receiver 39. Message transmission is attempted in order from the top to the bottom, and the message with the message ID described in parentheses is returned. In addition, the order of messages actually transmitted by the second transmission / reception unit 39 is shown outside the block of the relay device 3. This also shows that messages were sent in order from top to bottom.

  The communication control unit 36 alternately extracts messages from the first queue and the second queue of the transmission queue of the buffer 37. First, the communication control unit 36 extracts the message with the message ID “500” from the first queue and passes it to the second transmission / reception unit 39, and the second transmission / reception unit 39 attempts to transmit the message and succeeds. As a result, the message with the message ID “500” is actually transmitted to the ECUs 1b, 1b,... Via the communication line 2b. Next, the communication control unit 36 extracts the message with the message ID “900” from the second queue and attempts transmission by the second transmission / reception unit 39. However, the communication control unit 36 cannot win the arbitration and fails to transmit. In this case, the communication control unit 36 sends the message with the message ID “900” back to the second queue. Then, the communication control unit 36 extracts the message with the message ID “400” from the first queue, tries transmission by the second transmission / reception unit 39, and succeeds in transmission.

  In the example shown in the explanatory diagram of FIG. 5, while the message with the message ID “900” is extracted for the first time and the transmission with the second transmission / reception unit 39 is attempted, the first transmission / reception unit 38 sets the message ID “800”. A message has been received and stored in the second queue. Accordingly, the communication control unit 36 next extracts the message ID “800” from the second queue and attempts transmission, and the transmission is successful.

  Thereafter, the communication control unit 36 tries to transmit by extracting messages in the order of message IDs “300”, “900”, “200”, “900”, “100” alternately from the first queue and the second queue. Among these, transmission of the message with the message ID “900” cannot win the arbitration three times, and the message with the message ID “900” is returned to the second queue every time. Then, at the next opportunity when the number of return times is equal to or greater than the predetermined number (three times), the message with the message ID “900” is not returned, but transmission is attempted until the arbitration is won and succeeds. Note that the message with the message ID “700” is received during the transmission of the fourth message ID “900”.

  As a result, as shown at the right end of the explanatory diagram of FIG. 5, message IDs “500”, “400”, “800”, “300”, “200”, “100”, “900”, “700” are sequentially arranged. A message is transmitted to the ECUs 1b, 1b,.

  Next, an example of a message relayed without being sent back for comparison is shown. FIG. 6 is an explanatory diagram illustrating an example of the order of messages relayed without being sent back. In the explanatory diagram shown in FIG. 6, as in the case shown in FIG. 5, the messages whose message IDs are “500”, “400”, “300”, “200”, “100”, and “900” at a certain point in time. Are stored in the two first and second queues. Also, messages with message IDs “800” and “700” are received during message transmission.

  In the example shown in the explanatory diagram of FIG. 6, messages are alternately extracted from the first queue and the second queue and transmission is attempted. Therefore, the message with the message ID “500” is first extracted from the first queue and transmission is attempted, and transmission is successful. However, when a message with the message ID “900” is next extracted from the second queue and transmission is attempted, transmission fails without winning arbitration. In the example shown in the explanatory diagram of FIG. 6, a message that failed to be transmitted is not sent back. Therefore, the transmission of the message with the message ID “900” continues to be attempted until successful, and the messages with the other message IDs “400”, “300”, “200”, and “100” continue to stay in the transmission queue. In the example shown in the explanatory diagram of FIG. 6, the message ID “900” is successfully transmitted in the sixth attempt. Since the messages transmitted from the other ECUs 1b, 1b,... Are prioritized in the five trials so far, the other message IDs “400” and “400” correspond to the waiting time required to receive at least five messages. The messages “300”, “200”, and “100” continue to stay in the transmission queue.

  On the other hand, in the example shown in the explanatory diagram of FIG. 5, messages with message IDs “400”, “300”, “200”, etc. are transmitted first, and do not stay in the transmission queue. In this way, by performing the return processing, it is possible to avoid a message having a relatively high priority from continuing to stay in the transmission queue in vain. Note that the low-priority message will be transmitted later by the return processing, but by setting a limit on the number of return times, the transmission is completed by the second transmission / reception unit 39 after being received by the first transmission / reception unit 38 of the relay device 3. Thus, an extremely long delay time until relaying can be avoided. For messages that have been sent over a predetermined number of times, transmission is attempted until transmission is successful, so the delay time of other messages may increase by that amount. There can be no difference in the delay time, and it can be expected that the delay time is shortened as a whole.

(Embodiment 2)
In the first embodiment, the communication control unit 36 of the CAN controller 33 is configured to perform a return process every time it is determined that it has lost the arbitration while the return number is less than the predetermined number. On the other hand, the second embodiment is configured to perform a process of returning when it is determined that the arbitration has been continuously lost more than a predetermined number of times.

