JP2022144949A - Communication system, mobile body, communication control method and program - Google Patents

Abstract

To provide a communication system, a mobile body, a communication control method, and a program.SOLUTION: A communication system comprises a first communication device (main ECU 210) and a second communication device (sub ECU 220) connected together to a first CAN communication network 101 and a second CAN communication network 1. The first communication device transmits first data to the second communication device through the first CAN communication network, receives second data transmitted from the second communication device through the second CAN communication network, and switches the CAN communication network used for transmitting the first data to the second CAN communication network from the first CAN communication network when a positive response to the transmission of the first data through the first CAN communication network is not obtained through the first CAN communication network.SELECTED DRAWING: Figure 3

Description

The present invention relates to a communication system, a mobile object, a communication control method, and a program.

In Patent Document 1, in a communication system including a plurality of ECUs connected to two CAN buses, when communication becomes difficult with any of the two CAN buses, each ECU sends only a basic message to the normal CAN bus. to be sent.
[Prior art documents]
[Patent Literature]
[Patent Document 1] JP-A-2008-271040

In a first aspect, a communication system is provided. The communication system comprises a first communication device and a second communication device connected together to a first CAN communication network and a second CAN communication network. The first communication device transmits first data to the second communication device over the first CAN communication network and receives second data transmitted from the second communication device over the second CAN communication network. The first communication device selects the CAN communication network used for transmission of the first data from the first CAN communication network when a positive response to the transmission of the first data through the first CAN communication network is not obtained through the first CAN communication network. Switch to the second CAN communication network.

The first communication device may not transmit data over the second CAN communication network and may not receive data over the first CAN communication network unless it fails to receive an acknowledgment from the second communication device.

Communication devices connected to the first CAN communication network and the second CAN communication network may be only the first communication device and the second communication device.

The first data may be data of a first type. The first CAN communication network may be the CAN communication network used by the first communication device to transmit the first type of data. The second CAN communication network may be a CAN communication network used by the first communication device to transmit data of a second type different from the first type. The first communication device may transmit the third data of the second type to the second communication device over the second CAN communication network. When a positive response to the transmission of the third data through the second CAN communication network is not obtained through the second CAN communication network, the CAN communication network used for the transmission of the second type of data is changed from the second CAN communication network to the first CAN communication network. You can switch to

The first communication device may determine whether the data is the first type data or the second type data based on the value of the ID field of the data frame transmitted through the first CAN communication network or the second CAN communication network. .

The first communication device may not transmit data over the second CAN communication network and may not receive data over the first CAN communication network unless it fails to receive an acknowledgment from the second communication device.

The communication system may further comprise a third communication device connected together to the first CAN communication network and the second CAN communication network. The first communication device may transmit the first data to the second communication device and the third communication device over the first CAN communication network. The first communication device may receive fourth data transmitted from the third communication device over the second CAN communication network.

The first CAN communication network is a CAN communication network used by the first communication device to transmit data in the first period, and is a CAN communication network used by the first communication device to receive data in the second period, good. The second CAN communication network is a CAN communication network used by the first communication device to receive data in the first period, and is a CAN communication network used by the first communication device to transmit data in the second period, good. The first communication device transmits the first data to the second communication device and the third communication device through the first CAN communication network in the first period, and sends an acknowledgment to the transmission of the first data through the first CAN communication network. The CAN communication network used for transmitting the first data may be switched from the first CAN communication network to the second CAN communication network when the data is not acquired through the first CAN communication network. In the second period, the first communication device transmits the fifth data to the second communication device and the third communication device through the second CAN communication network, and sends an acknowledgment to the transmission of the fifth data through the second CAN communication network. The CAN communication network used for transmitting the fifth data may be switched from the second CAN communication network to the first CAN communication network when it is not obtained through the second CAN communication network.

The first CAN communication network is a CAN communication network used by the first communication device to transmit data, and the second communication device and the third communication device receive data transmitted from the first communication device through the first CAN communication network. It may be a CAN communication network used to The second CAN communication network is a CAN communication network used by the second communication device and the third communication device to transmit data, and is used by the first communication device by temporally switching between data transmission and data reception. It may be a CAN communication network that When the first communication device transmits the sixth data to the second communication device and the third communication device through the second CAN communication network, the second CAN communication network sends an acknowledgment to the transmission of the sixth data through the second CAN communication network. the CAN communication network used for transmitting the sixth data may be switched from the second CAN communication network to the first CAN communication network if the data is not acquired through the second CAN communication network.

The first data may be data of a first type. The first CAN communication network may be the CAN communication network used by the first communication device to transmit the first type of data. The second CAN communication network may be a CAN communication network used by the first communication device to transmit data of a second type different from the first type. The first communication device may transmit the second type of third data to the second communication device and the third communication device through the second CAN communication network. When a positive response to the transmission of the third data through the second CAN communication network is not obtained through the second CAN communication network, the CAN communication network used for the transmission of the second type of data is changed from the second CAN communication network to the first CAN communication network. You can switch to

The first communication device may be capable of communicating with a fourth communication device connected by a third communication network. Neither the second communication device nor the third communication device may be connected to the third communication network. The second communication device and the third communication device may be communication devices that communicate with the fourth communication device via the first communication device.

The first data may be data of a first type. The first CAN communication network may be the CAN communication network used by the first communication device to transmit the first type of data. The second CAN communication network may be a CAN communication network used by the first communication device to transmit data of a second type different from the first type. The first communication device may transmit the third data of the second type to the second communication device over the second CAN communication network. When a positive response to the transmission of the third data through the second CAN communication network is not obtained through the second CAN communication network, the CAN communication network used for the transmission of the second type of data is changed from the second CAN communication network to the first CAN communication network. You can switch to

The first CAN communication network is a CAN communication network used by the first communication device to transmit data in the first period, and is a CAN communication network used by the first communication device to receive data in the second period, good. The second CAN communication network is a CAN communication network used by the first communication device to receive data in the first period, and is a CAN communication network used by the first communication device to transmit data in the second period, good. The first communication device transmits the first data to the second communication device through the first CAN communication network in the first time period, and obtains a positive response to the transmission of the first data through the first CAN communication network through the first CAN communication network. If not, the CAN communication network used for transmitting the first data may be switched from the first CAN communication network to the second CAN communication network. The first communication device transmits the fifth data to the second communication device through the second CAN communication network in the second period, and obtains a positive response to the transmission of the fifth data through the second CAN communication network through the second CAN communication network. If not, the CAN communication network used for transmitting the fifth data may be switched from the second CAN communication network to the first CAN communication network.

The mobile object may be a vehicle.

