JPH089471A - Mobile communication system - Google Patents

Abstract

PURPOSE:To suitably interrupt and recover communication when any abnormality is generated in communication due to any temporary noise or the like. CONSTITUTION:Various kinds of ECU 1 to 4 are connected by a common communication line 5. For example, the ECU 1 for engine is provided with a CPU 6 for calculating operating state data or various control data and a communication control circuit 10 for controlling communication to the communication line 5. The communication control circuit 10 is provided with a control logic part 15, driver 16, receiver 17 and opening/closing circuit 18. When any abnormality is generated in communication, the control logic part 15 interrupts communication by 'opening' the opening/closing circuit 18. On the other hand, the CPU 6 sets the recovery time of communication corresponding to the number of times of interruption of communication, 'closes' the opening/closing circuit 18 at that recovery time and recovers the communication from the interrupted state. When the number of times of interruption reaches the specified number of times, the recovery operation with the interruption is stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle communication system, and more particularly to a vehicle communication system in which a plurality of vehicle-mounted control devices having a communication control function are connected by a common communication line.

[0002]

2. Description of the Related Art In a vehicle communication system of this type, a plurality of vehicle-mounted control devices having a communication control function are connected by a common communication line, and data communication such as various calculation data is actively carried out through this communication line. Done. Then, when an abnormality occurs in the communication line or the like, the communication is interrupted for a predetermined time and then restored. In addition, since the restoration process when an abnormality occurs requires a large calculation load such as initialization process,
When the number of times communication is interrupted due to a communication error reaches a predetermined number of times during one run, the subsequent recovery operation of communication is stopped. And after the communication is stopped,
Control is performed by a certain value instead of the data received by communication.

[0003]

However, in a vehicle communication system, for example, when a strong electromagnetic wave from a power transmission line or a broadcasting station is received while a vehicle is traveling, a communication abnormality occurs due to noise. In a communication system in which communication is interrupted for a predetermined number of times, the number of times of interruption immediately reaches the specified number even if there is a temporary electromagnetic interference. In other words, even if the vehicle is separated from the electromagnetic wave area and the communication abnormality (electromagnetic noise) is eliminated, the communication cannot be restored.

Further, even if the communication line is sandwiched between doors or the like and temporarily short-circuited, the number of interruptions immediately reaches the specified number, so that communication is not restored even though the short-circuit is eliminated. become.

The present invention has been made in view of the above problems, and an object thereof is to appropriately perform interruption and restoration of communication when communication abnormality occurs due to temporary noise or the like. An object of the present invention is to provide a vehicle communication system.

[0006]

In order to achieve the above object, the invention according to claim 1 is characterized in that a plurality of vehicle-mounted control devices having a communication control function are connected by a common communication line, and a communication abnormality occurs. In a communication system in which communication is temporarily interrupted and then restored, and the restoration operation is stopped when the number of communication interruptions reaches a prescribed number of times, from the interruption to the restoration depending on the number of communication interruptions. The gist is to have a means to change the time required for.

According to the second aspect of the present invention, the longer the communication is interrupted, the longer the time required for the recovery from the interruption. According to a third aspect of the present invention, a plurality of vehicle-mounted control devices having a communication control function are connected by a common communication line, and when a communication abnormality occurs, the communication is temporarily interrupted and then restored, and In a communication system in which the restoration operation is stopped when a predetermined number of times is reached, a means for changing the time required for the restoration from the interruption according to the time from the restoration of communication to the next interruption is provided. Is the gist.

According to the fourth aspect of the invention, the longer the time from the restoration of communication to the next interruption, the longer the time required from the interruption to the restoration.

[0009]

According to the first aspect of the invention, when the communication is abnormal, the communication is temporarily interrupted and then restored, and when the number of interrupted communications reaches a predetermined number of times, the return operation is stopped. At this time, the time required from interruption to restoration is changed according to the number of times of interruption of communication. In other words, even when communication is interrupted and restored due to a temporary communication error such as electromagnetic interference, the time until the number of interruptions reaches the specified number is properly adjusted, and careless communication is required as in the past. It is possible to suppress the inability to return.

