Communication system

Abstract

This communication system comprises: a domain controller 10 connected to a bus 10a in a global area 100 and a bus 10b in a local area 201; ECUs (such as a domain controller 20) belonging to the global area 100; and ECUs (such as ECUs 11, 12) belonging to the local area 201. The domain controller 10 receives a data frame 31 including a CAN ID (ID: 100) and control information (A, B) to be processed by the ECU 12 from the bus 10a, generates a data frame 34 including a CAN ID (ID: 300) different from the CAN ID (ID: 100), the control information (A, B), and control information (P), and transmits the data frame 34 from the bus 10b.

Description

communication systems

[0001] The present invention relates to a communication system for transmitting and receiving data frames over a communication network.

[0002] As a message processing technology for relaying messages between electronic control units, an in-vehicle network system such as that disclosed in Patent Document 1 is known. In this in-vehicle network system, the gateway includes a receiver that sequentially receives first-type frames from a bus of a CAN network, a determination unit that determines whether data in the first-type frames received by the receiver should be transmitted to an Ethernet (registered trademark) network, and a transmitter that transmits, to the Ethernet network, second-type frames that include data for each of the plurality of first-type frames determined by the determination unit to be transmitted to the Ethernet network.

[0003] International Publication No. 2017 / 203902

[0004] With the recent increase in the complexity of electronic control, the number of frame IDs transmitted and received between electronic control units (ECUs) is increasing. In the in-vehicle network system described in Patent Document 1, first-class frames are transmitted and received over a CAN network, but there is an upper limit to the number of frame IDs in the CAN, which causes a problem of a shortage of available frame IDs within the network.

[0005] The problem to be solved by the present invention is to provide a communication system that can increase the number of available frame IDs.

[0006] The present invention solves the above problem by providing a communication system comprising a domain controller connected to a first bus and a second bus, a first ECU belonging to a first network area, and a second ECU belonging to a second network area, wherein the domain controller receives a first data frame from the first bus, the first data frame including a first frame ID and first control information, generates a second data frame including a second frame ID different from the first frame ID, the first control information, and the second control information, and transmits the second data frame from the second bus.

[0007] According to the present invention, the number of available frame IDs can be increased.

[0008] Fig. 1 is a configuration diagram of a communication system according to an embodiment of the present invention. Fig. 2 is a block diagram showing the configuration of an ECU in Fig. 1. Fig. 3 is an explanatory diagram showing the data configuration of a data frame communicated in the in-vehicle network system in Fig. 1. Fig. 4 is a configuration diagram of a communication system according to another embodiment of the present invention. Fig. 5 is a configuration diagram of a communication system according to another embodiment of the present invention.

[0009] An embodiment of the present invention will now be described with reference to the drawings. In this embodiment, a communication system according to the present invention will be described using an example in which it is applied to an in-vehicle network system. As shown in Fig. 1, the communication system according to this embodiment includes a gateway 1, domain controllers (DM) 10 and 20, and battery control units (ECUs) 11 and 12. The gateway 1, the domain controllers 10 and 20, and the battery control units (ECUs) 11 and 12 are connected via a CAN.

[0010] The communication network in which the communication system according to this embodiment is provided includes a global area 100 and local areas 201 and 202. The global area 100 is a relay area used when transmitting and receiving data frames between the local areas 201 and 202, and is located above the local areas 201 and 202. The local areas 201 and 202 correspond to functional domains of a vehicle. The functional domains of a vehicle are classified into groups based on functions such as the powertrain and autonomous driving system. The domains are made up of multiple control groups separated based on the basic configuration of the vehicle.

[0011] A domain is composed of ECUs and buses, and examples of domains include a multimedia domain, an ADAS (Advanced Driver-Assistance System) domain, and a powertrain domain. An ECU belonging to the multimedia domain controls information presentation devices such as a head unit including a car navigation device. An ECU belonging to the ADAS (Advanced Driver-Assistance System) domain controls in-vehicle devices related to driving assistance control, such as cameras, radar, LIDAR (Light Detection and Ranging), and an object recognition device that performs sensor fusion processing based on the outputs of these. An ECU belonging to the powertrain domain controls vehicle drive sources such as an engine and a motor.

