JP2007001360A - Backup system of electronic control unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a backup system of an electronic control unit capable of coping with not only defects of LAN, but also defects of CPU of ECU. <P>SOLUTION: This backup system 10 of an electronic control unit of an automobile comprises a plurality of electronic control units (ECU). Each of the ECUs 20A-20C comprises a first CPU 21 for a normal operation, and a second CPU for backup. The first CPU 21 and the second CPU 22 are connected in parallel with a predetermined major load 50 and a major switch 51 for operating the major load 50. The first CPUs 21 installed to the electronic control units 20A-20C are connected with each other by a high-speed LAN 30, and the second CPUs 22 are connected with a low-speed LAN 40. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a backup system for an electronic control unit mounted on an automobile, and more particularly to a backup system for reliably operating a predetermined important load related to the safety of an automobile.

In recent years, electronic control units (ECUs) mounted on automobiles and wire harnesses connected to the electronic control units tend to increase, and securing these mounting spaces and increasing the weight and cost are problems. It has become.
In order to deal with such a problem, as shown in FIG. 4 (A), ECU 1A and ECU 1B, ECU 2A and ECU 2B provided close to each other are replaced with one ECU 1 and ECU 2 respectively as shown in FIG. 4 (B). It has been integrated in. Thereby, while reducing the number of ECUs, the electric wire which connected ECUs is abbreviate | omitted.
Further, the switch and the load 4 that need to be connected to the ECU 1A for communication are not directly connected by an electric wire as shown in FIG. 4A, but are arranged closer to the switch and the load 4 as shown in FIG. The switch 3 and the load 4 and the ECU 1 are communicatively connected via the ECU 3 and the LAN 5. This shortens the length of the wire harness.

As described above, by using the LAN for integration of the ECU and connection of the switch and load to the ECU, the number of ECUs can be reduced and the wire harness can be saved.
However, since the above-described configuration increases the dependence on the LAN, there is a wide range of effects when an abnormality occurs in the LAN.
Examples of the abnormality of the LAN include a failure of an electronic component (bus driver or the like) in the ECU connected to the LAN, a damage of a wire harness forming the LAN, and the like.

The above problem can be solved if the LAN configuration is a dual system so that even if an abnormality occurs in one LAN, the other LAN can be backed up. However, simply providing two LANs with the same configuration is expensive. In addition, there is a problem that when the CPU (calculation means) connected to the LAN in the ECU fails, both LANs cannot be used.
In addition, FlexRay, which is a standard for in-vehicle LAN, corresponds to the configuration of a dual system, but generally, both systems are controlled by a single CPU. It cannot be used with any other LAN.

  Furthermore, as another example of a backup system for an electronic control unit mounted on an automobile, as provided in Japanese Patent Application Laid-Open No. 2004-359060 (Patent Document 1), there are two systems: a wired system and a wireless system. Some systems communicate by providing a system, but in this case, there is a problem that communication apparatuses having different specifications must be provided.

JP 2004-359060 A

  The present invention has been made in view of the above problems, and not only an abnormality of a LAN connected to an electronic control unit mounted on an automobile but also an abnormality occurs in a calculation means (CPU) or the like in the electronic control unit. Another object of the present invention is to provide a backup system for an electronic control unit capable of operating an important load related to the safety of an automobile.

In order to solve the above problems, the present invention is a backup system for an electronic control unit in an automobile including a plurality of electronic control units,
Each electronic control unit includes a first calculation means and a second calculation means for backup of the first calculation means,
The first calculation means and the second calculation means are connected in parallel to a predetermined important load and an important operation means for operating the important load, while operating a general load other than the important load and the general load. The load operation means is connected only to the first calculation means,
The first calculation means provided in different electronic control units are connected to each other by a high-speed communication line, while the second calculation means provided to different electronic control units are connected to each other by a low-speed communication line. A backup system for electronic control units.

  The important load is a load related to the safety of the automobile, and examples thereof include a headlamp, a wiper, a stop lamp, a turn lamp, a hazard lamp, and a hack lamp.

According to the configuration of the present invention, since two first calculation means and second calculation means are provided in one electronic control unit, and the LAN is connected to each of them, the LAN connected to the first calculation means is connected to the LAN. Not only when an abnormality occurs but also when an abnormality occurs in the first calculation means itself, a predetermined important load can be controlled and operated by the second calculation means for backup.
On the other hand, the general load not related to the safety of the vehicle other than the important load and the operation means for the general load are connected only to the first calculation means and are not backed up by the second calculation means, but are not concerned with safety. Therefore, there is no significant influence, and the LAN connected to the second calculation means can be simplified and inexpensive.

