JP7050154B2 - Electronic control device - Google Patents

Description

The present invention relates to an electronic control device that controls an electric device mounted on a vehicle.

The electronic control device mounted on the vehicle carries out a control calculation for controlling the electrical equipment mounted on the vehicle. Each electronic control device may transmit and receive data necessary for control calculation by communicating with each other via an in-vehicle network mounted on the vehicle. The in-vehicle network and the electronic control device are connected via a communication device included in the electronic control device (for example, a CAN transceiver in the case of a CAN (Control Area Network) network).

The following Patent Document 1 describes an electronic control device mounted on a vehicle. In the same document, when the functional computer fails, the connection unit (CAN transceiver) is deactivated to prevent the failed functional computer from transmitting a signal to the CAN network. In the technique described in the same document, the monitoring unit monitors the error of the functional unit, and when the error is detected, the monitoring unit outputs an error signal to the reset input (RST) of the connection unit. When the connection unit receives an error signal at the reset input, it shifts to the inactive mode.

Special Table 2005-535054

The CAN transceiver includes a terminal called a MODE terminal or the like as a terminal having the same role as the reset input in Patent Document 1. The arithmetic unit can switch the active mode / listen-only mode of the CAN transceiver by outputting a signal for switching the operation mode of the CAN transceiver to the MODE terminal.

On the other hand, with the recent electrification of vehicles, the adoption of highly functional communication devices (for example, partial network CAN transceivers) is being considered in order to reduce power consumption and extend the continuous cruising distance. As the communication device becomes more sophisticated, the terminal corresponding to the above-mentioned MODE terminal may be omitted. This is because the mounting area can be reduced or terminals for other functions can be provided by omitting the MODE terminal.

When the arithmetic unit is operating abnormally, it is desirable to switch the communication device to the receive-only mode so that the abnormal data is not transmitted to the in-vehicle network. However, when using a communication device that does not have a MODE terminal as described above, there is no direct means for switching the communication device to the receive-only mode.

The present invention has been made in view of the above problems, and even in an electronic control device using a communication device that does not have a terminal for inputting a signal for switching to the receive-only mode, the arithmetic unit operates abnormally. The purpose is to prevent the communication device from sending data to the communication network when it is.

In the electronic control device according to the present invention, the communication device is configured not to transmit a signal to the communication network while continuously receiving a signal of a predetermined signal level from the arithmetic device, and the monitoring device is described as described above. When the arithmetic unit is not operating normally, the signal output by the arithmetic apparatus is overwritten on the signal of the predetermined signal level to prevent the communication device from transmitting the signal to the communication network.

According to the electronic control device according to the present invention, even when a communication device not provided with a terminal for inputting a signal for switching to the reception mode is used, the arithmetic unit operating abnormally signals the in-vehicle network. Can be prevented from being sent.

It is a functional block diagram of the electronic control device 100 which concerns on Embodiment 1. FIG. This is a configuration example of the transmission control circuit 30. It is a block diagram of the electronic control apparatus 100 which concerns on Embodiment 2. FIG. It is a block diagram of the electronic control apparatus 100 which concerns on Embodiment 3. FIG. It is a block diagram of the electronic control apparatus 100 which concerns on Embodiment 4. FIG.

<Embodiment 1: Device Configuration>
FIG. 1 is a functional block diagram of the electronic control device 100 according to the first embodiment of the present invention. The electronic control device 100 is mounted on a vehicle and executes a control calculation for controlling an electric device included in the vehicle. The electronic control device 100 is a device such as an engine control device, a transmission control device, a brake control device, a battery control device, a motor control device, and a hybrid control device.

The electronic control device 100 can communicate with another control device 200 via the bus wiring 300. For example, CAN can be used as the communication protocol. In the CAN network, when a plurality of signals exist on the bus wiring 300, the device that emits the signal having the highest priority among the signals becomes the transmitting side, and the other device becomes the receiving side. This point will be described in detail later.

