Data transmission and interaction method of vehicle-mounted equipment based on CAN network

Abstract

The present invention relates to the field of vehicle-mounted communication technology, and discloses a vehicle-mounted device data transmission and interaction method based on a CAN network, comprising the following steps: S101, collecting messages sent by vehicle-mounted devices, and parsing them to extract vehicle operation data; S102, receiving vehicle operation data by a CAN gateway controller, extracting signal content, classifying and optimizing, and compressing and encapsulating; S103, sending the encapsulated vehicle operation data to an external terminal device; S104, the external terminal device receives and parses the encapsulated vehicle operation data; S105, a remote terminal sends an encrypted control instruction to a vehicle-mounted gateway, which is converted into a CAN message and executed after verification by the gateway, and the ECU generates a feedback signal and transmits it back, and the gateway feeds back to the remote terminal through wireless communication to complete a closed-loop interaction. The present invention ensures the real-time transmission of safety-critical data and improves the stability of wireless communication.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle-mounted communication, and in particular relates to a vehicle-mounted device data transmission and interaction method based on a CAN network. Background Art

[0002] With the rapid development of intelligent connected vehicles, the data interaction requirements of vehicle-mounted devices are becoming increasingly complex. Traditional vehicle-mounted communication networks mainly rely on the CAN bus to realize data transmission between electronic control units, sensors and actuators, but their original design was for closed communication within the vehicle, and it is difficult to directly support remote wireless interaction and cloud collaboration. In the existing technology, the vehicle-mounted gateway usually only undertakes the protocol conversion function and lacks the ability to intelligently optimize data, resulting in low wireless transmission efficiency, high latency, and significant bandwidth waste. In addition, the security of remote control commands is insufficient, the static encryption mechanism is vulnerable to attacks, and there is a lack of a two-way feedback mechanism, making it difficult to ensure the reliability of command execution.

[0003] The current in-vehicle CAN network has the following technical bottlenecks: 1. Data transmission redundancy: Traditional gateways do not prioritize and filter CAN messages, and low-value data occupies a large amount of communication resources; 2. Poor adaptability of wireless communication: Existing solutions mostly rely on a single wireless protocol and cannot dynamically switch communication methods according to the scenario, resulting in insufficient transmission stability; 3. Weak remote control security: Command transmission mostly uses fixed key encryption, which poses a risk of being intercepted or tampered with, and lacks an execution status feedback loop; 4. Lack of edge computing capabilities: Data analysis and processing are completely dependent on the cloud, and high latency makes it difficult to meet real-time requirements. Summary of the invention

[0004] The present invention provides a vehicle-mounted device data transmission and interaction method based on a CAN network, which solves the technical problems of data transmission redundancy, insufficient wireless communication adaptability, and potential communication security risks in related technologies.

[0005] The present invention provides a vehicle-mounted device data transmission and interaction method based on a CAN network, comprising the following steps:

[0006] S101, collecting messages sent by vehicle-mounted devices through the CAN bus, wherein the messages are generated by the electronic control unit ECU, sensors and actuators, and parsing them based on the communication protocol defined in the DBC file to extract vehicle operation data; in the message collection process, a hierarchical priority scheduling mechanism is used to classify the CAN data stream, high-priority messages are transmitted first, and redundant data is filtered through an intelligent data screening mechanism;

[0007] S102, the CAN gateway controller receives the vehicle operation data, extracts the signal content according to the DBC file, and optimizes it according to the vehicle functional modules; and compresses and encapsulates the optimized data through the wireless transmission module, and adopts a dynamic priority scheduling mechanism during encapsulation; wherein the vehicle functional modules include: a power system module, a body control module, and a safety warning module;

[0008] S103, sending the encapsulated vehicle operation data to the external terminal device via BLE; during the transmission process, selecting the optimal transmission channel based on the multi-dimensional channel scoring model, and dynamically adjusting the broadcast interval and sleep ratio of the external terminal device according to the data timeliness level, where the dimensions include: channel interference intensity, device density and historical transmission success rate;

