JP2008259124A - On-vehicle communication system and electronic control unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an on-vehicle communication system and an electronic control unit which can transmit and receive communication data between buses even when abnormality occurs in a gateway apparatus, without increasing cost. <P>SOLUTION: In the on-vehicle communication system 10 with which a communication data mediation device 14 mediates communication data A from a first communication bus 11 to a second communication bus 12, an electronic control unit 13B for processing communication data A connected to the first communication bus 11 and the second communication bus 12 is provided with an abnormality detection means 15 for detecting abnormality of the communication data mediation device 14, a substituting means 16 for executing the function instead of the communication data mediation device when the abnormality detection means detects abnormality, and a processing control means 17 for stopping processing for communication data or controlling processing when the abnormality detection means detects abnormality. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an in-vehicle communication system and an electronic control unit, and particularly to an in-vehicle communication system and an electronic control unit that mediate communication data from a first communication bus to a second communication bus.

  Various types of sensors are mounted on the vehicle, and on-vehicle devices such as driving support and travel control based on signals detected by the sensors are controlled. For this control, a plurality of electronic control units (ECUs) suitable for objects to be controlled and signal processing are mounted, and other ECUs use signals detected by sensors and data processed by certain ECUs. In many cases, it is necessary to share signals and data (hereinafter simply referred to as communication data) between ECUs.

  For this reason, each ECU is connected to the in-vehicle LAN, the communication data is distributed on the in-vehicle LAN, and the communication data is shared by the ECUs extracting necessary communication data.

  By the way, such an in-vehicle LAN includes, for example, a control system that connects control devices that control engines, automatic transmissions, brakes, and the like, a body system that connects control devices that control door locking / unlocking, air conditioning devices, and the like. In many cases, the various controls mounted on the vehicle are classified according to function / system, and are constructed for each group, that is, across a plurality of buses. In addition, since there may be an upper limit on the number of ECUs that can be connected to one bus of the in-vehicle LAN, the in-vehicle LAN is constructed over a plurality of buses in accordance with this request.

  However, since the ECUs connected to different buses may require the same communication data, a gateway device having a communication data relay function is connected to each system bus, and the common communication data is sent to each bus. You can send and receive between them.

For this reason, when a failure or the like of the gateway device occurs, there is a problem that communication data cannot be transmitted from one bus to the other bus, and the ECU of another bus cannot share the communication data. Therefore, in order to improve the reliability of connection between the buses, when a transmission / reception failure occurs in any ECU connected to the two buses, communication between the buses is performed by another ECU connected to the two buses. A vehicle communication system that transmits and receives data has been proposed (see, for example, Patent Document 1). According to the vehicle communication system described in Patent Document 1, when an ECU connected to two buses has a gateway function and the ECU cannot transmit and receive communication data, the other ECU is connected from one bus to the other. Send / receive communication data to / from the bus.
JP 2006-333007 A

  However, in the vehicle communication system described in Patent Document 1, since the ECU connected to the two buses has a gateway function, there is a problem that the processing load of the ECU increases. In general, ECUs often have a small processing capacity due to cost and in-vehicle space constraints, and it is difficult to request processing as a gateway in addition to control of in-vehicle devices. In other words, because of the function as a gateway, a design with a margin for processing capacity increases costs.

  In view of the above problems, an object of the present invention is to provide an in-vehicle communication system and an electronic control unit that enable transmission and reception of communication data between buses even when an abnormality occurs in a gateway device without increasing costs. .

  In view of the above problems, according to the present invention, a communication data mediating device (for example, gateway device 14) mediates communication data from a first communication bus (for example, bus 11) to a second communication bus (for example, bus 12). In the in-vehicle communication system, an electronic control unit (e.g., ECU 13B) that processes communication data connected to the first communication bus and the second communication bus detects an abnormality in the communication data mediating device (e.g., an abnormality detection unit). If the gateway abnormality detecting means 15) and the abnormality detecting means detect an abnormality, the proxy means (for example, the gateway proxy means 16) acting on behalf of the function of the communication data mediating apparatus and the abnormality detecting means detect the abnormality And processing restriction means for stopping the data processing or restricting the processing.

