KR102167610B1 - Gateway apparatus for long distance can communication - Google Patents

Abstract

The present invention relates to a gateway apparatus for long distance controller area network (CAN) communication. According to the present invention, the gateway apparatus comprises: a transmission processing unit for outputting CAN messages transmitted from any one node of a plurality of nodes of an internal network to an external network through a CAN line; and a reception processing unit for receiving the CAN messages transmitted from the external network through the CAN line to filter and block CAN messages having IDs corresponding to the plurality of nodes of the internal network among the received CAN messages, and filter CAN messages having IDs not corresponding to the plurality of nodes of the internal network among the received CAN messages and transmit the same to the internal network.

Description

Gateway device for long distance CAN communication {GATEWAY APPARATUS FOR LONG DISTANCE CAN COMMUNICATION}

The present invention relates to a gateway device for long-distance CAN communication, and more particularly, by using high-speed CAN (Controller Area Network) communication to secure a longer communication distance, high-speed CAN communication lines such as buses and trains are lengthened. It relates to a gateway device for long-distance CAN communication that enables the CAN communication range to be extended.

In general, as a vehicle system is automated, communication between vehicle internal controllers is also frequently performed, and CAN (Controller Area Network) communication is generally used for vehicle internal communication.

That is, the electronic control system inside a vehicle is composed of dozens of electronic control units (ECUs) such as an engine controller, a transmission controller, a brake controller, and an airbag controller. Communication between a plurality of electronic control devices (eg ECU1 to ECU5) uses CAN communication.

Since the CAN communication has an arbitration function, CAN communication enables communication by connecting a plurality of electronic control units (ECUs) in parallel in one network using a two-stranded twisted wire (see FIG. 1).

1 is an exemplary diagram showing the configuration of a conventional general CAN communication network. Basically, according to message communication of the CAN protocol method, one network is composed of a plurality of nodes (or CAN controllers) and a common CAN bus, Each node transmits a message in a broadcasting method, and each node selects and receives the required message. In addition, messages are transmitted between each network (eg, network 1, network 2) through CAN transceivers 110 and 210.

The CAN transceivers 110 and 210 transmit and receive CAN messages through a CAN communication line. At this time, the CAN transceivers 110 and 210 have their own input terminals and their own output terminals connected in common, so that the CAN controller (or node) 100, 200 transmits a message output by itself to the CAN controller (or node) 100 , 200) It is configured so that it can be input again and check whether an error has occurred.

As described above, all CAN controllers (or nodes) 100 and 200 transmit and receive messages by using a CAN bus in common, and each CAN controller (or node) 100 and 200 transmits messages to the same network. It transmits to all nodes on the network in a broadcast manner.

And it provides its own arbitration function by message identifier.

Specifically, each CAN controller (or node) recognizes an identifier (ID) of a message, and receives only necessary messages among broadcasted messages.

For reference, the CAN communication method has the advantage of high security by applying a plurality of error detection methods (eg, Bit Error, Stuff Error, CRC Error, Form Error, Acknowledgement Error).

However, the message (i.e., CAN message) transmission and reception method used in the existing CAN communication is a square wave of CAN messages according to the CAN standard including ID, control, data, and CRC at the transmitting end (i.e., the node transmitting the message). The waveform is applied to the wire (i.e., a twisted pair of 2 strands), and when it is received by the receiving end (ie, the node receiving the message), it transmits a 1-bit ACK signal to the transmitting end to inform that the CAN message has been received.

At this time, the ACK signal is responded by any one of a plurality of nodes (eg, ECU) connected in parallel in the receiving end network.

In addition, the transmitter transmits a CAN message according to the CAN standard (i.e., standard CAN protocol), and then changes to the RX mode briefly in a specified period (i.e., for a specified period of time) in order to receive the ACK signal from the receiver. (End of Frame) is transmitted.