  The configuration of the in-vehicle network in the second embodiment is the same as that in the first embodiment except that the details of the processing of the communication control unit 36 are different. The same reference numerals as those in the first embodiment are assigned, and detailed description of each component of the in-vehicle network is omitted, and the details of the processing of the communication control unit 36 which is a difference will be described below.

  FIG. 7 is a flowchart illustrating an example of a processing procedure in which the relay device 3 according to the second embodiment transmits a message using the CAN controller 33. The processing procedure described below shows a case where a message is transmitted by the second transmission / reception unit 39. Of the processing procedures described below, the same processing steps as those in the flowchart shown in FIG. 4 of the first embodiment are denoted by the same step numbers, and detailed description thereof is omitted.

  The communication control unit 36 starts transmission of the extracted message (S2), monitors the communication state on the communication line 2b by the second transmission / reception unit 39, and determines whether or not the arbitration has been won (S3). If the communication control unit 36 determines that the arbitration has been lost (S3: NO), the communication control unit 36 determines whether the number of arbitration losses that have continuously lost the arbitration is within a second predetermined number of times (for example, three times) (step S3). S9). If the communication control unit 36 determines that the number of arbitration losses is within the second predetermined number (S9: YES), the communication control unit 36 returns the process to step S2 and completes transmission by the other ECUs 1b, 1b,. Until the message is sent again (S2).

  The communication control unit 36 further determines that the arbitration has been lost in step S3 (S3: NO), and if it is determined that the arbitration loss count has exceeded the second predetermined number (S9: NO), the CPU 30 indicates that the transmission has failed. It is detected by a notification from the communication control unit 36, and it is determined whether or not the number of message return is equal to or greater than a predetermined number (S5).

  By the process of step S9, the transmission opportunities of low priority messages that are highly likely to lose arbitration increase. As a result, a message with a relatively high priority is transmitted preferentially by the configuration in which the return process is performed, so that message retention is avoided, and the delay time of a relatively low priority message is prevented from becoming extremely long. can do.

  The case where the communication control unit 36 transmits a message by the first transmission / reception unit 38 is the same as the processing procedure shown in the flowchart of FIG.

  FIG. 8 is an explanatory diagram illustrating an example of the order of messages relayed by the relay device 3 according to the second embodiment. The explanatory diagram of FIG. 8 shows an example similar to the explanatory diagram of FIG. 5 in the first embodiment, the order of transmission attempts shown below the block of the second transmitting / receiving unit 39, and the relay device Only the order of the actually transmitted messages shown outside 3 is different.

  As shown in the explanatory diagram of FIG. 8, in the second embodiment, the communication control unit 36 extracts the message with the message ID “900” from the second queue of the buffer 37 and attempts transmission by the second transmission / reception unit 39 for arbitration. Even if it loses, it does not return to the second queue immediately. The communication control unit 36 keeps trying to transmit the message with the message ID “900”, and sends back the message when losing three or more times in succession. As a result, as shown in the explanatory diagram of FIG. 8, in the second embodiment, when the message with the message ID “900” is sent back once but extracted for the second time, arbitration is won in the third trial. , Successfully sent.

  As a result, as shown at the right end of the explanatory diagram of FIG. 8, the message IDs “500”, “400”, “800”, “300”, “900”, “200”, “700”, “100” are arranged in this order. A message is transmitted to the ECUs 1b, 1b,. Compared with the example shown in the explanatory diagram of FIG. 5, the message with the lower message priority “900” is transmitted before the messages with the message IDs “200” and “100”.

  In this way, it is possible to avoid the message from staying in the transmission queue due to the return processing, and to set a limit on the number of return times to prevent the delay time of a low priority message from becoming extremely long. In addition, by increasing the transmission opportunities of messages with low priority, the difference from the delay time of messages with high priority can be further shortened. This makes it possible to relay data efficiently so that the priority is high and the delay time is not significantly different.

(Embodiment 3)
In the first embodiment, the communication control unit 36 of the CAN controller 33 is configured to extract the messages stored in the transmission queue of the buffer 37 in the stored order (reception order). On the other hand, in Embodiment 3, when the communication control part 36 extracts a message from a transmission queue, it is set as the structure which extracts a message with a higher priority.

  That is, the transmission queue of the buffer 37 in the third embodiment is different from the second embodiment in that it is not used in the FIFO. The communication control unit 36 according to the third embodiment stores messages that are received by the first transmission / reception unit 38 and need to be relayed in the transmission queue of the buffer 37 in the order received, as in the first embodiment. Then, when extracting the message from the transmission queue, the communication control unit 36 extracts the message having the highest priority among the messages stored in the transmission queue. Note that, instead of the message having the highest priority among all the messages stored in the transmission queue, the message having the highest priority among the predetermined number of messages from the head may be extracted.

