JP2008302780A - On-vehicle communication system and on-vehicle communication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an on-vehicle communication system and an on-vehicle communication method capable of improving reliability of data to be distributed from a distributing device to each of on-vehicle devices by multiplexing connection between a plurality of on-vehicle devices and the distributing device connected to each of the on-vehicle devices so as to distribute the data transmitted from each of the on-vehicle devices to other on-vehicle device besides. <P>SOLUTION: On-vehicle devices 1a, 1b and 1c are respectively connected to a plurality of distribution devices 2a and 2b, and respectively transmit data to the distributing devices 2a and 2b. With this structure, even in the case wherein a trouble outbreaks in the distributing device 2a and, as a result, a data base 21a can not used, or even in the case wherein a trouble outbreaks in a vehicle-inside communication circuit 3a, data is distributed from the distributing device 2b to the on-vehicle devices 1a, 1b and 1c. Every time the on-vehicle devices 1a, 1b and 1c transmit the data, the on-vehicle devices 1a, 1b and 1c give the number to the data, modifying the number. The distributing devices 2a and 2b determine whether the data is the latest data or not by comparing the numbers, and stores only the latest data. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an in-vehicle communication system including a plurality of in-vehicle devices and a distribution device that is connected to each in-vehicle device and distributes data transmitted from each in-vehicle device to other in-vehicle devices. It is related with the vehicle-mounted communication system and vehicle-mounted communication method which can improve the reliability of the data distributed from a distribution apparatus to each vehicle-mounted apparatus.

  In recent years, with the increase in functions of in-vehicle devices using electronic control units (ECUs), the number and types of in-vehicle devices arranged in vehicles tend to increase.

  As the number of in-vehicle devices increases, the amount of data transmitted and received through the in-vehicle communication line to which the in-vehicle devices are connected also increases. An increase in the amount of data transmitted and received through the in-vehicle communication line causes data delay or loss due to collision (collision). A significant delay or loss of data lacks the reliability of the data content, and in some cases becomes fatal to a driving assistance function such as brake control by an in-vehicle device.

  Therefore, a configuration in which the in-vehicle devices are divided into a plurality of groups and the in-vehicle devices are connected to different in-vehicle communication lines for each group is common. In addition, in order to efficiently use in-vehicle communication lines against the increase in in-vehicle devices, there is a configuration in which groups of in-vehicle devices are classified according to the type of data transmitted and received and connected to in-vehicle communication lines with different communication speeds for each group. is there. In these configurations, different in-vehicle communication lines are connected by a gateway device that controls transmission and reception of data.

Patent Document 1 discloses a configuration in which in-vehicle devices are divided into a plurality of groups and connected to communication lines for each group, and in-vehicle communication lines are further connected by a gateway device, and priority for identifying priorities for data to be transmitted and received When the gateway device transmits / receives data between different in-vehicle communication lines, the priority is determined from the received data priority information and data with higher priority is transmitted preferentially. A technique is disclosed in which transmission of data with high priority is not greatly delayed even when the communication load increases.
JP 2005-159568 A

  However, when the in-vehicle devices are divided into a plurality of groups and each group is connected via a gateway device, each time data is transmitted from one group of in-vehicle devices to another group of in-vehicle devices, If data is transmitted to the in-vehicle device, the communication load between the in-vehicle devices cannot be reduced.

  In addition, when the in-vehicle devices are divided into a plurality of groups and each group is connected via a gateway device, the content of data updated by the in-vehicle devices in one group is updated via the gateway device. Until the data is transmitted to another group of in-vehicle devices, there is a time in which the data content does not match between one group and the other group. Furthermore, when a plurality of groups are connected in series to the gateway device, there is a possibility that a time difference will occur in steps in the data contents between one group and another group. In this case, the reliability of data in the in-vehicle communication system is not ensured.

  The present invention has been made in view of such circumstances, and has a database that stores data transmitted from a plurality of in-vehicle devices, and includes a distribution device that distributes the data to each in-vehicle device, thereby centralizing data. Management, to reduce the communication load and ensure the identity of the content of data distributed to each in-vehicle device, and to connect each in-vehicle device to each distribution device, thereby connecting each in-vehicle device and the database. Provided an in-vehicle communication system and an in-vehicle communication method capable of preventing a problem in processing of the entire in-vehicle communication system and improving its reliability by multiplexing connection relations when the distribution device is in trouble The purpose is to do.

  Another object of the present invention is to multiplex the connection relationship between each in-vehicle device and a database by connecting each in-vehicle device to a plurality of distribution devices. An in-vehicle communication system and an in-vehicle communication method capable of improving the reliability of data by assigning a number that can identify whether or not it is data and always updating the database with only the latest information in the distribution device Is to provide.

  The in-vehicle communication system according to the first invention includes a plurality of in-vehicle devices that transmit and receive data, means for receiving data from each in-vehicle device and storing it in a database, and storing the stored data in each in-vehicle device. An in-vehicle communication system comprising a plurality of distribution devices including means for distributing data to a plurality of distribution devices, wherein some or all of the in-vehicle devices are connected to the plurality of distribution devices, respectively, and the same data is sent to each distribution device. A means for transmitting is provided.

  In the in-vehicle communication system according to the second aspect of the invention, each of the distribution devices transmits means stored in the database to other distribution devices, and means stores the data transmitted from the other distribution devices in the database. It is characterized by providing.

