JPH0630005A - Multiplex communication equipment - Google Patents

Abstract

PURPOSE:To improve the control reliability of a multiple communication equipment by making this equipment join the communication when the control unit that could not output a connection answer signal within a prescribed time outputs a multiplex communication start signal and then a control signal is received from another control unit. CONSTITUTION:When the connection confirming signal is transmitted to a multiplex communication line 9, this signal is received by a body system control unit 4, a 4WS control unit 3, and a slip control unit 2 which are connected to the line 9. Then these units out put the received connection confirming signal to the line 9 respectively as soon as the start of a controller is complete. If a unit 1 receives an answer signal within a prescribed time after the unit 1 transmitted the confirming signal, the unit 1 decides that the units 4, 3 and 2 are connected to the line 9. If any control unit could not receive the confirming signal from the unit 1 nor output an answer signal within a prescribed time, a fact that the units 4, 3 and 2 are not connected to the line 9 is decided and the multiplex communication is started between the control unit and the unit 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiplex communication device for performing communication between various electric components in a vehicle or the like, and more specifically to a plurality of controls provided with transmitting / receiving means on a common multiplex communication line. The present invention relates to a multiplex communication device in which units are connected and signals are transmitted and received between control units.

[0002]

2. Description of the Related Art With the development of electronic control technology, automobiles of recent years are equipped with a remarkably large number of electronic devices. As a result, the number of wirings connecting the respective electronic devices is significantly increased and the wirings are 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 having a controller and a transmitting / receiving means are connected to a common multiplex communication line by a node, and each control unit is connected. There has been proposed a multiplex communication device configured to transmit and receive signals between them (for example, Japanese Patent Laid-Open No. 61-224534).

In such a multiplex communication device, before a plurality of control units reach a multiplex communication control state in which they send and receive signals to and from each other through a common transmission line, the controller of a predetermined control unit is A connection confirmation signal for requesting a response as to whether or not it is connected to a common multiplex communication line is sent to the multiplex communication line via the transmitting / receiving means, and a connection response signal is sent within a predetermined time in response to this connection confirmation signal. Only the control unit that has output is connected to the common multiplex communication line, and it is determined that multiplex communication is possible, and the multiplex including the information indicating which control unit is connected to the common multiplex communication line. It is configured to output a communication start signal and then shift to the multiplex communication control state. Therefore, the start-up of the controller is not completed within a predetermined time and the connection response signal is output. Control unit bets is not possible, then, even if the activation of the controller is completed, it is impossible to participate in the multiplex communication.

[0004]

However, in this way, even though there is no failure, the controller startup is not completed within a predetermined time, and a certain control unit is excluded, Performing multiplex communication means that the control data from the control unit cannot be received, and the data for control becomes insufficient, which causes a problem that desired control cannot be performed. .

[0005]

It is an object of the present invention that a plurality of control units each having a controller and a transmitting / receiving means are connected to a common multiplex communication line, and the multiplex communication lines are connected to each other through the multiplex communication line.
It is configured to be capable of transmitting and receiving signals, and obtains a response as to whether or not a predetermined control unit is connected to the multiplex communication line before reaching a multiplex communication state in which multiple control units transmit and receive each other. Only the control unit that outputs a connection confirmation signal to another control unit and outputs a response signal to the predetermined control unit within a predetermined time in response to the connection confirmation signal is connected to the common multiplex communication line. Therefore, it is determined that multiplex communication is possible and, after the connection confirmation signal is output, the multiplex including the information indicating which control unit is connected to the common multiplex communication line after the lapse of the predetermined time. In a multiplex communication device configured to output a communication start signal to the multiplex communication line to start multiplex communication, start multiplex communication without outputting a connection response signal within a predetermined time. The control unit that could not participate in the multiplex communication because of the output of the signal can also participate in the multiplex communication after the start of the multiplex communication, and the necessary and sufficient data for control is sent between the control units. It is an object of the present invention to provide a multiplex communication device capable of transmitting and receiving and improving control reliability.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to allow a control unit that has not been able to output a connection response signal within the predetermined period of time to another after the predetermined control unit outputs a multiplex communication start signal. It is achieved by being configured to participate in multiplex communication when receiving a control signal from the control unit.

[0007] In a preferred aspect of the present invention, the control unit that cannot output the connection response signal within the predetermined time period, the predetermined control unit outputs the multiplex communication start signal, and then the It is configured to participate in the multiplex communication after receiving a control signal from a predetermined control unit. In a further preferred aspect of the present invention, the control unit that has not been able to output the connection response signal within the predetermined time period is controlled by another control unit after the predetermined control unit outputs the multiplex communication start signal. After receiving the control signal from the unit, on the multiplex communication line,
It is configured to output a connection notification signal and participate in multiplex communication when a response signal is input to the connection notification signal from another control unit.