[0009] S104, the external terminal device receives and parses the encapsulated vehicle operation data through the BLE connection;

[0010] S105, the remote terminal sends an encrypted control instruction to the on-board gateway. The gateway authenticates the instruction and converts it into a CAN protocol message, which is then sent to the target ECU via the CAN bus for execution. After the target ECU executes the instruction, a feedback signal is generated and returned to the gateway via the CAN bus. The gateway transmits the feedback signal back to the remote terminal via wireless communication, completing the interactive closed loop. The encrypted control instruction uses dynamic key encryption technology and a two-way confirmation mechanism.

[0011] Furthermore, the hierarchical priority scheduling mechanism includes:

[0012] 201, message ID priority is divided based on functional safety level;

[0013] 202, when an emergency event is detected, dynamically raising the priority of the associated message to the highest level;

[0014] 203, low priority messages are combined and transmitted according to a preset cycle when the bus is idle.

[0015] Furthermore, the analysis based on the DBC file in S101 includes:

[0016] 301, parsing the signal start bit, signal length, data type and scaling factor defined in the DBC file;

[0017] 302, converting binary data of the message into physical quantity values, and performing standardization processing according to signal units;

[0018] 303, adding a timestamp and a source ECU identifier to the parsed data to generate vehicle operation data.

[0019] Furthermore, the intelligent data screening mechanism includes:

[0020] 401, if the same message ID is sent repeatedly within the first preset time window and the data content does not change, only the last valid data is retained;

[0021] 402, if the fluctuation range of the sensor data in N consecutive cycles is less than the first preset threshold, it is regarded as redundant data and discarded;

[0022] 403, security-critical data is unconditionally retained and marked as high priority.

[0023] Furthermore, the dynamic priority scheduling mechanism adopts a hierarchical priority architecture, including: an emergency layer, a dynamic layer and an elastic layer, wherein the emergency layer is used to transmit safety warning data, including: collision signals, brake system fault codes, and the emergency layer data directly occupies the wireless transmission channel; the dynamic layer is used to transmit the real-time status data of the vehicle, including: vehicle speed, battery voltage and motor temperature, and the transmission order is based on the dynamic weight calculation result; the elastic layer is used to transmit non-real-time data, including: log files, software upgrade packages, and the transmission trigger condition is that the network load rate is lower than the load rate threshold;

[0024] The calculation formula of dynamic weight is:

[0025] ;

[0026] Among them, P represents the dynamic weight value, L represents the network load rate, which ranges from 0 to 1, T represents the preset data urgency, which ranges from 0 to 1 and is evaluated based on timeliness, and D represents the preset data importance value, which ranges from 0 to 1 and is evaluated based on the functional module. , and denote the first weight coefficient, the second weight coefficient and the third weight coefficient respectively, , and They represent the fourth weight coefficient, the fifth weight coefficient and the sixth weight coefficient respectively.

[0027] Furthermore, the encapsulated vehicle operation data is segmented according to the BLE MTU limit and encapsulated into a GATT characteristic value format.

[0028] Furthermore, the external terminal device receives and parses the encapsulated vehicle operation data through the BLE connection, wherein the specific steps of receiving the data include:

[0029] S501, establishing a BLE connection;

[0030] S502, receiving the encapsulated vehicle operation data in segments;

[0031] S503: Perform integrity check on the received data.

[0032] Furthermore, the two-way confirmation mechanism includes: instruction reception confirmation and execution result confirmation, wherein instruction reception confirmation includes: after receiving the encrypted instruction, the on-board gateway immediately sends an instruction reception confirmation package to the remote terminal; if the remote terminal does not receive the instruction reception confirmation package within the first preset time period, the instruction retransmission is triggered; execution result confirmation includes: after the target ECU executes the instruction, it generates an execution result message and returns it to the gateway via the CAN bus; the gateway transmits the result message back to the remote terminal through the MQTT protocol, and the remote terminal sends an execution result confirmation package after verification to complete the closed loop; if the execution result confirmation package does not arrive at the gateway within the first preset time period, the instruction execution is marked as failed and an error log is recorded.