  An in-vehicle communication system according to a third aspect of the present invention includes means for assigning a number to data and means for increasing (or decreasing) the number when each in-vehicle device transmits data. Alternatively, when data is received from another distribution device, a determination unit that determines whether the number of data received together is larger (or smaller) than the number of stored data, and the determination unit stores If the data number is determined to be larger (or smaller) than the data number, the means for storing the received number in the database together with the received data and the determination means are less than or equal to the stored data number. If it is determined that the number of the received data is discarded, and the data number stored in the database is transmitted to another distribution device, the stored data number is sent together. Characterized in that it comprises means for.

  A vehicle-mounted communication method according to a fourth aspect of the invention includes a plurality of vehicle-mounted devices that transmit and receive data, and data received from each vehicle-mounted device connected to the vehicle-mounted device, stored in a database, and the stored data to each vehicle-mounted device. An in-vehicle communication method in an in-vehicle communication system including a plurality of distribution devices for distribution, wherein a part or all of the in-vehicle device is connected to each of the plurality of distribution devices and transmits data to each distribution device. In this case, a number is assigned to the data, the number is incremented (or decreased), and the distribution device transmits the data stored in the database together with the stored data number to the other distribution devices, When data is received from each in-vehicle device or other distribution device, it is determined whether the data number received together is larger (or smaller) than the stored data number, and stored When it is determined that the number is larger (or smaller) than the data number, the received data number is stored in the database together with the received data, and the data number is determined to be less than (or greater than) the stored data number. The received data is discarded.

  A vehicle-mounted communication method according to a fifth aspect of the present invention is a plurality of vehicle-mounted devices that transmit and receive data, and is connected to the vehicle-mounted device, receives data from each vehicle-mounted device, stores it in a database, and stores the stored data to each vehicle-mounted device. An in-vehicle communication method in an in-vehicle communication system including a plurality of distribution devices to distribute, wherein a part or all of the in-vehicle devices are respectively connected to the plurality of distribution devices and transmit the same data to each distribution device. The in-vehicle device and the distribution device follow a common predetermined cycle, and in the data transmission period within the predetermined cycle, the in-vehicle device assigns a number to the data, and increases (or decreases) the number. When each of the distribution devices receives data from each on-vehicle device, the distribution device determines whether the data number received together is larger (or smaller) than the stored data number. When it is determined that the number is larger (or smaller) than the stored data number, the received number is stored in the database together with the received data, and it is determined that the stored data number is less than (or higher). The received data is discarded, and in the remaining period of the predetermined cycle, each distribution device transmits the data stored in the database to the other distribution devices together with the stored data number. When data is received from each in-vehicle device or other distribution device, it is determined whether the data number received together is larger (or smaller) than the stored data number, and the stored data If it is determined that the number is larger (or smaller) than the number of the received data, the received data number is stored in the database together with the received data, and the stored data number is less than (or higher). If it is determined that that, characterized by discarding the received data.

  In the present invention, a plurality of distribution devices that receive data transmitted from the in-vehicle device and store it in the database, and distribute the data received and stored from the in-vehicle device to other in-vehicle devices are provided, and the in-vehicle device A plurality of distribution devices are connected to some or all of the devices. That is, the connection relationship between each in-vehicle device and the distribution device is multiplexed. Data of the same content is transmitted from each in-vehicle device to a plurality of distribution devices connected thereto, and the data received by the distribution device is stored in each database.

  Further, according to the present invention, database data is transmitted and received between distribution devices. Thereby, the data contents of the database are synchronized among the plurality of distribution devices.

  In the present invention, when data is directly transmitted from an in-vehicle device connected to each distribution device, and after data is transmitted once to another distribution device and stored, the data is synchronized for the database of the distribution device. May be sent. That is, the same data is transmitted to one distribution device with a time difference. In the present invention, when data is transmitted from the in-vehicle device, a number is assigned to the data, and the number is increased (or decreased) each time the data is transmitted. When the distribution device receives data from the in-vehicle device, the number received together is also stored in the database, and when the data is transmitted to another distribution device, the number stored together is also transmitted. When data is received from the in-vehicle device and the distribution device by the distribution device, the latest data depends on whether the data number received together with the received data is larger (or smaller) than the data number already stored. Whether or not the data is determined is determined. Only when it is determined that the data is the latest data, the data is stored. At other times, the data is discarded.

  Furthermore, in the present invention, when the transmission of data from the in-vehicle device to the distribution device and the exchange of data from the distribution device to the distribution device are sequentially performed according to the cycle, the same data is directly received from the in-vehicle device by one distribution device. And received multiple times when received via another distribution device for database synchronization. In the present invention, the distribution device determines whether or not the latest data is based on whether or not the number received together with the data is larger (or smaller) than the stored data number. Only when it is determined that the data is stored, the data is discarded.

  According to the present invention, since the connection relationship between the distribution device and a part or all of the in-vehicle devices is multiplexed, a problem occurs in any of the plurality of distribution devices, and data is not distributed from the distribution device Even in this case, data can be distributed from other distribution devices. Therefore, by providing the distribution device, not only can the identity of the data received by each in-vehicle device be ensured, but if any of the distribution devices fails, the connection between the distribution device and the in-vehicle device is hindered. If a failure occurs in a part of the system, for example, the occurrence of a failure in the operation of the entire in-vehicle communication system can be prevented, and the reliability of the system can be improved.

  In the case of the present invention, since the database possessed by each distribution device is synchronized in the connection relationship between the multiplexed distribution device and each in-vehicle device, the content of data transmitted from the distribution device is different. Can be prevented, the identity of data can be ensured, and the reliability of data transmitted and received in the in-vehicle communication system can be improved.

