A vehicle braking distance testing method and device, vehicle and storage medium

Abstract

The application discloses a kind of vehicle brake distance test method, device, vehicle and storage medium, TBOX and the differential positioning terminal of pluggable are deployed on vehicle, method includes: through TBOX real-time acquisition vehicle's whole vehicle signal, when detecting that vehicle satisfies brake distance test condition according to whole vehicle signal, current positioning data of differential positioning terminal is collected as test starting point position data;When detecting that vehicle stops, current positioning data of differential positioning terminal is collected as test end position data, according to test end position data and test starting point position data, determine the brake distance test result corresponding to vehicle;Vehicle corresponding brake distance test result is uploaded to cloud management platform.The technical scheme of the embodiment of the application can reduce the hardware cost consumed in the test process and the complexity of the test process, realize multi-vehicle parallel test, improve the test efficiency of vehicle and the accuracy of test result.

Description

Technical Field

[0001] This invention relates to the field of vehicle networking technology, and in particular to a method, apparatus, vehicle, and storage medium for testing vehicle braking distance. Background Technology

[0002] Currently, conducting braking distance tests on engineering vehicles helps vehicle R&D personnel to promptly identify braking faults, which is of great importance for the safe operation of vehicles. Figure 1 This is an architecture diagram applicable to vehicle braking distance testing in existing technologies, such as... Figure 1 As shown, the typical approach involves installing dedicated brake sensors (such as pressure sensors or stroke sensors) or speed measuring devices on the vehicle under test. Simultaneously, a Real-Time Kinematic (RTK) device is fixedly integrated inside the vehicle. This RTK device relies on Networked Transport of RTCM via Internet Protocol (NTRIP) or point-to-point radio to achieve differential data transmission. The specific testing process is as follows: brake action signals are collected using the installed dedicated sensors, vehicle speed is obtained using the speed measuring device, and then the test procedure is triggered manually based on the signal collection results. Finally, the RTK positioning data and brake signals are transmitted to a dedicated industrial control computer or host computer, where a cloud server calculates the braking distance.

[0003] Existing testing methods have the following drawbacks: The hardware cost of adding extra sensors to vehicles is high, the installation process is cumbersome, and the disassembly and assembly process can easily damage the vehicle's original structure; RTK equipment is a fixed, integrated design, which cannot be reused among multiple test vehicles, requiring repeated investment of hardware equipment for multi-vehicle testing, resulting in resource waste; the testing process relies on manual triggering, and the delay in manual operation can easily lead to brake start-up latch-up deviation, affecting the accuracy of test results, and the overall testing process is time-consuming and inefficient; RTK equipment mostly relies on public network NTRIP differential services, where the public network signal is weak and latency is high in closed testing areas, easily leading to RTK positioning degradation, and point-to-point radios only support single-terminal communication, which cannot meet the needs of multi-vehicle parallel testing. Summary of the Invention

[0004] This invention provides a method, device, vehicle, and storage medium for testing vehicle braking distance, which can significantly reduce the hardware cost and complexity of the testing process, enable parallel testing of multiple vehicles, and improve the testing efficiency and accuracy of test results.

[0005] According to one aspect of the present invention, a method for testing vehicle braking distance is provided, wherein the vehicle is equipped with an onboard telematics box (TBOX) and a pluggable differential positioning terminal, the method being executed by the TBOX and comprising: The vehicle's whole vehicle signals are collected in real time. When the vehicle signals are used to detect that the vehicle meets the braking distance test conditions, the current positioning data collected by the differential positioning terminal is used as the test starting point position data. When the vehicle stops, the current positioning data collected by the differential positioning terminal is used as the test endpoint position data, and the braking distance test result corresponding to the vehicle is determined based on the test endpoint position data and the test start point position data. The braking distance test results corresponding to the vehicle are uploaded to the cloud management platform for storage and display.

[0006] Optionally, the differential positioning terminal acquires differential data based on a pre-built dedicated differential link and locates the vehicle based on the differential data; The dedicated differential link is constructed based on a network of wireless devices and relay terminals; the relay terminal network is constructed based on a navigation satellite system base station with forced alignment, and relay terminals connected to the base station. The relay terminal converts the differential data of the base station into a local area network distribution format by running a forwarding service, so that the differential positioning terminal can read the differential data.

[0007] Optionally, detecting that the vehicle meets the braking distance test conditions based on the vehicle signals includes: Based on the brake switch signal and the instrument panel speed signal, when it is detected that the brake pedal of the vehicle is pressed and the vehicle speed reaches a preset threshold, it is determined that the vehicle meets the braking distance test conditions.

[0008] Optionally, while using the current positioning data collected by the differential positioning terminal as the test starting point position data, it also includes using the current speed of the vehicle as the initial braking speed. Based on the test endpoint location data and the test start point location data, the braking distance test result corresponding to the vehicle is determined, including: Based on the test endpoint position data and the test start point position data, determine the spherical straight-line distance between the test endpoint and the test start point, and use the spherical straight-line distance as the braking distance; Based on the braking distance, initial braking speed, test endpoint position data, test start point position data, and braking duration, the braking distance test result corresponding to the vehicle is generated.

