JP2009171310A - Communication apparatus, and fault determination method in communication apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication apparatus capable of accurately deciding that a transmission node is broken down or not even when reception messages are received excessively, to provide a fault decision method using the communication apparatus, and to provide a communication apparatus or the like capable of avoiding a failure of a system even when the reception messages are increased. <P>SOLUTION: The communication apparatus is connected with a plurality of communication apparatuses via a bus and receives a frame as one communication unit from each of the plurality of communication apparatuses, and the communication apparatus includes: a receiving section for receiving the frame from the other communication apparatus and a fault determining section for determining, when reception interval in the continuous reception of the frames is shorter than or equal to a predetermined time and the continuously received frames come from the same communication apparatus, that the communication apparatus which has transmitted the continuous frames is broken down. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a communication device and a failure determination method in the communication device.

  Recently, a CAN (Controller Area Network) protocol is attracting attention as an in-vehicle network of an automobile (for example, Non-Patent Documents 1 and 2 below). CAN is a serial communication protocol internationally standardized by ISO (International Organization for Standardization).

  The feature of the CAN protocol is that it adopts a multi-master system that allows all nodes to send frames (or messages, communication unit of CAN protocol) when the bus is free, and sent frames at the same time. In some cases, a node that transmits a frame with a high-priority identifier (ID) obtains a transmission right.

  Since the CAN communication protocol employs a multi-master system, the number of received messages per time varies depending on the transmitting node. When the transmitting node fails, for example, the receiving node receives a large number of messages. If the reception load increases, the system may not operate normally.

  Therefore, it is very important to determine the failure of the transmitting node. However, this determination is often difficult. This is because when a large number of received messages are received, there may be a temporary increase in messages generated when the receiving node is activated.

  6A and 6B are diagrams showing an example of message transmission. That is, FIG. 3A shows an example in which messages from the transmission nodes A120 to C140 are temporarily received by the reception node 100 when the power supply of the reception node 100 is turned on. FIG. 5B shows an example in which a large amount of messages are received at the receiving node 100 due to a failure of the transmitting node A120. Therefore, it is important to distinguish between the two and accurately determine the failure of the transmission node (FIG. 6B).

  Conventionally, regarding the abnormality detection of such a node, the vehicle ID of the abnormality data is stored in the storage unit, and if the number of times is equal to or greater than the predetermined number, the vehicle communication for determining that the transmission device of the vehicle having the vehicle ID is abnormal There exists an apparatus (for example, the following patent document 1).

On the other hand, there is also disclosed a multiplex communication system in which even if the same data is continuously received, it is not determined that there is an abnormality as a result of transmission using an ID frame having a high priority (for example, Patent Document 2 below).
“CAN Introduction” www.renesas.com “What is CAN?” Www.toyo.co.jp/car/CAN/CAN_General.htm JP 2006-295836 A JP-A-6-334663

  However, none of the above-mentioned patent documents describes how to determine when a large number of received messages are received. Therefore, conventionally, it has not been possible to determine whether or not the transmission node is faulty with respect to excessively received messages.

  In response to such an increase in the number of received messages, it may be possible to determine whether or not there is a failure based on the message reception interval at the receiving side node.

  However, as described above, there may be a temporary case (see FIG. 6A) at the time of activation, and the two cannot be distinguished from the reception interval.

  Therefore, the present invention has been made in view of the above problems, and the object thereof is a communication device capable of accurately determining whether or not a transmission node is out of order even when receiving messages are excessively received, and a failure determination method using the communication device. Is to provide.

  Another object of the present invention is to provide a communication apparatus and the like that can avoid system failure even when the number of received messages increases.

  In order to achieve the above object, according to one embodiment of the present invention, in a communication device connected to a plurality of communication devices via a bus and receiving a frame which is a communication unit from the plurality of communication devices, A receiving unit that receives frames from another communication device; a reception interval when the frames are continuously received is a predetermined time or less; and the continuously received frames are frames from the same communication device. If there is, the communication device that has transmitted successive frames includes a failure determination unit that determines that there is a failure.