[0012] ECUs belonging to the same domain can transmit and receive data frames within a single local area. On the other hand, when an ECU belonging to one domain transmits and receives data frames with an ECU belonging to another domain, the data frames are transmitted and received via the gateway 1 and domain controllers 10 and 20 in the global area 100.

[0013] At least one domain controller 10, 20 is assigned to each local area 201, 202. For example, the domain controller 10 is assigned to the local area 201, and the domain controller 20 is assigned to the local area 202. The global area 100 is assigned a gateway 1 for transferring data frames between the multiple local areas 201, 202. That is, the communication network is configured with the CAN communication networks connected in a tree structure with the gateway 1 at the top, and the domain controllers 10, 20 function as hubs of the communication network. The global area 100, the local areas 201, and the local areas 202 each comprise a closed communication network. The gateway 1 and the domain controllers 10, 20 are connected to a pair of buses. If the pair of buses belongs to different areas, the ECUs connected to the pair of buses can separate the network areas. On the other hand, as shown in FIG. 1, the ECUs 11, 12 are connected to the CAN communication network by a single bus, and therefore do not separate the network areas.

[0014] The gateway 1 is an ECU connected to multiple domain controllers 10, 20 via multiple buses and relaying data frames between them. When the gateway 1 receives and buffers data frames from the domain controllers 10, 20, it transmits the data frames to the previous ECU (domain controller 10, 20) in the order in which they were received or in the transmission order based on the frame ID.

[0015] The domain controllers 10 and 20 aggregate multiple ECUs belonging to network areas and are provided in correspondence with the functional domains of the vehicle. The domain controllers 10 and 20 are ECUs that perform relay processing of data frames within local areas 201 and 202 and relay processing of data frames between the global area 100 and the local areas 201 and 202. For example, the domain controller 10 aggregates multiple ECUs 11 and 12 belonging to the local area 201 and is provided in the vehicle in correspondence with the vehicle domain.

[0016] The domain controller 10 is provided in the local area 201, and the domain controller 20 is provided in the local area 202. The domain controller 10 is connected to a bus 10a in the global area 100 and to a bus 10b in the local area 201. The domain controller 10 transfers data frames between the ECUs 11 and 12 that belong to the local area 201. When the ECUs 11 and 12 that belong to the local area 201 transmit a data frame to an ECU that belongs to another local area, the domain controller 10 receives the data frame from the bus 10b and transmits the data frame from the bus 10a to the global area 100. When the ECUs that belong to another local area transmit a data frame to the ECUs 11 and 12 that belong to the local area 201, the domain controller 10 receives the data frame from the bus 10a and transmits the data frame to the local area 201 from the bus 10b.

[0017] The domain controller 20 is connected to the bus 10 in the global area 100 and to a bus in the local area 202. The domain controller 20 transmits and receives data frames to and from the ECUs belonging to the local area 202 in the same manner as the domain controller 10.

[0018] The ECUs 11 and 12 belong to the local area 201. The ECUs 11 and 12 are configured as computers equipped with hardware and software. Although not shown in detail, the ECU 4 includes a ROM (Read Only Memory) storing a program, a CPU (Central Processing Unit) that executes the program stored in the ROM, and a RAM (Random Access Memory) that temporarily stores data generated during program execution. The ROM stores a control program for controlling the in-vehicle devices connected to each of the ECUs 11 and 12. Note that the ECUs of the gateway 1 and the domain controllers 10 and 20 may also have a configuration similar to that of the ECUs 11 and 12.

[0019] The gateway 1 and the domain controllers 10 and 20 are ECUs that belong to a global area 100. The domain controller 10 and the ECUs 11 and 12 are ECUs that belong to a local area 201. The domain controller 20 is an ECU that belongs to a local area 202. Note that the ECUs that belong to each area are not limited to the ECUs shown in FIG. 1 .

[0020] Next, the configuration of an ECU such as the domain controller 10 will be described with reference to Fig. 2. The domain controller 10 includes a communication unit 101, a data acquisition unit 102, a frame generation unit 103, and a storage unit 104 as functional blocks.

[0021] The communication unit 101 communicates with ECUs belonging to the same network area via the CAN. The communication unit 101 also communicates with other ECUs via the CAN and the gateway 1. When receiving a data frame transmitted from another ECU, the communication unit 101 checks the CAN ID of the data frame and receives the data frame having a predetermined CAN ID.

