JP2009253557A - On-board relay connection unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform relay processing for normal messages without delay when error messages come continuously from an abnormal ECU in a short time. <P>SOLUTION: An on-board relay connection unit includes: a plurality of interfaces connected to each bus; counters which are connected to a receiver of each of the interfaces for counting the identifiers (ID) and receiving time of received messages; a storage part which stores a relay table to specify a transmission destination bus for a received message through the counters; a transmission buffer which is connected to a transmitter of each interface and temporarily stores a message specified in the relay table as a transmission destination bus; and an error determination processor which is connected to the plurality of counters. The error determination processor includes: a determination part that determines the same message counted by each of the counters as an error, if the receiving count of the same ID message is more than the specified value within a specified time; and a removal instruction part which removes the message determined as an error by the determination part from the transmission buffer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an in-vehicle relay connection unit, and more particularly, when an abnormal message is received from an electronic control unit connected via a bus (transmission line) in an in-vehicle LAN using CAN as a communication protocol. The transmission is stopped by detecting a message.

As the functions of automobiles increase, the number of electronic control units (ECUs) installed in automobiles also tends to increase. This type of ECU is connected to a large number of buses and has a predetermined communication protocol, for example, a CAN (Controller
It is connected to an in-vehicle LAN (Local Area Network) compliant with the Area Network protocol, and relays and connects messages between ECUs.

  When the number of ECUs connected to the in-vehicle LAN increases, the amount of messages transmitted and received via the bus (data traffic amount) also increases, and the communication load factor of the in-vehicle LAN increases. In addition, the probability that a message including data to be periodically output from the ECU collides with another message is increased, and the transmission interval of the message is disturbed. Therefore, the delay time of message transmission tends to increase. Therefore, in the in-vehicle LAN, each function is divided into several areas (segments) and each segment is connected via the relay connection unit (gateway) to suppress the data transmission amount (traffic volume) in each segment. It is planned to do. (See Patent Document 1)

Conventionally, as a relay connection unit for an in-vehicle LAN, in Patent Document 2, as shown in FIG. 4, a message input from each bus 3 via a receiving unit of the port 4 is shared buffer unit connected to each bus. 6 is temporarily stored.
By providing the shared buffer unit, even if a specific bus is temporarily in a high load state, all messages to be relayed are temporarily held in the shared buffer unit, and the transmission destination of the message is transmitted by the transmission management unit. When it is confirmed that the bus is ready for transmission, a message temporarily stored in the shared buffer unit is transmitted to the corresponding bus from the transmission unit of the port connected to the bus.
In the relay connection unit having this configuration, there is an advantage that even if a specific bus is in a high load state, it is possible to relay without causing a situation in which a message to be transmitted is not transmitted.

  However, when an abnormality occurs in the ECU connected to the bus, messages are continuously sent from the abnormal ECU to the shared buffer unit of the relay connection unit via the bus in a short cycle. As a result, there is a problem that the shared buffer unit is occupied by an abnormal message, and the relay of messages from other normal ECUs is greatly delayed.

JP 2007-318199 A JP 2007-135107 A

  The present invention has been made in view of the above problems, and even if an abnormality occurs in the ECU connected to the bus and an abnormal message continues to be transmitted from the ECU to the relay connection unit, the abnormal message The problem is to prevent delays in relaying messages from other normal ECUs.

In order to solve the above problems, the present invention is a relay connection unit that is interposed between buses to which an electronic control unit is connected, and relays messages transmitted and received between the electronic control units belonging to different buses.
A plurality of interfaces respectively connected to each of the buses;
A counter for connecting to a receiving unit of each of the plurality of interfaces and counting an identifier (ID) of a message to be received and a reception time;
A storage unit that stores a relay table that identifies a destination bus of a message received through the counter;
A transmission buffer unit connected to the transmission unit of each interface unit and temporarily storing a message specified as a transmission destination bus in the relay table;
An abnormality determination processing unit connected to the plurality of counters,
The abnormality determination processing unit is configured to determine that a message having the same ID counted by each counter is abnormal when the number of receptions within a set time is equal to or greater than the set number of times, and a message determined to be abnormal by the determination unit An in-vehicle relay connection unit is provided that includes an erasure instruction unit that erases data from the transmission buffer unit.