In a second aspect, a mobile object is provided. A mobile includes the communication device described above.

In a third aspect, a communication control method is provided. The communication control method is such that a first communication device connected to both a first CAN communication network and a second CAN communication network transmits first data through the first CAN communication network to a second CAN communication network connected to both the first CAN communication network and the second CAN communication network. 2 transmitting to a communication device. The communication control method comprises a first communication device receiving second data transmitted from a second communication device over a second CAN communication network. In the communication control method, when a positive response to transmission of the first data through the first CAN communication network is not obtained through the first CAN communication network, the CAN communication network used for transmission of the first data is selected from the first CAN communication network. Switching to the 2CAN communication network.

In a fourth aspect, a program is provided. The program causes the computer to function as the first communication device. The first communication device is connected to the first CAN communication network and the second CAN communication network. The program causes the computer to transmit the first data through the first CAN communication network to the second communication device connected to the first CAN communication network and the second CAN communication network, and transmit the second data transmitted from the second communication device to the second CAN communication network. be received over a communications network. The program instructs the computer to select the CAN communication network used for transmission of the first data from the first CAN communication network when a positive response to the transmission of the first data through the first CAN communication network is not obtained through the first CAN communication network. Switch to the second CAN communication network.

It should be noted that the above summary of the invention does not list all the necessary features of the invention. Subcombinations of these feature groups can also be inventions.

1 schematically shows a system configuration of a communication system 200 provided in a vehicle 20 according to one embodiment; An example of the format of the data frame prescribed|regulated by CAN protocol is shown. 4 is a diagram for explaining communication control between a main ECU 210 and a sub ECU 220 in one form; FIG. 3 is a diagram for explaining communication control between a main ECU 210, a sub ECU 230, and a sub ECU 230 in one form; FIG. 4 shows an example of a flowchart showing a procedure related to a communication control method executed by a main ECU 210. FIG. FIG. 5 is a diagram for explaining a first modification of communication control between main ECU 210 and sub ECU 220; FIG. 5 is a diagram for explaining a first modification of communication control between main ECU 210 and sub-ECUs 230 and 240; FIG. 5 is a diagram for explaining a modification of communication control between main ECU 210 and sub-ECUs 230 and 240; FIG. 5 is a diagram for explaining a second modification of communication control between main ECU 210 and sub ECU 220; 2000 illustrates an example computer 2000 in which embodiments of the present invention may be implemented in whole or in part.

Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. Also, not all combinations of features described in the embodiments are essential for the solution of the invention.

FIG. 1 schematically shows the system configuration of a communication system 200 provided in a vehicle 20 according to one embodiment. The communication system 200 includes a communication device 203 including a TCU 201 and an antenna 202, a main ECU 210, a sub ECU 220, a sub ECU 221, a sub ECU 222, a sub ECU 230, a sub ECU 240, a sub ECU 231, a sub ECU 232, a sub ECU 241, and a sub ECU 242. and an ADAS-ECU 290. The ECU is an electronic control unit. Each ECU is realized by having an arithmetic processing unit such as a processor and a volatile and non-volatile storage medium, and operates by the operation of the arithmetic processing unit using information stored in the storage medium.

Both the main ECU 210 and the sub ECU 220 are connected to the first CAN 101 and the second CAN 102 and can communicate with each other through the first CAN 101 and the second CAN 102 . Both the main ECU 210 and the sub ECU 230 are connected to the first CAN 111 and the second CAN 112 and can communicate with each other through the first CAN 111 and the second CAN 112 . Both the main ECU 210 and the TCU 201 are connected to the first CAN 121 and the second CAN 122 and can communicate with each other through the first CAN 121 and the second CAN 122 . Both the main ECU 210 and the ADAS-ECU 290 are connected to the first CAN 131 and the second CAN 132 and are connected to the ADAS-ECU 290 through the first CAN 131 and the second CAN 132 . The first CAN 101, the second CAN 102, the first CAN 111, the second CAN 112, the first CAN 121, the second CAN 122, the first CAN 131, and the second CAN 132 are CANs (Controller Area Networks). CAN is an example of a communication network.

The main ECU 210 controls the sub ECU 220, the sub ECU 221, the sub ECU 222, the sub ECU 230, the sub ECU 240, the sub ECU 231, the sub ECU 232, the sub ECU 241, the sub ECU 242, the TCU 201, the main ECU 210, the sub ECU 220, and the ADAS-ECU 290. TCU 201 is a telematics control unit. The TCU 201 is mainly responsible for mobile communications. For example, the TCU 201 transmits and receives data to and from an external server under the control of the main ECU 210 . The data received by the TCU 201 can be transmitted to the sub ECU or the ADAS-ECU 290 through the main ECU 210 . Data transmitted to the sub-ECU and the ADAS-ECU 290 can be transmitted to the TCU 201 through the main ECU 210. The ADAS-ECU 290 controls ADAS (Advanced Driver Assistance System).

Sub ECU220 controls sub ECU221 and sub ECU222 connected through CAN103. Sub ECU 230 controls sub ECU 231 and sub ECU 232 connected through CAN 113 . Sub ECU 240 controls sub ECU 241 and sub ECU 242 connected through CAN 114 . The sub-ECU 221 , the sub-ECU 222 , the sub-ECU 231 , the sub-ECU 232 , the sub-ECU 241 and the sub-ECU 242 are ECUs that directly control controlled devices provided in the vehicle 20 . Devices to be controlled are, for example, an engine, a fuel injection device, a motor, a battery, a locking device, and the like.

In this embodiment, the communication system 200 includes a communication device 203 having a TCU 201 and an antenna 202, a main ECU 210, a sub ECU 220, a sub ECU 221, a sub ECU 222, a sub ECU 230, a sub ECU 240, a sub ECU 231, a sub ECU 232, and a sub ECU 241. , and the sub-ECU including the sub-ECU 242, and the ADAS-ECU 290, the system configuration of the communication system 200 is not limited to the example of this embodiment.

In the present embodiment, examples of the "communication device" are the main ECU 210, the sub-ECU 220, the sub-ECU 230 and the sub-ECU 240, examples of the "first CAN communication network" are the first CAN 101 and the first CAN 111, and a "second CAN communication network". A case where the second CAN 102 and the second CAN 112 are taken as an example will be described. However, the ADAS-ECU 290 and the TCU 201 are examples of the "communication device", the first CAN 121 and the first CAN 131 are examples of the "first CAN communication network", and the second CAN 122 and the second CAN 132 are examples of the "first CAN communication network". good. Further, it is also possible to adopt a form in which the above-described controlled device or an ECU such as the sub ECU 221 that directly controls the controlled device is a “communication device”.

