JP3088200B2 - Multiplex communication device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiplex communication apparatus for performing communication between various electric components in a vehicle or the like, and more particularly, to a multiplex communication apparatus provided with a transmission / reception means and a controller on a common multiplex communication line. And a multiplex communication apparatus that connects the control units and transmits signals between the control units.

[0002]

2. Description of the Related Art With the development of electronic control technology, recent automobiles are equipped with a remarkably large number of electronic devices. As a result, the number of wirings connecting the electronic devices increases significantly and the wiring becomes complicated. There was a problem of becoming. Therefore, in order to reduce the number of wirings and simplify the wirings, a plurality of control units each including a transmission / reception unit and a controller are connected to a common multiplex communication line by a node, and the control units are connected to each other. A multiplex communication device for transmitting a signal has been proposed.
224534 publication).

In such a multiplex communication apparatus, when a transmission / reception means of a certain control unit fails, no signal is sent from the control unit to a common multiplex communication line. , The control unit can be recognized as having failed, and multiplex communication is performed only with another control unit.

[0004]

In the multiplex communication apparatus configured as described above, in order to improve the reliability of control,
Once the failed control unit returns to a normal state, the control unit sends a normal return signal indicating that the control unit has returned to normal to the multiplex communication line, and responds to the normal return signal to perform another control. When a response signal is received from the unit,
It is conceivable that the control unit again transmits a normality return signal to the multiplex communication line so as to participate in the multiplex communication.

[0005] However, after the failure, the normal state may be restored, but the frequent failure means that the control unit itself may have some defect. However, there is a problem in that when a control unit which is poor in reliability and which often fails because it returns to a normal state participates in multiplex communication, the reliability of control is rather lowered.

[0006]

An object of the present invention is to provide a multiplex communication line which is connected to a common multiplex communication line by a node, has a controller and transmission / reception means, and can output a signal including control data to the multiplex communication line. In a multiplex communication device including a plurality of control units configured to receive a signal including control data from a communication line and configured to execute control,
It is an object of the present invention to provide a multiplex communication device capable of improving control reliability.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a self-diagnosis means for a controller of each of the control units, the self-diagnosis means being capable of diagnosing that its own transmission / reception means has failed and has returned to a normal state. When it is determined by the means that the transmitting / receiving means has failed, the transmitting / receiving means is disconnected from the multiplex communication and the reconnection operation is not performed. Return means for performing a reconnection operation of the transmission / reception means in order to join the transmission / reception means. This is achieved by that the return means is configured not to execute the reconnection operation even when it is determined that the connection has been restored. According to a preferred embodiment of the present invention, the controller of each control unit has a data storage unit for storing data indicating a connection state of another control unit, and the self-diagnosis unit includes a data storage unit. If the stored data does not match the reception connection confirmation signal received by the transmission / reception means, the transmission / reception means is diagnosed as having a failure. Thereafter, if the two match, the transmission / reception means has returned to a normal state. It is configured to diagnose. According to another preferred embodiment of the present invention, the transmission / reception unit stores status information indicating its own state, and the controller of each control unit resets the status information stored in the transmission / reception unit. In addition, the failure diagnosis unit is configured to diagnose a failure of the transmission / reception unit based on whether the status information becomes a predetermined value within a predetermined time. According to still another preferred embodiment of the present invention, the self-failure diagnosing unit receives status information indicating a state of the transmitting / receiving unit from the transmitting / receiving unit, and the controller transmits a frame signal to the transmitting / receiving unit. Or, when the controller receives a frame-like signal from the transmission / reception signal, the controller diagnoses a failure of the transmission / reception means based on the status information. According to still another preferred embodiment of the present invention, when the self-failure diagnosing unit determines that the transmitting / receiving unit has returned to a normal state, the returning unit outputs a normal return signal to a multiplex communication line. It is configured to participate in multiplex communication after the response signal of the normal return signal is received from another control unit.

[0008]

According to the present invention, the controller of each control unit is capable of diagnosing that its own transmission / reception means has failed and has returned to a normal state. When it is determined that the transmission / reception means has failed, the transmission / reception means is disconnected from the multiplex communication and the reconnection operation is not performed. Return means for performing a reconnection operation, when the self-failure diagnosing means determines that the transmission / reception means has failed a predetermined number of times during multiplex communication, and thereafter determines that it has returned to a normal state. Also, since the return means is configured not to perform the reconnection operation, the control unit which often fails and there is a possibility that the transmission / reception means itself may have some defect. , Even if return k to a normal state, not applied to the multiplex communication. As a result, it is possible to prevent the failed control unit itself from hindering communication with another control unit, thereby improving control reliability.

