In-vehicle network system and relay device

Abstract

To allow a group of terminal devices, such as ECUs, that are distributed and connected to a communication bus of a plurality of relay devices to sleep or wake up in conjunction in a large-scale in-vehicle network system.SOLUTION: When a bus management message needs to be sent from one relay device to another, the one relay device refers to a table, creates a PN-compatible bus management message that specifies a cluster requesting the bus management message, and sends it. The other relay device then sends a PN-incompatible bus management message to a communication bus to which terminal devices belonging to the cluster requested by the PN-compatible bus management message are connected.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an in-vehicle network system and a relay device applied to the in-vehicle network system. [Background technology]

[0002] For example, Patent Document 1 discloses a network system that provides partial network functions while suppressing the use of transceivers compatible with partial networks. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-69980 Summary of the Invention [Problem to be solved by the invention]

[0004] A partial network can be defined as a technology that wakes up only ECUs that need to operate, while keeping other ECUs that do not need to operate asleep. As described in Patent Document 1, to realize a partial network, each ECU and gateway (relay device) must use expensive transceivers with complex configurations. Furthermore, communication transceivers compatible with partial networks are limited to CAN (registered trademark, the same applies hereinafter) and CAN-FD (CAN with Flexible Data Rate), etc.

[0005] An example of the use of partial networks is when the sleep or wake-up of each ECU is managed on a communication bus basis, rather than on an ECU basis. This configuration prevents the mixing of sleep and wake-up ECUs on the same bus, eliminating the need to use partial network-compatible (hereinafter sometimes referred to as PN-compatible) communication transceivers for each ECU, and also removing the restrictions on communication protocols that are imposed by limiting communication transceivers to CAN or CAN-FD.

[0006] When managing the sleep or wake-up of each ECU on a communication bus basis, for example, a communication system may be configured to group together a group of ECUs that need to operate simultaneously on a communication bus basis. Furthermore, when a group of ECUs that need to sleep or wake up in tandem spans multiple communication buses via a gateway ECU, the multiple communication buses may be defined as associated communication buses, and a relay device may transfer communication start request information received from a bus management message for causing each ECU to continue waking up between the associated communication buses. In this way, by the relay device transferring the communication start request information between the associated communication buses, a group of ECUs across multiple communication buses may be able to sleep or wake up in tandem.

[0007] However, when the scale of a network system increases, such as in an in-vehicle network system, multiple relay devices may be connected in a multi-stage configuration, and the communication buses of groups of ECUs that need to be put to sleep or wake up in coordination may be connected in a distributed manner under the control of multiple relay devices. In this case, the transmission and reception of bus management messages between the related communication buses in the single relay device described above is not enough to convey which group has generated a communication request, and a problem arises in that it is not possible to put the groups of ECUs that are connected in a distributed manner to the communication buses of the multiple relay devices in a coordinated manner to sleep or wake up.

[0008] The present disclosure has been made in consideration of the above-mentioned points, and aims to provide an in-vehicle network system that enables a group of terminal devices, such as ECUs, that are distributed and connected to the communication buses of multiple relay devices in a large-scale in-vehicle network system to go to sleep or wake up in coordination with one another, and a relay device that is applied to the in-vehicle network system. [Means for solving the problem]

[0009] In order to achieve the above object, a relay device according to the present disclosure includes: A relay device (10, 100) applied to an in-vehicle network system (200) in which sleep or wake-up of terminal devices (26, 28, 32, 34, 126, 128, 132, 134) connected to each communication bus is managed in units of communication buses (24, 30, 124, 130) connected to the relay device (10, 100), The in-vehicle network system includes a plurality of interconnected relay devices, Each of the plurality of relay devices a first conversion unit (S150, S160) that, when receiving a bus management message incompatible with a partial network (PN) for causing a terminal device to continue waking up from a communication bus connecting at least one terminal device and its own relay device, refers to a predefined table and determines that it is necessary to transmit the bus management message to a communication bus connecting another relay device and at least one terminal device, converts the PN-incompatible bus management message into a PN-compatible bus management message that identifies the communication bus to which the bus management message is to be transmitted, and transmits the bus management message to another relay device; The relay device is configured to include a second conversion unit (S300, S320) that, when receiving a PN-compatible bus management message from another relay device, converts the received PN-compatible bus management message into a PN-incompatible bus management message and transmits the converted PN-incompatible bus management message to a communication bus connected to its own relay device identified by the PN-compatible bus management message.

