KR20110024216A - Can communication network system and method for changing priority of can message - Google Patents

Abstract

The present invention relates to a can communication network system for changing an identifier included in a can message according to a vehicle state and a method of changing can message priority. The present invention relates to a CAN bus for relaying communication between a plurality of nodes in a CAN (Controller Area Network) communication method; And a electronics controller connected to each of the CAN buses to transmit and receive a CAN message to each other to form the node, wherein the electronics controller changes an identifier of a CAN message to be transmitted according to the vehicle status information, and changes the vehicle status information. It is characterized in that whether to accept the received can message according to. According to the present invention, it is possible to preferentially transmit important can messages according to the vehicle status and situation, thereby speeding up the response speed of the required functional operation according to the vehicle status, and providing the can message according to the driving state or environment of the vehicle. There is an advantage in that the canvas load can be reduced by adjusting the frequency of message generation according to the importance.

Can (Controller Area Network), Bus, Electronics, Load

Description

CAN COMMUNICATION NETWORK SYSTEM AND METHOD FOR CHANGING PRIORITY OF CAN MESSAGE}

The present invention relates to a can communication network system and a method of changing can message priority. More specifically, a can communication network system capable of increasing the response speed of an electronic device according to a vehicle state by varying an identifier included in a can message according to a vehicle state. And a method for changing can message priority.

In recent years, many electric appliances are provided in a vehicle. This is not only related to the vehicle driving function, but also to provide various convenience functions and advanced functions. In addition, in recent years, the components that used to operate in a mechanical manner have recently been replaced by electronically operated configurations. Furthermore, various sensors installed in a vehicle automatically detect a vehicle state and automatically control systems accordingly. It has come to be equipped with a large number.

Accordingly, the number of communication between each of these sensors and electronic devices has greatly increased in the vehicle, and thus an efficient communication technology is required. In addition, CAN (Controller Area Network) communication is generally used as the representative communication method.

However, such can communication has a fixed identifier assigned to a message transmitted between each electronic device, and the message transmission priority is fixed according to the size of the fixed identifiers. There was a disadvantage that the message transmission and reception is not made. In addition, the electronic device function that requires a quick response according to the vehicle driving condition or environment is pushed down in the transmission competition with other messages by the message transmission at a fixed priority, there is a disadvantage that the fast function performance is not achieved.

In addition, by generating and transmitting a can message, which always varies in importance according to the vehicle driving state or environment, there is a disadvantage that it causes an increase in the load of the canvas depending on the vehicle state.

Accordingly, the present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a can communication network system and can that can quickly operate the electronics function that requires a quick response according to the vehicle driving conditions or environment It provides a way to change the message priority.

Another object of the present invention is to provide a can communication network system and a method of changing can message priority, in which a transmission priority of a can message can be actively changed according to a vehicle driving state or environment.

It is still another object of the present invention to provide a can communication network system and a can message priority changing method capable of reducing can bus load by adjusting a generation period of a can message according to a vehicle driving condition or environment.

According to a feature of the present invention for achieving the above object, the present invention provides a CAN bus for relaying communication between a plurality of nodes in a CAN (Controller Area Network) communication scheme; And a electrical equipment controller connected to each of the CAN buses to transmit and receive a CAN message to each other to form the node, wherein the electronics controller changes an identifier of a CAN message to be transmitted according to vehicle status information, Accordingly, it is determined whether the received can message is accepted.

The system may further include a CAN bus controller for controlling the CAN message transmission and reception of the CAN bus and receiving vehicle status information and transmitting identifier change information of the CAN message according to the current vehicle status to all nodes connected to the CAN bus. It can be configured.

The vehicle state information may include one or more of vehicle speed, brightness, temperature, and precipitation.

In addition, the identifier change information may be information on an identifier range allocated to a CAN message associated with each node according to a current vehicle state.

On the other hand, the present invention comprises the steps of determining the current vehicle state by comparing the vehicle state value and the set value; Generating control data; Determining an identifier of a can message including the control data according to the determined vehicle state; Generating a can message comprising the determined identifier and the generated control data; And transmitting the generated can message.

The method of changing the can message priority may further include determining whether to accept the received can message according to the determined vehicle state.

As described in detail above, according to the CAN communication network system and the CAN message priority changing method according to the present invention, the following effects can be expected.

