In-vehicle devices and in-vehicle systems

Abstract

This technology provides a mechanism to prevent communication devices from performing unnecessary communications, even if their power supply is not interrupted. [Solution] When the control unit 53 determines that a communication frame has been transmitted from the ECUs 1 to 3 corresponding to the power supply switching units 31 to 33 that performed switching control to transition to the off state in S313, it proceeds to S314 and determines that the power supply switching units 31 to 33 corresponding to the ECUs 1 to 3 are in a state of interruption failure. In S315, the communication unit 54 transmits a stop frame to the ECUs 1 to 3.

Description

Technical Field

[0001] The present disclosure relates to an in-vehicle device and an in-vehicle system.

Background Art

[0002] Patent Document 1 below describes an in-vehicle system including a power supply device and a plurality of communication devices. The power supply device and each communication device are connected by a power supply line extending from the power supply device and branched according to the number of communication devices. A power supply cutoff unit corresponding to each communication device is provided in the branched power supply line. The power supply cutoff unit cuts off the power supply from the power supply device to the communication device. According to the in-vehicle system of Patent Document 1, since the power supply can be cut off for each communication device, it is also possible to selectively cut off the power supply only for the communication devices in a situation where communication is unnecessary.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, as a result of the inventors' detailed examination, the following problems were found. That is, if the power supply cutoff unit fails, there is a possibility that the power supply cannot be cut off. Even a communication device that should originally be in a situation where communication is unnecessary will perform unnecessary communication if the power supply is not cut off.

[0005] One aspect of the present disclosure provides a technique in which a communication device does not perform unnecessary communication even when the power supply to the communication device is not cut off.

Means for Solving the Problems

[0006] One aspect of this disclosure is an in-vehicle device (5, 5a, 5b) used in an in-vehicle system (100, 200, 300, 400) equipped with a plurality of communication devices (1-3, 1a-1f). Each of the plurality of communication devices is configured to receive power through its respective power supply path (21-23). ​​Each power supply path is provided with a power supply switching unit (31-33, 61-69) configured to switch between an ON state, which allows conductivity through the power supply path, and an OFF state, which blocks the power supply path. The in-vehicle device comprises a control unit (53) and a communication unit (54). The control unit is configured to perform switching control to control whether to switch the power supply switching unit to the ON state or the OFF state. The communication unit is configured to communicate with the plurality of communication devices. When the control unit receives a communication frame from a communication device corresponding to a power supply switching unit for which it has performed switching control to transition to the off state, it determines that the power supply switching unit is in a state of interruption failure, meaning it is unable to transition to the off state. If the control unit performs switching control to transition one of the power supply switching units to the off state, and the control unit determines that the said power supply switching unit is in a state of interruption failure, the communication unit sends a stop frame, which is a communication frame instructing the communication device corresponding to the said power supply switching unit to stop the transmission process of sending a communication frame.

[0007] With this configuration, even if the power supply path is not actually interrupted, the multiple communication devices can recognize that they should stop transmitting. Therefore, the multiple communication devices can simulate the situation when the power supply switching unit is actually switched off and stop transmitting. Consequently, even if the power supply to the multiple communication devices is not interrupted, the multiple communication devices will not perform unnecessary communications.

[0008] One aspect of this disclosure may be an in-vehicle system (100, 200, 300, 400) on which a plurality of communication devices (1-3, 1a-1f) and in-vehicle devices (5, 5a, 5b) are mounted. [Brief explanation of the drawing]

[0009] [Figure 1] This is a block diagram showing the configuration of the communication system of the embodiment. [Figure 2] This is a block diagram of the electronic control unit. [Figure 3] Figure 3A is a diagram illustrating an example of management information, and Figure 3B is a diagram illustrating an example of switching control. [Figure 4] Figure 4A is an example of a list showing the correspondence between the power supply switching unit and the connected ECU, and Figure 4B is an example of a stop frame and a start frame. [Figure 5] This is a sequence diagram showing the switching process from the ON state to the OFF state when the device is stuck in the ON state. [Figure 6] This is a sequence diagram showing the switching process to the ON state when the device is stuck in the ON position. [Figure 7] This flowchart shows the process when switching control is performed. [Figure 8] This is a flowchart showing the process when stopping or starting the transmission process. [Figure 9] This is a block diagram showing the configuration of the communication system in the modified example 1. [Figure 10] This is a block diagram showing the configuration of the communication system in variation 2. [Figure 11] This is a block diagram showing the configuration of the communication system in the modified example 3. [Modes for carrying out the invention]

[0010] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings. [1. Embodiments] [1-1. Structure] The communication system 100 shown in Figure 1 constitutes a network system installed in a vehicle, such as a passenger car. The communication system 100 is an in-vehicle system equipped with multiple electronic control units (hereinafter referred to as ECUs 1 to 5). The multiple ECUs 1 to 5 are connected to each other via communication lines, enabling data communication. ECU stands for "Electronic Control Unit".

[0011] ECUs 1-5 receive power from a battery 6 mounted in the vehicle via power lines. Battery 6 supplies power at a DC battery voltage (e.g., 12V). Power lines branch off from battery 6 and extend to form power supply paths 21-23. In this embodiment, ECU1 receives power from battery 6 via power supply path 21 between battery 6 and ECU1. ECU2 receives power from battery 6 via power supply path 22 between battery 6 and ECU2. ECU3 receives power from battery 6 via power supply path 23 between battery 6 and ECU3. Power supply paths for ECUs 4 and 5 are not shown in the illustration, but ECUs 4 and 5 also receive power from battery 6.

[0012] ECUs 1-5 are configured to transition between a wake-up state, which is the normal operating state, and a sleep state, which is a low-power operating state in which at least some of their functions are restricted. For example, in the wake-up state, ECUs 1-5 can use all of their functions. On the other hand, in the sleep state, ECUs 1-5 may have functions other than the reception processing described later restricted. ECUs 1-5 transition from the wake-up state to the sleep state if they do not receive a communication request from any of the ECUs. In other words, ECUs 1-5 transition to the sleep state if they do not receive a communication request from any of the ECUs for a predetermined time set in advance. On the other hand, ECUs 1-5 maintain the wake-up state if they receive a communication request from any of the ECUs.

