JP3059757B2 - In-vehicle multiplex transmission system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an in-vehicle device for controlling the driving of a load connected to each unit by multiplexing a message between a plurality of units distributed in a vehicle. The present invention relates to a multiplex transmission system for a vehicle, and more particularly to a multiplex transmission system for a vehicle having a backup function when the unit fails.

[Related Art] In recent years, the number of electrical components mounted on automobiles has increased dramatically, and the number of electrical components has increased dramatically with this. As a result, the wiring harness connecting the electrical components has become complicated. The demand for simplification is increasing due to the increase in size and size. An in-vehicle multiplex transmission system has been developed to meet such requirements and has been put into practical use.

As shown in FIG. 10, for example, a multiplex transmission system of this type has a plurality of multiplex units U each having a built-in CPU (central processing unit) dispersedly arranged in a vehicle, and these units U have various lamps and motors. And the like, and input accessories I such as switches and sensors for driving these output accessories O, and a transmission line N between each unit U.
Are combined.

In this system, a message is transmitted via a transmission line N between a unit U connected to an input accessory I and a unit U connected to an output accessory O driven by the input accessory I. Thereby, the drive of the load is controlled. On the transmission line N, a plurality of messages are multiplexed and transmitted by a method such as time division or frequency division, so that the wire harness can be simplified.

By the way, in this type of system, loads such as a brake lamp, a headlamp, a turn lamp and the like that are indispensable for maintaining safety are connected as the output auxiliary equipment O. For this reason, it is necessary to prevent these loads from functioning or malfunctioning due to a failure of the unit U by some method.

Conventionally, as a backup method at the time of unit failure,
When a signal from another unit for controlling a load cannot be obtained by a unit, it is known that the unit is operated with backup data stored in the unit in advance in order to safely operate the load. (JP-A-58-12002).

[Problems to be Solved by the Invention] In the conventional backup method described above, each unit diagnoses whether the input auxiliary device connected to itself is normal, and also transmits all other units to itself. Is also diagnosed, so that means such as software or hardware for such diagnosis is required. On the other hand, a unit that needs signals from many other units has a problem that the number of units to be diagnosed is large, the scale of the diagnosis means is increased, and the cost of the entire system is increased.

Further, since there are various combinations of units that transmit messages to individual units, there is a problem that a means for diagnosing a failure of each unit becomes complicated and system expandability is poor.

Further, in the conventional method, when any one of a plurality of units transmitting a message to a certain unit fails, backup means for setting a load to be operated by control from the failed unit to a fixed operation mode. Must be provided in the unit. This backup means must be provided in each unit and be able to cope with a failure of all units that send messages to each unit. For this reason, there is a problem that the amount of hardware or software for backup becomes enormous.

The present invention has been made in order to solve such a conventional problem, and can simplify the configuration of hardware or software for backup processing of each unit, and has excellent scalability in a vehicle. It is an object of the present invention to provide a multiplex transmission system.

Means for Solving the Problems An in-vehicle multiplex transmission system according to the present invention includes a plurality of units distributed in a vehicle, an input auxiliary device and an output auxiliary device connected to these units, and And a multiplex transmission of messages between the units via the transmission line to control the drive of the output auxiliary device based on a signal from the input auxiliary device via the unit. In the vehicle-mounted multiplex transmission system, a specific monitoring unit of the plurality of units includes a failure diagnosis unit that monitors whether the other unit is normal, and a unit that has been diagnosed as having a failure by the unit. And backup means for transmitting a message for backup to another unit in place of the failed unit. .

[Operation] According to the present invention, a specific monitoring unit among a plurality of units diagnoses whether or not another unit is normal, and when a certain unit is diagnosed as having failed, the monitoring unit determines whether or not the failed unit has failed. Instead, send a message to another unit. Therefore, another unit that should receive a message from the failed unit can continue its own process without any awareness that the failed unit is a failure.

Therefore, according to the present invention, since the monitoring unit sends backup data to another unit in place of the failed unit, another unit that sends a message to the unit fails if the other unit fails. There is no need to provide backup means. For this reason, the system is simplified, the cost can be reduced, and the expandability of the system is improved.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a configuration of a multiplex transmission system according to an embodiment of the present invention.