According to the second aspect of the invention, the larger the number of interruptions of communication, the longer the time from the interruption to the restoration. According to the third aspect of the invention, when the communication is abnormal, the communication is temporarily interrupted and then restored, and when the number of interrupted communications reaches a predetermined prescribed number, the return operation is stopped. At this time, the time required from the interruption to the restoration is changed according to the time from the restoration of the communication to the next interruption. That is, similar to the operation of claim 1, electromagnetic interference,
Even when communication is interrupted and restored due to a temporary communication error, the time until the number of interruptions reaches the specified number is properly adjusted, and it is impossible to unintentionally restore communication as in the past. Suppressed.

According to the invention described in claim 4, the longer the time from the restoration of communication to the next interruption, the longer the duration from the interruption to the restoration.

[0012]

【Example】

(First Embodiment) A first embodiment of the vehicle communication system of the present invention will be described below with reference to the drawings.

FIG. 1 shows an outline of a vehicle communication system in this embodiment. As shown in the figure, a vehicle (automobile) is equipped with a plurality of vehicle-mounted control devices for performing electronic vehicle control. Specifically, electronic control unit for engine (ECU for engine) 1, electronic control unit for automatic transmission (ECU for AT) 2, electronic control unit for meter (ECU for meter) 3, electronic control for antilock brake system A device (ABS ECU) 4 is mounted. Each ECU
1 to 4 are connected by a common communication line 5, and the communication line 5
It is possible to communicate with each other via.

Here, the configuration of the ECUs 1 to 4 will be described in detail by taking the engine ECU 1 as an example. In the engine ECU 1, the CPU 6, which is a one-chip microcomputer, the input interface 7, and the output interface 8 are connected by a bus 9. C
The PU 6 is provided with a memory 6a that stores a control program and temporarily stores calculation data.
The input interface 7 is connected to a sensor group 12 including an accelerator pedal position sensor and an engine rotation angle sensor, and a switch group 13 including a starter switch. Further, the output interface 8 is connected to an actuator group 14 including a DC motor for controlling the throttle opening position.

Then, the CPU 6 calculates various calculation data (engine speed data, accelerator pedal position data, etc.) based on the detection signals from the sensor group 12 and the switch group 13, and optimally controls the state of the engine. Actuator group (DC motor for throttle drive)
Control 14.

The communication control circuit 10 that controls the communication line 5 includes a control logic unit 15, a receiver 16, a driver 17, and an opening / closing circuit 18. The control logic unit 15 uses the transmission data transferred from the CPU 6 and other ECs.
Received data received from U is accumulated, and the communication line 5 is monitored. The control logic unit 15 and the CPU 6 are connected by a data transfer line 11, and transmission data is transferred from the CPU 6 to the control logic unit 15 via the data transfer line 11 and the control logic unit 1
The received data is transferred from 5 to the CPU 6.

Further, the receiver 16 receives a signal from the communication line 5, and the driver 17 transmits a signal to the communication line 5. The open / close circuit 18 includes the control logic unit 15 or the CPU 6.
The communication path between the control logic unit 15 and the communication line 5 is switched to "open" or "closed" in accordance with a command from the. That is, when a communication abnormality occurs, the control logic unit 1
The open / close circuit 18 is opened in response to a command from 5, and communication is interrupted. After the communication is interrupted for a predetermined time, the switching circuit 18 is closed by the command from the CPU 6 and the communication is restored.

The other ECUs 2 to 4 also have substantially the same configuration as the engine ECU 1, each of which is provided with a CPU, a communication control circuit, etc., and is based on a detection signal from a sensor group or a switch group. Control various actuator groups. Then, each of the ECUs 1 to 4 exchanges data necessary for calculating various control amounts with each other. For example,
The engine speed data calculated by the engine ECU 1 is transmitted to the meter ECU 3 via the communication line 5 and used by the meter ECU 3 to drive the tachometer. Further, the vehicle speed data from the AT ECU 2 is transmitted to the engine ECU 1 through the communication line 5, and the engine ECU 1
Used for throttle control.