  The communication device may further include a fail-safe processing unit that discards a frame from the communication device determined to be a failure by the failure determination unit.

  Further, in the communication device, an identification code for identifying the communication device that transmits the frame and identifying another frame is inserted into the frame, and the failure determination unit continuously receives the frame. In addition, when the frames having the same identification code are received, it is determined that the communication apparatus is in failure.

  Furthermore, in the communication device, the failure determination unit continuously receives the frames, and the communication device fails when receiving frames from the same communication device even when the identification codes are not the same. It is determined that it is.

  Furthermore, in the above communication device, the failure determination unit does not perform failure determination on the communication device even when receiving a frame from a communication device other than the communication device determined to be a failure.

  Further, in the communication device, even if the failure determination unit receives the frame continuously, the failure determination unit determines that the failure is a temporary abnormality when the frame is received from a different communication device, and the number of determinations of the temporary abnormality is When the threshold value is exceeded, it is determined that the communication device is faulty.

  In order to achieve the above object, according to another embodiment of the present invention, a communication device connected to a plurality of communication devices via a bus and receiving a frame as one communication unit from the plurality of communication devices. In the failure determination method in claim 1, a communication device that receives the frame from another communication device and receives the frame continuously is a predetermined time or less, and the continuously received frame is the same communication device. If the frame is a frame from the beginning, it is determined that the communication apparatus that has transmitted consecutive frames is faulty.

  According to the present invention, it is possible to provide a communication device capable of accurately determining whether or not a transmission node is out of order even when receiving messages are excessively received, and a failure determination method using the communication device. In addition, according to the present invention, it is possible to provide a communication device or the like that can avoid a system failure even if the number of received messages increases.

  The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is an example of an in-vehicle network system 1. In the in-vehicle network system 1, a plurality of nodes (hereinafter, ECU: Electric Control Unit) 10, 21 to 24 are connected via a bus 30. The communication protocol of the bus 30 is a CAN protocol. Other communication protocols that employ a multi-master method can also be implemented.

  Each ECU 10, 21 to 24 is an example of a vehicle communication device, and controls each hardware of the automobile. Examples of the ECU include an engine ECU that controls an engine, a transmission, and the like, and an information ECU that controls a VICS navigation.

  Here, each ECU10, 21-24 is the same structure, and ECU10 is demonstrated on behalf of it. The ECU 10 includes a microcomputer 11 and a CAN transceiver 12.

  The microcomputer 11 performs various processes, and includes a RAM 110, a ROM 111, a calculation unit 112, a CAN controller 113, and an I / O 114.

  The ROM 111 stores a program for executing various processes such as a failure determination process and a fail-safe process described later. The calculation unit 112 reads a program from the ROM 111 and actually executes various processes. The RAM 110 stores execution data and the like by the processing of the calculation unit 112.

  The CAN controller 113 generates data (frame or message, communication unit of CAN protocol) according to the CAN communication protocol and outputs the data to the CAN transceiver 12, or converts the data from the CAN transceiver 12 into data that can be processed by the microcomputer 11. . The I / O 114 is an interface that controls data input / output with respect to other external devices.

  The CAN transceiver 12 is connected to the bus 30, receives frames from the other ECUs 21 to 24, outputs the frames to the CAN controller 113, and transmits the frames from the CAN controller 113 to the other ECUs 21 to 24.

  Next, the operation of the ECU 10 that is the vehicle communication device configured as described above will be described. FIG. 2 shows an example of overall processing, FIG. 3 shows an example of abnormality determination processing, and FIG. 4 shows an example of fail-safe processing.

  As shown in FIG. 2, when this process is started (S10), the calculation unit 112 of the microcomputer 11 executes an abnormal process determination process (S11).

  When the process proceeds to the abnormality determination process, the calculation unit 112 confirms that the transmission side is normal (S110 in FIG. 3), and determines whether a transmission completion interrupt has occurred (S111). That is, the calculation unit 112 actually performs this processing after the transmission-side ECUs 21 to 24 have not failed and the transmission of the message from the transmission-side ECUs 21 to 24 is completed.