First, an outline of communication control between the main ECU 210 and the sub ECU 220 will be described. The main ECU 210 and the sub ECU 220 are examples of communication devices connected together to the first CAN 101 and the second CAN 102 . Main ECU 210 transmits first data to sub ECU 220 through first CAN 101 and receives second data transmitted from sub ECU 220 through second CAN 102 . The main ECU 210 switches the CAN communication network used for transmission of the first data from the first CAN 101 to the second CAN 102 when the first CAN 101 does not receive a positive response to the transmission of the first data through the first CAN 101 .

The main ECU 210 does not need to transmit data through the second CAN 102 and receive data through the first CAN 101, except when an acknowledgment from the sub ECU 220 cannot be received.

The first data may be data of a first type. First CAN 101 may be a CAN communication network used by main ECU 210 to transmit the first type of data. The second CAN 102 may be a CAN communication network used by the main ECU 210 to transmit data of a second type different from the first type. Main ECU 210 may transmit the second type of third data to sub ECU 220 through second CAN 102 . The CAN communication network used for transmitting the second type of data may be switched from the second CAN 102 to the first CAN 101 when an acknowledgment of the transmission of the third data over the second CAN 102 is not obtained through the second CAN 102 .

Main ECU 210 may determine whether the data is the first type data or the second type data based on the value of the ID field of the data frame transmitted through first CAN 101 or second CAN 102 .

First CAN 101 is a CAN communication network used by main ECU 210 to transmit data in the first period, and may be a CAN communication network used by main ECU 210 to receive data in the second period. Second CAN 102 is a CAN communication network used by main ECU 210 to receive data in the first period, and may be a CAN communication network used by main ECU 210 to transmit data in the second period. The main ECU 210 transmits the first data to the sub ECU 220 via the first CAN 101 in the first period. The CAN communication network used for transmission may be switched from the first CAN 101 to the second CAN 102 . In the second period, main ECU 210 transmits the fifth data to sub ECU 220 via second CAN 102, and if a positive response to the transmission of the fourth data via second CAN 102 is not obtained via second CAN 102, main ECU 210 transmits the fifth data. The CAN communication network used for transmission may be switched from the second CAN 102 to the first CAN 101 .

The main ECU 210 and the sub ECU 220 may be the only communication devices connected to the first CAN 101 and the second CAN 102 .

The first data may be data of the first type, and the first CAN 101 may be a CAN communication network used by the main ECU 210 to transmit the data of the first type. The second CAN 102 may be a CAN communication network used by the main ECU 210 to transmit data of a second type different from the first type. Main ECU 210 may transmit the second type of third data to sub ECU 220 through second CAN 102 . The CAN communication network used for transmitting the second type of data may be switched from the second CAN 102 to the first CAN 101 when an acknowledgment of the transmission of the third data over the second CAN 102 is not obtained through the second CAN 102 .

The main ECU 210 does not need to transmit data through the second CAN 102 and receive data through the first CAN 101, except when an acknowledgment from the sub ECU 220 cannot be received.

Next, an outline of communication control between the main ECU 210 and the sub ECUs 220 and 230 will be described. Main ECU 210 transmits first data to sub-ECU 230 and sub-ECU 240 through first CAN 111 and receives second data transmitted from sub-ECU 230 or sub-ECU 240 through second CAN 112 . The main ECU 210 switches the CAN communication network used for transmission of the first data from the first CAN 111 to the second CAN 112 when the first CAN 111 does not receive a positive response to the transmission of the first data through the first CAN 101 .

The sub ECU 240 is connected to both the first CAN 111 and the second CAN 112 .
Main ECU 210 transmits first data to sub ECU 230 and sub ECU 240 through first CAN 111 . Main ECU 210 receives the fourth data transmitted from sub ECU 240 through second CAN 112 .

First CAN 111 is a CAN communication network used by main ECU 210 to transmit data in the first period, and may be a CAN communication network used by main ECU 210 to receive data in the second period. Second CAN 112 is a CAN communication network used by main ECU 210 to receive data in the first period, and may be a CAN communication network used by main ECU 210 to transmit data in the second period. Main ECU 210 transmits the first data to sub ECU 230 and sub ECU 240 via first CAN 111 in the first period, and if a positive response to the transmission of the first data via first CAN 111 is not obtained via first CAN 111, main ECU 210 The CAN communication network used for transmitting one data may be switched from the first CAN 111 to the second CAN 112 . In the second period, main ECU 210 transmits fifth data to sub ECU 230 and sub ECU 240 via second CAN 112, and if a positive response to the transmission of the fifth data via second CAN 112 is not obtained via second CAN 112, main ECU 210 5 The CAN communication network used for data transmission may be switched from the second CAN 112 to the first CAN 111 .

The first CAN 111 is a CAN communication network used by the main ECU 210 to transmit data, and may be a CAN communication network used by the sub ECU 230 and the sub ECU 240 to receive data transmitted from the main ECU 210 through the first CAN 111. Second CAN 112 may be a CAN communication network used by sub-ECU 230 and sub-ECU 240 to transmit data, and may be a CAN communication network used by main ECU 210 by temporally switching between data transmission and data reception. . When the main ECU 210 transmits the sixth data to the sub ECU 230 and the sub ECU 240 via the second CAN 112 and does not obtain a positive response to the transmission of the sixth data via the second CAN 112 via the second CAN 112, the main ECU 210 transmits the sixth data. The CAN communication network used for transmission may be switched from the second CAN 112 to the first CAN 111 .

The first data may be data of the first type, and the first CAN 111 may be a communication network used by the main ECU 210 to transmit the data of the first type. Second CAN 112 may be a CAN communication network used by main ECU 210 to transmit a second type of data different from the first type. Main ECU 210 may transmit the second type of third data to sub ECU 230 and sub ECU 240 through second CAN 112 . The CAN communication network used for transmitting the second type of data may be switched from the second CAN 112 to the first CAN 111 when an acknowledgment of the transmission of the third data over the second CAN 112 is not obtained through the second CAN 112 .

Main ECU 210 can communicate with other communication devices connected by other communication networks. Neither sub ECU 230 nor sub ECU 240 is connected to another communication network. The sub ECU 230 and the sub ECU 240 are communication devices that communicate with other communication devices via the main ECU 210 . "Other communication devices" for sub ECU 230 and sub ECU 240 may be, for example, TCU 201, ADAS-ECU 290, sub ECU 220, sub ECU 221, sub ECU 222, and the like. Thus, the main ECU 210 is an ECU that relays communication between multiple communication devices.

