JP2011071638A - Vehicle-mounted communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an on-vehicle communication system which can exclude the influence due to ringing and disturbance noises, etc. by making communication between electronic devices mounted on a vehicle to be an optical communication, and which can also perform arbitration processings which are identical to those of conventional CAN (controller area network) protocol. <P>SOLUTION: The system makes an optical coupler 3, which distributes input light as a center and connects a plurality of optical communication devices 1a, 1b as a star type via optical communication lines 4, 5; respective optical communication devices 1a, 1b input optical signals to a light input unit 31 of the optical coupler 3 by a light transmitting unit 15 and also receive optical signals output from a light output unit 32 of the optical coupler 3 by a light-receiving unit 14, and are constituted to perform collision detection, according to the receiving signal; and the respective optical communication devices 1a, 1b receive the optical signals by the light-receiving unit 14, after transmitting the light signal by the light transmission unit 15, perform the collision detection according to whether the transmission signal and the receiving signal coincide; and if a collision is detected, the device stops transmission processing of the light signal from own device and performs receiving processing. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an in-vehicle communication system that performs communication between a plurality of electronic devices (communication devices) mounted on a vehicle, and more particularly to an in-vehicle communication system that performs optical communication.

  Conventionally, a vehicle is equipped with a large number of electronic devices, and each electronic device is connected via a communication line and emphasizes while exchanging information with each other. Control related to comfort is realized. When an electronic device mounted on a vehicle performs communication, CAN (Controller Area Network) is widely adopted as a communication standard (see Non-Patent Documents 1 and 2).

  In recent years, electronic devices mounted on vehicles tend to increase, and it is necessary to connect many electronic devices through a single communication line (CAN bus) and perform communication between many electronic devices. Yes. However, when many electronic devices are connected to the CAN bus, ringing or the like is likely to occur, and the frequency of occurrence of communication failures increases. Therefore, the number of electronic devices that can be connected to the CAN bus is limited. Also, in places where many electronic devices and communication lines are concentrated, such as in the engine room of a vehicle, disturbance noise is generated in the CAN bus, particularly in the vicinity of electronic devices and communication lines that handle high-voltage signals. There is a problem that communication failure occurs due to superimposition of.

  As a measure for preventing the occurrence of communication failure due to the influence of ringing and disturbance noise as described above, it is conceivable to perform communication between electronic devices by optical communication.

  In the CAN protocol, a plurality of electronic devices are connected to a CAN bus formed by a twisted pair cable that transmits a differential signal, and each electronic device transmits and receives a digital signal represented by the differential signal. CAN is a serial communication protocol, and only one electronic device among a plurality of electronic devices connected to the CAN bus can perform transmission processing, and the other electronic devices can perform transmission processing of one electronic device. Need to wait until it finishes. Further, when a plurality of electronic devices perform transmission processing simultaneously (that is, when a communication collision occurs), communication arbitration processing (arbitration) is performed in each electronic device, and the priority is high. Communication is performed.

  In order to perform arbitration processing for communication collision, each electronic device outputs a transmission signal to the CAN bus and simultaneously detects the signal level of the CAN bus. Each electronic device determines that a communication collision has occurred when the signal level of the detected signal changes with respect to the transmission signal output by itself (when it changes from recessive to dominant), and stops transmission processing. . The dominant signal is dominant over the recessive signal on the CAN bus. Therefore, even if a communication collision occurs, the electronic device that outputs the dominant signal can continue the transmission process.

ISO 11898-1: 2003 Road vehicles--Controller area network (CAN)-Part1: Data link layer and physical signaling ISO 11519-1: 1994 Road vehicles--Low-speed serial data communication--Part1: General and definitions

  In order to prevent communication failures due to ringing, disturbance noise, etc., when communication between electronic devices mounted on a vehicle is made optical communication, in optical communication, transmission and reception are performed on different optical communication lines. The electronic device cannot detect the transmission signal output by itself when the transmission signal is output. Therefore, there is a problem that communication according to the conventional CAN protocol cannot be performed. Therefore, when introducing optical communication, it is necessary for each electronic device to communicate according to a protocol suitable for optical communication different from CAN, and it is necessary to develop an electronic device corresponding to a new protocol. There is a problem of requiring a high development cost.

  The present invention has been made in view of such circumstances, and the object of the present invention is to make communication between electronic devices (communication devices) mounted on a vehicle optically communicated to influence ringing, disturbance noise, and the like. And an in-vehicle communication system capable of performing the same arbitration processing as in the conventional CAN protocol.

  An in-vehicle communication system according to the present invention includes a plurality of light input units and a plurality of light output units, and distributes and outputs light input from one light input unit to a plurality of light output units. And a plurality of optical communication devices connected in a star shape through the optical communication line around the optical distributor, and each optical communication device inputs light to one optical input unit of the optical distributor An optical transmission unit that transmits an optical signal, an optical reception unit that receives an optical signal by receiving light output from one optical output unit of the optical distributor, and the optical reception unit And detecting means for detecting a collision of transmission of an optical signal with another communication device in accordance with the received optical signal.

  In the in-vehicle communication system according to the present invention, the detection unit may detect a collision when the optical signal received by the optical receiver changes with respect to the optical signal transmitted by the optical transmitter. And the optical communication device stops the transmission of the optical signal and receives the optical signal transmitted by another optical communication device when the detection means detects a collision of the transmission of the optical signal. It is characterized by that.