[0010] In addition, the in-vehicle network system (200) according to the present disclosure includes: A first relay device (10); at least first and second communication buses (24, 30) connected to the first relay device; a second relay device (100) connected to the first relay device via a backbone bus (40); at least third and fourth communication buses (124, 130) connected to the second relay device; At least one terminal device (26, 28, 32, 34) is connected to each of the first and second communication buses; At least one terminal device (126, 128, 132, 134) is also connected to the third and fourth communication buses, respectively; An in-vehicle network system in which sleep or wake-up of a terminal device connected to each communication bus is managed in units of a communication bus connected to a first relay device and a second relay device, The first and second relay devices each include: a first conversion unit (S150, S160) that, when receiving a bus management message incompatible with a partial network (PN) for causing a terminal device to continue waking up from any of the communication buses connecting at least one terminal device and its own relay device, refers to a predefined table and determines that it is necessary to transmit the bus management message to any of the communication buses connecting another relay device and at least one terminal device, converts the PN-incompatible bus management message into a PN-compatible bus management message and transmits it to the other relay device; The relay device is configured to include a second conversion unit (S300, S320) that, when receiving a PN-compatible bus management message from another relay device, converts the received PN-compatible bus management message into a PN-incompatible bus management message and transmits the converted PN-incompatible bus management message to a communication bus connected to its own relay device that is requested by the PN-compatible bus management message.

[0011] In the relay device and in-vehicle network system according to the present disclosure, the relay device includes the first conversion unit and the second conversion unit described above. Therefore, even if a group of terminal devices that need to be put to sleep or wake up in a coordinated manner is connected to the communication buses (associated communication buses) of multiple relay devices in a distributed manner, when a bus management message is received on any of the communication buses, the first conversion unit and the second conversion unit can transmit the bus management message to the associated communication bus. Therefore, the relay device and in-vehicle network system according to the present disclosure make it possible to put a group of terminal devices that are connected to the communication buses of multiple relay devices in a distributed manner to sleep or wake up in a coordinated manner.

[0012] The reference numbers in parentheses above merely indicate an example of a correspondence with specific configurations in the embodiments described below, in order to facilitate understanding of the present disclosure, and are not intended to limit the scope of the present disclosure in any way.

[0013] Furthermore, the technical features of the present disclosure other than those described above will become apparent from the following description of the embodiments and the accompanying drawings. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a configuration diagram showing an example of a configuration of an in-vehicle network system according to an embodiment; [Figure 2] FIG. 10 is a diagram illustrating an example of a table. [Figure 3] 10 is a flowchart showing a process executed in the relay device to manage sleep or wake-up of each terminal device. [Figure 4] 10 is a flowchart showing another process executed in the relay device to manage sleep or wake-up of each terminal device. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, a relay device according to the present disclosure and an in-vehicle network system to which the relay device is applied will be described with reference to the drawings.

[0016] FIG. 1 is a configuration diagram showing the configuration of an in-vehicle network system 200 according to this embodiment. As shown in FIG. 1, the in-vehicle network system 200 includes, for example, a central gateway 10 and a subordinate gateway 100 positioned subordinate to the central gateway 10 as relay devices. The central gateway 10 and the subordinate gateway 100 are connected to each other via a backbone bus 40 so that they can communicate with each other. While FIG. 1 shows an example in which the in-vehicle network system 200 includes two gateways, the in-vehicle network system 200 may also be provided with three or more gateways. In this case, the three or more gateways may be connected in a star configuration with the central gateway 10 at the center, or all of the gateways may be connected in series. In this way, any connection topology may be adopted when connecting three or more gateways.

[0017] The in-vehicle network system 200 can use CAN as a communication protocol. However, the communication protocol is not limited to CAN, and the in-vehicle network system 200 can employ various communication protocols such as CAN-FD, Ethernet (registered trademark), FlexRay (registered trademark), and LIN (Local Interconnect Network). Furthermore, in the in-vehicle network system 200, different types of communication protocols may be employed in the different communication buses 24, 30, 40, 124, and 130. In this case, the central gateway 10 and / or the lower gateway 100 are configured to have a conversion function for converting the protocol of a message when transferring a message between communication buses with different communication protocols.

[0018] However, as will be described later, partial network-compatible (PN-compatible) bus management messages must be transmitted and received between the central gateway 10 and the lower gateway 100. For this reason, the backbone bus 40 connecting the central gateway 10 and the lower gateway 100 employs CAN or CAN-FD, which are communication protocols compatible with partial networks.

[0019] A first communication bus 24 and a second communication bus 30 are connected to the central gateway 10. Furthermore, a third communication bus 124 and a fourth communication bus 130 are connected to the lower gateway 100. While Fig. 1 shows an example in which two communication buses 24, 30, 124, and 130 are connected to each of the central gateway 10 and the lower gateway 100, the number of communication buses connected to the central gateway 10 and the lower gateway 100 may be three or more.