  According to the present invention, in the connection relationship between the multiplexed distribution device and each in-vehicle device, when data is transmitted from the in-vehicle device to the distribution device and when data is exchanged between the distribution devices, the distribution device is the latest Since it is stored in the database only when it is determined to be data, it is possible to prevent new data from being updated with old data and to improve the reliability of data transmitted and received in the in-vehicle communication system.

  Furthermore, according to the present invention, when the in-vehicle device and the distribution device transmit data from the in-vehicle device to the distribution device and exchange data between the distribution devices according to a common cycle, the distribution device is the in-vehicle device and other distribution devices. Although the same data is received from the apparatus, it is stored only when it is determined that it is the latest data, so that the reliability of the data can be improved.

  Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof.

  FIG. 1 is a schematic diagram showing a configuration of an in-vehicle communication system according to the present invention. The in-vehicle communication system includes an ECU (Electronic Control Unit), a sensor, and the like, and is connected to a plurality of in-vehicle devices 1a, 1b, and 1c and in-vehicle devices 1a, 1b, and 1c. Distribution devices 2a, 2b that receive data from 1b, 1c and distribute the data to other in-vehicle devices 1a, 1b, 1c and other in-vehicle devices (not shown); in-vehicle devices 1a, 1b, 1c, and distribution device 2a; Is configured to include an in-vehicle communication line 3a for connecting the vehicle-mounted devices 1a, 1b, 1c and the distribution device 2b, and a communication line 4 for connecting the distribution devices 2a, 2b. . In FIG. 1, the in-vehicle communication line 3b is indicated by a broken line to distinguish it from the in-vehicle communication line 3a. Moreover, the white arrow in FIG. 1 represents the example of transmission / reception of the data between the vehicle-mounted apparatus 1a and distribution apparatus 2a, 2b.

  The in-vehicle devices 1a, 1b, and 1c are devices that can transmit data including numerical information of various physical quantities such as measured values, calculated values, and control values, or can be controlled by a microcomputer such as an engine and a brake. For example, one in-vehicle device 1a includes a sensor (not shown) that detects the vehicle speed, and transmits data of the detected vehicle speed to the distribution devices 2a and 2b.

  The distribution devices 2a and 2b have storage areas used as the databases 21a and 21b, store data transmitted from the in-vehicle devices 1a, 1b, and 1c in the databases 21a and 21b, and read data from the databases 21a and 21b. Is transmitted to the in-vehicle devices 1a, 1b, 1c. By storing the data in the distribution devices 2a and 2b in a unified manner, it is possible to reduce the communication load and ensure the identity of the contents of the data distributed to the in-vehicle devices 1a, 1b and 1c.

  Distribution device 2a, 2b is connected with other vehicle equipment groups which are not illustrated, and may transmit data received from vehicle equipment 1a, 1b, 1c to other vehicle equipment groups. In this case, the data to be transmitted to the other in-vehicle devices is not all the data transmitted from the in-vehicle devices 1a, 1b, 1c, but only the data necessary for the other in-vehicle devices is read from the databases 21a, 21b and transmitted. By adopting the configuration, the communication load in the in-vehicle communication system is reduced. Further, the data stored in the databases 21a and 21b and read from the databases 21a and 21b are distributed, so that the contents of data received by the in-vehicle devices 1a, 1b and 1c and other in-vehicle devices are the same. Sex is guaranteed. Furthermore, data simultaneity is ensured by transmitting data from the distribution devices 2a and 2b to the respective in-vehicle devices connected to the plurality of groups in a lump.

  The topology of the in-vehicle communication lines 3a, 3b connecting the in-vehicle devices 1a, 1b, 1c and the distribution devices 2a, 2b and the communication line 4 connecting the distribution devices 2a, 2b are bus type and star type. Any form such as a daisy chain type may be used. The in-vehicle devices 1a, 1b, and 1c can transmit and receive data to and from the distribution devices 2a and 2b and the in-vehicle communication lines 3a and 3b. The distribution devices 2a and 2b transmit and receive data to and from each other via the communication line 4. Is possible.

  In the in-vehicle communication system according to the present invention, as shown in the schematic diagram of FIG. 1, each on-vehicle device 1a, 1b, 1c is connected to both the distribution device 2a and the distribution device 2b via in-vehicle communication lines 3a and 3b. And send data to both. For example, the in-vehicle device 1a transmits vehicle speed data to both the distribution device 2a and the distribution device 2b. The same data is transmitted and stored in both distribution device 2a and distribution device 2b, including data transmitted by other in-vehicle device groups. Thereby, the in-vehicle devices 1a, 1b, and 1c can receive data not only from the distribution device 2a but also from the distribution device 2b.

  Therefore, as shown in the schematic diagram of FIG. 1, when a hardware failure such as memory occurs in the distribution device 2a and data cannot be read from the database 21a, or between the distribution device 2a and the in-vehicle communication line 3a Even when a failure occurs in the distribution device 2a, such as when the connection fails and the in-vehicle devices 1a, 1b, 1c cannot transmit or receive data from the distribution device 2a, the in-vehicle devices 1a, 1b, 1c can transmit / receive data to / from the distribution device 2b. Thus, in the in-vehicle communication system of the present invention, the in-vehicle communication system as a whole operates in a fail-safe state by duplicating the connection relationship between the in-vehicle devices 1a, 1b, 1c and the distribution devices 2a, 2b, that is, the databases 21a, 21b. And the reliability of the system is improved.