  In the in-vehicle communication system according to the present invention, the optical communication device converts one or a plurality of electric transmission units and electric reception units that transmit and receive electric signals, and the optical signals received by the optical reception unit into electric signals. And a photoelectric conversion unit that converts an electrical signal received by the electrical reception unit into an optical signal, and communicates with one or more electrical communication devices that transmit and receive electrical signals to and from other optical communication devices. It is characterized by mediating.

  The in-vehicle communication system according to the present invention includes the optical transmission unit, the optical reception unit, and the detection unit, one or more electrical transmission units and an electrical reception unit that transmit and receive electrical signals, and the optical reception unit. A photoelectric conversion unit that converts the received optical signal into an electrical signal and converts the electrical signal received by the electrical reception unit into an optical signal, and transmits and receives electrical signals to or from the one or more optical communication devices. It further includes a photoelectric conversion device that mediates communication with one or a plurality of devices.

  In addition, an in-vehicle communication system according to the present invention includes a plurality of optical communication networks including the optical communication device and the photoelectric conversion device connected in a star shape with the optical distributor as a center. The conversion device is connected via a telecommunication line.

  In the in-vehicle communication system according to the present invention, the plurality of optical communication lines connecting the optical input unit of one optical distributor and the optical communication device or the photoelectric conversion device have substantially the same length. Features.

  In the in-vehicle communication system according to the present invention, the optical distributor is configured by using one or a plurality of optical couplers having the two optical input units and the two optical output units. .

In the present invention, an optical distributor having a plurality of light input units and a light output unit and distributing and outputting light input from one light input unit to the plurality of light output units is used. An in-vehicle communication system is configured by connecting a plurality of optical communication devices in a star shape to each device via optical communication lines. In this optical distributor, when optical signals are input from a plurality of input units, the plurality of optical signals are combined and output from all the optical output units.
Each optical communication device is connected to one optical input unit and one optical output unit of the optical distributor via an optical communication line. The optical communication device can transmit an optical signal to one optical input unit of the optical distributor and receive an optical signal distributed and output by the optical distributor. By comparing with the optical signal, a transmission collision of the optical signal can be detected.
As a result, the optical communication apparatus can perform communication arbitration similar to the CAN protocol by making the presence / absence of light correspond to dominant / recessive of the CAN protocol, and perform communication processing according to the CAN protocol. Is possible. Therefore, it is possible to configure the optical communication device of the present invention simply by installing an interface circuit for connecting to an optical communication line, etc. with respect to the conventional communication device, and developing the optical communication device at low cost. can do.

  In the present invention, the optical communication device transmits an optical signal with another optical communication device when a change occurs in the optical signal received via the optical distributor with respect to the optical signal transmitted by itself. Detect collisions. When a collision is detected, the optical communication device stops the transmission of the optical signal and receives the optical signal transmitted by another optical communication device. The processes such as collision detection and transmission stop are obtained by applying substantially the same method as the CAN protocol arbitration to optical communication. Therefore, the optical communication apparatus according to the present invention can be realized by modifying or adding a relatively small number of circuits to a communication apparatus that performs communication according to the conventional CAN protocol.

Moreover, in this invention, the function which transmits / receives an electrical signal with the function which transmits / receives an optical signal is mounted in the 1 or several optical communication apparatus contained in a vehicle-mounted communication system. By making this optical communication device perform mutual conversion between electric signals to be transmitted and received and optical signals, and mediating communication between other optical communication devices and the telecommunication device, the in-vehicle communication system can perform telecommunication and optical communication. It can be mixed.
Alternatively, the in-vehicle communication system includes a photoelectric conversion device that has an optical communication function and an electric communication function and performs mutual conversion between an electrical signal and an optical signal, and the photoelectric conversion device is one or more optical communication devices and one or more optical communication devices. It is set as the structure which mediates communication between these telecommunications apparatuses. Similarly, it is possible to mix electrical communication and optical communication in the in-vehicle communication system.
Since the communication line of the in-vehicle communication system is arranged in a limited space in the vehicle, there is a possibility that the communication line needs to be bent. However, when an optical fiber is used as the optical communication line, There is a problem that it is difficult to bend and arrange the fiber, that is, the optical fiber has a low degree of freedom of arrangement. Therefore, by allowing the electric communication line that is resistant to bending to be mixed, the degree of freedom of arrangement of the in-vehicle communication system in the vehicle can be increased.

In the present invention, a single optical communication network is configured by connecting an optical communication device and a photoelectric conversion device in a star shape with the optical distributor as the center, and photoelectric conversion of a plurality of optical communication networks is performed via an electric communication line. An in-vehicle communication system is configured by connecting devices. As a result, an in-vehicle communication system that performs optical communication within a star-type optical communication network and performs electrical communication between the optical communication networks is realized.
For example, optical communication is performed at locations where many devices are concentrated, such as in the engine room at the front of the vehicle, and there is a possibility that the communication line may be bent at a relatively long distance such as between the front of the vehicle and the rear of the vehicle. It is possible to realize a configuration suitable for the advantages and disadvantages of optical communication and telecommunications, such as performing electrical signals at high locations. In particular, in a vehicle, since a large number of devices are often arranged at several specific locations, the configuration of the present invention is suitable.