[0022] The data acquisition unit 102 acquires sensor information indicating the detection results of sensors from in-vehicle devices such as sensors connected to the ECU. The frame generation unit 103 generates control information including the sensor information based on the sensor information acquired by the data acquisition unit 102. When a control command is output to an in-vehicle device via another ECU, the frame generation unit 103 generates control information including the control command. The control information is information processed by the ECU. For example, when the control information includes vehicle speed information, the control information is processed by an ECU for controlling a powertrain or an ECU for controlling an autonomous driving system. Note that the control information may be processed not only by the ECU to which the data frame is sent, but also by the ECU from which it is sent. Then, the frame generation unit 103 generates a data frame to be transmitted by the communication unit 101 based on the generated control information. Specifically, the frame generation unit 103 sets a CAN ID depending on the type of sensor information acquired by the data acquisition unit 102. The frame generating unit 103 stores, for example, a table in which sensor information and CAN IDs are associated with each other, and sets the CAN ID based on this table.

[0023] 3 shows an example of the configuration of a data frame generated by the frame generation unit 103. The data frame includes an ID field 91 in which a CAN ID is stored and a data field 92 in which data is stored. Control information to be processed by the ECU is stored in the data field 92. In the example of FIG. 3, the CAN ID is assigned "100," and "A," "B," and "C" are stored as types of control information. Note that the data frame includes not only the CAN ID and control information, but also DLC (Date Length Code) and the like.

[0024] The storage unit 104 stores the data stored in the data frame received by the communication unit 101 .

[0025] In this embodiment, the communication protocol used in the global area 100 and the local areas 201 and 202 is the CAN protocol. Data frames communicated using the CAN protocol are not assigned identifiers indicating the sender or destination. Instead, each ECU assigns a CAN ID to each data frame before transmitting it. The receiving ECU identifies the data frame to receive from the CAN ID. The number of CAN IDs is limited to an upper limit, such as 2048. Therefore, if the entire communication system including the global area 100 and the local areas 201 and 202 is treated as a single communication area and CAN IDs are assigned, the number of frame IDs available for use in data frames cannot exceed the upper limit. In other words, the number of available frame IDs cannot be increased.

[0026] In this embodiment, in order to increase the number of usable frame IDs, frame IDs are managed individually for each network to which the domain controllers 10 and 20 are connected. The frame ID management method in this embodiment will be described below with reference to FIG. 1. In FIG. 1, the frame name of data frame 31 is "DM20_A101," and the frame name of data frame 32 is "ECU11_A201." The file names are illustrated for convenience in distinguishing between frames, and file name information is not included in the data frames.

[0027] In the example of FIG. 1 , the domain controller 20 transmits a data frame 31. The data frame 31 includes a CAN ID (ID: 100) and control information (A, B, C). The data frame 31 is communicated in the global area 100, and the destination of the data frame 31 is the DM 10. At least one of the three types of control information (A), (B), and (C) is processed by an ECU belonging to the global area 100.

[0028] In the global area 100, CAN IDs are managed so that destination ECUs corresponding to the CAN ID (ID: 100) include the DM 10. Therefore, the frame generation unit included in the domain controller 20 assigns the CAN ID (ID: 100) to the data frame 31 so that the destination ECUs of the control information (A, B, C) include the domain controller 10. Then, the domain controller 20 transmits the data frame 31 to the CAN communication network in the global area 100.

[0029] The ECU 11 also transmits a data frame 32. The data frame 32 includes a CAN ID (ID: 100) and control information (X, Y). The data frame 32 is communicated in the local areas 201 and 202, and the destination of the data frame 32 is the DM 10. One of the three types of control information (X) and (Y) is processed by an ECU (e.g., the ECU 12) that belongs to the local area 200.

[0030] Within the local area 201, CAN IDs are managed so that destination ECUs corresponding to the CAN ID (ID: 100) include the domain controller 10. Therefore, the frame generation unit included in the ECU 11 assigns the CAN ID (ID: 100) to the data frame 31 so that the destination ECUs of the control information (X, Y) include the domain controller 10. Then, the ECU 11 transmits the data frame 32 to the CAN communication network within the local area 201.