[0009] Optionally, real-time acquisition of vehicle signals, and when the vehicle is detected to meet the braking distance test conditions based on the vehicle signals, the current positioning data acquired by the differential positioning terminal is used as the test starting point position data, including: Vehicle signals are collected in real time via the first Controller Area Network (CAN) channel or the second CAN channel. When the vehicle signal detects that the vehicle meets the braking distance test conditions, the current positioning data collected by the differential positioning terminal is read through the third CAN channel, and the current positioning data is used as the test starting point position data.

[0010] Optionally, the TBOX pre-builds a circular first-in-first-out buffer in local memory; The vehicle's overall signals are acquired in real time via the first or second CAN channel; when the vehicle signals indicate that the vehicle meets the braking distance test conditions, the current positioning data acquired by the differential positioning terminal is read via the third CAN channel, including: The vehicle signals are collected within the target time period before the current moment through the first CAN channel or the second CAN channel, and the vehicle signals are stored in the annular first-in-first-out buffer. The positioning data collected by the differential positioning terminal within the target time period before the current moment is read through the third CAN channel, and the positioning data is stored in the circular first-in-first-out buffer.

[0011] Optionally, before acquiring the vehicle's overall signals in real time via the first CAN channel or the second CAN channel, the following steps are also included: After the TBOX is powered on, the data stream of the third CAN channel is continuously monitored. When the third CAN channel receives a valid message uploaded by the differential positioning terminal, the differential positioning status field in the valid message is verified. If the differential positioning status field is successfully verified, the vehicle is determined to meet the automatic testing conditions.

[0012] Optionally, when the vehicle signal detects that the vehicle meets the braking distance test conditions, the current positioning data collected by the differential positioning terminal is used as the test starting point position data, including: When the brake pedal of the vehicle is detected to be pressed and the vehicle speed reaches a preset threshold, an evaluation time window is constructed with the current moment as the center and a preset duration threshold as the sliding window. Within the evaluation time window, multiple sets of positioning data collected by the differential positioning terminal are acquired, the weight value corresponding to each set of positioning data is determined, and the optimal positioning data is selected as the test starting point location data based on the weight value.

[0013] Optionally, determine the weight value corresponding to each set of location data, including: Determine the physical score, message score, and quality score corresponding to each set of location data; According to the preset weight ratio, the physical score, message score and quality score corresponding to each group of positioning data are weighted and summed to obtain the weight value corresponding to each group of positioning data.

[0014] Optionally, determine the physical score corresponding to each set of location data, including: For each pair of adjacent positioning data in all positioning data, perform differential calculation. Based on the differential calculation results and time intervals, calculate the rate of change of position corresponding to each pair of positioning data. Determine the difference between the position change rate corresponding to each set of positioning data and the instrument vehicle speed signal, and use the difference as the slip rate deviation corresponding to each set of positioning data; Based on the slip rate deviation corresponding to each set of positioning data and the preset physical tolerance threshold, the physical score corresponding to each set of positioning data is determined.

[0015] Optionally, when the vehicle stops, the current positioning data collected by the differential positioning terminal is used as the test endpoint location data, including: When the vehicle's speed is detected to be zero, a standard time window is initiated starting from the current moment; Within the standard time window, the position change rate of the positioning data collected by the differential positioning terminal is monitored at a preset frequency. When the position change rate is continuously less than a preset threshold, the vehicle is determined to stop. An evaluation time window is constructed with the vehicle's stopping time as the center and a preset duration threshold as the sliding window; Within the evaluation time window, multiple sets of positioning data collected by the differential positioning terminal are acquired, the weight value corresponding to each set of positioning data is determined, and the optimal positioning data is selected as the test endpoint location data based on the weight value.

[0016] Optionally, the method further includes: If an anomaly is detected in the differential positioning status field during the braking distance test of the vehicle, the determined braking distance test result will be marked as an abnormal state. The braking distance test results after marking the abnormality are uploaded to the cloud management platform, and the warning sensors in the vehicle are triggered to generate a warning signal.

[0017] According to another aspect of the present invention, a testing apparatus for vehicle braking distance is provided, wherein a TBOX and a pluggable differential positioning terminal are deployed on the vehicle, the apparatus being configured in the TBOX and comprising: The test start point positioning module is used to collect the vehicle's whole vehicle signals in real time. When the vehicle signals detect that the vehicle meets the braking distance test conditions, the current positioning data collected by the differential positioning terminal is used as the test start point position data. The test endpoint positioning module is used to use the current positioning data collected by the differential positioning terminal as the test endpoint position data when the vehicle stops, and to determine the braking distance test result corresponding to the vehicle based on the test endpoint position data and the test start point position data. The test result upload module is used to upload the braking distance test results corresponding to the vehicle to the cloud management platform, so that the braking distance test results can be stored and displayed through the cloud management platform.

[0018] According to another aspect of the present invention, a vehicle is provided, the vehicle including a TBOX and a pluggable differential positioning terminal; the TBOX includes: At least one processor; and a memory communicatively connected to said at least one processor; The memory stores a computer program that can be executed by the at least one processor, which enables the at least one processor to perform the vehicle braking distance testing method according to any embodiment of the present invention.