In still another preferred embodiment of the present invention, the control unit that cannot output the connection response signal within the predetermined time, and the predetermined control unit outputs the multiplex communication start signal. After that, after receiving the control signal from the predetermined control unit, the connection notification signal is output, and when the response signal is input to the connection notification signal from another control unit, it is added to the multiplex communication. Is configured.

[0009]

According to the present invention, the connection response signal cannot be output within a predetermined time, and when the multiplex communication is started, the multiplex communication with another control unit cannot be performed. After the start of multiplex communication, the unit can also perform multiplex communication with other control units, so necessary and sufficient data for control can be sent and received between each control unit to control it. It is possible to provide a multiplex communication device capable of improving the reliability of.

[0010]

Embodiments of the present invention will be described in detail below 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. 1, a multiplex communication apparatus according to an embodiment of the present invention is a tire including an engine control unit 1 that executes engine control, an anti-skid braking system (hereinafter referred to as ABS), and a traction control system. 4 control units including a slip control unit 2 for executing the slip control, a 4WS control unit 3 for executing the steering angle control of each wheel, and a body system control unit 4 for executing the control of body switches, These four control units consist of nodes 5, 6, 7,
8 connects to a common multiplex communication line 9 in a loop. Each control unit includes a controller and a transmitting / receiving means (not shown).

The engine control unit 1, the slip control unit 2, the 4WS control unit 3 and the body system control unit 4 send signals to the multiplex communication line 9 via the nodes 5, 6, 7 and 8, respectively. Further, although the signal is received from the multiplex communication line 9 via the nodes 5, 6, 7, and 8, in order to prevent the signal collision on the common multiplex communication line 9, in this embodiment, the CSMA / CD is used. -AMP
The method is adopted. Here, CSMA (Carrier Sens
e Multiple Access) is a method in which each control unit confirms the vacancy of the multiplex communication line 9 and then transmits a signal to the multiplex communication line 9, and CD (Collision Detection) means that each control unit Monitoring the transmission signal on the multiplex communication line 9,
When the collision of the transmitted signal is detected, the method to retransmit the signal is called AMP (Arbitration on Message).
Priority) refers to a method in which when a signal collides, a signal with high priority is transmitted as it is without being destroyed. Also, the signal transmitted by each control unit consists of a frame, and the signal transmitted by a certain control unit is
All other control units are configured to receive.

FIG. 2 shows a structure of a signal transmitted by each control unit. As shown in FIG. 2, the signal transmitted by each control unit is a frame-shaped signal and an ACK.
It consists of a field (reception connection confirmation signal area),
The frame F of the frame-like signal is SD (Start Delimite
r) code, PI (brity) 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 is transmitted to the multiplex communication line 9 by the plurality of control units at the same time.
Then, when a signal collision occurs, which signal is to be preferentially processed is instructed. In this embodiment,
In the multiplex communication line 9, the low level is wired or (WI
Since it is (RED-OR), the one with the lower bit value is given priority. When a signal collision occurs in the multiplex communication line 9, the PI code of the control unit with a high priority remains in the multiplex communication line 9, and the PI code of the control unit with a low priority has a high priority. Since it is changed to the PI code of the unit, the low priority control unit detects that the transmitted signal has collided and is not received by another control unit, and retransmits the signal. Is configured. The ID code is a code representing the control unit of the transmission source. In the data length, the number of data following this is written and N
When there are data items, the data length is N. The control unit which receives this signal reads the data following the data length by the amount corresponding to the data length. Various data to be transmitted are written in the data 1 to the data N by the signal. The check code causes the control unit that has received the frame-shaped signal to confirm that it is the end of the frame-shaped signal.

Each control unit transmits an ACK field following the transmission of the framed signal. The ACK field consists of bits equal to the number of control units connected to the multiplex communication line 9, and a predetermined unique bit area is assigned to each control unit. In this embodiment, since four control units are connected to the multiplex communication line 9, the ACK field consists of 4 bits, and the engine control unit 1, the slip control unit 2, the 4WS control unit 3 and the body, respectively. A unique bit area is assigned to the system control unit 4. Each control unit is configured to confirm whether or not the frame-shaped signal is normally received by each bit area of the ACK field. That is, the control unit that transmits the frame-shaped signal transmits the ACK field to the multiplex communication line 9 after transmitting the frame-shaped signal, with each bit area of the ACK field set to “0”. The control unit that receives the frame-shaped signal checks whether or not there is an error in the contents of the data 1 to data N of the frame-shaped signal based on the check code of the frame-shaped signal. If there is no error, another control unit is notified. On the other hand, in a predetermined unique bit area,
A reception connection confirmation signal (ACK signal) is transmitted and "1" is written.