However, assuming that nodes of a plurality of CAN networks communicate with each other through a gateway, for example, assuming that a node in network 1 transmits a CAN message and a node in network 2 receives the CAN message, a CAN line (i.e. , 2 strands of twisted wire), the propagation delay of 5.5nsec per 1m occurs due to the propagation delay.

If this is arithmetically calculated, a propagation delay of 5.5 usec occurs when the CAN line is assumed to be 1 km. If the receiving end that received the CAN message transmits the ACK signal to the transmitting end due to this propagation delay, the transmitting end sends an ACK signal from the receiving end. In order to receive a signal, the ACK signal does not arrive within a time period for briefly changing to the RX mode (ie, for a specified period of time).

However, even if the transmitter does not receive the ACK signal within the time to change to the RX mode, it transmits the End of Frame (EOF) according to the CAN standard, and eventually receives the ACK signal while the EOF is transmitted. EOF (i.e., data consisting of 7 bits of '1') overlaps with the ACK signal (i.e., data consisting of 1 bit of '0') to cause an error frame that changes the form of EOF Let it.

2 is an exemplary diagram shown to explain the limit of the distance according to the communication speed in general CAN communication. As described above, since a propagation delay occurs as the CAN line becomes longer, an error due to the propagation delay does not occur. CAN communication must be carried out within the distance.

By the way, as shown in FIG. 2, the limit distance (Length) that does not cause an error due to the propagation delay becomes shorter as the CAN bit rate increases (ie, the higher the speed). Therefore, there is a need for a technology that can secure a long communication distance while performing high-speed CAN communication.

The background technology of the present invention is disclosed in Korean Patent Publication No. 10-2017-0024310 (published on Mar. 7, 2017, a communication network, a vehicle including the same, and a control method thereof).

According to an aspect of the present invention, the present invention was created to solve the above problems, and a system in which CAN communication lines such as buses and trains are lengthened by ensuring a longer communication distance while using high-speed CAN communication. The purpose of this is to provide a gateway device for long-distance CAN communication that enables the high-speed CAN communication distance to be extended.

A gateway device for long-distance CAN communication according to an aspect of the present invention includes: a transmission processing unit for outputting a CAN message transmitted from any one of a plurality of nodes of an internal network to an external network through a CAN line; And receiving a CAN message transmitted from an external network through the CAN line, filtering and blocking CAN messages having IDs corresponding to a plurality of nodes of the internal network among the received CAN messages, And a reception processing unit for filtering only CAN messages having IDs that do not correspond to a plurality of nodes of the internal network and transmitting them to the internal network.

In the present invention, the gateway device for long-distance CAN communication is implemented such that an internal network is connected to one side and two channels of CAN lines are connected to the other side, and the two channels are CAN lines used for transmission and reception, respectively. It features.

In the present invention, the transmission processing unit is implemented to output only CAN messages to be transmitted from the internal network to the external network through the CAN line without receiving an ACK signal from the external network through the CAN line.

In the present invention, the transmission processing unit comprises: a first CAN transceiver for receiving a CAN message to be transmitted from an internal network; And a second CAN transceiver for receiving a CAN message output through an output terminal of the first CAN transceiver through an input terminal and outputting the CAN message to an external network through a CAN line.

In the present invention, in order to make the signal input to the input terminal of the first CAN transceiver at a signal level that does not affect the CAN message output from the internal network, the input terminal of the first CAN transceiver is powered by a pull-up resistor. It is characterized by being connected to (Vdd).

In the present invention, the second CAN transceiver only outputs a CAN message to be transmitted from the internal network to the CAN line, and does not output it to the internal network even if it receives data from an external network connected to the CAN line. The output terminal of the second CAN transceiver is characterized in that it is opened.

In the present invention, the reception processing unit includes a third CAN transceiver for receiving a CAN message from an external network through a CAN line; A controller configured to receive a CAN message output from the third CAN transceiver and perform ID filtering; And a fourth CAN transceiver configured to receive a CAN message that is ID filtered and output by the control unit and outputs it to an internal network.