[0033] The beneficial effects of the present invention are as follows: the present invention divides data priorities based on ISO 26262 functional safety levels, combines a dynamic priority upgrade strategy triggered by emergency events, ensures that safety-critical data occupies the transmission channel in real time, and merges low-priority data for transmission during idle periods, significantly reduces bus load and transmission conflicts, and balances real-time performance and resource efficiency;

[0034] The present invention builds an intelligent scoring model based on channel interference, device density and transmission history, dynamically selects the optimal communication channel and adapts transmission parameters, significantly improves wireless communication stability, and reduces packet loss rate and signal interference risks;

[0035] The present invention adopts dynamic key encryption and two-way confirmation mechanism to achieve end-to-end secure closed-loop control, resist replay attacks and data tampering, and ensure the reliability and compliance of remote instructions. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a flow chart of the vehicle-mounted device data transmission and interaction method based on the CAN network of the present invention. DETAILED DESCRIPTION

[0037] The subject matter described herein will now be discussed with reference to example embodiments. It should be understood that the discussion of these embodiments is only to enable those skilled in the art to better understand and implement the subject matter described herein, and the functions and arrangements of the elements discussed may be changed without departing from the scope of protection of the contents of this specification. Each example may omit, replace or add various processes or components as needed. In addition, the features described relative to some examples may also be combined in other examples.

[0038] like Figure 1 As shown, the vehicle-mounted device data transmission and interaction method based on the CAN network includes the following steps:

[0039] S101, collecting messages sent by vehicle-mounted devices through the CAN bus, wherein the messages are generated by the electronic control unit ECU, sensors and actuators, and parsing them based on the communication protocol defined in the DBC file to extract vehicle operation data; in the message collection process, a hierarchical priority scheduling mechanism is used to classify the CAN data stream, high-priority messages are transmitted first, and redundant data is filtered through an intelligent data screening mechanism;

[0040] S102, the CAN gateway controller receives the vehicle operation data, extracts the signal content according to the DBC file, and optimizes it according to the vehicle functional modules; and compresses and encapsulates the optimized data through the wireless transmission module, and adopts a dynamic priority scheduling mechanism during encapsulation; wherein the vehicle functional modules include: a power system module, a body control module, and a safety warning module;

[0041] S103, sending the encapsulated vehicle operation data to the external terminal device via BLE; during the transmission process, selecting the optimal transmission channel based on the multi-dimensional channel scoring model, and dynamically adjusting the broadcast interval and sleep ratio of the external terminal device according to the data timeliness level, where the dimensions include: channel interference intensity, device density and historical transmission success rate;

[0042] S104, the external terminal device receives and parses the encapsulated vehicle operation data through the BLE connection;

[0043] S105, the remote terminal sends an encrypted control instruction to the on-board gateway. The gateway authenticates the instruction and converts it into a CAN protocol message, which is then sent to the target ECU via the CAN bus for execution. After the target ECU executes the instruction, a feedback signal is generated and returned to the gateway via the CAN bus. The gateway transmits the feedback signal back to the remote terminal via wireless communication, completing the interactive closed loop. The encrypted control instruction uses dynamic key encryption technology and a two-way confirmation mechanism.

[0044] In one embodiment of the present invention, the message refers to a data unit transmitted through the CAN bus, which contains a group of signals in a specific format. The message consists of an identifier ID and a data field. The identifier is used to distinguish the priority and type of the message. The data field contains specific signal values, such as vehicle speed, engine speed, etc. The message sent by the engine ECU contains signals such as engine speed, water temperature, and fuel injection amount. The message sent by the body control ECU contains signals such as door status, window position, and light switch status; CAN data stream refers to a standardized data sequence continuously transmitted on the CAN bus; vehicle operation data refers to physical quantities or status parameters obtained by parsing the message data field, including vehicle speed, engine speed, fault code, etc.