Thus, when the frame-shaped signal transmitted from a certain control unit is normally received by all the other control units, all the bit areas of the ACK field on the multiplex communication line 9 are all set to "1". On the other hand, when one of the control units does not normally receive the frame-like signal, the unique bit area of the control unit remains "0". Therefore, by receiving the ACK field, the control unit that has transmitted the frame-shaped signal can confirm whether or not the other control unit has normally received the frame-shaped signal, and the control unit has not normally received the frame-shaped signal. When the control unit is present, the frame-like signal is retransmitted.

In the multiplex communication apparatus according to this embodiment, the type of the control unit connected to the multiplex communication line 9 is confirmed before the multiplex communication is started, and after the confirmation is completed, the multiplex communication is started. It The type of control unit connected to the multiplex communication line 9 is confirmed by the engine control unit 1 in this embodiment. That is, a connection confirmation signal is transmitted from the engine control unit 1 to the multiplex communication line 9, and the engine control unit 1 responds to this connection confirmation signal within a predetermined time t1 by the slip control unit 2, 4WS control unit 3, and The engine control unit 1 confirms the type of the control unit connected to the multiplex communication line 9 depending on whether or not the connection response signal is received from the body system control unit 4.

FIG. 3 is a time chart showing the output of signals from each control unit. In FIG. 3, when an ignition switch (not shown) is turned on, activation of the controller of each control unit is started. When it is determined that the predetermined condition is satisfied, for example, when the engine speed reaches 500 rpm, the engine control unit 1 sends the connection confirmation signal F1 to the multiplex communication line 9.

Thus, when the connection confirmation signal is sent to the multiplex communication line 9, the body system control units 4, 4WS control unit 3 and slip control unit 2 connected to the multiplex communication line 9 receive the connection confirmation signal. Then, as soon as the controller has been activated, the connection response signals F2, F3, F4
Are output to the multiplex communication line 9, respectively. As a result, as shown in FIG. 3, when the engine control unit 1 receives the connection response signal within a predetermined time t1 after transmitting the connection confirmation signal F1 to the multiplex communication line 9, the engine control unit 1 No. 1 determines that the body system control units 4, 4WS control unit 3 and the slip control unit 2 are connected to the multiplex communication line 9, and when a predetermined time t1 has elapsed, the body system control units 4, 4WS. The control unit 3 and the slip control unit 2 are
The multiplex communication start signal F5 including the connection information indicating that the multiplex communication line 9 is connected to the multiplex communication line 9 is transmitted.

When the body system control unit 4, 4WS control unit 3 and slip control unit 2 receive this multiplex communication start signal F5, they store connection information and multiplex communication is started. In this embodiment, CSMA / CD
The AMP system is adopted, and as shown in FIG. 3, each control unit periodically sends a refresh signal containing data stored in itself to the multiplex communication line 9 at intervals of a predetermined time ΔT. Although not shown in the figure, when the data stored in self changes,
In order to inform other control units of changes in data,
Each time, an event signal is transmitted to the multiplex communication line 9, and when an alternate communication request signal periodically output from another control unit is input, an alternate communication signal with a short period is output for a predetermined time. Is configured.

As described above, prior to the start of multiplex communication, the engine control unit 1 outputs the connection confirmation signal F1 and, within a predetermined time t1, the body system control unit 4, 4WS control unit 3 and slip When the connection response signals F2, F3, and F4 are received from the control unit 2, the engine control unit 1 determines that all the control units are connected to the multiplex communication line 9, and notifies that fact. A multiplex communication start signal F5 including information is output to the multiplex communication line 9, and multiplex communication is started among the engine control unit 1, the slip control unit 2, the 4WS control unit 3 and the body system control unit 4. On the contrary,
If there is a control unit that cannot receive the connection confirmation signal F1 from the engine control unit 1 and cannot output the connection response signal within a predetermined time t1 due to a delay in starting the controller, The engine control unit 1 determines that the control unit is not connected to the multiplex communication line 9, and outputs the multiplex communication start signal F5 including information to that effect to the multiplex communication line 9 for a predetermined time t1.
Multiplex communication is started between the control unit that has received the connection response signal and the engine control unit 1.