[0009]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a network diagram of a multiplex communication device according to an embodiment of the present invention. In FIG. 1, a multiplex communication device according to an embodiment of the present invention includes a tire including an engine control unit 1 for controlling an engine, an anti-skid braking system (hereinafter referred to as ABS), and a traction control system. And a 4WS control unit 3 for performing a steering angle control of each wheel, and a body control unit 4 for performing control of body switches. These four control units are nodes 5, 6, 7,
8 is connected to a loop-shaped common multiplex communication line 9. Each control unit includes a controller and transmission / reception means (not shown).

The engine control unit 1, the slip control unit 2, the 4WS control unit 3 and the body control unit 4 transmit signals to the multiplex communication line 9 via the nodes 5, 6, 7, and 8, respectively. , A signal is received from the multiplex communication line 9 via the nodes 5, 6, 7, and 8, and a predetermined control is performed. As described above, the engine control unit 1, the slip control unit 2, the 4WS control unit 3, and the body control unit 4 transmit signals to the multiplex communication line 9 via the nodes 5, 6, 7, and 8, respectively. At the same time, since signals are received from the multiplex communication line 9 via the nodes 5, 6, 7, and 8, in order to prevent collision of signals on the common multiplex communication line 9, in this embodiment, CSMA / CD- The AMP method is adopted. Here, CSMA (Carrier Sense
Multiple Access) refers to a method in which each control unit transmits a signal to the multiplex communication line 9 after confirming the availability of the multiplex communication line 9. CD (Collision Detection) refers to a method in which each control unit A method of monitoring a transmission signal on the communication line 9 and detecting a collision of the transmitted signal when the collision of the transmitted signal is detected, refers to an AMP (Arbitration on Message P).
The term “riority” refers to a method of transmitting a high-priority signal as it is without destruction at the time of signal collision. A signal transmitted by each control unit is composed of a frame, and a signal transmitted by a certain control unit is configured to be received by all other control units.

FIG. 2 shows a configuration of a signal transmitted by each control unit. As shown in FIG. 2, the signal transmitted by each control unit is a frame-like signal and ACK.
Field (receiving connection confirmation signal area)
The frame F of the frame-like signal has an SD (Start Delimite).
r) Code, PI (Briority) code, ID code, data length, data 1 to data N, and check code.

The SD code is a code indicating the start of the frame F, and each control unit recognizes the start of the frame F when receiving the SD code. The PI code indicates that the multiple control units have transmitted signals to the multiplex communication line 9 at the same time,
In this case, when a signal collision occurs, which signal is to be processed preferentially. In this embodiment,
In the multiplex communication line 9, the low level is wired or (WI
RED-OR), so the one with the lower bit value is given priority. When a signal collision occurs on the multiplex communication line 9, the PI code of the control unit with the higher priority remains on the multiplex communication line 9, and the PI code of the control unit with the lower priority becomes the control code of the higher priority. The lower priority control unit thereby detects that the transmitted signal has collided and has not been received by the other control unit, since it can be converted to the PI code of the unit, and transmits the signal again. It is configured as follows. The ID code is a code indicating the control unit of the transmission source. The number of subsequent data is written in the data length, and N
When there are pieces of data, the data length is N. Upon receiving this signal, the control unit reads the data following the data length as much as the data length. In data 1 to data N, various data to be transmitted are written by the signals. The check code causes the control unit that has received the frame-like signal to confirm the end of the frame-like signal and, at the time of reception, checks whether or not the frame-like signal has been received, as desired. .

Each control unit transmits an ACK field following transmission of the frame signal. The ACK field is composed of bits equal to the number of control units connected to the multiplex communication line 9, and each control unit is assigned a predetermined unique bit area. In the present embodiment, since four control units are connected to the multiplex communication line 9, the ACK field is composed of 4 bits, which are respectively the engine control unit 1, the slip control unit 2, the 4WS control unit 3, and the body. A unique bit area is assigned to the system control unit 4. Each control unit confirms whether or not the frame signal has been normally received by using each bit area of the ACK field. That is, the control unit that transmits the frame-like signal transmits the ACK field to the multiplex communication line 9 after setting the bit area to “0” following the transmission of the frame-like signal. The control unit that receives the frame-like signal checks whether there is an error in the contents of the data 1 to data N of the frame-like signal using the check code of the frame-like signal. A reception connection confirmation signal (ACK signal) is transmitted to a predetermined unique bit area for the unit,
Write "1".