In the present invention, the input terminal of the third CAN transceiver is configured so that it is not connected to the control unit so that the ACK signal is not output to the CAN line, and the signal input to the input terminal of the third CAN transceiver is In order to achieve a signal level that does not affect CAN messages received through the line, the input terminal of the third CAN transceiver is connected to the power supply Vdd by a pull-up resistor.

In the present invention, the control unit analyzes the ID of the CAN message received through the CAN line through the ID filtering to block the CAN message corresponding to the ID of the node included in the internal network from being transmitted to the internal network. Characterized in that.

In the present invention, the input terminal of the fourth CAN transceiver is connected to the output terminal of the control unit, and the output terminal of the fourth CAN transceiver is open or connected to the output terminal of the control unit.

In the present invention, the control unit updates the ID list for the node of the internal network and stores it in the internal memory, and when a CAN message is received through the channel for reception of the CAN line, the control unit stores the ID list for the node of the internal network. With reference, it is checked whether the ID of the received CAN message is the ID of the internal network, and if the ID of the received CAN message is not the ID of the internal network, the received CAN message is determined as a CAN message transmitted from the external network. It is characterized in that the received CAN message is delivered to an internal network.

In the present invention, if the ID of the received CAN message is the ID of the internal network, the control unit determines that the received CAN message is a CAN message transmitted from the internal network and does not deliver the received CAN message to the internal network. It is characterized by discarding without.

In the present invention, the internal network refers to a network directly connected to a gateway, and the external network is not directly connected to the gateway, but refers to a network connected through a CAN line.

According to an aspect of the present invention, the present invention enables high-speed CAN communication to be used and a long communication distance to be secured, thereby extending the possible high-speed CAN communication distance in a system in which CAN communication lines such as buses and trains are lengthened. .

1 is an exemplary view showing the configuration of a conventional general CAN communication network.
2 is an exemplary diagram illustrating a limit of a distance according to a communication speed in general CAN communication.
3 is an exemplary view showing a schematic configuration of a gateway device for long-distance CAN communication according to an embodiment of the present invention.
4 is an exemplary view showing the configuration of a CAN communication network configured using the gateway device for long-distance CAN communication shown in FIG. 3.
5 is a flowchart illustrating a method of controlling a gateway device for long-distance CAN communication according to an embodiment of the present invention.

Hereinafter, an embodiment of a gateway device for long distance CAN communication according to the present invention will be described with reference to the accompanying drawings.

In this process, the thickness of the lines or the size of components shown in the drawings may be exaggerated for clarity and convenience of description. In addition, terms to be described later are terms defined in consideration of functions in the present invention and may vary according to the intention or custom of users or operators. Therefore, definitions of these terms should be made based on the contents throughout the present specification.

3 is an exemplary view showing a schematic configuration of a gateway device for long-distance CAN communication according to an embodiment of the present invention, and FIG. 4 is a configuration of a CAN communication network configured using the gateway device for long-distance CAN communication shown in FIG. This is an example diagram shown.

Referring to FIG. 3, the gateway device GW for long-distance CAN communication according to the present embodiment includes a transmission processing unit 310 and a reception processing unit 320.

In addition, in the gateway device GW for long-distance CAN communication according to the present embodiment, an internal network is connected to one side and a CAN line of two channels (channel 1, channel 2) is connected to the other side.

The internal network consists of a plurality of nodes (or CAN controllers) and a common CAN bus.

The CAN lines of the two channels (channel 1, channel 2) are used for transmission or reception for each gateway device connected to both sides. For example, referring to FIG. 4, the first gateway device GW1 uses channel 1 for transmission, the second gateway device GW2 uses channel 1 for reception, and the second gateway device GW2 is channel 2 Is used for transmission, and the first gateway device GW1 uses channel 2 for reception.

At this time, the first gateway GW1 and the second gateway GW2 have the same structure as shown in FIG. 3.