FIG. 2 shows an example of a data frame format defined by the CAN protocol. FIG. 2 shows a data frame in a standard format (standard ID format) defined by the CAN protocol. The data frame includes SOF (Start Of Frame), ID field, RTR (Remote Transmission Request), IDE (Identifier Extension), control field, data field, CRC (Cyclic Redundancy Check) sequence, CRC delimiter "DEL", ACK (Acknowledgment ) slot, ACK delimiter “DEL”, and EOF (End Of Frame) fields.

The SOF is composed of a 1-bit dominant. When the bus is in an idle state, it is recessive, and the start of frame transmission is notified by changing it to dominant by SOF.

The ID field consists of 11 bits. The ID field is a field for storing an ID, which is a value indicating the type of data to be transmitted. When a plurality of ECUs start transmission at the same time, a frame having a small ID value is given a high priority and is transmitted because communication is arbitrated in the ID field.

RTR is a value for identifying whether it is a data frame or a remote frame, and is composed of dominant 1 bit in a data frame.

The control field is composed of a 1-bit long IDE (Identifier Extension), a reserved bit r, and a 4-bit long Data Length Code (DLC). Both IDE and reserved bit r are dominant. DLC indicates the number of bytes of data transmitted in the data field following the control field. The setting range of DLC is 0 or more and 8 or less. Therefore, the data transmitted in the data field is 0 to 8 bytes (64 bits) in units of 1 byte.

The data field is a value indicating the content of data to be transmitted, which consists of a maximum of 64 bits. The data field can be adjusted in length every 8 bits. The specification of the data transmitted in the data field is not specified in the CAN protocol. Specifications for data transmitted in the data field are defined in the communication system 200 . In other words, the specifications are determined by the model and manufacturer of the vehicle 20 .

A CRC sequence consists of 15 bits. A CRC sequence is calculated from the transmission values of the SOF, ID field, control field and data field. The CRC delimiter is a delimiter representing the end of the CRC sequence composed of 1-bit recessive.

The ACK slot consists of 1 bit. The ECU on the transmission side performs transmission with a recessive ACK slot. If the ECU on the receiving side can normally receive up to the CRC delimiter, it transmits the ACK slot as dominant. Since dominant is given priority over recessive, if the ACK slot is dominant, the ECU on the transmission side can confirm that any other ECU has successfully received. The signal in the ACK slot is an example of an "acknowledgment."

The ACK delimiter is a delimiter representing the end of ACK composed of 1-bit recessive. EOF is composed of 7-bit recessive and indicates the end of the data frame. EOF is followed by ITM (Intermission), which is a 3-bit recessive, and the bus becomes idle after the end of ITM.

FIG. 3 is a diagram for explaining communication control between main ECU 210 and sub ECU 220 in one embodiment. In the present embodiment, first CAN 101 is a CAN exclusively used for main ECU 210 to transmit data when first CAN 101 is not malfunctioning. In other words, first CAN 101 is a CAN exclusively used by sub ECU 220 to receive data when first CAN 101 is not malfunctioning. Second CAN 102 is a CAN exclusively used by sub ECU 220 to transmit data when second CAN 102 is normal. That is, second CAN 102 is a CAN exclusively used when main ECU 210 receives data when second CAN 102 does not have an abnormality.

Therefore, main ECU 210 does not transmit data through second CAN 102 when first CAN 101 is normal. In addition, sub-ECU 220 does not transmit data through first CAN 101 when second CAN 102 does not have an abnormality. Accordingly, communication arbitration is not performed between the main ECU 210 and the sub ECU 220 unless there is an abnormality in either the first CAN 101 or the second CAN 102 . Therefore, the transmission of the data frame is not kept waiting for a long time due to the communication arbitration. While one CAN is half-duplex communication of CSMA/CA, according to this embodiment, communication can be performed in the form of full-duplex communication.

If the ACK slot is dominant in the data frame transmitted from main ECU 210 to first CAN 101, main ECU 210 determines that an acknowledgment has been obtained from sub ECU 220, and determines that first CAN 101 is not abnormal. On the other hand, if the ACK slot is recessive, it is determined that an acknowledgment could not be obtained from the sub ECU 220, and that the first CAN 101 is abnormal. When the ACK slot is recessive in the data frame that main ECU 210 has transmitted to first CAN 101 , main ECU 210 switches the CAN that main ECU 210 uses for data transmission from first CAN 101 to second CAN 102 . This allows main ECU 210 to continue transmitting data to sub ECU 220 .

Note that, similarly to main ECU 210, sub ECU 220 determines that an acknowledgment has been obtained from main ECU 210 if the ACK slot in the data frame that sub ECU 220 has transmitted to second CAN 102 is dominant, and that second CAN 102 has an abnormality. judge not. On the other hand, if the ACK slot is recessive, it is determined that an acknowledgment could not be obtained from main ECU 210 and that second CAN 102 is abnormal. When the ACK slot is recessive in the data frame transmitted by sub ECU 220 to second CAN 102 , sub ECU 220 switches the CAN used by sub ECU 220 for data transmission from second CAN 102 to first CAN 101 . Thereby, sub ECU 220 can continue to transmit data to main ECU 210 .

FIG. 4 is a diagram for explaining communication control between the main ECU 210 and the sub ECU 230 and the sub ECU 230 in one embodiment. In this embodiment, the first CAN 111 is a CAN exclusively used by the main ECU 210 to transmit data when there is no abnormality in the first CAN 111 . In other words, first CAN 111 is a CAN exclusively used by sub-ECU 230 and sub-ECU 240 to receive data when first CAN 111 is not malfunctioning.

Second CAN 112 is a CAN exclusively used for data transmission by sub ECU 230 and sub ECU 240 when second CAN 112 is normal. In other words, second CAN 112 is a CAN that is exclusively used when main ECU 210 receives data transmitted from sub ECU 230 and sub ECU 240 when second CAN 112 is normal. Second CAN 112 is a CAN exclusively used when sub ECU 230 receives data transmitted from sub ECU 240 . Second CAN 112 is a CAN used when sub ECU 240 receives data transmitted from sub ECU 230 .

As a result, the main ECU 210 does not transmit data through the second CAN 112 when the first CAN 111 is normal. In addition, sub ECU 230 and sub ECU 240 do not transmit data through first CAN 111 when there is no abnormality in second CAN 112 . Accordingly, communication arbitration is not performed between the main ECU 210 and the sub ECU 230 and the sub ECU 230 unless there is an abnormality in either the first CAN 111 or the second CAN 112 . Therefore, the transmission of the data frame is not kept waiting for a long time due to the communication arbitration. Further, when there is no abnormality in the second CAN 112, since the first CAN 111 is exclusively used for data transmission by the main ECU 210, instructions can be promptly transmitted from the main ECU 210 to the sub ECU 230 or the sub ECU 240.