[0031] Here, the frame ID included in data frame 31 and the frame ID included in data frame 32 are the same ID (ID: 100). When the entire communication system including global area 100 and local areas 201 and 202 is treated as a single communication area and CAN IDs are managed as in the past, the same frame ID is not assigned to data frame communications between one set of ECUs and data frame communications between other sets of ECUs in the single communication area. In contrast, in this embodiment, the network in the communication system is divided at the domain controllers 10 and 20 as boundaries, and frame IDs are managed for each divided area. Therefore, the same data frame ID can be assigned to data frames communicated within global area 100 and data frames communicated within local area 201.

[0032] When the same CAN ID is assigned between different communication areas, as in the case of data frames 31 and 32, the frame ID of data frame 31 is assigned when the source and destination are multiple ECUs (domain controllers 10 and 20) belonging to the global area 100. Also, the frame ID of data frame 32 is assigned when the source and destination are multiple ECUs (domain controller 10 and ECU 11) belonging to the local area 201.

[0033] Buses 10a and 10b are connected to the domain controllers 10 serving as data frame destinations 31 and 32. The domain controller 10 receives a data frame 31 transmitted from a domain controller 20 via the bus 10a. The domain controller 10 also receives a data frame 32 transmitted from an ECU 11 via the bus 10b. Because the bus 10a is a CAN communication network within the global area 100, the data frame 31 received via the bus 10a can be identified as a data frame communicated within the global area 100. Similarly, the data frame 32 received via the bus 10b can be identified as a data frame communicated within the local area 201. The domain controller 20 can also identify the destination of the data frame from destinations predetermined in accordance with the frame ID. The frame ID (ID: 100) of the data frame 31 communicated within the global area 100 specifies, for communication management purposes, that the destination ECU is the domain controller 20. Furthermore, for purposes of communication management, the frame ID (ID: 100) of the data frame 32 communicated within the local area 201 specifies that the destination ECU is the ECU 11. Therefore, the domain controller 10 can identify the destination ECU from the fact that the data frame 31 has been received from the bus 10a and from the CAN ID assigned to the data frame 31.

[0034] As described above, the communication system according to this embodiment includes the domain controller 10 connected to the bus 10a in the global area 100 and the bus 10b in the local area 201, ECUs (such as the domain controller 20) belonging to the global area 100, and ECUs (such as the ECUs 11 and 12) belonging to the local area 201. The data frame 31 includes a CAN ID (ID: 100) and a control process (control information processed by the domain controller 20, etc.), and the data frame 32 includes a CAN ID (ID: 100) and a control process (control information processed by the ECU 11), and the CAN ID of the data frame 31 and the CAN ID of the data frame 32 are the same ID. This increases the number of available frame IDs.

[0035] The global area 100 corresponds to the "first network area" of the present invention, the local areas 201 and 202 correspond to the "first network area" of the present invention, an ECU (such as the domain controller 20) belonging to the global area 100 corresponds to the first ECU, and ECUs (such as ECUs 11 and 12) belonging to the local areas 201 and 202 correspond to the second ECU. The CAN ID corresponds to the "frame ID" of the present invention. The control information (A, B, C) corresponds to the "first control information" of the present invention, the control information (X, Y) corresponds to the "second control information" of the present invention, and the CAN ID (ID: 100) corresponds to the "first and second frame IDs" of the present invention.

[0036] Second Embodiment Next, a communication system according to a second embodiment will be described. The communication system according to the second embodiment differs from the communication system according to the first embodiment in that it adds control for changing the frame ID (CAN ID) in the domain controllers 10 and 20. Other control is the same as in the first embodiment, and the above-mentioned explanation will be used for the same configuration and control as in the first embodiment.

[0037] Fig. 4 is a block diagram of a communication system according to this embodiment. In the communication system shown in Fig. 4, the ECUs such as the gateway 1, the network area, and the CAN communication network are the same as those in the first embodiment.

