Vehicle-mounted communication system and control method for vehicle-mounted communication system

Abstract

A vehicle-mounted communication system and a control method of the vehicle-mounted communication system improve the possibility of a communication frame reaching a lower control device and prevent inappropriate control from being performed in accordance with a control message included in an old communication frame when an upper control device transmits the communication frame including the control message to the lower control device via an intermediate control device. A communication frame including a control message transmitted by an upper ECU (10) is transmitted to a first lower ECU (16) via a first communication path and a second communication path. The first lower ECU (16) determines whether the transmission order of the received communication frame is the same as or older than the transmission order of a communication frame that has been received previously, based on identification information of the received communication frame. The lower ECU (16) does not perform control processing based on the control message included in the received communication frame when it is determined that the transmission order of the received communication frame is the same as or older than the transmission order of the communication frame that has been received previously.

Description

Technical Field

[0001] This disclosure relates to an in-vehicle communication system having multiple control devices and a control method for the in-vehicle communication system. Background Technology

[0002] For example, Patent Document 1 discloses a vehicle-mounted communication system. In the vehicle-mounted communication system of Patent Document 1, gateway devices that perform relay processing are connected to each other via multiple communication lines. Furthermore, when a message is sent from one gateway device to other gateway devices, each gateway device outputs the same message to multiple communication lines. A timestamp is embedded in each message. The gateway device receiving the message determines, based on the timestamp, whether the message received via the multiple communication lines is the same as a previously received message. If it is determined to be the same message, the gateway device discards the received message. On the other hand, if it is determined to be a message received for the first time, the gateway device performs necessary processing such as relay processing.

[0003] Existing technical documents Patent documents Patent Document 1: International Publication No. 2019 / 193963 Summary of the Invention

[0004] In vehicular communication systems, there are often hierarchical configurations of control devices (communication nodes) that communicate, such as upper-level control devices, intermediate-level control devices, and lower-level control devices. In such systems, the upper-level control device, in order to oversee the control operations of the lower-level control devices, sometimes sends control messages to these devices via communication frames, instructing them on the control actions to be performed. In this case, to optimize the control state based on vehicle conditions, communication frames containing control messages are repeatedly sent over time. The intermediate-level control device relays these repeatedly sent communication frames from the upper-level control device to its subordinate lower-level control devices (gateways). The lower-level control devices then perform control processing according to the control messages contained in the received communication frames.

[0005] When the aforementioned vehicle communication system is applied to systems that control critical vehicle functions, such as the drive system, steering system, or braking system, it is necessary to ensure that communication frames containing control messages reliably reach the lower-level control device. Therefore, for example, it is considered that the upper-level control device sends communication frames containing the same control message to the lower-level control device via multiple communication paths. Thus, even if a communication path fails, the lower-level control device can still receive communication frames containing control messages via the normal communication path.

[0006] However, due to factors such as path lengths of multiple communication paths, performance differences in the hardware and / or software of the relaying intermediate control device, communication load conditions of multiple communication paths, or speed differences in the communication protocols used for multiple communication paths, communication frames may not arrive at the lower control device in the order of transmission. For example, it can be considered that older communication frames sent previously arrive at the lower control device with a delay compared to newer communication frames sent later. In this case, if the lower control device performs control processing according to the older control messages contained in the older communication frames, it will be difficult to perform optimal control corresponding to the vehicle's condition, etc.

[0007] Furthermore, in the vehicle communication system described in Patent Document 1, only the similarity of the messages is determined. Therefore, the technology described in Patent Document 1 cannot solve the aforementioned problem.

[0008] Therefore, the purpose of this disclosure is to provide a vehicle communication system and a control method for the vehicle communication system, which, when the control devices for communication are configured hierarchically and the upper control device sends a communication frame containing control messages to the lower control device via the middle control device, can increase the likelihood of the communication frame reaching the lower control device and can prevent inappropriate control from being performed according to the control messages contained in the old communication frame.

[0009] To achieve the above objectives, the vehicle communication system according to this disclosure has multiple control devices, wherein, The multiple control devices include: a higher-level control device that sends communication frames containing control messages; a mid-level control device that relays the communication frames sent by the higher-level control device; and a lower-level control device that receives the communication frames relayed by the mid-level control device and performs control processing based on the control messages contained in the received communication frames. The communication frames containing control messages sent by the upper-level control device can reach the lower-level control device via at least two communication paths, and communication lines are connected between the upper-level control device, the intermediate-level control device, and the lower-level control device. Over time, the host control device repeatedly sends communication frames containing control messages to at least two communication paths. Each communication frame contains identification information that can determine the transmission order of the communication frames. The lower-level control device determines, based on the identification information of the received communication frames, whether the transmission order of the received communication frames is the same as or older than the transmission order of previously received communication frames. If it is determined that the transmission order of the received communication frames is neither the same as nor older than the transmission order of previously received communication frames, but is newer than the transmission order of previously received communication frames, it executes control processing based on the control messages contained in the received communication frames. If it is determined that the transmission order of the received communication frames is the same as or older than the transmission order of previously received communication frames, it does not execute control processing based on the control messages contained in the received communication frames.

[0010] Furthermore, the control method for the vehicle-mounted communication system disclosed herein includes a vehicle-mounted communication system with multiple control devices. In the control method for the vehicle-mounted communication system... The multiple control devices include: a higher-level control device that sends communication frames containing control messages; a mid-level control device that relays the communication frames sent by the higher-level control device; and a lower-level control device that receives the communication frames relayed by the mid-level control device and performs control processing based on the control messages contained in the received communication frames. The communication frames containing control messages sent by the upper-level control device can reach the lower-level control device via at least two communication paths, and communication lines are connected between the upper-level control device, the intermediate-level control device, and the lower-level control device. The control methods for vehicle-mounted communication systems include: As time passes, the host control device repeatedly sends communication frames containing control messages to at least two communication paths. Each communication frame contains identification information that can identify the sending order of the communication frames. The lower-level control device, based on the identification information of the received communication frames, determines whether the transmission order of the received communication frames is the same as or older than the transmission order of previously received communication frames; and If the lower-level control device determines that the transmission order of the received communication frames is neither the same as nor older than the transmission order of previously received communication frames, but newer than the transmission order of previously received communication frames, it executes control processing based on the control messages contained in the received communication frames. If it determines that the transmission order of the received communication frames is the same as or older than the transmission order of previously received communication frames, it does not execute control processing based on the control messages contained in the received communication frames.

[0011] According to the vehicle-to-everything (V2X) communication system and its control method disclosed herein, a communication line is connected between the upper-level control device, the intermediate-level control device, and the lower-level control device such that communication frames containing control messages sent by the upper-level control device can reach the lower-level control device via at least two communication paths. Therefore, even if a communication path fails, the lower-level control device can still receive communication frames containing control messages via a normal communication path. This increases the likelihood that communication frames containing control messages will reach the lower-level control device.

[0012] Furthermore, according to the vehicle-to-everything (V2X) communication system and its control method disclosed herein, the lower-level control device determines, based on the identification information of the received communication frames, whether the transmission order of the received communication frames is the same as or older than the transmission order of previously received communication frames. Then, if the lower-level control device determines that the transmission order of the received communication frames is the same as or older than the transmission order of previously received communication frames, it does not perform control processing based on the control messages contained in the received communication frames. This prevents inappropriate control from being performed based on control messages contained in communication frames older than previously received communication frames.

[0013] Furthermore, the technical features described in each of the claims, other than those of the present disclosure, become clear from the following description of the embodiments and the accompanying drawings. Attached Figure Description

[0014] Figure 1 This is a configuration diagram illustrating an example of the configuration of the vehicle communication system according to the first embodiment.

[0015] Figure 2 This is a diagram showing the first and second communication paths that represent the communication paths from the higher-level ECU to the first lower-level ECU, where a communication frame containing control messages is sent.

[0016] Figure 3 This is an illustrative diagram used to explain the problems that may occur when a communication frame containing control messages is sent to the upper-level ECU and the lower-level ECU via a first communication path and a second communication path.

[0017] Figure 4 This is a flowchart illustrating the processes involved in transmitting communication frames in the host ECU of the first embodiment.

[0018] Figure 5 This is a flowchart illustrating the processes involved in receiving communication frames in the first and second lower-level ECUs of the first embodiment.

[0019] Figure 6This is a sequence diagram illustrating the effects of the processing involved in transmitting communication frames in the upper-level ECU and the processing involved in receiving communication frames in the first and second lower-level ECUs in the first embodiment.