[0045] In one embodiment of the present invention, the hierarchical priority scheduling mechanism includes:

[0046] 201. Prioritize message IDs based on functional safety levels. Specifically, the functional safety level refers to the ISO 26262 functional safety level. Prioritize messages based on the functional safety level to ensure real-time transmission of safety-critical data and reduce response delays.

[0047] 202, when an emergency event is detected, dynamically increase the priority of the associated message to the highest level to enhance the system's ability to respond to sudden risks. For example, under normal conditions, the battery temperature message priority is ASIL B. When the battery temperature is >100°C, the message priority is dynamically increased to ASIL D.

[0048] 203. Low-priority messages are combined and transmitted according to a preset cycle when the bus is idle, which can optimize bandwidth utilization, reduce bus load, balance real-time performance and resource efficiency, and meet automotive-grade safety and performance requirements. For example, the door status + air conditioning settings + light signals can be combined into the same message.

[0049] In one embodiment of the present invention, the parsing based on the DBC file in S101 includes:

[0050] 301, parsing the signal start bit, signal length, data type and scaling factor defined in the DBC file to provide a unified input for subsequent processing;

[0051] 302, converting the binary data of the message into a physical quantity value, and performing standardization processing according to the signal unit to solve the problem of inconsistency of multi-source data units;

[0052] 303, adding a timestamp and a source ECU identifier to the parsed data to generate vehicle operation data. The source ECU identifier indicates the ECU ID of the source of the marked data, such as 0x0C1 representing the engine ECU.

[0053] In one embodiment of the present invention, the intelligent data screening mechanism includes:

[0054] 401, if the same message ID is sent repeatedly within the first preset time window and the data content does not change, only the last valid data is retained;

[0055] 402, if the fluctuation range of the sensor data in N consecutive cycles is less than the first preset threshold, it is regarded as redundant data and discarded to reduce the transmission and storage burden. For example, when the absolute value of the tire pressure change is less than 5 kPa, it is discarded as redundant data;

[0056] 403, security-critical data is unconditionally retained and marked as high priority.

[0057] In one embodiment of the present invention, a dynamic cache queue is used for low-priority messages, and batch transmission is triggered when the queue length reaches 10 or the time window times out. The cache threshold is dynamically adjusted according to the real-time load rate of the CAN bus. For example, when the load rate is greater than or equal to 70%, the cache threshold is adjusted to 5, and when the load rate is less than 30%, the cache threshold is adjusted to 15.

[0058] The DBC file refers to a standard configuration file used to describe the CAN bus communication protocol, which defines the physical meaning, data structure and parsing rules of the signals in the CAN message, and is used to convert the raw binary data on the CAN bus into readable engineering values, such as vehicle speed, temperature, fault code, etc.

[0059] In one embodiment of the present invention, signal content is extracted according to the DBC file and optimized by vehicle functional module classification, specifically including: power system module: extracting signals related to power control in the DBC file, such as engine speed, vehicle speed, battery SOC and motor temperature, and mapping them into the same data format; body control module: extracting door status, window position and light signals, filtering invalid status, and retaining incremental update data; safety warning module: real-time capture of ABS faults and collision sensor trigger signals, marking them as emergency data streams, and independently caching them in a high priority queue; for signals that are sent periodically and whose values ​​have not changed, only the first and last data packets are retained, and the intermediate redundant data are discarded.

[0060] In one embodiment of the present invention, the optimized data is compressed and encapsulated through a wireless transmission module. Specifically, for the real-time status data of the vehicle, the LZ4 fast compression algorithm is adopted, and for the non-real-time data, the DEFLATE high compression rate algorithm is adopted; and the block compression method is adopted to independently compress the functional modules to avoid decompression failure caused by cross-module data dependency; the encapsulation is carried out according to a custom encapsulation protocol, and the dynamic priority scheduling mechanism is adopted for transmission.