If the ACK slot is dominant in the data frame transmitted by main ECU 210 to first CAN 111, main ECU 210 determines that an acknowledgment has been received from at least one of sub-ECU 230 and sub-ECU 240, and determines that first CAN 111 is not abnormal. to decide. On the other hand, if the ACK slot is recessive, it is determined that an acknowledgment has not been obtained from either sub ECU 230 or sub ECU 240, and that first CAN 111 is abnormal. When the ACK slot is recessive in the data frame transmitted by main ECU 210 to first CAN 111 , main ECU 210 switches the CAN used by main ECU 210 for data transmission from first CAN 111 to second CAN 112 . Thereby, the main ECU 210 can continue to transmit data to the sub ECU 230 and the sub ECU 240 .

Note that, similarly to the main ECU 210, if the ACK slot in the data frame that the sub ECU 230 has transmitted to the second CAN 112 is dominant, the sub ECU 230 determines that an acknowledgment has been obtained from the main ECU 210 or the sub ECU 240, and the second CAN 112 is abnormal. is not occurring. On the other hand, if the ACK slot is recessive, it is determined that an acknowledgment has not been obtained from either main ECU 210 or sub ECU 240, and that second CAN 112 is abnormal. When the ACK slot is recessive in the data frame that sub ECU 230 has transmitted to second CAN 112 , sub ECU 230 switches the CAN that sub ECU 230 uses for data transmission from second CAN 112 to first CAN 111 . Thereby, sub ECU 230 can continue to transmit data to main ECU 210 or sub ECU 240 .

Further, similarly to sub ECU 230, if the ACK slot in the data frame transmitted by sub ECU 240 to second CAN 112 is dominant, sub ECU 240 determines that an acknowledgment has been obtained from main ECU 210 or sub ECU 230, and determines that second CAN 112 is abnormal. is not occurring. On the other hand, if the ACK slot is recessive, it is determined that an acknowledgment could not be obtained from either main ECU 210 or sub ECU 230, and that second CAN 112 is abnormal. When the ACK slot is recessive in the data frame transmitted by sub ECU 240 to second CAN 112 , sub ECU 240 switches the CAN used by sub ECU 240 for data transmission from second CAN 112 to first CAN 111 . Thereby, sub ECU 240 can continue to transmit data to main ECU 210 or sub ECU 230 .

FIG. 5 shows an example of a flowchart showing a procedure related to the communication control method executed by the main ECU 210. As shown in FIG. Here, the communication control method of the main ECU 210 in the aspect described with reference to FIG. 3 will be taken up and described. The processing of this flowchart is started when main ECU 210 transmits data to sub ECU 220 .

In S502, main ECU 210 determines whether first CAN 101 is abnormal. If it is determined that the first CAN 101 is not abnormal, the main ECU 210 transmits data through the first CAN 101 (S504), and determines whether or not a confirmation response has been received from the sub ECU 220 (S506). In S506, main ECU 210 determines that an acknowledgment has been obtained if the ACK slot is dominant, and determines that an acknowledgment has not been obtained if the ACK slot is recessive. If it is determined in S506 that an acknowledgment has been obtained, the processing of this flowchart ends.

If it is determined in S506 that an acknowledgment has not been obtained, in S504 the main ECU 210 determines that the first CAN 101 is abnormal. For example, main ECU 210 stores determination information indicating that first CAN 101 is abnormal in an internal memory provided therein. After performing the process of S504, the process returns to S502. In S502, main ECU 210 determines that an abnormality has occurred in first CAN 101 when information indicating that an abnormality has occurred in first CAN 101 is stored in the internal memory, and the abnormality has occurred in first CAN 101. If the information indicating that the first CAN 101 is not stored in the internal memory, it is determined that the first CAN 101 is not abnormal. If it is determined in S502 that the first CAN 101 is abnormal, the main ECU 210 transmits the data through the second CAN 102 and terminates the processing of this flowchart.

The process shown in FIG. 5 can be applied to the process of switching the CAN used by main ECU 210 for data transmission in the aspect described with reference to FIG. In addition, the processing similar to the processing shown in FIG. It can be applied to the process of switching the CAN used for data transmission, the process of switching the CAN used for data transmission by the sub ECU 240 in the aspect described with reference to FIG. 3, and the like.

FIG. 6 is a diagram for explaining a first modification of communication control between main ECU 210 and sub ECU 220. In FIG. In this modification, the first CAN 101 is used by the main ECU 210 to transmit a type of data frame in which a value other than "1" is set in the ID field of the data frame when there is no abnormality in the first CAN 101. Second CAN 102 is defined as a CAN used by main ECU 210 to transmit a data frame of the type in which "1" is set in the ID field of the data frame. If there is a high probability that the transmission timing of the data frame with ID "1" by the main ECU 210 will not conflict with the transmission timing of the data frame by the sub ECU 220, communication arbitration will occur even if the data frame with ID "1" is transmitted through the second CAN 102. less likely to. By adopting this modification, when the amount of data transmitted from main ECU 210 to sub-ECU 220 is large, the communication load can be distributed between first CAN 101 and second CAN 102 .

In this modification, main ECU 210 determines that an acknowledgment has been obtained from sub ECU 220 if the ACK slot of a data frame other than ID "1" transmitted by main ECU 210 to first CAN 101 is dominant, and the ACK slot is recessive. If so, it is determined that an acknowledgment could not be obtained from the sub ECU 220 . When the ACK slot is recessive in the data frame transmitted by the main ECU 210 to the first CAN 101, the main ECU 210 switches the CAN used by the main ECU 210 for transmitting data frames other than ID "1" from the first CAN 101 to the second CAN 102. This allows main ECU 210 to continue transmitting data to sub ECU 220 .

FIG. 7 is a diagram for explaining a first modification of communication control between main ECU 210 and sub-ECU 230 and sub-ECU 240. In FIG. In this modification, the first CAN 111 is used by the main ECU 210 to transmit a type of data frame in which a value other than "1" is set in the ID field of the data frame when there is no abnormality in the first CAN 111. Second CAN 112 is defined as a CAN used by main ECU 210 to transmit a data frame of a type in which "1" is set in the ID field of the data frame.