[0020] Terminal devices 26 and 28 are connected to the first communication bus 24. Terminal devices 32 and 34 are connected to the second communication bus 30. Terminal devices 126 and 128 are connected to the third communication bus 124. Terminal devices 132 and 134 are connected to the fourth communication bus 130. Each of the terminal devices 26, 28, 32, 34, 126, 128, 132, 134 is an ECU (electronic control unit) for controlling a predetermined control object, a sensor for detecting a predetermined physical quantity, or the like. The number of terminal devices connected to each of the communication buses 24, 30, 124, 130 may be one, or may be three or more.

[0021] In the in-vehicle network system 200 according to this embodiment, terminal devices that do not need to operate are put into a sleep state in order to reduce power consumption. When an operation becomes necessary, the terminal device in the sleep state is woken up and put into a state in which it can control a predetermined control target or detect a predetermined physical quantity.

[0022] Here, the in-vehicle network system 200 according to this embodiment is configured so that the sleep or wake-up of each of the terminal devices 26, 28, 32, 34, 126, 128, 132, and 134 is managed not on a terminal device basis but on a communication bus basis. This eliminates the need to use a transceiver capable of receiving PN-compatible messages in each of the terminal devices 26, 28, 32, 34, 126, 128, 132, and 134, and also removes restrictions on communication protocols.

[0023] To manage the sleep or wake-up of each terminal device 26, 28, 32, 34, 126, 128, 132, and 134 on a communication bus basis, groups of terminal devices 26, 28, 32, 34, 126, 128, 132, and 134 that need to operate at the same time are organized into communication buses. Each terminal device 26, 28, 32, 34, 126, 128, 132, and 134 has a function for determining whether or not it can sleep by sending and receiving a PN-incompatible bus management message. Specifically, each terminal device 26, 28, 32, 34, 126, 128, 132, and 134 periodically sends a PN-incompatible bus management message to the corresponding communication bus 24, 30, 124, and 130 while its own sleep condition is not met. When other terminal devices connected to the same communication bus 24, 30, 124, 130 receive the PN-incompatible bus management message, they continue to wake up even if their own sleep conditions are met. Then, when the sleep conditions of all terminal devices 26, 28, 32, 34, 126, 128, 132, 134 connected to the same communication bus 24, 30, 124, 130 are met, none of the terminal devices 26, 28, 32, 34, 126, 128, 132, 134 transmits the PN-incompatible bus management message. Then, due to a timeout for transmitting and receiving the PN-incompatible bus management message, the group of terminal devices 26, 28, 32, 34, 126, 128, 132, 134 connected to the same communication bus 24, 30, 124, 130 transitions to a sleep state almost simultaneously.

[0024] Here, it is conceivable that a group of terminal devices 26, 28, 32, 34, 126, 128, 132, 134 that need to operate simultaneously may span multiple communication buses (associated communication buses) 24, 30, 124, 130. When these associated communication buses 24, 30, 124, 130 are connected to the same gateway (the central gateway 10 and / or the subordinate gateway 100), the central gateway 10 and / or the subordinate gateway 100 transfers PN-incompatible bus management messages between the associated communication buses, thereby enabling the group of terminal devices 26, 28, 32, 34, 126, 128, 132, 134 that span the multiple communication buses 24, 30, 124, 130 to go to sleep or wake up in unison.

[0025] However, in the case where multiple gateways 10, 100 are connected in multiple stages, as in the in-vehicle network system 200 of this embodiment, and the associated communication buses 24, 30, 124, 130 of a group of terminal devices 26, 28, 32, 34, 126, 128, 132, 134 that need to go to sleep or wake up in coordination are distributed and connected to the multiple gateways 10, 100, the above-mentioned function of transferring PN-incompatible bus management messages between the associated communication buses in the gateways 10, 100 alone is not enough to cause the group of terminal devices 26, 28, 32, 34, 126, 128, 132, 134 that are distributed and connected to the communication buses 24, 30, 124, 130 of the multiple gateways 10, 100 to go to sleep or wake up in coordination.

[0026] Therefore, in the in-vehicle network system 200 according to this embodiment, the central gateway 10 and the subordinate gateway 100 are configured to be able to put into sleep or wake up in cooperation with each other groups of terminal devices 26, 28, 32, 34, 126, 128, 132, 134 that are distributed and connected to the communication buses 24, 30, 124, 130 of the respective gateways 10, 100. The features of this embodiment will be described in detail below.

[0027] The central gateway 10 and the lower gateway 100 are computers that execute various processes for relaying messages between the communication buses 24, 30, 40, 124, and 130. The central gateway 10 and the lower gateway 100 have substantially the same configuration.