[0013] For example, if power is no longer supplied from battery 6 to each ECU1-5, each ECU1-5 will stop sending communication requests and enter a sleep state. In other words, if all ECU1-5 that make up the communication system 100 stop sending communication requests, all ECU1-5 will stop receiving communication requests, and the entire communication system 100 will enter a low-power state. A communication request represents a request to send a communication frame.

[0014] Power supply paths 21 to 23 are each provided with power supply switching units 31 to 33. The power supply switching units 31 to 33 are configured to switch between an on state in which each power supply path is made conductive and an off state in which each power supply path is cut off. The power supply switching units 31 to 33 are constituted by, for example, a mechanical relay having mechanical contacts or a semiconductor relay not having mechanical contacts. In the present embodiment, the power supply switching units 31 to 33 are constituted by semiconductor relays such as FETs. The control unit 53 described later applies a gate voltage to the gate terminal of the FET, whereby the FET is switched to the on state. Note that the power supply switching units 31 to 33 may be illustrated as SW31 to 33.

[0015] As shown in FIG. 2, the ECU 1 includes a CPU 11 and a memory 12. A program for the CPU 11 to execute a predetermined function is stored in the memory 12. The ECU 1 realizes functions as the following respective units when the CPU 11 executes the program in the memory 12. That is, the ECU 1 has functions as a communication unit 13 and an abnormality detection unit 14.

[0016] The communication unit 13 is configured to be able to communicate with the ECUs 2 to 5. More specifically, the communication unit 13 executes transmission processing for transmitting a communication frame and reception processing for receiving a communication frame. The communication unit 13 is configured to be able to receive a stop frame and a start frame described later. The communication unit 13 is configured to be able to receive not only the stop frame and the start frame for itself but also the stop frame and the start frame for other ECUs.

[0017] The abnormality detection unit 14 is configured to execute communication abnormality detection (hereinafter also referred to as abnormality detection processing) for detecting whether there is an abnormality in the communication state of the communication system 100. For example, as communication abnormality detection, the abnormality detection unit 14 executes a break determination for determining whether a communication frame that should be received from another ECU has been interrupted. More specifically, when the state of not receiving a communication frame transmitted from another ECU continues for a preset communication abnormality determination time (for example, 2 seconds), the abnormality detection unit 14 determines that a communication abnormality has occurred between the other ECU and the communication state of the communication system is abnormal.

[0018] When ECU1 receives a stop frame, it stops the transmission process by the communication unit 13 and also stops the communication abnormality detection by the abnormality detection unit 14. On the other hand, when ECU1 receives a start frame, it starts the transmission process by the communication unit 13 and also starts the communication abnormality detection by the abnormality detection unit 14.

[0019] Although the block diagrams of ECU2 and 3 are not shown, ECU2 and 3 have the same configuration as ECU1. Returning to FIG. 1, ECU4 includes a CPU41 and a memory 42. A program for the CPU41 to execute a predetermined function is stored in the memory 42.

[0020] ECU4 realizes functions as the following respective units when the CPU41 executes the program in the memory 42. That is, ECU4 has functions as a power state management unit 43 and a communication unit 44.

[0021] The power state management unit 43 is configured to manage whether each power supply switching unit 31 to 33 should transition to the ON state or the OFF state according to the vehicle's driving state. As an example, as shown in Figure 3A, the power state management unit 43 preclassifies the power state and manages it as management information. Management information is information indicating whether the power supply switching units 31 to 33 should transition to the ON state or the OFF state. For example, a rule is predefined that state A indicates a state in which power is supplied to ECU1 and ECU2, but not to ECU3. In other words, state A indicates that power supply switching units 31 and 32 should transition to the ON state, but power supply switching unit 33 should transition to the OFF state.

[0022] For example, a rule is pre-defined that state B indicates a state where power is supplied to ECU2, but not to ECU1 and ECU3. In other words, state B indicates that the power supply switching unit 32 should transition to the ON state, but the power supply switching units 31 and 33 should transition to the OFF state. For example, a rule is pre-defined that state C indicates that power is supplied to ECU1-3. In other words, state C indicates that the power supply switching units 31-33 should transition to the ON state.

[0023] For example, the power state management unit 43 manages the relationship between the vehicle's driving state and a state, such as determining that when the driving state changes from one where cruise control is active to one where cruise control is deactivated, it should change from state B to state C.

[0024] The communication unit 44 is configured to communicate with ECUs 1-3 and 5. The power status management unit 43 notifies the control unit 53 of ECU 5, which will be described later, of the management information via the communication unit 44. The ECU 5 comprises a CPU 51 and a memory 52. ​​The memory 52 stores a program that allows the CPU 51 to perform a predetermined function.

[0025] The ECU 5 performs the following functions by having the CPU 51 execute the program stored in the memory 52. ​​Specifically, the ECU 5 includes the functions of a control unit 53, a communication unit 54, and a storage unit 55.

[0026] The control unit 53 is configured to perform switching control to control whether to switch the power supply switching units 31-33 to the ON state or the OFF state. The control unit 53 performs switching control according to the management information notified by the power supply state management unit 43. As shown in Figure 3B, the case in which state A is notified as management information will be explained as an example. In the case of state A, a rule is set in advance to switch the power supply switching unit 31 and power supply switching unit 32 to the ON state and switch the power supply switching unit 33 to the OFF state. The control unit 53 applies gate voltage to the gate terminals of the power supply switching unit 31 and power supply switching unit 32. On the other hand, the control unit 53 stops applying gate voltage to the gate terminal of the power supply switching unit 33.

[0027] Similarly, when state B is notified, the rule is set to switch the power supply switching unit 32 to the ON state and switch the power supply switching units 31 and 33 to the OFF state. When state C is notified, the rule is set to switch the power supply switching units 31, 32, and 33 to the ON state. The control unit 53 performs switching control according to the type of state notified by the power supply state management unit 43.

[0028] In this case, even if the control unit 53 stops applying the gate voltage to the gate terminal, an abnormality may occur in which the power supply switching unit does not switch to the off state but remains in the on state (hereinafter also referred to as "on-fixed").

