JP2008290538A - On-vehicle electronic control unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase transmittable information capacity by superimposing a modulated signal on a message of a CAN protocol. <P>SOLUTION: An on-vehicle electronic control unit 10 which is connected with another electronic control unit through the medium of a CAN communication line 11, consists of a CAN control part 21 for transmitting a CAN message m1 to the CAN communication line 11, a CAN communication part 20 containing a timing generation part 22 for transmitting a timing signal ts at transmission of a data field 44 of the CAN message m1, a storage part 31 for storing data transmitting to the CAN communication line 11, and a modulation signal communicating part 30 having a timing control part 32 for reading data from the storage part 31 when receiving the timing signal ts from the timing generation part 22 and a modulated signal transmitting part having a modulation part 33 for modulating the data into a modulated signal s1. When the timing control part 32 receives the timing signal ts, the modulated signal s1 is superimposed on the CAN message m1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an on-vehicle electronic control unit, and more specifically, increases the amount of information that can be transmitted by superimposing a modulation signal on a CAN message.

Electrical equipment such as engines, transmissions, brakes, air conditioners, and lights mounted on automobiles is controlled by an electronic control unit (ECU), which sends and receives messages to and from other ECUs via multiple communication lines. is doing.
In recent years, with the enhancement of functionality and performance of automobiles, the number of electrical equipment mounted on automobiles and the number of ECUs controlling the electrical equipment has increased, and the number of messages that ECUs transmit and receive via multiple communication lines has also increased rapidly. is doing. For this reason, it is desired to increase the amount of information that can be transmitted.
On the other hand, it is conceivable to increase the amount of information that can be transmitted by increasing the number of multiplexed communication lines. However, since the wiring in the automobile becomes complicated and large-scale, there arises a problem of arrangement space and a problem of increasing the vehicle weight.

Therefore, in Japanese Patent Application Laid-Open No. 2004-336482 (Patent Document 1), when the ECU transmits a baseband signal that is an unmodulated digital signal to a multiplex communication line, the modulated signal obtained by modulating the digital signal is used as the baseband signal. There has been proposed a communication system that performs transmission in a superimposed manner. The modulation signal is modulated so that the frequency band is different from that of the baseband signal, and the ECU that receives the baseband signal on which the modulation signal is superimposed separates the baseband signal and the modulation signal using a bandpass filter, I'm taking it out.
According to this system, since both the baseband signal and the modulation signal are transmitted simultaneously to the same multiplex communication line, it is possible to increase the amount of information that can be transmitted without newly providing a multiplex communication line.

JP 2004-336482 A

However, Patent Document 1 only describes a so-called physical layer for outputting a modulated signal to a multiplex communication line. For example, timing management, address management, error, and retransmission for transmitting a modulated signal are described. There is no description about a communication control system such as control or higher than the so-called data link layer.
Especially when the transmission timing of the modulation signal is not set based on the transmission timing of the baseband signal, it collides with the baseband signal transmitted by another ECU when the ECU transmits the baseband signal to the multiplex communication line. Even when (collision) occurs and the ECU stops transmitting the baseband signal, the ECU may continue to transmit the modulation signal to the multiplex communication line. In this case, the modulation signal transmitted by the ECU is superimposed on the baseband signal transmitted by another ECU, but if the modulation signal is already superimposed on the baseband signal transmitted by another ECU, two modulation signals Is superimposed on the baseband signal, and the ECU receiving the baseband signal cannot separate the two modulation signals.

For this reason, it is necessary to provide communication control functions higher than the data link layer for transmitting the modulation signal in each ECU, and to perform communication control such as stopping transmission of the modulation signal when a baseband signal collision occurs.
However, in order to provide a communication control function for transmitting a modulation signal to the ECU, there is a problem that a processing unit and a storage unit are newly required.

  The present invention has been made in view of the above problems, and it is an object to increase the amount of information that can be transmitted by superimposing the modulation signal on the CAN message without newly providing a communication control function for transmitting the modulation signal. Yes.