  If a transmission completion interrupt has not occurred (N in S111), the abnormality determination process ends (S116). On the other hand, when a transmission completion interrupt occurs (Y in S111), the calculation unit 112 checks whether a bus off has occurred (S112). Bus off is a state where transmission of messages from the ECUs 21 to 24 on the transmission side is stopped. This is determined by receiving a certain message from the other ECUs 21-24.

  When the bus-off occurs (N in S112), there is no reason to determine the transmission abnormality of the transmission side ECUs 21 to 24 thereafter, and thus the abnormality determination process ends (S116). On the other hand, when the bus-off has not occurred (Y in S112), the calculation unit 112 determines whether the reception interval of the received message is short, that is, whether the message has been continuously received (S113). For example, the threshold value is stored in the RAM 110, and the calculation unit 112 compares the threshold value with the reception interval, and determines that the reception interval is long if the reception interval is larger than the threshold value, and determines that the reception interval is short in the opposite case. Alternatively, it may be determined by measuring a reception interval for a certain period and comparing the interval with a threshold value.

  Normally, each of the ECUs 21 to 24 transmits a message at a long interval such as “1 second”. Therefore, when the message reception interval is short, it can be considered that some failure has occurred in the transmission-side ECUs 21 to 24. Therefore, when the reception interval is long (N in S113), the calculation unit 112 ends the process without determining that the transmission destination ECUs 21 to 24 are out of order (S116).

  On the other hand, when the reception interval is short (Y in S113), the calculation unit 112 determines whether or not the received messages have the same ID (S114). In the CAN protocol, an ID is assigned to each message transmitted from each ECU 10, 21 to 24 in advance for acquiring the bus transmission right, and the ID is inserted into the message. Accordingly, the calculation unit 112 can determine whether or not the same ID is obtained by extracting the ID from the received message.

  In this way, it is determined whether or not the IDs are the same. If the IDs of the messages are the same when receiving a message with a short reception interval, the sending side ECUs 21 to 24 send the same message due to some failure. This is because it can be considered that it is transmitted many times.

  With respect to this ID, the ID to be used in each of the ECUs 10, 21 to 24 is determined in advance for each of the ECUs 10, 21 to 24. For example, the ECU 21 is “1” to “10”, and the ECU 22 is “11” to “20”. Etc.

  When the IDs are the same (Y in S114), the calculation unit 112 determines that the ECUs 21 to 24 as the transmission destinations of the received message are out of order (S115).

  On the other hand, when the messages having the same ID are not received (N in S114), the calculation unit 112 determines whether the IDs are different from the same ECU 21 to 24 (S118). Whether the received message is from the same ECU 21 to 24 can be determined from the ID described above. For example, a message from the ECU 21 when the ID is “3”, a message from the ECU 22 when the ID is “20”, and the like.

  As described above, when the messages are not from the same ID, it is determined whether or not the messages are from the same ECUs 21 to 24. If any failure occurs in the sending ECUs 21 to 24, the messages having the same ID are received at a short reception interval. This is because it is conceivable to transmit not only messages but also messages with different IDs.

  Therefore, when the calculation unit 112 receives different IDs from the same ECUs 21 to 24 (Y in S118), the destination ECUs 21 to 24 determine that there is a failure (S119).

  On the other hand, when not having received different IDs from the same ECUs 21 to 24 (N in S118), the calculation unit 112 ends the failure determination process without determining that there is a failure (S116). That is, even if the reception interval of the received message is short, the arithmetic unit 112 does not determine that there is a failure if it is not a message with the same ID but a message from different ECUs 21 to 24. This is because messages are sequentially transmitted from different ECUs 21 to 24.

  The failure determination process will be described with a more specific example. FIG. 5 is a diagram for explaining such an example. The ECU 21 transmits messages having IDs “A1”, “A2”, and “A3”, respectively. The ECU 22 transmits messages with IDs “B1”, “B2”, and “B3”. The ECU 23 transmits messages with IDs “C1”, “C2”, and “C3”.