The electronic control device 100 includes an arithmetic unit 10, a monitoring device 20, a transmission control circuit 30, and a communication device 40. The arithmetic unit 10 is an apparatus that executes control operations, and transmits / receives signals via the bus wiring 300. The monitoring device 20 receives an output from the arithmetic unit 10 via the communication wiring 11 and monitors whether or not the arithmetic unit 10 is operating normally by using the output. The transmission control circuit 30 will be described later. The communication device 40 is, for example, a CAN transceiver and functions as a communication interface between the electronic control device 100 and the bus wiring 300.

A communication wiring 11 is connected to the output terminal of the arithmetic unit 10 and is electrically connected to the monitoring device 20. The arithmetic unit 10 includes a transmission terminal for outputting a signal to be transmitted via the bus wiring 300. A communication wiring 12 extends from the transmission terminal of the arithmetic unit 10 and is connected to the transmission control circuit 30. The information fixed wiring 21 extending from the monitoring device 20 is input to the transmission control circuit 30. The transmission control circuit 30 receives the signal output by the arithmetic unit 10 and outputs it to the communication device 40 via the transmission wiring 31. The communication device 40 and the bus wiring 300 are electrically connected via the input / output wiring 42. The signal received by the communication device 40 from the bus wiring 300 is input to the arithmetic unit 10 via the reception wiring 41.

<Embodiment 1: Principle of transmission restriction>
The communication device 40 can switch between a mode in which both data transmission / reception can be performed and a reception-only mode. However, it is assumed that the communication device 40 does not have a terminal for inputting a signal for instructing the mode switching. In the first embodiment, even in that case, it is attempted to prevent the communication device 40 from transmitting data to the bus wiring 300 in the event of an abnormality in the arithmetic unit 10. The principle of transmission restriction will be described below.

In the CAN protocol, the bus wiring 300 transmits a differential signal. If both lines have substantially the same voltage, the data on the bus wiring 300 represents a bit value 1, and if there is a voltage difference between the two lines (or if it is sufficiently large), it represents a bit value 0. A bit value of 1 is called a recessive bit, and a bit value of 0 is called a dominant bit. When different nodes output the recessive bit and the dominant bit to the bus wiring 300 at the same time, the data on the bus wiring 300 becomes the dominant bit. Therefore, the bus wiring 300 becomes a recessive bit only when all the nodes on the bus wiring 300 are driving the recessive bit. Each node on the bus wiring 300 uses this characteristic to check whether the bit value on the bus wiring 300 and the bit value transmitted by itself are the same. If they are the same, the next bit value is driven, and if they are different, the transmission is stopped and the mode shifts to the mode of receiving the data on the bus wiring 300. The operation mode of this reception state is called a listen-only mode or the like.

According to the above mechanism in the CAN protocol, the following can be said. (A) When the communication device 40 is trying to output the recessive bit, if the bus wiring 300 is also the recessive bit, it is not necessary for the communication device 40 to further output the recessive bit. Therefore, at this time, it can be considered that the communication device 40 does not substantially transmit data to the bus wiring 300.
(B) When the communication device 40 is about to output the recessive bit, if the bus wiring 300 is the dominant bit, the communication device 40 shifts to the listen-only mode. Therefore, at this time, the communication device 40 does not transmit data to the bus wiring 300.

According to the above examination, in order to prevent the communication device 40 from transmitting data to the bus wiring 300, a recessive bit is given to the communication device 40 as data to be transmitted from the arithmetic unit 10 to the bus wiring 300. You just have to continue. Thereby, even when the communication device 40 does not have the MODE terminal, it is possible to create a pseudo state in which data is not transmitted from the communication device 40 to the bus wiring 300. The monitoring device 20 and the transmission control circuit 30 utilize this principle to prevent the communication device 40 from transmitting data to the bus wiring 300 when the arithmetic unit 10 is abnormal.

<Embodiment 1: Specific circuit configuration example>
FIG. 2 is a configuration example of the transmission control circuit 30. The monitoring device 20 can be configured as, for example, a watchdog timer. In this case, the arithmetic unit 10 periodically resets the timer of the monitoring device 20 via the communication wiring 11. When the timer is not reset, the monitoring device 20 outputs a signal to that effect via the information fixed wiring 21. This signal indicates that the arithmetic unit 10 is abnormal. For example, when the arithmetic unit 10 is normal, the information fixed wiring 21 is set to a high level, and when it is abnormal, the information fixed wiring 21 is set to a low level.