[0019] According to another aspect of the present invention, a computer-readable storage medium is provided, the computer-readable storage medium storing computer instructions for causing a processor to execute and implement the vehicle braking distance testing method according to any embodiment of the present invention.

[0020] The technical solution provided by this invention uses a TBOX to collect vehicle signals in real time. When the vehicle signals indicate that the vehicle meets the braking distance test conditions, the current positioning data collected by the differential positioning terminal is used as the test start point position data. When the vehicle stops, the current positioning data collected by the differential positioning terminal is used as the test end point position data. Based on the test end point position data and the test start point position data, the braking distance test result corresponding to the vehicle is determined. The braking distance test result corresponding to the vehicle is then uploaded to a cloud management platform. This technical means of storing and displaying the braking distance test results through the cloud management platform can significantly reduce the hardware cost and complexity of the testing process, enable parallel testing of multiple vehicles, and improve the testing efficiency and accuracy of the test results.

[0021] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 A diagram illustrating the architecture applicable to vehicle braking distance testing in existing technologies; Figure 2 This is a flowchart of a vehicle braking distance testing method according to Embodiment 1 of the present invention; Figure 3 This is an architecture diagram applicable to a vehicle braking distance testing method provided by an embodiment of the present invention; Figure 4 This is a flowchart of another vehicle braking distance testing method provided in Embodiment 2 of the present invention; Figure 5 This is a flowchart of another vehicle braking distance testing method provided in Embodiment 3 of the present invention; Figure 6 This is a schematic diagram of the structure of a vehicle braking distance testing device according to Embodiment 4 of the present invention; Figure 7 This is a schematic diagram of the vehicle structure for implementing the vehicle braking distance testing method of Embodiment 5 of the present invention; Figure 8 This is a schematic diagram of the structure of a TBOX that implements the vehicle braking distance testing method of Embodiment 5 of the present invention. Detailed Implementation

[0024] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0025] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0026] Example 1 Figure 2 This is a flowchart of a vehicle braking distance testing method provided in Embodiment 1 of the present invention. This embodiment is applicable to testing the braking distance of engineering vehicles. The method can be executed by a vehicle braking distance testing device, which can be implemented in hardware and / or software and configured in the vehicle's TBOX. The vehicle also includes a pluggable differential positioning terminal. Figure 2 As shown, the method includes: Step 110: Collect the vehicle's whole vehicle signal in real time. When the vehicle meets the braking distance test conditions based on the whole vehicle signal, use the current positioning data collected by the differential positioning terminal as the test starting point position data.

[0027] In this embodiment, the TBOX is the original remote information processing terminal in the vehicle under test, running the ThreadX real-time operating system and having multiple CAN channels. The differential positioning terminal (i.e., RTK slave) is a standardized plug-and-play device that can be used across multiple test vehicles.

[0028] In this step, specifically, the TBOX can use the first CAN channel and the second CAN channel to collect the vehicle's Body Control Module (BCM) signal and Engine Management System (EMS) signal in real time. When the vehicle's brake pedal is triggered or the vehicle triggers a brake test request based on the BCM signal and EMS signal, the current positioning data collected by the differential positioning terminal can be used as the test starting point position data.

[0029] In this embodiment, the differential positioning terminal acquires differential data based on a pre-built dedicated differential link and locates the vehicle based on the differential data.

[0030] The dedicated differential link is constructed based on a network of wireless devices and relay terminals; the relay terminal network is constructed based on a navigation satellite system base station with forced alignment and relay terminals connected to the base station; the relay terminal converts the differential data of the base station into a local area network distribution format by running a forwarding service, so that the differential positioning terminal can read the differential data.

[0031] In one specific embodiment Figure 3 This can be a diagram illustrating the architecture applicable to the vehicle braking distance testing method in this embodiment, such as... Figure 3 As shown, before step 110, a Global Navigation Satellite System (GNSS) base station can be pre-set in an open area of ​​the closed test site and forced to center. The base station is connected to the relay terminal via a serial port or network cable. The relay terminal converts the differential data of the base station into a local area network-distributable format by running a forwarding service. Then, the industrial wireless device (Wireless Access Point, AP) is started. The wireless AP is networked with the relay terminal through the core switch, thereby forming a dedicated differential link based on the NTRIP protocol in the closed site, so that the differential positioning terminal can obtain differential data according to the dedicated differential link.

[0032] In this embodiment, after constructing a dedicated differential link in the above manner, a pluggable differential positioning terminal can be connected to the vehicle under test, and the CAN differential signal line of the differential positioning terminal can be connected to the third CAN channel of the TBOX, thereby enabling the differential positioning terminal to complete the initial configuration.

[0033] The advantages of this setup are twofold: firstly, by establishing a dedicated differential link within a closed testing area, reliance on the public network can be reduced, avoiding deviations in test results due to public network signal delays; secondly, by configuring pluggable differential positioning terminals, the reusability of the differential positioning terminals can be improved, enabling parallel testing of multiple vehicles and enhancing vehicle testing efficiency.