As described above, the relay connection unit of the present invention does not provide a shared buffer unit as in Patent Document 2, but separately provides a buffer unit for each interface transmission unit connected to each bus. When a message is received from the bus, it is temporarily stored in the corresponding buffer unit using a relay table consisting of a routing table, so abnormal messages are temporarily held only in the buffer unit specified as the destination. The Therefore, other destination buffer units are not occupied by abnormal messages, and no delay occurs in normal message transmission.
In addition, the counter counts the number of times an abnormal message is received by the counter for the buffer unit holding the abnormal message, and if the abnormal message reaches the set number of times within a predetermined time, the centralized abnormality determination processing unit is abnormal to the buffer unit. Since the instruction to delete the message is issued, the buffer part holding the abnormal message is not occupied by the abnormal message, and the transmission of the normal message transmitted from the transmitter connected to the buffer part is greatly delayed. Can be prevented.
Furthermore, since a message is temporarily stored by providing a transmission buffer unit for each bus, even if the destination bus is heavily loaded, the message can be transmitted without fail.

And, since the message received from each bus is first temporarily stored in the transmission buffer unit connected to the relay destination bus with reference to the routing table without detecting the presence or absence of the abnormality, the message Relay processing can be performed without delay, and in particular, relay processing of a message from a normal ECU can be performed quickly.
Abnormality detection of messages is centrally performed by the abnormality determination processing unit, and deletion of a message determined to be abnormal is instructed to the transmission buffer unit that has already stored the message. The transmission buffer unit storing a message is not occupied by an abnormal message, and can be normalized quickly.

  In the abnormality determination processing unit, for example, it is determined to be abnormal when a message having the same ID is counted five times or more within 2 seconds to 5 seconds.

That is, when an abnormality occurs in the ECU, the ECU itself continues to send a message in a very short cycle. Therefore, if an abnormal message is received a predetermined number of times within a predetermined time as described above, it is an abnormal message. Can be determined.
Also, because abnormal messages are determined in a short time as described above, abnormal messages can be quickly deleted in the transmission buffer unit that temporarily stores abnormal messages, and the transmission buffer unit is occupied by abnormal messages. Can be prevented.

  As described above, in the relay connection unit of the present invention, since the transmission buffer unit is provided separately for each interface connected to each bus, even if an abnormal message is received from an abnormal ECU, the transmission of the abnormal message is performed. By simply holding the abnormal message in the trust buffer unit, the abnormal message is not held in the transmission buffer unit connected to another bus through the interface, and the normal state can be maintained. Therefore, unlike the case of Patent Document 2, since the message transmitted to each bus through the shared buffer unit is not held, the buffer unit is occupied by a message from an abnormal ECU, and the relay of a message from another normal ECU is significantly delayed. Can be prevented.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a basic configuration of an in-vehicle LAN in which a plurality of buses 3 (3A, 3B, 3C) each connected to an ECU 2 (2A, 2B, 2C) are connected to a relay connection unit 10, and the in-vehicle LAN conforms to a CAN protocol. A compliant communication method is adopted. FIG. 2 shows a basic configuration of the relay connection unit.

As shown in FIG. 2, the relay connection unit 10 includes a plurality of interfaces 11 (11 </ b> A, 11 </ b> B, 11 </ b> C) connected via the bus 3 and the interface 2 a of each ECU 2 connected to each bus 3. That is, the number of interfaces 11 corresponding to the number of connected buses 3 is provided.
Each interface 11 includes a transmission unit T and a reception unit R. The reception unit R is connected to the counter 13 and to the relay processing unit 24. The relay processing unit 24 is connected to a ROM that stores a routing table 26 indicating message relay destinations, and specifies a destination bus for messages received from each receiving unit R.
Each transmission unit T is connected to a transmission buffer unit 15 (15A, 15B, 15C), and these transmission buffer units 15 are connected to the relay processing unit 24 via switching means 17 (17A, 17B, 17C). ing.