The transmission control circuit 30 includes a logical sum circuit. The OR circuit obtains the OR of the output of the arithmetic unit 10 and the signal representing the operating state of the arithmetic unit 10. FIG. 2 is a configuration example in which the communication wiring 33 is at a high level when the arithmetic unit 10 is abnormal. As a result, when the arithmetic unit 10 is abnormal, the communication wiring 32, which is the output of the disjunction circuit, is always overwritten and fixed at a high level regardless of the output from the arithmetic unit 10. A damping resistor may be added to the output of the disjunction circuit to suppress signal resonance.

The communication device 40 does not transmit data to the bus wiring 300 according to the above principle while the high level signal continues to be given through the transmission wiring 31. Therefore, while the arithmetic unit 10 is abnormal, it is in the same state as the data transmission from the arithmetic unit 10 to the bus wiring 300 is prohibited. As a result, even if the communication device 40 does not have a MODE terminal, it is possible to create substantially the same state as in the listen-only mode.

<Embodiment 2>
FIG. 3 is a block diagram of the electronic control device 100 according to the second embodiment of the present invention. The configuration of the transmission control circuit 30 is different from that of the first embodiment. Since other configurations are the same as those in the first embodiment, the differences will be mainly described below.

The transmission control circuit 30 switches whether or not to connect an internal power supply (for example, a voltage provided in the electronic control device 100 and corresponding to a high level of the output of the arithmetic unit 10) to the transmission wiring 31. It is equipped with a switching element. The switching element included in the transmission control circuit 30 can be configured by, for example, a P-channel field effect transistor or a PNP bipolar transistor. A current limiting resistor may be attached to the output of the arithmetic unit 10. This can be used to limit the excessive current from flowing into the arithmetic unit 10 via the switching element when the output of the arithmetic unit 10 is at a low level. If this resistance is made too large, the cutoff frequency of the low-pass filter composed of the capacitive components of the switching element and the substrate pattern will decrease, the signal waveform input to the transmitter 40 will be greatly blunted, and high-speed data transmission above a certain level will be possible. Therefore, it is necessary to adopt an appropriate resistance value.

The monitoring device 20 outputs a low level from the information fixed wiring 21 when the arithmetic unit 10 is abnormal. As a result, the switching element becomes conductive, and the voltage of the internal power supply is applied to the transmission wiring 31. That is, since a high-level signal is given to the communication device 40 via the transmission wiring 31, the communication device 40 does not transmit data to the bus wiring 300 as in the first embodiment. Thereby, the same operation as that of the first embodiment can be implemented.

<Embodiment 3>
In the first and second embodiments, the communication device 40 does not transmit data to the bus wiring 300 (or substantially this) by continuously giving the recessive bit to the communication device 40 while the arithmetic unit 10 is abnormal. (Can be equated with) explained to create a state. Apart from this, it is also conceivable to forcibly activate the listen-only mode included in the communication device 40 so that the communication device 40 does not transmit data to the bus wiring 300. In the third embodiment of the present invention, a configuration example for that purpose will be described.

<Embodiment 3: Principle of transmission restriction>
The communication device 40 has an operation mode for transmitting and receiving signals to and from the bus wiring 300, and a reception-only mode (listening) in which signals can be received from the bus wiring 300 but cannot be transmitted to the bus wiring 300. Only mode) can be switched. However, there is no terminal for inputting a signal for switching the operation mode of the communication device 40. On the other hand, the communication device 40 has a function of shifting to the listen-only mode by itself when a predetermined condition is met. This function will be described.

As described in the first embodiment, when the communication device 40 outputs the dominant bit, the bus wiring 300 is occupied. However, it is not desirable that the bus wiring 300 is continuously occupied for a long time, and it is possible that some abnormality has occurred in such a state. Therefore, the communication device 40 has a function of shifting to the listen-only mode by itself when the dominant bit is continuously given as the data to be transmitted to the bus wiring 300 for a predetermined time or longer. This makes it possible to prevent the bus wiring 300 from being continuously occupied.