  In the present invention, the lengths of the optical communication lines that connect the optical input unit of the optical distributor, the optical communication device, and the photoelectric conversion device are substantially the same for one optical distributor included in the in-vehicle communication system. . This makes it difficult for the timing of the optical signal input from the optical communication device and the photoelectric conversion device to the optical distributor to be shifted, so that processing such as communication collision detection and arbitration can be reliably performed.

  In the present invention, the cost of the in-vehicle communication system can be reduced by configuring an optical distributor using one or a plurality of inexpensive two-input two-output optical couplers. For example, when optical communication is performed between two optical communication devices, one optical coupler may be used, and when optical communication is performed between four optical communication devices, four optical couplers may be used. When optical communication is performed between optical communication devices, 12 optical couplers may be used.

  In the case of the present invention, a plurality of optical communication devices are connected in a star shape centering on the optical distributor, and each optical communication device transmits an optical signal to one optical input unit of the optical distributor, and the optical distributor By receiving the optical signal output by the system and detecting the collision based on the received optical signal, the communication of the in-vehicle communication system is converted to optical communication to eliminate the influence of ringing, disturbance noise, etc. In addition, since communication processing similar to that of the conventional CAN protocol can be performed, the in-vehicle communication system can be optically communicated at low cost.

It is a block diagram which shows the structure of the vehicle-mounted communication system which concerns on Embodiment 1 of this invention. It is a flowchart which shows the procedure of the transmission process which the optical communication apparatus of the vehicle-mounted communication system which concerns on this invention performs. It is a block diagram which shows the structure of the vehicle-mounted communication system which concerns on Embodiment 2 of this invention. It is a block diagram which shows the structure of the vehicle-mounted communication system which concerns on Embodiment 2 of this invention. It is a schematic diagram which shows the structural example of the optical splitter used for a vehicle-mounted communication system. It is a schematic diagram which shows the structural example of the optical splitter used for a vehicle-mounted communication system. It is a block diagram which shows the structure of the vehicle-mounted communication system which concerns on Embodiment 3 of this invention. It is a schematic diagram which shows the example which mounts the vehicle-mounted communication system which concerns on Embodiment 3 in the vehicle.

(Embodiment 1)
Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof. 1 is a block diagram showing a configuration of an in-vehicle communication system according to Embodiment 1 of the present invention. The in-vehicle communication system according to Embodiment 1 has a configuration in which a plurality (two) of optical communication devices 1a and 1b are connected to an optical coupler 3 via optical communication lines 4 and 5, respectively. It is a star type network system.

  Optical communication devices 1a and 1b of an in-vehicle communication system are those in which an optical communication function is mounted on an electronic device such as an ECU (Electronic Control Unit) mounted on a vehicle (not shown). In FIG. 1, only one optical communication device 1a is shown in a detailed configuration, and the other optical communication device 1b has the same configuration, and therefore the detailed configuration is not shown. Each of the optical communication devices 1a and 1b includes a CPU (Central Processing Unit) 11, a CAN control unit 12, and an optical communication unit 13.

  The CPU 11 of the optical communication devices 1a and 1b executes processing such as various calculations necessary for operation control and control of each unit in the device by executing a program stored in advance in a ROM (Read Only Memory) or the like. It is. In addition, when it is necessary to exchange information with other optical communication apparatuses 1a and 1b in these processing steps, the CPU 11 gives a communication instruction to the CAN control unit 12 to thereby transmit the other optical communication apparatuses 1a and 1b. Can communicate with. When the CPU 11 transmits data to the other optical communication apparatuses 1 a and 1 b, the CPU 11 gives this data to the CAN control unit 12. Further, when receiving data from the other optical communication devices 1a and 1b, the CAN control unit 12 gives this data to the CPU 11.

  When receiving data to be transmitted from the CPU 11, the CAN control unit 12 converts this data into data for transmission according to the data format of the CAN protocol, and provides the data to the optical transmission unit 15 of the optical communication unit 13. Data transmitted and received by the CAN protocol is composed of a plurality of fields such as an arbitration field, a control field, a data field, a CRC (Cyclic Redundancy Check) field, and an ACK (ACKnowledgement) field, and the data given from the CPU 11 is Stored in the data field. The arbitration field is data for arbitrating communication collisions. A value corresponding to the priority of transmission data is stored, and data “0 (dominant)” has a higher priority than data “1 (recessive)”. high.

  The CAN control unit 12 is given data received by the optical receiving unit 14 of the optical communication unit 13. Since this received data is in the CAN protocol data format, the CAN control unit 12 extracts necessary data from the data field of the received data and gives it to the CPU 11. Thereby, CPU11 can perform the process according to the received data from other optical communication apparatuses 1a and 1b.

  The optical communication unit 13 includes an optical reception unit 14 and an optical transmission unit 15, and an electrical signal transmitted / received to / from the CAN control unit 12 and light transmitted / received to / from other optical communication devices 1 a and 1 b. It performs mutual conversion with signals. The optical transmission unit 15 of the optical communication unit 13 includes a light source such as a light emitting diode and a drive circuit for turning on / off the light source, and transmits transmission data given as an electrical signal from the CAN control unit 12. The optical signal is converted into an optical signal, and this optical signal is output to the optical communication line 4 for transmission.

  The optical receiver 14 of the optical communication unit 13 includes a light receiving element such as a photodiode, for example, and detects light emitted from the optical communication line 5 for reception. The optical receiver 14 can output an electrical signal corresponding to the light detected by the light receiving element, thereby receiving the optical signal transmitted by the other optical communication devices 1a and 1b and converting it into an electrical signal, This can be given to the CAN control unit 12.