Thus, when the frame-like signal transmitted from a certain control unit is normally received by all the other control units, each bit area of the ACK field on the multiplex communication line 9 is set to "1". On the other hand, when any of the control units does not normally receive the frame signal, the bit area unique to the control unit remains “0”. Therefore, by receiving the ACK field, the control unit that has transmitted the frame-like signal can check whether or not another control unit has normally received the frame-like signal. When there is a control unit, the frame signal is transmitted again.

FIG. 3 is a block diagram of each control unit. In FIG. 3, each control unit includes a transmission / reception unit 10 and a controller 11.
Self-failure diagnosis means 1 for diagnosing whether the state has returned to a normal state
5. Based on the signal from the transmission / reception means 10, once the failed transmission / reception means 10 has returned to a normal state, it returns to the multiplex communication line 9 to the return means 16 for performing a return operation for joining the multiplex communication again. A signal transmission unit 17 for transmitting a frame-like signal to be transmitted to the transmission / reception means 10;
0 is a signal receiving unit 1 for receiving a received frame signal.
8. Control based on detection signals input from a data storage unit 19 that stores data included in a frame-like signal received from another control unit via a multiplex communication line 9 and various sensors (not shown). A control unit 20 is provided for generating a signal, outputting the signal to the signal transmission unit 17, and generating a drive signal in accordance with the reception signal input from the signal reception unit 18 and outputting the drive signal to various actuators (not shown). Have been. When transmitting the frame signal to the transmission / reception means 10, the signal transmission section 17 outputs a transmission completion signal to the self-failure diagnosis means 15, and the signal reception section 18 receives the frame signal from the transmission / reception means 10. Then, a reception completion signal is output to the self-failure diagnosing means 15.
It is configured to output a diagnostic signal including diagnostic information as to whether the device has failed or has returned to the normal state, to the return means 16. The return means 16 is provided with a counter (not shown).

The transmission / reception means 10 receives a signal to be transmitted to another control unit from the signal transmission section 17 of the controller 11 via the multiplex communication line 9 and transmits the multiplex communication line 9 from the other control unit. Then, the received frame-like signal is output to the signal receiving unit of the controller 11. Further, the transmitting and receiving means 10 outputs the received frame-like signal to the signal receiving unit of the controller 11 when
The status information indicating the state of the transmission / reception means 10 itself is output to the self-failure diagnosis means 15 of the controller 11. The status information includes an error bit to which an error is written when the check code checks that the frame-like signal has not been received as desired, a signal received from the multiplex communication line 9, The signal received from the multiplex communication line 9 is not transmitted to the signal receiver 18 of FIG.
The transmitting and receiving means 10 is connected to the signal receiving unit 18 of the controller 11.
After transmission to the multiplex communication line 9, the reception bit set to 1 and the signal received by the transmission / reception means 10 from the signal transmission unit 17 are transmitted to the multiplex communication line 9; The signal received by the transmission / reception means 10 from the signal transmission unit 17 has not yet been transmitted to the multiplex communication line 9 and is set to 1 when the data contained in the signal cannot be written. It consists of a write bit.

In accordance with this status information, the self-failure diagnosing means 15 makes the transmission / reception means 10
Can be diagnosed as having failed or has returned to a normal state. That is, first, when an error is written in the error bit of the status information read by the self-failure diagnosis means 15, the transmission / reception means 10 receives the frame signal from the multiplex communication line 9 as desired. Therefore, the self-diagnosis unit diagnoses that the transmission / reception unit 10 has failed. Further, even when no error is written in the error bit of the status information, when the self-failure diagnosing unit 15 receives the reception completion signal from the signal receiving unit 18, it transmits and receives the signal received from the multiplex communication line 9. Since the means 10 is transmitting to the signal receiving section 18 of the controller 11, immediately after that, if the received bit of the status information read from the transmitting / receiving means 10 is 0, the self-failure diagnosing means 15 is 10 is diagnosed as having failed, while the self-failure diagnosing means 15 immediately after receiving the reception completion signal from the signal receiving section 18 after the transmission / reception means 10 has failed, reads the status information read from the transmission / reception means 10. When the received bit is 1, the self-failure diagnosis means 15 diagnoses that the transmission / reception means 10 has returned to a normal state. Further, when the self-failure diagnosing unit 15 receives the transmission completion signal from the signal transmitting unit 17, the signal is transmitted to the transmitting / receiving unit 10 and further writing of data should not be possible. And transmission / reception means 10
When the write bit of the status information read from is 0, the self-failure diagnosing means 15 diagnoses that the transmitting / receiving means 10 has failed, while the self-failure diagnosing means 15 If the write bit of the status information read from the transmission / reception means 10 is 1 immediately after receiving the transmission completion signal from the signal transmission unit 17, the self-failure diagnosis means 15 diagnoses that the transmission / reception means 10 has returned to a normal state. .

