JP3088201B2 - 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, when the transmission / reception means of a certain control unit fails, even if the control unit returns to a normal state thereafter, the control unit is excluded. In general, multiplex communication is performed. However, as described above, once a failed control unit returns to a normal state and then performs multiplex communication by excluding the control unit, it is necessary for each control unit to perform control. There is a problem that control data to be used is reduced and control reliability is reduced.

[0005]

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.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to allow a controller of each control unit to store a data storage section for storing connection states of a plurality of control units, and to confirm that its own transmitting / receiving means has failed and has returned to a normal state. Self-diagnosis means capable of diagnosing; and a return means for performing a return operation for joining multiplex communication when the transmission / reception means returns to a normal state after a failure. This is achieved by the return means being configured to rewrite the connection state of the plurality of control units stored in the data storage unit in accordance with the control signal first received from the unit. In a preferred embodiment of the present invention, while the return means determines that the transmission / reception means has failed, the control unit leaves the multiplex communication and does not perform the operation of returning the control unit to the multiplex communication. It is configured as follows. In another preferred embodiment of the present invention, the control signal includes a reception connection confirmation signal area, and the return unit rewrites connection states of the plurality of control units according to the reception connection confirmation signal area of the control signal received first. It is configured as follows.

[0007]

According to the present invention, the controller of each control unit diagnoses the data storage section for storing the connection state of the plurality of control units and the fact that its own transmitting / receiving means has failed and has returned to the normal state. Since the self-diagnosis device includes a possible self-failure diagnosis means and a return means for performing a return operation for joining multiplex communication when the transmission / reception means recovers to a normal state after the failure, the control in which the transmission / reception means fails once If the unit subsequently returns to the normal state, it can participate in multiplex communication. At that time, at the time of the return operation, the transmitting / receiving unit receives the return signal according to the control signal first received from another control unit. Since the connection state of the plurality of control units stored in the data storage unit is rewritten, each control unit when returning to the normal state A connection state, and correctly recognized, it is possible to join the multiplex communication, it is possible to improve the reliability of the control.

[0008]

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 representing the start of the frame F. When each control unit receives this SD code, it recognizes the start of the frame F. 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 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 unit 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.

According to the status information, the self-diagnosis means 15 operates as follows.
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. 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 The self-diagnosis diagnosing unit 15 diagnoses that the transmission / reception unit 10 has failed. On the other hand, after the transmission / reception unit 10 has failed, the self-failure diagnosing unit 15 receives 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, and after the transmitting / receiving means 10 has failed, 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 return 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 self-diagnosis unit 15 of each control unit determines whether the transmission / reception unit 10 has failed as described above. as a result,
When the determination is YES, that is, when it is determined that the transmission / reception unit 10 has failed, the self-failure diagnosis unit 15 outputs a diagnosis signal including information to that effect to the return unit 16.

When the recovery means 16 receives a diagnostic signal from the self-failure diagnosing means 15 including information indicating that the transmitting / receiving means 10 has failed, it sets the flag J to 1 to indicate that it has left the multiplex communication. Is stored in the data storage unit 19, and thereafter, the self-failure diagnosing unit 15 again determines whether or not the transmitting / receiving unit 10 has failed. On the other hand, if NO, that is, if it is determined that the transmission / reception means 10 has not failed, the self-failure diagnosis means 15
Outputs a diagnostic signal including the information to that effect to the return unit 16.

When the return means 16 receives from the self-failure diagnosing means 15 a diagnostic signal including information indicating that the transmitting / receiving means 10 has not failed, it determines whether or not the flag J is "1". 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. Therefore, the return means 16 does not output any signal and returns again. The self-diagnosis unit 15 determines whether the transmission / reception unit 10 has failed.

On the other hand, if YES, the transmitting / receiving means 10 diagnosed as having failed in the previous cycle
However, in this cycle, it is recognized that the state has returned to the normal state. Therefore, the return unit 16 performs the return operation as described above, and the transmission / reception unit 10 sets the connection state of each control unit stored in the data storage unit 19 according to the control signal first received from another control unit. Is rewritten, and the flag J is set to 0 to return to the multiplex communication. After that, the self-diagnosis unit 15 again determines whether the transmission / reception unit 10 has failed.

According to this embodiment, the transmission / reception means 10
However, when the control unit that failed from the multiplex communication and returned to the normal state also returned to the multiplex communication, the reliability of the control could be improved, and the control unit returned to the normal state. Later, the transmission / reception means 10 rewrites the connection state of each control unit stored in the data storage unit 19 according to the control signal first received from another control unit. By recognizing the connection state of the unit, it is possible to participate in multiplex communication, and it is possible to increase the reliability of control.

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.

[0026]

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-1-303942 (JP, A) JP-A-58-213548 (JP, A) JP-A-58-222634 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H04L 12/28 H04Q 9/00

Claims (3)

(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 execute control, the controller of each control unit includes the plurality of control units .
A data storage unit for storing the connection state of the control unit, a self-failure diagnosing means capable of diagnosing that its own transmitting / receiving means has failed and has returned to a normal state, and having returned to a normal state after the transmitting / receiving means has failed And a return unit for performing a return operation for joining multiplex communication.In the return operation, the return unit stores the data in the data storage unit according to a control signal first received by the transmission / reception unit from another control unit. A multiplex communication device configured to rewrite a stored connection state of a plurality of control units. 2. The control device according to claim 1, wherein said control unit is configured to disconnect said control unit from multiplex communication and not to perform a return operation to multiplex communication while determining that said transmitting / receiving unit is out of order. The multiplex communication device according to claim 1, wherein 3. The control signal includes a reception connection confirmation signal area, and the return unit rewrites connection states of the plurality of control units according to a reception connection confirmation signal area of the first received control signal. The multiplex communication apparatus according to claim 1, wherein the multiplex communication apparatus is configured as follows.