Inside the car, a plurality of multiplex units U ₁ , U ₂ , U ₃ , U ₄ ,
U ₅ is dispersed arranged. These multiplex units U ₁
~U ₅ between are connected to one another via the transmission line N.
Each of the multiplex units U _{1 to} U ₅ includes various operation switches for giving a drive command for the load and input auxiliary devices I _ij such as sensors,
An output accessory O _ij of the lamp and the motor or the like is driven is connected in accordance with a drive instruction from the input auxiliary I _ij. Here, the input auxiliary I _ij is connected to the unit U _i, based on the message transmitted from the unit U _i to unit U _j, to operate the output accessory O _ij connected to the unit U _j It is an input auxiliary device for this.

In this system, unit U ₁ is
Is a function of U ₂ ~U ₅ monitors whether the normal, and that in place of the failed unit is configured as a monitoring unit and a backup means for sending a message for backup to the other units ing.

Next, the operation of the multiplex transmission system thus configured will be described.

In the normal operation mode, for example, when an input auxiliary I ₁₂ is an operation switch of the direction indicator is operated, a message for the direction indicator drive from the unit U ₁ to the unit U ₂ is transmitted, the unit which receives the U ₂ controls the output accessory O ₁₂ is a direction indicator.

In between such operations, the monitoring unit U _1, in order to monitor whether the system is operating normally, the second
As shown, sends a message indicating the regular transmission request to other units U ₂ ~U ₅ in order. When the transmission request other units U ₂ ~U ₅ receives, it sends a response message indicating that own unit is normal to the transmission line N. As shown in FIG. 3, the message is composed of a start-of-message SOM, an identity code ID, data DATA, an error detection code CRC, an acknowledgment signal ACK, and an end-of-message EOM.

Monitoring unit U ₁ receives this response message, determines that the unit is normal. If, when the monitoring unit U ₁ is not obtained a response even to the transmission request when not obtain response after a predetermined time after the transmission request, or several times, the unit U of destination failed Judge that In this case, in addition to the failure of the units U _j itself in failure, also it includes failure due to disconnection or the like of the bifurcation of the internal unit U _j of the transmission line N.

4 is a diagram for explaining the operation in the case where the unit U ₃ other than the monitoring unit U ₁ has failed.

To the transmission request from the monitoring unit U ₁ to the unit U ₂ ~U _6, although the response from the unit _{U 2, U 4, U 5} , unit U ₃
If there is no response from the monitoring unit U ₁ the unit
It is determined that the U ₃ is faulty. And the monitoring unit U ₁
, Instead of the data to the output accessory O _34, O _35, which is controlled by a message from the unit U _3, the backup data stored in advance in the monitoring unit U ₁ unit
It is sent to units U ₄ and U ₅ instead of U ₃ . At the same time monitoring unit U ₁ by processing such as lighting an alarm lamp of the meter, indicating that the abnormality in the system occurs in the driver.

At this time, the backup data is
₃₄ and O ₃₅ are determined to operate in a direction that does not reduce safety. For example, when the output auxiliary device O ₃₄ is a headlamp, data for turning it on is set as backup data, and when the output auxiliary device O ₃₄ is a nozzle control device of a fuel injection device, Then, data that reduces the engine speed to a certain value is set as backup data. In addition, these output accessories O ₃₄ ,
If O ₃₅ has a load that does not particularly affect security, there is no need to send backup data.

With such backup data, the units U ₄ and U
_5, can continue their work without any conscious that the unit U ₃ failed.

Whereas a state of failure units U _3, there is a case where if the micro Konpyuta own state in which only the branch portion of the communication controller and the transmission line N can not only failed communication has failed.

In case of failure of only the part related to communication, unit U ₃
It easily recognizes that its own unit is isolated from the system from the absence of messages from other units, etc.
Operating the backup data output accessory O _23, O ₁₃ connected to the own unit U ₃ is prepared in advance in the own unit U _3.

If the microcomputer itself breaks down, the operation by another backup circuit is performed.