  Furthermore, in the in-vehicle communication system according to the present invention, it is desirable to transmit / receive data read from the respective databases 21a, 21b between the distribution devices 2a, 2b and to synchronize the contents of the databases 21a, 21b. Both the distribution device 2a and the distribution device 2b are connected to the vehicle-mounted devices 1a, 1b, 1c and other vehicle-mounted device groups with the completely same configuration, and data is normally transmitted from the vehicle-mounted devices 1a, 1b, 1c,. The contents of the databases 21a and 21b are the same. However, for example, when the in-vehicle devices connected to other than the in-vehicle devices 1a, 1b, and 1c are different, the transmitted data is different, and the contents of the databases 21a and 21b may not be the same. If the contents of the databases 21a and 21b are not the same, the in-vehicle devices 1a, 1b, and 1c need to determine which of the data transmitted from the distribution devices 2a and 2b is correct (latest) data. Reliability decreases. Further, when the distribution device 2a and the distribution device 2b are separately connected to in-vehicle devices other than the in-vehicle devices 1a, 1b, and 1c, the data transmitted from these in-vehicle devices is also shared by the in-vehicle devices 1a, 1b, and 1c. In addition to the in-vehicle devices 1a, 1b, and 1c, when the same data is used between the in-vehicle devices that are separately connected to the distribution device 2a and the distribution device 2b, the data content is identical. Is secured.

  FIG. 2 is a block diagram showing an internal configuration of the in-vehicle device 1a and the distribution device 2a constituting the in-vehicle communication system according to the present invention. Since the in-vehicle devices 1b and 1c have the same internal configuration as the in-vehicle device 1a, detailed description thereof is omitted, and the distribution device 2b has the same internal configuration as the distribution device 2a, and thus detailed description thereof is omitted.

  The in-vehicle device 1a includes a control unit 10a that controls the operation of each component described below, a power supply circuit 11a that supplies power to each component, and a volatile memory such as a DRAM (Dynamic Random Access Memory). Unit 12a, a first communication control unit 13a connected to the in-vehicle communication line 3a, and a second communication control unit 14a connected to the in-vehicle communication line 3b.

  The control unit 10a of the in-vehicle device 1a receives power supply from a power supply device such as a vehicle alternator and a battery (not shown) via the power supply circuit 11a, reads and executes a control program stored in the storage unit 12a, Controls the operation of each component.

  The storage unit 12a of the in-vehicle device 1a temporarily stores various information such as control values and calculation values generated by the processing of the control unit 10a, or measured values of physical quantities represented by signals input from sensors (not shown). The

  In the case of the present invention, the storage unit 12a of the in-vehicle device 1a stores a sequence number of data to be added to data to be transmitted. When transmitting data, the control unit 10a of the in-vehicle device 1a reads out the sequence number stored in the storage unit 12a and transmits it together with the data. In the present embodiment, the sequence number is stored as a positive integer value (0 to 255) using a 1-byte memory. The initial value of the sequence number is set to zero, and the control unit 10a increments the sequence number by one every time data is transmitted. If the sequence number is increased to 255, then it is reset to zero. Note that the sequence number may be increased before or after data transmission. After transmitting data, the control unit 10a stores the sequence number increased before or after transmission in the storage unit 12a.

  The first communication control unit 13a of the in-vehicle device 1a realizes data transmission / reception with the distribution device 2a connected via the in-vehicle communication line 3a. The in-vehicle device 1a may be configured such that the first communication control unit 13a can directly transmit / receive data to / from the other in-vehicle devices 1b and 1c via the in-vehicle communication line 3a. The second communication control unit 14a realizes data transmission / reception between the distribution device 2b and the in-vehicle device 1a connected via the in-vehicle communication line 3b.

  The control unit 10a of the in-vehicle device 1a transmits data together with the sequence number of the data stored in the storage unit 12a by the first communication control unit 13a and the second communication control unit 14a. In addition, the control part 10a of the vehicle-mounted apparatus 1a transmits data including a message in a predetermined format.

  The distribution device 2a includes a control unit 20a that controls the operation of each component described below, a power supply circuit 22a that supplies power to each component, and a memory that includes a volatile memory such as a DRAM (Dynamic Random Access Memory). Unit 23a, a first communication control unit 24a connected to the in-vehicle communication line 3a, and a second communication control unit 25a connected to the communication line 4.

  The control unit 20a of the distribution device 2a receives power supply from a power supply device such as a vehicle alternator and battery (not shown) via the power supply circuit 22a, reads and executes the control program stored in the storage unit 23a, Controls the operation of each component.

  The storage unit 23a of the distribution device 2a is provided with a storage area for a database 21a that stores data received by the control unit 20a from the in-vehicle devices 1a, 1b, and 1c. For each type (data ID) such as “vehicle speed” and “steering angle” from the received data, the control unit 20a stores corresponding specific measured values, calculated values, control values, and sequence numbers of data described later in the database 21a. Remember. As will be described later, the control unit 20a of the distribution device 2a may discard the data without storing it in the database 21a. This process will be described later.

  The first communication control unit 24a of the distribution device 2a implements data transmission / reception with each of the in-vehicle devices 1a, 1b, 1c connected via the in-vehicle communication line 3a. The second communication control unit 25 a implements data transmission / reception with the distribution device 2 b connected via the communication line 4. In the present embodiment, the control unit 20a of the distribution device 2a stores data read from the database 21a by the second communication control unit 25a to the distribution device 2b for each data type in the database 21a. Read the sequence number and send it together.

  FIG. 3 is an explanatory view schematically showing a format of a message transmitted / received between the in-vehicle devices 1a, 1b, 1c and the distribution devices 2a, 2b constituting the in-vehicle communication system according to the present invention.

  As shown in the explanatory diagram of FIG. 3, a message transmitted from the in-vehicle devices 1a, 1b, and 1c starts with a predetermined header, and includes a sequence number, data (payload), and finally a trailer indicating the end of the message. The The distribution device 2a reads the data and the sequence number assigned to the data from the message transmitted from the in-vehicle device 1a, 1b, 1c or another distribution device 2b according to the format shown in the explanatory diagram of FIG. Can do. The sequence number may be included in the data.