In order to solve the above-mentioned problems, the present invention is an on-vehicle electronic control unit connected to another electronic control unit via a CAN communication line,
A CAN communication unit and a modulation signal communication unit;
The CAN communication unit includes a CAN control unit that transmits a CAN message to the CAN communication line;
A timing generation unit connected to the CAN control unit and detecting a transmission time of a data field of the CAN message and transmitting a timing signal;
The modulation signal communication unit is connected to the storage unit storing data, and is connected to the timing generation unit and connected to the timing generation unit to receive data from the storage unit when receiving a timing signal from the timing generation unit A control unit, and a modulation unit that is connected to the timing control unit and modulates the data into a modulation signal having a frequency and / or an amplitude different from that of the data signal stored in the CAN message,
An in-vehicle electronic control unit is provided, wherein a modulation signal transmitted by a modulation signal communication unit is superimposed on a data signal of a CAN message transmitted by the CAN communication unit and transmitted to the CAN communication line.

  The electronic control unit of the present invention transmits a timing signal to the modulation signal communication unit when the CAN communication unit is transmitting the data field of the CAN message to the CAN communication line, and modulates when the modulation signal communication unit receives the timing signal. By transmitting the signal to the CAN communication line, the modulation signal is superimposed on the data signal in the data field of the CAN message. That is, the modulation signal communication unit receives a timing signal from the CAN communication unit using the CAN communication control function of the CAN communication unit, and determines the transmission timing of the modulation signal based on the timing signal.

Therefore, in addition to the data stored in the data field of the CAN message, the electronic control unit can simultaneously transmit the data included in the modulation signal to the same CAN communication line, thereby increasing the amount of information that can be transmitted by the CAN message. Can do.
Further, since the modulation signal communication unit uses the CAN communication control function to determine the modulation signal transmission timing, it is necessary to newly provide a communication control function for determining the modulation signal transmission timing in the modulation signal communication unit. There is no.

  The modulation signal is a signal having a frequency and / or amplitude different from that of the data signal of the CAN message, and is a digital signal.

The superimposition of the modulation signal is not performed in the arbitration field, but is performed in the data field. The reason why the modulation signal is not superimposed in the arbitration field is as follows.
When the electronic control unit transmits a CAN message to the CAN communication line, if a collision occurs with the CAN message of another ECU, the data in the arbitration field of each CAN message between the electronic control unit and the other ECU Arbitration is performed using the signal. When the electronic control unit determines to stop the CAN message transmission in the arbitration, the transmission of the own CAN message is stopped in the middle of the arbitration field transmission.

  When the modulation signal is transmitted while being superimposed on the data signal in the arbitration field, if it is determined to stop transmission by arbitration, the transmission of the modulation signal must be stopped simultaneously with the CAN message. When a collision occurs, the other ECU and the own electronic control unit are simultaneously transmitting a CAN message, and the other ECU also superimposes the modulation signal on the data signal in the arbitration field of the CAN message. In other words, the modulation signals of the own electronic control unit and other ECUs are simultaneously superimposed.

On the other hand, when the modulation signal is superimposed in the data field, even if a collision with a CAN message of another ECU occurs, after the own electronic control unit determines that the transmission of the CAN message is continued by arbitration by the data signal in the arbitration field In addition, since the timing signal is transmitted from the CAN communication unit to the modulation signal communication unit, the transmission of the modulation signal is not stopped by arbitration, and the modulation signal is a data signal of the CAN message simultaneously with the modulation signal of another ECU. Will not be superimposed on. Furthermore, since arbitration is performed by the CAN communication unit, it is not necessary to provide a communication control function for performing arbitration in the modulation signal communication unit.
Note that the modulated signal may be superimposed in the DLC field and CRC field of the CAN message.

The CAN communication unit includes a filter that extracts a CAN message from a superimposed message in which the modulation signal is superimposed on the CAN message received from the other electronic control unit,
Preferably, the modulation signal communication unit includes a filter that extracts a modulation signal from the received superimposed message and a demodulation unit that demodulates the modulation signal extracted by the filter.

  When the ECU of the present invention receives a superimposed message transmitted from another ECU, the superimposed message can be separated into a CAN message and a modulated signal by the filter of the CAN communication unit and the filter of the modulation signal communication unit. The modulated signal can be demodulated into data by the demodulator.