That is, since important can messages can be preferentially transmitted according to the vehicle state and situation, there is an advantage that the response speed of the required functional operation can be increased according to the vehicle state.

In addition, the can communication network system and the can message priority change method according to the present invention have an advantage in that the can bus load can be reduced by adjusting the frequency of message generation according to the importance of the can message according to the driving state or environment of the vehicle.

Hereinafter, with reference to the accompanying drawings a specific embodiment of the can message priority change method according to the present invention as described above will be described in detail.

1 is a block diagram schematically illustrating a configuration of a can communication network, FIG. 2 is an exemplary diagram illustrating a relationship between a can message identifier and a can bus occupancy in a plurality of nodes on a can communication network, and FIG. 3 is a can message A diagram showing the structure of the.

As shown in FIG. 1, a CAN (Controller Area Network) communication network includes a CAN bus 20 to which a plurality of nodes 10a to 10d and a plurality of nodes are connected. . At this time, each node is composed of controllers of the electrical equipment to control each electronic device provided in the vehicle and transmit and receive data with each other.

The CAN communication network is a multi-master network (Multi Master Network) as shown in FIG. 1 and is a communication of a carrier sense multiple access / collision detection with arbitration on message priority (CSMA / CD + AMP) scheme.

A plurality of nodes on a can communication network exchange CAN messages via the can bus 20. Each node first determines whether the can bus 20 is in use and transmits a can message, and then transmits a message while detecting whether there is a collision between the can messages. At this time, the CAN message transmitted from each node does not include the address of the sender or the receiver. Instead, an 11-bit or 29-bit identifier (ID) is included in the can message, and each node determines whether to accept the can message through the identifier included in the received can message.

That is, after all nodes connected to the network receive the CAN message on the network, the node evaluates whether the message is needed by the identifier, and then takes only the message of the identifier required by the node. Is ignored.

When can messages of several nodes flowing on the can bus 20 flow into a node that a user needs at the same time, the node compares the number of identifiers and prioritizes the can message to take first. Here, the priority of the can message is higher the lower the number of identifiers.

As shown in FIG. 2, when nodes a, b, and c simultaneously transmit a can message through the can bus 20, all of the first bits are output as dominant (0) to start the can message. Display.

The identifier information included in the CAN message is output. In this case, the identifier is generally referred to as an arbitration ID, and thus, an area in which the identifier information is displayed is described as an arbitration region in the drawing.

Looking at the signal of the first bit output from the start point of the arbitration region, in the example of FIG. 2, the recessive state 1 is output from all nodes. Therefore, the recessive state 1 is also output in the can bus. In the next bit signal, the nodes a, b, and c all output the dominant state (0). Therefore, the dominant state (0) is also output in the canvas.

However, since the dominant state 0 is output at node A and c while the recessive state 1 is output at node b, the dominant state 0 is output along the nodes a and c at the CAN bus. Thus, from point A, node b is pushed out of priority.

Then again at point B, node a outputs dominant state (0), while node c outputs recessive state (1), so the can bus outputs dominant state (0) according to node a, so that node a You win the arbitration and use the canvas as your first priority.

That is, the identifiers included in each can message transmitted from each node a, b, and c are different from each other, and the node transmitting the can message having the lowest number of identifiers occupies the can bus. Therefore, if you want to change the transmission priority of the can message, you must change the identifier included in the can message.

Looking at the structure of the can message in more detail, as shown in Fig. 3, first, it starts from the start of frame (SOF) area indicating the start point of the can message. The frame start area is located at the top of the frame and has a default value of "0".

An arbitration field indicating the identifier information described above is provided. The arbitration area has 11 bits in the standard message and 29 bits in the extended message.

Also followed by the arbitration area is a Remote Transfer Request (RTR) bit, which has a default "0" and indicates that the can message is a data frame when the bit value is "0". Conversely, if the bit value is "1", it means that the CAN message is a Remote Transmission Request (RTR) frame. Here, the remote transmission request frame is used to request transmission of data from one node to another on the data bus.

In addition, a 6-bit Control Field is configured and R0, R1, with two "0" values reserved for future use, and a 4-bit data length code (DLC: Data) indicating the number of bytes in the data field. Length Code).