[0020] Figure 7 This is a flowchart illustrating the processes involved in transmitting communication frames in the host ECU of the second embodiment.

[0021] Figure 8 This is a sequence diagram illustrating the effects of the processing involved in transmitting communication frames in the host ECU in the second embodiment.

[0022] Figure 9 This is a flowchart illustrating the process performed by the host ECU in the third embodiment for anomaly detection.

[0023] Figure 10 This is an explanatory diagram illustrating the anomaly detection function of the host ECU in the third embodiment.

[0024] Figure 11 This is a flowchart illustrating the processes performed by the first and second intermediate ECUs in the third embodiment for anomaly detection.

[0025] Figure 12 This is an explanatory diagram illustrating the anomaly detection function of the first and second intermediate ECUs in the third embodiment.

[0026] Figure 13 This is a configuration diagram showing the structure of the vehicle communication system in Modified Example 1.

[0027] Figure 14 This is a configuration diagram showing the configuration of the vehicle communication system in Modified Example 2. Detailed Implementation

[0028] Hereinafter, preferred embodiments of the vehicle communication system and control method of the present disclosure will be described with reference to the accompanying drawings. However, the present disclosure is not limited to the following embodiments, and various modifications described below are also included within the technical scope of the present disclosure. The various embodiments and modifications can be appropriately combined and implemented without creating technical inconsistencies. In the following description, for the same or similar configurations, descriptions are sometimes omitted by using the same reference numerals in multiple drawings. Furthermore, when only a part of the configuration is mentioned, descriptions of other parts can be applied to other parts.

[0029] (First Implementation) Figure 1 This is a configuration diagram illustrating an example of the configuration of the vehicle communication system 100 according to this embodiment. Figure 1The illustrated vehicle communication system 100 includes a master ECU 10 as a master control device, first and second intermediate ECUs 12 and 14 as first and second intermediate control devices, and first and second lower-level ECUs 16 and 18 as first and second lower-level control devices. ECU is short for Electronic Control Unit. In this embodiment, the master ECU 10, the first and second intermediate ECUs 12 and 14, and the first and second lower-level ECUs 16 and 18 are respectively mounted on a vehicle. The vehicle communication system 100 can be applied to systems used to control important functions of a vehicle, such as at least one of the vehicle's drive system, steering system, and braking system. Vehicles include passenger cars, two-wheeled motor vehicles, transport vehicles, engineering vehicles, agricultural vehicles, military vehicles, etc.

[0030] Furthermore, the composition of the vehicle communication system 100 is not limited to... Figure 1 The example shown illustrates this. For instance, the number of upper-level ECUs 10 can be two or more, rather than one. In this case, middle-level ECUs and lower-level ECUs can be configured under each upper-level ECU. Moreover, two or more upper-level ECUs 10 can be communicatively connected to each other. Furthermore, the number of middle-level ECUs 12 and 14 configured under the upper-level ECUs 10 can be one or more, rather than two. Regarding the lower-level ECUs 16 and 18, multiple lower-level ECUs can be connected to one middle-level ECU 12 or 14.

[0031] The upper-level ECU 10, the first and second intermediate ECUs 12 and 14, and the first and second lower-level ECUs 16 and 18 can each be composed of a computer equipped with a processor, memory, and storage. The processor is, for example, a CPU (Central Processing Unit), MPU (Micro Processing Unit), GPU (Graphics Processing Unit), or DFP (Data Flow Processor) that executes predetermined processes according to a program. Memory is a volatile storage medium that temporarily stores the results of the processor's operations, such as RAM (Random Access Memory). Storage is a non-volatile storage medium such as flash memory or ROM (Read-Only Memory). Various programs and data executed by the processor are stored in the storage.

[0032] Furthermore, some or all of the functions of the upper ECU 10, the first and second middle ECUs 12 and 14, and the first and second lower ECUs 16 and 18 can be implemented in hardware, such as using ASIC (Application Specific Integrated Circuit) or FPGA (Field-Programmable Gate Array), without the use of software such as programs.

[0033] The upper-level ECU 10, the first and second intermediate ECUs 12 and 14, and the first and second lower-level ECUs 16 and 18 are configured to communicate with other ECUs via communication buses 20a, 20b, 22a, 22b, 24a, 24b, and 24c. That is, the upper-level ECU 10, the first and second intermediate ECUs 12 and 14, and the first and second lower-level ECUs 16 and 18 each have a communication interface (not shown) for communicating with other ECUs.

[0034] More specifically, the upper-level ECU 10 is communicatively connected to the first intermediate ECU 12 via communication bus 20a. Additionally, the upper-level ECU 10 is communicatively connected to the second intermediate ECU 14 via communication bus 22a. The first intermediate ECU 12 is communicatively connected to the second intermediate ECU 14 via communication bus 24a. Furthermore, the first intermediate ECU 12 is communicatively connected to the first lower-level ECU 16 via communication bus 20b (equivalent to the first communication line) and communication bus 24b (equivalent to the second communication line). Similarly, the second intermediate ECU 14 is communicatively connected to the second lower-level ECU 18 via communication buses 22b and 24c, just like the first intermediate ECU 12.

[0035] The vehicle communication system 100 can use CAN (registered trademark, hereinafter the same) as the communication protocol for communication between the upper ECU 10, the first and second intermediate ECUs 12 and 14, and the first and second lower ECUs 16 and 18. CAN is short for Controller Area Network. Furthermore, the communication protocol is not limited to CAN; the vehicle communication system 100 can use various communication protocols such as Ethernet (registered trademark, hereinafter the same), LIN (Local Interconnect Network), FlexRay (registered trademark), and CAN-FD (CAN with Flexible Data Rate).

[0036] Furthermore, for example, Ethernet can be used in communication buses 20a, 20b, 22a, and 22b, and CAN can be used in communication buses 24a, 24b, and 24c. Different communication protocols can be used in different communication buses 20a, 20b, 22a, 22b, 24a, 24b, and 24c.

[0037] The upper-level ECU 10, for example, can function as a domain controller overseeing the control of the first and second intermediate ECUs 12 and 14, and the first and second lower-level ECUs 16 and 18. A domain refers to a functional unit that broadly categorizes the functions of a vehicle, such as a powertrain domain, chassis domain, advanced driver assistance domain, body domain, or cabin domain. For example, if the upper-level ECU 10 is the domain controller for the powertrain domain, the first and second lower-level ECUs 16 and 18 include various ECUs used to control the vehicle's powertrain, such as the engine ECU, motor (inverter) ECU, battery monitoring ECU, and transmission ECU. Similarly, if the upper-level ECU 10 is the domain controller for the chassis domain, the first and second lower-level ECUs 16 and 18 include various ECUs used for chassis control, such as the steering ECU, braking ECU, and suspension ECU.

[0038] Furthermore, the drive system may comprise each ECU within the powertrain domain and actuators controlled by each ECU. Additionally, the steering system and braking system may each comprise at least one ECU within the chassis domain and actuators controlled by that ECU. Moreover, the above is one example of domain division; domain division can also differ from the example described above. For instance, the chassis domain can also be divided into a steering domain and a braking domain.

[0039] Based on information obtained from sensors and other ECUs (e.g., accelerator opening, brake pedal operation, gear position, steering gear operation, vehicle speed, engine speed, motor speed, battery level, etc.), the upper-level ECU 10 repeatedly generates control messages indicating the control content to be executed for each lower-level ECU 16, 18 over time. Furthermore, whenever a control message is generated for each lower-level ECU 16, 18, the upper-level ECU 10 creates a communication frame that appends an identifier indicating the relay destination of the control message and identification information that identifies the generation order (sending order) of the control messages. The identification information can be, for example, a sequence number that changes (increases or decreases) from a constant value each time a control message is sent, or a timestamp indicating the time of transmission.

[0040] In this context, when the vehicle communication system 100 is applied to systems that control important vehicle functions, such as the vehicle's drive system, steering system, or braking system, it is necessary to ensure that communication frames containing control messages reliably reach the first and second lower-level ECUs 16 and 18. Therefore, in this embodiment, the vehicle communication system 100 is configured such that the upper-level ECU 10 sends communication frames containing control messages to the first and second lower-level ECUs 16 and 18 via two different communication paths. With this configuration, even if one communication path fails, the first and second lower-level ECUs 16 and 18 can still receive communication frames containing control messages via the other's normal communication path. As a result, the likelihood of communication frames containing control messages reaching the first and second lower-level ECUs 16 and 18 is increased. Alternatively, the vehicle communication system 100 can also be configured to send communication frames containing control messages from the upper-level ECU 10 to the first and second lower-level ECUs 16 and 18 via three or more different communication paths.