[0034] Step 120: When the vehicle stops, the current positioning data collected by the differential positioning terminal is used as the test endpoint position data, and the braking distance test result corresponding to the vehicle is determined based on the test endpoint position data and the test start point position data.

[0035] In this step, optionally, TBOX can calculate the distance between the test endpoint and the test start point based on the test endpoint location data and the test start point location data, and use this distance as the vehicle's braking distance.

[0036] Step 130: Upload the braking distance test results corresponding to the vehicle to the cloud management platform so that the braking distance test results can be stored and displayed through the cloud management platform.

[0037] In this embodiment, the vehicle's original TBOX is reused to collect vehicle signals and test the vehicle's braking distance. There is no need to install additional sensors on the vehicle, which can reduce the hardware cost of vehicle braking distance testing and avoid damage to the vehicle's original structure caused by adding additional sensors. Secondly, the test process is automatically triggered by the TBOX, which can avoid the impact of delays caused by manual operation on the accuracy of test results, thereby improving the vehicle testing efficiency and the accuracy of test results.

[0038] The technical solution provided by this invention uses a TBOX to collect vehicle signals in real time. When the vehicle signals indicate that the vehicle meets the braking distance test conditions, the current positioning data collected by the differential positioning terminal is used as the test start point position data. When the vehicle stops, the current positioning data collected by the differential positioning terminal is used as the test end point position data. Based on the test end point position data and the test start point position data, the braking distance test result corresponding to the vehicle is determined. The braking distance test result corresponding to the vehicle is then uploaded to a cloud management platform. This technical means of storing and displaying the braking distance test results through the cloud management platform can significantly reduce the hardware cost and complexity of the testing process, enable parallel testing of multiple vehicles, and improve the testing efficiency and accuracy of the test results.

[0039] Example 2 Figure 4 A flowchart of another vehicle braking distance testing method provided in Embodiment 2 of the present invention is shown below. Figure 4 As shown, the method includes: Step 210: After the TBOX is powered on, continuously monitor the data stream of the third CAN channel. When the third CAN channel receives a valid message uploaded by the differential positioning terminal, verify the differential positioning status field in the valid message. If the differential positioning status field is successfully verified, it is determined that the vehicle meets the automatic test conditions.

[0040] In this embodiment, before testing the vehicle's braking distance, the Message Queuing Telemetry Transport (MQTT) connection between the TBOX and the cloud management platform can be initiated after the TBOX is powered on, and the data flow of the TBOX's third CAN channel can be continuously monitored within a preset time.

[0041] If the third CAN channel receives a valid message from the differential positioning terminal within a preset time period, it can be determined that the differential positioning terminal is successfully connected to the TBOX. It can also verify whether the differential positioning status field RTK_Status in the valid message is a preset value (e.g., RTK_Status=5). If so, it can be determined that the differential positioning status field has been successfully verified, and an indication signal can be sent to the vehicle controller so that the vehicle controller can control the "system ready" indicator light to illuminate.

[0042] If the third CAN channel does not receive a valid message from the differential positioning terminal within a preset time period, the TBOX can report a "device offline" alarm signal to the cloud management platform via MQTT connection, while keeping the TBOX in standby mode.

[0043] The advantage of this setup is that it allows TBOX to automatically determine the working status of the differential positioning terminal, reducing manual intervention during the testing process.

[0044] Step 220: Collect vehicle signals in real time through the first CAN channel or the second CAN channel. Based on the brake switch signal and the instrument speed signal, when the vehicle's brake pedal is pressed and the vehicle speed reaches a preset threshold, determine that the vehicle meets the braking distance test conditions.

[0045] In this embodiment, optionally, if the brake switch signal includes the information "Brake_Switch=ON", it can be determined that the vehicle's brake pedal is depressed. Simultaneously, if the vehicle speed is greater than or equal to 40 km / h, it is determined that the vehicle meets the braking distance test conditions. Specifically, the preset threshold can be adjusted according to actual conditions; this embodiment does not impose any limitations on this.

[0046] Step 230: Read the current positioning data collected by the differential positioning terminal through the third CAN channel, use the current positioning data as the test starting point position data, and use the vehicle's current speed as the initial braking speed.

[0047] In this embodiment, after determining that the vehicle meets the braking distance test conditions through the above steps, the current latitude and longitude coordinate data uploaded by the differential positioning terminal can be immediately latched and used as the test starting point position data. At the same time, the current instrument speed can be latched as the initial braking speed, and a timer can be started to count the duration of vehicle braking.

[0048] In one specific embodiment, after determining that the vehicle meets the braking distance test conditions, the TBOX can read the positioning data collected by the differential positioning terminal through the third CAN channel at a preset frequency. The positioning data is centimeter-level positioning data based on differential local area network positioning within a closed area. The preset frequency can be 10Hz, and the specific value can be adjusted according to actual conditions; this embodiment does not impose any limitations on this.

[0049] In one embodiment of this example, the TBOX pre-constructs a circular First-In-First-Out (FIFO) buffer in its local memory. Vehicle signals are acquired in real time via a first or second CAN channel. When the vehicle signals indicate that the vehicle meets the braking distance test conditions, the current positioning data acquired by the differential positioning terminal is read via a third CAN channel. This includes: acquiring vehicle signals within a target time period prior to the current moment via the first or second CAN channel and storing the vehicle signals in the circular FIFO buffer; and reading positioning data acquired by the differential positioning terminal within the target time period prior to the current moment via the third CAN channel and storing the positioning data in the circular FIFO buffer.

