WO2019225500A1

WO2019225500A1 - Communication system, connecting device, control device, communication line cutoff method, and computer program

Info

Publication number: WO2019225500A1
Application number: PCT/JP2019/019693
Authority: WO
Inventors: 佑樹佐野; 勝也生田; 剛史紺谷
Original assignee: 株式会社オートネットワーク技術研究所; 住友電装株式会社; 住友電気工業株式会社
Priority date: 2018-05-22
Filing date: 2019-05-17
Publication date: 2019-11-28
Also published as: JP2019205038A

Abstract

Provided are a communication system, a connecting device, a control device, a communication line cutoff method, and a computer program for detecting a fault such as short-circuiting, a ground fault, etc., in bus-type communication lines and cutting off a fault location. A communication system according to the present embodiment is a bus-type communication system in which a communication device is connected to each of a plurality of communication branch lines branching off from a communication trunk line, and in which a plurality of the communication devices perform communication via the communication trunk line and the communication branch lines, wherein the communication system is provided with: a current detection unit for detecting a current flowing in each of the communication branch lines; a switch provided to each of the communication branch lines, the switch switching between conduction and cutoff of the communication line; and a control unit for performing a control to shut off the switch on the basis of the detection result of the current detection unit. The control unit preferably shuts off the switch provided to a communication branch line in which a current exceeding a threshold value is detected by the current detection unit.

Description

Communication system, connection device, control device, communication line blocking method, and computer program

The present disclosure relates to a communication system that performs communication via a bus-type communication line, and a connection device, a control device, a communication line blocking method, and a computer program used in this system.

In recent years, in-vehicle devices such as a plurality of ECUs (Electronic Control Units) are mounted on vehicles. The plurality of in-vehicle devices are connected via a communication line, and perform cooperative operation by exchanging information through communication. For example, CAN (Controller 規格 Area 通信 Network) communication standards are widely used for in-vehicle communication. In the CAN communication standard, a plurality of in-vehicle devices are connected via a bus-type communication line.

In Patent Document 1, it is determined whether or not communication is possible on a route formed by appropriately switching a combination of connection / separation of a plurality of switches provided in a communication bus, and a combination of connection / separation of switches is determined. There has been proposed a failure diagnosis method for diagnosing an abnormality in a communication line by making a change and repeatedly determining whether communication is possible.

JP 2014-187542 A

In a communication system that employs a bus-type communication line in which multiple communication branches branch from the communication trunk line, if a short circuit or ground fault occurs in any of the communication branches, the entire system may not be able to communicate. There is sex. The failure diagnosis method described in Patent Document 1 needs to operate the entire communication system as a test mode, and is performed only at a specific timing, for example, when the communication system is activated. For this reason, there is a problem that a failure cannot be detected when a failure has not been detected by failure diagnosis performed at a specific timing and a failure has occurred thereafter.

The present disclosure has been made in view of such circumstances, and the object of the present disclosure is to detect a failure such as a short circuit and a ground fault in a bus-type communication line, and to connect a communication system and a connection for disconnecting the failure portion. An apparatus, a control device, a communication line blocking method, and a computer program are provided.

The communication system according to this aspect is a bus-type communication system in which a communication device is connected to each of a plurality of communication branches branched from a communication trunk line, and the plurality of communication devices communicate via the communication trunk line and the communication branch line. A current detection unit that detects a current flowing through each communication branch line, a switch that is provided in each communication branch line and that switches between energization and interruption of the communication branch line, and the switch based on the detection result of the current detection unit And a control unit that performs control to shut off.

The connection device according to this aspect is a communication line connection device including a plurality of connection units to which communication lines are connected, and includes a current detection unit that detects a current flowing through the communication line connected to each connection unit, and each communication. A switch that switches between energization and interruption of the wire, and a control unit that performs control to interrupt the switch based on a detection result of the current detection unit.

The control device according to the present aspect includes an acquisition unit that acquires a detection result from a current detection unit that detects currents flowing through a plurality of communication branch lines branched from a communication trunk line, and a detection result acquired by the acquisition unit, And a control unit that performs control to cut off a switch that switches between energization and cutoff provided in the communication branch line.

The communication line cutoff method according to this aspect detects currents flowing through a plurality of communication branches branched from the communication trunk line, and shuts off a switch that switches between energization and cutoff provided in each communication branch line based on the detection result.

The computer program according to this aspect acquires a detection result from a current detection unit that detects currents flowing through a plurality of communication branch lines branched from a communication trunk line in a computer, and is provided in each communication branch line based on the acquired detection result. The process which cuts off the switch which switches the supplied electricity and interruption | blocking is performed.

In addition, the present application can be realized not only as a connection device or a control device including such a characteristic processing unit, but also as a communication line blocking method using such a characteristic process as a step. It can be realized as a computer program to be executed by a computer. Further, it can be realized as a semiconductor integrated circuit that realizes part or all of the connection device or the control device, or can be realized as another device or system including the connection device or the control device.

According to the above, it is possible to detect a fault such as a short circuit or a ground fault in a bus-type communication line, and to block the fault location.

1 is a schematic diagram showing a configuration of a communication system according to Embodiment 1. FIG. 1 is a schematic diagram illustrating a network configuration of a communication system according to Embodiment 1. FIG. 1 is a schematic diagram illustrating a configuration of a connection device according to Embodiment 1. FIG. It is a schematic diagram for demonstrating the flow of the electric current at the time of communication in a communication system. It is a schematic diagram for demonstrating the flow of the electric current at the time of communication in a communication system. It is a schematic diagram for demonstrating the flow of the electric current at the time of communication in a communication system. 4 is a flowchart illustrating a procedure of a communication branch line blocking process performed by the connection device according to the first embodiment. 3 is a block diagram showing a configuration of a communication system according to Embodiment 2. FIG. 6 is a flowchart illustrating a procedure of a communication branch line blocking process performed by an ECU according to a second embodiment. It is a flowchart which shows the procedure of the signal output process for the interruption | blocking process which ECU which concerns on Embodiment 2 performs. 10 is a flowchart illustrating a procedure of a communication branch line blocking process performed by the connection device according to the second embodiment.