[0028] The central gateway 10 and the subordinate gateway 100 each include a processor, memory, and storage. The processor is, for example, a CPU, MPU, GPU, or DFP that executes predetermined processing according to software. The memory is a volatile storage medium, such as RAM, that temporarily stores the results of the processor's arithmetic processing. The storage includes non-volatile storage media such as flash memory and ROM. The storage stores a relay processing program for executing the message relay processing executed by the processor, as well as a table that indicates the communication bus (associated communication bus) to which a bus management message is to be forwarded for each cluster into which terminal devices are grouped. This table will be described in detail later. Note that some or all of the functions of the central gateway 10 and the subordinate gateway 100 may be implemented by hardware using, for example, an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array).

[0029] The central gateway 10 and the subordinate gateway 100 have the function of relaying messages from the communication bus 24, 30, 124, 130 to which the source terminal device 26, 28, 32, 34, 126, 128, 132, 134 is connected to the communication bus 24, 30, 124, 130 to which the destination terminal device 26, 28, 32, 34, 126, 128, 132, 134 is connected, in order to enable sending and receiving of messages between terminal devices 26, 28, 32, 34, 126, 128, 132, 134 connected to different communication buses 24, 30, 124, 130.

[0030] In addition, the central gateway 10 and the subordinate gateway 100 have a function to manage the sleep or wake-up of each of the terminal devices 26, 28, 32, 34, 126, 128, 132, 134 on a per-communication bus 24, 30, 124, 130 basis, including coordinating the sleep or wake-up of groups of terminal devices 26, 28, 32, 34, 126, 128, 132, 134 that are distributed and connected to the communication buses 24, 30, 124, 130 of the respective gateways 10, 100.

[0031] Fig. 2 is a diagram showing an example of the table. As shown in Fig. 2, the table stores clusters into which terminal devices 26, 28, 32, 34, 126, 128, 132, and 134 are grouped, and the clusters are associated with the communication buses 24, 30, 124, and 130 to which the terminal devices 26, 28, 32, 34, 126, 128, 132, and 134 belonging to the clusters are connected. In the example shown in Figs. 1 and 2, the terminal devices 26, 28, 126, and 128 are grouped into cluster 1, and the first communication bus 24, the third communication bus 124, and the backbone bus 40 are stored as the associated communication buses of the terminal devices 26, 28, 126, and 128 belonging to cluster 1. Furthermore, the terminal devices 32, 34, 132, 134 are grouped into cluster 2, and the second communication bus 30, the fourth communication bus 130, and the backbone bus 40 are stored as the associated communication buses of the terminal devices 32, 34, 132, 134 belonging to cluster 2.

[0032] 1 shows, in blocks, the functions realized by software or hardware in the central gateway 10 and the subordinate gateway 100 to manage the sleep or wake-up of each of the terminal devices 26, 28, 32, 34, 126, 128, 132, and 134. As shown in FIG. 1, the central gateway 10 and the subordinate gateway 100 have request conversion units 12 and 112, individual control units 14 and 114, bus management and arbitration units 16 and 116, and bus management units 18, 20, 22, 118, 120, and 122.

[0033] Next, the role of each unit for maintaining a group (cluster) of terminal devices 26, 28, 32, 34, 126, 128, 132, 134 distributed and connected to the communication buses 24, 30, 124, 130 of the central gateway 10 and the subordinate gateway 100 in a wake-up state will be described.

[0034] The bus managers 18, 20, 120, 122 receive PN-incompatible bus management messages from the corresponding communication buses 24, 30, 124, 130. Then, in response to receiving the PN-incompatible bus management messages, the bus managers 18, 20, 120, 122 transmit (return) PN-incompatible bus management messages to the corresponding communication buses 24, 30, 124, 130. In this way, while the PN-incompatible bus management messages are being received from the corresponding communication buses 24, 30, 124, 130, the bus managers 18, 20, 120, 122 also transmit PN-incompatible messages. This ensures that the terminal devices 26, 28, 32, 34, 126, 128, 132, 134 connected to the corresponding communication buses 24, 30, 124, 130 are kept in a wake-up state.

[0035] Unlike the other bus managers 18, 20, 120, and 122, the bus managers 22 and 118 transmit and receive PN-compatible bus management messages between the central gateway 10 and the subordinate gateway 100. For this reason, a partial network-compatible communication protocol is adopted as the communication protocol for the bus management messages transmitted and received between the bus managers 22 and 118. The PN-compatible bus management messages include communication request information indicating the clusters to be maintained in a wake-up state. For example, if there are four clusters (groups) in the network system 200 and communication requests to the four clusters are expressed by 4-bit communication request information, the communication request to the first cluster can be realized by setting the communication request information to "1000."

[0036] The bus management arbitration units 16 and 116 refer to the table and determine the associated communication bus in response to receiving a PN-incompatible bus management message in the bus management units 18, 20, 120, and 122. If an associated communication bus exists, the bus management arbitration units 16 and 116 perform the necessary processing to transmit the bus management message to the associated communication bus.