  According to the present invention, since the electronic control unit that stops processing of communication data or restricts processing substitutes for the function of the communication data mediating apparatus, it is not necessary to provide a margin for processing of the electronic control unit and increase costs. It is possible to cope with the abnormality of the gateway device without doing so.

  In one embodiment of the present invention, the electronic control unit executes processing related to driving support such as safe driving and comfortable driving of the vehicle.

  According to the present invention, the electronic control unit acting on behalf of the communication data mediating apparatus mediates the communication data while minimizing the functional deterioration related to traveling without disabling the traveling even if the processing is stopped or restricted. be able to.

  An object of the present invention is to provide an in-vehicle communication system and an electronic control unit that can transmit and receive communication data between buses even if an abnormality occurs in a gateway device without increasing costs.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 shows an example of a configuration diagram of an in-vehicle communication system 10. The ECU 13A, which is an electronic control unit (hereinafter referred to as ECU), is connected to the bus 11, the ECU 13C is connected to the bus 12, and the gateway device 14 and the ECU 13B are connected to both the two buses 11 and 12. The ECU 13B connected to both of the two buses 11 and 12 can perform a low-priority process, for example, if the control is performed, allows comfortable driving, improves riding comfort, and provides safer driving assistance. It is an electronic control unit that performs processing that becomes possible. In the vehicle communication system 10 according to the present embodiment, when any abnormality occurs in the gateway device 14, the ECU 13 </ b> B stops or restricts the low-priority processing and performs the relay of the communication data A instead of the gateway device 14. Since the ECU 13B is not added due to an abnormality in the gateway, the abnormality of the gateway device 14 can be dealt with without increasing the cost.

  The ECUs 13A, 13B, and 13C have different in-vehicle devices and functions to be controlled, but all have a CPU that executes a program, a work area for program execution, and a memory (RAM) that temporarily stores data, a boot program, and a BIOS. This is a computer in which a ROM that stores data, a memory that stores programs and files, and an input / output unit that inputs and outputs data via buses 11 and 12 are connected via an internal bus.

  The ECU 13B limits the gateway low-priority detection unit 15 that detects a failure of the gateway device 14, the gateway proxy unit 16 that performs the function of the gateway device 14, and low-priority processing, which is realized by the CPU executing the program. The process restriction means 17 is provided.

  The buses 11 and 12 electrically connect the ECUs 13A, 13B, and 13C, and configure an in-vehicle LAN based on a predetermined protocol (for example, a CAN (Controller Area Network) protocol, a LIN (Local Interconnect Network) protocol, or the like). The protocol can be determined for each of the buses 11 and 12, and the protocol of the bus 11 and the bus 12 may be the same or different.

  For example, the CAN protocol is a communication protocol having high-speed communication up to 1 Mbps, bus access control by a multi-master system, a bus-off function at the time of transmission abnormality, and the like, and the following data format “SOF; arbitration field; control field; data field; The communication data A is sent to the buses 11 and 12 with the CRC field; ACK field; EOF "as one frame.

  SOF is an area for storing a bit indicating the start of a CAN frame, an arbitration field is an area for storing an ID number for identifying the frame, a control field is an area for storing a data length, and a data field is an area for storing data ( (0 to 8 bytes), the CRC field is an area for storing a code for error check, the ACK field is an area for transmitting that data is received by the ECU, and EOF is an area for storing a bit string indicating the end of the frame.

  The communication data A on the buses 11 and 12 is assigned a unique number for determining a priority order called ID (the lower the ID, the higher the priority order), and each ECU 13A to 13C receives the reference by referring to this ID. Determine whether or not.

  Similarly, the gateway device 14 is also configured as a computer, and the CPU executes the program to mediate the communication data A between the buses 11 and 12. The gateway device 14 divides the in-vehicle communication system 10 into a plurality of networks, thereby reducing the load caused by the wiring length of the buses 11 and 12 and the communication amount of the communication data A. The gateway device 14 mediates the communication data A from one bus 11 (12) to the other bus 12 (11) according to the filtering rule and the conversion rule. When mediating the communication data A to a bus of another protocol, the gateway device 14 converts the protocol.

  For example, the gateway device 14 stores a data list of communication data A to be mediated from one connected bus 11 (12) to the other bus 12 (11), and the other is based on the frame ID and the data list. The communication data A that mediates to the bus 12 (11) is selected.