[Description of Embodiment of Present Disclosure]
First, embodiments of the present disclosure will be listed and described. Moreover, you may combine arbitrarily at least one part of embodiment described below.

(1) In the communication system according to this aspect, a communication device is connected to each of a plurality of communication branches branched from a communication main line, and a plurality of the communication devices communicate via the communication main line and the communication branch line. A communication system comprising: a current detection unit that detects a current flowing through each communication branch; a switch that is provided in each communication branch and that switches between energization and disconnection of the communication branch; and a detection result of the current detection unit. And a control unit that performs control to shut off the switch.

In this aspect, a plurality of communication devices communicate via a bus-type communication line in which a plurality of communication branch lines branch from a communication trunk line. Each communication branch is provided with a current detector that detects a current flowing through the communication branch, and a switch that switches between energization and interruption of the communication branch. Each switch is controlled to be cut off based on the current detection result by the current detection unit. As a result, the communication system detects the current of each communication branch line during normal communication by the communication device, determines the presence / absence of abnormality for each communication branch line, and shuts off the abnormal communication branch line with a switch. Can do.

(2) A connection device having a plurality of connection portions each connected to the communication branch line, the current detection unit and the switch, and a control device connected to the communication trunk line or the communication branch line and having the control unit. It is preferable that the connection device and the control device are connected via a communication line different from the communication trunk line and the communication branch line.

In this aspect, a current detection unit and a switch for each communication branch line are provided in the communication line connection device. In addition, the control device connected to the communication main line or the communication branch line is provided with a control unit that controls the switching of the switch, and the control device and the connection device are connected via a communication line different from the communication main line and the communication branch line. . Thereby, when an abnormality occurs and communication via the communication trunk line and the communication branch line becomes impossible, the control device and the connection device can communicate via another communication line, and the control device is switched Can be controlled.

(3) It is preferable to provide a connection device having a plurality of connection portions to which the communication branch lines are connected, the current detection portion, the switch, and the control portion.

In this aspect, the communication line connection device includes a current detection unit and a switch for each communication branch line, and a control unit that controls the switching of the switch. By consolidating these into one device, simplification of the device and reduction of wiring between devices can be expected.

(4) It is preferable that the said control part interrupts | blocks the said switch provided in the communication branch line in which the said current detection part detected the electric current exceeding a threshold value.

In this mode, the switch provided in the communication branch line where the current detection unit detects the current exceeding the threshold is cut off. Thereby, the communication branch line through which more current than usual flows can be cut off due to a short circuit or ground fault.

(5) An error detection unit that detects a communication error in the communication trunk line is provided, and after the error detection unit detects a communication error, current detection by the current detection unit and control of the switch by the control unit are performed. Is preferred.

In this embodiment, communication on the communication trunk line is monitored, and after detecting a communication error, current detection of the current detection unit and switch control of the control unit are performed. When there is no communication error, there is a high possibility that a communication line error has not occurred. Therefore, current detection and switch control are performed after detecting a communication error to reduce the processing load during normal operation. Can do.

(6) After all of the communication devices connected to a plurality of the communication branch lines stop communication after the error detection unit detects a communication error, signal output to the communication trunk line or the communication branch line is performed. It is preferable that a communication unit is provided, and the current detection unit detects a current when the signal output is performed.

In this aspect, after an error occurs in communication via the communication line, there is a possibility that the communication device connected to this communication line stops communication. If all communication devices stop communicating, the communication line will be unused, so even if a short circuit or ground fault occurs, current will not flow, and it may not be possible to detect anomalies based on current detection. . Therefore, when all communication devices stop communication after detecting a communication error, a signal is output to the communication line, and current detection is performed at this time, so that an abnormality can be detected even after the communication is stopped.

(7) It is preferable to provide a storage unit that stores a detection result of the current detection unit and / or a control result of the control unit.

In this mode, the detection result of the current detection unit and / or the control result of the switch by the control unit are stored. Thereby, for example, when the communication system is repaired, it is possible to easily determine the failure location of the communication line.

(8) The connection device according to this aspect is a communication line connection device including a plurality of connection units to which communication lines are connected, and a current detection unit that detects a current flowing through the communication line connected to each connection unit; And a switch that switches between energization and cutoff of each communication line, and a control unit that performs control to shut off the switch based on a detection result of the current detection unit.

In this aspect, as in aspect (1), when normal communication is performed by the communication device, the current of each communication branch is detected to determine whether there is an abnormality for each communication branch. A certain communication branch line can be interrupted by a switch.

(9) The control device according to this aspect is based on an acquisition unit that acquires a detection result from a current detection unit that detects currents flowing through a plurality of communication branches branched from a communication trunk line, and a detection result acquired by the acquisition unit. And a control unit that performs control to cut off a switch that switches between energization and interruption provided in each communication branch line.

(10) The communication line cutoff method according to this aspect detects currents flowing through a plurality of communication branch lines branched from the communication trunk line, and shuts off a switch that switches between energization and cutoff provided to each communication branch line based on the detection result. To do.

(11) The computer program according to the present aspect acquires a detection result from a current detection unit that detects currents flowing through a plurality of communication branch lines branched from a communication main line, and each communication is performed based on the acquired detection result. A process of shutting off a switch for switching between energization and shutoff provided on the branch line is performed.

[Details of Embodiment of the Present Disclosure]
A specific example of a communication system according to an embodiment of the present disclosure will be described below with reference to the drawings. In addition, this indication is not limited to these illustrations, is shown by the claim, and is intended that all the changes within the meaning and range equivalent to the claim are included.

(Embodiment 1)
<Network configuration>
FIG. 1 is a schematic diagram illustrating a configuration of a communication system according to the first embodiment. The communication system 100 according to the first embodiment has a configuration in which seven ECUs 2a to 2g mounted on the vehicle 1 are connected to the connection device 4 via communication lines 3a to 3g, respectively. The ECUs 2a to 2g are, for example, an ECU that controls the operation of the engine of the vehicle 1, an ECU that controls the locking / unlocking of the door, an ECU that controls the turning on / off of the light, an ECU that controls the operation of the airbag, and an ABS. Various ECUs such as an ECU that controls the operation of the (Antilock Brake System) may be included.