  Each counter 13 connected to the receiving unit R of each interface 11 is connected to the determination unit 21 of the concentrated abnormality determination processing unit 20. The determination unit 21 is connected to an erasure instruction unit 22, and the erasure instruction unit 22 is connected to each transmission buffer unit 15 connected to the transmission unit T of each interface unit 11.

Each counter 13 receives an identifier (ID) of a message received from the receiving unit R of the interface 11 and counts the reception time of the same ID. The counting result of the counter 13 is determined by the determination unit 21 of the concentration abnormality determination processing unit 20 to determine whether the number of receptions within the set time defined by the same ID exceeds the set number. For example, when a message with the same ID exceeds the set number of times within 3 seconds of the set time, that is, when the sixth reception is detected, the determination unit 21 transmits from the ECU 2 that transmits the message with the ID. Is determined to be abnormal. As described above, when it is determined that the message is abnormal, the message having the ID sends a determination signal NG to the erasure instruction unit 22.
The set time and the set number of times for determination by the determination unit 21 are appropriately set according to each ECU that transmits a message and the message transmission cycle.

  Upon receipt of the determination signal NG, the erasure instruction unit 22 sends the determination signal NG to each transmission buffer unit 15, and each transmission buffer unit 15 stores the ID message having received the determination signal NG. Message has been deleted.

As shown in FIG. 3, each transmission buffer unit 15 stores in the order of reception (100, 200,... 500) and stores the destination address (400, 300...) In a chain structure format. ing. Therefore, when a message including the same ID as the ID included in the determination signal NG is deleted from the stored messages, the message transmission order is increased.
The transmission buffer 15 sequentially sends the stored messages to the transmission unit T of the interface 11 based on the transmission order, and transmits the messages to the bus 3 from the transmission unit T. A message is being received.

  When the message ID counted by the counter 13 is equal to or less than the set number of times (for example, 5 times or less) within the set time, the determination unit 21 determines that the message is in a normal state, and the determination The signal OK may be sent to the relay processing unit 24 together with the abnormality determination NG.

The relay processing unit 24 receives messages from the receiving unit R of each interface 11 in the order received, identifies the destination bus with reference to the routing table 26 based on the received message ID, and identifies the identified destination The switching means 17 is turned on and transmitted to the transmission buffer unit 15 connected to the bus 3 (3A, 3B, 3C).
That is, the message is transmitted to the transmission buffer 15 that is the destination of the message without waiting for the process of determining the abnormality of the received message, and the relay processing in the relay processing unit 24 is speeded up.
The switching means 17 is formed using, for example, an AND or OR logic element.

Next, the operation of the relay connection unit 10 having the above configuration will be described.
A message from the bus 3A connected to the ECU 2A is received by the receiving unit R of the interface 11A.
The received message is sent to the relay processing unit 24. The relay processing unit 24 refers to the routing table 26 and identifies, for example, the transmission destination bus 3C, and the transmission unit R of the interface 11C of the transmission destination bus 3C. The switching means 17C connected to is closed, a message is sent to the transmission buffer 15C, and temporarily stored in the transmission buffer unit 5C.

Messages transmitted from the ECUs 2B and 2C connected to the other buses 3B and 3C are also temporarily stored in the transmission buffer unit 15 connected to the destination bus in the same procedure.
For example, a message received from the ECU 2B via the bus 3B is temporarily stored in the transmission buffer unit 15C connected to the bus 3C. A message received from the ECU 2C via the bus 3C is temporarily stored in the transmission buffer 15B connected to the bus 3B.
Therefore, messages from the ECU 2A and the ECU 2C are stored in the transmission buffer unit 5C connected to the bus 3C, and stored in the order of reception.