On the other hand, FIG. 2 shows a format of a communication frame transmitted through the communication line 5. In this communication system, a frame configured as shown in the figure is transferred between the ECUs 1 to 4. In the same frame, "SOF
"(Start of frame)" is a portion indicating the beginning of the frame, and "Data" following it is a portion indicating a data field in which the content of the transmission data is incorporated. Further, "CRC" is a portion for performing error detection in data transmission and data recording using a CRC (cyclic redundancy check) method, and "EOF (end of frame)" is a portion for indicating the end of the frame.

The operation of the vehicle communication system configured as described above will be described below with reference to FIGS. FIG. 3 is a flowchart showing a processing routine for interrupting communication by detecting an abnormality in the communication state (transmission data error), and this routine is executed by the control logic unit 15 in the communication control circuit 10. FIG. 4 is a flowchart showing a processing routine for setting the time required from the interruption of communication to the restoration (referred to as restoration time TF), which is executed by the CPU 6.

Now, when the routine of FIG. 3 is activated, the control logic unit 15 determines in step 100 whether or not there was a communication return instruction immediately before. This return command is issued when the communication returns from the interrupted state, and when step 100 is affirmed, the control logic unit 15
Shifts to step 190 to clear the error counter Cerr to "0", and when negative determination is made in step 100, shifts to step 110. Here, the error counter Cerr is a counter indicating an abnormal state of transmission data.

Further, the control logic unit 15 executes the step 1
The communication state of the transmission data is determined at 10 to 160, and the error counter Cerr is counted up or down according to the determination result. Specifically, the control logic unit 15 determines whether or not the transmission bit at the time of transmission and the received bit do not match in step 110, and if they do not match, the process proceeds to step 120. In this case, the control logic unit 15 determines the error counter C in step 120.
After counting up err by “8”, the process proceeds to step 170. In addition, the control logic unit 15 executes step 13
When the CRC error is 0, the CRC error of the received frame is discriminated. In this case, the control logic unit 15 determines the error counter C in step 140.
After counting up err by “4”, the process proceeds to step 170. The error determination in steps 110 and 130 is not limited to the above method.

Further, the control logic unit 15 determines in step 150 whether the frame data is normal,
If it is normal, the process proceeds to step 160. In this case, the control logic unit 15 counts down the error counter Cerr by “16” in step 160, and then executes step 17
Move to 0. In addition, steps 110, 130, 150
If both are negative, the error counter Cerr
Step 17 without counting up or down
Move to 0. This corresponds to the case where the communication path between the control logic unit 15 and the communication line 5 is disconnected and the communication is interrupted.

Thereafter, the control logic unit 15 executes step 1
At 70, it is determined whether the error counter Cerr is "256" or more. Then, if Cerr <256,
The control logic unit 15 directly returns to step 100, and if Cerr ≧ 256, the open / close circuit 18 is opened in step 180 to interrupt communication, and then the process returns to step 100.

In the process of FIG. 3, the error counter Cerr is counted up or down by weighting it for each error condition. As a result, with respect to a communication error caused by randomly generated noise for a short time, interruption of communication in that case is prevented.

On the other hand, in the routine of FIG. 4, the CPU 6
Determines in step 200 whether or not a communication recovery operation is necessary, and if not, terminates this routine as it is. At this time, if the restoration process (the processes of subsequent steps 210 to 240) accompanying the previous communication interruption has already been performed, the affirmative determination is made in step 200. If the returning operation is necessary, the CPU 6 increments the interruption number counter CF by "1" in step 210. here,
The interruption counter CF counts the number of interruptions of communication during one traveling of the vehicle, and is initialized (CF = 0) when the IGSW is turned on.

Thereafter, in step 220, the CPU 6 sets the interruption counter CF to a predetermined prescribed number (in the present embodiment,
16 times) is determined. And CF
If ≤16, the CPU 6 calculates the recovery time TF according to the interruption number counter CF in step 230 (TF =
CF 16). Here, the restoration time TF is weighted by 16 ms with respect to the value of the interruption counter CF.
Further, the CPU 6 sets the return time TF obtained as described above in the register in the following step 240. afterwards,
The CPU 6 closes the open / close circuit 18 at the timing when the recovery time TF set in the register elapses.