  The communication control unit 36 determines the priority level of the message based on the numerical value represented by the message ID. The communication control unit 36 may further make a determination based on the priority included in the relay ID table 35 shown in FIG. 2 of the second embodiment.

  The configuration of the in-vehicle network in the third embodiment is the same as that in the first embodiment except that the details of the processing of the communication control unit 36 are different. The same reference numerals as those in the first embodiment are assigned, and detailed description of each component of the in-vehicle network is omitted, and the details of the processing of the communication control unit 36 which is a difference will be described below.

  FIG. 9 is a flowchart illustrating an example of a processing procedure in which the relay device 3 according to the third embodiment transmits a message using the CAN controller 33. The processing procedure described below shows a case where a message is transmitted by the second transmission / reception unit 39. Of the processing procedures described below, the same processing steps as those in the flowchart shown in FIG. 4 of the first embodiment are denoted by the same step numbers, and detailed description thereof is omitted.

  In response to the transmission instruction from the CPU 30, the communication control unit 36 extracts a message having a high priority from the transmission queue of the buffer 37 corresponding to the second transmission / reception unit 39 (step S10). The communication control unit 36 alternately extracts messages having the highest priority among the messages stored in the first queue and the second queue.

  When the communication control unit 36 loses due to arbitration when transmitting the extracted message (S3: NO), and determines that the number of reversions is less than the predetermined number (S5: NO), the communication control unit 36 transmits the transmission queue (first queue or second queue). The message with the next highest priority is extracted from the queue (step S11), and the message that was attempted to be transmitted in step S2 is returned to the transmission queue (S7).

  Through the processing of step S10 and step S11, a message having a high priority that is likely to win arbitration is preferentially transmitted. This is expected to reduce the number of trials and the number of retractions. If transmission of one message fails and another message is given a transmission opportunity, but transmission of the other message further fails, the overall delay time becomes longer. However, it can be expected that the message is efficiently transmitted by preferentially attempting to transmit a message having a higher success rate.

  The case where the communication control unit 36 transmits a message by the first transmission / reception unit 38 is the same as the processing procedure shown in the flowchart of FIG.

  FIG. 10 is an explanatory diagram illustrating an example of the order of messages relayed by the relay device 3 according to the third embodiment. The explanatory diagram of FIG. 10 shows an example in which a message received by the first transmission / reception unit 38 is transmitted from the second transmission / reception unit 39 and relayed to the ECUs 1b, 1b,. As shown in the explanatory diagram of FIG. 10, the message IDs “500”, “400”, “300”, “200”, “100”, “900”, “800” received by the first transmission / reception unit 38 at a certain point in time. ”,“ 700 ”and“ 600 ”are already stored in the transmission queue of the buffer 37 in the order of reception.

  In the explanatory diagram shown in FIG. 10, the order of messages to be transmitted by the second transceiver 39 is shown below the block of the second transceiver 39. Message transmission is attempted in order from the top to the bottom, and the message with the message ID described in parentheses is returned. In addition, the order of messages actually transmitted by the second transmission / reception unit 39 is shown outside the block of the relay device 3. This also shows that messages were sent in order from top to bottom.

  The communication control unit 36 alternately extracts messages from the first queue and the second queue of the transmission queue of the buffer 37. First, the communication control unit 36 extracts a message with the message ID “100” having the highest priority from among the messages stored in the first queue, and passes the message to the second transmission / reception unit 39. The second transmission / reception unit 39 Try to send and succeed. Thereby, the message with the message ID “100” is actually transmitted to the ECUs 1b, 1b,... Via the communication line 2b. Next, the communication control unit 36 extracts the message with the message ID “600” having the highest priority from among the messages stored in the second queue and tries to transmit the message by the second transmission / reception unit 39. Cannot be sent. In this case, the communication control unit 36 sends the message with the message ID “600” back to the second queue. Then, the communication control unit 36 extracts the message with the message ID “200” having the next highest priority from the first queue, attempts transmission by the second transmission / reception unit 39, and succeeds in transmission.

  Thereafter, the communication control unit 36 alternately extracts a message with the highest priority from the first queue and the second queue. Specifically, messages are extracted in the order of message IDs “600”, “300”, “600”, “400”,. Of these, the transmission of the message with the message ID “600” does not win the arbitration twice, and is returned to the second queue three times in total. Therefore, at the next opportunity when the number of retractions reaches the predetermined number (3 times) or more, transmission of the message with the message ID “600” is attempted without success, and success is achieved until arbitration is won.