  Moreover, the vehicle-mounted devices 1a, 1b, 1c and the distribution devices 2a, 2b in the present embodiment operate synchronously based on a shared cycle by having synchronized timers. Therefore, the control units 10a, 10b, 10c of the in-vehicle devices 1a, 1b, 1c and the control units 20a, 20b of the distribution devices 2a, 2b function as timers according to a built-in clock (not shown). FIG. 4 shows an example of a predetermined cycle that is followed when the control units 10a, 10b, 10c, 20a, and 20b of the in-vehicle devices 1a, 1b, and 1c and the distribution devices 2a and 2b in the present embodiment function as timers. It is explanatory drawing shown typically. The horizontal axis represents the passage of time, and each rectangle represents a divided period.

  In the example shown in the explanatory diagram of FIG. 4, one cycle is, for example, several tens of milliseconds. One period is a synchronization slot in which data is transmitted and received between the distribution devices 2a and 2b and the databases 21a and 21b are synchronized, and from the in-vehicle devices 1a, 1b and 1c to the distribution devices 2a and 2b and from the distribution devices 2a and 2b. It is divided into transmission slots that are periods for transmitting data to the in-vehicle devices 1a, 1b, and 1c. Periods A, C, and E shown in the explanatory diagram of FIG. 4 are transmission slots, and periods B, D, and F are synchronization slots. The control units 10a, 10b, 10c and the control units 20a, 20b of the in-vehicle devices 1a, 1b, 1c and the distribution devices 2a, 2b recognize the synchronization slot and the transmission slot by functioning as a timer.

  During the synchronization slot, data transmission / reception is not performed between the distribution devices 2a, 2b and the in-vehicle devices 1a, 1b, 1c, and data stored in the databases 21a, 21b is transmitted / received between the distribution devices 2a, 2b, By exchanging data, the databases 21a and 21b are synchronized. In the present embodiment, the synchronization procedure of the databases 21a and 21b is not limited. At the end of the synchronization slot, the contents of the database 21a of the distribution device 2a and the contents of the database 21b of the distribution device 2b are synchronized.

  In the in-vehicle communication system according to the present invention configured as described above, each in-vehicle device 1a, 1b, 1c includes data in a message and transmits it to the distribution devices 2a, 2b, and the distribution device 2a receives data from the database 21a. Processing to read and include in a message and transmit to the distribution device 2b, and processing when the distribution device 2b receives a message transmitted from each of the in-vehicle devices 1a, 1b, 1c and the distribution device 2a will be described.

  In the in-vehicle communication system of the present invention, as described above, each of the in-vehicle devices 1a, 1b, 1c is connected to both the distribution device 2a and the distribution device 2b, and the same data, for example, a message including vehicle speed data is transmitted to both. To do. In this case, a collision occurs in the in-vehicle communication line 3b, a message to one distribution device 2b is significantly delayed, and the data may already be old data when the data is transmitted to the distribution device 2b. On the other hand, in the present invention, as described above, each vehicle-mounted device 1a, 1b, 1c is given a sequence number to the data and transmitted together, and the sequence number is increased each time transmission is performed. The devices 2a and 2b can recognize that the data to which the higher sequence number is assigned is the latest. Accordingly, the distribution devices 2a and 2b store only the latest data in the databases 21a and 21b, and discard other data.

  Hereinafter, processing performed by the control units 20a and 20b of the in-vehicle devices 1a, 1b, and 1c and the distribution devices 2a and 2b during the transmission slot and the synchronization slot will be described with reference to flowcharts. 5 and 6 are flowcharts showing a processing procedure in which data is transmitted and received between the in-vehicle device 1a and the distribution device 2a during the transmission slot in the in-vehicle communication system according to the present embodiment. Since the processing procedure that the in-vehicle devices 1b and 1c transmit to the distribution devices 2a and 2b is the same as the processing procedure by the in-vehicle device 1a, detailed description thereof is omitted. Further, the processing procedure for the distribution device 2b to receive a message from the in-vehicle devices 1a, 1b, 1c is the same as the processing procedure by the distribution device 2a, and detailed description thereof will be omitted.

  The control unit 10a of the in-vehicle device 1a functions as a timer to determine whether a transmission slot has arrived (step S101). When determining that the transmission slot has not arrived (S101: NO), the control unit 10a of the in-vehicle device 1a returns the process to step S101 and waits until it is determined that the transmission slot has arrived.

  When it is determined that the transmission slot has arrived (S101: YES), the control unit 10a of the in-vehicle device 1a reads data such as measurement values, calculation values, control values, and the like temporarily stored in the storage unit 12a (Step S101). S102). The control unit 10a of the in-vehicle device 1a reads the sequence number stored in the storage unit 12a (Step S103), increments the read sequence number by 1 (Step S104), and reads the read data and the increased sequence number. A message including the message is generated (step S105), and the generated message is transmitted to the distribution devices 2a and 2b via the in-vehicle communication lines 3a and 3b by the first communication control unit 13a and the second communication control unit 14a (step S106). ).

  The control unit 20a of the distribution device 2a receives the message transmitted from the connected in-vehicle device 1a by the first communication control unit 24a (step S107), and reads out the data and the sequence number of the data from the received message (step S107). S108). The control unit 20a of the distribution device 2a reads the sequence number of the data already stored in the database 21a corresponding to the data read from the received message (step S109) and compares it with the sequence number read in step S108 ( Step S110).