[0029] The control unit 53 is also configured to determine whether the power supply switching units 31-33 are in a state of interruption failure, meaning they are unable to transition to the off state. More specifically, the control unit 53 is configured to determine whether the power supply switching units 31-33 are stuck on. Specifically, for each of the power supply switching units 31-33, if the control unit 53 receives a communication frame from the ECUs 1-3 corresponding to the power supply switching unit 31-33 that performed the switching control to transition to the off state, it determines that the power supply switching units 31-33 are in a state of interruption failure. In other words, if the control unit 53 receives any communication frame from the ECUs 1-3 corresponding to the power supply switching unit 31-33 that performed the switching control, even after performing the switching control to transition to the off state, it determines that the power supply switching units 31-33 are stuck on.

[0030] Normally, when the power supply switching units 31-33 transition to the off state, power to the ECUs 1-3 corresponding to the power supply switching units 31-33 is cut off, and the transmission process should also stop. Therefore, communication frames should not be transmitted from ECUs 1-3. Nevertheless, the fact that communication frames were received from ECUs 1-3 suggests that the power supply switching units 31-33 are stuck in the on state, and power to ECUs 1-3 cannot be cut off.

[0031] The control unit 53 also holds information linking the power supply switching unit and the ECU corresponding to the power supply switching unit (hereinafter also referred to as the connected ECU). For example, as shown in Figure 4A, the control unit 53 holds a list that associates the power supply switching unit with the connected ECU.

[0032] Furthermore, the control unit 53 instructs the communication unit 54 to transmit a stop frame and a start frame. More specifically, the control unit 53 performs switching control to transition one of the power supply switching units 31 to 33 to the off state, and if it determines that the said power supply switching unit is in a state of interruption failure, it instructs the communication unit 54 to transmit a stop frame. A stop frame is a communication frame that instructs the ECU corresponding to the said power supply switching unit to stop the transmission process that transmits a communication frame.

[0033] Furthermore, the control unit 53 performs switching control to transition one of the power supply switching units 31 to 33 to the ON state, and if it determines that the said power supply switching unit is in a state of interruption failure, it instructs the communication unit 54 to transmit a start frame. The start frame is a communication frame that instructs the ECU corresponding to the said power supply switching unit to start the transmission process of transmitting a communication frame.

[0034] As an example, as shown in Figure 4B, communication frames representing transmission processing instruction signals are used as stop frames and start frames. A transmission processing instruction signal is a signal that represents an instruction to stop transmission or an instruction to allow transmission; "1" represents an instruction to stop transmission, and "0" represents an instruction to allow transmission. For example, the first upper bit of the data field is linked to ECU1, the second upper bit is linked to ECU2, and the third upper bit is linked to ECU3.

[0035] For example, different communication frames may be used for the stop frame and start frame for each ECU. Also, for example, the stop frame and the start frame may be transmitted as separate communication frames.

[0036] The communication unit 54 is configured to communicate with ECUs 1 to 4. The communication unit 54 transmits a stop frame and a start frame according to the instructions of the control unit 53. In other words, if the control unit 53 performs switching control to transition power supply switching unit 1 to the off state, and the control unit 53 determines that power supply switching unit 1 is in a state of interruption failure, the communication unit 54 transmits a stop frame. On the other hand, if the control unit 53 performs switching control to transition power supply switching unit 1 to the on state, and the control unit 53 determines that power supply switching unit 1 is in a state of interruption failure, the communication unit 54 transmits a start frame.

[0037] The memory unit 55 stores at least the location of the fault. More specifically, the memory unit 55 stores the power supply switching unit that the control unit 53 has determined to be in a state of interruption failure, and the ECU connected to the power supply switching unit.

[0038] [1-2. Processing] [1-2-1. Switching process to the OFF state when the ON state is stuck] The process performed in the communication system 100 (hereinafter referred to as the switching process) will be explained below. First, the outline of the switching process to the off state when the system is stuck on will be explained using the sequence diagram in Figure 5. This sequence diagram is explained on the premise that the power supply switching unit 33 is stuck on. This switching process is repeatedly executed at a predetermined interval while the power supply state management unit 43 is operating. This switching process may also be executed whenever the vehicle's driving state changes and a situation arises where the power supply state needs to be changed.

[0039] First, in S101, the power state management unit 43 determines the power state. More specifically, the power state management unit 43 decides which state to transition to depending on the vehicle's driving state. For example, the power state management unit 43 decides that it should transition to state A.

[0040] Next, in S102, the power state management unit 43 notifies the control unit 53 of the management information. For example, the power state management unit 43 notifies the control unit 53 of state A, which was determined in S201. Next, in S103, the control unit 53 acquires management information. Furthermore, since the control unit 53 retains management information previously notified by the power status management unit 43, it updates the retained management information when new management information is notified.

[0041] Next, in S104, the control unit 53 refers to the fault memory. More specifically, the control unit 53 checks whether the fault location is stored in the memory unit 55. Next, in S105, the control unit 53 performs switching control according to the management information. More specifically, it performs switching control of each power supply switching unit 31 to 33 according to the value of the state. For example, the control unit 53 performs switching control of each power supply switching unit 31 to 33 according to the value of state A.

[0042] As shown in S106, the control unit 53 switches the power supply switching unit 33 to the off state. However, as shown in S107, the power supply switching unit 33 is stuck in the ON position. Therefore, the power supply path 23 is not interrupted, and as shown in S115, the ECU 3 remains powered. Normally, the transmission process should stop when the power supply to the ECU 3 is stopped, but because the ECU 3 is still powered, as shown in S109, the ECU 3 continues the transmission process.

[0043] In S108, the control unit 53 identifies the ECU connected to the faulty power supply switching unit (i.e., the faulty part). More specifically, the control unit 53 checks the connected ECU associated with the faulty part, which is stored in the memory unit 55.

[0044] As in S110, when the communication unit 54 receives a communication frame from the ECU 3, in S111 the control unit 53 determines that the power supply switching unit 33 is in a state of interruption failure. For example, if the ECU 3 is not stored in the storage unit 55 as the connected ECU associated with the fault location, the control unit 53 detects that the power supply switching unit 33 has newly failed (i.e., the power supply switching unit 33 has become stuck in the ON position).