[0038] In the example of FIG. 4 , the domain controller 10 receives a data frame 31 from the domain controller 20. The control information (A, B, C) stored in the data frame 31 is information to be processed by the ECU 12. Note that the control information (A, B, C) may be information to be processed by another ECU, such as the domain controller 10, and the ECU 12. The CAN ID (ID: 101) assigned to the data frame 31 is the same as the CAN ID of the data frame 32. In other words, the CAN ID (ID: 101) of the data frame 31 overlaps with the frame ID (used frame ID) used within the local area 201. If the domain controller 10 transmits a data frame including the control information (A, B, C) to the local area 201 without changing the CAN ID, a communication collision occurs with the data frame 32.

[0039] To avoid such a communication collision, the domain controller 10 changes the CAN ID included in the data frame 31 from (ID: 100) to (ID: 200). That is, the domain controller 10 assigns a CAN ID different from the CAN ID (ID: 100) to the data frame 31. The CAN ID (ID: 200) is an ID used within the local area 201, and is used when transmitting a data frame from the domain controller 10 to the ECU 12. The domain controller 10 transmits a data frame 33 including the changed CAN ID (ID: 200) and control information (A, B, C) to the local area 201 via the bus 10b.

[0040] In this manner, in this embodiment, when a data frame with the same data configuration in the data field 92 is transmitted across different communication areas (for example, when transmitting from the global area 100 to the local areas 201 and 202), the CAN ID is changed.

[0041] As described above, in the communication system according to this embodiment, the domain controller 10 receives, from the bus 10a, a data frame 31 including a CAN ID (ID: 100) and control information to be processed by the ECU 12, assigns a CAN ID (ID: 200) different from the CAN ID (ID: 100) to the data frame 33, and transmits the data frame 33 from the bus 10b. This increases the number of available frame IDs.

[0042] Furthermore, in the communication system according to this embodiment, if the CAN ID (ID: 100) overlaps with a frame ID used within the local area, the domain controller 10 changes the CAN ID (ID: 100) to a CAN ID (ID: 200) and transmits the data frame 33. This increases the number of available frame IDs.

[0043] The ECUs (ECUs 11, 12, etc.) belonging to local areas 201, 202 correspond to the "third ECU" of the present invention, the data frames 31, 33 correspond to the "third frame" of the present invention, the control information (A, B, C) corresponds to the "third control information" of the present invention, the CAN ID (ID: 100) corresponds to the "first frame ID" of the present invention, and the CAN ID (ID: 200) corresponds to the "third frame ID" of the present invention.

[0044] Third Embodiment Next, a communication system according to a third embodiment will be described. The communication system according to the third embodiment differs from the communication system according to the second embodiment in that new control information is added by the domain controllers 10 and 20 before transmitting data frames. Other control is the same as in the second embodiment, and the above-mentioned explanations will be used for the same configuration and control as in the second embodiment.

[0045] 5 is a block diagram of a communication system according to this embodiment. In the communication system shown in FIG. 5, a global area 100 includes a domain controller 30 in addition to the domain controllers 10 and 20. A local area 202 includes the domain controller 20 and an ECU 21.

[0046] In the example of FIG. 5 , the domain controller 10 receives a data frame 31 from the domain controller 20. The control information (A, B) stored in the data frame 31 is information to be processed by the ECU 12. On the other hand, the control information (C) stored in the data frame 31 is control information that is not processed by the ECUs 11 and 12 that belong to the local area 201, but is control information to be processed by another ECU that does not belong to the local area 201. The CAN ID (ID: 100) of the data frame 31 is used in the data frame 32 and overlaps with the frame ID (used frame ID) used within the local area 201. Therefore, the domain controller 10 changes the CAN ID included in the data frame 31 from (ID: 100) to (ID: 300).

[0047] Furthermore, the control information (C) is information that is not processed by an ECU belonging to the local area 201, and does not need to be transmitted within the local area 201. Therefore, the domain controller 10 stores the control information (P) in the position in the data field where the control information (C) was stored. The control information (P) is information that is processed by the ECU 12. Then, the domain controller 10 transmits a data frame 33 including the changed CAN ID (ID: 300) and the control information (A, B, P) to the local area 201 via the bus 10b.

[0048] As another example of data frame communication, the domain controller 20 receives a data frame 35 from the domain controller 30. The control information (A) stored in the data frame 35 is information to be processed by the ECU 21. Null data is stored in the data field of the data frame 35, leaving some space free. The CAN ID (ID: 200) of the data frame 35 overlaps with the frame ID (used frame ID) used within the local area 202. Therefore, the domain controller 10 changes the CAN ID included in the data frame 31 from (ID: 200) to (ID: 400).