  The control unit 20a of the distribution device 2a determines whether or not the sequence number of the data read from the received message is larger than the sequence number of the data read from the database 21a (Step S111). When the control unit 20a of the distribution device 2a determines that the sequence number of the data read from the received message is larger than the sequence number of the read data (S111: YES), the data read from the received message and both The sequence number read from the message is stored in the database 21a (step S112), and the process ends.

  When it is determined that the sequence number of the data read from the received message is equal to or less than the sequence number of the read data (S111: NO), the control unit 20a of the distribution device 2a discards the data read from the received message. (Step S113), the process ends.

  In the determination processing in step S111, the control unit 20a of the distribution device 2a has a larger sequence number than the read data when the sequence number of the data read from the received message is a number after zero reset. Judge.

  7 and 8 are flowcharts showing a processing procedure in which data is transmitted and received between the distribution devices 2a and 2b during the synchronization slot in the in-vehicle communication system according to the present embodiment. The processing procedure after the processing in which the distribution device 2b receives a message from another distribution device 2a is the same as the processing procedure in the case of receiving a message from the in-vehicle devices 1a, 1b, 1c. Accordingly, the processing procedure after the distribution device 2b receives the message from the distribution device 2a in the processing procedures shown in the flowcharts of FIGS. 7 and 8 is the same as the processing procedure shown in the flowcharts of FIGS. Step numbers are assigned and detailed description is omitted.

  The control unit 20a of the distribution device 2a functions as a timer to determine whether or not a synchronization slot has arrived (step S201). When determining that the synchronization slot has not arrived (S201: NO), the control unit 20a of the distribution device 2a returns the process to step S201 and waits until determining that the synchronization slot has arrived.

  When determining that the synchronization slot has arrived (S201: YES), the control unit 20a of the distribution device 2a reads out the data stored in the database 21a of the storage unit 23a and the sequence number of the data (step S202). The control unit 20a of the distribution device 2a generates a message including the read data and the sequence number (step S203), and transmits the generated message to the distribution device 2b by the second communication control unit 25a (step S204).

  Thereafter, the control unit 20b of the distribution device 2b receives the message from the distribution device 2a by the process of step S107 (S107). Similarly to the case where the message is received from the in-vehicle device 1a, the control unit 20b reads the data and sequence number from the message (S108). The sequence number of the data stored in the database 21b is read (S109) and compared (S110), and it is determined that the sequence number of the data read from the received message is larger than the sequence number of the data stored in the database 21b. If it is (S111: YES), the data is stored (S112), and if it is determined that it is less than or equal to the sequence number of the stored data (S111: NO), the data is discarded (S113) and the synchronization process is terminated. To do.

  Further, the control unit 20b of the distribution device 2b generates a message based on the data read from the database 21b and transmits it to the distribution device 2a. The control unit 20a of the distribution device 2a includes the data received from the distribution device 2b. Only the latest data is stored in the database 21a. Thereby, data is exchanged between the distribution apparatuses 2a and 2b, and the contents of the databases 21a and 21b are synchronized.

  Next, as a specific example of the processing as described above, data having the vehicle type as the vehicle speed is transmitted by the control unit 10a of the in-vehicle device 1a, the vehicle speed data is received by the distribution devices 2a and 2b, and the distribution device 2a. , 2b will be described as an example. FIG. 9, FIG. 10 and FIG. 11 are explanatory diagrams schematically showing processes in which data is transmitted and received between the in-vehicle device 1a and the distribution devices 2a and 2b constituting the in-vehicle communication system of the present invention and stored.

  9A is a period A among the periods shown in the explanatory diagram of FIG. 4, FIG. 9B is a period B, FIG. 10A is a period C, and FIG. 10B is a period D. FIG. 11A shows processing in the period E. 9 (a), FIG. 9 (b), FIG. 10 (a), FIG. 10 (b), and FIG. 11 (a), the in-vehicle device 1a and the distribution constituting the in-vehicle communication system according to the present invention, respectively. The connection relationship between the devices 2a and 2b, the contents of messages transmitted from the in-vehicle device 1a to the distribution devices 2a and 2b, and the data stored in the databases 21a and 21b provided in the distribution devices 2a and 2b, respectively. An example of the contents is shown in a table.

  First, in the period A that is a transmission slot, as shown in the explanatory diagram of FIG. 9A, the control unit 10a of the in-vehicle device 1a performs the vehicle speed data (value = 20) and the sequence number “100” given to the vehicle speed data. Is transmitted to the distribution device 2a and the distribution device 2b via the in-vehicle communication lines 3a and 3b. The sequence number “100” is a number increased by 1. The control unit 20a of the distribution device 2a receives the message transmitted from the in-vehicle device 1a and updates the database 21a. As a result, the vehicle speed data stored in the database 21a of the distribution device 2a is updated to data having a value of “20” and a sequence number of “100”. On the other hand, in the period A, because the in-vehicle communication line 3b is in a congested state, for example, the control unit 20b of the distribution device 2b cannot receive the message transmitted from the in-vehicle device 1a, the database 21b is not updated, The vehicle speed data stored in the database 21b of the distribution device 2b has a value “10” and a sequence number “99”.

  Next, in the period B which is a synchronization slot, data is transmitted and received between the distribution devices 2a and 2b via the communication line 4 and synchronized as shown in the explanatory diagram of FIG. 9B. Here, the control unit 20a of the distribution device 2a generates a message including the vehicle speed data value “20” and the stored sequence number “100” from the database 21a, and transmits the message to the distribution device 2b. The control unit 20b of the distribution device 2b compares the sequence number “100” of the vehicle speed data included in the message received from the distribution device 2a with the sequence number “99” of the vehicle speed data stored in the database 21b. Since the control unit 20b of the distribution device 2b determines that the sequence number “100” of the data included in the received message is greater than the sequence number “99” of the stored vehicle speed data, the value of the received vehicle speed data “20” and the sequence number “100” are stored in the database 21b. Thereby, the databases 21a and 21b of the distribution devices 2a and 2b are synchronized with the latest data.