[0037] For example, when a PN-incompatible bus management message is received from the first communication bus 24, the bus management arbitration unit 16 refers to the table in Fig. 2 and determines that the third communication bus 124 and the backbone bus 40 are related communication buses. If the related communication buses include the backbone bus 40, the bus management arbitration unit 16 notifies the request conversion unit 12 that the PN-incompatible bus management message has been received from the first communication bus 24. On the other hand, if the related communication buses include other communication buses connected to the central gateway 10, the bus management arbitration unit 16 transmits the PN-incompatible bus management message to the other communication buses via the corresponding bus management unit.

[0038] Furthermore, when the bus management units 22 and 118 receive a bus management message corresponding to the PN, the bus management units 22 and 118 notify the bus management arbitration units 16 and 116 that they have received the bus management message corresponding to the PN. In this case, the bus management arbitration units 16 and 116 pass the bus management message corresponding to the PN to the request conversion units 12 and 112.

[0039] When the request conversion unit 12, 112 is notified by the bus management arbitration unit 16, 116 that it has received a PN-incompatible bus management message that needs to be transmitted from a specific communication bus via the backbone bus 40, it references the table in Fig. 2 and generates a bus management message including communication request information that sets a communication request for a cluster associated with the specific communication bus that received the PN-incompatible bus management message, i.e., a PN-compatible bus management message. Furthermore, when the request conversion unit 12, 112 receives a PN-compatible bus management message from the bus management arbitration unit 16, 116, it identifies which cluster the PN-compatible bus management message has a communication request for. The request conversion unit 12, 112 then generates the PN-incompatible bus management message and instructs the bus management arbitration unit 16, 116 to transmit the generated PN-incompatible bus management message to a communication bus connected to a terminal device belonging to the identified cluster. The bus management arbitration unit 16, 116 transmits the PN-incompatible bus management message generated by the request conversion unit 12, 112 to the communication bus to which the terminal device belonging to the identified cluster is connected via the corresponding bus management unit.

[0040] When the request conversion unit 12 generates a PN-compatible bus management message including communication request information that sets a communication request for a specific cluster, the individual control unit 14 transmits the generated PN-compatible bus management message to the backbone bus 40 via the bus management unit 22.

[0041] Next, the role of each unit for transitioning a group (cluster) of terminal devices 26, 28, 32, 34, 126, 128, 132, 134 distributed and connected to the communication buses 24, 30, 124, 130 of the central gateway 10 and the subordinate gateway 100 to a sleep state will be described.

[0042] When the bus management units 18, 20, 120, 122 stop receiving PN-incompatible bus management messages from the corresponding communication buses 24, 30, 124, 130, they also stop transmitting PN-incompatible bus management messages to the corresponding communication buses 24, 30, 124, 130. However, if the corresponding communication buses 24, 30, 124, 130 are requested to communicate by the communication request information in the PN-compatible bus management messages, the bus management units 18, 20, 120, 122 corresponding to the specific communication buses 24, 30, 124, 130 continue transmitting PN-incompatible bus management messages in response to instructions from the bus management arbitration units 16, 116, even if they do not receive PN-incompatible bus management messages from the corresponding communication buses 24, 30, 124, 130. Thus, the terminal devices 26, 28, 32, 34, 126, 128, 132, 134 connected to the corresponding communication buses 24, 30, 124, 130 remain awake.

[0043] For example, suppose that the request conversion unit 112 of the lower gateway 100 generates a PN-compatible bus management message containing a communication request for a specific cluster in response to receiving a PN-incompatible bus management message from a specific communication bus via the bus management arbitration unit 116, and transmits the generated PN-compatible bus management message to the bus management unit 22 of the central gateway 10 via the individual control unit 114, the bus management arbitration unit 116, and the bus management unit 118. If, at a certain timing, the lower gateway 100 stops receiving the PN-incompatible bus management message, the request conversion unit 112 generates a PN-compatible bus management message indicating that there is no communication request for the specific cluster. This PN-compatible bus management message is transmitted to the central gateway 10.

[0044] The request conversion unit 12 of the central gateway 10 determines from the PN-compatible bus management message indicating that there is no communication request to the specific cluster that it is no longer necessary to send bus management messages to the specific cluster. The request conversion unit 12 of the central gateway 10 then instructs the bus management arbitration unit 16 to stop sending PN-incompatible bus management messages to the communication bus to which the terminal device belonging to the specific cluster is connected. This causes the corresponding bus management unit to stop sending bus management messages to the communication bus to which the terminal device belonging to the specific cluster is connected. As a result, if a PN-incompatible bus management message is not being sent from the terminal device connected to the corresponding communication bus, the terminal device connected to the corresponding communication bus transitions to a sleep state.