Next, the data field contains data to be transferred from one node to another, and is composed of 0 to 8 bytes.

In addition, the CRC (CRC: Cyclic Redundancy Check) region has a cyclic redundancy check (CRC) code followed by a bit having a value of "1" indicating the end of a data field. ACKnowledge field is composed of 2 bits, and the first bit is a slot bit having a value of "0", and is written as a value of "1" transmitted from another node that has successfully received a message. Can be. The second bit has a value of "1".

Finally, the End Of Frame File (EOF) consists of 7 bits and all have a value of "1". Subsequently, the CAN bus recognizes the end of the can message and enters an Idle state by means of a 3-bit frame interrupt field (INTermission Field) having a value of "1".

In such a can communication scheme, a fixed identifier is used as previously described. That is, when data is to be transmitted from one node to another node, a predetermined identifier is sent to the arbitration area of the can message according to the data content to be transmitted, and the node receiving the node recognizes the predetermined identifier and It was determined whether to accept the can message containing the identifier.

However, the present invention does not use such a fixed identifier, but uses an identifier that varies depending on the situation of the system. This will be described in more detail with reference to FIG. 4.

4 is a flowchart illustrating a method of changing a can message identifier according to a specific embodiment of the present invention.

First, a specific embodiment of the present invention starts from the step of generating control data to be transmitted from one node to another node automatically according to the driving state of the vehicle, the driving environment, or the like (S100). In this case, the control data may include a command for controlling the operation of the electronic device corresponding to the node to receive it, or may include information used to control the electronic device.

That is, for example, the control data may be a control command for transmitting from the input panel on the front of the vehicle interior to the vehicle air conditioner control unit, and transmitted from the indoor temperature sensor for detecting the vehicle indoor temperature to the air conditioner control unit of the vehicle. It may also be the temperature information inside the vehicle.

When such control data is generated in a specific node, the current vehicle state value and the set value are compared (S110). For example, if the set value for the vehicle speed is 40km / h, it is determined whether the current vehicle speed value is more than or less than 40km / h. In another example, it is determined whether the current luminance is high or low compared to the set value. In addition to the above example, the vehicle state value may be any value representing information related to a vehicle driving state or driving environment such as precipitation and temperature.

The identifier of the can message to be transmitted is determined according to the comparison result in operation 110 above. For example, if it is detected that the speed of the vehicle during the night driving exceeds the set value, in order to increase the priority of the vehicle headlight control-related can message, the identifier of the arbitration area in the can message is set lower than usual.

The priority of changing the identifier of the can message to be transmitted according to the comparison result of the vehicle state value and the set value is because the type of information or command to be transmitted more quickly varies according to the vehicle state.

Recently, a wide variety of electronic devices are provided inside a vehicle, and each electronic device communicates with each other as each node on a can network. Here, since only one can bus is difficult to relay communication between all the electronic devices provided in the vehicle, a plurality of CAN classes are provided in a general vehicle.

For example, class A, related to convenience or advanced features such as electronic boot releases, electric mirror controls, rain detection, sunroof, weather management, power windows, seat controls, instrument information, etc. Class B for general transmission, class C used for real-time control requiring fast response times such as power train, stability control (ABS, traction control, active suspension), engine management, shifting, Internet, digital TV and Class D can be used for the same application, and each class uses a separate canvas.

In each can class as described above, communication for controlling a plurality of electronic devices is performed, and some of the electronic devices included in one class have a response speed required according to a vehicle environment and a vehicle state as described above. Since different can classes in each can class, the identifier of the can message associated with the control of a particular electronic device is set differently depending on the situation, and thus the priority of the message is changed.

As described above, after differently determining the identifier included in the can message according to the vehicle state in step 130, the node generates the can message including the control data generated in step 100 and the identifier determined in step 130. (S150).

The control data intended to be transmitted is processed at the specific node by transmitting the generated can message through the can bus (S170).

In a further embodiment, the higher priority can message may be transmitted more frequently by lowering the transmission period, and the lower priority can message may be increased. If the priority is changed, the priority of the can message, that is, the identifier indicates the importance of the can message in the current vehicle state, and thus the transmission period of the can message can be increased for quick response of the electronic device related to the can message. . For example, at night when the vehicle's visibility is difficult (for example, when the brightness is below a set value), the can message transmitted from the precipitation sensor to the wiper and the can delivered from the precipitation sensor to the wiper are increased at the same time. The frequency of messages is also increased to ensure vehicle visibility.