In this modification, main ECU 210 determines that an acknowledgment has been obtained from sub ECU 230 or sub ECU 240 if the ACK slot in a data frame other than ID "1" transmitted by main ECU 210 to first CAN 111 is dominant, and ACK is received. If the slot is recessive, it is determined that confirmation responses have not been obtained from either sub ECU 230 or sub ECU 240 . When the ACK slot is recessive in the data frame transmitted by the main ECU 210 to the first CAN 111, the main ECU 210 switches the CAN used by the main ECU 210 for transmitting data frames other than ID "1" from the first CAN 111 to the second CAN 112. Thereby, the main ECU 210 can continue to transmit data to the sub ECU 230 and the sub ECU 240 .

FIG. 8 is a diagram for explaining a second modification of communication control between main ECU 210 and sub-ECUs 230 and 240. In FIG. FIG. 8 is a diagram showing whether each of the first CAN 111 and the second CAN 112 is used by the main ECU 210 for data transmission or data reception. "Transmission" in FIG. 8 indicates that main ECU 210 is used for data transmission, and "reception" indicates that main ECU 210 is used for data reception.

In this modification, when there is no abnormality in the first CAN 111 and the second CAN 112, the first CAN 111 is used for data transmission by the main ECU 210, and the sub ECU 230 and the sub ECU 240 are used as CANs for data reception. Second CAN 112 is used as a CAN for sub-ECU 230 and sub-ECU 240 to transmit data, and main ECU 210 switches between data transmission and data reception to use second CAN 112 .

For example, during the period from time t1 to time t2 and the period from time t3 to time t4, the main ECU 210 uses the second CAN 112 only for data reception. During the period from time t2 to time t3, main ECU 210 can use second CAN 112 for data transmission. In this way, main ECU 210 uses second CAN 112 by temporally switching between data transmission and data reception.

If the ACK slot in the data frame transmitted by main ECU 210 to second CAN 112 is dominant during the period from time t2 to time t3, main ECU 210 determines that an acknowledgment has been obtained from sub ECU 230 or sub ECU 240. It is determined that the 2CAN 112 is not abnormal. On the other hand, if the ACK slot is recessive, it is determined that an acknowledgment has not been obtained from either sub-ECU 230 or sub-ECU 240, and that second CAN 112 is abnormal. When the ACK slot is recessive in the data frame that main ECU 210 has transmitted to second CAN 112, main ECU 210 switches from second CAN 112 to first CAN 111 to transmit data. This allows main ECU 210 to continue transmitting data to sub ECU 230 or sub ECU 240 .

FIG. 9 is a diagram for explaining a second modification of communication control between main ECU 210 and sub ECU 220. In FIG. FIG. 9 is a diagram showing whether each of first CAN 101 and second CAN 102 is used by main ECU 210 for data transmission or data reception. "Transmission" in FIG. 9 indicates that main ECU 210 is used for data transmission, and "reception" indicates that main ECU 210 is used for data reception.

In this modification, the main ECU 210 temporally switches the CAN used for data transmission when there is no abnormality in the first CAN 101 and the second CAN 102 . For example, during the period from time t1 to time t2, the first CAN 101 is assigned as the CAN used by the main ECU 210 for data transmission, and the second CAN 102 is assigned as the CAN used by the sub ECU 220 for data transmission. During the period from time t2 to time t3, the second CAN 102 is assigned as the CAN used by the main ECU 210 for data transmission, and the first CAN 101 is assigned as the CAN used by the sub ECU 220 for data transmission. During the period from time t3 to time t4, the first CAN 101 is assigned as the CAN used by the main ECU 210 for data transmission, and the second CAN 102 is assigned as the CAN used by the sub ECU 220 for data transmission. In this way, main ECU 210 temporally switches the CAN used for transmission.

If the ACK slot in the data frame transmitted by main ECU 210 to second CAN 102 is dominant during the period from time t2 to time t3, main ECU 210 determines that an acknowledgment has been received from sub ECU 220, and second CAN 102 is abnormal. is not occurring. On the other hand, if the ACK slot is recessive, it is determined that an acknowledgment could not be obtained from sub ECU 220 and that second CAN 102 is abnormal. When the ACK slot is recessive in the data frame that main ECU 210 has transmitted to second CAN 102 , main ECU 210 switches the CAN that main ECU 210 uses for data transmission from second CAN 102 to first CAN 101 . This allows main ECU 210 to continue transmitting data to sub ECU 220 .

The CAN switching control in the second modification described with reference to FIG. 9 can also be applied to CAN switching control in communication between the main ECU 210 and the sub ECUs 230 and 240 . Further, by combining the first modified example and the second modified example as described with reference to FIG. 6 and FIG. can also be applied.

As described above, according to the communication system 200 according to the present embodiment, the CANs connecting the ECUs are multiplexed, and the CAN used by each ECU for data transmission and the CAN used for data reception are separated. , the probability of occurrence of communication arbitration can be reduced. When an abnormality occurs in one CAN, data transmission can be continued by switching the CAN used for data transmission to the other CAN.

The vehicle 20 is a vehicle as an example of transportation equipment. The vehicle may be an automobile with an internal combustion engine, an electric vehicle, a fuel cell vehicle (FCV), or the like. Automobiles include buses, trucks, two-wheeled vehicles, and the like. The vehicle may be a straddle-type vehicle or the like, or may be a motorcycle. In addition to vehicles, transportation equipment includes equipment such as aircraft including unmanned aircraft, ships, and the like. A transport device may be any device that transports people or goods. A transportation device is an example of a mobile object. The mobile object is not limited to transportation equipment, and may be any movable equipment.

FIG. 10 illustrates an example computer 2000 in which embodiments of the invention may be implemented in whole or in part. The program installed in the computer 2000 causes the computer 2000 to function as a system such as a communication system according to an embodiment, a communication device, or each part of the device, to execute operations associated with the device or each part of the device, and /or a process according to an embodiment or a step of the process may be performed. Such programs may be executed by CPU 2012 to cause computer 2000 to perform specific operations associated with some or all of the process steps and block diagram blocks described herein.

A computer 2000 according to this embodiment includes a CPU 2012 and a RAM 2014 , which are interconnected by a host controller 2010 . Computer 2000 also includes ROM 2026 , flash memory 2024 , communication interface 2022 and input/output chip 2040 . ROM 2026 , flash memory 2024 , communication interface 2022 and input/output chip 2040 are connected to host controller 2010 via input/output controller 2020 .

The CPU 2012 operates according to programs stored in the ROM 2026 and RAM 2014, thereby controlling each unit.

Communication interface 2022 communicates with other electronic devices over a network. Flash memory 2024 stores programs and data used by CPU 2012 in computer 2000 . ROM 2026 stores programs such as boot programs that are executed by computer 2000 upon activation and/or programs that depend on the hardware of computer 2000 . Input/output chip 2040 also supports various input/output units such as keyboards, mice and monitors as input/output units such as serial ports, parallel ports, keyboard ports, mouse ports, monitor ports, USB ports, HDMI ports, etc. It may be connected to the input/output controller 2020 via an output port.