[0041] For example, in Figure 1 In the vehicle communication system 100 shown, when the upper-level ECU 10 sends a communication frame containing control messages to the first lower-level ECU 16, the upper-level ECU 10 can... Figure 2 The first communication path, indicated by the dashed line, and the second communication path, indicated by the dotted line, send communication frames to the first lower-level ECU 16. The first communication path is the path from the upper-level ECU 10 through communication bus 20a, the first intermediate ECU 12, and communication bus 20b to the first lower-level ECU 16. The second communication path is the path from the upper-level ECU 10 through communication bus 22a, the second intermediate ECU 14, communication bus 24a, the first intermediate ECU 12, and communication bus 24b to the first lower-level ECU 16. Additionally, in... Figure 1 In the vehicle communication system 100 shown, the upper ECU 10 can also send communication frames containing control messages to the second lower ECU 18 via two different communication paths.

[0042] When the upper-level ECU 10 sends a communication frame containing control messages to the first lower-level ECU 16, the upper-level ECU 10 can substantially simultaneously send communication frames to the first communication path and the second communication path. In this case, the communication frames sent by the upper-level ECU 10 to the first communication path and the communication frames sent to the second communication path are identical in terms of control messages and identification information, but their identifiers are different. This is because the communication buses that serve as relay destinations for the communication frames in the middle-level ECUs 12 and 14 are different in the first and second communication paths.

[0043] The first and second intermediate ECUs 12 and 14 relay communication frames containing control messages repeatedly sent from the upper ECU 10 to the subordinate first and second lower ECUs 16 and 18 based on the identifier attached to the communication frame. Additionally, the first and second intermediate ECUs 12 and 14 also have the function of relaying communication frames sent from the subordinate first and second lower ECUs 16 and 18 to the upper ECU 10 based on the identifier attached to the communication frame.

[0044] More specifically, the first and second intermediate ECUs 12 and 14 have a relay destination table, which represents the correspondence between the identifier attached to the communication frame and the communication bus that becomes the relay destination of the communication frame. The first and second intermediate ECUs 12 and 14 determine whether the received communication frame needs to be relayed by referring to the relay destination table. Furthermore, when relaying is determined to be necessary, the first and second intermediate ECUs 12 and 14 relay the communication frame to the communication bus identified by the relay destination table. In addition, if the communication protocol in the communication bus receiving the communication frame differs from the communication protocol in the communication bus sending the communication frame, the first and second intermediate ECUs 12 and 14 perform protocol conversion.

[0045] The first and second lower-level ECUs 16 and 18 are, for example, control ECUs that control a predetermined controlled object in the vehicle, sensor ECUs that calculate predetermined physical quantities based on detection signals detected by sensors, or drive ECUs that output drive signals to actuators to drive the actuators. The first and second lower-level ECUs 16 and 18 perform control processing such as controlling the controlled object, calculating physical quantities, and driving the actuators according to the control messages from the upper-level ECU 10.

[0046] As described above, when the upper-level ECU 10 sends communication frames containing control messages to each of the first and second lower-level ECUs 16 and 18 via two or more different communication paths, the communication frames containing control messages may not arrive at each of the first and second lower-level ECUs 16 and 18 in the order they were sent. For example, it is also considered that a previously sent communication frame containing an older control message arrives at each of the first and second lower-level ECUs 16 and 18 with a delay compared to a later sent communication frame containing a newer control message. In this case, if the first and second lower-level ECUs 16 and 18 perform control processing according to the older control message, it may lead to the problem of difficulty in performing optimal control corresponding to the vehicle's condition. Regarding this point, refer to... Figure 3 To explain in more detail. Furthermore, in Figure 3 The diagram illustrates an example of a higher-level ECU 10 sending a communication frame containing control messages to a lower-level ECU 16 via a first communication path and a second communication path.

[0047] exist Figure 3In this process, the upper-level ECU 10 simultaneously sends the first communication frame (communication frame #1) containing the first control message (control message #1) to both the first and second communication paths. Communication frame #1 sent to the first communication path is received by the first intermediate ECU 12 via communication bus 20a. The first intermediate ECU 12 relays the received communication frame #1 to communication bus 20b through relay processing S1. Thus, communication frame #1 is received by the first lower-level ECU 16. Based on the reception of communication frame #1, the first lower-level ECU 16 executes the control processing according to control message #1.

[0048] On the other hand, communication frame #1, sent to the second communication path, is received by the second intermediate ECU 14 via communication bus 22a. The second intermediate ECU 14 relays the received communication frame #1 to communication bus 24a via relay processing S2. Thus, communication frame #1 is received by the first intermediate ECU 12 via communication bus 24a. Then, the first intermediate ECU 12 relays the received communication frame #1 to communication bus 24b via relay processing S3. Thus, communication frame #1 is again received by the first lower-level ECU 16.

[0049] like Figure 3 As shown, the upper-level ECU 10, for example, based on the condition that a fixed time has elapsed since the transmission of communication frame #1, simultaneously sends a second communication frame (communication frame #2) containing a second control message (control message #2) to both the first and second communication paths. Communication frame #2, sent to the first communication path, is received by the first intermediate ECU 12 via communication bus 20a, just like communication frame #1. Then, the received communication frame #2 is relayed to communication bus 24b through the relay processing S3 of the first intermediate ECU 12 and received by the first lower-level ECU 16.

[0050] Communication frame #2 was sent after communication frame #1. Nevertheless, as... Figure 3 As shown, communication frame #1 sent via the second communication path may be received by the first lower-level ECU 16 with a delay compared to communication frame #2 sent via the first communication path. In this case, if the first lower-level ECU 16, during the execution of control processing according to control message #2 contained in communication frame #2, receives communication frame #1 with identification information different from that of communication frame #2 and executes control processing according to control message #1, optimal control will be difficult to achieve.

[0051] Figure 3The discrepancy between the transmission order of communication frames in the upper-level ECU 10 and the reception order of communication frames in the first lower-level ECU 16 may be due to factors such as differences in path lengths of multiple communication paths, performance differences in the hardware and / or software of the relaying intermediate ECUs 12 and 14, differences in the number of relay processing operations of the intermediate ECUs 12 and 14, differences in the communication load conditions of multiple communication paths, or differences in the speed of the communication protocols used by the multiple communication paths. Therefore, when the upper-level ECU 10 transmits communication frames containing control messages to each of the first and second lower-level ECUs 16 and 18 via multiple communication paths, countermeasures are required to address the discrepancy between the transmission and reception order.

[0052] Therefore, in the vehicle communication system 100 of this embodiment, the first and second lower-level ECUs 16 and 18 are respectively configured to determine, based on the identification information attached to the received communication frame, whether the transmission order of the received communication frame is the same as or older than the transmission order of previously received communication frames. Furthermore, the first and second lower-level ECUs 16 and 18 are respectively configured to execute control processing based on the control message contained in the received communication frame when it is determined that the transmission order of the received communication frame is neither the same as nor older than the transmission order of previously received communication frames, but is newer than the transmission order of previously received communication frames. On the other hand, the first and second lower-level ECUs 16 and 18 are respectively configured not to execute control processing based on the control message contained in the received communication frame when it is determined that the transmission order of the received communication frame is the same as or older than the transmission order of previously received communication frames. Thus, it is possible to prevent inappropriate control from being executed based on the control message contained in a communication frame whose transmission order is older than the previously received communication frames.

[0053] The following is for reference Figure 4 and Figure 5 The flowcharts illustrate the processes involved in transmitting communication frames in the upper-level ECU 10 of the vehicle communication system 100 according to this embodiment, and the processes involved in receiving communication frames in the first and second lower-level ECUs 16 and 18. Furthermore, the upper-level ECU 10 executes... Figure 4 The flowchart processing, execution of the first and second lower-level ECUs 16 and 18 Figure 5 The process shown in the flowchart is equivalent to executing the control method of the vehicle communication system 100 of this disclosure.