[0050] Specifically, the ring FIFO is used to continuously receive vehicle signals from the first CAN channel and the second CAN channel (with a collection period of 10ms-50ms), as well as positioning data from the third CAN channel (with a collection period of 100ms). After receiving each frame of CAN data and positioning data, the edge computing module in the TBOX can annotate the data with a local high-precision timestamp and complete the timestamp alignment in memory, thereby constructing a synchronization data packet.

[0051] The advantage of this setup is that it allows braking triggering and data latching operations to be completed locally on the TBOX. By isolating the sending, receiving, and parsing tasks of multiple CAN messages with different cycles through a circular buffer, it can avoid frame loss caused by message concurrency. At the same time, due to the low-latency read and write characteristics of high-speed memory, it can provide continuous and complete raw data support for multi-source data timing alignment and edge fusion computing.

[0052] Step 240: When the vehicle stops, the current positioning data collected by the differential positioning terminal is used as the test endpoint position data. Based on the test endpoint position data and the test start point position data, the spherical straight-line distance between the test endpoint and the test start point is determined, and the spherical straight-line distance is used as the braking distance.

[0053] In this embodiment, when the TBOX detects that the vehicle speed has dropped to 0 km / h (i.e., the vehicle has come to a complete stop) via the vehicle signal, it can determine that the test process has ended and immediately latch the current latitude and longitude coordinate data uploaded by the differential positioning terminal, using this latitude and longitude coordinate data as the test endpoint location data. After obtaining the test endpoint location data, the TBOX can calculate the spherical straight-line distance between the test endpoint and the test starting point using the Haversine semi-sine function, and use this spherical straight-line distance as the braking distance.

[0054] The advantage of this setup is that, compared to existing technologies that rely on industrial control computers or cloud servers to calculate braking distances, the vehicle's original TBOX can automatically calculate the braking distance, reducing data latency when the vehicle interacts with the cloud server and improving the reliability of test results.

[0055] In one specific embodiment, the angle between the centers of the spheres of the two points can be calculated by combining the Haversine semi-versus function with the difference in latitude and longitude between the test endpoint and the test starting point. Then, the angle between the centers of the spheres is multiplied by the Earth's radius to obtain the spherical straight-line distance between the two points on the Earth's surface.

[0056] Step 250: Generate the braking distance test results for the vehicle based on the braking distance, initial braking speed, test endpoint position data, test start point position data, and braking duration.

[0057] In one specific embodiment, braking distance, initial braking speed, test endpoint position data, test start point position data, braking duration, differential positioning terminal ID, and TBOX ID can be encapsulated into a JSON format data packet.

[0058] Step 260: Upload the corresponding braking distance test results of the vehicle to the cloud management platform so that the braking distance test results can be stored and displayed through the cloud management platform.

[0059] In this step, the data packet encapsulated in step 250 can be uploaded to the cloud management platform via the MQTT protocol through the communication module built into TBOX. The cloud management platform can parse the data packet according to the preset delimiter or identifier to obtain data such as the vehicle's braking distance, initial braking speed, test endpoint position data, test start point position data, and braking duration, and display the above data through a visual interface.

[0060] In one embodiment of this invention, after TBOX uploads the braking distance test results to the cloud management platform, it can reset the operating state to the test state to conduct the next round of braking distance tests on the vehicle. If the vehicle tester needs to test another vehicle, they only need to unplug the differential positioning terminal from the current vehicle and insert it into the other vehicle, then repeat steps 210-260 above on the other vehicle. This enables the cross-vehicle reuse of the differential positioning terminal, avoiding the waste of resources caused by repeatedly investing in hardware equipment when testing multiple vehicles.

[0061] In this embodiment, the method further includes: when an abnormality is detected in the differential positioning status field during the braking distance test of the vehicle, marking the determined braking distance test result as an abnormal state; uploading the marked abnormal braking distance test result to the cloud management platform, and simultaneously triggering the warning sensor in the vehicle to generate a warning signal.

[0062] In one specific implementation, the TBOX can monitor the working status of the differential positioning terminal in real time throughout the entire testing process. If an anomaly is detected in the differential positioning status field (e.g., RTK_Status=4), the current testing process can continue without interruption. The braking distance between the test endpoint and the test start point can be calculated, and then the calculated braking distance, initial braking speed, test endpoint position data, test start point position data, braking duration, differential positioning terminal ID, and TBOX ID can be encapsulated into a JSON format data packet. This data packet is marked with "WARNING," and the reason for the anomaly (e.g., "RTK signal interruption") is written in the packet's remarks field. Upon receiving the anomaly-marked data packet, the cloud management platform can differentiate the data packet to prevent erroneous data from misleading analysis. Simultaneously, the TBOX triggers a local audible and visual warning to remind testers to handle the anomaly as soon as possible.