Conventionally, after the multiplex communication is started in this way, the connection confirmation signal F1 from the engine control unit 1 cannot be received and the connection response signal cannot be output even within the predetermined time t1. Even if the controller of the control unit subsequently starts up normally and is ready to output data for control, the control unit will no longer perform multiplex communication with other control units. Cannot be participated in, and thus the other control units will not be provided with sufficient data for control, and the control performed by each control unit will be unreliable. there were.

Therefore, in the present embodiment, in order to solve such a problem, the multiplex communication device, within a predetermined time t1,
The control unit that could not receive the connection confirmation signal F1 from the engine control unit 1 and could not output the connection response signal also outputs the multiplex communication start signal F5 from the engine control unit 1 unless there is an abnormality in it. When the control signal including the control data is received from the other control unit after the multiplex communication is started with the other control unit, it is possible to participate in the multiple communication with the other control unit. So that the slip control unit 2, 4W
An S control unit 3 and a body system control unit 4 are configured.

The configuration of the slip control unit 2 will be described below as an example. FIG. 4 is a flowchart showing the control operation of the slip control unit 2. Figure 4
At first, an ignition switch (not shown) is turned on to start activation of the controller of each control unit and the transmitting / receiving means. When a signal is received from another control unit after these start-ups, the controller of the slip control unit 2 determines whether the signal is the connection confirmation signal output from the engine control unit 1.

As a result, when it is determined that the received signal is the connection confirmation signal output from the engine control unit 1, the controller of the slip control unit 2
The fact that the connection confirmation signal has been received from the engine control unit 1 is stored and a connection response signal is output. When the signal is further received, the controller of the slip control unit 2 sends the signal to the engine control unit 1
It is determined whether or not it is a multiplex communication start signal including the connection information of each control unit output from.

As a result, if YES, the controller of the slip control unit 2 stores the connection state of each control unit and starts multiplex communication. On the other hand, when NO, the signal is recognized as a connection response signal output from a control unit other than the engine control unit 1,
The controller of the slip control unit 2 waits until a multiplex communication start signal including connection information of each control unit is input from the engine control unit 1, and at the time of receiving the multiplex communication start signal, confirms the connection state of each control unit. Store and start multiplex communication.

On the other hand, when it is determined that the received signal is not the connection confirmation signal output from the engine control unit 1 after the controller and the transmission / reception means are activated, the activation of the controller of the slip control unit 2 is delayed. As a result, the slip control unit 2 cannot receive the connection confirmation signal output from the engine control unit 1 and cannot output the frame-shaped connection response signal F4, the predetermined time t1 has passed, and the engine control has already been performed. A multiplex communication start signal is output from the unit 1, and multiplex communication is started between the engine control units 1, 4WS control unit 3 and the body system control unit 4, and the received signal is the engine control units 1, 4WS.
Since it is recognized that the control signal contains the control data output from the control unit 3 or the body system control unit 4 to the multiplex communication line 9, the control signal is used as a trigger signal for multiplexing with other control units. In order to start communication, the slip control unit 2 sends a connection notification signal notifying that the multiplex communication line 9 is connected.
Output to.

The other control units that have received this connection notification signal output to the multiplex communication line 9 a confirmation signal requesting confirmation that the slip control unit 2 is connected to the multiplex communication line 9. When the slip control unit 2 receives this confirmation signal from another control unit, it outputs a response signal, and then stores the connection state of each control unit when the signal is received from the other control unit. Then, multiplex communication is started.

According to this embodiment, the slip control unit 2 cannot receive the connection confirmation signal from the engine control unit 1 within a predetermined time t1 after the connection confirmation signal is output from the engine control unit 1, Even if the connection response signal cannot be output, as long as there is no abnormality in the connection response signal, the multiplex communication start signal is output from the engine control unit 1 and, after the multiplex communication is started, the control data is included from another control unit. When the control signal is received, the slip control unit 2 is configured so that the multiplex communication can be started with another control unit. The data can be provided, thus making it possible to improve the reliability of the control performed by each control unit.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the invention described in the claims, and those are also included in the scope of the present invention. Needless to say. For example, in the above-mentioned embodiment, due to the delay of the start of the controller,
Despite no abnormality, the slip control unit 2
However, after the connection confirmation signal is output from the engine control unit 1, the engine control unit 1
When the connection confirmation signal from the control unit could not be received and the connection response signal could not be output, after the multiplex communication was started with the other control unit, the multiplexing with the other control unit was started. Although only the case of participating in the communication is described, the 4WS control unit 3 or the body system control unit 4 causes
Despite no abnormality, within a predetermined time t1 after the connection confirmation signal is output from the engine control unit 1,
Even when the connection confirmation signal from the engine control unit 1 could not be received and the connection response signal could not be output, in the same manner as described above, after the multiplex communication was started, the other control unit Can participate in multiplex communication.