[0054] First, refer to Figure 4 The flowchart illustrates the processing involved in sending communication frames in the host ECU10. Figure 4The process shown in the flowchart can, for example, be executed separately by the upper ECU 10 for the first and second lower ECUs 16 and 18 each at predetermined intervals. The following describes an example of the upper ECU 10 performing control processing related to the transmission of communication frames for the first lower ECU 16.

[0055] In step S100, the upper-level ECU 10 obtains information (e.g., accelerator opening, brake pedal operation, gear position, steering gear operation, vehicle speed, engine speed, motor speed, battery level, etc.) from sensors and other ECUs for generating control messages. In step S110, based on the information obtained in step S100, the upper-level ECU 10 generates a control message instructing the first lower-level ECU 16 to execute control content.

[0056] In step S120, the host ECU 10 creates a communication frame that appends an identifier indicating the relay destination of the control message generated in step S110 and identification information that can identify the generation order (transmission order) of the control message. As described above, the identification information changes in a manner that can identify the transmission order each time a communication frame (control message) is transmitted.

[0057] In step S130, the host ECU 10 determines whether the transmission period for the current communication frame has arrived based on whether a fixed time has elapsed since the previous communication frame was sent. If it is determined that the transmission period for the current communication frame has arrived, the host ECU 10 proceeds to step S140. On the other hand, if it is determined that the transmission period for the current communication frame has not arrived, the host ECU 10 repeatedly performs the process in step S130 until the transmission period arrives.

[0058] In step S140, the upper-level ECU 10 sends the communication frame created in step S120 to the lower-level ECU 16 simultaneously via the first communication path and the second communication path. Furthermore, the communication frames sent simultaneously via the first communication path and the second communication path contain the same control message and the same identification information.

[0059] Next, refer to Figure 5 The flowchart illustrates the processing involved in receiving communication frames in the first and second lower-level ECUs 16 and 18. Figure 5 The processes shown in the flowchart are executed, for example, in each of the first and second lower-level ECUs 16 and 18, every predetermined cycle. The following describes an example of the processes involved in the first lower-level ECU 16 receiving a communication frame.

[0060] In step S200, the first lower-level ECU 16 receives communication frames containing control messages via communication buses 20b and 24b. In step S210, the first lower-level ECU 16 determines the transmission order of the received communication frames based on the identification information of the received communication frames. More specifically, in step S230 (described later), the first lower-level ECU 16 saves the identification information of the latest communication frame among the communication frames containing received control messages. In step S210, the first lower-level ECU 16 determines, based on the saved identification information and the identification information of the received communication frames, whether the transmission order of the received communication frames is the same as or older than the transmission order of the already received communication frames.

[0061] In step S220, the first lower-level ECU 16 performs branch processing based on the determination result in step S210. That is, if the determination result in step S210 indicates that the transmission order of the received communication frames is neither the same as nor older than the transmission order of the already received communication frames, but is newer than the transmission order of the already received communication frames, then proceed to step S230. On the other hand, if the determination result in step S210 indicates that the transmission order of the received communication frames is the same as or older than the transmission order of the already received communication frames, then proceed to step S250.

[0062] In step S230, the first lower-level ECU 16 saves the identification information of the communication frame received in step S200 to its memory. If saved identification information already exists, the first lower-level ECU 16 updates the saved identification information to the new identification information by overwriting or similar means. Thus, the saved or updated identification information represents the identification information of the latest-sent communication frame in the communication frames received by the first lower-level ECU 16. In step S240, the first lower-level ECU 16 performs control processing according to the control message of the received communication frame. Afterwards, the first lower-level ECU 16 terminates. Figure 5 The process is shown in the flowchart.

[0063] If the processing in step S250 is performed, the transmission order of the communication frames received in step S200 is the same as or older than the transmission order of the previously received communication frames. Therefore, in step S250, the first lower-level ECU 16 does not perform control processing according to the control message of the communication frame, and discards the received communication frame. Afterwards, the first lower-level ECU 16 terminates. Figure 5 The process is shown in the flowchart.

[0064] Reference Figure 6 The sequence diagram illustrates the effects of the processing involved in transmitting communication frames in the upper-level ECU 10 and the processing involved in receiving communication frames in the first and second lower-level ECUs 16 and 18. Furthermore, in Figure 6The example shown is an example of the upper ECU 10 sending a communication frame containing control messages to the first lower ECU 16 via a first communication path and a second communication path.

[0065] like Figure 6 As shown, the upper-level ECU 10 sends the first communication frame (communication frame #1) containing the first control message (control message #1) to both the first and second communication paths simultaneously. Communication frame #1 sent to the first communication path is received by the first intermediate ECU 12 via the communication bus 20a. Then, the received communication frame #1 is relayed to the communication bus 20b through the relay processing S1 of the first intermediate ECU 12 and received by the first lower-level ECU 16. Based on the reception of communication frame #1, the first lower-level ECU 16 executes the control processing according to control message #1.

[0066] On the other hand, communication frame #1, sent to the second communication path, is received by the second intermediate ECU 14 via communication bus 22a. The second intermediate ECU 14 relays the received communication frame #1 to communication bus 24a via relay processing S2. Thus, communication frame #1 is received by the first intermediate ECU 12 via communication bus 24a. The first intermediate ECU 12 relays the received communication frame #1 to communication bus 24b via relay processing S3. Therefore, communication frame #1 sent to the second communication path is also received by the first lower-level ECU 16.

[0067] like Figure 6 As shown, the upper-level ECU 10, based on the fact that a fixed time has elapsed since the transmission of communication frame #1, simultaneously sends a second communication frame (communication frame #2) containing a second control message (control message #2) to both the first and second communication paths. Communication frame #2, sent to the first communication path, is received by the first intermediate ECU 12 via communication bus 20a, just like communication frame #1. Then, the received communication frame #2 is relayed to communication bus 24b through the relay processing S3 of the first intermediate ECU 12 and received by the first lower-level ECU 16. The first lower-level ECU 16 executes control processing according to control message #2 based on the receipt of communication frame #2.

[0068] Here, as Figure 6As shown, imagine a scenario where the first lower-level ECU 16 receives communication frame #2 via the first communication path, and then receives communication frame #1 via the second communication path. In the vehicle communication system 100 of this embodiment, the first lower-level ECU 16, based on the identification information of communication frame #1, determines whether the transmission order of communication frame #1 is the same as or older than the transmission order of the already received communication frame #2. The identification information of communication frame #1 indicates a transmission order older than the identification information of communication frame #2. Therefore, the first lower-level ECU 16 does not execute the control processing according to the control message of communication frame #1, and discards the received communication frame #1.

[0069] Thus, in the vehicle communication system 100 of this embodiment, the first lower-level ECU 16, based on the identification information of the received communication frames, determines that, except in cases where the transmission order of the received communication frames is the same as the transmission order of previously received communication frames, it will not perform control processing based on the control messages of the received communication frames if it determines that the received communication frames are older. Therefore, the vehicle communication system 100 of this embodiment can avoid unnecessary processing based on control messages of communication frames with the same transmission order. Furthermore, the vehicle communication system 100 of this embodiment can prevent inappropriate control from being performed based on control messages of communication frames older than those already received.

[0070] (Second Implementation) Next, the vehicle communication system 100 of the second embodiment of this disclosure will be described with reference to the accompanying drawings. Furthermore, the vehicle communication system 100 of this embodiment can be configured in the same way as the vehicle communication system 100 of the first embodiment. Therefore, descriptions related to configuration are omitted.

[0071] In the vehicle communication system 100 of the first embodiment, for example, when the upper ECU 10 sends a communication frame containing control messages to the first lower ECU 16, the upper ECU 10 substantially simultaneously sends... Figure 2 The first and second communication paths shown transmit communication frames.

[0072] In the vehicle communication system 100 of this embodiment, the upper-level ECU 10 is configured to send communication frames containing control messages to the first lower-level ECU 16 and the second lower-level ECU 18, respectively, via one of two or more communication paths that are switched in a predetermined order according to the transmission of the communication frames.

[0073] Thus, in the vehicle communication system 100 of this embodiment, the communication path for transmitting communication frames is switched whenever a communication frame is transmitted. Therefore, for example, even if one of the two or more communication paths connected to the first lower-level ECU 16 malfunctions, the communication frame containing the control message can still reach the first lower-level ECU 16, which is the destination, via the normal communication path. Therefore, similar to the first embodiment, the likelihood of the communication frame containing the control message reaching the first and second lower-level ECUs 16 and 18 can be increased. Furthermore, if a communication path malfunctions, the first and second lower-level ECUs 16 and 18 cannot receive communication frames from that path. Therefore, each of the first and second lower-level ECUs 16 and 18 can only obtain control messages after the control message intervals of the unreceiveable communication frames have been removed. However, even in this case, each of the first and second lower-level ECUs 16 and 18 can continue control processing based on the obtained control messages.