The program is provided via a computer-readable storage medium such as a CD-ROM, DVD-ROM, or memory card or via a network. RAM 2014, ROM 2026, or flash memory 2024 are examples of computer-readable storage media. Programs are installed in flash memory 2024 , RAM 2014 , or ROM 2026 and executed by CPU 2012 . The information processing described within these programs is read by computer 2000 to provide coordination between the programs and the various types of hardware resources described above. An apparatus or method may be configured by implementing information operations or processing according to the use of computer 2000 .

For example, when communication is executed between the computer 2000 and an external device, the CPU 2012 executes a communication program loaded in the RAM 2014 and sends communication processing to the communication interface 2022 based on the processing described in the communication program. you can command. Under the control of the CPU 2012, the communication interface 2022 reads transmission data stored in a transmission buffer processing area provided in a recording medium such as the RAM 2014 and the flash memory 2024, transmits the read transmission data to the network, and receives the transmission data from the network. The received data is written in a receive buffer processing area or the like provided on the recording medium.

The CPU 2012 also causes the RAM 2014 to read all or necessary portions of a file or database stored in a recording medium such as the flash memory 2024, and performs various types of processing on the data on the RAM 2014. good. CPU 2012 then writes back the processed data to the recording medium.

Various types of information such as various types of programs, data, tables, and databases may be stored on the recording medium and subjected to information processing. CPU 2012 performs various types of operations, information processing, conditional judgment, conditional branching, unconditional branching, information retrieval/ Various types of processing may be performed, including permutations, etc., and the results written back to RAM 2014 . Also, the CPU 2012 may search for information in a file in a recording medium, a database, or the like. For example, if multiple entries each having an attribute value of a first attribute associated with an attribute value of a second attribute are stored in the recording medium, the CPU 2012 determines which attribute value of the first attribute is specified. search the plurality of entries for an entry that matches the condition, read the attribute value of the second attribute stored in the entry, and thereby determine the first attribute that satisfies the predetermined condition. An attribute value of the associated second attribute may be obtained.

The programs or software modules described above may be stored in a computer-readable storage medium on or near computer 2000 . A storage medium such as a hard disk or RAM provided in a server system connected to a dedicated communication network or the Internet can be used as a computer-readable storage medium. A program stored in a computer-readable storage medium may be provided to computer 2000 via a network.

A program installed in the computer 2000 and causing the computer 2000 to function as the communication system 200 may act on the CPU 2012 and the like to cause the computer 2000 to function as each part of the communication system 200 . The information processing described in these programs is read by the computer 2000 and functions as each part of each ECU, which is concrete means in which the software and various hardware resources described above cooperate. By implementing calculation or processing of information according to the purpose of use of the computer 2000 in this embodiment by these specific means, a unique ECU corresponding to the purpose of use is constructed.

Various embodiments have been described with reference to block diagrams and the like. Each block in the block diagram may represent (1) a stage of a process in which an operation is performed or (2) a piece of equipment responsible for performing the operation. Certain steps and portions may be implemented by dedicated circuitry, programmable circuitry provided with computer readable instructions stored on a computer readable storage medium, and/or processor provided with computer readable instructions stored on a computer readable storage medium. may be implemented. Dedicated circuitry may include digital and/or analog hardware circuitry and may include integrated circuits (ICs) and/or discrete circuitry. Programmable circuits include logic AND, logic OR, logic XOR, logic NAND, logic NOR, and other logic operations, memory elements such as flip-flops, registers, field programmable gate arrays (FPGAs), programmable logic arrays (PLAs), etc. and the like.

A computer-readable storage medium may comprise any tangible device capable of storing instructions to be executed by a suitable device such that a computer-readable storage medium having instructions stored thereon may be represented by a process procedure or block diagram. constitutes at least part of an article of manufacture that includes instructions executable to bring about means for performing the operations specified in . Examples of computer-readable storage media may include electronic storage media, magnetic storage media, optical storage media, electromagnetic storage media, semiconductor storage media, and the like. More specific examples of computer readable storage media include floppy disks, diskettes, hard disks, random access memory (RAM), read only memory (ROM), erasable programmable read only memory (EPROM or flash memory) , electrically erasable programmable read only memory (EEPROM), static random access memory (SRAM), compact disc read only memory (CD-ROM), digital versatile disc (DVD), Blu-ray (RTM) disc, memory stick, An integrated circuit card or the like may be included.

The computer readable instructions may be assembler instructions, Instruction Set Architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state configuration data, or instructions such as Smalltalk, JAVA, C++, etc. any source or object code written in any combination of one or more programming languages, including object-oriented programming languages, and conventional procedural programming languages such as the "C" programming language or similar programming languages; may include

Computer readable instructions may be transmitted to a processor or programmable circuitry of a general purpose computer, special purpose computer, or other programmable data processing apparatus, either locally or over a wide area network (WAN), such as a local area network (LAN), the Internet, or the like. ) and may be executed to provide means for performing the operations specified in the process steps or block diagrams described. Examples of processors include computer processors, processing units, microprocessors, digital signal processors, controllers, microcontrollers, and the like.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is obvious to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the description of the scope of claims that forms with such modifications or improvements can also be included in the technical scope of the present invention.

The execution order of each process such as actions, procedures, steps, and stages in the devices, systems, programs, and methods shown in the claims, the specification, and the drawings is etc., and it should be noted that they can be implemented in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the specification, and the drawings, even if the description is made using "first," "next," etc. for convenience, it means that it is essential to carry out in this order. not a thing

20 vehicle 200 communication system 210 main ECU
220, 221, 222 Sub ECU
230, 231, 232 Sub ECU
240, 241, 242 Sub ECU
101 1st CAN
102 2nd CAN
103, 113, 114 CAN
111 1st CAN
112 2nd CAN
121 1st CAN
122 2nd CAN
131 1st CAN
132 2nd CAN
201 TCUs
202 Antenna 203 Communication device 290 ADAS-ECU
2000 computer 2010 host controller 2012 CPU
2014 RAM
2020 input/output controller 2022 communication interface 2024 flash memory 2026 ROM
2040 input/output chip

Claims (17)