The self-failure diagnosing means 15 indicates the value of each bit area of the ACK field of the frame-like signal received by the signal receiving section 18 and the connection state of another control unit stored in the data storage section 19. Compare with the data,
If there is an inconsistency between the two, the transmission / reception means 10 is diagnosed as having a failure. On the other hand, if the transmission / reception means 10 has failed and the two have become identical, the self-failure diagnosis means 15 It is diagnosed that the transmitting / receiving means 10 has returned to the normal state.

When the self-diagnosis unit 15 determines that the transmission / reception unit 10 has returned to the normal state based on the diagnostic signal input from the self-diagnosis unit 15, the recovery unit 16 sends a normal recovery signal to the transmission / reception unit 10. And outputs it to the multiplex communication line 9. When receiving the normal return signal, the other control unit transmits a response signal to the multiplex communication line 9 and causes the transmission / reception unit 10 of the control unit that has transmitted the normal return signal to receive the response signal. The transmission / reception means 10 having received the response signal transmits the response signal to the return means 16 and
6 receives the response signal, returns the normal return signal again,
The signal is output to the multiplex communication line 9 and again participates in the multiplex communication.

FIG. 4 is a flow chart showing a fault diagnosis and recovery operation performed in each control unit during multiplex communication. In FIG. 4, first, the return means 16 of each control unit is provided with a counter value N of a counter (not shown).
Is set to 0. Next, the self-failure diagnosis means 15 of each control unit determines whether or not the transmission / reception means 10 has failed as described above.

As a result, when the result is YES, that is, when it is determined that the transmitting / receiving means 10 has failed, the self-failure diagnosing means 15 outputs a diagnostic signal including information to that effect to the returning means 16. When receiving a diagnostic signal including information indicating that the transmitting / receiving means 10 has failed from the self-failure diagnosing means 15, the return means 16 increases the counter value N of the counter to N + 1 and sets the flag J to 1. Then, the multiplex communication is separated from the multiplex communication, and the fact is stored in the data storage unit 19, and the self-failure diagnosing unit 15 determines again whether the transmitting / receiving unit 10 is out of order.

On the other hand, when the result is NO, that is, when it is determined that the transmitting / receiving means 10 has not failed, the self-failure diagnosing means 15 outputs a diagnostic signal including information to that effect.
Output to the return means 16. When receiving a diagnostic signal including information that the transmitting / receiving means 10 has not failed from the self-failure diagnosing means 15, the return means 16 determines whether the flag J is 1 or not.

As a result, when the result is NO, the transmission / reception means 10 is normal even in the previous cycle, and multiplex communication may be continued as usual.
No signal is output, and the self-diagnosis unit 15 again determines whether the transmission / reception unit 10 has failed. On the other hand, when YES, it is recognized that the transmission / reception means 10 diagnosed as having failed in the previous cycle has returned to the normal state in the current cycle,
The return unit 16 further determines whether the counter value N of the counter is equal to a predetermined value No, for example, 6. The counter value N indicates how many failures have occurred since the transmission / reception means 10 of the control unit started multiplex communication. Therefore, when this determination result is YES,
This indicates that the number of failures has reached No, and has often returned to a normal state after a failure, and the control unit itself has returned to a normal state since there is a high possibility that some defect has occurred. However, the return to the multiplex communication may rather reduce the reliability of the control. Therefore, the return unit 16 leaves the multiplex communication without performing the return operation, and to that effect, The data is stored in the data storage unit 19 and the communication with another control unit is terminated.

On the other hand, when the result is NO, that is, when the number of failures of the transmission / reception means 10 of the control unit has not reached No, the possibility that the control unit itself is defective is still unknown. Since it is not high, and it is desirable to return to the multiplex communication in order to enhance the reliability of the control, the return unit 16 performs the return operation, sets the flag J to 0, and receives the signal by the transmission / reception unit 10. The connection state of each control unit is stored in the data storage unit 19.
And return to the multiplex communication. After that, the self-diagnosis unit 15 again determines whether the transmission / reception unit 10 has failed.

According to the present embodiment, once the transmission / reception means 10
When the control unit that has failed and has departed from the multiplex communication also returns to the normal state, the control unit is returned to the multiplex communication, so that the reliability of control can be improved. Since the control unit that has failed the number of times and is likely to have some defect in the control unit itself is separated from the multiplex communication even after returning to the normal state, the control reliability is further improved. It is possible to increase.