  Therefore, for example, when the ECU 13A sends the communication data A to the bus 11, the communication data A circulates on the bus 11, and the gateway device 14 distributes the communication data A to the bus 12 via the communication data A. . As a result, the ECU 13A and the ECU 13C can share the communication data A.

  The ECUs 13A to 13C may be any ECU. For example, in the case of a body-based in-vehicle LAN, they are an air conditioner ECU, a meter ECU, a body ECU, a verification ECU, and the like. The air conditioner ECU controls the air temperature, discharge port, air volume, etc. of the air conditioner mounted on the vehicle, and the meter ECU controls various vehicle conditions such as vehicle speed, engine speed, door open / close state, transmission shift range, etc. Is displayed on the instrument panel in front of the driver's seat, and the body ECU controls the locking / unlocking of the door in cooperation with the keyless entry system and the verification ECU. When authentication is established through communication, the body ECU is instructed to lock / unlock the door, or the engine is allowed to start.

  For example, when the ECU 13A is a meter ECU and the ECU 13C is a body ECU, the gateway device 14 mediates the flow (wheel speed data) detected by the wheel speed sensor and sent out to the buses 11 and 12 through the predetermined ECU. . In this case, the communication data A may be mediated from the bus 11 or from the bus 12. The meter ECU displays a speed meter on the instrument panel according to the wheel speed data, and the body ECU automatically locks the door when the vehicle speed is greater than or equal to a predetermined value. The ECU 13B is an ECU that is connected to either of the two buses 11 and 12 to which the gateway device 14 is connected, and is an ECU that executes processing with a relatively low priority, for example, a verification ECU.

  In the case of a control-system in-vehicle LAN, the ECUs 13A to 13C are an engine ECU, an ESC (electronic stability control) ECU, an air suspension ECU, an LKA (Lane Keeping Assist) ECU, an ACC (Adaptive Cruise Control) ECU, and the like. The engine ECU is for controlling the rotational speed and fuel injection amount of the engine, which is the power source of the vehicle, and the ESC / ECU is for posture control by preventing side slip such as oversteer and understeer of the vehicle, The air suspension ECU controls the air pressure of the air suspension to adjust the vehicle height, roll, and riding comfort. The LKA / ECU performs steering control based on the white line information that is the recognition result of the white line that divides the traveling lane, The ACC / ECU cooperates with the engine ECU or the like to travel following a constant speed or preceding vehicle.

  For example, when the ECU 13A is an ACC / ECU and the ECU 13C is an LKA / ECU, the gateway device 14 mediates communication data (wheel speed data) A detected by a wheel speed sensor and transmitted by a predetermined ECU. , 12 to drain. When traveling at a constant speed, the ACC / ECU requests the engine ECU to control the throttle opening degree according to the wheel speed data, and the LKA / ECU variably controls the alarm timing according to the vehicle speed. The ECU 13B is an ECU that is connected to either of the two buses 11 and 12 to which the gateway device 14 is connected, and is an ECU that executes processing with relatively low priority, for example, an ESC / ECU.

  As described above, the ECU 13B is an ECU that uses the communication data A distributed to the two buses 11 and 12 without being influenced by the ECU 13A and the ECU 13C, and corresponds to an ECU that executes a process with low priority. Since the ECU executes a process with low priority, the vehicle can travel even if the ECU 13B stops the process. Therefore, when an abnormality occurs in the gateway device 14, the ECU 13B can substitute for the gateway function.

  Since the ECU 13B is connected to the two buses 11 and 12, the gateway abnormality detection means 15 monitors the communication data A distributed in common to the two buses 11 and 12 via the gateway device 14, and the bus 11 or When the communication data A is distributed only to any one of 12, the abnormality of the gateway device 14 is detected.

  Instead of the gateway device 14, the gateway agent 16 replaces the one bus 11 (12) with the other bus 12 in accordance with the data list, filtering rule or conversion rule of the communication data A to be mediated through the two buses 11, 12. The communication data A is mediated in (11), and the protocol is converted if necessary.