Therefore, in order to shift the communication device 40 to the listen-only mode, the dominant bit may be continuously given to the bus wiring 300 as data to be transmitted for a predetermined time or longer. The monitoring device 20 and the transmission control circuit 30 utilize this principle to prevent the communication device 40 from transmitting data to the bus wiring 300 when the arithmetic unit 10 is out of order.

<Embodiment 3: Specific circuit configuration example>
FIG. 4 is a configuration diagram of the electronic control device 100 according to the third embodiment. The configuration of the transmission control circuit 30 is different from that of the first and second embodiments. Since other configurations are the same as those of the first and second embodiments, the differences will be mainly described below.

The transmission control circuit 30 includes a logical product circuit. The logical product circuit obtains the logical product of the output of the arithmetic unit 10 and the signal representing the operating state of the arithmetic unit 10. FIG. 4 is a configuration example in which the information fixed wiring 21 is at a low level when the arithmetic unit 10 is abnormal. As a result, when the arithmetic unit 10 is abnormal, the communication wiring 32, which is the output of the AND circuit, is always overwritten and fixed at a low level regardless of the output from the arithmetic unit 10. Similar to the first embodiment, a damping resistor for suppressing signal resonance may be added to the output of the AND circuit.

When the communication device 40 continues to be given a low-level signal (that is, dominant bit) for a predetermined time or longer via the transmission wiring 31, the communication device 40 shifts to the listen-only mode by the above function. Therefore, when the monitoring device 20 determines that the arithmetic unit 10 is abnormal, the communication device 40 shifts to the listen-only mode, so that the arithmetic unit 10 does not send the abnormal data to the bus wiring 300. not. As a result, even if the communication device 40 does not have the MODE terminal, the communication device 40 can be forcibly shifted to the listen-only mode.

<Embodiment 4>
FIG. 5 is a block diagram of the electronic control device 100 according to the fourth embodiment of the present invention. The configuration of the transmission control circuit 30 is different from that of the third embodiment. Since other configurations are the same as those in the third embodiment, the differences will be mainly described below.

The transmission control circuit 30 includes a switching element that switches whether or not to connect the ground potential to the transmission wiring 31. The switching element included in the transmission control circuit 30 can be configured by, for example, an N-channel field effect transistor or an NPN bipolar transistor. Similar to the second embodiment, a current limiting resistor may be attached to the output of the arithmetic unit 10.

The monitoring device 20 outputs a high level from the information fixed wiring 21 when the arithmetic unit 10 is abnormal. As a result, the switching element becomes conductive and the ground potential is applied to the transmission wiring 31. That is, since a low-level signal is given to the communication device 40 via the transmission wiring 31, the communication device 40 shifts to the listen-only mode as in the third embodiment. Thereby, the same operation as that of the third embodiment can be implemented.

<About a modification of the present invention>
In the above embodiment, the example in which the electronic control device 100 communicates with another device via the bus wiring 300 using the CAN protocol has been described, but the communication protocol to which the present invention can be implemented is not limited to CAN. For example, the LIN (Local Interconnect Network) protocol can be used. That is, the same method as the present invention can be applied as long as it is a communication device that does not transmit data to the in-vehicle network while continuously receiving a predetermined signal level as a signal to be transmitted to the in-vehicle network. ..

In the above embodiment, the example of using the watchdog timer as the monitoring device 20 has been described, but other configurations may be used as long as it is possible to monitor whether or not the arithmetic unit 10 is operating normally. Further, the monitoring device 20 may use either a high level signal or a low level signal as the operating state of the arithmetic unit 10. For example, in FIG. 2, when the arithmetic unit 10 is abnormal, the monitoring device 20 may output a high level signal. In this case, the logic negation circuit in FIG. 2 is not necessary.