Further, although the engine control unit 1 outputs the connection confirmation signal in the above-mentioned embodiment, it may be made to output the connection confirmation signal to another control unit. In this case, the engine control unit 1 receives the connection confirmation signal within a predetermined time t1 after the connection confirmation signal is output from another control unit, although there is no abnormality due to the delay in the activation of the controller. I can't
Even when the connection response signal cannot be output, the engine control unit 1 can participate in the multiplex communication with other control units after the multiplex communication is started in the same manner. .

[0031]

According to the present invention, a plurality of control units each having a controller and a transmitting / receiving means are connected to a common multiplex communication line, and signals can be transmitted / received to / from each other via the multiplex communication line. Before a multi-communication state is established in which a plurality of control units transmit and receive each other, a predetermined control unit sends a connection confirmation signal for requesting a response as to whether or not the control unit is connected to the multi-communication line. To the control unit, and only the control unit that outputs a response signal to the predetermined control unit within a predetermined time in response to the connection confirmation signal is connected to a common multiplex communication line, and multiplex communication is performed. It is determined that it is possible that the control unit is connected to the common multiplex communication line after the elapse of the predetermined time after the connection confirmation signal is output. In the multiplex communication apparatus configured to output the signal start signal to the multiplex communication line to start the multiplex communication, the multiplex communication start signal is output within a predetermined time while the connection response signal cannot be output. In addition, the control unit that could not participate in the multiplex communication can also participate in the multiplex communication after the start of the multiplex communication, and the necessary and sufficient data for control is transmitted and received between the respective control units to perform the control. It is possible to provide a multiplex communication device capable of improving the reliability of.

[Brief description of 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 showing a configuration of a signal transmitted by each control unit.

FIG. 3 is a time chart showing signal output from each control unit.

FIG. 4 is a flowchart showing a control operation of a slip control unit.

[Explanation of symbols]

 1 engine control unit 2 slip control unit 3 4 WS control unit 4 body system control unit 5, 6, 7, 8 node 9 multiplex communication line

Claims (4)

[Claims] 1. A plurality of control units, each of which includes a controller and a transmitting / receiving means, are connected to a common multiplex communication line, and are configured to be capable of transmitting and receiving signals to and from each other via the multiplex communication line. Before reaching the multiplex communication state in which the units transmit and receive each other, a predetermined control unit outputs a connection confirmation signal for requesting a response as to whether or not it is connected to the multiplex communication line, to another control unit. It is determined that only the control unit that outputs a response signal to the predetermined control unit within a predetermined time in response to the connection confirmation signal is connected to a common multiplex communication line, and multiplex communication is possible. Then, after outputting the connection confirmation signal, which control unit is
In the multiplex communication device configured to output a multiplex communication start signal including information on whether or not it is connected to a common multiplex communication line to the multiplex communication line, within the predetermined time, A configuration in which a control unit that cannot output a connection response signal participates in multiplex communication when a control signal is received from another control unit after the predetermined control unit outputs a multiplex communication start signal A multiplex communication device characterized by the above. 2. The control unit that cannot output a connection response signal within the predetermined time, the predetermined control unit outputs the multiplex communication start signal, and then the control signal from the predetermined control unit. 2. It is configured to participate in multiplex communication after receiving the message.
The multiplex communication device as set forth in. 3. The control unit that was unable to output a connection response signal within the predetermined time period, after the predetermined control unit outputs the multiplex communication start signal, outputs a control signal from another control unit. After receiving, output a connection notification signal to the multiplex communication line, from another control unit,
3. The multiplex communication device according to claim 1, wherein the multiplex communication device is configured to participate in multiplex communication when a response signal is input to the connection notification signal. 4. A control signal from the predetermined control unit after the control unit that was unable to output the connection response signal within the predetermined time, after the predetermined control unit outputs the multiplex communication start signal. After receiving the connection notification signal, the connection notification signal is output, and when a response signal is input to the connection notification signal from another control unit, the connection notification signal is added to the multiplex communication. 4. The multiplex communication device according to any one of items 1 to 3.