Further, in the present invention, the first computing means is provided without connecting the LAN for connecting the first computing means provided in different electronic control units and the LAN for connecting the second computing means to a LAN composed of similar communication lines. While the LAN that connects the two is configured with a high-speed communication line, the LAN that connects the second computing means is configured with a low-speed communication line, so the cost is greatly increased by providing a backup system. Even if it is configured with a low-speed communication line, it can sufficiently cope with it.
The “high speed” of the communication line connected to the first calculation means and the “low speed” of the communication line connected to the second calculation means are speeds when the communication speeds of these communication lines are relatively compared, It means that the communication speed of the communication line connected to the first calculation means is higher than the communication speed of the communication line connected to the second calculation means.

It is preferable that the high-speed communication line connected to the first calculation unit is a FlexRay standard, while the backup low-speed communication line connected to the second calculation unit is a CAN standard or a LIN standard.
Alternatively, the high-speed communication line may be a CAN standard, while the backup low-speed communication line may be a LIN standard.

A power supply circuit for converting the voltage of the external power supply into the rating of the first calculation means or the second calculation means may be individually provided in the first calculation means and the second calculation means.
In this way, if the power supply circuit is provided separately for each of the first calculation means and the second calculation means, even if the power supply circuit of the first calculation means fails, the power supply circuit provided in the second calculation means Electric power can be supplied to operate the second computing means.
In other words, according to the above configuration, the second arithmetic unit can be operated and backed up regardless of which one of the first arithmetic unit, the LAN connected to the first arithmetic unit, and the power supply circuit fails. The communication system can be made high.
The power supply circuit includes a transistor, a resistor, a diode, a capacitor, and the like.

As described above, according to the present invention, two first calculation means and second calculation means are provided in one electronic control unit, and a communication line (LAN) is connected to each of them. Not only when an abnormality occurs in the communication line connected to, but also when an abnormality occurs in the first calculation means itself, the second calculation means for backup controls and operates an important load related to the safety of the vehicle. be able to.
In addition, a LAN that connects the first calculation means provided in different electronic control units is not a LAN that connects the first calculation means and a LAN that connects the second calculation means, but a LAN that connects the first calculation means. On the other hand, since the LAN connecting the second calculation means is configured with a low-speed communication line, the cost is not significantly increased by providing the backup system.

Embodiments of the present invention will be described with reference to the drawings.
1 and 2 show a first embodiment of the present invention, and FIG. 1 is a block diagram of a backup system 10 of an electronic control unit (hereinafter referred to as “ECU”) mounted on an automobile.
The plurality of ECUs 20A, 20B, and 20C are connected by a high-speed LAN 30 and a low-speed LAN 40, which are two different communication lines.
In the present embodiment, the high-speed LAN 30 is configured by “FlexRay” of a high-speed communication standard, and the low-speed LAN 40 is configured by “CAN” of a communication standard lower than the “FlexRay”.

Since the ECUs 20A to 20C have substantially the same configuration, the ECU 20A will be described as a representative with reference to FIG.
The ECU 20A includes first calculation means 21 (hereinafter referred to as “first CPU 21”) and backup second calculation means (hereinafter referred to as “second CPU 22”).
A high-speed LAN 30 is connected to the first CPU 21 via a first CPU bus driver 23 serving as an interface, and the first CPUs 21 of the ECUs 20A to 20C are connected to each other via the high-speed LAN 30.
On the other hand, the second CPU 22 is connected to a low-speed LAN 40 via a second CPU bus driver 24 serving as an interface, and the second CPUs 22 of the ECUs 20A to 20C are connected to each other via the low-speed LAN 40.

The first CPU 21 is connected to important loads 50 such as headlamps, wipers, stop lamps, turn lamps and the like related to vehicle safety, and an important switch 51 serving as an operation means for operating these important loads. . Further, a general load 60 such as a room light, a door lock, a washer, a drag mirror, or the like, which is not related to the safety of the automobile or less related to the safety of the vehicle, and a switch 61 serving as an operation means for operating the load 60 are connected. .
On the other hand, only the important load 50 and the important switch 51 for its operation are connected to the second CPU 22.

As described above, the first CPU 21 and the second CPU 22 are connected in parallel to the important load 50 and the important switch 51.
Further, an OR circuit 25 is interposed between the first and second CPUs 21 and 22 and the important load 50, and the OR circuit 25 receiving a signal from the first CPU 21 or the second CPU 22 transmits a required signal to the important load 50. It is configured.

  Further, a common power supply circuit 26 that converts the voltage of the external power supply into the rating of the first CPU 21 or the second CPU 22 is connected to the first CPU 21 and the second CPU 22. The power supply circuit 26 includes a transistor, a resistor, a diode, a capacitor, and the like.

In the backup system of the present invention configured as described above, during normal operation, the signal transmitted from the important switch 51 is input to the first CPU 21 and the second CPU 22 of the ECUs 20A to 20C and is calculated based on the signals received by the first CPU 21 and the second CPU 22. And perform judgment processing. A signal is transmitted from the first CPU 21 and the second CPU 22 to the OR circuit, and a signal from the first CPU is transmitted to the important load 50 to control the important load 50.
On the other hand, for example, when the first CPU 21 itself fails, the normally operating second CPU 22 receives and processes a signal from the important switch 51 and transmits a signal to the important load 50.
That is, when the first CPU 21 operates normally, the first CPU 21 is operated mainly, and signals from the important switch 51 and the switch 61 are received to control the important load 50 and the load 60. When the first CPU 21 fails, the control of the important load 50 can be backed up by the second CPU 22.