[0074] Furthermore, in the vehicle communication system 100 according to this embodiment, communication frames containing control messages are transmitted via a switched communication path in two or more communication paths. Therefore, compared to the case where communication frames containing control messages are transmitted via multiple communication paths at the same time, the communication load of each communication bus can be reduced.

[0075] The following is for reference Figure 7 and Figure 8 This describes the communication frame transmission processing performed by the host ECU 10 of the vehicle communication system 100 in this embodiment. Figure 7 This is a flowchart illustrating the process of transmitting communication frames in the host ECU10. Additionally, regarding... Figure 7 The following description illustrates an example of how the upper ECU 10 performs processing related to the transmission of communication frames on the first lower ECU 16. Figure 8 This is a sequence diagram illustrating an example of the upper-level ECU 10 sending a communication frame containing control messages to the first lower-level ECU 16 via a first communication path and a second communication path. Furthermore, the processing involved in receiving the communication frames executed by the first and second lower-level ECUs 16 and 18 of the vehicle communication system 100 in this embodiment is the same as in the first embodiment, and therefore, its description is omitted.

[0076] Figure 7 The processing of steps S100~S120 and S130 in the flowchart and Figure 4 The steps S100~S120 and S130 of the flowchart are the same, so the explanation is omitted.

[0077] exist Figure 7In step S125 of the flowchart, the upper-level ECU 10 switches between two or more communication paths connected to the first lower-level ECU 16 in a predetermined order to send communication frames containing control messages. Preferably, the communication paths are switched in such a way that the frequency of sending communication frames via each communication path is equal.

[0078] For example, in the communication path connected to the first lower-level ECU16, such as Figure 2 As shown, with the first and second communication paths, the host ECU 10 can alternately switch between the first and second communication paths whenever a communication frame containing control messages is sent. Figure 8 The sequence diagram illustrates an example where the upper-level ECU 10 alternately switches between the first and second communication paths whenever a communication frame containing a control message is sent. Alternatively, for example, when the communication paths connected to the first lower-level ECU 16 are the first, second, and third communication paths, the upper-level ECU 10 can switch the communication paths by repeatedly switching between the first, second, and third communication paths in sequence whenever a communication frame containing a control message is sent.

[0079] exist Figure 7 In step S135 of the flowchart, the host ECU 10 sends a communication frame containing control messages via a switched communication path. Afterwards, the host ECU 10 terminates... Figure 7 The process is shown in the flowchart.

[0080] exist Figure 8 In this process, the upper-level ECU 10 sends a first communication frame (communication frame #1) containing the first control message (control message #1) to the first communication path. Communication frame #1 sent to the first communication path is received by the first intermediate ECU 12 via the communication bus 20a. Then, the received communication frame #1 is relayed to the communication bus 20b through the relay processing S11 of the first intermediate ECU 12, and received by the first lower-level ECU 16. Based on the reception of communication frame #1, the first lower-level ECU 16 executes the control processing according to control message #1.

[0081] like Figure 8As shown, the upper ECU 10, based on the fact that a fixed time has elapsed since the transmission of communication frame #1, sends a second communication frame (communication frame #2) containing a second control message (control message #2) to the second communication path. Communication frame #2 sent to the second communication path is received by the second intermediate ECU 14 via communication bus 22a. The received communication frame #2 is relayed to communication bus 24a through the relay processing S12 of the second intermediate ECU 14 and received by the first intermediate ECU 12. Furthermore, communication frame #2 is relayed to communication bus 24b through the relay processing S13 of the first intermediate ECU 12 and received by the first lower ECU 16. The first lower ECU 16, based on the receipt of communication frame #2, executes control processing according to control message #2.

[0082] Based on the fact that a fixed time has elapsed since the transmission of communication frame #2, the upper ECU 10 sends a third communication frame (communication frame #3) containing a third control message (control message #3) to the first communication path. Communication frame #3, sent to the first communication path, is received by the first lower ECU 16 via communication bus 20a, the first intermediate ECU 12, and communication bus 20b, similar to communication frame #1. Upon receiving communication frame #3, the first lower ECU 16 executes control processing according to control message #3.

[0083] Furthermore, in the example above, the upper-level ECU 10 sends communication frames containing control messages at fixed time intervals. However, the upper-level ECU 10 can also vary the transmission interval of communication frames containing control messages in the switched communication path, based on the expected time until the communication frames containing control messages arrive at the lower-level ECUs 16 and 18.

[0084] For example, in the communication path connected to the first lower-level ECU16 Figure 2 In the case of alternating switching between the first communication path and the second communication path, the time interval from sending a communication frame through the first communication path to sending a communication frame through the second communication path can be shorter than the time interval from sending a communication frame through the second communication path to sending a communication frame through the first communication path.

[0085] Compared to the first communication path, the second communication path is longer and involves more relays from intermediate ECUs 12 and 14. Therefore, it is assumed that the time it takes for a communication frame containing control messages to reach the first lower-level ECU 16 via the second communication path is longer than the time it takes to reach the first lower-level ECU 16 via the first communication path. Therefore, by making the time interval between sending a communication frame via the first communication path and sending it via the second communication path shorter than the time interval between sending a communication frame via the second communication path and sending it via the first communication path, the intervals for receiving communication frames through the first lower-level ECU 16 can be made approximately equal.

[0086] (Third Implementation) Next, the vehicle communication system 100 of the third embodiment of this disclosure will be described with reference to the accompanying drawings. Furthermore, the vehicle communication system 100 of this embodiment can be configured in the same way as the vehicle communication system 100 of the first embodiment. Therefore, descriptions related to configuration are omitted.

[0087] In the vehicle communication system 100 of this embodiment, communication frames for storage confirmation are periodically exchanged between the upper ECU 10 and the first and second intermediate ECUs 12 and 14, between the first intermediate ECU 12 and the second intermediate ECU 14, and between the first and second intermediate ECUs 12 and 14 and their respective subordinate first and second lower ECUs 16 and 18.

[0088] The upper-level ECU 10 and the first and second intermediate ECUs 12 and 14 have an anomaly detection function that determines the occurrence of anomalies in the communication path based on the reception results of communication frames used for survival confirmation. Specifically, the upper-level ECU 10 and the first and second intermediate ECUs 12 and 14 have an anomaly detection function that determines that an anomaly has occurred in the communication path containing the corresponding communication bus and ECU when a survival confirmation communication frame cannot be received from an ECU connected via the communication bus. In the event of an anomaly detection, the upper-level ECU 10 and the first and second intermediate ECUs 12 and 14 stop using the communication path determined to have an anomaly.

[0089] For example, if the host ECU 10 is unable to receive a survival confirmation communication frame from either the first or second intermediate ECUs 12 or 14, it stops using the communication path that includes one of the first or second intermediate ECUs 12 or 14. Furthermore, if the host ECU 10 generates a communication frame containing a control message that should be sent via the stopped communication path, it uses the communication path that includes the other of the first or second intermediate ECUs 12 or 14 to send the communication frame containing the control message.

[0090] Additionally, for example, if the first intermediate ECU 12 is unable to receive a survival confirmation communication frame from its subordinate first lower-level ECU 16 via either communication bus 20b or communication bus 24b, it stops using either communication bus 20b or communication bus 24b. Then, if the first intermediate ECU 12 generates a communication frame containing a control message that should be sent via either communication bus 20b or communication bus 24b that has been stopped, it uses the other communication bus 20b or communication bus 24b to send the communication frame containing the control message.

[0091] Next, we will explain in detail the communication path anomaly detection function of the host ECU10. Figure 9 This is a flowchart illustrating the processes performed by the host ECU 10 for anomaly detection. The host ECU 10 executes these processes at predetermined intervals. Figure 9 The process is shown in the flowchart.

[0092] In step S300, the host ECU 10 sends survival confirmation communication frames to the first and second intermediate ECUs 12 and 14 via communication buses 20a and 22a. By receiving these survival confirmation communication frames from the host ECU 10, the first and second intermediate ECUs 12 and 14 can confirm that they can communicate normally with the host ECU 10 via communication buses 20a and 22a. Furthermore, as described later, each of the first and second intermediate ECUs 12 and 14 also periodically sends survival confirmation communication frames to the host ECU 10 via communication buses 20a and 22a.