10: Arithmetic device 11: Communication wiring 12: Communication wiring 20: Monitoring device 21: Information fixed wiring 30: Transmission control circuit 31: Transmission wiring 32: Communication wiring 33: Communication wiring 40: Communication device 41: Reception wiring 42: Input / output Wiring 100: Electronic control device 200: Control device 300: Bus wiring

Claims (7)

An electronic control device that controls the electrical equipment installed in a vehicle.
A communication device that communicates with other devices via the communication network mounted on the vehicle.
An arithmetic unit that sends and receives data to and from other devices via the communication device,
A monitoring device that monitors whether or not the arithmetic unit is operating normally,
Equipped with
The communication device is configured not to transmit data to the communication network while continuously receiving a signal of a predetermined signal level from the arithmetic unit.
The electronic control device further includes a transmission control circuit that prevents the communication device from transmitting data to the communication network by overwriting a signal output by the arithmetic unit to a signal of the predetermined signal level. ,
When the arithmetic unit is operating normally, the monitoring device controls the transmission control circuit so that the signal output by the arithmetic unit is not overwritten on the signal of the predetermined signal level.
The monitoring device is characterized in that, when the arithmetic unit is not operating normally, the transmission control circuit is controlled so that the signal output by the arithmetic unit is overwritten on the signal of the predetermined signal level. Electronic control device. The computing device uses a communication protocol that occupies the communication network by setting the signal level on the communication network to an occupancy level configured as either a high level or low level logic signal. Data is sent and received to and from the other device via the device.
The communication device is configured not to transmit data to the communication network when the signal on the communication network is set to a signal level other than the occupied level.
When the arithmetic unit is not operating normally, the transmission control circuit overwrites and fixes the signal level output by the arithmetic unit to a signal level other than the occupied level, whereby the communication device is connected to the communication network. The electronic control device according to claim 1, wherein data is not transmitted to the electronic control device. The communication protocol is configured to occupy the communication network by setting the signal level on the communication network to a low level.
The transmission control circuit includes a logical sum circuit that outputs a logical sum of a signal output by the arithmetic unit and a high-level signal indicating that the arithmetic unit is not operating normally to the communication device.
When the arithmetic unit is not operating normally, the monitoring device outputs a signal indicating that the arithmetic unit is not operating normally to the OR circuit, so that the signal output by the arithmetic unit is output. The electronic control device according to claim 2, wherein the transmission control circuit is controlled so that the level is overwritten and fixed to a high level. The communication protocol is configured to occupy the communication network by setting the signal level on the communication network to a low level.
The transmission control circuit includes a switching element for switching whether or not a power supply voltage is connected to the communication device.
When the arithmetic unit is not operating normally, the monitoring device controls the transmission control circuit so as to overwrite and fix the signal level output by the arithmetic unit to a high level by turning on the switching element. 2. The electronic control device according to claim 2. The communication device is configured to shift to a receive-only mode in which data cannot be transmitted when a signal of the predetermined signal level is continuously received from the arithmetic unit for a predetermined time or longer.
In the transmission control circuit, when the arithmetic unit is not operating normally, the signal level output by the arithmetic unit is overwritten and fixed to the predetermined signal level, so that the communication device can be used with respect to the communication network. The electronic control device according to claim 1, wherein data is not transmitted. The communication device is configured to shift to the receive-only mode when it continuously receives a low-level signal from the arithmetic unit for a predetermined time or longer.
The transmission control circuit includes a logical product circuit that outputs a logical product of a signal output by the arithmetic unit and a signal output by the monitoring device to the communication device.
When the arithmetic unit is not operating normally, the monitoring device outputs a low-level signal to the AND circuit, thereby overwriting the signal output by the arithmetic unit into the low-level signal. The electronic control device according to claim 5, wherein the transmission control circuit is controlled as described above. The communication device is configured to shift to the receive-only mode when it continuously receives a low-level signal from the arithmetic unit for a predetermined time or longer.
The transmission control circuit includes a switching element that switches whether or not to connect the ground potential to the communication device.
When the arithmetic unit is not operating normally, the monitoring device controls the transmission control circuit so that the signal output by the arithmetic unit is overwritten as a low-level signal by turning on the switching element. 5. The electronic control device according to claim 5.

Images