  As a result, message IDs “100”, “200”, “300”, “400”, “600”, “500”, “700”, “800”, “800”, “ Messages are transmitted to the ECUs 1b, 1b,.

  In this way, it is possible to avoid the message from staying in the transmission queue due to the return processing, and to set a limit on the number of return times to prevent the delay time of a low priority message from becoming extremely long. In addition, it is possible to reduce the number of transmission failures by preferentially transmitting a message having a high priority, and to relay data efficiently as a whole.

  In the first to third embodiments, the CPU 30 reads the control program stored in the ROM 31 so that the operation as the relay device 3 is realized. However, the present invention is not limited to this, and the processing performed by the CPU 30 implemented in software may be hardware and may be a relay device configured using an ASIC (Application Specific Integrated Circuit) and an FPGA (Field Programmable Gate Array). . In this case, the ASIC or FPGA is secured in the buffer 37 on the basis of a buffer storage processing circuit that performs processing for storing the messages received by the CPU 30 in the CAN controller 33 in the buffer 37 in the order received, for example, and a set extraction ratio. Circuits that implement the processing procedures of FIGS. 4, 7, and 9 such as a message extraction circuit that sequentially extracts messages from the transmission queue and a return count determination circuit that determines whether or not the return count is greater than or equal to a predetermined count. Consists of including.

  It should be understood that the embodiments disclosed above are illustrative in all respects and are not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the meanings described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a block diagram showing a configuration of an in-vehicle network in Embodiment 1. FIG. It is explanatory drawing which shows the example of the content of the relay ID table memorize | stored in ROM of the relay apparatus. 6 is an explanatory diagram illustrating an overview of message relay processing by a CAN controller of a relay device according to Embodiment 1. FIG. 6 is a flowchart illustrating an example of a processing procedure in which the relay device according to the first embodiment transmits a message using a CAN controller. 6 is an explanatory diagram illustrating an example of an order of messages relayed by a relay device in Embodiment 1. FIG. It is explanatory drawing which shows the example of the order of the message relayed without returning. 10 is a flowchart illustrating an example of a processing procedure in which the relay device according to the second embodiment transmits a message using a CAN controller. FIG. 10 is an explanatory diagram illustrating an example of an order of messages relayed by a relay device in the second embodiment. 10 is a flowchart illustrating an example of a processing procedure in which a relay device according to Embodiment 3 transmits a message using a CAN controller. 12 is an explanatory diagram illustrating an example of the order of messages relayed by a relay device in Embodiment 3. FIG.

Explanation of symbols

1a, 1a, ..., 1b, 1b, ... ECU
2a, 2b Communication line 3 Relay device 30 CPU
31 ROM
35 relay ID table 33 CAN controller 36 communication control unit 37 buffer 38 first transmission / reception unit 39 second transmission / reception unit

Claims (6)

In a relay device that is connected to a plurality of communication lines and transmits data to be transmitted with priority given from other external devices connected to the respective communication lines to other external devices,
Receiving means for receiving data transmitted from an external device;
Storage means for storing data received by the receiving means in the order of reception;
Based on the sequence of data being memorize in the storage unit, a transmission control means for determining the order in which Ru trying to send to extract the data,
Transmission means for attempting to transmit data based on the order determined by the transmission control means;
Means for returning the data to the storage means if transmission of the data by the transmission means fails;
Each time data is returned by the means, means for counting the number of times returned in association with the data,
When the data is transmitted by the transmission unit, if the number of times associated with the data is equal to or greater than a predetermined number, transmission is attempted until the transmission is successful. The data transmission by the transmission means fails, and when returning the data to the storage means, the data is stored again at the head of the data stored in the storage means. Relay device. The relay apparatus according to claim 1 or 2, wherein the data is returned to the storage means when transmission of data by the transmission means has failed continuously for a predetermined number of times or more. The relay apparatus according to any one of claims 1 to 3, wherein the transmission control unit preferentially extracts and transmits data having a high priority. Means for storing a table in which priority data and non-priority data to be transmitted preferentially are distinguished;
The relay apparatus according to any one of claims 1 to 4, wherein the transmission control means preferentially extracts and transmits the priority data stored in the table. A relay device connected to a plurality of communication lines and connected to an external device via each of the communication lines transmits data transmitted with priority given from the external device to another external device. In the method of relaying data,
Receive data sent from an external device,
Store the received data in the buffer in the order received,
To determine the order in which Ru attempts to transmit the extracted data from the buffer based on the sequence of data being memorize in said buffer,
Attempt to send data based on the determined order,
If data transmission fails, return the data to the buffer,
Count the number of returns,
The relay method according to claim 1, wherein the data having the number of times equal to or greater than the predetermined number is tried to be transmitted until the transmission is successful.

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