As described above, according to the in-vehicle electronic control unit of the present invention, when the CAN communication unit is transmitting the data field of the CAN message to the CAN communication line, the timing signal is transmitted to the modulation signal communication unit, and the modulation is performed. When the signal communication unit receives the timing signal, it transmits the modulation signal to the CAN communication line so that the modulation signal is superimposed on the data signal of the data field of the CAN message, so that the electronic control unit stores it in the data field of the CAN message. In addition to the transmitted data, the data included in the modulated signal can be transmitted simultaneously, and the amount of information that can be transmitted by the CAN message can be increased.
Further, since the modulation signal communication unit uses the CAN message communication control function of the CAN communication unit, it is not necessary to newly provide a communication control function for controlling the transmission timing of the modulation signal in the modulation signal communication unit. .

Embodiments of the present invention will be described with reference to the drawings.
1 to 5 show a first embodiment of the present invention.
An electronic control unit (ECU) 10 of the present invention is connected to other ECUs 10B and 10C via a CAN communication line 11, and transmits / receives a CAN message m1 to / from another ECU 10.
The ECU 10 of the present invention transmits a message (hereinafter referred to as a superposition message m2) in which a modulation signal s1 obtained by modulating the modulation data d1 is superimposed on the CAN message m1 to the CAN communication line 11.

The ECU 10 includes a CAN communication unit 20 that transmits and receives the CAN message m1, a modulation signal communication unit 30 that transmits and receives the modulation signal s1, a processing unit 40, and an addition unit 41.
The processing unit 40 is connected to the CAN communication unit 20 and the modulation signal communication unit 30, and transmits the CAN message m 1 ID (identifier) and data to the CAN communication unit 20 and sends the modulation data d 1 to the modulation signal communication unit 30. Sending. Further, it receives a CAN message m1 and modulation data d1 transmitted from another ECU 10 via the CAN communication unit 20 and the modulation signal communication unit 30, and controls a sensor (not shown) connected to the ECU 10 and the like. Predetermined processing is performed.

  The CAN communication unit 20 is connected to the addition unit 41 and transmits the CAN message m1 to the addition unit 41. The timing signal ts is transmitted to the modulation signal communication unit 30 when the data signal in the data field 44 of the CAN message m1 is transmitted. Further, the CAN message m 1 is extracted from the superposition message m 2 received from the CAN communication line 11 and transmitted to the processing unit 40.

The modulation signal communication unit 30 is also connected to the addition unit 41, and transmits the modulation signal s 1 to the addition unit 41 while receiving the timing signal ts from the CAN communication unit 20. Also, the modulation signal s1 is extracted from the superposition message m2 on which the modulation signal s1 is superposed, modulated to modulation data d1, and transmitted to the processing unit 40.
The adder 41 is connected to the CAN communication line 11, superimposes the modulation signal s 1 received from the modulation signal communication unit 30 on the data signal of the CAN message m 1 received from the CAN communication unit 20, and sends the superimposed message m 2 to the CAN communication line. 11 is transmitted.

Specifically, the CAN communication unit 20 includes a CAN control unit 21, a timing generation unit 22, a CAN transmission unit 23, a low-pass filter unit 24, and a CAN reception unit 25.
The CAN control unit 21 is connected to the processing unit 40, and the CAN transmission unit 23 and the CAN transmission unit 23 receive and transmit the CAN message m1 in response to an instruction from the processing unit 40.
FIG. 5A shows the format of the CAN message m1 transmitted and received by the CAN communication unit 20. From the upper bits, a 1-bit SOF 41 indicating the start of a message frame and an arbitration field 42 having a message identifier (ID) are provided. In addition, a control field (DLC field 43) indicating information related to control such as message length, a data field 44 indicating message contents to be transmitted and received, and a CRC field 45 for error checking are provided.

The timing generator 22 is connected to the CAN controller 21, receives the CAN message m 1 from the CAN controller 21, and transmits it to the CAN transmitter 23. At this time, when the timing generation unit 22 receives the data signal of the data field 44 of the CAN message m1, the timing signal ts is transmitted to the timing control unit 32 of the modulation signal communication unit 30. The transmission of the timing signal ts to the timing control unit 32 is stopped when the reception of the data signal in the data field 44 is completed.
The CAN transmission unit 23 transmits the CAN message m1 to the addition unit 41.