  Regarding the important load 50 and the important switch 61, since the first CPU 21 and the second CPU 22 are connected to the high-speed LAN 30 and the low-speed LAN 40, respectively, they operate normally even if the high-speed LAN 30 connected to the first CPU fails. It is connected to the second CPU via the low-speed LAN 40 and can communicate with other ECUs.

That is, the second CPU 22 receives a signal from the important switch 51 via the normally operating low-speed LAN 40 in both cases where the first CPU 21 itself fails and an abnormality occurs in the high-speed LAN 30 connected to the first CPU. Thus, the important load 50 can be controlled, and communication with other ECUs can be performed using the path of the low-speed LAN 40 via the bus driver 24 for the second CPU 22.
As described above, the first CPU 21 and the high-speed LAN 30 are mainly used in a normal state. However, when an abnormality occurs in the first CPU 21 and the high-speed LAN 30, the second CPU 22 and the low-speed LAN 40 are used for the important load 50 and the important switch 51. Thus, communication between the ECUs 20A to 20C can be backed up.

FIG. 3 shows a second embodiment of the present invention.
In the present embodiment, the power supply circuit is provided for each of the first CPU 21 and the second CPU 22. That is, a power supply line is branched upstream of the power supply circuit, and a first CPU power supply circuit 26A and a second CPU power supply circuit 26B are provided on the branch side, and are connected to the first and second CPUs 21 and 22, respectively.

  The high-speed LAN 30 connected to the first CPU 21 uses a CAN standard communication line, and the low-speed LAN 40 connected to the second CPU 22 uses a LIN standard communication line.

  According to the configuration, unlike the case where power is supplied to the two first and second CPUs 21 and 22 with a single power supply circuit, the two first and second CPUs 21 and 22 are provided with the power supply circuits 26A and 26B individually. Therefore, even if the first CPU power circuit 26A fails and the first CPU 21 cannot be used, the second CPU 22 can be operated by supplying power to the second CPU 22 by the second CPU power circuit 26B. Can be improved.

In both the first and second embodiments, the two first CPUs 21 and the second CPUs 22 are respectively provided in the electronic control units 20A to 20C, and the LAN is connected to each of them. Therefore, the high-speed LAN 30 connected to the first CPU 21 is provided. Even when an abnormality occurs in the first CPU 21 itself as well as when an abnormality occurs, the backup second CPU 22 can control and operate the predetermined important load 50.
Further, the LAN connecting the first CPUs 21 provided in the electronic control units 20A to 20C is the high-speed LAN 30, while the LAN connecting the second CPUs 22 for backup is the low-speed LAN 40. The cost will not increase.

It is a block diagram of the backup system of the electronic control unit of 1st Embodiment of this invention. It is the block diagram which showed schematic structure and the example of connection of ECU. It is the block diagram which showed schematic structure and the example of connection of ECU of 2nd Embodiment. (A) and (B) are block diagrams showing an example of connection between conventional ECUs.

Explanation of symbols

10 Electronic Control Unit Backup System 20A, 20B, 20C Electronic Control Unit (ECU)
21 First CPU
22 Second CPU
23 Bus driver for first CPU 24 Bus driver for second CPU 25 OR circuit 26 Power supply circuit 30 High-speed LAN
40 Low speed LAN
50 Important load 51 Important switch 60 Load 61 Switch

Claims (4)

A backup system for an electronic control unit in an automobile having a plurality of electronic control units,
Each electronic control unit includes a first calculation means and a second calculation means for backup of the first calculation means,
The first calculation means and the second calculation means are connected in parallel to a predetermined important load and an important operation means for operating the important load, while operating a general load other than the important load and the general load. The load operation means is connected only to the first calculation means,
The first calculation means provided in different electronic control units are connected to each other by a high-speed communication line, while the second calculation means provided to different electronic control units are connected to each other by a low-speed communication line. Backup system for electronic control unit. The high-speed communication line is a FlexRay standard and the low-speed communication line is a CAN standard or a LIN standard, or
2. The electronic control unit backup system according to claim 1, wherein the high-speed communication line is a CAN standard and the low-speed communication line is a LIN standard.   The power supply circuit which converts the voltage of an external power supply into the rating of a 1st calculating means or a 2nd calculating means is each provided in the said 1st calculating means and the 2nd calculating means separately, respectively. Electronic control unit backup system.   The electronic control unit according to any one of claims 1 to 3, wherein the important load is a load related to safety of the vehicle such as a headlamp, a wiper, a stop lamp, a turn lamp, a hazard lamp, and a pack lamp. Backup system.

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