  For example, consider a case where the ECU 10 sequentially receives “A1”, “B1”, and “C1” messages. In this case, even if the reception interval is short (Y in S113), it is not determined as a failure because it is not the same ID (N in S114) and is not a message from the same ECU 21 to 24 (N in S118). This is because messages from different ECUs 21 to 24 are received at short reception intervals.

  Further, when the ECU 10 sequentially receives the messages “A1”, “A1”, and “A1”, if the reception interval is short (Y in S113), it transmits the message because it has the same ID (Y in S114). The ECU 21 determines that there is a failure (S115).

  Further, when the ECU 10 sequentially receives the messages “A1,” “A2,” and “A3” and the reception interval is short (Y in S113), it is a message from the same ECU 21 (Y in S118). Is determined to be a failure. However, even if the ECU 10 receives the messages “A1,” “A2,” and “A3” and the reception interval is long (N in S113), it does not determine that there is a failure.

  When the abnormality determination process in FIG. 3 is completed, the processing unit 112 returns to FIG. 2 and determines whether or not the transmission side is abnormal (S12). The arithmetic unit 112 determines that there is a transmission-side failure by the abnormality determination process (S115, S119), determines that it is abnormal (Y in S12), and otherwise determines that there is no abnormality (N in S12).

  When the transmission side is abnormal (Y in S12), the calculation unit 112 performs fail-safe processing (S13). On the other hand, when there is no abnormality on the transmission side (N in S12), the calculation unit 112 ends the series of processes without performing the fail-safe process (S14).

  FIG. 4 is a flowchart showing an example of fail-safe processing. After shifting to this processing, the calculation unit 112 determines whether or not the transmission side is abnormal (S130). If it is not abnormal (N in S130), the fail-safe process ends (S134).

  On the other hand, when the ECUs 21 to 24 on the transmission side are abnormal (Y in S130), the calculation unit 112 performs reception filter processing (S131). The reception filter process is a process of discarding the received message from the ECUs 21 to 24 that are the failure targets.

  Next, the calculation unit 112 stores the identification information of the transmission destination ECUs 21 to 24 determined to be faulty in the RAM 110 (S132).

  Next, the calculation unit 112 notifies the stored information to the outside (S133). For example, the ECU 10 notifies the failure target ECUs 21 to 24 and the failure target ECUs 21 to 24. The reason for notifying the failure target ECUs 21 to 24 is to inform the ECUs 21 to 24 that they are the failure target ECUs. The other ECUs 21 to 24 are notified in order to take some measures such as fail-safe in response to the messages from the ECUs 21 to 24 subject to failure.

  Then, the fail safe process ends (S134), and the sequence returns to FIG. 2 to end the series of processes (S14).

  In this way, the ECU 10 performs failure determination not only by the reception interval (S113) but also by the message ID (S114) and the frequency for each node (S118). Thus, even when the reception message is excessively received, it can be accurately determined whether or not the transmission node is out of order.

  Further, since the ECU 10 notifies the other ECUs 21 to 24 of the information of the ECUs 21 to 24 that have determined the failure (S133), the other ECUs 21 to 24 can execute some fail-safe processing based on the information and receive them. The failure of the in-vehicle network system 1 due to an increase in messages can be avoided. In addition, the fail-safe ECU 10 that has been determined to fail performs fail-safe processing by the reception filter process (S131), so that it is possible to avoid a system failure due to an increase in received messages.

  In the above-described example, other examples shown below can be implemented. That is, in the abnormality determination process (S13, FIG. 3), the calculation unit 112 has a short reception interval of received messages (Y in S113), the received messages are not the same ID (N in S114), and from the same ECUs 21-24. When it is not a thing (N in S118), it is not determined as a failure. For example, when a message having an ID of “A1”, “B1”, or “C1” is received at a short reception interval. In this case, the calculation unit 112 may determine “provisional abnormality”, store the number of occurrences since power-on in the RAM 110, and determine that the abnormality has occurred when it exceeds a predetermined number of times. Alternatively, it may be determined as abnormal when it occurs continuously for a certain number of times. For example, if “A1” to “C1” are received again at a short reception interval after receiving “A1” to “C1”, some abnormality may be considered.