The low-pass filter unit 24 is connected to the CAN communication line 11, and when the superimposed message m2 on which the modulation signal s1 is superimposed is received from the CAN communication line 11, the modulation signal s1 is removed from the superimposed message m2 and the CAN message m1. Take out.
The CAN receiving unit 25 receives the CAN message m 1 from the low-pass filter unit 24 and transmits it to the CAN control unit 21.

The modulation signal communication unit 30 includes a storage unit 31, a timing control unit 32, a modulation unit 33, a modulation signal transmission unit 34, a high pass filter unit 35 (HPF), a modulation signal reception unit 36, and a demodulation unit 37. I have.
The storage unit 31 stores modulation data d1 to be transmitted to another ECU 10 via the CAN communication line 11, and is connected to the processing unit 40. The modulation data d1 is written from the processing unit 40 to the storage unit 31 at the same time as the CAN message m1 is passed from the processing unit 40 to the CAN control unit 21.

  The timing control unit 32 is connected to the storage unit 31. When the timing signal ts is received from the timing generation unit 22 of the CAN communication unit 20, the timing control unit 32 reads out the modulation data d1 from the storage unit 31 and transmits it to the modulation unit 33.

The modulation unit 33 is connected to the timing control unit 32, and modulates the modulation data d1 received from the timing control unit 32 to obtain a modulation signal s1. In the present embodiment, frequency modulation is performed on the modulation data d1, and the modulation signal s1 is modulated so as to have a frequency sufficiently higher than the transmission frequency of the CAN message m1.
The modulation signal transmission unit 34 is connected to the modulation unit 33, receives the modulation signal s 1 from the modulation unit 33, and outputs it to the addition unit 41.

The high-pass filter unit 35 is connected to the CAN communication line 11. When the superimposed message m2 on which the modulated signal s1 is superimposed is received from the CAN communication line 11, the modulated signal s1 is separated from the superimposed message m2 and extracted. Yes.
The modulation signal receiving unit 36 is connected to the high pass filter unit 35, and transmits the modulation signal s 1 received from the high pass filter unit 35 to the demodulation unit 37.
The demodulator 37 is connected to the storage unit 31, demodulates the modulation signal s 1, returns it to the modulation data d 1, and stores it in the storage unit 31.

The operation when the ECU 10 of the present invention superimposes the modulation signal s1 on the CAN message m1 to obtain the superimposed message m2 will be described with reference to FIGS.
First, operation | movement of the process part 40 is demonstrated using the flowchart of FIG.
In step S1, the processing unit 40 of the ECU 10 issues a command to transmit the CAN message m1 to the CAN communication unit 20. The processing unit 40 transmits the ID of the CAN message m1 and data to be transmitted to the CAN control unit 21 of the CAN communication unit 20.
In step S <b> 2, the processing unit 40 transmits the modulation data d <b> 1 to the storage unit 31 of the modulation signal communication unit 30.

Next, the operation of the CAN communication unit 20 will be described using the flowchart of FIG.
In step S <b> 11, the CAN control unit 21 receives the ID and data of the CAN message m <b> 1 from the processing unit 40.
In step S12, the CAN control unit 21 creates a CAN message m1 from the received ID and data.
In step S <b> 13, the CAN control unit 21 transmits a CAN message m <b> 1 to the timing generation unit 22.

In step S14, the timing generation unit 22 receives the CAN message m1 from the CAN control unit 21, and determines whether or not the data field 44 is received in the CAN message m1. If the data field 44 has been received, the process proceeds to step S15. If not received, step S14 is repeated.
FIG. 5A shows the format of the CAN message m1 transmitted by the CAN control unit 21. The CAN control unit 21 sequentially transmits the CAN message m1 from the upper bits, and the timing generation unit 22 outputs the data signal of the data field 44. Judgment of receiving.