Referring back to FIG. 3, the transmission processing unit 310 transmits a CAN message transmitted from any one node among a plurality of nodes (or CAN controllers) of the internal network through a transmission channel. At this time, the transmission processing unit 310 is configured not to receive an ACK signal from an external network through a CAN line, and is configured to transmit a CAN message only to an external network through a CAN line.

To this end, the transmission processing unit 310 is configured by connecting a plurality of CAN transceivers 311 and 312, and includes a first CAN transceiver 311 for receiving a CAN message from an internal network; And a second CAN transceiver 312 for receiving a CAN message output through an output terminal out of the first CAN transceiver 311 through an input terminal in and outputting the CAN message to an external network through a CAN line. do.

At this time, the input terminal (in) of the first CAN transceiver 311 is connected to the power supply (Vdd) through a pull-up resistor to achieve a signal level that does not affect the CAN message output from the internal network.

In addition, the second CAN transceiver 312 outputs a CAN message to be transmitted from the internal network to the CAN line, but does not receive data (eg, an ACK signal) from an external network connected to the CAN line (or an ACK signal). Since there is no need to receive from an external network), the output terminal out of the second CAN transceiver 312 is opened.

At this time, the reason why it is not necessary to receive the ACK signal from the external network in this embodiment is that the CAN message output to the transmission processing unit 310 is also transmitted to the node included in the internal network, so that the CAN message is received. This is because at least one node of the internal network outputs an ACK signal and is not recognized as an error because it is received by the node that transmitted the CAN message.

In addition, the reception processing unit 320 includes a plurality of CAN transceivers 321 and 322 and a control unit 322 connected between the plurality of CAN transceivers 321 and 322 to perform ID filtering. The reception processing unit 320 receives a third CAN transceiver 321 that receives a CAN message from an external network through a CAN line and a control unit that performs ID filtering by receiving a CAN message output from the third CAN transceiver 321 ( 322), and a fourth CAN transceiver 323 that receives a CAN message that is ID filtered and output by the control unit 322 and outputs it to an internal network.

At this time, the input terminal (in) of the third CAN transceiver 321 is configured so that it cannot output an ACK signal by separating it from the control unit 322, and instead, it is connected to a power source (Vdd) and a pull-up resistor through a CAN line. Make it a signal level that does not affect incoming CAN messages.

In addition, the control unit 322 receives a CAN message and performs ID filtering (see FIG. 5). Through the ID filtering, the controller 322 analyzes the ID (i.e., CAN_ID) of the CAN message received through the CAN line, and blocks the CAN message corresponding to the ID of the node included in the internal network (i.e., internal Block from being transmitted to the network).

In addition, the fourth CAN transceiver 323 receives a CAN message that is ID filtered and output by the control unit 322 and outputs it to an internal network. Accordingly, the input terminal (in) of the fourth CAN transceiver 323 is connected to the output terminal of the control unit 322. However, the output terminal out of the fourth CAN transceiver 323 may be opened or connected to the output terminal of the controller 322.

This is because the output terminal out of the fourth CAN transceiver 323 is connected to the output terminal of the control unit 322 and thus does not affect the operation of the control unit 322.

In addition, the second CAN transceiver 312 outputs a CAN message to be transmitted from the internal network to the CAN line, but does not receive data (eg, an ACK signal) from an external network connected to the CAN line (or an ACK signal). Since there is no need to receive from an external network), the output terminal out of the second CAN transceiver 312 is opened.

At this time, the reason why it is not necessary to receive the ACK signal from the external network in this embodiment is that the CAN message output to the transmission processing unit 310 is also transmitted to the node included in the internal network, so that the CAN message is received. This is because at least one node of the internal network outputs an ACK signal and is received by the node that transmitted the CAN message.

Hereinafter, a long-distance CAN communication method using the long-distance CAN communication gateway device (GW) will be described with reference to FIG. 4.

Referring to FIG. 4, the internal network of the first gateway GW1 (that is, the network to which the gateway is directly connected) becomes network 1, and the internal network of the second gateway GW2 becomes network 2. In addition, the gateway is not directly connected, and the network connected through CAN lines (channels 1 and 2) becomes an external network.