The connection device 4 has a plurality of connection portions (connectors) to which the communication lines 3a to 3g are connected. The connection device 4 is a device that electrically connects a plurality of connected communication lines 3a to 3g, and can be called a name such as a HUB or a junction box. The connection device 4 according to the present embodiment constitutes one bus type network by a plurality of connected communication lines 3a to 3g. The ECUs 2a to 2g can communicate with each other via the communication lines 3a to 3g and the connection device 4.

For example, the connection device 4 is disposed in the center of the vehicle 1, the ECU 2 a is disposed on the left side of the connection device 4, and the ECU 2 b is disposed on the right side of the connection device 4. For example, the ECU 2c is arranged on the left side of the front part of the vehicle 1, the ECU 2d is arranged in the center of the front part of the vehicle 1, and the ECU 2e is arranged on the right side of the front part of the vehicle 1. Further, for example, the ECU 2 f is arranged on the left side of the rear part of the vehicle 1, and the ECU 2 g is arranged on the right side of the rear part of the vehicle 1. Note that the arrangement of the ECUs 2a to 2g and the connection device 4 shown in FIG. 1 is an example, and the present invention is not limited to this. In the arrangement example of the illustrated device, for example, when an accident such as a collision occurs in the vehicle 1, the

ECUs

2a and 2b and the connection device 4 arranged in the center in the front-rear direction of the vehicle 1 are compared with the other ECUs 2c to 2g. It is hard to break down. In addition, the

communication lines

3a and 3b connecting the

ECUs

2a and 2b to the connection device 4 cause failures such as disconnection, short circuit, or ground fault as compared with the communication lines 3c to 3g connecting other ECUs 2 to the connection device 4. hard.

Therefore, in the present embodiment, the connection device 4 (internal wiring thereof) and the

communication lines

3a and 3b are handled as communication trunk lines, and the other communication lines 3c to 3g are handled as communication branch lines.

FIG. 2 is a schematic diagram illustrating a network configuration of the communication system 100 according to the first embodiment. In the present embodiment, the ECUs 2a to 2g perform communication in accordance with CAN communication standards. In the CAN communication standard, a bus-type network is configured using a two-wire communication line, a so-called twisted pair cable, and a differential signal corresponding to a voltage difference between the two wires is used for communication. In the present embodiment, the CAN bus has a set of communication trunk lines 5 and a plurality of sets of communication branch lines 6 branched from the communication trunk line 5. In the CAN communication standard, two ends of the communication trunk line 5 are connected via a terminating resistor R. The two termination resistors R are provided in the

ECUs

2a and 2b, respectively. A branch point between the communication trunk line 5 and the communication branch line 6 is provided inside the connection device 4.

The communication trunk line 5 shown in FIG. 2 includes the

communication lines

3 a and 3 b shown in FIG. Each communication branch line 6 shown in FIG. 2 includes the communication lines 3 c to 3 g shown in FIG. 1 and the internal wiring of the connection device 4.

<Device configuration>
FIG. 3 is a schematic diagram illustrating a configuration of the connection device 4 according to the first embodiment. The connection device 4 according to the present embodiment has a configuration in which, for example, a plurality of

connectors

43 and 44 for connecting the communication lines 3a to 3g are provided in a synthetic resin casing. The two connectors 43 provided in the connection device 4 are for connecting two

communication lines

3 a and 3 b corresponding to the communication trunk line 5. The plurality of connectors 44 included in the connection device 4 are for connecting a plurality of communication lines 3b to 3g corresponding to the communication branch line 6. However, in FIG. 3, only three connectors 44 are shown for simplification of the drawing.

In the connection device 4, the two connectors 43 are connected via two internal wirings 43 a constituting the communication trunk line 5. When the

communication lines

3a and 3b are connected to the two connectors 43, the one

communication lines

3a and 3b and the internal wiring 43a of the connection device 4 are electrically connected, and the communication trunk line 5 of the communication system 100 shown in FIG. Configure. The internal wiring 43 a of the connection device 4 branches at a plurality of locations, and the internal wiring 44 a is provided from the branch point to the connector 44. A set of two internal wirings 44a branched from the two internal wirings 43a is taken as a set, and a set of internal wirings 44a is connected to each connector 44. When the communication lines 3b to 3g are connected to the connector 44, the communication lines 3b to 3g are electrically connected to the internal wiring 44a, respectively, and constitute the communication branch line 6 of the communication system 100 shown in FIG.

Further, a switch SW and a current detection unit 45 are provided on each line of the internal wiring 44a. The switch SW is configured using, for example, a semiconductor switch such as a field effect transistor or a MOS (Metal Oxide Semiconductor) transistor, or a relay such as an electromagnetic relay or a solid state relay. The switch SW switches between energization and interruption of the internal wiring 44a. The current detection unit 45 detects the current value and direction of the current flowing through the internal wiring 44a. The current detection unit 45 may be configured to measure a potential difference between both ends of a resistor provided in the internal wiring 44a, for example, and acquire a current value based on the measured potential difference and the resistance value of the resistor. However, the current detection unit 45 may be configured to detect the current value of the current flowing through the internal wiring 44a, the direction of the current, and the like by other methods. In the present embodiment, the communication branch line 6 (communication lines 3b to 3g and internal wiring 44a) is a two-wire system, so that the connection device 4 has twice as many switches SW and current detection units 45 as the number of connectors 44. Provided.

The connection device 4 includes a control unit 41 and a storage unit 42. The control unit 41 can be configured using, for example, an IC (Integrated Circuit) such as a CPU (Central Processing Unit) or a microcomputer. The control unit 41 receives a current detection result from each current detection unit 45. Further, the control unit 41 outputs a control signal for switching between energization and cutoff for each switch SW. The control unit 41 detects an abnormality in each communication branch line 6 based on the detection result of the current detection unit 45, and disconnects the communication branch line 6 from the communication system 100 by cutting off the switch SW of the communication branch line 6 in which the abnormality is detected. Control. For example, the control unit 41 stores a threshold value for determining an abnormality in advance, and determines that an abnormality has occurred when the current value detected by the current detection unit 45 exceeds the threshold value.