[0061] In one embodiment of the present invention, the dynamic priority scheduling mechanism adopts a hierarchical priority architecture, including: an emergency layer, a dynamic layer and an elastic layer, wherein the emergency layer is used to transmit safety warning data, the safety warning data includes: collision signals, brake system fault codes, and the emergency layer data directly occupies the wireless transmission channel; the dynamic layer is used to transmit vehicle real-time status data, the vehicle real-time status data includes: vehicle speed, battery voltage and motor temperature, and the transmission order is based on the dynamic weight calculation result sorting; the elastic layer is used to transmit non-real-time data, the non-real-time data includes: log files, software upgrade packages, and the transmission trigger condition is that the network load rate is lower than the load rate threshold;

[0062] The calculation formula of dynamic weight is:

[0063] ;

[0064] Among them, P represents the dynamic weight value, which determines the transmission order of the vehicle's real-time status data. L represents the network load rate, which ranges from 0 to 1. T represents the preset data urgency, which ranges from 0 to 1 and is evaluated based on timeliness. For example, the data urgency of safety warning data is 1, the data urgency of vehicle real-time status data is 0.6, and the data urgency of non-real-time data is 0.2. D represents the preset data importance value, which ranges from 0 to 1 and is evaluated based on functional modules. For example, the data importance value of the power system is 1, the data importance value of the body control system is 0.6, and the data importance value of the infotainment is 0.3. When , it indicates that the current scenario is high load. Exponentially amplify the weight of urgent data to ensure that critical data can still occupy bandwidth under high load. When , it indicates that the current scenario is low load. Balance the differences in data with different urgency levels, , and represent the first weight coefficient, the second weight coefficient and the third weight coefficient respectively, which are used to adjust the influence of each parameter on the priority P, and , and The sum is 1, , and denote the fourth weight coefficient, the fifth weight coefficient and the sixth weight coefficient respectively, and , and The sum is 1.

[0065] Dynamic priority can dynamically adjust the priority according to network load and data urgency in real time to ensure real-time transmission of high-timeliness data; adapt to network fluctuations, reduce the weight of non-critical data during congestion, and improve throughput efficiency during idle time; dynamically calculate weights based on historical success rate and timeliness to enhance reliability in complex scenarios; support dynamic priority upgrade of emergencies, optimize resource allocation, balance real-time and bandwidth utilization, and meet the high reliability, low latency and high performance requirements of vehicle systems.

[0066] In one embodiment of the present invention, the encapsulated vehicle operation data is sent to an external terminal device via BLE. Specifically, the data is fragmented according to the BLE MTU limit and encapsulated into a GATT characteristic value format.

[0067] In one embodiment of the present invention, the calculation formula of the channel score of the multi-dimensional channel score model is:

[0068] ;

[0069] Among them, S represents the channel score, CII represents the channel interference intensity, ED represents the device density, which is obtained by normalizing the number of active BLE devices in the current channel, and R represents the historical transmission success rate. , and denote the seventh weight coefficient, the eighth weight coefficient and the ninth weight coefficient respectively, , and The sum is 1 and is adjusted dynamically according to the network status. For example, When The weight of and ,when When The weight of and .

[0070] In one embodiment of the present invention, the external terminal device receives and parses the encapsulated vehicle operation data through a BLE connection, wherein the specific steps of receiving the data include:

[0071] S501, establishing a BLE connection;

[0072] S502, receiving the encapsulated vehicle operation data in pieces. Specifically, the vehicle gateway segments the encapsulated vehicle operation data according to the BLE MTU, adds a serial number and a CRC checksum to each piece, and the external terminal receives the data piece by piece through notification, and reassembles the complete data packet according to the serial number;

[0073] S503, perform integrity check on the received data, specifically, after repeating the complete data packet, check the CRC, if the check fails, request retransmission of a specific fragment based on the sequence number.

[0074] In one embodiment of the present invention, the specific steps of parsing data include:

[0075] S601, extracting the header, dynamic weight value, function module ID and data body according to the custom encapsulation protocol, the protocol structure is: |header|dynamic weight value|function module ID|data body|CRC32|;

[0076] S602, restore data using LZ4 decompression algorithm;

[0077] S603, classify the data according to the functional module ID and store it in the database.