[0045] In S112, the communication unit 54 transmits a stop frame. Specifically, the communication unit 54 notifies the ECU 3 to stop the transmission process. ECU3 stops the transmission process, as shown in S113, because it has received a stop frame directed to it. In other words, ECU3 stops the transmission process even if it is still powered on. As a result, the transmission process, which would normally have stopped when power to ECU3 was cut off, is stopped. Note that ECU3 does not stop the reception process. This is because, as will be explained in detail later, it may receive a start frame and resume the transmission process.

[0046] In S114, the control unit 53 stores the newly failed power supply switching unit and connected ECU. Specifically, if the power supply switching unit 33 and ECU 3 are not stored in the storage unit 55 as the faulty part and the connected ECU associated with the faulty part, the control unit 53 newly stores the power supply switching unit 33 and ECU 3 in the storage unit 55.

[0047] [1-2-2. Switching process to the ON state when the ON state is stuck] The sequence diagram in Figure 6 will be used to explain the general process of switching to the ON state when the ON state is stuck. This sequence diagram assumes that the power supply switching unit 33 is stuck in the ON state. It also assumes the state after steps S112 and S113 of the sequence diagram in Figure 5 have been executed. In other words, it assumes that the power supply switching unit 33 is stuck in the ON state, the power supply path 23 is not interrupted, the ECU 3 is energized, but the transmission process has been stopped.

[0048] First, when the vehicle's driving state changes and a situation arises where the power supply state should be changed, in S201, the power supply state management unit 43 determines the new power supply state. For example, the power supply state management unit 43 decides that the system should transition to state C.

[0049] Next, in S202, the power state management unit 43 notifies the control unit 53 of the management information. For example, the power state management unit 43 notifies the control unit 53 of state C determined in S201. Next, in S203, the control unit 53 acquires management information. The control unit 53 also updates the currently held management information with the new management information.

[0050] Next, in S204, the control unit 53 refers to the fault memory. As a prerequisite, the memory unit 55 stores the fault location and the connected ECU associated with the fault location, namely the power supply switching unit 33 and the ECU 3.

[0051] Next, in S205, the control unit 53 performs switching control according to the management information. Specifically, the control unit 53 performs switching control of each power supply switching unit 31 to 33 according to the value of state C.

[0052] As shown in S206, the control unit 53 switches the power supply switching unit 33 to the ON state. Here, as in S207, the power supply switching unit 33 remains stuck in the ON position. Therefore, the power supply path 23 is not interrupted, and as in S212, the ECU 3 remains energized. Normally, as the power supply to the ECU 3 transitions from stopped to started, the transmission process should also change from stopped to started, but as described in the premise, the ECU 3 is energized and the transmission process is stopped (S210).

[0053] When the control unit 53 switches the power supply switching unit corresponding to the ECU stored in the memory unit 55 to the ON state, in S208 it instructs the communication unit 54 to send a start frame to the ECU stored in the memory unit 55. Specifically, since the power supply switching unit 33 and ECU 3 are stored in the memory unit 55, the control unit 53 instructs the communication unit 54 to send a start frame to ECU 3.

[0054] In S209, the communication unit 54 transmits a start frame. Specifically, the communication unit 54 notifies the ECU 3 to start the transmission process. ECU3, having received the start frame for itself, begins the transmission process as shown in S211. This initiates the transmission process that would normally start when power is supplied to ECU3.

[0055] [1-2-3. Processing when executing switching control] The flowchart in Figure 7 illustrates the process when the ECU 5 performs switching control. This process is executed each time management information is notified from the power state management unit 43.

[0056] First, in S301, the control unit 53 acquires the power status. Specifically, the control unit 53 acquires management information from the power status management unit 43 via the communication unit 54. Next, in S302, the control unit 53 refers to the fault memory.

[0057] Next, in S303, the control unit 53 determines whether or not the fault location is stored in memory. If the control unit 53 determines in S303 that nothing has been stored regarding the fault location, it proceeds to S304. In other words, if no ON lock occurred in any of the power supply switching units 31-33 when this process was last executed, the control unit 53 proceeds to S304.

[0058] In S304, the control unit 53 performs switching control of the power supply switching units 31 to 33. In S305, the control unit 53 determines whether or not a communication frame has been transmitted from the ECUs 1 to 3 (hereinafter also referred to as the ECUs to be shut off) corresponding to the power supply switching units 31 to 33 that have performed switching control to transition to the off state.

[0059] If the control unit 53 determines in S305 that no communication frames were transmitted from the ECU to be shut down, it terminates this switching process. Not receiving a communication frame from the ECU to be shut down suggests that the transmission process of the ECU to be shut down has stopped. In other words, it is considered that the power supply switching unit corresponding to the ECU to be shut down has not become stuck in the ON state and has switched to the OFF state normally.

[0060] On the other hand, if the control unit 53 determines in S305 that a communication frame has been transmitted from the ECU to be shut off, it proceeds to S306 and determines that the power supply switching unit corresponding to the ECU to be shut off is in a state of shutdown failure. Receiving a communication frame from the ECU to be shut off indicates that the power supply switching unit corresponding to the ECU to be shut off is stuck on, and that power to the ECU to be shut off cannot be cut off.

[0061] Next, in S307, the communication unit 54 transmits a stop frame to the ECU to be blocked. Next, in S308, the control unit 53 stores in the storage unit 55 the power supply switching unit and the ECU to be shut off that it has determined to be in a state of interruption failure.

[0062] On the other hand, if the control unit 53 determines in S303 that the fault location has been stored, it proceeds to S309. In other words, if an ON lock occurred in any of the power supply switching units 31-33 when this process was last executed, the control unit 53 proceeds to S309.

[0063] In S309, the control unit 53 performs switching control of the power supply switching units 31 to 33. Next, in S310, the control unit 53 determines whether the switching control for the power supply switching unit, which was stored as a faulty part, was a switch to the off state.

[0064] If the control unit 53 determines in S310 that the switching control for the power supply switching unit, which was stored as a faulty part, was not a switch to the off state (i.e., a switch to the on state), it proceeds to S311.