The storage unit 42 is configured using, for example, an EEPROM (Electrically-Erasable-Programmable-Read-Only-Memory) or a rewritable nonvolatile memory element such as a flash memory. The control unit 41 can read and write data from and to the storage unit 42. When the control unit 41 detects an abnormality in the communication branch line 6, the control unit 41 writes log information regarding the abnormality in the storage unit 42. The log information stored in the storage unit 42 may include, for example, information indicating which of the communication branch lines 6 in which an abnormality is detected, a detection result of the current detection unit 45 when an abnormality is detected, and the like. The detection result in this case may include not only the detection result regarding the communication branch line 6 in which the abnormality is detected, but also the detection result regarding another communication branch line 6.

<Communication branch line blocking process>
4 to 6 are schematic diagrams for explaining the flow of current during communication in the communication system 100. FIG. In this figure, in order to simplify the description, there are only two communication branch lines 6 to which the

ECUs

2c and 2d are connected. Of the two lines included in the two-wire communication branch line 6, the line to which the high potential side of the differential signal is applied is the high potential side branch line 6h, and the line to which the low potential side of the differential signal is applied is the low potential. It is distinguished as a side branch line 6l. Similarly, two lines included in the two-wire communication trunk line 5 are distinguished as a high potential side trunk line 5h and a low potential side trunk line 5l. In addition, the flow of current during communication is indicated by broken-line arrows.

FIG. 4 shows the flow of current in the communication system 100 when no abnormality has occurred, that is, when it is normal. In this example, it is assumed that the ECU 2 c connected to one communication branch line 6 outputs a transmission signal to the communication branch line 6. In this case, the current flowing out from the ECU 2c to the high potential side branch line 6h of the communication branch line 6 flows through the high potential side trunk line 5h of the communication trunk line 5 to the termination resistor R, and from the termination resistor R to the low potential side trunk line of the communication trunk line 5. 5l and flows into the ECU 2c from the low potential side trunk line 5l through the low potential side branch line 6l.

FIG. 5 shows a current flow when a ground fault occurs in the low potential side branch line 6l of the communication branch line 6 to which the ECU 2d is connected. In this case, the current flowing out from the ECU 2c to the high potential side branch line 6h of the communication branch line 6 flows through the high potential side trunk line 5h of the communication trunk line 5 to the termination resistor R, and from the termination resistor R to the low potential side trunk line of the communication trunk line 5. 5l, flows from the low potential side trunk line 5l to the low potential side branch line 6l to which the ECU 2d is connected, and reaches the ground fault point. Further, since the low potential side branch line 6l to which the ECU 2d is connected is grounded, a current flows out from the ECU 2c to the low potential side branch line 61, and this current is connected to the ECU 2d from the low potential side trunk line 5l of the communication trunk line 5. It flows to the low potential side branch line 6l and reaches the ground fault point. That is, when a ground fault occurs in the communication branch line 6, a large current flows through the grounded low potential side branch line 61.

Based on the detection result of the current detection unit 45, the control unit 41 of the connection device 4 determines that a current exceeding the threshold value is flowing in the low potential side branch line 6l of the communication branch line 6 to which the ECU 2d is connected. In response to this determination, the control unit 41 performs control to switch the switch SW provided in the low potential side branch line 61 to the cut-off state, and cuts off the low potential side branch line 61. At this time, it is preferable that the control unit 41 also performs control to shut off the switch SW for the low potential side branch line 61 and the pair of high potential side branch lines 6h that are determined to have a large current flowing.

In the example shown in FIG. 5, the control unit 41 may determine that a current exceeding the threshold value flows in the high potential side branch line 6 h or the low potential side branch line 6 l of the communication branch line 6 to which the ECU 2 c is connected. In this case, the control unit 41 may perform control for blocking the communication branch line 6 to which the ECU 2c is connected.

FIG. 6 shows a current flow when the high potential side branch line 6h and the low potential side branch line 6l of the communication branch line 6 to which the ECU 2d is connected are short-circuited. In this case, the current flowing out from the ECU 2c to the high potential side branch line 6h of the communication branch line 6 flows from the high potential side trunk line 5h of the communication trunk line 5 to the high potential side branch line 6h of the communication branch line 6 to which the ECU 2d is connected to the short circuit portion. It reaches. Further, this current flows to the low potential side branch line 6l of the communication branch line 6 to which the ECU 2d is connected via the short-circuited portion, and flows from the low potential side branch line 6l to the low potential side trunk line 5l of the communication trunk line 5, thereby lowering the low potential side trunk line 51 Flows into the low potential branch 6l to which the ECU 2c is connected and flows into the ECU 2c. In this case, since a current flows from the high potential side to the low potential side without passing through the termination resistor R, a large current flows through each current path.

Based on the detection result of the current detection unit 45, the control unit 41 of the connection device 4 has a current exceeding a threshold value flowing in the high potential side branch line 6h and the low potential side branch line 6l of the communication branch line 6 to which the ECU 2d is connected. judge. In response to this determination, the control unit 41 performs control to switch the switch SW provided in the high potential side branch line 6h and the low potential side branch line 6l to the cut-off state, and the high potential side branch line 6h and the low potential connected to the ECU 2d. The side branch line 6l is shut off.

In the example shown in FIG. 6, the control unit 41 may determine that a current exceeding the threshold value flows in the high potential side branch line 6 h or the low potential side branch line 6 l of the communication branch line 6 to which the ECU 2 c is connected. In this case, the control unit 41 may perform control for blocking the communication branch line 6 to which the ECU 2c is connected.