At this time, assuming that any one node of network 2 connected to the second gateway (GW2) transmits a CAN message, the transmission processing unit 310 of the second gateway (GW2) is in its own internal network (network 2). It transmits the transmitted CAN message to its external network (network 1) through the CAN line (channel 2). Accordingly, the reception processing unit 320 of the first gateway (GW1) connected to the network 1 receives the CAN message transmitted through the CAN line (channel 2), performs ID filtering, and sends it from its external network (network 2). It selects only CAN messages and outputs them to its own internal network (Network 1).

Conversely, assuming that any one node of network 1 connected to the first gateway (GW1) transmits a CAN message, the transmission processing unit 310 of the first gateway (GW1) is in its own internal network (network 1). The CAN message to be transmitted is transmitted to its external network (Network 2) through the CAN line (Channel 1). Accordingly, the reception processing unit 320 of the second gateway (GW1) connected to the network 2 receives the CAN message transmitted through the CAN line (channel 1), performs ID filtering, and sends it from its external network (network 1). It selects only CAN messages and outputs them to its own internal network (Network 2).

5 is a flowchart illustrating a control method of a gateway device for long-distance CAN communication according to an embodiment of the present invention.

5, the control unit 322 of the gateway device (GW) for long-distance CAN communication according to the present embodiment updates the list of IDs (ie, CAN_IDs) for nodes of the internal network and stores them in an internal memory (not shown). (S101).

At this time, the list of IDs (ie, CAN_IDs) for the nodes of the internal network is periodically updated or when a node of the internal network is changed.

And when a CAN message is received through a channel for reception of a CAN line, the control unit 322 checks whether the ID of the received CAN message (ie, CAN_ID) is an ID of the internal network (ie, CAN_ID) (S102).

At this time, the control unit 322 refers to an ID (ie, CAN_ID) list for a node of the internal network to check the ID (ie, CAN_ID) of the CAN message.

As a result of the check (S102), if the ID of the received CAN message (ie, CAN_ID) is not the ID of the internal network (ie, CAN_ID) (No in S102), the controller 322 returns the received CAN message It is determined as a CAN message transmitted from the network and transfers the received CAN message to the internal network (S104).

On the other hand, as a result of the check (S102), if the ID (i.e., CAN_ID) of the received CAN message is the ID of the internal network (i.e., CAN_ID) (example of S102), the CAN message currently transmitted from the internal network is returned again. In this case, the controller 322 determines that the received CAN message is a CAN message transmitted from the internal network and does not transmit the received CAN message to the internal network (S103).

As described above, in the present embodiment, an error that may occur when the CAN message output from the node included in the internal network of the gateway device (GW) is transmitted to the external network at high speed and then returned to the internal network. There is an effect that can be prevented through filtering.

In addition, the present embodiment has an effect of extending the possible high-speed CAN communication distance in a system in which a CAN communication line such as a bus or a train is lengthened by ensuring a long communication distance while using high-speed CAN communication.

As described above, the present invention has been described with reference to the embodiments shown in the drawings, but these are only exemplary, and those of ordinary skill in the field to which the technology pertains, various modifications and other equivalent embodiments are possible. I will understand the point. Therefore, the technical protection scope of the present invention should be determined by the following claims. Also, the implementation described herein may be implemented in, for example, a method or process, an apparatus, a software program, a data stream or a signal. Although discussed only in the context of a single form of implementation (eg, only as a method), the implementation of the discussed features may also be implemented in other forms (eg, an apparatus or program). The device may be implemented with appropriate hardware, software and firmware. The method may be implemented in an apparatus such as a processor, which generally refers to a processing device including, for example, a computer, microprocessor, integrated circuit or programmable logic device, or the like. Processors also include communication devices such as computers, cell phones, personal digital assistants ("PDAs") and other devices that facilitate communication of information between end-users.