[0065] In S311, the communication unit 54 transmits a start frame to the ECU corresponding to the power supply switching unit that was stored as the faulty location. In other words, the communication unit 54 notifies the ECU connected to the power supply switching unit where the ON-fixed fault is occurring to resume the transmission process.

[0066] On the other hand, if the control unit 53 determines that the switching control for the power supply switching unit, which was stored as a faulty part in S310, was a switch to the off state, it proceeds to S312. In S312, the communication unit 54 transmits a stop frame to the ECU corresponding to the power supply switching unit that was stored as the faulty location. In other words, the communication unit 54 notifies the ECU connected to the power supply switching unit where the ON-fixed fault is occurring to stop the transmission process.

[0067] Next, in S313, the control unit 53 determines whether or not a communication frame has been transmitted from the ECU to be shut down. In other words, the control unit 53 determines whether it has received any communication frames from the ECUs 1 to 3 corresponding to the power supply switching units 31 to 33, which were switched to the OFF state in S309. More specifically, the control unit 53 determines whether it has received a communication frame from the ECU corresponding to the power supply switching unit that is not stored as a fault location among the ECUs to be shut down. In other words, if there is a newly failed power supply switching unit that is not yet stored as a fault location in the storage unit 55, the control unit 53 determines whether it has received a communication frame from the ECU corresponding to the newly failed power supply switching unit.

[0068] If the control unit 53 determines in S313 that no communication frames were transmitted from the ECU to be shut down, it terminates this switching process. Not receiving communication frames from the ECU to be shut down is normal, and it is considered that there were no newly malfunctioning power supply switching units.

[0069] On the other hand, if the control unit 53 determines in S313 that a communication frame has been transmitted from the ECU to be shut off, it proceeds to S314 and determines that the power supply switching unit corresponding to the ECU to be shut off is in a state of shutdown failure. Normally, the ECU to be shut off should not receive a communication frame, so it is thought that there is a newly malfunctioning power supply switching unit.

[0070] Next, in S315, the communication unit 54 transmits a stop frame to the ECU connected to the power supply switching unit, which is now suspected to have malfunctioned. Next, in S316, the control unit 53 stores in the storage unit 55 the power supply switching unit that is newly considered to have failed, and the ECU connected to the power supply switching unit. After that, the ECU 5 terminates this switching process.

[0071] [1-2-4. Processing when stopping or starting the transmission process] The flowchart in Figure 8 illustrates the process that occurs when ECUs 1-3 receive a stop frame or start frame and stop or start the transmission process. This process is repeatedly executed, for example, while the ignition switch is ON.

[0072] First, in S401, ECUs 1-3 determine whether or not they have received a transmission processing instruction signal from ECU 5. More specifically, ECUs 1-3 determine whether or not they have received a stop frame or a start frame. For example, if ECUs 1-3 receive a communication frame with a pre-set communication ID, they determine that they have received a transmission processing instruction signal.

[0073] If ECU1-3 determines in S401 that it did not receive the transmission processing instruction signal, it returns to the beginning of this switching process. On the other hand, if ECU1-3 determines that it has received the transmission processing instruction signal, it proceeds to S402.

[0074] In S402, ECUs 1-3 determine the transmission permission status for the other ECUs. More specifically, ECUs 1-3 check whether the bit in the data field corresponding to each ECU is "1" (i.e., instruction to stop transmission) or "0" (i.e., instruction to allow transmission).

[0075] Next, ECUs 1-3 perform anomaly detection processing corresponding to the transmission permission status of other ECUs. More specifically, if ECUs 1-3 receive any communication frame from an ECU that has been instructed to stop transmitting, they do not use that communication frame for anomaly detection processing. In principle, an ECU that has been instructed to stop transmitting should not perform any transmission processing. Therefore, even if they receive a communication frame from an ECU that should not be performing any transmission processing, ECUs 1-3 ignore that communication frame because its reliability is low. On the other hand, if ECUs 1-3 receive any communication frame from an ECU that has been instructed to allow transmitting, they use that communication frame for anomaly detection processing.

[0076] Next, in S404, ECU1-3 determine whether or not they have been instructed to stop transmitting. More specifically, ECU1-3 check whether the bit in the data field corresponding to their own ECU is "1" (i.e., instruction to stop transmitting) or "0" (i.e., instruction to allow transmitting).

[0077] If ECU1-3 determines in S404 that it has not received a command to stop transmission (i.e., it determines that it has received a command to allow transmission), it proceeds to S405.

[0078] In S405, ECU1-3 determine whether the transmission process is continuing or not. If ECU1-3 determines in S405 that the transmission process is not ongoing (i.e., that the transmission process is stopped), it proceeds to S406 and starts the transmission process.

[0079] On the other hand, if ECU1-3 determines in S405 that the transmission process is still ongoing, it terminates this process. On the other hand, if ECU1-3 determines in S404 that it has been instructed to stop transmitting, it proceeds to S407.

[0080] In S407, ECU1-3 determine whether the transmission process is ongoing or not. If ECU1-3 determines in S407 that the transmission process is not ongoing, it proceeds to S408 and stops the communication anomaly detection. Communication anomaly detection is a process that should not be executed when the power supply is cut off (in other words, when in sleep mode). Furthermore, executing communication anomaly detection at a time when it should not be executed may lead to a false positive. Therefore, from the perspective of not executing unnecessary processes, communication anomaly detection is stopped when the power supply switching unit is stuck in the ON position.

[0081] On the other hand, if ECU1-3 determines in S407 that the transmission process is still ongoing, it proceeds to S409. At S409, ECUs 1-3 stop the transmission process.

[0082] Next, at S410, ECUs 1-3 also stop detecting communication anomalies. After that, ECUs 1-3 terminate this process. [1-3. Effects] According to the embodiments described in detail above, the following effects can be obtained.