[0063] The advantage of this setup is that, in existing testing processes, if anomalies such as RTK signal loss or positioning status degradation occur, the test is usually directly interrupted, lacking a continuous calculation and anomaly marking mechanism. This not only affects the test progress but also easily leads to invalid data. In contrast, this embodiment provides a complete anomaly handling mechanism. That is, if an RTK signal anomaly occurs during the test, the calculation is not interrupted, but the data is marked as an anomaly. This avoids the progress delay caused by test interruption and can distinguish between valid test results and abnormal test results through differentiated identification, ensuring the reliability and traceability of test results.

[0064] The technical solution provided by this invention continuously monitors the data stream of the third CAN channel after the TBOX is powered on, verifies the differential positioning status field in the valid message uploaded by the differential positioning terminal, and determines that the vehicle meets the automatic test conditions. Then, it collects the vehicle's whole-vehicle signals in real time through the first or second CAN channel. When it detects that the vehicle's brake pedal is depressed and the vehicle speed reaches a preset threshold, it determines that the vehicle meets the braking distance test conditions. It reads the test start-point position data through the third CAN channel and the test end-point position data when the vehicle stops. Based on the braking distance, initial braking speed, test end-point position data, test start-point position data, and braking duration, it generates the corresponding braking distance test result for the vehicle and uploads the corresponding braking distance test result to the cloud management platform. This cloud management platform stores and displays the braking distance test results, significantly reducing the hardware cost and complexity of the testing process, enabling parallel testing of multiple vehicles, and improving the testing efficiency and accuracy of the test results.

[0065] Example 3 Figure 5 A flowchart of another vehicle braking distance testing method provided in Embodiment 3 of the present invention is shown below. Figure 5 As shown, the method includes: Step 310: Collect vehicle signals in real time. Based on the brake switch signal and the instrument speed signal, when the brake pedal of the vehicle is detected to be pressed and the vehicle speed reaches a preset threshold, construct an evaluation time window with the current moment as the center and a preset duration threshold as the sliding window.

[0066] Step 320: Acquire multiple sets of positioning data collected by the differential positioning terminal within the evaluation time window, determine the weight value corresponding to each set of positioning data, and select the optimal positioning data as the test starting point location data according to the weight value.

[0067] In practical applications, due to the periodic transmission interval of CAN signals and the asynchronous nature of the positioning data collected by the differential positioning terminal, directly capturing a single frame of positioning data at the instant the brake pedal is depressed and the vehicle speed reaches a preset threshold will cause timeline misalignment. To address this, this embodiment provides a sliding window latching mechanism based on a time window. When the edge computing module of the TBOX determines that the brake pedal has been depressed and the vehicle speed is greater than or equal to the preset threshold, it does not immediately capture the current positioning data of the differential positioning terminal. Instead, it extracts sliding windows with a preset duration threshold (0.2s) forward and backward from the local memory, centered on the current trigger time T0, and constructs an evaluation time window with a total duration of 0.4s.

[0068] In this step, the edge computing module of TBOX can perform a confidence assessment on each set of location data within the evaluation time window, determine the weight value Wi corresponding to each set of location data based on the evaluation results, and then select the set of location data with the largest weight value Wi as the latched test starting point location data.

[0069] The advantage of this setting is that it ensures that when a data change occurs at the current trigger time T0, TBOX can still backtrack to the most accurate positioning data in local memory for latching, thereby improving the reliability of subsequent braking distance test results.

[0070] In one embodiment of this example, determining the weight value corresponding to each set of positioning data includes: determining the physical score, message score, and quality score corresponding to each set of positioning data; and weighting and summing the physical score, message score, and quality score corresponding to each set of positioning data according to a preset weight ratio to obtain the weight value corresponding to each set of positioning data.

[0071] Specifically, the TBOX edge computing module can pre-build a multi-source data credibility assessment model to perform credibility assessment on each set of location data within the aforementioned time window. In this model, each set of location data corresponds to a weight value. It can be calculated using the following formula: , in, Score the physical consistency of the i-th set of location data. This is a message score used to assess the integrity of location data based on cyclic integrity and cyclic redundancy check (CRC). To assess the quality of positioning data based on carrier-to-noise ratio, satellite data, and differential positioning status fields. , , The preset weighting coefficients, Optionally, to allow physical cross-validation to play a dominant role, you can set... Value greater than and .

[0072] In one specific embodiment, determining the physical score corresponding to each set of positioning data includes: performing differential calculation on every two adjacent sets of positioning data in all positioning data; calculating the position change rate corresponding to each set of positioning data based on the differential calculation results and time intervals; determining the difference between the position change rate corresponding to each set of positioning data and the instrument vehicle speed signal, and using the difference as the slip rate deviation corresponding to each set of positioning data; and determining the physical score corresponding to each set of positioning data based on the slip rate deviation corresponding to each set of positioning data and a preset physical tolerance threshold.

[0073] In this embodiment, physical consistency scoring The calculation is performed locally by the TBOX edge computing module based on vehicle kinematics. TBOX can perform differential calculations on the latitude and longitude coordinates of adjacent positioning data frames, and then calculate the instantaneous movement speed of the positioning data frames as the rate of position change based on the inter-frame time interval. Then The instrument speed signal at the same timestamp The difference is used to obtain the slip ratio deviation. , .if If the value is greater than or equal to the preset physical tolerance threshold, the positioning data is determined to have inertial slip transient distortion or positioning jump, and therefore its physical consistency score is reduced. Significantly reduced.