Referring to a specific example of the can communication priority changing method as shown in FIG. 4 described above, as an example, since the necessity of securing the driver's vision increases as the vehicle is traveling at a high speed, the speed of the vehicle may be For example, 40 km / h or more, it is preferred over can messages associated with other electronic equipment of the same class by varying the identifier of the arbitration area of the can message delivered to the wiper and the wiper operating in the automatic control mode to a lower number range. In this case, the field of view is secured more securely.

As another example, in the GPS receiver for reading the position of the vehicle, when the vehicle speed is high, the vehicle is difficult to change direction sharply, and thus the probability of maintaining the current traveling direction is high. Therefore, when the vehicle speed is greater than or equal to the set value, the priority of the coordinate-related can message among the GPS device-related can messages may be lowered, and the priority may be increased by lowering the identifier of the altitude-related can message. In addition, when the vehicle speed is higher than the set value, the load of the canvas can be reduced by lowering the transmission frequency of the coordinate-related can message.

In this case, in order for the receiving side to be able to confirm the property change of the data as the identifier is changed, a specific value may be assigned to the data area to recognize that the identifier is changed.

Alternatively, the CAN bus controller which controls the CAN bus compares the state value and the set value of the vehicle, and transfers the identifier change information according to the current state of the vehicle to each node in a batch so that the identification and recognition of the identifier according to the current state is achieved. You can also make it all possible.

That is, in can class A, for example, if the speed is above the set value, an identifier from 0x0 to 0x200 is assigned to the wiper related can message, and if it is below the set value, an identifier from 0x201 to 0x250 is assigned to the wiper related can message. If you assign an identifier from 0x0 to 0x200 to another electronic device can message, the canvas controller informs all nodes of the can class of the identifier assignment status according to the result of comparing the vehicle's speed with the set value. Appropriate identifiers are assigned to the can messages according to the vehicle status, and when the can message is received and the decision is made to accept the message, the can message for the can message with the changed identifier is recognized by the identifier assignment status that is collectively informed by the canvas controller. You should also be able to judge correctly.

The rights of the present invention are not limited to the embodiments described above, but are defined by the claims, and those skilled in the art can make various modifications and adaptations within the scope of the claims. It is self-evident.

1 is a block diagram schematically showing the configuration of a can communication network;

2 illustrates an example of a relationship between a can message identifier and a can bus occupancy in a plurality of nodes on a can communication network.

3 illustrates the structure of a can message.

4 is a flowchart illustrating a method of changing can message priority according to a specific embodiment of the present invention.

Claims (8)

A CAN bus for relaying communication between a plurality of nodes in a CAN (Controller Area Network) communication scheme; And A electronics controller connected to each of the CAN buses to transmit and receive CAN messages to each other to form the nodes, respectively; And the electronics controller changes the identifier of the can message to be transmitted according to the vehicle status information and determines whether to accept the received can message according to the vehicle status information. The method of claim 1, The system comprises: And a CAN bus controller for controlling the CAN message transmission and reception of the CAN bus and receiving vehicle status information and transmitting identifier change information of the CAN message according to the current vehicle status to all nodes connected to the CAN bus. Can communication network system. The method of claim 2, The vehicle state information, A can communication network system comprising any one or more of vehicle speed, brightness, temperature and precipitation. The method according to claim 2 or 3, The identifier change information, CAN information network system according to the current vehicle status, characterized in that the information on the assigned identifier range for the can message associated with each node. Comparing a vehicle state value and a set value to determine a current vehicle state; Generating control data; Determining an identifier of a can message including the control data according to the determined vehicle state; Generating a can message comprising the determined identifier and the generated control data; And And transmitting the generated can message. The method of claim 5, The can message priority changing method is And determining whether to accept the received can message according to the determined vehicle condition. The method according to claim 5 or 6, The vehicle state value is, Method for changing the can message priority, characterized in that it comprises a vehicle speed. The method according to claim 5 or 6, The can message priority changing method is And changing the cycle of generating a can message according to the determined vehicle state.

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