[0083] (1a) When the control unit 53 receives a communication frame from the ECUs 1 to 3 corresponding to the power supply switching units 31 to 33 that have performed switching control to transition to the off state, it determines that the power supply switching units 31 to 33 are in a state of interruption failure. When the control unit 53 has performed switching control to transition one power supply switching unit to the off state, and the control unit 53 has determined that the one power supply switching unit is in a state of interruption failure, the communication unit 54 transmits a stop frame to the ECU corresponding to the one power supply switching unit. With this configuration, even if the power supply path is not actually interrupted, the ECUs 1 to 3 can recognize that they should stop the transmission process. Therefore, the ECUs 1 to 3 can stop the transmission process as if the power supply switching units 31 to 33 had actually switched to the off state. Consequently, even if the power supply to the ECUs 1 to 3 is not interrupted, the ECUs 1 to 3 will not perform unnecessary communications.

[0084] (1b) When the control unit 53 performs switching control to transition the power supply switching unit 1 to the ON state, and the control unit 53 determines that the power supply switching unit 1 is in a state of interruption failure, the communication unit 54 transmits a start frame to the ECU corresponding to the power supply switching unit 1. With this configuration, even if the transmission process is stopped when the power supply switching units 31 to 33 are stuck in the ON state, the transmission process can be restarted. Therefore, at the timing when the transmission process should have been executed, the ECUs 1 to 3 can start the transmission process appropriately.

[0085] (1c) When ECU1~3 receives a stop frame, it stops the transmission process and also stops the communication anomaly detection by the anomaly detection unit 14. With this configuration, just like the transmission process, it is possible to stop the communication anomaly detection, which would not normally be performed when the power supply paths 21~23 are interrupted. Therefore, just like the transmission process, ECU1~3 will not perform unnecessary processing. Furthermore, if communication anomaly detection is performed at a time when it should not be performed, it may lead to a false positive. However, since ECU1~3 does not perform unnecessary communication anomaly detection, false positives can be suppressed.

[0086] Furthermore, when ECUs 1-3 receive a start frame, they begin the transmission process and simultaneously initiate communication anomaly detection by the anomaly detection unit 14. With this configuration, even if communication anomaly detection is stopped due to an ON lock-up in the power supply switching units 31-33, communication anomaly detection can be restarted. Therefore, ECUs 1-3 can appropriately initiate communication anomaly detection at the timing when it should have been performed.

[0087] (1d) ECUs 1-5 have a wake-up state and a sleep state. ECUs 1-5 are configured to transition to the sleep state if they do not receive a communication request from any of the other ECUs. If the power supply switching units 31-33 are stuck on, and ECUs 1-3 cannot stop the transmission process, they will send a communication request, preventing the other ECUs constituting the communication system 100 from transitioning to the sleep state. Therefore, the power consumption of the communication system 100 is not reduced. Battery drain may also occur. However, with the above configuration, even if the power supply switching units 31-33 are stuck on, ECUs 1-3 can stop the transmission process. Therefore, ECUs 1-3 will also stop sending communication requests. If all ECUs 1-5 constituting the communication system 100 can stop the transmission process, all ECUs 1-5 will stop sending communication requests, and ECUs 1-5 can transition to the sleep state. Therefore, the power consumption of the communication system 100 can be reduced.

[0088] (1e) ECUs 1-3 can receive stop and start frames for themselves, as well as stop and start frames for other ECUs. When ECUs 1-3 receive a communication frame from an ECU that has been instructed to stop the transmission process, they do not use the information in that communication frame for communication anomaly detection by the anomaly detection unit 14. On the other hand, when ECUs 1-3 receive a communication frame from an ECU that has been instructed to start the transmission process, they use the information in that communication frame for communication anomaly detection by the anomaly detection unit 14. Here, an ECU that has been instructed to stop the transmission process should not be performing the transmission process. Therefore, communication frames received from an ECU that should not be performing the transmission process may have low data reliability. With the above configuration, ECUs 1-3 do not use communication frames received from an ECU that should not be performing the transmission process for communication anomaly detection, thus avoiding the use of communication frames with low data reliability. Furthermore, using communication frames with low data reliability may lead to misjudgments, but with the above configuration, ECUs 1-3 do not use such communication frames, thus suppressing misjudgments.

[0089] On the other hand, ECUs 1-3 can properly perform communication anomaly detection when they receive a communication frame from an ECU that has been instructed to start the transmission process, as they use this frame for communication anomaly detection. [1-4. Correspondence] In the above embodiment, ECUs 1 to 3 correspond to multiple communication devices, and ECU 5 corresponds to an in-vehicle device.

[0090] [2. Other Embodiments] While embodiments of this disclosure have been described above, it goes without saying that this disclosure is not limited to the embodiments described above and can take various forms.

[0091] (2a) In the above embodiment, a configuration in which the power supply switching units 31 to 33 are provided outside the ECU 5 was illustrated. However, as shown in the communication system 200 of the modified example 1 in Figure 9, for example, the power supply switching units 31 to 33 may be provided inside the ECU 5.

[0092] (2b) In the above embodiment, an example was given in which the ECU 4 is equipped with a power state management unit 43. However, for example, as shown in the communication system 300 of Modification 2 in Figure 10, the power state management unit 43 may be equipped in the ECU 5. In other words, the power state management unit 43 and the control unit 53 may be equipped in the same ECU. If the power state management unit 43 and the control unit 53 are equipped in different ECUs and communication between the ECUs becomes impossible, the control unit 53 will not be able to obtain management information from the power state management unit 43. However, according to the communication system 300 of Modification 2, since the power state management unit 43 and the control unit 53 are equipped in the same ECU, the control unit 53 can obtain management information from the power state management unit 43 without communication.

[0093] (2c) Alternatively, as shown in the communication system 400 of the modified example 3 in Figure 11, for example, the ECU 5 may include both a power supply switching unit and a power supply state management unit 43. Furthermore, the communication system may be equipped with multiple ECUs, each containing a control unit 53.

[0094] In the communication system 400, each control unit 53 controls a different power supply switching unit. For example, the control unit 53 of ECU 5 controls power supply switching units 61-63, the control unit 53 of ECU 5a controls power supply switching units 64-66, and the control unit 53 of ECU 5b controls power supply switching units 67-69. Whether power supply switching units 61-69 should transition to the ON state or the OFF state is centrally managed by the power state management unit 43 of ECU 5.