  The optical coupler 3 of the in-vehicle communication system has a configuration in which two optical input units 31 are provided on one side and two optical output units 32 are provided on the other side, and light input from the optical input unit 31 is provided. Is a light distributor that distributes the light to two light output units 32. The first optical input unit 31 of the optical coupler 3 is connected to the optical transmission unit 15 of the optical communication device 1a via the optical communication line 4, and the second optical input unit 31 is connected to the optical transmission unit 15 of the optical communication device 1b. They are connected via an optical communication line 4. The first optical output unit 32 of the optical coupler 3 is connected to the optical receiver 14 of the optical communication device 1a via the optical communication line 5, and the second optical output unit 32 is the optical receiver 14 of the optical communication device 1b. Are connected to each other via an optical communication line 5.

  As a result, the optical signal transmitted from the optical transmission unit 15 of the optical communication device 1a via the optical communication line 4 is input to the input unit 31 of the optical coupler 3, and is distributed by the optical coupler 3 to be transmitted to the two optical output units. 32 and received by both of the optical communication devices 1a and 1b. Similarly, the optical signal transmitted by the optical communication device 1b is distributed by the optical coupler 3 and received by both the optical communication devices 1a and 1b. When the optical communication devices 1a and 1b both transmit optical signals, the two optical signals are combined and distributed by the optical coupler 3, and the combined optical signals are output from the two optical output units 32, respectively. And received by both of the optical communication apparatuses 1a and 1b.

  The optical signals transmitted by the optical communication apparatuses 1a and 1b are obtained by associating digital data with / without light. Since the optical coupler 3 outputs light to both of the two optical output units 32 when light is input to one of the two optical input units 31, the presence or absence of light in the optical signal is determined. By making correspondence with dominant / recessive in the data format of the CAN protocol, arbitration similar to that of the CAN protocol can be performed.

  The optical communication line 4 connecting the optical transmission unit 15 of the optical communication device 1a and the optical input unit 31 of the optical coupler 3 is connected to the optical transmission unit 15 of the optical communication device 1b and the optical input unit 31 of the optical coupler 3. It is preferable that the optical communication line 4 has substantially the same length. This is to suppress the occurrence of a difference in the timing at which the optical signal transmitted from the optical communication device 1 a and the optical signal transmitted from the optical communication device 1 b are input to the optical coupler 3. However, there may be some difference in the lengths of the two optical communication lines 4 depending on the communication speed of the optical communication.

  When the optical communication devices 1a and 1b of the in-vehicle communication system transmit data to the other optical communication devices 1a and 1b, the optical data of the optical communication unit 13 is converted from the transmission data converted into a predetermined data format by the CAN control unit 12. The transmitter 15 converts the optical signal and transmits it. The optical communication devices 1a and 1b convert the optical signal received by the optical receiving unit 14 of the optical communication unit 13 after the transmission of the optical signal into the received data of the electric signal, and the data transmitted by the received data. Is determined by the CAN control unit 12 to detect occurrence of a collision of optical signal transmission with the other optical communication apparatuses 1a and 1b.

  When the transmission data and the reception data match and there is no collision in transmission, the optical communication devices 1a and 1b can continue the transmission process. When the transmission data and the reception data do not match and there is a collision in transmission, the optical communication apparatuses 1a and 1b that have detected the collision stop the transmission process, and the data transmitted by the other optical communication apparatuses 1a and 1b Receive processing. Even if optical signal collision actually occurs, the optical communication devices 1a and 1b that transmit high priority data do not detect the collision and may continue the transmission process. it can.

  FIG. 2 is a flowchart showing a procedure of transmission processing performed by the optical communication devices 1a and 1b of the in-vehicle communication system according to the present invention. When performing data transmission to the other optical communication devices 1a and 1b, the CPU 11 of the optical communication devices 1a and 1b first gives the data to be transmitted to the CAN control unit 12, and the CAN control unit 12 converts the data format. The optical transmission unit 15 converts the transmission data into an optical signal and outputs it, thereby transmitting the optical signal (step S1). After the transmission of the optical signal, the optical communication devices 1a and 1b receive the optical signal at the optical receiving unit 14 (step S2), convert the received optical signal into received data of the electrical signal, and send it to the CAN control unit 12. give.

  Subsequently, the optical communication devices 1a and 1b determine in the CAN control unit 12 whether or not the optical signal (transmission signal) transmitted in step S1 matches the optical signal (reception signal) received in step S2. (Step S3). When the transmission signal and the reception signal do not match (S3: NO), a collision of transmission of the optical signal with the other optical communication devices 1a and 1b is detected, and the optical communication devices 1a and 1b stop the transmission process, The CAN control unit 12 performs reception processing of optical signals transmitted from the other optical communication devices 1a and 1b (step S4), and determines whether the reception processing is completed (step S5). If the reception process has not ended (S5: NO), the optical communication devices 1a and 1b return the process to step S4 and continue the reception process. When the reception process is completed (S5: YES), the optical communication devices 1a and 1b return the process to step S1 and perform the transmission process again.

