KR20100020253A - Monitoring apparatus for message transmission in network for a vehicle - Google Patents

Abstract

PURPOSE: A monitoring apparatus for message transmission in network for a vehicle is provided to manage a vehicle network based on the message by managing the number of times exceeding the waiting time. CONSTITUTION: The latency time information storage(36) stores the standby time information. The standby time information in advance defines in each message used in the vehicle network. The latency counter(38) counts the times in which the receiving time of each message exceeds the waiting time defined as described above. The message manager(34) uses the standby time information of the incoming message. The incoming message exceeds the defined time is determined and the standby state of the incoming message is determined according to the count value of the latency counter, and stores in the message state storage(40).

Description

Device for diagnosing message transmission status in vehicle network {MONITORING APPARATUS FOR MESSAGE TRANSMISSION IN NETWORK FOR A VEHICLE}

The present invention relates to an apparatus for diagnosing message transmission status in a vehicle network, and more particularly, to provide networking between electronic control units (ECUs) provided in a vehicle using a control area network (CAN) protocol. The present invention relates to a technology for diagnosing a message transmission state based on a wait timeout state for each message in a vehicle network.

As vehicles become more advanced, various functions are provided to provide the driver with comfort and convenience. In general, in order to perform functions provided to a vehicle, electronic control units (ECUs) are mounted to perform the corresponding functions, and electronic control units that need to be interlocked with each other are connected through a wire. Therefore, as the electronic control device increases, the wire connection becomes inevitably complicated, and as the wire connection becomes complicated, the total wire amount also increases. This causes a problem that it is difficult to find the cause of the failure when diagnosing the failure of the vehicle and a problem that the total weight of the vehicle is increased.

In addition, considering that modification of related hardware is inevitable when design changes, each electronic control device is complicatedly connected by wires, so it is difficult to secure design margin due to new installation of wires required for hardware changes. There is a problem that the change is difficult.

In order to solve the above problems, a vehicle network for realizing networking between electronic control devices using a communication bus has been proposed, and controller area network (CAN) communication is used as one of the vehicle networks. According to CAN communication, all electronic controls configured in a vehicle realize mutual networking using the CAN protocol while connected via the CAN bus.

In a state where there are not many electronic controllers connected to CAN communication, since the amount of data transmitted and received between the electronic controllers is small, a node of the CAN bus is not high, thereby providing a stable communication environment. However, as the performance of the vehicle is advanced, electronic control devices for implementing new functions are increasingly connected to the vehicle network, thereby increasing the data transmitted / received through the communication bus corresponding to the CAN bus.

In general, the utilization of the network can be calculated by Equation 1, and it is desirable to limit the utilization of the CAN bus to be at most 30% of the available value.

Bus utilization = maximum transmit bits per unit time / transmit bits per unit time

Limiting the maximum utilization of the entire network to less than 30% is because the waiting time of messages caused by arbitration is small enough for networks with less than 30% utilization. If the network utilization exceeds 30%, the time required for arbitration increases due to frequent collisions between messages for bus occupancy. In this case, in order to guarantee the priority, a message having a low priority is transmitted later for a high priority message. Thus, low priority messages have more latency than high priority messages. When the waiting time is increased for the above reason, since the predictability of the time behavior of the entire system is lowered, there is a problem that it is difficult to guarantee the normal operation of the system.

Accordingly, in order to improve data transmission efficiency and reliability of a vehicle network, development of a technology for monitoring and diagnosing a message transmission state is required.

1 is a flowchart illustrating a conventional method for managing message transmission by timeout.

As illustrated in FIG. 2, the vehicle network described with reference to FIG. 1 includes a plurality of electronic controllers 20 to 100 (hereinafter referred to as “ECUs”) connected through a CAN bus 300. The vehicle network shown in FIG. 2 is an example of a high speed CAN communication network topology.

The ECUs 20 to 100 on the vehicle network perform a function of transmitting and receiving data based on a CAN protocol, and determine an error state by checking a time out state of the reception process of the data.

A method of managing a message transmission error by a conventional timeout will be described in detail with reference to FIG. 1.

When the ignition on time elapses (Yes in S4) in the standby state (S2), each ECU 20 to 100 determines that the preparation time has elapsed (S6) and counts a timer for each message (S8).

The ECU resets the timer of the corresponding message and returns to the initial state if a reception interrupt is detected while counting the timer for each message (Yes in S10). Here, the reception interrupt is an event that occurs when the message to be received is completed.

On the other hand, if the reception interrupt is not detected while counting the timer for each message (No in S10), it is determined whether the time neighbor time has elapsed (S14).

If it is determined in step S14 that the timeout period has elapsed (Yes in S14), it is determined that the message reception fails (S16), and after determining as a temporary failure (S18), the number of temporary failure determinations reaches the number of complete failure determinations. It is determined whether (S20).