  When the ECU 13B performs the gateway function, the process restriction unit 17 stops the low-priority process executed by the ECU 13B until then, or continues the process after limiting the process (hereinafter simply referred to as processing load). Called limit). Since the processing load assigned to the original processing of the ECU 13B is limited, it is not necessary to provide a margin for the processing load of the ECU 13B and the cost is not increased.

  Since the ECU 13B preferentially executes the proxy function of the gateway function, the process restriction unit 17 monitors, for example, the CPU load factor of the ECU 13B and determines how much the process load is restricted according to the CPU load factor. For example, the setting defines that the low priority processing that is the original processing is permitted only when the CPU load factor is equal to or less than a predetermined threshold. If this threshold value is set low, the processing executed by the ECU 13B is stopped, and if this threshold value is set high, the processing executed by the ECU 13B is executed only when the processing load acting on behalf of the gateway function is small. Will be able to.

  In addition, when the ECU 13B is performing a plurality of processes that can be separated into several, the process restriction unit 17 may stop the process with the lower priority. For example, in the case of an ESC / ECU, ABS (Anti-Lock Brake System) control with a processing load smaller than that of the ESC is also possible. Therefore, the processing load can be limited by executing only the ABS control in the ESC control.

  FIG. 2 is a flowchart showing a procedure in which the ECU 13B performs the gateway function when an abnormality occurs in the gateway device 14. The flowchart of FIG. 2 is repeatedly executed at predetermined cycle times after the ignition is turned on, for example.

The gateway abnormality detection means 15 determines whether or not an abnormality of the gateway device 14 is detected depending on whether or not the communication data A is distributed to the two buses 11 and 12 (S10). For example, the detection may be performed when communication with the gateway device 14 becomes impossible. If no abnormality is detected, the process is terminated and repeated every cycle time.
When an abnormality is detected in the gateway device 14 (Yes in S10), the gateway agent means 16 substitutes for the function of the gateway device 14 (S20), and the processing restriction means 17 allows the gateway function to be preferentially substituted for the gateway function. The processing load is limited for low priority processing.

  FIG. 3 shows an example of a configuration diagram of the in-vehicle communication system 10 in which the ECU 13B performs the gateway function. In FIG. 3, the same components as those in FIG. As shown in FIG. 3, even if an abnormality occurs in the gateway device 14, the communication data A can be distributed to the buses 11 and 12 because the ECU 13 </ b> B performs the gateway function. Further, since the ECU 13B executes a process with a low priority, even if the process is stopped, at least traveling is possible, and it is not necessary to provide a margin for the process in the ECU 13B, so there is no increase in cost. .

It is an example of the block diagram of a vehicle-mounted communication system. It is a flowchart figure which shows the procedure in which ECU13B substitutes for a gateway function when abnormality arises in a gateway apparatus. It is an example of the block diagram of the vehicle-mounted communication system in which ECU13B performed the gateway function.

Explanation of symbols

10 On-vehicle communication system 11, 12 Bus 13 Electronic control unit (ECU)
DESCRIPTION OF SYMBOLS 14 Gateway apparatus 15 Gateway abnormality detection means 16 Gateway proxy means 17 Processing restriction means

Claims (3)

In the in-vehicle communication system in which the communication data mediating device mediates communication data from the first communication bus to the second communication bus.
An electronic control unit for processing the communication data connected to the first communication bus and the second communication bus;
An abnormality detecting means for detecting an abnormality of the communication data mediating device;
If the abnormality detecting means detects an abnormality, a proxy means acting on behalf of the function of the communication data mediating device;
When the abnormality detection unit detects an abnormality, the processing of the communication data is stopped or a processing restriction unit that restricts the processing is included.
The in-vehicle communication system according to claim 1. The electronic control unit executes processing related to driving support such as safe driving and comfortable driving of a vehicle,
The in-vehicle communication system according to claim 1. In an electronic control unit connected to the first communication bus and the second communication bus,
An abnormality detecting means for detecting an abnormality of the communication data mediating apparatus that mediates communication data from the first communication bus to the second communication bus;
If the abnormality detecting means detects an abnormality, a proxy means acting on behalf of the function of the communication data mediating device;
When the abnormality detection means detects an abnormality, processing restriction means for stopping the processing of the communication data or restricting the processing;
An electronic control unit comprising:

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