  When the transmission signal and the reception signal match (S3: YES), the optical communication apparatuses 1a and 1b can continue the transmission process because the collision of the optical signals is not detected. Therefore, the optical communication devices 1a and 1b determine whether or not the transmission of the optical signal related to the transmission data is finished (step S6). If the transmission is not finished (S6: NO), the process proceeds to step S1. To continue the transmission process. When the transmission of the optical signal related to the transmission data is finished (S6: YES), the optical communication devices 1a and 1b finish the transmission process.

  In the in-vehicle communication system according to the first embodiment having the above configuration, a plurality of optical communication devices 1a and 1b are arranged in a star shape through the optical communication lines 4 and 5 with the optical coupler 3 that distributes the input light as a center. The optical communication devices 1a and 1b input the optical signal to the optical input unit 31 of the optical coupler 3 at the optical transmission unit 15 and the optical signal output from the optical output unit 32 of the optical coupler 3 to the optical signal. By adopting a configuration in which the receiving unit 14 receives the collision and detects the collision according to the received signal, it is possible to realize optical communication that is not affected by ringing, disturbance noise, and the like. Further, since optical communication can be performed in the same manner as the CAN protocol in telecommunications, the CAN control unit 12 provided in each optical communication device 1a, 1b is the same as that provided in the communication device that performs telecommunications. However, since the optical communication devices 1a and 1b can be realized by providing the optical communication unit 13 in a conventional communication device that performs telecommunications, the optical communication devices 1a and 1b can be developed at low cost.

  Each optical communication device 1a, 1b receives an optical signal at the optical receiver 14 after transmitting an optical signal at the optical transmitter 15, and depends on whether the transmitted signal and the received signal match. When collision is detected and the collision is detected, optical communication arbitration can be performed by the same method as the CAN protocol by stopping the transmission process of its own optical signal and performing the reception process. Further, the optical communication line 4 connecting the optical transmission unit 15 of the optical communication device 1a and the optical input unit 31 of the optical coupler 3 and the optical transmission unit 15 of the optical communication device 1b and the optical input unit 31 of the optical coupler 3 are connected. By making the optical communication line 4 substantially the same length, there is a difference in the timing at which the optical signal transmitted from the optical communication device 1a and the optical signal transmitted from the optical communication device 1b are input to the optical coupler 3. Occurrence can be suppressed, and processing such as collision detection and arbitration in optical communication can be reliably performed.

  In the present embodiment, the in-vehicle communication system is configured to perform optical communication between the two optical communication devices 1a and 1b using the two-input two-output optical coupler 3. However, the present invention is not limited to this. A configuration in which three or more optical communication devices perform optical communication using an optical coupler having many inputs and outputs may be employed. Even if three or more optical communication devices are configured to perform optical communication, each optical communication device is connected to a star type centered on an optical coupler via an optical communication line, and the above-described optical communication collision detection and arbitration is performed. Such processing may be performed by each optical communication device.

(Embodiment 2)
3 and 4 are block diagrams showing the configuration of the in-vehicle communication system according to Embodiment 2 of the present invention. FIG. 3 shows the overall configuration of the in-vehicle communication system, and FIG. The detailed configuration of the apparatus is shown. The in-vehicle communication system according to the first embodiment described above is configured such that the two optical communication devices 1a and 1b perform only optical communication. In contrast, the in-vehicle communication system according to the second embodiment is a system in which optical communication and telecommunication are mixed. The in-vehicle communication system according to the second embodiment includes two optical communication devices 7a and 7b and one optical coupler 3 as in the first embodiment, and includes four telecommunication devices 9a to 9d. However, the optical communication devices 7a and 7b of the in-vehicle communication system according to the second embodiment include an optical communication function that performs optical communication via the optical communication lines 4 and 5 and electrical communication that performs electrical communication via the CAN bus 6. It is the structure which has a function.

  In the optical communication device 7a of the in-vehicle communication system according to the second embodiment, the optical transmission unit 15 is connected to the first optical input unit 31 of the optical coupler 3 via the optical communication line 4, and the optical reception unit 14 is optical communication. The first optical output unit 31 of the optical coupler 3 is connected via the line 5. Similarly, in the optical communication device 7b, the optical transmission unit 15 is connected to the second optical input unit 31 of the optical coupler 3 via the optical communication line 4, and the optical reception unit 14 is connected to the optical coupler via the optical communication line 5. 3 to the second light output unit 31. That is, the two optical communication devices 7 a and 7 b are connected in a star shape with the optical coupler 3 as the center through the optical communication lines 4 and 5.

  The optical communication devices 7a and 7b have the CPU 11, the CAN control unit 12 and the optical communication unit 13 similar to the optical communication devices 1a and 1b of the first embodiment, and the CAN control unit 71 and the electric communication unit 72. In addition. The CAN control unit 71 performs the same processing as the CAN control unit 12, converts the data given from the CPU 11 into transmission data according to the data format of the CAN protocol, and gives the data to the telecommunication unit 72. While transmitting, necessary data is extracted from the received data received by the telecommunication unit 72 and given to the CPU 11. Therefore, the CPU 11 can use the CAN control unit 12 when performing optical communication, and can use the CAN control unit 71 when performing electrical communication. The CAN control unit 71 performs processing such as communication collision detection and mediation using the CAN protocol.

  The telecommunication units 72 of the optical communication devices 7a and 7b are connected to the CAN bus 6, and output the transmission data given from the CAN control unit 71 to the CAN bus 6 as electric signals, so that the telecommunication devices 9a to 9a- The electric signal is transmitted to 9d. Further, the telecommunication unit 72 receives an electric signal by detecting the potential of the CAN bus 6, and gives the received data obtained thereby to the CAN control unit 71. The CAN control unit 71 can detect a communication collision depending on whether the transmitted data matches the received data.

