JP3063017B2 - Multiplex transmission equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a so-called CSMA / CD (Carr
The present invention relates to a multiplex transmission apparatus in a multiplex transmission system using an ier Sense Multiple Access / Collision Detection transmission system.

[0002]

2. Description of the Related Art Conventionally, there has been a vehicle using a multiplex transmission system for transmitting various data in an automobile. The data in the automobile includes, for example, wheel speed data, and a wheel speed sensor for anti-lock brake is provided for each wheel to detect the rotation speed of the four wheels. The anti-lock brake control computer calculates the sensor values output from the four sensors, detects the lock state of the wheels at that time, and controls the brake pressure according to the state. When multiplex transmission is applied to such a system, four wheel speed sensors are arranged in independent multiplex nodes, and the four wheel speed information constitutes separate frames, respectively, Are transmitted to the antilock brake control computer, which is a multi-node. When a contention method such as the CSMA / CD method is adopted as this transmission method, the arrival times of the four wheel speed information frames may vary greatly because the delay time varies depending on the traffic.

In this case, since the antilock brake control computer cannot determine whether all the sensor values of the four wheels have been updated to the new sampling values,
The sensor value of the new sampling cycle and the sensor value of the previous sampling cycle are mixed and calculated.

[0004]

However, in the above-described transmission method, a situation occurs in which a sensor value of a new sampling cycle and a sensor value of a previous sampling cycle are mixed and calculated, so that appropriate brake pressure control is performed. There is a problem that it may not be possible. In addition, the above CSMA / CD
In addition to the transmission method, for example, using a time slot method,
Although a transmission method of collecting data from a plurality of nodes in one frame is also conceivable, in this method, it is necessary to generate a synchronization signal such as a periodic pulse indicating a data break from one specific node. Type. In the centralized control type transmission system, a signal that requires synchronization can be concentrated in a network that controls a single function. However, in general, a signal processed by a multiplex transmission system of an automobile is a single signal. It is not a function, and the engine, transmission,
Since it is used for control of multiple functions such as suspension and steering, a transmission system of distributed control has been desired.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a multiplex transmission apparatus capable of virtually simultaneously processing signals transmitted asynchronously on a multiplex transmission path, thereby appropriately processing a controlled object. The purpose is to provide.

[0006]

In order to achieve the above object, according to the present invention, there are provided a plurality of multiplex nodes connected to each other via a common multiplex transmission line, and each multiplex node comprises each data. In a multiplex transmission apparatus using a multiplex transmission method for communicating a frame, the multiplex node includes communication control means for performing communication of the frame in an independent distributed format, first storage means for storing an identifier for identifying data in the frame, A second storage unit that stores the identifier stored in the first storage unit in association with at least one group; and when a frame including data having the identifier is received, predetermined data is set in accordance with the identifier. A third memory for resetting the predetermined data when the data is read; and a third memory for receiving a frame having the identifier. A case in which all of the predetermined data is set in the fourth storage means for storing the data content of the frame corresponding to the identifier and the third storage means in the group associated with the second storage means In
A multiplex transmission device is provided that includes a notifying unit that notifies the outside that the data is set, and a transfer unit that transfers the contents of the data stored in the fourth storage unit to the outside.

[0007]

When all the data corresponding to the group associated with each identifier is set in the third storage means, the contents of the data stored in the fourth storage means corresponding to the identifier are stored in the external storage. Transfer to Therefore, signals transmitted asynchronously on the multiplex transmission path can be processed virtually simultaneously.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a configuration diagram showing a network configuration of a multiplex transmission system for a vehicle used for implementing the present invention. In the figure, the network includes an engine computer 11 for controlling the fuel injection amount and the ignition timing, an antilock traction computer 12 for controlling the driving force and brake of the vehicle, a transmission computer 13 for controlling the transmission, and four wheel speed sensors. 14-1
Each node 7 is connected by a multiplex transmission line (multiplex bus) 10 to transmit and receive signals serially by a non-destructive arbitration type CSMA / CD access method.