[0045] Next, the processing executed in the central gateway 10 and the subordinate gateway 100 to manage the sleep or wake-up of each of the terminal devices 26, 28, 32, 34, 126, 128, 132, and 134 will be described with reference to the flowcharts in Figures 3 and 4. The flowcharts in Figures 3 and 4 are executed repeatedly at regular intervals.

[0046] First, we will explain the processing shown in the flowchart of Fig. 3. In the first step S100, the central gateway 10 and the subordinate gateway 100 determine whether or not they have received a PN-incompatible bus management message from any of the communication buses 24, 30, 124, and 130 connected to them. If the central gateway 10 and the subordinate gateway 100 determine that they have received a PN-incompatible bus management message, they proceed to step S110, and if they determine that they have not received a PN-incompatible bus management message, they proceed to step S180.

[0047] In step S110, the central gateway 10 and the lower gateway 100 refer to the table to identify whether there is a communication bus to which the bus management message should be transferred, and if so, which communication bus. That is, in response to receiving a PN-incompatible bus management message, the central gateway 10 and the lower gateway 100 identify the relevant communication bus in step S110.

[0048] In step S120, the central gateway 10 and the lower gateway 100 determine whether or not it is necessary to transfer the bus management message based on the identified associated communication bus. Specifically, if an associated communication bus exists, the central gateway 10 and the lower gateway 100 determine that it is necessary to transfer the bus management message, and proceed to step S130. On the other hand, if an associated communication bus does not exist, the central gateway 10 and the lower gateway 100 determine that it is not necessary to transfer the bus management message, and proceed to step S170.

[0049] In step S130, the central gateway 10 and the lower gateway 100 determine, based on the identified associated communication buses, whether or not the identified associated communication buses include another communication bus connected to themselves, which are the same relay devices. If the central gateway 10 and the lower gateway 100 determine that the identified associated communication buses include another communication bus connected to themselves, they proceed to step S140. On the other hand, if the central gateway 10 and the lower gateway 100 determine that the identified associated communication buses do not include another communication bus connected to themselves, they proceed to step S150.

[0050] In step S140, the central gateway 10 and the lower gateway 100 transmit (transfer) the PN-incompatible bus management message to another communication bus connected to them that is included in the identified associated communication bus.

[0051] In step S150, the central gateway 10 and the lower gateway 100 determine, based on the identified associated communication buses, whether or not the identified associated communication buses include a backbone bus 40 to another relay device and a communication bus connected to another relay device. If the central gateway 10 and the lower gateway 100 determine that the identified associated communication buses include a backbone bus 40 to another relay device and a communication bus connected to another relay device, they proceed to step S160. On the other hand, if the central gateway 10 and the lower gateway 100 determine that the identified associated communication buses do not include a backbone bus 40 to another relay device and a communication bus connected to another relay device, they proceed to step S170.

[0052] In step S160, the central gateway 10 and the lower gateway 100 create a PN-compatible bus management message that sets a communication request to the identified cluster based on the communication bus on which the PN-incompatible bus management message was received, and transmit the message to another relay device via the backbone bus 40.

[0053] In step S170, the central gateway 10 and the lower gateway 100 transmit (return) the PN-incompatible bus management message to the communication buses 24, 30, 124, 130 that received the PN-incompatible bus management message.

[0054] In step S180, which is executed when it is determined that a PN-incompatible bus management message has not been received, the central gateway 10 and the lower gateway 100 determine whether the state in which they received PN-incompatible bus management messages has changed to a state in which reception has stopped. This determination is made for each communication bus connected to them. Then, if the central gateway 10 and the lower gateway 100 have periodically received PN-incompatible bus management messages but have not received a new PN-incompatible bus management message even after a time corresponding to a predetermined transmission / reception timeout has elapsed since the previous reception of the PN-incompatible bus management message, the central gateway 10 and the lower gateway 100 determine that the state in which they received PN-incompatible bus management messages has changed to a state in which reception has stopped. If it is determined that reception has stopped, the central gateway 10 and the lower gateway 100 proceed to step S190. On the other hand, if the time corresponding to the predetermined transmission / reception timeout has not elapsed and it is not determined that reception has stopped, the central gateway 10 and the lower gateway 100 temporarily terminate the processing shown in the flowchart of FIG. 3.

[0055] In step S190, the central gateway 10 and the lower gateway 100 determine whether or not the PN-incompatible bus management message, which has changed from a receiving state to a reception-stopped state, was transferred to another communication bus while being received. If it is determined that it was transferred to another communication bus, the central gateway 10 and the lower gateway 100 proceed to step S200. On the other hand, if it is determined that it was not transferred to another communication bus, the central gateway 10 and the lower gateway 100 proceed to step S240.