The present invention is not limited to the embodiments described above, and various changes can be made within the scope of the invention described in the claims, which are also included in the scope of the present invention. Needless to say, For example, in addition to or instead of the failure diagnosis method by the self-failure diagnosis unit 15 in the above-described embodiment, the controller 11
A terminal capable of resetting the status information stored in the transmission / reception means 10 so that the reception bit or the write bit is reset to a predetermined value within a predetermined time after resetting the reception bit or the write bit of the status information. The failure of the transmission / reception means 10 can also be determined based on whether or not the failure occurs.

In the above embodiment, the four control units of the engine control unit 1, the slip control unit 2, the 4WS control unit 3 and the body control unit 4 are connected to the multiplex communication line 9. In place of all or part of, or in addition to,
Other control units may be connected. Further, in the present invention, each means does not necessarily mean a physical means, and the present invention includes a case where the function of each means is realized by software, and the function of one means is two or more. If implemented by physical means,
The present invention also includes a case where the functions of the above means are realized by one physical means.

[0028]

According to the present invention, each of the nodes is connected to a common multiplex communication line by a node and includes a controller and transmission / reception means, and a signal including control data can be output to the multiplex communication line. Provided is a multiplex communication device including a plurality of control units configured to execute a control by receiving a signal including control data from the multiplex communication line and to improve the reliability of the control. It becomes possible to do.

[Brief description of the drawings]

FIG. 1 is a network diagram of a multiplex communication device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration of a signal transmitted by each control unit.

FIG. 3 is a block diagram of each control unit.

FIG. 4 is a flowchart illustrating a failure diagnosis and a return operation performed in each control unit during multiplex communication.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 engine control unit 2 slip control unit 3 4WS control unit 4 body system control unit 5, 6, 7, 8 node 9 multiplex communication line 10 transmitting / receiving means 11 controller 15 self-failure diagnosis means 16 return means 17 signal transmission section 18 signal reception section 19 data storage unit 20 control unit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-263346 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 12/28 H04Q 9/00 H04L 29 / 14

Claims (5)

(57) [Claims] 1. A multiplex communication line connected to a common multiplex communication line by a node, comprising a controller and transmission / reception means, capable of outputting a signal including control data to the multiplex communication line, and controlling from the multiplex communication line. In a multiplex communication device including a plurality of control units configured to receive a signal including data and configured to be able to execute control, the controller of each of the control units is configured such that its own transmission / reception unit has failed and is in a normal state. Self-failure diagnosing means capable of diagnosing the return, and when it is determined by the self-failure diagnosing means that the transmitting / receiving means has failed, the transmitting / receiving means is disconnected from multiplex communication and the reconnection operation is not performed, Thereafter, when it is determined that the state has returned to the normal state, a reconnection operation of the transmission / reception means is performed to join multiplex communication. Return means, the self-failure diagnosing means determines that the transmission / reception means has failed a predetermined number of times during the multiplex communication, and also determines that the transmission / reception means has returned to a normal state thereafter. A multiplex communication device characterized in that the means is configured not to perform the reconnection operation. 2. The controller of each of the control units has a data storage unit for storing data indicating a connection state of another control unit, and the self-failure diagnosing unit stores the data stored in the data storage unit and When the reception connection confirmation signal received by the transmission / reception unit does not match, the transmission / reception unit is diagnosed as having a failure, and when both match, it is diagnosed that the transmission / reception unit has returned to a normal state. The multiplex communication device according to claim 1, wherein 3. The transmission / reception unit stores status information indicating its own state. The controller of each of the control units resets the status information stored in the transmission / reception unit and the failure diagnosis unit. Is
2. The multiplex communication apparatus according to claim 1, wherein a failure of said transmission / reception means is diagnosed based on whether said status information becomes a predetermined value within a predetermined time. 4. The self-failure diagnosing means receives status information indicating the state of the transmitting / receiving means from the transmitting / receiving means, and when the controller transmits a frame-like signal to the transmitting / receiving means, or 2. The multiplex communication apparatus according to claim 1, wherein when a frame-like signal is received from the transmission / reception signal, a failure of said transmission / reception means is diagnosed based on said status information. 5. The return means outputs a normal return signal to a multiplex communication line when the self-failure diagnosis means determines that the transmission / reception means has returned to a normal state, and outputs a response signal to the normal return signal. The multiplex communication device according to claim 1, wherein the multiplex communication device is configured to participate in multiplex communication after being received from another control unit.