[0074] The advantage of this setup is that it can effectively eliminate pseudo-precise positioning data and isolate transient data noise, thereby improving the accuracy of subsequent braking distance test results.

[0075] Step 330: When the vehicle speed is detected to be zero, a standard time window is started from the current time. Within the standard time window, the position change rate of the positioning data collected by the differential positioning terminal is monitored at a preset frequency. When the position change rate is continuously less than a preset threshold, the vehicle is determined to stop.

[0076] In practical applications, during emergency braking, the intervention of the Anti-lock Braking System (ABS) can cause the wheels to lock up, but the vehicle body still has inertial slippage. If only the instrument speedometer reading of zero is used as the endpoint criterion, latching will be premature. To address this, this embodiment provides a dual-criteria delayed latching mechanism. First, the instrument speedometer signal is monitored. When the speed is zero, latching is not performed. Instead, a standard time window of a preset duration (0.5s) is initiated locally. Within this standard time window, the position change rate of the positioning data collected by the differential positioning terminal is monitored at a preset frequency (10Hz). .

[0077] If the rate of change of position approaches zero for multiple consecutive frames (e.g., 3 consecutive frames) (e.g.) If the distance is less than 0.05m, it can be determined that the vehicle body's inertial slippage has been eliminated and the vehicle has reached a stationary state.

[0078] Step 340: Construct an evaluation time window centered on the stopping time of the vehicle and using a preset duration threshold as a sliding window. Within the evaluation time window, acquire multiple sets of positioning data collected by the differential positioning terminal, determine the weight value corresponding to each set of positioning data, and select the optimal positioning data as the test endpoint location data based on the weight value.

[0079] In this step, optionally, the weight value corresponding to each set of positioning data can be determined in the same way as in step 320, and then the set of positioning data with the largest weight value can be selected as the latched test endpoint location data.

[0080] The advantage of this setup is that the dual-criteria delay latching mechanism can accurately compensate for the residual slip distance under ABS conditions, solve the measurement deviation caused by the distortion of braking transient data, and realize high-precision automated testing under a low-cost hardware architecture.

[0081] Step 350: Determine the braking distance test result corresponding to the vehicle based on the test endpoint position data and the test start point position data.

[0082] Step 360: Upload the braking distance test results corresponding to the vehicle to the cloud management platform so that the braking distance test results can be stored and displayed through the cloud management platform.

[0083] The technical solution provided in this invention collects vehicle signals in real time. Based on the brake switch signal and the instrument speed signal, when the brake pedal is detected to be depressed and the vehicle speed reaches a preset threshold, an evaluation time window is constructed with the current moment as the center and a preset duration threshold as the sliding window. Within the evaluation time window, multiple sets of positioning data collected by the differential positioning terminal are acquired, and the weight value corresponding to each set of positioning data is determined. The optimal positioning data is selected as the test starting point position data according to the weight value. When the vehicle speed is detected to be zero, a standard time window is started with the current moment as the starting point. Within the standard time window, the position change rate of the positioning data collected by the differential positioning terminal is monitored at a preset frequency. When the position change rate is continuously less than a preset threshold, the vehicle is determined to have stopped. The system constructs an evaluation time window centered on the vehicle's stopping moment and using a preset time threshold as a sliding window. Within this window, multiple sets of positioning data collected by the differential positioning terminal are acquired. The weight value corresponding to each set of positioning data is determined, and the optimal positioning data is selected as the test endpoint location data based on the weight value. The braking distance test result for the vehicle is determined based on the test endpoint location data and the test start point location data. The braking distance test result for the vehicle is then uploaded to a cloud management platform. This technology, which stores and displays the braking distance test results through a cloud management platform, can significantly reduce the hardware costs and complexity of the testing process, enable parallel testing of multiple vehicles, and improve the testing efficiency and accuracy of the test results.

[0084] Example 4 Figure 6 This is a schematic diagram of the structure of a vehicle braking distance testing device provided in Embodiment 4 of the present invention, as shown below. Figure 6 As shown, the device includes: a test start point positioning module 410, a test end point positioning module 420, and a test result uploading module 430.

[0085] The test starting point positioning module 410 is used to collect the vehicle's whole vehicle signals in real time. When the vehicle signals detect that the vehicle meets the braking distance test conditions, the current positioning data collected by the differential positioning terminal is used as the test starting point position data. The test endpoint positioning module 420 is used to use the current positioning data collected by the differential positioning terminal as the test endpoint position data when the vehicle stops, and to determine the braking distance test result corresponding to the vehicle based on the test endpoint position data and the test start point position data. The test result upload module 430 is used to upload the braking distance test results corresponding to the vehicle to the cloud management platform, so that the braking distance test results can be stored and displayed through the cloud management platform.