[0078] In one embodiment of the present invention, S105 is used to implement secure control and closed-loop feedback of the vehicle ECU by the remote terminal, ensuring that the control instructions are sent from the remote terminal to the vehicle gateway, forwarded to the target ECU for execution after identity authentication, and the execution results are transmitted back to the remote terminal to form a complete control link; wherein, the remote terminal refers to a control center located outside the vehicle, such as the backend system of the car company, which is responsible for sending encrypted control instructions; the control instructions are encrypted using dynamic keys, such as the AES-256-GCM algorithm, and the keys are periodically updated through a two-way authentication protocol, such as TLS 1.3.

[0079] In one embodiment of the present invention, the two-way confirmation mechanism includes: instruction reception confirmation and execution result confirmation, wherein the instruction reception confirmation includes: after receiving the encrypted instruction, the on-board gateway immediately sends an instruction reception confirmation package to the remote terminal, and the instruction reception confirmation package includes the instruction hash value and timestamp generated based on the SHA-256 algorithm; if the remote terminal does not receive the instruction reception confirmation package within the first preset time period, the instruction retransmission is triggered; the execution result confirmation includes: after the target ECU executes the instruction, an execution result message is generated, and the execution result message includes a status code and parameters, which are returned to the gateway via the CAN bus; the gateway transmits the result message back to the remote terminal through the MQTT protocol, and the remote terminal sends an execution result confirmation package after verification to complete the closed loop; if the execution result confirmation package does not reach the gateway within the first preset time period, the instruction execution failure is marked and an error log is recorded, wherein the first preset time period is preferably set to 3 seconds, and the second preset time period is preferably set to 5 seconds.

[0080] The two-way confirmation mechanism ensures the end-to-end reliability of the command from sending to execution through double closed-loop verification of command reception confirmation and execution result confirmation. The command reception confirmation package provides real-time feedback on the command reception status to avoid command loss due to network packet loss; the execution result confirmation package verifies the actual execution result of the command to prevent execution failure due to ECU failure or bus conflict. This mechanism significantly reduces the uncertainty of command execution and ensures the accuracy and reliability of key control operations such as braking and power limiting.

[0081] The embodiments of the present invention are described above, but the present invention is not limited to the above-mentioned specific implementation modes. The above-mentioned specific implementation modes are merely illustrative and not restrictive. Under the guidance of the present embodiment, ordinary technicians in this field can also make many forms, which are all within the protection of the present embodiment.

Claims

1. A vehicle-mounted device data transmission and interaction method based on a CAN network, characterized in that: The following steps are involved: S101, collecting messages sent by vehicle-mounted devices through the CAN bus, wherein the messages are generated by the electronic control unit ECU, sensors and actuators, and parsing them based on the communication protocol defined in the DBC file to extract vehicle operation data; in the message collection process, a hierarchical priority scheduling mechanism is used to classify the CAN data stream, high-priority messages are transmitted first, and redundant data is filtered through an intelligent data screening mechanism; S102, the CAN gateway controller receives the vehicle operation data, extracts the signal content according to the DBC file, and optimizes it according to the vehicle functional modules; and compresses and encapsulates the optimized data through the wireless transmission module, and adopts a dynamic priority scheduling mechanism during encapsulation; wherein the vehicle functional modules include: a power system module, a body control module, and a safety warning module; The dynamic priority scheduling mechanism adopts a hierarchical priority architecture, including an emergency layer, a dynamic layer, and an elastic layer. The emergency layer is used to transmit safety warning data, including collision signals and brake system fault codes, and the emergency layer data directly occupies the wireless transmission channel; the dynamic layer is used to transmit real-time vehicle status data, including vehicle speed, battery voltage, and motor temperature, and the transmission order is based on the dynamic weight calculation result; the elastic layer is used to transmit non-real-time data, including log files and software upgrade packages, and the transmission trigger condition is that the network load rate is lower than the load rate threshold; The calculation formula of dynamic weight is: ； Among them, P represents the dynamic weight value, L represents the network load rate, which ranges from 0 to 1, T represents the preset data urgency, which ranges from 0 to 1 and is evaluated based on timeliness, and D represents the preset data importance value, which ranges from 0 to 1 and is evaluated based on the functional module. , and represent the first weight coefficient, the second weight coefficient and the third weight coefficient respectively, , and represent the fourth weight coefficient, the fifth weight coefficient and the sixth weight coefficient respectively; S103, sending the encapsulated vehicle operation data to the external terminal device via BLE; during the transmission process, selecting the optimal transmission channel based on the multi-dimensional channel scoring model, and dynamically adjusting the broadcast interval and sleep ratio of the external terminal device according to the data timeliness level, where the dimensions include: channel interference intensity, device density and historical transmission success rate; S104, the external terminal device receives and parses the encapsulated vehicle operation data through the BLE connection; S105, the remote terminal sends an encrypted control instruction to the on-board gateway. The gateway authenticates the instruction and converts it into a CAN protocol message, which is then sent to the target ECU via the CAN bus for execution. After the target ECU executes the instruction, a feedback signal is generated and returned to the gateway via the CAN bus. The gateway transmits the feedback signal back to the remote terminal via wireless communication, completing the interactive closed loop. The encrypted control instruction uses dynamic key encryption technology and a two-way confirmation mechanism.