  Next, in the period C which is a transmission slot, as shown in the explanatory diagram of FIG. 10A, the control unit 10a of the in-vehicle device 1a generates a message including vehicle speed data (value = 45). At this time, the control unit 10a of the in-vehicle device 1a generates a message by including the sequence number “101” obtained by incrementing the sequence number “100” of the previously transmitted data by 1 in the vehicle speed data, and transmits the message to the distribution devices 2a and 2b. To do. The control units 20a and 20b of the distribution devices 2a and 2b receive the message transmitted from the in-vehicle device 1a, and the vehicle speed data sequence number “101” included in the message and the vehicle speed data stored in the databases 21a and 21b. The sequence number “100” is compared. The control units 20a and 20b of the distribution devices 2a and 2b determine that the sequence number “101” of the data included in the received message is greater than the sequence number “100” of the stored vehicle speed data. The vehicle speed data value “45” and sequence number “101” included in the received message are stored in the databases 21a and 21b and updated.

  Next, in the period D that is a synchronization slot, data is transmitted and received between the distribution devices 2a and 2b and synchronized as shown in the explanatory diagram of FIG. Even during this period, the control unit 20a of the distribution device 2a generates a message including the vehicle speed data value “45” and the stored sequence number “101” from the database 21a, and transmits the message to the distribution device 2b. Similar to the processing in the period B, the control unit 20b of the distribution device 2b includes the sequence number “101” of the vehicle speed data included in the message received from the distribution device 2b and the sequence number “101” of the vehicle speed data stored in the database 21b. ". However, during the period D, the control unit 20b of the distribution device 2b determines that the sequence number “101” of the data included in the received message is equal to or less than the sequence number “101” of the stored vehicle speed data. The vehicle speed data and sequence number included in the received message are discarded. Since it has the same content as the stored data and is already synchronized, it is not updated.

  Next, in the period E which is a transmission slot, as shown in the explanatory diagram of FIG. 11A, the vehicle speed data (value = 20) and the sequence number “100” transmitted in the period A by the control unit 10a of the in-vehicle device 1a. Is retransmitted to the distribution device 2b via the in-vehicle communication line 3b. The control unit 20b of the distribution device 2b receives the retransmitted message. The control unit 20b of the distribution device 2b compares the sequence number “100” of the vehicle speed data included in the received message with the sequence number “101” of the vehicle speed data stored in the database 21b. In this case, the control unit 20b of the distribution device 2b determines that the sequence number “100” of the data included in the received message is equal to or less than the sequence number “101” of the stored vehicle speed data. The vehicle speed data and sequence number included in are discarded.

  As described above, the distribution device 2b receives messages including the same data from the in-vehicle devices 1a, 1b, and 1c and the distribution device 2a during the transmission slot and the synchronization slot, respectively. In the case of the present invention, the in-vehicle devices 1a, 1b, and 1c are transmitted together with a sequence number assigned to the data, and the sequence number is increased each time transmission is performed. Accordingly, the distribution device 2b recognizes that the data to which the larger sequence number is assigned is the latest data, and the sequence number of the data of the received message is assigned to the data stored in the database 21b. Only when it is determined that the number is larger than the sequence number, the data is stored in the database 21b. By this processing, it is possible to avoid the distribution device 2b updating new data with old data, and connect the connection relationship with the database for the in-vehicle devices 1a, 1b, and 1c to both the database 21a and the database 21b. Thus, the reliability of the data can be further improved while the data reliability is improved by duplication.

  In this embodiment, the in-vehicle communication line is also duplicated by the in-vehicle communication lines 3a and 3b. However, the present invention is not limited to this, and the distribution devices 2a and 2b and the in-vehicle devices 1a, 1b, and 1c may all be connected to one in-vehicle communication line. In this case, the in-vehicle devices 1a, 1b, and 1c do not need to include two communication control units, but are connected to the in-vehicle communication line via one communication control unit, and distribute data via the one in-vehicle communication line. It may be configured to transmit to 2a and distribution device 2b. Even if the distribution device 2a fails for some reason, the in-vehicle devices 1a, 1b, and 1c can receive data from the distribution device 2b, and the reliability of the system is improved.

  In the present embodiment, all the in-vehicle devices 1a, 1b, and 1c are connected to the plurality of distribution devices 2a and 2b. However, the present invention is not limited to this, and only a part of the in-vehicle devices 1a, 1b, and 1c may be connected to the plurality of distribution devices 2a and 2b. For example, only the in-vehicle device 1a is connected to the distribution device 2a and the distribution device 2b, the in-vehicle device 1b is connected only to the in-vehicle communication line 3a and can transmit / receive data only to / from the distribution device 2a, and the in-vehicle device 1b is in-vehicle communication line A configuration in which data can be transmitted / received only to / from the distribution device 2b by connecting only to 3b may be used.

  Moreover, in this Embodiment, when the vehicle equipment 1a, 1b, 1c transmits data, it was set as the structure which increases the number provided to data, every time it transmits. However, the present invention is not limited to this, and the number may be decreased each time data is transmitted, and the smaller the number, the more recent data can be determined. In this case, the control units 20a and 20b of the distribution devices 2a and 2b store in the database when the value of the number assigned to the received data is smaller than the stored data number, and exceed the stored number. If it is, discard the data.