FIG. 2 shows the engine computer 11,
FIG. 3 is a diagram showing a message format normally transmitted and received between nodes of an antilock traction computer 12 and a transmission computer 13. In the figure, the message is a start code (SOM) indicating the beginning of the message, and a plurality of nodes
When a signal is transmitted to 0, a priority (PRI) for determining the priority order, a message ID indicating the content of the succeeding data, a control data area (CONT) including data indicating the data length, and a control data area (CONT) described above. Data area (variable length), error check code such as CRC, EOD indicating end of data, ACK area for returning acknowledgment signal (ACK) from all nodes in bit correspondence, and end of message. EOM showing
The data is composed of frames.

The engine computer 11, the anti-lock traction computer 12, and the transmission computer 13 operate independently of each other, and can communicate with each other at an arbitrary timing. The signal is transmitted to the multiplex bus 10 at an arbitrary timing. When a message collision occurs on the multiplex bus 10 stochastically, priority control is performed without destroying the message, and a message having a low priority is automatically transmitted by comparing PRI data. The transmission is interrupted, and the transmission of the message with the higher priority is continued.

The nodes of the four wheel speed sensors 14 to 17 have a function of transmitting wheel speed signals to the antilock traction computer 12, respectively. When receiving the wheel speed sensor signals from the four wheel speed sensors 14 to 17 nodes, the anti-lock traction computer 12 virtually receives the four sensor signals at the same time and processes them simultaneously. The configuration will be described with reference to FIG.

In FIG. 3, a multiplex node of the antilock traction computer 12 includes a communication control circuit 20 for transmitting / receiving a frame to / from the multiplex bus 10 and a memory unit 21 for storing predetermined data in the received frame.
And a NAND circuit 22 for notifying that all frames of a predetermined group have been received, and fetching data stored in the memory unit 21 in response to the notification, and controlling the inside of the vehicle based on the data. Control circuit (CPU) 2
And 3.

The communication control circuit 20 receives each frame of the four sensor signals according to the present invention via the multiplex bus 10. The memory unit 21 has a first storage area 21a that stores an identifier of data allocated to each frame of the received sensor signal, and a second storage area 21a that stores data for associating the received identifier with a preset group. When receiving the storage area 21b and the frame having the identifier, the reception flag is set to the third storage area 21b.
And a fourth storage area 21d for storing the data content of the frame having the identifier.

The NAND circuit 22 is provided for each group, and notifies the CPU 23 when all frames of the corresponding group are received.

[0015]

[Outside 1]

Data contents are taken in, and the driving force and brake of the vehicle are controlled based on the data. Next, the operation of the multiple nodes of the antilock traction computer 12 according to the present invention will be described with reference to FIG. In addition,
The identifiers of the data of the four wheel speed signals stored in the first storage area 21a, for example, the identifier of the data from the front wheel right (FR) wheel speed sensor 14 is 55H, and the identifier of the data is 55H from the front wheel left (FL) wheel speed sensor 15. The identifier of the above data is 56H, the identifier of the above data from the rear wheel right (RR) wheel speed sensor 16 is 57H, and the rear wheel left (RL) wheel speed sensor 1 is
It is assumed that the identifier of the data from No. 7 is 58H, and the group identified by the identifiers 55H to 58H is stored as one group in the second storage area 21b.

In this state, the nodes of the wheel speed sensors 14 to 17 sample the sensor values at a specific sampling cycle based on the current wheel speed data, and send the sensor values to the multiplex bus 10 as a multiplex signal. I do. Here, for example, as shown in FIG.
7 is a multiplexed bus using the wheel speed signal as a multiplexed signal.
When the signal is sent out to 0, the communication control circuit 20 of the antilock traction computer 12 receives the signal.
Since the identifier in the frame is 58H,
The memory unit 21 compares whether or not any of the identifiers stored in the first storage area 21a matches the identifier of the frame.