In step S <b> 15, the timing generation unit 22 transmits a timing signal ts to the timing control unit 32. FIG. 5B shows a timing signal ts transmitted by the timing generator 22. The timing generator 22 transmits a timing signal ts when receiving the data field 44.
In step S16, the timing generator 22 determines whether or not the reception of the data field 44 has been completed. When the reception of the data field 44 is completed, the process proceeds to step S17. If not completed, the process returns to step S5.

In step S17, transmission of the timing signal ts is stopped.
In step S <b> 18, the CAN message m <b> 1 is transmitted to the addition unit 41 via the CAN transmission unit 23. Note that step S18 is performed in parallel with the operations of steps S14 to S17, and the timing generator 22 transmits the CAN message m1 to the adder 41 when receiving it. FIG. 5C shows a data field 44 portion of the CAN message m1 transmitted to the adding unit 41. The timing generator 22 receives the CAN message m 1 from the CAN controller 21 and transmits it to the CAN transmitter 23.

Next, the operation of the modulation signal transmission unit 34 will be described with reference to the flowchart of FIG.
In step S <b> 21, the timing control unit 32 determines whether or not the timing signal ts has been received from the timing generation unit 22 of the CAN communication unit 20. If received, the process proceeds to step S22. If not received, step S21 is repeated.
In step S <b> 22, the timing control unit 32 reads the modulation data d <b> 1 from the storage unit 31 and transmits it to the modulation unit 33.
In step S23, the modulation unit 33 frequency-modulates the modulation data d1 received from the timing control unit 32 to obtain a modulation signal s1. FIG. 5D shows a modulation signal s 1 that is an output of the modulation unit 33 of the modulation signal communication unit 30.
In step S <b> 24, the modulation signal s <b> 1 is transmitted to the addition unit 41 via the modulation signal transmission unit 34.

Next, the operation of the adder 41 will be described.
The adder 41 receives the CAN message m1 from the CAN communication unit 20 and receives the modulation signal s1 from the modulation signal communication unit 30.
The adding unit 41 adds the modulation signal s1 to the CAN message m1 to obtain a superimposed message m2. FIG. 5E shows the output of the adder 41, which is a superimposed message m2 in which the modulation signal s1 of FIG. 5D is superimposed on the CAN message m1 of FIG. 5C. The adding unit 41 transmits the superimposed message m2 to the CAN communication line 11.

Next, an operation when the ECU 10 of the present invention receives a superimposed message m2 in which the modulation signal s1 is superimposed on the CAN message m1 from another ECU 10 via the CAN communication line 11 will be described.
First, the operation of the CAN communication unit 20 will be described.
The low-pass filter unit 24 receives the superimposition message m2 and separates the modulation signal s1 from the data field 44 of the superimposition message m2 to obtain a CAN message m1. The CAN receiving unit 25 receives the CAN message m1 from the low-pass filter unit 24, and transmits the CAN message m1 to the processing unit 40 via the CAN control unit 21. The processing unit 40 performs a predetermined process using the CAN message m1.

Next, the operation of the modulation signal communication unit 30 will be described.
The high-pass filter unit 35 receives the superimposed message m2 and separates the modulated signal s1 from the data field 44 of the superimposed message m2 to obtain a modulated signal s1. The modulation signal receiving unit 36 receives the modulation signal s 1 and transmits it to the demodulation unit 37.
The demodulator 37 demodulates the received modulated signal s1 to obtain modulated data d1, and transmits the modulated data d1 to the storage unit 31 for storage. The processing unit 40 reads the modulation data d1 from the storage unit 31.

The processing unit 40 performs predetermined processing using the received modulation data d1 read from the storage unit 31 and the CAN message m1 received via the CAN communication unit 20.
The processing unit 40 can receive the two data of the data stored in the data field 44 of the CAN message m1 and the modulation data d1, and which of the modulation signal communication unit 30 and the CAN communication unit 20 has received the data. By distinguishing, the data is distinguished.

  With this configuration, the electronic control unit can simultaneously transmit the data included in the modulation signal s1 in addition to the data stored in the data field 44 of the CAN message m1, thereby increasing the amount of information that the message can transmit. Can do.