FIG. 7 is a flowchart showing the procedure of the disconnection process of the communication branch line 6 performed by the connection device 4 according to the first embodiment. The control unit 41 of the connection device 4 according to the first embodiment causes the plurality of current detection units 45 to detect the current of the communication branch line 6 and acquires detection results such as current values from the current detection unit 45 (step S1). . The control unit 41 compares the current value (absolute value) detected by each current detection unit 45 with a previously stored threshold value, and determines whether or not the current value exceeds the threshold value (step S2). If the current value does not exceed the threshold value for all detection results (S2: NO), the control unit 41 determines that no abnormality has occurred in the communication branch line 6, and advances the process to step S3.

The control unit 41 repeatedly performs the current detection of each communication branch line 6 by the current detection unit 45 at a cycle of, for example, several milliseconds to several seconds. The control unit 41 that has determined that there is no abnormality in the communication branch line 6 waits for a predetermined time that defines the current detection cycle (step S3), returns the process to step S1, and performs the current detection by the current detection unit 45 in the predetermined cycle. Repeat with.

When the current value exceeds the threshold value for at least one detection result (S2: YES), the control unit 41 shuts off the switch SW of the communication branch line 6 provided with the current detection unit 45 that detects the current value exceeding the threshold value. The communication branch line 6 is shut off by outputting a signal for switching to (step S4). Next, the control unit 41 performs current detection by the current detection unit 45 (step S5). At this time, the control unit 41 may perform current detection regardless of the current detection cycle. The control part 41 determines whether the electric current value which each electric current detection part 45 detected exceeds a threshold value (step S6). When the current value exceeds the threshold for at least one detection result (S6: YES), the control unit 41 returns the process to step S4, and repeatedly performs the disconnection of the communication branch line 6 and further current detection and determination.

When the current value does not exceed the threshold value for all the detection results (S6: NO), the control unit 41 provides information indicating which of the communication branch lines 6 is blocked and the current detection unit 45 when the blocking is performed. Log information including the detection result and the like is generated, the generated log information is stored in the storage unit 42 (step S7), and the process ends.

<Summary>
The communication system 100 according to Embodiment 1 having the above configuration is configured such that a plurality of ECUs 2a to 2g communicate via a bus-type communication line in which a plurality of communication branch lines 6 are branched from a communication trunk line 5. Each communication branch line 6 is provided with a current detector 45 that detects a current flowing through the communication branch line 6 and a switch SW that switches between energization and interruption of the communication branch line 6. Each switch SW is controlled to be cut off based on the current detection result by the current detection unit 45. Thus, the communication system 100 detects the current of each communication branch line 6 during normal communication by the ECUs 2a to 2g, determines the presence / absence of an abnormality for each communication branch line 6, and determines the communication branch line 6 having an abnormality. It can be shut off by the switch SW.

In the communication system 100 according to the first embodiment, the connection device 4 includes the current detection unit 45 and the switch SW provided for each communication branch line 6 and the control unit 41 that controls them. By consolidating the plurality of current detection units 45 and the switches SW and the control unit 41 into one device, simplification of the system configuration and reduction of wiring between devices can be expected.

Further, the connection device 4 according to the first embodiment cuts off the switch SW provided in the communication branch line 6 where the current detection unit 45 has detected a current exceeding the threshold value. Thereby, the communication branch line 6 in which more current than usual is flowing due to a short circuit or a ground fault can be cut off.

In addition, the connection device 4 according to the first embodiment stores the control result of the switch SW by the control unit 41 and the detection result of the current detection unit 45 in the storage unit 42 as log information. Thereby, when repairing the communication system 100, for example, the operator can easily determine the failure location of the communication branch line 6 by browsing the log information.

In the present embodiment, the communication system 100 mounted on the vehicle 1 has been described as an example. However, the communication system 100 is not limited to the one mounted on the vehicle 1, for example, on a moving body such as a ship or an aircraft. The same configuration can be adopted for various communication systems such as an installed communication system or a communication system installed in an office or factory. Further, the number and arrangement of the ECUs 2a to 2g of the vehicle 1 shown in FIG. 1 are merely examples, and are not limited thereto. The two

ECUs

2a and 2b are connected to the communication trunk line 5. However, the present invention is not limited to this, and all the ECUs 2a to 2g may be connected to the communication branch line 6. In the case of this configuration, the termination resistor R may be provided in the connection device 4.

(Embodiment 2)
FIG. 8 is a block diagram showing a configuration of the communication system 200 according to the second embodiment. In the communication system 200 according to the second embodiment, one ECU 202a connected to the communication trunk line 5 communicates with the connection device 204 via the dedicated communication line 203, and acquires a current detection result from the connection device 204. At the same time, the switch SW is controlled to be turned off.

The connection device 204 according to the second embodiment does not include the storage unit 42 of the connection device 4 according to the first embodiment, and includes a communication unit 242 that performs communication with the ECU 202a via the communication line 203. The communication performed by the communication unit 242 with the ECU 202a does not have to conform to the CAN communication standard, and various serial communication or parallel communication can be employed. The communication unit 242 gives the information received from the ECU 202a to the control unit 41 and transmits the information given from the control unit 41 to the ECU 202a.

The control unit 41 of the connection device 204 according to the second embodiment does not perform the above-described presence / absence determination based on the detection result of the current detection unit 45 and the cutoff control of the switch SW based on the determination result. Instead of this, the control unit 41 according to the second embodiment switches the switch SW in accordance with a process of periodically acquiring the detection result of the current detection unit 45 and transmitting it to the ECU 202a, and a cutoff command given from the ECU 202a. Perform a blocking process.

The ECU 202a according to Embodiment 2 includes a control unit 221, a storage unit 222, a first communication unit 223, and a second communication unit 224. In FIG. 8, among the functional blocks provided in the ECU 202a, functional blocks relating to the disconnection process of the communication branch line 6 are extracted and shown, and functional blocks relating to the control of the vehicle 1 and the like are not shown. The control unit 221 is configured using an arithmetic processing device such as a CPU or MPU (Micro-Processing Unit), for example, and performs various arithmetic processes by reading and executing the program 222a stored in the storage unit 222.