  At that time, if the ECU 2A is abnormal and the messages transmitted from the ECU 2A are continuously transmitted in a short time, the messages from the ECU 2A are concentrated and stored in the transmission buffer unit 5C in a short time. The For example, the data of the reception ranks 200, 300, and 400 shown in FIG. 3 is the message data (5) from the abnormal ECU 2A, and the transmission rank of the message data (2) from the normal ECU 2B is the rear rank.

  On the other hand, for the message transmitted from the ECU 2A and received by the receiving unit T of the interface 11A, the counter 13 simultaneously counts the number of receptions and the reception cycle (time). The reception result of the counter 13 is sent to the determination unit 21 of the concentration abnormality determination processing unit 20. When the number of transmissions of the message from the ECU 2A exceeds the set number within the set time, the determination unit 21 determines that there is an abnormality, and the deletion instruction unit 22 transmits the message deletion instruction to each transmission buffer unit 17. The transmission buffer unit 15C that has received the erasure instruction erases the message data (5) of the reception ranks 200, 300, and 400 based on the erasure instruction. Therefore, the message data (2) from the normal ECU 2B in the subsequent order is not advanced in transmission order and the transmission time is not delayed.

  Further, the abnormal message from the ECU 2A is stored only in the transmission buffer unit 15C connected to the destination bus 3C, and is not stored in the transmission buffer units 15A and 15B connected to the other buses 3A and 3C. Therefore, the messages transmitted to the buses 3A and 3C are not delayed by the abnormal message, and can be transmitted quickly.

Thus, since the relay connection unit of the present invention is provided with the transmission buffer unit in the transmission unit of the interface connected to each bus, a message from an abnormal ECU is transmitted to the transmission buffer unit connected to the destination bus. It is possible to prevent transmission delay of normal messages transmitted to other buses.
Also, the transmission buffer unit that stores the abnormal message is erased when it is determined to be an abnormal message, and since this determination is made in a short time, the transmission buffer unit is occupied by the abnormal message. Occurrence can be prevented, and transmission delay of normal messages stored in the transmission buffer unit can also be prevented.

It is the schematic which shows the structure of the vehicle-mounted LAN formed using the relay connection unit of this invention. It is a block diagram of the relay connection unit of the embodiment of the present invention. It is explanatory drawing which shows the memory | storage state of the message in the buffer part for transmission of the said relay connection unit. It is a block diagram which shows the conventional relay connection unit.

Explanation of symbols

2 (2A, 2B, 2C) ECU
3 (3A, 3B, 3C) Bus 10 Relay connection unit 11 (11A, 11B, 11C) Interface 13 Counter 15 (15A, 15B, 15C) Transmission buffer unit 17 Switching means 20 Concentration abnormality determination processing unit 21 Determination unit 22 Erasing Instruction unit 24 Relay processing unit 26 Routing table

Claims (2)

A relay connection unit that is interposed between buses connected to an electronic control unit and relays messages transmitted and received between the electronic control units belonging to different buses;
A plurality of interfaces respectively connected to each of the buses;
A counter for connecting to a receiving unit of each of the plurality of interfaces and counting an identifier (ID) of a message to be received and a reception time;
A storage unit that stores a relay table that identifies a destination bus of a message received through the counter;
A transmission buffer unit connected to the transmission unit of each interface unit and temporarily storing a message specified as a transmission destination bus in the relay table;
An abnormality determination processing unit connected to the plurality of counters,
The abnormality determination processing unit includes a determination unit that determines that the message with the same ID counted by each counter is abnormal when the number of receptions within a set time is equal to or greater than the set number of times, and An in-vehicle relay connection unit comprising: an erasure instruction unit for erasing from the transmission buffer unit.   The in-vehicle relay connection unit according to claim 1, wherein the abnormality determination processing unit is configured to determine that an abnormality is detected when a message with the same ID is counted five times or more within 2 seconds to 5 seconds.

Images