[0056] In step S200, the central gateway 10 and the lower gateway 100 determine whether the communication buses they have been forwarding include another communication bus connected to them, which is the same relay device. If the central gateway 10 and the lower gateway 100 determine that the communication buses they have been forwarding include another communication bus connected to them, they proceed to step S210. On the other hand, if the central gateway 10 and the lower gateway 100 determine that the communication buses they have been forwarding do not include another communication bus connected to them, they proceed to step S220.

[0057] In step S210, the central gateway 10 and the lower gateway 100 stop transmitting the PN-incompatible bus management message to another communication bus connected to them, which had been transferring the PN-incompatible bus management message.

[0058] In step S220, the central gateway 10 and the lower gateway 100 determine whether the communication buses used for forwarding included the backbone bus 40 to another relay device and a communication bus connected to another relay device. If the central gateway 10 and the lower gateway 100 determine that the communication buses used for forwarding included the backbone bus 40 to another relay device and a communication bus connected to another relay device, they proceed to step S230. On the other hand, if the central gateway 10 and the lower gateway 100 determine that the communication buses used for forwarding did not include the backbone bus 40 to another relay device and a communication bus connected to another relay device, they proceed to step S240.

[0059] In step S230, the central gateway 10 and the lower gateway 100 create a bus management message corresponding to the PN indicating that there is no communication request to a specific cluster, and transmit the message via the backbone bus 40 to another relay device.

[0060] In step S240, the central gateway 10 and the lower gateway 100 stop sending PN-incompatible bus management messages to the communication buses 24, 30, 124, and 130 that have changed from a state in which they were receiving PN-incompatible bus management messages to a state in which they have stopped receiving them.

[0061] Next, the processing shown in the flowchart of Fig. 4 will be described. In step S300, the central gateway 10 and the subordinate gateway 100 determine whether or not they have received a bus management message corresponding to the PN from the backbone bus 40. If the central gateway 10 and the subordinate gateway 100 determine that they have received a bus management message corresponding to the PN, they proceed to step S310, but if they determine that they have not received a bus management message, they temporarily terminate the processing shown in the flowchart of Fig. 4.

[0062] In step S310, the central gateway 10 and the lower gateway 100 determine whether the received PN-compatible bus management message instructs the transmission of a PN-incompatible bus management message or the suspension of transmission. If it is determined that the message instructs the transmission of a PN-incompatible bus management message, the central gateway 10 and the lower gateway 100 proceed to step S320. On the other hand, if it is determined that the message instructs the suspension of transmission of a PN-incompatible bus management message, the central gateway 10 and the lower gateway 100 proceed to step S330.

[0063] In step S320, the central gateway 10 and the lower gateway 100 create a PN-incompatible bus management message and transmit the created PN-incompatible bus management message to the communication bus to which the terminal device belonging to the cluster requested by the communication request information included in the PN-compatible bus management message is connected.

[0064] In step S330, the central gateway 10 and the lower gateway 100 stop sending PN-incompatible bus management messages to communication buses connected to terminal devices belonging to clusters that do not have communication requests identified by the PN-compatible bus management messages.

[0065] As described above, in the in-vehicle network system 200 according to this embodiment, when a bus management message needs to be transmitted from one relay device to another, the one relay device refers to a table, creates a PN-compliant bus management message that identifies the cluster requesting the bus management message, and transmits the message. That is, the relay device converts the PN-incompatible bus management message into a PN-compliant bus management message. The other relay device then creates a PN-incompatible bus management message from the received PN-compliant bus management message. The other relay device then transmits the created PN-incompatible bus management message to a communication bus connected to a terminal device belonging to the cluster requested by the PN-compliant bus management message.

[0066] Therefore, even if a group of terminal devices that need to be put to sleep or woken up in coordination is distributed and connected to the communication buses of multiple relay devices, it is possible to put the group of terminal devices that are distributed and connected to the communication buses of multiple relay devices to sleep or wake up in coordination.

[0067] The above-described embodiments are preferred embodiments of the present disclosure, but the present disclosure is not limited to the above-described embodiments and can be implemented in various modified forms within the scope that does not deviate from the gist of the present disclosure.

[0068] For example, in the above-described embodiment, when one relay device receives a PN-compliant bus management message indicating that there is no request for a bus management message to a specific cluster from the other relay device, the one relay device is configured to stop transmitting PN-incompatible bus management messages to the communication bus to which the terminal devices belonging to the specific cluster are connected. However, it is not necessary to create and transmit a PN-compliant bus management message indicating that there is no request for a bus management message to the specific cluster from the other relay device. In this case, one relay device may simply stop transmitting PN-incompatible bus management messages to the communication bus to which the terminal devices belonging to the specific cluster are connected in response to not receiving a PN-compliant bus management message requesting a bus management message to the specific cluster for a predetermined period of time. [Explanation of symbols]