If it is determined in step S20 that the number of temporary failure determinations reaches the number of complete failure determinations (YES in S20), the message is determined to be a time-out complete failure (S22), and a diagnostic code (DTC, Diagnostic Trouble) accordingly is determined. Code) is stored and output (S24).

On the other hand, in a vehicle network with a communication bus utilization of 70% or more, the load of the communication bus may frequently cause the latency time for low priority messages to be longer than a predefined time. have. Although the reliability of the vehicle network may be lowered as the transmission delay time of the message becomes longer, it is difficult to manage the data transmission state exceeding the waiting time while satisfying the condition corresponding to the timeout in the current vehicle network.

At present, the use of communication buses for high-end vehicles and hybrid electronic vehicles (HEVs) is approximately 50% or more, and future bus developments are expected to be 50% or more. In view of such a reality, in order to provide a highly reliable vehicle network, it is necessary to study a method that can guarantee the reliability of the vehicle network by accurately monitoring the delayed transmission time of messages that may occur sporadically.

The present invention was created in view of the above circumstances, and manages the waiting state of each message by counting the number of times that the latency time is exceeded in transmitting the message in addition to the message error caused by the time-out before the mass production of the vehicle. This allows the administrator to manage the vehicle network based on the waiting status of each message.

The apparatus for diagnosing message transmission status in a vehicle network according to the present invention is a device for diagnosing message transmission status in a vehicle network in which a plurality of ECUs are connected through a communication bus, wherein the electronic controller is used in the vehicle network. A wait time information storage unit for storing predefined latency time information for each message to be stored, a wait counter for counting a number of times that the received time of each message exceeds a predefined wait time, and a wait counter The message state storage unit stores the wait state for each message based on a counter value, and determines whether the received message exceeds the predefined time using the wait time information for the received message, and the number of times is the wait. Counted by a counter and according to the counter value of the waiting counter. It determines the idle state of the received message described below, a message management unit that stores the message status in the storage unit.

Preferably, in the present invention, the message manager may be configured to set a waiting state of the received message in a first state in which the counter value is smaller than a first criterion, in a second state in which the counter value is greater than or equal to a first criterion and smaller than a second criterion. It can be determined as a third state whose value is greater than or equal to the second criterion.

Preferably, in the present invention, when the received message is classified into a third state, the message manager may store a load value of the communication bus at the time when the received message is received in the message state storage unit.

Preferably, in the present invention, the third state may be a state in which a redesign of the vehicle network is required to ensure reliability of data transmission for the received message.

According to the apparatus for diagnosing message transmission status in a vehicle network according to the present invention, the operator can manage the vehicle network based on the standby state of each message before mass production of the vehicle, thereby creating a stable and reliable vehicle network during mass production of the vehicle. There is an effect that it can provide.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The vehicle network to which the present invention is applied may be configured as shown in FIG. 2, and each ECU 10, ..., 100 performs a function of managing a wait timeout state for a received message.

3 is a detailed block diagram of an ECU according to an embodiment of the present invention.

The ECU includes a CAN controller 32, a message manager 34, a wait time information storage 36, a wait counter 38 and a message state storage 40.

The CAN controller 32 receives the CAN protocol based message transmitted through the communication bus, performs an error check, and transmits the received message to the message manager 34. As is known, messages based on the CAN protocol have IDs (identifiers), and each ECU distinguishes and prioritizes the messages based on the ID of each message. For each message, the latency time promised by the CAN protocol is defined, and the minimum time (Min) / maximum time (Max) is defined for each wait time. Therefore, the message must be received via the communication bus to the receiving ECU within the waiting time defined for that message.

The latency information storage unit 36 stores latency information defined for each message for each message ID. In the present invention, the waiting time information includes information on the minimum time and the maximum time for the waiting time.

The message manager 34 determines whether the transmission state of the received message satisfies the waiting time with respect to the received message, and according to the determination result, the message manager 34 determines the active state of each received message as "active" and "passive". And "missing". Each wait state is sequentially transitioned based on the number of times the message does not meet a predefined wait time. That is, when the number of times that the waiting period is not satisfied is less than the first criterion, for example, "128", the state transitions to the "active" state, and the message of the "active" state corresponds to a state in which data transmission is good. In addition, when the number of times that the waiting period is not satisfied exceeds the first criterion but is less than the second period, the state transitions to the "passive" state. A message in the "passive" state is waiting for timeout during data transmission. Corresponds to When the number of times that the waiting period is not satisfied exceeds the second criterion, the state transitions to the "missing" state. A message of the "missing" state corresponds to a state in which a serious waiting timeout occurs during data transmission. In particular, the "missing" state corresponds to a state that may affect the reliability of the network because the excess of the waiting time in the transmission of the message is a serious level. Thus, in the "missing" state, a redesign of message ID assignment, message mapping, and period for the message is required.

The wait counter 38 counts the number of times the waiting time is exceeded for each message (by ID) under the control of the message manager 34 and stores a counter value corresponding to the result.