Further, the modulation signal communication unit 30 receives the timing signal ts transmitted at the time of transmission of the data field 44 of the CAN message m1 of the CAN communication unit 20 using the communication control method of the CAN message m1, and receives the timing signal ts. Based on this, the transmission timing of the modulation signal s1 is determined. Further, by not superimposing the modulation signal s1 on the arbitration field 42 of the CAN message m1, when a collision with the CAN message m1 of another ECU 10 occurs, the modulation signal communication unit 30 is not involved in the arbitration, and the CAN communication The unit 20 performs mediation.
Thus, since the CAN communication control function of the CAN communication unit 20 is used for transmission / reception of the modulation signal s1, a new advanced communication method for controlling the transmission / reception of the modulation signal s1 is newly added to the modulation signal communication unit 30. The modulation signal communication unit 30 only needs to receive the timing signal ts from the CAN communication unit 20 and perform modulation or demodulation from the modulation data d1 to the modulation signal s1.

In the present embodiment, the modulation unit 33 of the modulation signal communication unit 30 performs frequency modulation of the modulation data d1, but is not limited to frequency modulation, for example, amplitude modulation, phase modulation, or amplitude shift modulation. Alternatively, phase shift keying, frequency shift keying, orthogonal shift keying, orthogonal frequency division multiplex modulation, or the like may be used.
Further, the adder 41 is deleted from the ECU 10, the CAN transmitter 23 of the CAN communication unit 20 and the modulation signal transmitter 34 of the modulation signal communication unit 30 are directly connected to the CAN communication line 11, and the CAN message m1 and the modulation signal are connected. s1 may be superimposed.
Further, the ECU 10 of the present invention is a gateway (relay connection unit), and may perform relay transmission of the CAN message m1 between the ECUs 10 connected to a plurality of CAN communication lines 11 and connected to different CAN communication lines 11.

It is a block diagram which shows 1st Embodiment of the vehicle-mounted electronic control unit which is this invention. It is a flowchart which shows operation | movement of the process part of an electronic control unit. It is a flowchart which shows operation | movement of the CAN communication part of an electronic control unit. It is a flowchart which shows operation | movement of the modulation signal communication part of an electronic control unit. (A) is a CAN message format, (B) is a timing signal waveform, (C) is a CAN message waveform, (D) is a modulation signal waveform, and (E) is a superimposed message waveform.

Explanation of symbols

10 Electronic control unit (ECU)
11 CAN communication line 20 CAN communication unit 21 CAN control unit 22 Timing generation unit 24 Low pass filter unit 30 Modulation signal communication unit 31 Storage unit 32 Timing control unit 33 Modulation unit 35 High pass filter unit 37 Demodulation unit 40 Processing unit 41 Addition unit 42 Arbitration Field 44 Data field d1 Modulation data m1 CAN message m2 Superposition message s1 Modulation signal ts Timing signal

Claims (2)

An in-vehicle electronic control unit connected to another electronic control unit via a CAN communication line,
A CAN communication unit and a modulation signal communication unit;
The CAN communication unit includes a CAN control unit that transmits a CAN message to the CAN communication line;
A timing generation unit connected to the CAN control unit and detecting a transmission time of a data field of the CAN message and transmitting a timing signal;
The modulation signal communication unit is connected to the storage unit storing data, and is connected to the timing generation unit and connected to the timing generation unit to receive data from the storage unit when receiving a timing signal from the timing generation unit A control unit, and a modulation unit that is connected to the timing control unit and modulates the data into a modulation signal having a frequency and / or an amplitude different from that of the data signal stored in the CAN message,
A vehicle-mounted electronic control unit, wherein a modulation signal transmitted from a modulation signal communication unit is superimposed on a data signal of a CAN message transmitted from the CAN communication unit and transmitted to the CAN communication line. The CAN communication unit includes a filter that extracts a CAN message from a superimposed message in which the modulation signal is superimposed on the CAN message received from the other electronic control unit,
The in-vehicle electronic control unit according to claim 1, wherein the modulation signal communication unit includes a filter that extracts a modulation signal from the received superimposed message, and a demodulation unit that demodulates the modulation signal extracted by the filter.

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