[0049] The domain controller 10 stores the control information (Q) in the location where the null data was stored in the data field. The control information (Q) is information to be processed by the ECU 21. Then, the domain controller 20 transmits the data frame 36 including the changed CAN ID (ID: 400) and the control information (A, Q) to the local area 202.

[0050] In this embodiment, when a data frame with the same data structure in the data field 92 is transmitted across different communication areas (for example, when transmitting from the global area 100 to the local area 200), only the necessary information (signal) is extracted and transmitted as a separate data frame.

[0051] As described above, this embodiment includes the domain controller 10 connected to the bus 10a in the global area 100 and the bus 10b in the local area 201, ECUs (such as the domain controller 20) belonging to the global area 100, and ECUs (such as the ECUs 11 and 12) belonging to the local area 201. The domain controller 10 receives, from the bus 10a, a data frame 31 including a CAN ID (ID: 100) and control information (A, B) to be processed by the ECU 12, generates a data frame 34 including a CAN ID (ID: 300) different from the CAN ID (ID: 100), the control information (A, B), and the control information (P), and transmits the data frame 34 from the bus 10b. This increases the number of available frame IDs.

[0052] In this embodiment, when the data frame 31 includes control information (C) to be processed by an ECU other than the ECUs 11 and 12, the domain controller 10 changes the control information (C) to control information (P) and generates the data frame 34. This increases the number of available frame IDs.

[0053] Furthermore, in this embodiment, if the CAN ID (ID: 100) overlaps with a frame ID used within the local area 201, the domain controller 10 changes the CAN ID (ID: 100) to a CAN ID (ID: 300) and generates the data frame 34. This increases the number of available frame IDs.

[0054] Note that the ECUs (ECUs 11, 12, etc.) belonging to local areas 201, 202 correspond to the second ECU, data frames 31, 35 correspond to the "first data frame" of the present invention, control information (A, B) corresponds to the "first control information" of the present invention, CAN ID (ID: 100) corresponds to the "first frame ID" of the present invention, CAN ID (ID: 300, 400) corresponds to the "second frame ID" of the present invention, control information (P, Q) corresponds to the "second control information" of the present invention, control information (C) corresponds to the "third control information" of the present invention, and data frames 34, 36 correspond to the "second data frame" of the present invention.

[0055] 1 Gateway 10a, 10b Bus 10, 20, 30 Domain Controller (DM) 11, 12, 21 ECU 31 to 35 Data Frame 100 Global Area 201, 202 Local Area

Claims

1. A communications system for transmitting and receiving data in a communications network including a first network area and a second network area, comprising: a domain controller connected to a first bus in the first network area and a second bus in a second network area; a first ECU belonging to the first network area; and a second ECU belonging to the second network area, wherein the domain controller receives a first data frame from the first bus, the first data frame including a first frame ID and first control information to be processed by the second ECU; generates a second data frame including a second frame ID different from the first frame ID, the first control information, and second control information to be processed by the second ECU; and transmits the second data frame from the second bus.

2. A communication system according to claim 1, wherein, when the first data frame includes third control information to be processed by an ECU other than the second ECU, the domain controller changes the third control information to the second control information and generates the second data frame.

3. A communication system according to claim 1 or 2, wherein the domain controller, when the first frame ID overlaps with a frame ID used within the second network area, changes the first frame ID to the second frame ID and generates the second data frame.

4. A communication system according to any one of claims 1 to 3, wherein the domain controller aggregates a plurality of ECUs belonging to the second network area and is provided in the vehicle corresponding to a functional domain of the vehicle.

5. A communication system as claimed in any one of claims 1 to 4, wherein the first frame ID is assigned when a plurality of ECUs belonging to the first network area are the source and destination of transmission, and the second frame ID is assigned when a plurality of ECUs belonging to the second network area are the source and destination of transmission.

6. A communications system according to any one of claims 1 to 5, wherein a frame ID assigned to a data frame communicated within the first network area or the second network area does not include destination information, and the domain controller identifies the destination of the data frame from destinations predetermined in correspondence with the frame ID.

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