The message state storage unit 40 stores the state of the message determined according to the excess state of the waiting time for each message (by ID) under the control of the message manager 34.

Hereinafter, a method of diagnosing message transmission status in a vehicle network according to an embodiment of the present invention will be described with reference to the flowchart shown in FIG. 4.

When the CAN controller 32 of each ECU receives a CAN protocol based message, it performs an error check on the message, and then transmits the received message to the message manager 34 (S2).

The message manager 34 loads wait time information on the received message from the wait time information storage 36 (S4), and the time at which the received message is actually received is defined in advance using the loaded wait time information. It is determined whether it belongs to the range of the waiting time which was carried out (S6).

As a result of the determination, if it is determined that the reception time of the received message is within the range of the waiting time (Yes in S6), the standby state of the received message is kept in an "active" state and the flow proceeds to step S2.

On the other hand, if it is determined in step S6 that the reception time of the received message does not fall within the range of the waiting time (No in S6), the counting value of the waiting counter corresponding to the received message is increased to "1" (S10). .

Subsequently, it is determined whether the value of the increased waiting counter is a first reference, for example, "128" (S12). If the value of the waiting counter corresponds to "128" of the first reference, the received message is determined. The standby state is shifted to the "passive" state (S14).

If it is determined in step S12 that the value of the wait counter does not correspond to "128" which is the first criterion (No in S12), the message manager 34 determines "128" whose wait counter value for the received message is the first criterion. If it is determined whether or not (S16), the determination result is that the wait counter value does not exceed "128" (S16) and proceeds to step S2 to wait for message reception.

However, in contrast, when it is determined in step S16 that the wait counter value exceeds "128" which is the first criterion (YES in S16), the message manager 34 determines whether the wait counter value is "256" which is the second criterion. (S18).

As a result of the determination in step S18, if the wait counter value matches "256" which is the second criterion (Yes in S18), the standby state of the received message is shifted to the "missing" state (S20) and the process proceeds to step S2 to receive the message. Wait

Meanwhile, if the wait counter value does not match the second criterion "256" (No at S18), the message manager 34 determines whether the wait counter value exceeds "256" as the second criterion. It is determined (S24).

If the wait counter value exceeds " 256 " (Yes in S22), the message manager 34 transmits the load value of the communication bus corresponding to the reception point of the message to the message state storage unit 40. Save it. The load value of the communication bus may be provided from a separate measurement tool, or the measurement tool may be installed in the message manager 24.

Alternatively, if the wait counter value does not exceed " 256 " (No in S22), the message manager 34 waits for the message reception.

Through the above-described process, as the communication bus load values in the waiting state and the "missing" state are stored for each ID of the received message, the administrator can reassign the ID or redesign the message mapping and the period based on this.

On the contrary, if the received message is determined to be "active" through the above-described process, after calculating the latency distribution for each message in the state, the network design state of the current state is maintained. Since the process of calculating the latency distribution for each message corresponds to a known technique in the vehicle network design process, a detailed description thereof will be omitted.

This message diagnosis process enables the design of a vehicle network with optimal conditions, which improves the communication efficiency in the vehicle network and the robustness of the CAN communication bus.

1 is a flowchart for explaining a conventional method for managing message transmission by timeout;

2 illustrates a vehicle network topology.

3 is a detailed configuration diagram of an electronic control unit (ECU) applied to a vehicle network according to an embodiment of the present invention.

4 is a flowchart for explaining an operation of an apparatus for diagnosing message transmission status in a vehicle network according to an embodiment of the present invention.

Claims (4)

In the apparatus for diagnosing message transmission status in a vehicle network in which a plurality of ECUs are connected through a communication bus, The electronic control device A standby time information storage unit which stores predefined latency time information for each message used in the vehicle network; A waiting counter that counts the number of times that each message received time exceeds a predefined waiting time; A message state storage unit for storing a wait state for each message based on a counter value of the wait counter; Determining whether the received message exceeds the predefined time using the waiting time information for the received message, the number of times is counted by the waiting counter, and according to the counter value of the waiting counter A message manager to determine a waiting state and store the message in the message state storage unit; Device for diagnosing message transmission status in a vehicle network. The method of claim 1, wherein the message management unit A first state in which the counter value is smaller than a first reference, a second state in which the counter value is greater than or equal to a first criterion, and a third state in which the counter value is greater than or equal to a second criterion; Decided by Device for diagnosing message transmission status in a vehicle network. The method of claim 2, wherein the message management unit When the received message is classified into a third state, the load value of the communication bus at the time when the received message is received is stored in the message state storage unit. Device for diagnosing message transmission status in a vehicle network. The method of claim 2 or 3, wherein the third state is The redesign of the vehicle network is required to ensure the reliability of data transmission for the received message. Device for diagnosing message transmission status in a vehicle network.

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