The storage unit 222 is configured using a nonvolatile memory element such as a flash memory or an EEPROM. The storage unit 222 stores a program 222a executed by the control unit 221 and data necessary for executing the program 222a. The program 222a may be written in the storage unit 222 in the manufacturing stage of the ECU 202a, for example, or the program recorded in the recording medium 209 such as a memory card or an optical disk may be read out and stored in the storage unit 222, for example. Further, for example, the recording device may read out what is recorded on the recording medium 209 and write it in the storage unit 222 of the ECU 202a. The storage unit 222 stores log information 222b when the communication branch line 6 is cut off.

The 1st communication part 223 is connected to the communication line which comprises an in-vehicle network, and communicates according to the communication standard of CAN. In this Embodiment, the 1st communication part 223 is connected to the communication line which comprises the communication trunk line 5 among the communication lines which comprise a vehicle interior network. The first communication unit 223 performs transmission by converting the transmission information given from the control unit 221 into an electrical signal and outputting the electric signal to the communication main line 5 and receives the signal by sampling and acquiring the potential of the communication main line 5. And the received information is given to the control unit 221.

The second communication unit 224 is connected to the connection device 204 via the communication line 203 and performs one-to-one communication with the connection device 204. The second communication unit 224 gives the information received from the connection device 204 to the control unit 221 and transmits the information given from the control unit 221 to the connection device 204.

The ECU 202a according to the second embodiment performs processing for determining whether or not an accident such as a collision has occurred in the vehicle 1. For example, the vehicle 1 is equipped with an airbag that protects an occupant when an accident such as a collision occurs, and an ECU that activates the airbag. This ECU detects an impact applied to the vehicle 1 by a sensor, for example, and operates the airbag. The ECU 202a obtains an impact detection result or airbag operation information from the ECU that operates the airbag by communication via the network of the vehicle 1, and an accident such as a collision occurs in the vehicle 1 based on the information. It can be determined whether or not. For example, the ECU 202a determines that a collision has occurred in the vehicle 1 when information indicating that the airbag has been activated is received through communication. Note that the ECU 202a may receive information from the ECU that operates the airbag by communication via the communication trunk line 5 and the communication branch line 6, or may receive information by other communication methods.

Further, the ECU 202a monitors the status of communication via the communication trunk line 5 and the communication branch line 6 in the first communication unit 223. Specifically, the ECU 202a determines whether or not an error has occurred in communication via the communication trunk line 5 and the communication branch line 6. When the ECU 202a determines that an accident such as a collision has occurred in the vehicle 1 and determines that an error has occurred in communication via the communication trunk line 5 and the communication branch line 6, the current detection unit 45 is connected to the connection device 204. The second communication unit 224 performs communication requesting acquisition of the detection result. In response to this request, the connection device 204 acquires the detection result of the current detection unit 45 provided in each communication branch line 6, and transmits the acquired detection result from the communication unit 242 to the ECU 202a. The ECU 202a determines the communication branch line 6 to be cut off based on the detection result of the current acquired from the connection device 204, and transmits a command to cut the switch SW of the decided communication branch line 6 to the connection device 204. The connection device 204 that has received the shut-off command performs control to shut off the switch SW provided in the communication branch line 6 specified by the shut-off command.

After the communication branch line 6 is cut off, the ECU 202a requests the connection device 204 again to obtain the detection result of the current detection unit 45 for confirmation. When the ECU 202a that has acquired the current detection result again determines that the current value does not exceed the threshold value and the communication branch 6 that has short-circuited or grounded has been successfully disconnected, the ECU 202a displays information on the communication branch 6 that has been disconnected. The log information 222b is stored in the storage unit 222. On the other hand, if the current value exceeds the threshold value even in the detection result reacquired, the ECU 202a further cuts off the communication branch line 6. The ECU 202a repeatedly obtains the current detection result and shuts off the communication branch line 6, and shuts off all the communication branch lines 6 in which a short circuit or a ground fault occurs.

However, the communication error of the communication trunk line 5 and the communication branch line 6 is maintained for a predetermined time while the ECU 202a repeatedly obtains the current detection result and interrupts the communication branch line 6. There is a possibility that the other ECUs 2b to 2g connected to the communication branch line 6 stop the communication process. When the other ECUs 2b to 2g stop the communication process, no transmission signal is output to the communication trunk line 5 and the communication branch line 6, so that no current flows through the communication trunk line 5 and the communication branch line 6, and the current detection unit 45 Overcurrent cannot be detected. This state corresponds to a case where a bus-off state is reached in the CAN communication standard.

Therefore, the ECU 202a according to the second embodiment outputs a signal to the communication trunk line 5 at the first communication unit 223 when the other ECUs 2b to 2g have stopped the communication process. As a result, since the current from the ECU 202a flows through the communication trunk line 5 and the communication branch line 6, an overcurrent can be detected by the current detection unit 45 provided in the communication branch line 6. At this time, the signal output from the first communication unit 223 does not need to conform to the CAN communication standard, and may be any signal.

FIG. 9 is a flowchart showing the procedure of the disconnection process of the communication branch line 6 performed by the ECU 202a according to the second embodiment. The control unit 221 of the ECU 202a according to Embodiment 2 determines whether an accident such as a collision has occurred in the vehicle 1 based on information from the ECU that operates the airbag of the vehicle 1 received by the first communication unit 223. Is determined (step S21). When it is determined that an accident has occurred (S21: YES), the control unit 221 determines whether or not an error has occurred in the communication of the communication trunk line 5 and the communication branch line 6 in the first communication unit 223 (step S22). . When it is determined that no accident has occurred in the vehicle 1 (S21: NO), or when it is determined that no error has occurred in communication between the communication trunk line 5 and the communication branch line 6 (S22: NO), the control unit 221. Returns the process to step S21.

When it is determined that an error has occurred in communication between the communication trunk line 5 and the communication branch line 6 (S22: YES), the control unit 221 communicates with the connection device 204 at the second communication unit 224, and the current detection unit 45 An acquisition request for the current detection result of the communication branch line 6 is transmitted to the connection device 204 (step S23). The control part 221 acquires the current detection result of the current detection part 45 by receiving the information transmitted from the connection device 204 in response to the acquisition request by the second communication part 224 (step S24). The control unit 221 compares the current value detected by each current detection unit 45 with a previously stored threshold value, and determines whether or not the current value exceeds the threshold value (step S25). When the current value does not exceed the threshold value for all detection results (S25: NO), the control unit 221 determines that no abnormality has occurred in the communication branch line 6, and ends the process.