GW: gateway device 310: transmission processing unit
320: reception processing unit 311, 312, 321, 323: CAN transceiver
322: control unit

Claims (13)

A transmission processing unit for outputting a CAN message transmitted from any one node among a plurality of nodes of the internal network to an external network through a CAN line; And
By receiving a CAN message transmitted from an external network through the CAN line, among the received CAN messages, CAN messages having IDs corresponding to a plurality of nodes of the internal network are filtered and blocked, and the received CAN message Including; a reception processing unit for filtering only CAN messages having IDs that do not correspond to a plurality of nodes of the internal network and transmitting them to the internal network;
The transmission processing unit,
A first CAN transceiver for receiving a CAN message to be transmitted from an internal network; And a second CAN transceiver configured to receive a CAN message output through an output terminal of the first CAN transceiver through an input terminal and output it to an external network through a CAN line,
In order to make the signal input to the input terminal of the first CAN transceiver at a signal level that does not affect the CAN message output from the internal network, the input terminal of the first CAN transceiver is connected to the power supply (Vdd) by a pull-up resistor. And
The second CAN transceiver only outputs a CAN message to be transmitted from the internal network to the CAN line, and does not output it to the internal network even when data is received from an external network connected to the CAN line. Gateway device for long-distance CAN communication, characterized in that the output terminal is opened.
The method of claim 1, wherein the gateway device for long-distance CAN communication,
On one side, the internal network is connected,
The other side is implemented to connect 2 channels of CAN line,
The two channels are gateway device for long-distance CAN communication, characterized in that each CAN line is used for transmission and reception.
The method of claim 1, wherein the transmission processing unit,
Without receiving ACK signal from external network via CAN line,
A gateway device for long-distance CAN communication, characterized in that it is implemented to output only CAN messages to be transmitted from the internal network to the external network through the CAN line.
delete delete delete The method of claim 1, wherein the reception processing unit,
A third CAN transceiver for receiving a CAN message from an external network through a CAN line;
A controller configured to receive a CAN message output from the third CAN transceiver and perform ID filtering; And
And a fourth CAN transceiver configured to receive a CAN message that is ID filtered and output by the controller and outputs it to an internal network.
The method of claim 7,
The input terminal of the third CAN transceiver is configured so that it is not connected to the control unit so that the ACK signal is not output to the CAN line.
In order to make the signal input to the input terminal of the third CAN transceiver at a signal level that does not affect the CAN message received through the CAN line,
The gateway device for long-distance CAN communication, characterized in that the input terminal of the third CAN transceiver is connected to a power source (Vdd) by a pull-up resistor.
The method of claim 7, wherein the control unit,
Through the ID filtering,
A gateway device for long-distance CAN communication, characterized in that blocking the CAN message corresponding to the ID of a node included in the internal network from being transmitted to the internal network by analyzing the ID of the CAN message received through the CAN line.
The method of claim 7,
The input terminal of the fourth CAN transceiver is connected to the output terminal of the control unit,
The gateway device for long-distance CAN communication, characterized in that the output terminal of the fourth CAN transceiver is opened or connected to the output terminal of the control unit.
The method of claim 7, wherein the control unit,
Updates the ID list of nodes in the internal network and stores them in the internal memory,
When a CAN message is received through the receiving channel of the CAN line, it is checked whether the ID of the received CAN message is the ID of the internal network by referring to the ID list for the node of the internal network,
If the ID of the received CAN message is not the ID of the internal network, the received CAN message is determined as a CAN message transmitted from an external network and the received CAN message is transmitted to the internal network. Device.
The method of claim 11, wherein the control unit,
If the ID of the received CAN message is the ID of the internal network,
A gateway device for long-distance CAN communication, characterized in that the received CAN message is determined as a CAN message transmitted from an internal network, and the received CAN message is discarded without being transmitted to the internal network.
The method of claim 1,
The internal network refers to a network directly connected to the gateway, and the external network refers to a network connected through a CAN line without being directly connected to the gateway.

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