A first communication device and a second communication device connected together to a first CAN (Controller Area Network) communication network and a second CAN communication network;
The first communication device is
transmitting first data to the second communication device through the first CAN communication network, receiving second data transmitted from the second communication device through the second CAN communication network;
When a positive response to the transmission of the first data through the first CAN communication network is not obtained through the first CAN communication network, the CAN communication network used for transmitting the first data is selected from the first CAN communication network to the A communication system that switches to a second CAN communication network. The first communication device does not transmit data through the second CAN communication network and does not receive data through the first CAN communication network unless the acknowledgment from the second communication device cannot be received. A communication system according to claim 1. 2. The communication system according to claim 1, wherein communication devices connected to said first CAN communication network and said second CAN communication network are only said first communication device and said second communication device. The first data is data of a first type,
The first CAN communication network is a CAN communication network used by the first communication device to transmit the first type of data,
The second CAN communication network is a CAN communication network used by the first communication device to transmit data of a second type different from the first type,
The first communication device transmits the second type of third data to the second communication device through the second CAN communication network,
When a positive response to the transmission of the third data through the second CAN communication network is not obtained through the second CAN communication network, the CAN communication network used for transmitting the second type of data is selected from the second CAN communication network. to the first CAN communication network. The first communication device determines whether the data is the first type data or the second type data based on the value of the ID field of the data frame transmitted through the first CAN communication network or the second CAN communication network. 5. The communication system according to claim 4, wherein the determination of The first communication device does not transmit data through the second CAN communication network and does not receive data through the first CAN communication network unless the acknowledgment from the second communication device cannot be received. A communication system according to claim 3. further comprising a third communication device connected together to the first CAN communication network and the second CAN communication network;
The first communication device transmits the first data to the second communication device and the third communication device through the first CAN communication network,
The communication system according to claim 1, wherein said first communication device receives fourth data transmitted from said third communication device through said second CAN communication network. The first CAN communication network is a CAN communication network used by the first communication device to transmit data in a first period, and a CAN communication network used by the first communication device to receive data in a second period. and
The second CAN communication network is a CAN communication network used by the first communication device to receive data in the first period, and a CAN used by the first communication device to transmit data in the second period. is a communication network;
The first communication device, in the first period,
transmitting the first data to the second communication device and the third communication device through the first CAN communication network;
When a positive response to the transmission of the first data through the first CAN communication network is not obtained through the first CAN communication network, the CAN communication network used for transmitting the first data is selected from the first CAN communication network to the Switching to the second CAN communication network,
The first communication device, in the second period,
Transmitting fifth data to the second communication device and the third communication device through the second CAN communication network;
When a positive response to the transmission of the fifth data through the second CAN communication network is not obtained through the second CAN communication network, the CAN communication network used for transmitting the fifth data is selected from the second CAN communication network to the 8. The communication system of claim 7, wherein switching to the first CAN communication network. The first CAN communication network is a CAN communication network used by the first communication device to transmit data, and the second communication device and the third communication device transmit data from the first communication device through the first CAN communication network. A CAN communication network used to receive transmitted data,
The second CAN communication network is a CAN communication network used by the second communication device and the third communication device to transmit data, and the first communication device temporally synchronizes data transmission and data reception. It is a CAN communication network that is used by switching to
The first communication device, when transmitting the sixth data to the second communication device and the third communication device via the second CAN communication network, affirms the transmission of the sixth data via the second CAN communication network. 8. The communication system according to claim 7, wherein when a response is not obtained through the second CAN communication network, the CAN communication network used for transmitting the sixth data is switched from the second CAN communication network to the first CAN communication network. The first data is data of a first type,
The first CAN communication network is a CAN communication network used by the first communication device to transmit the first type of data,
The second CAN communication network is a CAN communication network used by the first communication device to transmit data of a second type different from the first type,
The first communication device transmits the second type of third data to the second communication device and the third communication device through the second CAN communication network,
When a positive response to the transmission of the third data through the second CAN communication network is not obtained through the second CAN communication network, the CAN communication network used for transmitting the second type of data is selected from the second CAN communication network. to the first CAN communication network. The first communication device is capable of communicating with a fourth communication device connected by a third communication network,
Neither the second communication device nor the third communication device is connected to a third communication network,
The communication according to any one of claims 7 to 10, wherein the second communication device and the third communication device are communication devices that communicate with the fourth communication device via the first communication device. system. The first data is data of a first type,
The first CAN communication network is a CAN communication network used by the first communication device to transmit the first type of data,
The second CAN communication network is a CAN communication network used by the first communication device to transmit data of a second type different from the first type,
The first communication device transmits the second type of third data to the second communication device through the second CAN communication network,
When a positive response to the transmission of the third data through the second CAN communication network is not obtained through the second CAN communication network, the CAN communication network used for transmitting the second type of data is selected from the second CAN communication network. to the first CAN communication network. The first CAN communication network is a CAN communication network used by the first communication device to transmit data in a first period, and a CAN communication network used by the first communication device to receive data in a second period. and
The second CAN communication network is a CAN communication network used by the first communication device to receive data in the first period, and a CAN used by the first communication device to transmit data in the second period. is a communication network;
The first communication device, in the first period,
transmitting the first data to the second communication device through the first CAN communication network;
When a positive response to the transmission of the first data through the first CAN communication network is not obtained through the first CAN communication network, the CAN communication network used for transmitting the first data is selected from the first CAN communication network to the Switching to the second CAN communication network,
The first communication device, in the second period,
transmitting fifth data to the second communication device through the second CAN communication network;
When a positive response to the transmission of the fifth data through the second CAN communication network is not obtained through the second CAN communication network, the CAN communication network used for transmitting the fifth data is selected from the second CAN communication network to the 3. The communication system of claim 2, wherein switching to the first CAN communication network. A mobile unit comprising a communication system according to any one of claims 1 to 13. A vehicle comprising a communication system according to any one of claims 1-13. A first communication device connected together to a first CAN communication network and a second CAN communication network transmits first data through the first CAN communication network to a second communication connected together to the first CAN communication network and the second CAN communication network. transmitting to the device;
the first communication device receiving second data transmitted from the second communication device through the second CAN communication network;
When a positive response to the transmission of the first data through the first CAN communication network is not obtained through the first CAN communication network, the CAN communication network used for transmitting the first data is selected from the first CAN communication network to the switching to a second CAN communication network;
A communication control method comprising: A program for causing a computer to function as a first communication device,
The first communication device is connected to the first CAN communication network and the second CAN communication network,
The program causes the computer to:
transmitting first data through the first CAN communication network to a second communication device connected to the first CAN communication network and the second CAN communication network, and transmitting second data transmitted from the second communication device to the second CAN communication network; received over the network,
When a positive response to the transmission of the first data through the first CAN communication network is not obtained through the first CAN communication network, the CAN communication network used for transmitting the first data is selected from the first CAN communication network to the A program to switch to the second CAN communication network.

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