When the current value exceeds the threshold value for at least one detection result (S25: YES), the control unit 221 issues a command to shut off the communication branch line 6 provided with the current detection unit 45 that detects the current value exceeding the threshold value. 2 The communication unit 224 transmits the data to the connection device 204 (step S26). Subsequently, the control part 221 transmits the acquisition request | requirement of the electric current detection result of the communication branch line 6 by the electric current detection part 45 to the connection apparatus 204 (step S27). The control unit 221 acquires the current detection result transmitted by the connection device 204 in response to this acquisition request (step S28). The control unit 221 determines whether or not the current value detected by each current detection unit 45 exceeds a threshold value (step S29). When the current value exceeds the threshold for at least one detection result (S29: YES), the control unit 221 returns the process to step S26, and repeatedly performs the disconnection of the communication branch line 6 and further current detection and determination.

When the current value does not exceed the threshold value for all the detection results (S29: NO), the control unit 221 provides information indicating which communication branch line 6 is blocked and the current detection unit 45 when the blocking is performed. The log information 222b including the detection result and the like is generated, the generated log information 222b is stored in the storage unit 222 (step S30), and the process is terminated.

FIG. 10 is a flowchart illustrating a procedure of signal output processing for shut-off processing performed by the ECU 202a according to the second embodiment. This process is a process performed in parallel with the blocking process shown in FIG. The control unit 221 of the ECU 202a according to Embodiment 2 determines whether or not an accident such as a collision has occurred in the vehicle 1 (step S41). When it is determined that an accident has occurred (S41: YES), the control unit 221 determines whether or not an error has occurred in communication between the communication trunk line 5 and the communication branch line 6 in the first communication unit 223 (step S42). . When it is determined that no accident has occurred in the vehicle 1 (S41: NO), or when it is determined that no error has occurred in communication between the communication trunk line 5 and the communication branch line 6 (S42: NO), the control unit 221. Returns the process to step S41.

When it is determined that an error has occurred in the communication between the communication trunk line 5 and the communication branch line 6 (S42: YES), the control unit 221 monitors the communication via the communication trunk line 5 and the communication branch line 6 with the first communication unit 223. Thus, it is determined whether or not communication by the other ECUs 2b to 2g is stopped (step S43). When communication has not stopped (S43: NO), control part 221 judges whether interception of communication branch 6 in which a short circuit or a ground fault occurred has been completed (Step S44). When the interruption of the communication branch line 6 has not been completed (S44: NO), the control unit 221 returns the process to step S43 and waits until the communication is stopped or the interruption is completed. When interruption | blocking of the communication branch line 6 is completed (S44: YES), the control part 221 complete | finishes a process.

When communication of the other ECUs 2b to 2g is stopped (S43: YES), the control unit 221 starts outputting signals to the communication trunk line 5 at the first communication unit 223 (step S45), and then the control unit 221 Then, it is determined whether or not the interruption of the communication branch line 6 in which a short circuit or a ground fault has occurred has been completed (step S46). When the interruption of the communication branch line 6 is not completed (S46: NO), the control unit 221 continues to output the signal until the interruption is completed. When the blocking is completed (S46: YES), the control unit 221 stops outputting the signal from the first communication unit 223 (step S47) and ends the process.

FIG. 11 is a flowchart showing the procedure of the disconnection process of the communication branch line 6 performed by the connection device 204 according to the second embodiment. The control unit 41 of the connection device 204 according to Embodiment 2 determines whether or not the communication unit 242 has received an acquisition request for the current detection result from the ECU 202a (step S51). When the current detection result acquisition request is received (S51: YES), the control unit 41 causes the plurality of current detection units 45 to detect the current of the communication branch line 6, and obtains detection results such as current values from the current detection unit 45. Obtain (step S52). The control unit 41 transmits the current detection result acquired in step S52 to the ECU 202a through the communication unit 242 (step S53), and returns the process to step S51.

When the acquisition request of the current detection result is not received from the ECU 202a (S51: NO), the control unit 41 determines whether or not the communication unit 242 has received a disconnection command for the communication branch line 6 from the ECU 202a (step S54). ). When the blocking command has not been received (S54: NO), the control unit 41 returns the process to step S51. When the cutoff command is received (S54: YES), the control unit 41 outputs a signal for shutting off the switch SW of the communication branch 6 designated low in the cutoff command, thereby blocking the communication branch 6 (step S55). The process returns to step S51.

In the communication system 200 according to the second embodiment configured as described above, the current detector 45 that detects the current of each communication branch line 6 and the switch SW that cuts off each communication branch line 6 are provided in the connection device 204, and the current detection result The ECU 202a performs a process for controlling the shutoff of the switch SW based on the above. The ECU 202 a and the connection device 204 are connected via a communication line 203 different from the communication trunk line 5 and the communication branch line 6, and a current detection result, a switch SW cutoff command, and the like are transmitted and received via the communication line 203. As a result, when an accident such as a collision occurs in the vehicle 1 and communication via the communication trunk line 5 and the communication branch line 6 becomes impossible, the ECU 202a and the connection device 204 communicate with each other via another communication line 203. The ECU 202a can perform the cutoff control of the switch SW.

Further, the ECU 202a according to the second embodiment monitors communication in the communication trunk line 5 and the communication branch line 6, and after obtaining a communication error, obtains a current detection result of the current detection unit 45 and performs control for cutting off the switch SW. When there is no communication error, there is a high possibility that no abnormality has occurred in the communication trunk line 5 and the communication branch line 6. Therefore, the ECU 202a and the switch SW are controlled by detecting the current and controlling the switch SW after the communication error is detected. The connection device 204 can reduce the processing load during normal operation.