[0093] In step S310, the upper ECU 10 attempts to receive survival confirmation communication frames from the first and second intermediate ECUs 12 and 14 respectively. In step S320, the upper ECU 10 determines whether it received survival confirmation communication frames from all intermediate ECUs 12 and 14 in step S310. If it is determined that no intermediate ECUs 12 and 14 failed to receive survival confirmation communication frames, and survival confirmation communication frames were received from all intermediate ECUs 12 and 14, the upper ECU 10 proceeds to step S330. On the other hand, if it is determined that some intermediate ECUs 12 and 14 failed to receive survival confirmation communication frames, and survival confirmation communication frames were not received from all intermediate ECUs 12 and 14, the upper ECU 10 proceeds to step S340.

[0094] In step S330, the upper-level ECU 10 is considered capable of normally communicating with the first and second intermediate ECUs 12 and 14, respectively. For the transmission of communication frames containing control messages, it is decided to directly use the prescribed communication path. Thus, for example, when the upper-level ECU 10 sends a communication frame containing control messages to the first lower-level ECU 16, the following communication path is used: Figure 2 The first and second communication paths are shown.

[0095] On the other hand, in step S340, the upper ECU 10 considers an anomaly to have occurred in the communication path of the intermediate ECU, which contains a communication frame that cannot receive survival confirmation, and the communication bus between the intermediate ECU and the intermediate ECU, making normal communication impossible. In this case, the upper ECU 10 decides to stop using the communication path where the anomaly occurred and instead use an other communication path.

[0096] exist Figure 10 As an example, this illustrates a situation where the upper-level ECU 10 cannot receive a survival confirmation communication frame from the first intermediate ECU 12. In this case, the upper-level ECU 10 cannot receive the survival confirmation communication frame from the first intermediate ECU 12 via the communication bus 20a, and therefore considers the communication path (first communication path) including the communication bus 20a and the first intermediate ECU 12 unusable. The upper-level ECU 10 then decides to stop using the communication path (first communication path) including the communication bus 20a and the first intermediate ECU 12. In this state, for example, if a communication frame containing a control message that should be sent to the first lower-level ECU 16 via the communication path (first communication path) including the communication bus 20a and the first intermediate ECU 12 is generated, the upper-level ECU 10 sends the communication frame via the second communication path including the second intermediate ECU 14.

[0097] Next, the abnormality detection function of the communication path of the first and second intermediate ECUs 12 and 14 will be explained in detail. Figure 11 This is a flowchart illustrating the processes performed by the first and second intermediate ECUs 12 and 14 for anomaly detection. The first and second intermediate ECUs 12 and 14 execute each at predetermined intervals. Figure 11 The process is shown in the flowchart. The following steps are performed on the first intermediate ECU12. Figure 11 The flowchart illustrates an example of the processing.

[0098] In step S400, the first intermediate ECU 12 sends a survival confirmation communication frame via all connected communication buses 20a, 20b, 24a, and 24b. Specifically, the first intermediate ECU 12 sends the survival confirmation communication frame to the upper-level ECU 10, the second intermediate ECU 14, and the subordinate first lower-level ECU 16 via communication buses 20a, 24a, 20b, and 24b, respectively.

[0099] The second intermediate ECU 14, by receiving survival confirmation communication frames from the first intermediate ECU 12, can confirm that normal communication with the first intermediate ECU 12 via communication bus 24a is possible. Furthermore, the second intermediate ECU 14 also periodically sends survival confirmation communication frames to the first intermediate ECU 12 via communication bus 24a. Similarly, the first lower-level ECU 16, by receiving survival confirmation communication frames from the first intermediate ECU 12 via communication buses 20b and 24b, can confirm that normal communication with the first intermediate ECU 12 via communication buses 20b and 24b is possible. Then, the first lower-level ECU 16 also periodically sends survival confirmation communication frames to the first intermediate ECU 12 via communication buses 20b and 24b.

[0100] In step S410, the first intermediate ECU 12 attempts to receive survival confirmation communication frames from the upper ECU 10, the second intermediate ECU 14, and the first lower ECU 16, respectively. In step S420, the first intermediate ECU 12 determines whether it has received survival confirmation communication frames from the first lower ECU 16 via all communication buses 20b and 24b. If the first intermediate ECU 12 determines that it has received survival confirmation communication frames from the first lower ECU 16 via all communication buses 20b and 24b between itself and the first lower ECU 16, it proceeds to step S430. On the other hand, if the first intermediate ECU 12 determines that there are communication buses 20b and 24b between itself and the first lower ECU 16 where survival confirmation communication frames cannot be received, and thus fails to receive survival confirmation communication frames from the first lower ECU 16 via all communication buses 20b and 24b, it proceeds to step S440.

[0101] In step S430, the first intermediate ECU 12 is considered capable of communicating normally with the first lower-level ECU 16 via communication buses 20b and 24b respectively. For the transmission of communication frames containing control messages, it is decided to directly use the prescribed communication path. Therefore, when the first intermediate ECU 12 sends a communication frame containing control messages to the first lower-level ECU 16, both communication buses 20b and 24b are used.

[0102] On the other hand, in step S440, the first intermediate ECU 12 is deemed to have encountered an anomaly in the communication path of the communication bus, which includes a communication bus that cannot receive communication frames for survival confirmation, and is unable to communicate normally with the first lower-level ECU 16 via the corresponding communication bus. In this case, the first intermediate ECU 12 decides to stop using the communication bus that has encountered the anomaly and instead use another communication bus.

[0103] exist Figure 12As an example, this example illustrates a situation where the first intermediate ECU 12 cannot receive a survival confirmation communication frame from the first lower-level ECU 16 via communication bus 20b. In this case, the first intermediate ECU 12 cannot receive the survival confirmation communication frame from the first lower-level ECU 16 via communication bus 20b, and is therefore considered unable to use communication bus 20b (the first communication line). Then, the first intermediate ECU 12 decides to stop using communication bus 20b. In this state, if the first intermediate ECU 12 receives a communication frame containing control messages from the upper-level ECU 10 via communication bus 20a, it changes the relay destination of that communication frame to communication bus 24b instead of communication bus 20b. That is, the first intermediate ECU 12 instead uses communication bus 24b to send communication frames containing control messages. Thus, the first lower-level ECU 16 can receive communication frames containing control messages via communication bus 24b.

[0104] In addition, Figure 11 In the flowchart, the first and second intermediate ECUs 12 and 14 respectively determine the occurrence of abnormalities in the communication buses 20b, 22b, 24b, and 24c between themselves and their subordinate first and second lower-level ECUs 16 and 18. In addition, the first and second intermediate ECUs 12 and 14 can also determine that the communication bus 24a connecting them has malfunctioned. Furthermore, when the first and second intermediate ECUs 12 and 14 detect an abnormality in the communication bus 24a, they preferably notify the upper-level ECU 10. Thus, when the upper-level ECU 10 sends a communication frame containing control messages to the first lower-level ECU 16, it can determine that a second communication path that uses the communication bus 24a as part of the path cannot be used. Therefore, the upper-level ECU 10 can decide to stop using the second communication path and use the first communication path instead.

[0105] Furthermore, the vehicle communication system 100 of the third embodiment described above can be applied not only to the vehicle communication systems 100 of the first and second embodiments, but also to communication methods different from those of the vehicle communication systems 100 of the first and second embodiments.

[0106] For example, when the upper-level ECU 10 sends a communication frame containing control messages to the first lower-level ECU 16, the upper-level ECU 10 may also use the first communication path to send the communication frame containing control messages while it is detected that communication is possible through the first communication path. Furthermore, if an anomaly is detected in the first communication path, the upper-level ECU 10 may also use the second communication path to send the communication frame containing control messages.

[0107] (Variation example) The preferred embodiments of this disclosure have been described above, but this disclosure is not limited to any of the above embodiments and can be implemented in various ways without departing from the spirit of this disclosure.

[0108] (Variation Example 1) In the vehicle communication system 100 of the first embodiment, for example, as a communication path from the upper ECU 10 to the first lower ECU 16, a first communication path including communication bus 20a, first middle ECU 12 and communication bus 20b and a second communication path including communication bus 22a, second middle ECU 14, communication bus 24a, first middle ECU 12 and communication bus 24b are used.