  In the in-vehicle communication system according to the second embodiment, the optical communication device 7a and the telecommunication devices 9a and 9b are connected to a common CAN bus 6 and can perform electrical communication according to the CAN protocol. The device 7b and the telecommunication devices 9c and 9d are connected to a common CAN bus 6 and can perform telecommunication in accordance with the CAN protocol.

  The telecommunication devices 9a to 9d include a CPU 91, a CAN control unit 92, a telecommunication unit 93, and the like. The CPU 91, the CAN control unit 92, and the telecommunication unit 93 included in the telecommunication devices 9a to 9d have substantially the same configuration as the CPU 11, the CAN control unit 71, and the telecommunication unit 72 included in the optical communication devices 7a, 7b. Therefore, the telecommunication devices 9a to 9d can transmit and receive electrical signals via the CAN bus 6, and can perform processing such as communication collision detection and arbitration by the CAN protocol.

  In the in-vehicle communication system according to the second embodiment having the above configuration, the optical communication devices 7a and 7b are configured to have not only the optical communication function but also the telecommunication function, so that the in-vehicle communication system has optical communication and telecommunication. And the versatility of the in-vehicle communication system can be improved. In addition, since the optical communication devices 7a and 7b can perform both optical communication and electrical communication by a communication method based on the CAN protocol, an increase in development cost of the optical communication devices 7a and 7b can be suppressed. Further, for example, telecommunication devices 9a and 9b connected to one CAN bus 6 are connected to telecommunication devices 9c and 9d connected to the other CAN bus 6 via optical communication devices 7a and 7b and an optical coupler 3, respectively. It can also be set as the structure which communicates, By this, the versatility of a vehicle-mounted communication system can be improved more.

  In the present embodiment, the two telecommunication devices 9a to 9d are connected to the optical communication devices 7a and 7b via the CAN bus 6. However, the present invention is not limited to this. The number of telecommunication devices 9a to 9d to be connected to is arbitrary.

  In addition, since the other structure of the vehicle-mounted communication system which concerns on Embodiment 2 is the same as that of the structure of the vehicle-mounted communication system which concerns on Embodiment 1, the same code | symbol is attached | subjected to the same location and detailed description is abbreviate | omitted To do.

(Embodiment 3)
The in-vehicle communication system according to the above-described first and second embodiments has a configuration in which two optical communication devices 1a, 1b or 7a, 7b perform optical communication using one two-input two-output optical coupler 3. In contrast, the in-vehicle communication system according to Embodiment 3 enables more optical communication devices to perform optical communication.

  5 and 6 are schematic diagrams illustrating an example of the configuration of an optical distributor used in an in-vehicle communication system. FIG. 5A shows the 2-input 2-output optical coupler 3 used in the in-vehicle communication system according to the first and second embodiments (however, in this figure, the optical input unit 31 and the optical output unit). 32 is omitted, and optical signal input / output is indicated by arrows). By using one optical coupler 3, as shown in the first and second embodiments, two optical communication devices can perform optical communication.

  FIG. 5B shows an example in which a four-input four-output optical distributor is configured by using four optical couplers 3a to 3d. In this optical distributor, two two-input two-output optical couplers 3a and 3b are provided at the front stage (input side), and four optical signals output from the four optical communication devices are supplied to the optical input unit 31 of the optical couplers 3a and 3b. Each can be entered. Further, the two optical couplers 3c and 3d are set as the subsequent stage (output side), and the two optical output units 32 of the preceding optical coupler 3a are connected to the optical input units 31 of the two subsequent optical couplers 3c and 3d, respectively. The two optical output units 32 of the optical coupler 3b are connected to the optical input units 31 of the two subsequent optical couplers 3c and 3d. As a result, the optical signal input to one of the optical input units 31 of the upstream optical couplers 3a and 3b is output from all the optical output units 32 of the downstream optical couplers 3c and 3d. When a plurality of optical signals are input to the preceding optical couplers 3a and 3b, these optical signals are combined and output from all the optical output units 32 of the subsequent optical couplers 3c and 3d.

  FIG. 6C shows an example in which an optical splitter 30 with 8 inputs and 8 outputs is configured using 12 optical couplers 3a to 3l. The optical distributor 30 includes four optical couplers 3a to 3d arranged in the front stage, four optical couplers 3e to 3h arranged in the middle stage, and four optical couplers 3i to 3l arranged in the rear stage. The optical signals output from the two preceding optical couplers 3a and 3b are respectively input to the two middle optical couplers 3e and 3f, and the optical signals output from the two preceding optical couplers 3c and 3d are Are respectively input to the two optical couplers 3g and 3h in the middle stage. In other words, the optical couplers 3a, 3b, 3e, and 3f form a 4-input 4-output optical distributor similar to FIG. 5B, and the optical couplers 3c, 3d, 3g, and 3h configure FIG. 4) and 4 output optical distributors are configured.

  The optical signals output from the two middle optical couplers 3e and 3g of the optical distributor 30 are respectively input to the subsequent two optical couplers 3i and 3j and output from the two middle optical couplers 3f and 3h. The optical signals are input to the two subsequent optical couplers 3k and 3l. As a result, the optical signals input to any one of the optical input units 31 of the preceding four optical couplers 3a to 3d are output from all the optical output units 32 of the subsequent four optical couplers 3i to 3l. When a plurality of optical signals are input to the preceding optical couplers 3a to 3d, these optical signals are combined and output from all the optical output units 32 of the subsequent optical couplers 3i to 3l.