[0095] The power supply switching unit 61 is configured to switch between the on and off states in each power supply path between the battery 6 and the power supply switching units 64 to 66. The power supply switching unit 62 is configured to switch between the on and off states in the power supply path between the battery 6 and the ECU 1e. The power supply switching unit 63 is configured to switch between the on and off states in the power supply path between the battery 6 and the ECU 1d.

[0096] The power supply switching unit 64 is configured to switch between an on state and an off state in the power supply path between the battery 6 and the ECU 1a. The power supply switching unit 65 is configured to switch between an on state and an off state in the power supply path between the battery 6 and the ECU 1b. The power supply switching unit 66 is configured to switch between an on state and an off state in the power supply path between the battery 6 and the ECU 1c.

[0097] The power supply switching unit 67 is configured to switch between an on state and an off state in the power supply path between the battery 6 and the ECU 1f. Note that the ECUs corresponding to the power supply switching units 68 and 69 are not shown.

[0098] (2d) Each device (i.e., ECU1 to 5) and each method described herein may be implemented by a dedicated computer provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program. Alternatively, each device and each method described herein may be implemented by a dedicated computer provided by configuring a processor by one or more dedicated hardware logic circuits. Alternatively, each device and each method described herein may be implemented by one or more dedicated computers configured by a combination of a processor and memory programmed to perform one or more functions and a processor configured by one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by the computer on a computer-readable non-transitional tangible recording medium. The methods for implementing the functions of each part included in each device do not necessarily need to include software, and all of its functions may be implemented using one or more hardware components.

[0099] (2e) The functions of one component in the above embodiment may be distributed among multiple components, or the functions of multiple components may be integrated into one component. Also, some parts of the configuration of the above embodiment may be omitted. Also, at least some parts of the configuration of the above embodiment may be added to, replaced with, or otherwise adapted to the configuration of other above embodiments.

[0100] (2f) The present disclosure can be implemented in various forms, including, in addition to the above-mentioned in-vehicle device, a system that uses the in-vehicle device as a component, a program for causing the computer to function as the in-vehicle device, a medium on which the program is recorded, and a method for switching processes.

[0101] [Technical concepts disclosed in this specification] [Item 1] An in-vehicle device (5, 5a, 5b) used in an in-vehicle system (100, 200, 300, 400) equipped with multiple communication devices (1-3, 1a-1f), Each of the aforementioned communication devices is configured to receive power through its respective power supply path (21-23). Each of the aforementioned power supply paths is provided with a power supply switching unit (31-33, 61-69) configured to switch between an ON state that allows conductivity to the respective power supply path and an OFF state that blocks the respective power supply path. The in-vehicle device is A control unit (53) is configured to perform switching control to control whether to switch the power supply switching unit to the ON state or the OFF state, A communication unit (54) configured to communicate with the aforementioned plurality of communication devices, Equipped with, The control unit, when it receives a communication frame from a communication device corresponding to the power supply switching unit for which it has performed the switching control to transition to the off state, determines that the power supply switching unit is in a state of interruption failure, meaning it is unable to transition to the off state. An in-vehicle device, wherein the control unit performs the switching control to transition one of the power supply switching units to the off state, and the control unit determines that the first power supply switching unit is in the state of interruption failure, the communication unit transmits a stop frame, which is a communication frame instructing the communication device corresponding to the first power supply switching unit to stop the transmission process of transmitting a communication frame.

[0102] [Item 2] The in-vehicle device described in item 1, An in-vehicle device, wherein the control unit performs the switching control to transition the power supply switching unit 1 to the ON state, and the control unit determines that the power supply switching unit 1 is in the state of a circuit breaker failure, the communication unit transmits a start frame, which is a communication frame instructing the communication device corresponding to the power supply switching unit 1 to start the transmission process.

[0103] [Item 3] An in-vehicle device as described in item 1 or item 2, The in-vehicle device includes a power state management unit (43), The power supply state management unit is configured to manage whether the power supply switching unit should transition to the ON state or the OFF state according to the vehicle's driving state, and to notify the control unit of management information which indicates whether the power supply switching unit should transition to the ON state or the OFF state. The control unit is an in-vehicle device that performs the switching control in accordance with the management information notified by the power state management unit.

[0104] [Item 4] The in-vehicle device described in item 2, The plurality of communication devices include an abnormality detection unit (14) configured to perform communication abnormality detection to detect whether or not there is an abnormality in the communication state of the in-vehicle system. When the communication device corresponding to the power supply switching unit described in 1 receives the stop frame, it stops the transmission process and also stops the communication abnormality detection by the abnormality detection unit. The communication device corresponding to the power supply switching unit described in 1 above is an in-vehicle device that, upon receiving the start frame, starts the transmission process and also starts the communication abnormality detection by the abnormality detection unit.

[0105] [Item 5] An in-vehicle device described in any one of items 1 through 4, The aforementioned plurality of communication devices and the in-vehicle device are It has a wake-up state, which is the normal operating state, and a sleep state, which is a low-power operating state in which at least some of its functions are limited. The above-mentioned plurality of communication devices and the in-vehicle device are configured to transition to the sleep state if no communication request is received from any of the above-mentioned plurality of communication devices and the in-vehicle device.

[0106] [Item 6] The in-vehicle device described in item 2, The plurality of communication devices include an abnormality detection unit (14) configured to perform communication abnormality detection to detect whether or not there is an abnormality in the communication state of the in-vehicle system. Each of the aforementioned communication devices is capable of receiving not only the stop frames and start frames directed to itself, but also the stop frames and start frames directed to other communication devices. When the plurality of communication devices receive a communication frame from a communication device that has been instructed to stop the transmission process, they do not use the information of the communication frame for the abnormality detection unit to detect the communication abnormality. An in-vehicle device in which, when the plurality of communication devices receive a communication frame from a communication device that has been instructed to start the transmission process, the information of the communication frame is used by the anomaly detection unit to detect the communication anomaly.