If CF> 16 in step 220, the CPU 6 ends this routine. That is,
When CF> 16, steps 230 and 240 are not executed, so that the switching circuit 18 is held in the "open" state, and thereafter the communication recovery operation is stopped.

FIG. 5 is a timing chart showing the interruption and restoration operations of communication due to noise. FIG. 5 (a) shows the operation of the communication system of this embodiment and FIG. 5 (b) shows the conventional communication system. Shows the operation of. Time t1 to t in FIG.
Reference numeral 2 indicates a noise generation period. In FIG. 5, the operation of the switching circuit 18 from “closed” to “open” indicates interruption of communication, and the operation of “open” to “closed” indicates restoration of communication.

First, this embodiment will be described with reference to FIG. When noise occurs at time t1, the error counter Cerr is counted up, and at the timing when Cerr ≧ 256, the open / close circuit 18 is opened and communication is interrupted. At this time, the interruption counter CF is "0".
Is changed from "1" to "1", and the recovery time TF1 (= 16 ms) is set. The recovery time TF in FIG. 5 is provided with a subscript corresponding to the interruption number counter CF.

Then, after the recovery time TF1 has elapsed, the switching circuit 18 is "closed" and communication is restored. However, since noise is generated even when this communication is restored, Cer
At the timing of r ≧ 256, the switching circuit 18 becomes “open” and the communication is interrupted. At this time, the interruption counter CF is changed from "1" to "2", and the recovery time TF2 is changed.
(= 32 ms) is set.

After that, since noise is continuously generated, communication interruption and restoration operations are repeatedly performed until time t2 is reached. That is, the interruption time counter CF is changed from "2" to "3", and the recovery time TF3 (= 48).
ms) is set, and the interruption counter CF
Change from "3" to "4" and return time TF4 (= 6
4 ms) is set.

On the other hand, in the conventional example of FIG. 5B, time t1
5A, the communication is interrupted, the interruption frequency counter CF is changed from "0" to "1", and the recovery time TF1 '(= 16 ms) is set. Then, the communication is restored after the lapse of the restoration time TF1 '. After that, until the time t2 is reached, a restoration time TF2 'to TF7' of a fixed time (16 ms) is set for each interruption of communication, and the interruption and restoration operations are repeatedly performed. In this case, the return time TF1 'to TF7' are all the same time (16m
s) is set. Therefore, at times t1 to t2, the interruption number counter CF is counted up to "4" in FIG. 5A, whereas the interruption number counter CF is counted up to "7" in FIG. 5B.

If the noise is continuously generated after the time t2, the interruption number counter CF reaches the specified number (16 times) in 256 ms in the conventional example, whereas it is 2176 ms in the shortest in this embodiment. And the interruption counter C
F will reach the specified number of times (16 times).

According to the vehicle communication system of this embodiment described in detail above, the following effects can be exhibited. That is, even when noise is superimposed on the communication line 5 due to electromagnetic interference or when the communication line 5 is shorted by being sandwiched between doors, the number of interruptions is reduced even when the communication is interrupted and restored due to a temporary communication error. The time to reach the specified number of times is properly adjusted. Therefore, it is possible to prevent the communication from being unintentionally unable to be restored as in the conventional case. Further, since it takes a long time for the number of interruptions to reach the specified number, it is possible to properly deal with long-term noise and the like. Furthermore, since the number of restoration processes that generate an interrupt when noise occurs is reduced, the software processing load on the CPU 6 is reduced, and the influence on vehicle control can be reduced. (Second Embodiment) Next, a second embodiment of the present invention will be described focusing on the differences from the first embodiment. In the first embodiment, the recovery time TF is changed in direct proportion to the value of the interruption frequency counter CF. On the other hand, in the second embodiment,
It is changed according to the state of the communication line 5 (the time required from the restoration to the next interruption).