If the two identifiers match, the memory unit 21 sets a reception flag "1" in the third storage area 21c corresponding to the identifier 58H (see FIG. 4B). And the data of the received frame is stored in the fourth storage area 21d corresponding to the identifier 58H. If the two identifiers do not match, the data is ignored without being stored.

Next, when the communication control circuit 20 receives the multiplexed signal transmitted from the node of the FR wheel speed sensor 14 onto the multiplexed bus 10 (see FIG. 4A), the memory unit 21 stores the multiplexed signal in the same manner as described above. The identifier stored in the first storage area 21a is compared with the identifier in the frame of the signal. Here, since the identifier in the frame is 55H,
The memory unit 21 sets the reception flag “1” in the third storage area 21c corresponding to the identifier 55H (FIG. 4B).
And the data of the received frame is stored in the fourth storage area 21d corresponding to the identifier 55H.

Next, when the communication control circuit 20 receives a multiplex signal transmitted from the node of the FL wheel speed sensor 15 onto the multiplex bus 10 (see FIG. 4A), the memory unit 21 stores the multiplex signal in the same manner as described above. The identifier stored in the first storage area 21a is compared with the identifier in the frame of the signal. Here, since the identifier in the frame is 56H,
The memory unit 21 sets the reception flag “1” in the third storage area 21c corresponding to the identifier 56H (FIG. 4B).
And the data of the received frame is stored in the fourth storage area 21d corresponding to the identifier 55H.

Further, when the communication control circuit 20 receives a multiplex signal transmitted from the node of the RR wheel speed sensor 16 onto the multiplex bus 10 (see FIG. 4A), the memory unit 21
As described above, the identifier stored in the first storage area 21a is compared with the identifier in the frame of the signal. Here, since the identifier in the frame is 57H, the memory unit 21 stores the third identifier corresponding to the identifier 57H.
The reception flag "1" is set in the storage area 21c of FIG.
(See (b)), and stores the data of the received frame in the fourth storage area 21d corresponding to the identifier 55H.

As a result, according to the data in the second storage area 21b, the identifier 55 defined as one group
Since the third storage areas 21c corresponding to H to 58H are all set to "1" (see FIG. 4 (b)), the NAND circuit 22 operates as shown in FIG. 4 (c).

[0023]

[Outside 2]

The reception flag in the storage area 21c is reset.

[0025]

[Outside 3]

The memory section 21 is read out and controlled, and the fourth
The data of the four wheel speeds stored in the storage area 21d are transferred and captured. Then, the CPU 23 performs antilock traction control based on the acquired four wheel speed data. Therefore, in this embodiment, the data of the signal asynchronously communicated on the multiplex bus is once stored in the memory, and when all the data necessary for the predetermined control is stored, the data is transmitted to the control circuit. Therefore, the data can be processed virtually simultaneously.

In this embodiment, specific data is stored in the second storage area to group a specific identifier. However, the present invention is not limited to this.
It is also possible to realize data grouping by storing identifiers to be grouped in a predetermined storage area without providing the storage area described above. Further, in the present invention, when any of the nodes that transmit the frames of the grouped identifiers fails, for example, when the node of the FL wheel speed sensor in the above embodiment fails, the frame of the identifier 58H is permanently stored in the FL. Since the information is not transmitted from the node of the wheel speed sensor, in the node of the antilock traction computer, all the third storage areas do not become "1", and there is a disadvantage that the data of the wheel speed cannot be received. In this case, for example, by providing a timer for all of the four identifiers, that is, for each group, the above inconvenience can be solved. That is, in this embodiment, the timer is reset when all the third storage areas corresponding to one group change from "1" to "0", and are reset for a specific time, for example, the maximum sampling of the wheel speed sensor. If the node of the FL wheel speed sensor fails, the frame of the identifier 58H is not received.
The count of the timer expires before all the storage areas of "1" become "1", and the CPU is informed of the expiration. Thus, the CPU can detect that some abnormality has occurred, and for example, performs the degeneration control based on the wheel speed data of three wheels excluding 58H from the group defined by the identifier stored in the second storage area. Or an appropriate action such as stopping all control of the antilock traction computer can be taken.