[0107] [Item 7] An in-vehicle system (100, 200, 300, 400) is equipped with multiple communication devices (1-3, 1a-1f) and in-vehicle devices (5, 5a, 5b), Each of the aforementioned communication devices is configured to receive power through its respective power supply path (21-23). Each of the aforementioned power supply paths is provided with a power supply switching unit (31-33, 61-69) configured to switch between an ON state that allows conductivity to the respective power supply path and an OFF state that blocks the respective power supply path. The in-vehicle device is A control unit (53) is configured to perform switching control to control whether to switch the power supply switching unit to the ON state or the OFF state, A communication unit (54) configured to communicate with the aforementioned plurality of communication devices, Equipped with, The control unit, when it receives a communication frame from a communication device corresponding to the power supply switching unit for which it has performed the switching control to transition to the off state, determines that the power supply switching unit is in a state of interruption failure, meaning it is unable to transition to the off state. An in-vehicle system in which, when the control unit performs the switching control to transition one of the power supply switching units to the off state, and the control unit determines that the first power supply switching unit is in the state of interruption failure, the communication unit transmits a stop frame, which is a communication frame instructing the communication device corresponding to the first power supply switching unit to stop the transmission process of transmitting a communication frame. [Explanation of Symbols]

[0108] 1-3, 5, 1a-1f, 5a, 5b...ECU, 21-23...Power supply path, 31-33, 61-69...Power supply switching unit, 53...Control unit, 54...Communication unit, 61...Power supply switching unit, 100, 200, 300, 400...Communication system.

Claims

1. An in-vehicle device (5, 5a, 5b) used in an in-vehicle system (100, 200, 300, 400) equipped with multiple communication devices (1-3, 1a-1f), Each of the aforementioned communication devices is configured to receive power through its respective power supply path (21-23). Each of the aforementioned power supply paths is provided with a power supply switching unit (31-33, 61-69) configured to switch between an ON state that allows conductivity to the respective power supply path and an OFF state that blocks the respective power supply path. The in-vehicle device is A control unit (53) is configured to perform switching control to control whether to switch the power supply switching unit to the ON state or the OFF state, A communication unit (54) configured to communicate with the aforementioned plurality of communication devices, Equipped with, The control unit, when it receives a communication frame from a communication device corresponding to the power supply switching unit for which it has performed the switching control to transition to the off state, determines that the power supply switching unit is in a state of interruption failure, meaning it is unable to transition to the off state. An in-vehicle device, wherein the control unit performs the switching control to transition one of the power supply switching units to the off state, and the control unit determines that the first power supply switching unit is in the state of interruption failure, the communication unit transmits a stop frame, which is a communication frame instructing the communication device corresponding to the first power supply switching unit to stop the transmission process of transmitting a communication frame.

2. The in-vehicle device according to claim 1, An in-vehicle device, wherein the control unit performs the switching control to transition the power supply switching unit 1 to the ON state, and the control unit determines that the power supply switching unit 1 is in the state of a circuit breaker failure, the communication unit transmits a start frame, which is a communication frame instructing the communication device corresponding to the power supply switching unit 1 to start the transmission process.

3. An in-vehicle device according to claim 1 or claim 2, The in-vehicle device includes a power state management unit (43), The power supply state management unit is configured to manage whether the power supply switching unit should transition to the ON state or the OFF state according to the vehicle's driving state, and to notify the control unit of management information which indicates whether the power supply switching unit should transition to the ON state or the OFF state. The control unit is an in-vehicle device that performs the switching control in accordance with the management information notified by the power state management unit.

4. The in-vehicle device according to claim 2, The plurality of communication devices include an abnormality detection unit (14) configured to perform communication abnormality detection to detect whether or not there is an abnormality in the communication state of the in-vehicle system. When the communication device corresponding to the power supply switching unit described in 1 receives the stop frame, it stops the transmission process and also stops the communication abnormality detection by the abnormality detection unit. The communication device corresponding to the power supply switching unit described in item 1 is an in-vehicle device that, upon receiving the start frame, starts the transmission process and also starts the communication abnormality detection by the abnormality detection unit.

5. An in-vehicle device according to claim 1 or claim 2, The aforementioned plurality of communication devices and the in-vehicle device are It has a wake-up state, which is the normal operating state, and a sleep state, which is a low-power operating state in which at least some of its functions are limited. The above-mentioned plurality of communication devices and the in-vehicle device are configured to transition to the sleep state if no communication request is received from any of the above-mentioned plurality of communication devices and the in-vehicle device.

6. The in-vehicle device according to claim 2, The plurality of communication devices include an abnormality detection unit (14) configured to perform communication abnormality detection to detect whether or not there is an abnormality in the communication state of the in-vehicle system. Each of the aforementioned communication devices is capable of receiving not only the stop frames and start frames directed to itself, but also the stop frames and start frames directed to other communication devices. When the plurality of communication devices receive a communication frame from a communication device that has been instructed to stop the transmission process, they do not use the information of the communication frame for the abnormality detection unit to detect the communication abnormality. An in-vehicle device in which, when the plurality of communication devices receive a communication frame from a communication device that has been instructed to start the transmission process, the information of the communication frame is used by the anomaly detection unit to detect the communication anomaly.

7. An in-vehicle system (100, 200, 300, 400) is equipped with multiple communication devices (1-3, 1a-1f) and in-vehicle devices (5, 5a, 5b), Each of the aforementioned communication devices is configured to receive power through its respective power supply path (21-23). Each of the aforementioned power supply paths is provided with a power supply switching unit (31-33, 61-69) configured to switch between an ON state that allows conductivity to the respective power supply path and an OFF state that blocks the respective power supply path. The in-vehicle device is A control unit (53) is configured to perform switching control to control whether to switch the power supply switching unit to the ON state or the OFF state, A communication unit (54) configured to communicate with the aforementioned plurality of communication devices, Equipped with, The control unit, when it receives a communication frame from a communication device corresponding to the power supply switching unit for which it has performed the switching control to transition to the off state, determines that the power supply switching unit is in a state of interruption failure, meaning it is unable to transition to the off state. An in-vehicle system in which, when the control unit performs the switching control to transition one of the power supply switching units to the off state, and the control unit determines that the first power supply switching unit is in the state of a power interruption failure, the communication unit transmits a stop frame, which is a communication frame instructing the communication device corresponding to the first power supply switching unit to stop the transmission process of transmitting a communication frame.

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