[0109] However, the multiple communication paths from the upper ECU 10 to the first and second lower ECUs 16 and 18 are not limited to the communication paths described above. Depending on the configuration of the communication bus, the upper ECU 10 can send communication frames to the first and second lower ECUs 16 and 18 via various communication paths.

[0110] For example, such as Figure 13 As shown, communication buses 24b and 24c can also be replaced by communication bus 26a between the first intermediate ECU 12 and the second lower ECU 18, and communication bus 26b between the second intermediate ECU 14 and the first lower ECU 16. In this case, the first communication path from the upper ECU 10 to the first lower ECU 16 can be set as a path from the upper ECU 10 to the first lower ECU 16 via communication bus 20a, the first intermediate ECU 12, and communication bus 20b. The second communication path can be set as a path to the first lower ECU 16 via communication bus 22a, the second intermediate ECU 14, and communication bus 26b.

[0111] Furthermore, in Figure 13 In the configuration shown, a third communication path can also be set between the upper ECU 10 and the first lower ECU 16. For example, the third communication path can be set as a path from the upper ECU 10 to the first lower ECU 16 via communication bus 22a, the second middle ECU 14, communication bus 24a, the first middle ECU 12, and communication bus 20b.

[0112] (Variation Example 2) Furthermore, other examples of communication bus configurations include... Figure 14 As shown, it can also be used for Figure 1The configuration includes a communication bus 28a between the upper ECU 10 and the first intermediate ECU 12, and a communication bus 28b between the upper ECU 10 and the second intermediate ECU 14. In this case, for example, more than four communication paths can also be set between the upper ECU 10 and the first lower ECU 16.

[0113] (Variation Example 3) In the various embodiments and modifications described above, the upper-level ECU 10 is configured to send communication frames containing control messages to all lower-level ECUs 16 and 18 via two or more communication paths. However, the upper-level ECU 10 may not necessarily send communication frames containing control messages to all lower-level ECUs 16 and 18 via two or more communication paths. For example, the upper-level ECU 10 preferably sends communication frames containing control messages to lower-level ECUs performing control processes of relatively high importance via two or more communication paths. On the other hand, the upper-level ECU 10 may also send communication frames containing control messages to lower-level ECUs performing control processes of relatively low importance via only one communication path.

[0114] In addition to, or instead of, the host ECU10 can also select whether to send the control message via two or more communication paths or only via one communication path, depending on the importance of the control message contained in the communication frame.

[0115] (Variation Example 4) In the above-described embodiments and modifications, the vehicle communication systems 100, 100A, and 100B are configured as three layers: a higher-level ECU 10, first and second intermediate ECUs 12 and 14, and first and second lower-level ECUs 16 and 18. However, the vehicle communication system of this disclosure can also be configured as four or more layers.

[0116] (Variation Example 5) The systems and methods described in this disclosure can also be implemented by a special-purpose computer comprising a processor programmed to perform one or more functions embodied in a computer program. The systems and methods described in this disclosure can also be implemented using special-purpose hardware logic circuits. The systems and methods described in this disclosure can also be implemented by one or more special-purpose computers comprising a processor executing a computer program and a combination of one or more hardware logic circuits. For example, some or all of the functions possessed by the upper-level ECU 10, the first and second intermediate ECUs 12, 14, and the first and second lower-level ECUs 16, 18 can also be implemented as hardware. Implementing a function as hardware includes using one or more ICs. Some or all of the functions possessed by the upper-level ECU 10, the first and second intermediate ECUs 12, 14, and the first and second lower-level ECUs 16, 18 can also be implemented using any one of a system-on-a-chip (SoC), an integrated circuit (IC), and a field-programmable gate array (FPGA). The concept of IC also includes ASIC (Application Specific Integrated Circuit). Furthermore, computer programs, as instructions executed by a computer, can be stored on a computer-readable, non-transitory tangible storage medium. HDDs (Hard-disk Drives), SSDs (Solid State Drives), flash memory, and the like can be used as the program recording medium. Additionally, the scope of this disclosure also includes non-transitory physical recording media such as programs used to enable the computer to function as the upper-level ECU 10, the first and second intermediate ECUs 12 and 14, and the first and second lower-level ECUs 16 and 18, and semiconductor memories storing these programs.

[0117] (The disclosure of technical ideas) Finally, this specification discloses several technical ideas described in the following list of items. Some items can be described in a multiple dependent format, alternating references to multiple preceding items. Furthermore, some items can be described in a multiple multiple dependent format, referencing multiple items that include other items in the multiple dependent format. Items described in the multiple dependent format and the multiple multiple dependent format define several technical ideas. Moreover, the several technical ideas described in the following list of items are also applicable to control methods for vehicle communication systems.

[0118] (Technical Idea 1) A vehicle-mounted communication system, comprising multiple control devices, characterized in that, The plurality of control devices include: a higher-level control device for transmitting communication frames containing control messages; a mid-level control device for relaying the communication frames transmitted by the higher-level control device; and a lower-level control device for receiving the communication frames relayed by the mid-level control device and performing control processing based on the control messages contained in the received communication frames. A communication line is connected between the upper-level control device, the middle-level control device, and the lower-level control device so that the communication frame containing the control message sent by the upper-level control device can reach the lower-level control device via at least two communication paths. As time passes, the host control device repeatedly sends communication frames containing the control message to at least two of the communication paths. Each communication frame contains identification information that can identify the transmission order of the communication frames. The lower-level control device determines, based on the identification information of the received communication frames, whether the transmission order of the received communication frames is the same as or older than the transmission order of previously received communication frames. If it is determined that the transmission order of the received communication frames is neither the same as nor older than the transmission order of previously received communication frames, but is newer than the transmission order of previously received communication frames, it performs control processing based on the control message contained in the received communication frames. If it is determined that the transmission order of the received communication frames is the same as or older than the transmission order of previously received communication frames, it does not perform control processing based on the control message contained in the received communication frames.

[0119] (Technical Idea 2) According to the vehicle communication system described in technical concept 1, wherein, The upper-level control device sends multiple communication frames containing identification information indicating the same transmission order to the lower-level control device at the same time via at least two communication paths.

[0120] (Technical Idea 3) According to the vehicle communication system described in technical concept 1, wherein, The upper-level control device sends the repeatedly transmitted communication frames to the lower-level control device via one of the communication paths, which is switched in a predetermined order each time the communication frame is transmitted.

[0121] (Technical Idea 4) According to the vehicle communication system described in technical concept 2 or 3, wherein, The host control device sends the communication frames at fixed time intervals.

[0122] (Technical Idea 5) According to the vehicle communication system described in technical concept 3, wherein, The upper-level control device changes the transmission interval of the repeatedly transmitted communication frames on the switched communication path according to the assumed time before the communication frame arrives at the lower-level control device.

[0123] (Technical Idea 6) According to any one of technical concepts 1 to 5, in the vehicle communication system, wherein, The mid-position control device includes at least a first mid-position control device and a second mid-position control device. At least two of the communication paths include a first communication path relayed by the first intermediate control device and a second communication path relayed by the second intermediate control device.

[0124] (Technical Idea 7) According to the vehicle communication system described in technical concept 6, wherein, When sending the communication frame containing the control message to the lower control device under the first intermediate control device, the first communication path is the path from the upper control device to the lower control device via the first intermediate control device, and the second communication path is the path from the upper control device to the first intermediate control device via the second intermediate control device, and then from the first intermediate control device to the lower control device.

[0125] (Technical Idea 8) According to the vehicle communication system described in technical concept 7, wherein, A first communication line for the first communication path and a second communication line for the second communication path are provided between the first intermediate control device and the subordinate lower control device.

[0126] (Technical Idea 9) According to any one of technical concepts 6 to 8, in the vehicle communication system, wherein, The upper-level control device periodically receives survival confirmation communication frames from the first intermediate control device and the second intermediate control device. If the upper-level control device is unable to receive the survival confirmation communication frame from either the first or the second intermediate control device, it stops using the communication path of the intermediate control device that includes either the first or the second intermediate control device, and uses the communication path of the other intermediate control device to send the communication frame containing the control message.

[0127] (Technical Idea 10) According to the vehicle communication system described in Technical Concept 8, wherein, The first intermediate control device periodically receives survival confirmation communication frames from the subordinate lower control device via the first communication line and the second communication line. If the first intermediate control device is unable to receive the survival confirmation communication frame from the lower control device on either the first or the second communication line, it shall stop using one of the first and the second communication lines and use the other of the first and the second communication lines to send the communication frame containing the control message.