FIG. 5 is a diagram for explaining the operation when the monitoring unit U ₁ has failed. If the failure of only a part related to the communication, the monitoring unit U ₁ has itself can be the easily recognized since the communication with the other unit ceases being isolated from the system. The monitoring unit U ₁ has its own unit U ₁
The output connected accessory O _41, backup data of O ₅₁ prepared in advance in, it operates. If the microcomputer itself breaks down, the operation by another backup circuit is performed. Also, the unit U _2, U _3, since even after elapse of a predetermined time the transmission request message from the monitoring unit U ₁ does not come, can recognize that the monitoring unit U ₁ has failed. In this case, the units U ₂ , U ₃ are the output accessories O controlled by the message from the monitoring unit U _1.
12 and O ₁₃ are operated by the backup data prepared in advance. At the same time, the driver is warned of the occurrence of an abnormality.

Thus, according to the system of this embodiment, the unit U ₂ ~U ₅ other than the monitoring unit U _1, means for performing means for determining a own isolation and failure monitoring unit U _1, the treatment for it It is only necessary to provide a means for determining the failure of the other unit and a means for taking measures when the other unit fails.

Each unit U ₁ ~U ₅ described above can be configured as shown in for example Figure 6.

That is, the unit U in the _i, under load driving instruction signal from the input auxiliary I, to generate a message, the output accessory decodes the received message O for multiplex transmission
CPU 11 for driving the CPU is provided. This CPU11
Are connected to an input auxiliary device I and an output auxiliary device O via an input / output interface 12. The CPU 11 (or the communication controller 14 to be described later) is provided with an output terminal that is fixed at a high level during normal operation and falls to a low level when a failure occurs. Circuit 13 is connected. When the CPU 11 (or the communication controller 14) fails, the backup circuit 13 causes only the output auxiliary equipment O, which is indispensable for ensuring safety, to operate in the fixed operation mode among the output auxiliary equipment O.

A communication controller 14 that performs communication control is connected to the CPU 11. The communication controller 14 has a built-in memory for storing incoming received data and the like. This communication controller 14 is connected to the transmission line N.

Of the thus constructed unit U _i, the CPU11 of the monitoring unit U ₁ includes a program for monitoring whether regularly other units U ₂ ~U ₅ is operating normally, the failure unit And a program for transmitting the backup data in place of the program. Further, the CPU11 of the unit U ₂ ~U ₅ except monitoring unit, a program for diagnosing failure of the monitoring unit U ₁ is stored. Further, the CPU 11 of all the units U _{1 to} U ₅ stores a program for recognizing that the own unit is isolated from the system.

Next the operation of the configured units U _i as this.

In the monitoring unit U ₁ is the interval between the normal unit communication, executes the processing for monitoring the status of regular other units. This process is shown in FIG.

That is, the unit U ₂ to unit U ₅ in turn, transmits the data indicating a request for a response (S21). Then, it is determined whether or not each unit is operating normally from the presence or absence of the response (S22). If there is no response, that fact is registered (S23). Unit U ₂ if there is no response from only a portion of the unit U _j of ~U ₅ (S24,
S26), the unit U _j is judged to be faulty, and transmits the backup data with the monitoring unit U ₁ itself instead of the data held by the fault unit (S27). Further, if there is no response from all units U ₂ ~U ₅ (S24), and recognizes that the portion related to communication of the own unit U ₁ has failed, which is connected to the own unit U ₁ Output Auxiliary equipment O
₄₁ and _O51 are controlled by the backup data (S25).

On the other hand, in the unit U ₂ ~U ₅ other than the monitoring unit U ₁ may be determined self-isolated for example by processing as shown in FIG. 8.

That is, first, not come data such as response request from the monitoring unit U ₁ is sent during the predetermined time period, if the communication with the other unit capable determines that the monitoring unit U ₁ is faulty (S31 ), controlled by the output accessory O only backup data controlled by the data from the monitoring unit U ₁ (S34).

If there is no transmission from all units other than the monitoring unit for more than a certain period of time and there is no response to the transmission from the own unit, the unit is recognized as isolated and Output auxiliary equipment O connected
Among them, only the output auxiliary equipment O, which is indispensable for safety, is controlled by the backup data (S33).