It is a schematic diagram which shows the structure of the vehicle-mounted communication system which concerns on this invention. It is a block diagram which shows the internal structure of the vehicle equipment and distribution device which comprise the vehicle-mounted communication system which concerns on this invention. It is explanatory drawing which represents typically the format of the message transmitted / received between the vehicle equipment and distribution device which comprise the vehicle-mounted communication system which concerns on this invention. It is explanatory drawing which shows typically the example of the predetermined | prescribed period followed when the control part of each vehicle-mounted apparatus and each distribution apparatus in this Embodiment functions as a timer. It is a flowchart which shows the process sequence in which data is transmitted / received between a vehicle-mounted apparatus and a distribution device in the period of a transmission slot in the vehicle-mounted communication system in this Embodiment. It is a flowchart which shows the process sequence in which data is transmitted / received between a vehicle-mounted apparatus and a distribution device in the period of a transmission slot in the vehicle-mounted communication system in this Embodiment. It is a flowchart which shows the process sequence in which the data are transmitted / received between distribution devices in the period of a synchronous slot in the vehicle-mounted communication system in this Embodiment. It is a flowchart which shows the process sequence in which the data are transmitted / received between distribution devices in the period of a synchronous slot in the vehicle-mounted communication system in this Embodiment. It is explanatory drawing which shows typically the process by which data is transmitted / received between the vehicle equipment and distribution device which comprise the vehicle-mounted communication system of this invention, and is memorize | stored. It is explanatory drawing which shows typically the process by which data is transmitted / received between the vehicle equipment and distribution device which comprise the vehicle-mounted communication system of this invention, and is memorize | stored. It is explanatory drawing which shows typically the process by which data is transmitted / received between the vehicle equipment and distribution device which comprise the vehicle-mounted communication system of this invention, and is memorize | stored.

Explanation of symbols

1a, 1b, 1c In-vehicle device 10a, 10b, 10c Control unit 12a, 12b, 12c Storage unit 2a, 2b Distribution device 20a, 20b Control unit 21a, 21b Database 23a, 23b Storage unit 3a, 3b In-vehicle communication line 4 Communication line

Claims (5)

A plurality of in-vehicle devices that transmit and receive data, a plurality of distribution devices that are connected to the in-vehicle devices, receive data from each in-vehicle device, store the data in a database, and distribute the stored data to each in-vehicle device An in-vehicle communication system comprising:
Part or all of the in-vehicle device is
Connected to each of the plurality of distribution devices,
An in-vehicle communication system comprising means for transmitting the same data to each distribution device. Each of the dispensing devices is
Means for transmitting data stored in the database to another distribution device;
The vehicle-mounted communication system according to claim 1, further comprising means for storing data transmitted from another distribution device in the database. Each in-vehicle device transmits data,
Means for assigning numbers to the data;
Means for increasing (or decreasing) the number,
Each dispensing device
When data is received from an in-vehicle device or other distribution device,
Determining means for determining whether the number of data received together is larger (or smaller) than the number of stored data;
Means for storing the received number in the database together with the received data when the determining means determines that it is larger (or smaller) than the stored data number;
Means for discarding the received data if the determining means determines that the data number is less than or equal to the stored data number (or more);
The vehicle-mounted communication system according to claim 1, further comprising: a unit that transmits the stored data number together with the data stored in the database when the data is transmitted to another distribution device. In-vehicle including a plurality of in-vehicle devices that transmit and receive data, and a plurality of distribution devices that are connected to the in-vehicle devices, receive data from each in-vehicle device, store the data in a database, and distribute the stored data to each in-vehicle device An in-vehicle communication method in a communication system,
Part or all of the in-vehicle device is
Connected to each of the plurality of distribution devices,
When sending data to each distributor,
Number the data,
Increase (or decrease) the number,
The distributor is
Send the data stored in the database to the other distribution device together with the number of the stored data,
When data is received from each in-vehicle device or other distribution device,
Determine whether the number of data received together is larger (or smaller) than the number of stored data,
If it is determined that it is larger (or smaller) than the stored data number, the received data number is stored in the database together with the received data.
An in-vehicle communication method characterized by discarding received data when it is determined that the number is less than or equal to the number of stored data. In-vehicle including a plurality of in-vehicle devices that transmit and receive data, and a plurality of distribution devices that are connected to the in-vehicle devices, receive data from each in-vehicle device, store the data in a database, and distribute the stored data to each in-vehicle device An in-vehicle communication method in a communication system,
A part or all of the in-vehicle device is connected to each of the plurality of distribution devices and transmits the same data to each distribution device,
The in-vehicle device and the distribution device follow a predetermined cycle in common,
During the data transmission period within the predetermined period,
The in-vehicle device is
Number the data,
Increase (or decrease) the number and send it to each distribution device,
Each dispensing device
When data is received from each in-vehicle device,
Determine whether the data number received together is larger (or smaller) than the stored data number;
When it is determined that the number is larger (or smaller) than the stored data number, the received number is stored in the database together with the received data.
If it is determined that it is less than or equal to the number of stored data, discard the received data,
In the remaining period of the predetermined period,
Each dispensing device
Send the data stored in the database to the other distribution device together with the number of the stored data,
When data is received from each in-vehicle device or other distribution device,
Determine whether the number of data received together is larger (or smaller) than the number of stored data,
If it is determined that it is larger (or smaller) than the stored data number, the received data number is stored in the database together with the received data.
An in-vehicle communication method characterized by discarding received data when it is determined that the number is less than or equal to the number of stored data.

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