[0128] (Technical Idea 11) According to any one of technical concepts 1 to 3, in the vehicle communication system, wherein, The vehicle communication system is applied to at least one of the vehicle's drive system, steering system, and braking system.

[0129] Furthermore, in the second embodiment described above, the following technical concept 12 is disclosed.

[0130] (Technical Idea 12) A vehicle-mounted communication system includes multiple control devices, wherein, The plurality of control devices include: a higher-level control device for transmitting communication frames containing control messages; a mid-level control device for relaying the communication frames transmitted by the higher-level control device; and a lower-level control device for receiving the communication frames relayed by the mid-level control device and performing control processing based on the control messages contained in the received communication frames. A communication line is connected between the upper-level control device, the middle-level control device, and the lower-level control device so that the communication frame containing the control message sent by the upper-level control device can reach the lower-level control device via at least two communication paths. As time passes, the host control device repeatedly sends communication frames containing the control messages. The upper-level control device sends the repeatedly transmitted communication frames to the lower-level control device via one of the communication paths, which is switched in a predetermined order each time the communication frame is transmitted.

[0131] In addition, the following technical concepts 13 and 14 are disclosed in the third embodiment described above.

[0132] (Technical Idea 13) A vehicle-mounted communication system includes multiple control devices, wherein, The plurality of control devices include: a higher-level control device for transmitting communication frames containing control messages; a mid-level control device for relaying the communication frames transmitted by the higher-level control device; and a lower-level control device for receiving the communication frames relayed by the mid-level control device and performing control processing based on the control messages contained in the received communication frames. A communication line is connected between the upper-level control device, the middle-level control device, and the lower-level control device so that the communication frame containing the control message sent by the upper-level control device can reach the lower-level control device via at least two communication paths. As time passes, the host control device repeatedly sends communication frames containing the control messages. The mid-position control device includes at least a first mid-position control device and a second mid-position control device. The upper-level control device periodically receives survival confirmation communication frames from the first and second intermediate-level control devices. If the upper-level control device is unable to receive the survival confirmation communication frame from either the first or the second intermediate control device, it stops using the communication path of the intermediate control device that includes either the first or the second intermediate control device, and uses the communication path of the intermediate control device that includes the other intermediate control device to send the communication frame containing the control message.

[0133] (Technical Idea 14) A vehicle-mounted communication system includes multiple control devices, wherein, The plurality of control devices include: a higher-level control device for transmitting communication frames containing control messages; a mid-level control device for relaying the communication frames transmitted by the higher-level control device; and a lower-level control device for receiving the communication frames relayed by the mid-level control device and performing control processing based on the control messages contained in the received communication frames. A communication line is connected between the upper-level control device, the middle-level control device, and the lower-level control device so that the communication frame containing the control message sent by the upper-level control device can reach the lower-level control device via at least two communication paths. The communication line includes a first communication line and a second communication line disposed between the intermediate control device and the subordinate lower control device. The host control device repeatedly sends the communication frame containing the control message over time. The intermediate control device periodically receives survival confirmation communication frames from the subordinate lower control devices via the first communication line and the second communication line. If the intermediate control device is unable to receive the survival confirmation communication frame from the lower control device on either the first or the second communication line, it shall stop using one of the first and the second communication lines and use the other of the first and the second communication lines to send the communication frame containing the control message.

Claims

1. A vehicle-mounted communication system comprising multiple control devices, characterized in that, The plurality of control devices include: a higher-level control device for transmitting communication frames containing control messages; a mid-level control device for relaying the communication frames transmitted by the higher-level control device; and a lower-level control device for receiving the communication frames relayed by the mid-level control device and performing control processing based on the control messages contained in the received communication frames. A communication line is connected between the upper-level control device, the middle-level control device, and the lower-level control device so that the communication frame containing the control message sent by the upper-level control device can reach the lower-level control device via at least two communication paths. As time passes, the host control device repeatedly sends communication frames containing the control message to at least two of the communication paths. Each communication frame contains identification information that can identify the transmission order of the communication frames. The lower-level control device determines, based on the identification information of the received communication frames, whether the transmission order of the received communication frames is the same as or older than the transmission order of previously received communication frames. If it is determined that the transmission order of the received communication frames is neither the same as nor older than the transmission order of previously received communication frames, but is newer than the transmission order of previously received communication frames, it performs control processing based on the control message contained in the received communication frames. If it is determined that the transmission order of the received communication frames is the same as or older than the transmission order of previously received communication frames, it does not perform control processing based on the control message contained in the received communication frames.

2. The vehicle-mounted communication system according to claim 1, characterized in that, The upper-level control device sends multiple communication frames containing identification information indicating the same transmission order to the lower-level control device at the same time via at least two communication paths.

3. The vehicle-mounted communication system according to claim 1, characterized in that, The upper-level control device sends the repeatedly transmitted communication frames to the lower-level control device via one of the communication paths, which is switched in a predetermined order each time the communication frame is transmitted.

4. The vehicle-mounted communication system according to claim 2 or 3, characterized in that, The host control device sends the communication frames at fixed time intervals.

5. The vehicle-mounted communication system according to claim 3, characterized in that, The upper-level control device changes the transmission interval of the repeatedly transmitted communication frames on the switched communication path according to the assumed time before the communication frame arrives at the lower-level control device.

6. The vehicle-mounted communication system according to any one of claims 1 to 3, characterized in that, The mid-position control device includes at least a first mid-position control device and a second mid-position control device. At least two of the communication paths include a first communication path relayed by the first intermediate control device and a second communication path relayed by the second intermediate control device.

7. The vehicle-mounted communication system according to claim 6, characterized in that, When sending the communication frame containing the control message to the lower control device under the first intermediate control device, the first communication path is the path from the upper control device to the lower control device via the first intermediate control device, and the second communication path is the path from the upper control device to the first intermediate control device via the second intermediate control device, and then from the first intermediate control device to the lower control device.

8. The vehicle-mounted communication system according to claim 7, characterized in that, A first communication line for the first communication path and a second communication line for the second communication path are provided between the first intermediate control device and the subordinate lower control device.

9. The vehicle-mounted communication system according to claim 6, characterized in that, The upper-level control device periodically receives survival confirmation communication frames from the first intermediate control device and the second intermediate control device. If the upper-level control device is unable to receive the survival confirmation communication frame from either the first or the second intermediate control device, it stops using the communication path of the intermediate control device that includes either the first or the second intermediate control device, and uses the communication path of the other intermediate control device to send the communication frame containing the control message.

10. The vehicle-mounted communication system according to claim 8, characterized in that, The first intermediate control device periodically receives survival confirmation communication frames from the subordinate lower control device via the first communication line and the second communication line. If the first intermediate control device is unable to receive the survival confirmation communication frame from the lower control device on either the first or the second communication line, it shall stop using one of the first and the second communication lines and use the other of the first and the second communication lines to send the communication frame containing the control message.

11. The vehicle-mounted communication system according to any one of claims 1 to 3, characterized in that, The vehicle communication system is applied to at least one of the vehicle's drive system, steering system, and braking system.

12. A control method for a vehicle-mounted communication system, the vehicle-mounted communication system having multiple control devices, characterized in that, The plurality of control devices include: a higher-level control device for sending communication frames containing control messages; a mid-level control device for relaying the communication frames sent by the higher-level control device; and a lower-level control device for receiving the communication frames relayed by the mid-level control device and performing control processing based on the control messages contained in the received communication frames. A communication line is connected between the upper-level control device, the middle-level control device, and the lower-level control device so that the communication frame containing the control message sent by the upper-level control device can reach the lower-level control device via at least two communication paths. The control method of the vehicle-mounted communication system includes: As time passes, the host control device repeatedly sends communication frames containing the control message to at least two or more communication paths, and each communication frame contains identification information that can identify the sending order of the communication frames; The lower-level control device, based on the identification information of the received communication frames, determines whether the transmission order of the received communication frames is the same as or older than the transmission order of previously received communication frames; and If the lower-level control device determines that the transmission order of the received communication frames is neither the same as nor older than the transmission order of previously received communication frames, but newer than the transmission order of previously received communication frames, it performs control processing based on the control message contained in the received communication frames. If it determines that the transmission order of the received communication frames is the same as or older than the transmission order of previously received communication frames, it does not perform control processing based on the control message contained in the received communication frames.

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