By performing such processing, it is possible to standardize and simplify the program of the unit U ₂ ~U _5, it is possible to improve the cost and scalability of the entire system.

Although only one monitoring unit is provided in the above embodiment, for example, as shown in FIG.
By configuring U ₁ and U ₂ ′ as a monitoring unit, the reliability of the monitoring unit itself can be further improved. In this case, a program for diagnosing a failure of the monitoring unit in other units becomes unnecessary, and the program configuration of each unit can be further simplified.

[Effects of the Invention] As described above, according to the present invention, the monitoring unit monitors whether or not another unit is normal, and if a faulty unit is detected, backup data is sent instead of the faulty unit. Therefore, the means for diagnosing failures of units other than the monitoring unit can be simplified, the cost of the entire system can be reduced, and a system with excellent expandability can be provided. .

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a schematic configuration of a multiplex transmission system according to an embodiment of the present invention, FIG. 2 is a timing diagram showing a message at the time of monitoring a communication state in the system, and FIG. FIG. 4 is a schematic diagram showing the configuration, FIG. 4 is a schematic diagram for explaining an operation when a unit other than the monitoring unit has failed in the same system, and FIG. 5 is an explanation for an operation when the monitoring unit has failed in the same system. FIG. 6 is a block diagram showing a detailed configuration of each unit in the same system, FIG. 7 is a flowchart showing a communication state monitoring process of a monitoring unit in the same system, and FIG. 8 is other than a monitoring unit in the same system. FIG. 9 is a flow chart showing the self-diagnosis processing of the unit, FIG. 9 is a schematic diagram showing a schematic configuration of a multiplex transmission system according to another embodiment of the present invention, and FIG. Is a schematic diagram showing a schematic configuration of a conventional multiplex transmission system. U, U _{2 to} U ₅ … Unit, U ₁ , U ₂ ′… Specific unit, N
...... Transmission line, I, I ₁₂ , I ₁₃ , I ₂₃ , I ₂₄ , I ₃₄ , I ₃₅ , I ₄₁ , I ₄₅ , I
₅₁ , I ₅₂ …… input auxiliary equipment, O, O ₁₂ , O ₁₃ , O ₂₃ , O ₂₄ , O ₃₄ , O ₃₅ , O ₄₁ ,
O ₄₅ , O ₅₁ , O ₅₂ …… Output auxiliary equipment.

Continuation of the front page (72) Inventor Kazuo Enomoto 1-5-1, Kiba, Koto-ku, Tokyo Inside Fujikura Electric Wire Co., Ltd. (72) Inventor Kimitaka 1-5-1, Kiba, Koto-ku, Tokyo Inside Fujikura Electric Wire Co., Ltd. (72) Inventor Ken Sasaki 1-5-1, Kiba, Koto-ku, Tokyo Inside Fujikura Electric Wire Co., Ltd. (56) References JP-A-61-218243 (JP, A) JP-A-63-207753 (JP, A) JP-A-2-67841 (JP, A) JP-A-3-220041 (JP, A) JP-A-3-283843 (JP, A) JP-A-1-178161 (JP, U) JP-A-2-126241 (JP, U) Hikaru 3-6702 (JP, U) Fujikura Technical Report (No. 83), Kazuya Akashi et al. "Control of on-board electrical components by multiplex communication", pages. 68-77 (October 20, 1992) (58) Field surveyed (Int. Cl. ⁷ , DB name) H04L 12/28 B60R 16/02 JICST file (JOIS)

Claims (1)

(57) [Claims] 1. A plurality of units distributed in a vehicle,
An input auxiliary device and an output auxiliary device connected to these units, and a transmission line for coupling the units are provided. By performing multiplex transmission of messages between the units via the transmission line, the In the in-vehicle multiplex transmission system for controlling the driving of the output accessory based on a signal from the input accessory, a specific monitoring unit of the plurality of units monitors whether another unit is normal. Failure diagnosis means, and backup means for transmitting a backup message to another unit in place of the failed unit when a unit diagnosed as failure by the means exists. Characteristic multiplex transmission system for vehicles.