  FIG. 7 is a block diagram showing the configuration of the in-vehicle communication system according to Embodiment 3 of the present invention. The in-vehicle communication system according to Embodiment 3 includes three 8-input 8-output optical distributors 30 shown in FIG. In each optical distributor 30, seven optical communication devices 1 and one photoelectric conversion device 7 are connected in a star shape via optical communication lines 4 and 5 to form star networks 8a to 8c, respectively. is doing. In FIG. 7, the 8-input 8-output optical splitter 30 is indicated by an octagonal symbol, the optical communication device 1 is indicated by a circular symbol, and the photoelectric conversion device 7 is indicated by a square symbol. Although the optical communication devices 1 are not shown in the star networks 8b and 8c, seven optical communication devices 1 are connected to the optical distributor 30, respectively.

  The optical communication device 1 has the same configuration as that of the optical communication devices 1a and 1b described in the first embodiment, and the optical transmission unit 15 is one of the optical input units 31 of the optical couplers 3a to 3d constituting the optical distributor 30. And the optical receiver 14 is connected to one of the optical output units 32 of the optical couplers 3 i to 3 l constituting the optical distributor 30 via the optical communication line 5. Yes. As a result, the optical communication device 1 communicates with another optical communication device 1 and the photoelectric conversion device 7 in the same star network 8a to 8c (that is, connected to the same optical distributor 30) by the CAN protocol. It can be performed.

  The photoelectric conversion device 7 has the same configuration as the optical communication devices 7a and 7b described in the second embodiment, and has an optical communication function and an electric communication function. In the photoelectric conversion device 7, the optical transmitter 15 is connected to one of the optical input units 31 of the optical distributor 30 via the optical communication line 4, and the optical receiver 14 is connected to any of the optical output units 32 of the optical distributor 30. In addition to being connected via the optical communication line 5, it is connected to the photoelectric conversion devices 7 of the other star type networks 8 a to 8 c via the CAN bus 6. As a result, the photoelectric conversion device 7 can perform optical communication with the optical communication device 1 in the same star network 8a to 8c, and can communicate with other photoelectric conversion devices 7 via the CAN bus 6. Communication can be performed.

  Further, when receiving an optical signal from the optical communication device 1 in the same star network 8a to 8c by optical communication, the photoelectric conversion device 7 converts the received optical signal into an electric signal by the optical communication unit 13, and converts the optical signal. By outputting the electrical signal from the electrical communication unit 72 to the CAN bus 6, the electrical signal can be transmitted to the photoelectric conversion devices 7 of the other star networks 8 a to 8 c. When the photoelectric conversion device 7 receives an electrical signal from another photoelectric conversion device 7, the photoelectric conversion device 7 converts the received electrical signal into an optical signal by the optical communication unit 13 and outputs the optical signal to the optical communication line 4. Can be transmitted to the optical communication device 1 in the type networks 8a to 8c. That is, the photoelectric conversion device 7 mediates electrical communication and optical communication.

  Accordingly, for example, an optical signal transmitted from one optical communication device 1 of the star network 8a is received by the other optical communication device 1 and the photoelectric conversion device 7 in the same star network 8a, and the photoelectric conversion device. 7 is converted into an electrical signal and transmitted to the photoelectric conversion devices 7 of the other star type networks 8b and 8c. The photoelectric conversion devices 7 of the other star type networks 8b and 8c that have received this electrical signal convert it into an optical signal. It is converted and transmitted to the optical communication apparatus 1 in the star type networks 8b and 8c. That is, each optical communication device 1 can transmit / receive data to / from all other optical communication devices 1 included in the in-vehicle communication system.

  FIG. 8 is a schematic diagram illustrating an example in which the in-vehicle communication system according to the third embodiment is mounted on the vehicle 100. In the illustrated example, a star network 8 a is disposed at the front of the vehicle 100, a star network 8 b is disposed at the center of the vehicle 100, and a star network 8 c is disposed at the rear of the vehicle 100. The three star networks 8a to 8c are connected to the photoelectric conversion device 7 via the CAN bus 6 disposed along the vehicle body of the vehicle 100, and can transmit and receive electrical signals to and from each other. it can.

  For example, in the engine room in the front part of the vehicle 100, since it is necessary to install a large number of electronic devices in a narrow space, an optical communication function is provided in these electronic devices to form the optical communication device 1, and light distribution is performed. A star network 8a can be configured by connecting a plurality of optical communication devices 1 through optical communication lines 4 and 5 around the device 30. Thereby, the optical communication between the optical communication apparatuses 1 performed in the star network 8a can be performed with high accuracy without being affected by ringing, disturbance noise, and the like. The same applies to the optical communication in the star-type networks 8b and 8c arranged at the center and the rear of the vehicle 100.

  In addition, since communication between electronic devices arranged in relatively distant places in the vehicle 100 is likely to be arranged by bending a communication line connecting the electronic devices, an electric communication line is used. Preferably it is done. Therefore, the star-type networks 8a to 8c disposed in the front, the center, and the rear of the vehicle 100 are connected using the CAN bus 6, and electrical communication is performed by the photoelectric conversion device 7, whereby the vehicle 100 The communication line can be easily arranged.