In the other embodiments, a timer is provided for each group. However, the present invention is not limited to this. For example, a timer may be provided for each received identifier and a specific time is counted to detect the occurrence of abnormality. It is also possible.

[0029]

As described above, according to the present invention, there are provided a plurality of multiplex nodes mutually connected via a common multiplex transmission line, and a multiplex for communicating a frame composed of data among the multiplex nodes. In a multiplex transmission apparatus using a transmission method, the multiplex node includes communication control means for communicating a frame in an independent distributed format, first storage means for storing an identifier for identifying data in the frame, and the first storage means. Second storage means for storing the identifier stored in the means in association with at least one group, and upon receiving a frame composed of data having the identifier, predetermined data is set corresponding to the identifier, and the data is A third storage unit that, when read, resets the predetermined data; and, when a frame having the identifier is received, a frame corresponding to the identifier is received. A fourth storage unit that stores the data content of the frame; and a case where all of the predetermined data is set in the third storage unit in the group associated with the second storage unit, And a transfer means for transferring the contents of the data stored in the fourth storage means to the outside, so that a signal transmitted asynchronously on the multiplex transmission path is provided. Can be virtually simultaneously processed, whereby the controlled object can be appropriately processed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a network configuration of a multiplex transmission system for a vehicle used for carrying out the present invention.

FIG. 2 is a diagram showing a message format transmitted and received on a network.

FIG. 3 is a block diagram showing a configuration of the antilock traction computer shown in FIG.

FIG. 4 is a diagram for explaining the operation of the antilock traction computer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Multiple transmission path (multiple bus) 11 Engine computer 12 Antilock traction computer 13 Transmission computer 14-17 Wheel speed sensor 20 Communication control circuit 21 Memory unit 21a First storage area 21b Second storage area 21c Third storage Area 21d Fourth storage area 22 NAND circuit 23 Control circuit (CPU)

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshikazu Shinnoichi 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (72) Seiji Hirano 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Inside Mazda Co., Ltd. (72) Inventor Hiroaki Sakamoto 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Co., Ltd. (56) References JP-A-3-293836 (JP, A) JP-A-5-175974 (JP, A) JP-A-5-207557 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 12/28

Claims (3)

(57) [Claims] 1. A multiplex transmission apparatus in a multiplex transmission system having a plurality of multiplex nodes mutually connected via a common multiplex transmission path, and communicating a frame composed of data between the multiplex nodes. The node includes communication control means for communicating a frame in an independent distributed format, first storage means for storing an identifier for identifying data in the frame, and at least one identifier stored in the first storage means. When receiving a frame including data having the identifier and second storage means for storing the data in association with the group, predetermined data is set corresponding to the identifier, and when the data is read, the predetermined data is reset. Receiving the frame having the identifier, and storing the data content of the frame corresponding to the identifier. When all the predetermined data is set in the fourth storage unit and the third storage unit in the group associated with the second storage unit,
A multiplex transmission apparatus comprising: a notifying unit for notifying that the data is set to the outside; and a transfer unit for transferring the contents of the data stored in the fourth storage unit to the outside. 2. The informing means includes, for each group, counting means for counting whether all the third storage means in the associated group have been set within a predetermined time, and counting by at least one of the counting means. 2. The multiplex transmission apparatus according to claim 1, wherein when the predetermined time has expired, the fact that the predetermined time has expired is notified to the outside. 3. The notifying unit has, for each identifier, a counting unit that counts whether a frame having the identifier is received within a predetermined time, and when the count of at least one of the counting units has expired the predetermined time. 2. The multiplex transmission apparatus according to claim 1, wherein the completion is notified to the outside.