[0069] 10: Central gateway, 12: Request conversion unit, 14: Individual control unit, 16: Bus management arbitration unit, 18: Bus management unit, 20: Bus management unit, 22: Bus management unit, 24: First communication bus, 26: Terminal device, 28: Terminal device, 30: Second communication bus, 32: Terminal device, 34: Terminal device, 40: Backbone bus, 100: Lower gateway, 112: Request conversion unit, 114: Individual control unit, 116: Bus management arbitration unit, 118: Bus management unit, 120: Bus management unit, 122: Bus management unit, 124: Third communication bus, 126: Terminal device, 128: Terminal device, 130: Fourth communication bus, 132: Terminal device, 134: Terminal device, 200: In-vehicle network system

Claims

1. A relay device applied to an in-vehicle network system (200) in which sleep or wake-up of terminal devices (26, 28, 32, 34, 126, 128, 132, 134) connected to each communication bus is managed in units of communication buses (24, 30, 124, 130) connected to the relay device (10, 100), the in-vehicle network system is provided with a plurality of interconnected relay devices; Each of the plurality of relay devices a first conversion unit (S150, S160, S220, S230) that, when receiving a bus management message incompatible with a partial network (PN) for causing a terminal device to continue waking up from a communication bus connecting at least one terminal device and its own relay device, refers to a predefined table and determines that it is necessary to transmit a bus management message to a communication bus connecting another relay device and at least one terminal device, converts the PN-incompatible bus management message into a PN-compatible bus management message that identifies a communication bus to which the bus management message is to be sent, and transmits the bus management message to another relay device; a second conversion unit (S300, S320) that, when receiving the PN-compatible bus management message from another relay device, converts the received PN-compatible bus management message into the PN-incompatible bus management message and transmits the converted PN-incompatible bus management message to a communication bus connected to the relay device identified by the PN-compatible bus management message.

2. The relay device described in claim 1, wherein when the PN-incompatible bus management message from the communication bus connecting the at least one terminal device and its own relay device changes from a receiving state to a receiving stop state, the first conversion unit (S220, S230) creates a PN-compatible bus management message instructing the other relay device to stop transmitting the PN-incompatible bus management message to the communication bus identified by the PN-compatible bus management message, and transmits the PN-compatible bus management message to the other relay device.

3. 2. The relay device according to claim 1, further comprising a bus management unit (18, 20, 22, 118, 120, 122, S170, S240) that transmits the PN-incompatible bus management message to the communication bus that received the PN-incompatible bus management message.

4. 4. The relay device according to claim 3, wherein the bus management unit (18, 20, 22, 118, 120, 122, S240) stops transmitting the PN-incompatible bus management message to the communication bus that has stopped receiving the PN-incompatible bus management message.

5. a plurality of communication buses are connected to the relay device; 5. The relay device according to claim 1, further comprising a bus management arbitration unit (16, 116, S130, S140, S200, S210) that, when receiving a PN-incompatible bus management message from a terminal device connected to one of the plurality of communication buses, refers to the table and, if it determines that the PN-incompatible bus management message needs to be transmitted to another of the plurality of communication buses, transmits the PN-incompatible bus management message to the other communication bus.

6. 6. The relay device according to claim 5, wherein the bus management arbitration unit (16, 116, S200, S210) stops transmitting the PN-incompatible bus management message to the other communication bus when reception of the PN-incompatible bus management message from the terminal device connected to one of the plurality of communication buses stops.

7. A first relay device (10); at least first and second communication buses (24, 30) connected to the first relay device; a second relay device (100) connected to the first relay device via a backbone bus (40); at least third and fourth communication buses (124, 130) connected to the second relay device; At least one terminal device (26, 28, 32, 34) is connected to each of the first and second communication buses; At least one terminal device (126, 128, 132, 134) is also connected to the third and fourth communication buses, respectively; an in-vehicle network system in which sleep or wake-up of the terminal devices connected to each communication bus is managed in units of communication buses connected to the first and second relay devices, respectively; The first and second relay devices each include: a first conversion unit (S150, S160) that, when receiving a partial network (PN) incompatible bus management message for causing a terminal device to continue waking up from any communication bus connecting at least one terminal device and its own relay device, refers to a predefined table and determines that it is necessary to transmit a bus management message to any communication bus connecting another relay device and at least one terminal device, converts the PN incompatible bus management message into a PN compatible bus management message that identifies the communication bus to which the bus management message is to be sent, and transmits the PN incompatible bus management message to another relay device; an in-vehicle network system comprising: a second conversion unit (S300, S320) that, when receiving the PN-compatible bus management message from another relay device, converts the received PN-compatible bus management message into the PN-incompatible bus management message and transmits the converted PN-incompatible bus management message to a communication bus connected to its own relay device identified by the PN-compatible bus management message;

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