2. The method for transmitting and interacting vehicle-mounted equipment data based on a CAN network according to claim 1, characterized in that: The hierarchical priority scheduling mechanism includes: 201, message ID priority is divided based on functional safety level; 202, when an emergency event is detected, dynamically raising the priority of the associated message to the highest level; 203, low priority messages are combined and transmitted according to a preset cycle when the bus is idle.

3. The vehicle-mounted device data transmission and interaction method based on CAN network according to claim 1 is characterized in that: The analysis based on DBC files in S101 includes: 301, parsing the signal start bit, signal length, data type and scaling factor defined in the DBC file; 302, converting binary data of the message into physical quantity values, and performing standardization processing according to signal units; 303, adding a timestamp and a source ECU identifier to the parsed data to generate vehicle operation data.

4. The vehicle-mounted device data transmission and interaction method based on CAN network according to claim 1 is characterized in that: Intelligent data filtering mechanisms include: 401, if the same message ID is sent repeatedly within the first preset time window and the data content does not change, only the last valid data is retained; 402, if the fluctuation range of the sensor data in N consecutive cycles is less than the first preset threshold, it is regarded as redundant data and discarded; 403, security-critical data is unconditionally retained and marked as high priority.

5. The vehicle-mounted device data transmission and interaction method based on CAN network according to claim 1 is characterized in that: The encapsulated vehicle operation data is fragmented according to the BLE MTU limit and encapsulated into the GATT characteristic value format.

6. The vehicle-mounted device data transmission and interaction method based on CAN network according to claim 1 is characterized in that: The external terminal device receives and parses the encapsulated vehicle operation data through the BLE connection, wherein the specific steps of receiving the data include: S501, establishing a BLE connection; S502, receiving the encapsulated vehicle operation data in segments; S503: Perform integrity check on the received data.

7. The vehicle-mounted device data transmission and interaction method based on CAN network according to claim 1 is characterized in that: The two-way confirmation mechanism includes: instruction reception confirmation and execution result confirmation, wherein instruction reception confirmation includes: after receiving the encrypted instruction, the on-board gateway immediately sends an instruction reception confirmation package to the remote terminal; if the remote terminal does not receive the instruction reception confirmation package within the first preset time period, the instruction retransmission is triggered; execution result confirmation includes: after the target ECU executes the instruction, an execution result message is generated and returned to the gateway via the CAN bus; the gateway transmits the result message back to the remote terminal through the MQTT protocol, and the remote terminal sends an execution result confirmation package after verification to complete the closed loop; if the execution result confirmation package does not reach the gateway within the first preset time period, the instruction execution failure is marked and an error log is recorded.

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