  As described above, the in-vehicle communication system according to the third embodiment configures the star networks 8a to 8c that perform optical communication with the optical distributor 30 as the center at locations where the distance between the electronic devices in the vehicle 100 is short. In addition, it is preferable to adopt a configuration in which electrical communication via the CAN bus 6 is performed at locations where the distance between electronic devices is long.

  In the in-vehicle communication system according to the third embodiment having the above configuration, the star communication networks 1a to 8c are configured by connecting the optical communication device 1 and the photoelectric conversion device 7 around the optical distributor 30, and each star network is connected. By adopting a configuration in which the photoelectric conversion devices 7 of 8a to 8c are connected by the CAN bus 6, an in-vehicle communication system in which optical communication and telecommunications are mixed can be realized, so that the versatility of the in-vehicle communication system can be improved. . Further, since it is possible to adopt a configuration in which optical communication is performed at a place where the distance between the devices is short and dense, and electric communication is performed at a place where the distance between the devices is long, it is easy to arrange communication lines in the vehicle 100. In addition to the improvement, it is possible to suppress the influence of ringing, disturbance noise, and the like at locations where the apparatus is dense. Further, by configuring the 8-input 8-output optical distributor 30 using a plurality of 2-input 2-output optical couplers 3a to 3l, the optical distributor 30 having more inputs and outputs can be realized at low cost, and in-vehicle communication. Increase in system cost can be suppressed.

  In the present embodiment, the in-vehicle communication system is configured to include the three star networks 8a to 8c. However, the configuration is not limited to this, and the configuration includes two or less or four or more star networks. There may be. Moreover, although each star type network 8a-8c was set as the structure provided with the seven optical communication apparatuses 1, respectively, it is not restricted to this, The structure provided with six or less optical communication apparatuses 1 may be sufficient, and many more A configuration including eight or more optical communication apparatuses 1 using an optical distributor having the following inputs and outputs may be used.

  In addition, since the other structure of the vehicle-mounted communication system which concerns on Embodiment 3 is the same as that of the structure of the vehicle-mounted communication system which concerns on Embodiment 1, 2, the same code | symbol is attached | subjected to a same location and detailed description Is omitted.

1, 1a, 1b Optical communication device 3, 3a-3l Optical coupler (optical distributor)
4, 5 Optical communication line 6 CAN bus (electric communication line)
7 Photoelectric conversion device 7a, 7b Optical communication device (photoelectric conversion device)
8a-8c Star type network (optical communication network)
9a-9d Telecommunications device 11 CPU
12 CAN control unit (detection means)
13 Optical communication unit (photoelectric conversion unit)
14 optical receiver 15 optical transmitter 30 optical distributor 31 optical input unit 32 optical output unit 71 CAN control unit 72 electrical communication unit (electrical transmission unit, electrical reception unit)
91 CPU
92 CAN control unit 93 Telecommunications unit 100 vehicle

Claims (7)

A light distributor having a plurality of light input units and a plurality of light output units, and distributing and outputting the light input from one light input unit to the plurality of light output units;
A plurality of optical communication devices connected in a star shape through an optical communication line around the optical distributor;
Each optical communication device
An optical transmission unit that transmits an optical signal by inputting light to one optical input unit of the optical distributor;
An optical receiver that receives an optical signal by receiving light output from one optical output unit of the optical distributor;
An in-vehicle communication system comprising: a detecting unit that detects a collision of transmission of an optical signal with another communication device according to an optical signal received by the optical receiving unit. The detection means is configured to detect a collision when the optical signal received by the optical receiver changes with respect to the optical signal transmitted by the optical transmitter,
The optical communication device is configured to stop transmission of an optical signal and receive an optical signal transmitted from another optical communication device when the detection unit detects a collision in transmission of the optical signal. The in-vehicle communication system according to claim 1, wherein The optical communication device is:
One or more electrical transmitters and electrical receivers for transmitting and receiving electrical signals;
A photoelectric conversion unit that converts an optical signal received by the optical reception unit into an electrical signal and converts the electrical signal received by the electrical reception unit into an optical signal;
The in-vehicle communication system according to claim 1 or 2, wherein communication between one or a plurality of telecommunication devices that perform transmission and reception of electric signals with other optical communication devices is mediated. The optical transmitter, the optical receiver, and the detection means, one or a plurality of electrical transmitters and electrical receivers for transmitting and receiving electrical signals, and converting the optical signals received by the optical receiver into electrical signals And a photoelectric conversion unit that converts an electrical signal received by the electrical reception unit into an optical signal, and communication between the one or more optical communication devices and one or more devices that transmit and receive electrical signals The in-vehicle communication system according to claim 1, further comprising a photoelectric conversion device that mediates the above. A plurality of optical communication networks including the optical communication device and the photoelectric conversion device connected in a star shape around the optical distributor;
The in-vehicle communication system according to claim 4, wherein a plurality of photoelectric conversion devices of the optical communication network are connected via an electric communication line. The in-vehicle communication according to claim 5, wherein a plurality of optical communication lines connecting an optical input unit of one optical distributor and the optical communication device or the photoelectric conversion device have substantially the same length. system. 7. The optical distributor according to claim 1, wherein one or a plurality of optical couplers each having two optical input units and two optical output units are used. The vehicle-mounted communication system described in 1.

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