  In addition, when the calculation unit 112 determines that a certain ECU 21 to 24 is malfunctioning (S115, S119), the calculation unit 112 may not perform abnormality determination based on a reception frame from another ECU 21 to 24 that is not malfunctioning. For example, when the calculation unit 112 determines that the ECU 21 is faulty, the reception message from the ECU 22 is normal, but the bus 30 is occupied by the reception message from the faulty ECU 21 and cannot be normally received. This is because it may be determined to be abnormal.

  Furthermore, when the calculation unit 112 determines that a failure has occurred (S115, S119), the fail safe value may be disclosed for data used for control.

  Further, in the failure determination process (S13, FIG. 3), the calculation unit 112 determines whether or not the reception interval is short based on a threshold value based on a certain time interval (S113). In addition, it may be determined (S113) with different intervals for each ID of the received message or for each of the transmission ECUs 21 to 24. This is because some of the transmission intervals of the messages are shorter than others by the ECUs 21 to 24 that transmit the messages. In addition, regarding the determination of whether or not they are the same ID (S114) and the determination of whether or not they are different IDs from the same ECU 21 to 24 (S118), the interval is not limited to a certain time interval, but for each ID or ECUs 21 to 24. The determination may be made at different time intervals.

  Furthermore, the ECU 10 is not limited to a vehicle communication device, and can be implemented as a communication device other than a vehicle.

FIG. 1 is a diagram illustrating a configuration example of an in-vehicle network system. FIG. 2 is a flowchart showing an example of the entire process. FIG. 3 is a flowchart illustrating an example of the abnormality determination process. FIG. 4 is a flowchart showing an example of fail-safe processing. FIG. 5 is a diagram for explaining a specific example of the abnormality determination process. 6A and 6B are diagrams showing an example of message transmission.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 In-vehicle network system, 10 ECU (Electric Control Unit), 11 Microcomputer, 12 CAN transceiver, 21-24 ECU, 30 bus | bath, 110 RAM, 111 ROM, 112 calculating part, 113 CAN controller, 114 I / O

Claims (7)

In a communication device that is connected to a plurality of communication devices via a bus and receives a frame that is one communication unit from the plurality of communication devices,
A receiving unit for receiving the frame from another communication device;
When the reception interval when continuously receiving the frames is a predetermined time or less and the continuously received frames are frames from the same communication device, the continuous frames are transmitted. A communication apparatus comprising: a failure determination unit that determines that the communication apparatus is in failure.   The communication device according to claim 1, further comprising a fail-safe processing unit that discards a frame from the communication device that is determined to be a failure by the failure determination unit. In the frame, an identification code for identifying the communication device that transmits the frame and identifying another frame is inserted,
The said failure determination part determines that the said communication apparatus is a failure, when the said frame is received continuously and the said same identification code | symbol is received. Communication equipment.   The failure determination unit determines that the communication device is in failure when receiving the frames continuously and receiving frames from the same communication device even when the identification codes are not the same. The communication apparatus according to claim 3, wherein:   The communication device according to claim 1, wherein the failure determination unit does not perform failure determination on the communication device even when receiving a frame from another communication device other than the communication device determined to be a failure.   Even if the failure determination unit continuously receives the frame, the failure determination unit determines that it is a temporary abnormality when the frame is received from a different communication device, and when the number of determinations of the temporary abnormality exceeds a threshold, The communication device according to claim 1, wherein the communication device is determined to be faulty. In a failure determination method in a communication device that is connected to a plurality of communication devices via a bus and receives a frame that is one communication unit from the plurality of communication devices.
Receiving the frame from another communication device;
When the reception interval when continuously receiving the frames is a predetermined time or less and the continuously received frames are frames from the same communication device, the continuous frames are transmitted. Determining that the communication device is faulty;
A failure determination method characterized by the above.

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