Further, the ECU 202a according to the second embodiment causes the first communication unit 223 to communicate with the communication trunk line 5 when the other ECUs 2b to 2g stop communicating after an error has occurred in communication via the communication trunk line 5 and the communication branch line 6. Output a signal. As a result, the ECU 202a outputs a signal to the communication trunk line 5 to cause the current to flow when the communication of the other ECUs 2b to 2g stops and no current flows to the communication trunk line 5 and the communication branch line 6. It becomes possible to detect the current of the communication branch line 6.

In the second embodiment, the ECU 202a determines whether or not an accident such as a collision has occurred in the vehicle 1. However, the present invention is not limited to this, and the ECU 202a does not determine whether or not an accident has occurred. May be. The method for determining the occurrence of an accident by the ECU 202a is not only a method based on information from the ECU that operates the airbag, but also any other method, for example, the ECU 202a includes an acceleration sensor and detects an impact applied to the vehicle 1. It may be adopted.

In addition, the ECU 202a is configured to start the process of acquiring the current detection result by the current detection unit 45 and cutting off the communication branch line 6 when a communication error is detected in the communication trunk line 5 and the communication branch line 6. It is not a thing. The ECU 202a may be configured not to detect a communication error. In this case, the ECU 202a may start processing for obtaining a current detection result and cutting off the communication branch line 6 in response to the occurrence of an accident in the vehicle 1 regardless of the presence or absence of a communication error. Further, the ECU 202a may acquire the current detection result periodically, for example, regardless of whether the vehicle 1 has an accident or a communication error.

The ECU 202a is configured to output a signal to the communication trunk line 5 in the first communication unit 223 when the communication of the other ECUs 2b to 2g is stopped, but is not limited thereto. For example, the ECU 202a may be configured to stop the process of acquiring the current detection result and cutting off the communication branch line 6 without outputting a signal to the communication trunk line 5 when communication of the other ECUs 2b to 2g is stopped.

Since other configurations of the communication system 200 according to the second embodiment are the same as those of the communication system 100 according to the first embodiment, the same parts are denoted by the same reference numerals and detailed description thereof is omitted.

Each device in the communication system includes a computer including a microprocessor, a ROM, a RAM, and the like. An arithmetic processing unit such as a microprocessor reads and executes a computer program including some or all of the steps of the sequence diagrams or flowcharts as shown in FIGS. 9 to 11 from a storage unit such as a ROM and a RAM. . Each of the computer programs of the plurality of apparatuses can be installed from an external server apparatus or the like. In addition, the computer programs of the plurality of devices are distributed in a state where they are stored in a recording medium such as a CD-ROM, a DVD-ROM, or a semiconductor memory.

It should be considered that the embodiment disclosed this time is illustrative in all respects and not restrictive. The scope of the present disclosure is shown not by the above-described meaning but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 Vehicle 2a to 2g ECU (communication device)
3a to 3g Communication line 4 Connection device 5 Communication trunk line 5l Low potential side trunk line 5h High potential side trunk line 6 Communication branch line 6l Low potential side branch line 6h High potential side branch line 41 Control unit 42 Storage unit 43 Connector 43a Internal wiring 44 Connector 44a Internal wiring 45 current detection unit 100 communication system 200 communication system 202a ECU (control device)
203 Communication Line 204 Connection Device 209 Recording Medium 221 Control Unit (Error Detection Unit)
222 storage unit 222a program 222b log information 223 first communication unit (communication unit)
224 Second communication unit 242 Communication unit R Termination resistor SW switch

Claims

A communication system is connected to each of a plurality of communication branches branched from a communication trunk line, and a plurality of the communication apparatuses are bus-type communication systems that communicate via the communication trunk line and the communication branch lines,
A current detection unit for detecting a current flowing through each communication branch line;
A switch that is provided in each communication branch line and switches between energization and interruption of the communication branch line;
And a control unit that performs control to shut off the switch based on a detection result of the current detection unit.
A plurality of connection parts each connected to the communication branch line, a connection device having the current detection part and the switch;
A control device connected to the communication trunk line or the communication branch line and having the control unit;
The communication system according to claim 1, wherein the connection device and the control device are connected via a communication line different from the communication trunk line and the communication branch line.
2. The communication system according to claim 1, further comprising: a connection device having a plurality of connection portions each connected to the communication branch line, and the current detection unit, the switch, and the control unit.
The communication system according to any one of claims 1 to 3, wherein the control unit shuts off the switch provided in a communication branch line in which the current detection unit detects a current exceeding a threshold value.
An error detection unit for detecting a communication error in the communication trunk line;
5. The communication system according to claim 1, wherein after the error detection unit detects a communication error, the current detection unit detects a current and the control unit controls the switch. 6. .
A communication unit that outputs a signal to the communication trunk line or the communication branch line when all the communication devices connected to the plurality of communication branch lines stop communication after the error detection unit detects a communication error; Prepared,
The communication system according to claim 5, wherein the current detection unit detects a current when the signal output is performed.
The communication system according to any one of claims 1 to 6, further comprising a storage unit that stores a detection result of the current detection unit and / or a control result of the control unit.
A communication line connection device comprising a plurality of connection portions to which communication lines are connected,
A current detection unit that detects a current flowing through a communication line connected to each connection unit;
A switch for switching between energization and interruption of each communication line;
And a control unit that performs control to shut off the switch based on a detection result of the current detection unit.
An acquisition unit that acquires a detection result from a current detection unit that detects currents flowing through a plurality of communication branch lines branched from the communication main line,
A control unit comprising: a control unit that performs control to shut off a switch that switches between energization and cutoff provided in each communication branch line based on a detection result acquired by the acquisition unit.
Detects currents flowing through multiple communication branches that branch from the main trunk line,
A communication line blocking method for blocking a switch for switching between energization and blocking provided in each communication branch line based on a detection result.
On the computer,
Obtain the detection result from the current detection unit that detects the current flowing through the multiple communication branches that branch from the communication trunk line,
A computer program for performing a process of shutting off a switch for switching between energization and shutoff provided in each communication branch line based on an obtained detection result.