FIG. 6 shows a routine for setting the recovery time TF in the second embodiment, and this routine corresponds to the routine in FIG. 4 of the first embodiment. Note that steps 300 to 320 in FIG. 6 are the same processes as steps 200 to 220 in FIG. 4, and here, CF ≦≦ in step 320.
Steps 330 to 350 following the determination process of 16 will be described.

That is, the CPU 6 measures the required time TS from the restoration of communication to the next interruption in step 330, and calculates the restoration time TF reflecting the required time TS in the following step 340 (TF = TS 16). Here, the required time TS from the restoration of communication to the next interruption
Corresponds to the time until the error counter Cerr shown in the routine of FIG. 3 reaches a predetermined value (Cerr ≧ 256). Therefore, by lengthening the recovery time TF according to the required time TS, the count of the interruption counter CF becomes faster when the state of communication abnormality does not change due to disconnection or the like.
When the communication error state changes intermittently, the count of the interruption frequency counter CF is delayed. Further, the CPU 6
In the following step 350, the return time TF is set in the register. When the recovery time TF set in the register has elapsed, the CPU 6 closes the open / close circuit 18 to restore communication.

In the second embodiment, the restoration time TF can be set according to the state of communication abnormality, and the restoration processing of communication can be properly performed. In this way, the object of the present invention can be achieved as in the case of the first embodiment described above.

The present invention can be embodied in the following modes other than the above embodiment. In the first embodiment, the return time TF is set in proportion to the value of the interruption counter CF, and in the second embodiment, the required time TS from the return to the interruption is set.
Although the recovery time TF is set in proportion to, it may be changed. For example, the interruption counter CF and the required time T
It is also possible to newly set the amount of change in the recovery time TF with respect to S. The recovery time TF may be set by combining the above two conditions (the value of the interruption counter CF and the required time TS).

[0040]

According to the invention described in claims 1 to 4, the excellent effect that the communication can be properly interrupted and restored when the communication is abnormal due to a temporary noise or the like is exhibited.

[Brief description of drawings]

FIG. 1 is a configuration diagram illustrating a vehicle communication system according to an embodiment.

FIG. 2 is a configuration diagram showing a format of a communication frame.

FIG. 3 is a flowchart showing a communication interruption processing routine executed by a control logic unit in the first embodiment.

FIG. 4 is a flowchart showing a communication recovery time setting routine executed by a CPU in the first embodiment.

5A and 5B are timing charts for explaining the operation in the first embodiment, FIG. 5A shows the operation of the communication system of the present embodiment, and FIG. 5B shows the operation of the conventional communication system. .

FIG. 6 is a flowchart showing a communication recovery time setting routine executed by a CPU in the second embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine ECU as an in-vehicle control device, 2 ... AT ECU as an in-vehicle control device, 3 ... Meter ECU as an in-vehicle control device, 4 ... ABS as an in-vehicle control device
ECU, 5 ... communication line, 6 ... CPU.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B60R 16/02 K H04L 12/40 29/14 H04Q 9/02 B

Claims (4)

[Claims] 1. A plurality of vehicle-mounted control devices having a communication control function are connected by a common communication line, and when a communication abnormality occurs, the communication is temporarily interrupted and then restored, and the communication interrupt frequency is a prescribed number of times. In the communication system in which the return operation is stopped when the time reaches, the vehicle communication system is provided with means for changing the time required from the interruption to the restoration according to the number of interruptions of the communication. 2. The vehicle communication system according to claim 1, wherein the time required for the recovery from the interruption is extended as the number of interruptions of the communication increases. 3. A plurality of vehicle-mounted control devices having a communication control function are connected by a common communication line, and when a communication error occurs, the communication is temporarily interrupted and then restored, and the communication interrupt frequency is a prescribed number of times. In the communication system in which the restoration operation is stopped when the number of times reaches, the means for changing the time required from the interruption to the restoration according to the time from the restoration of the communication to the next interruption is provided. Vehicle communication system. 4. The vehicle communication system according to claim 3, wherein the longer the time from the restoration of communication to the next interruption, the longer the time required from the interruption to the restoration.