[0086] The technical solution provided by this invention uses a TBOX to collect vehicle signals in real time. When the vehicle signals indicate that the vehicle meets the braking distance test conditions, the current positioning data collected by the differential positioning terminal is used as the test start point position data. When the vehicle stops, the current positioning data collected by the differential positioning terminal is used as the test end point position data. Based on the test end point position data and the test start point position data, the braking distance test result corresponding to the vehicle is determined. The braking distance test result corresponding to the vehicle is then uploaded to a cloud management platform. This technical means of storing and displaying the braking distance test results through the cloud management platform can significantly reduce the hardware cost and complexity of the testing process, enable parallel testing of multiple vehicles, and improve the testing efficiency and accuracy of the test results.

[0087] Based on the above embodiments, the differential positioning terminal acquires differential data based on a pre-built dedicated differential link, and locates the vehicle according to the differential data; The dedicated differential link is constructed based on a network of wireless devices and relay terminals; the relay terminal network is constructed based on a navigation satellite system base station with forced alignment, and relay terminals connected to the base station. The relay terminal converts the differential data of the base station into a local area network distribution format by running a forwarding service, so that the differential positioning terminal can read the differential data.

[0088] The test starting point positioning module 410 includes: The signal detection unit is used to determine that the vehicle meets the braking distance test conditions when the brake pedal of the vehicle is pressed and the vehicle speed reaches a preset threshold, based on the brake switch signal and the instrument vehicle speed signal. The initial speed determination unit is used to take the current positioning data collected by the differential positioning terminal as the test starting point position data and the current speed of the vehicle as the braking initial speed. The CAN channel acquisition unit is used to acquire the vehicle's whole vehicle signals in real time through the first CAN channel or the second CAN channel; when the vehicle signals detect that the vehicle meets the braking distance test conditions, the unit reads the current positioning data acquired by the differential positioning terminal through the third CAN channel and uses the current positioning data as the test starting point position data. The buffer storage unit is used to collect the vehicle's whole vehicle signal within the target time period before the current time through the first CAN channel or the second CAN channel, and store the whole vehicle signal into the circular first-in-first-out buffer; and to read the positioning data collected by the differential positioning terminal within the target time period before the current time through the third CAN channel, and store the positioning data into the circular first-in-first-out buffer; the TBOX has a circular first-in-first-out buffer pre-built in its local memory; The first data evaluation unit is used to detect when the brake pedal of the vehicle is pressed and the vehicle speed reaches a preset threshold, and construct an evaluation time window with the current time as the center and a preset duration threshold as a sliding window; within the evaluation time window, acquire multiple sets of positioning data collected by the differential positioning terminal, determine the weight value corresponding to each set of positioning data, and select the optimal positioning data as the test starting point position data according to the weight value. The weight value determination unit is used to determine the physical score, message score and quality score corresponding to each group of positioning data; according to the preset weight ratio, the physical score, message score and quality score corresponding to each group of positioning data are weighted and summed to obtain the weight value corresponding to each group of positioning data. The physical scoring unit is used to perform differential calculation on every two adjacent sets of positioning data in all positioning data. Based on the differential calculation results and time intervals, it calculates the position change rate corresponding to each set of positioning data; determines the difference between the position change rate corresponding to each set of positioning data and the instrument vehicle speed signal, and uses the difference as the slip rate deviation corresponding to each set of positioning data; and determines the physical score corresponding to each set of positioning data based on the slip rate deviation corresponding to each set of positioning data and the preset physical tolerance threshold.

[0089] The test endpoint positioning module 420 includes: The distance determination unit is used to determine the spherical straight-line distance between the test endpoint and the test start point based on the test endpoint position data and the test start point position data, and to use the spherical straight-line distance as the braking distance; The test result generation unit is used to generate the braking distance test result corresponding to the vehicle based on the braking distance, initial braking speed, test end point position data, test start point position data and braking duration. The second data evaluation unit is used to start a standard time window starting from the current moment when the vehicle speed is detected to be zero; within the standard time window, the position change rate of the positioning data collected by the differential positioning terminal is monitored at a preset frequency; when the position change rate is continuously less than a preset threshold, the vehicle is determined to stop; an evaluation time window is constructed with the stopping time of the vehicle as the center and a preset duration threshold as a sliding window; within the evaluation time window, multiple sets of positioning data collected by the differential positioning terminal are acquired, the weight value corresponding to each set of positioning data is determined, and the optimal positioning data is selected as the test endpoint position data according to the weight value.

[0090] The device further includes: The preprocessing module is used to continuously monitor the data stream of the third CAN channel after the TBOX is powered on. When the third CAN channel receives a valid message uploaded by the differential positioning terminal, it verifies the differential positioning status field in the valid message. If the differential positioning status field is successfully verified, it is determined that the vehicle meets the automatic test conditions. The anomaly handling module is used to mark the determined braking distance test result as an abnormal state when an anomaly is detected in the differential positioning status field during the braking distance test of the vehicle; the marked braking distance test result is uploaded to the cloud management platform, and the warning sensors in the vehicle are triggered to generate a warning signal.

[0091] The above-described apparatus can execute the methods provided in all the foregoing embodiments of the present invention, and has the corresponding functional modules and beneficial effects for executing the above methods. Technical details not described in detail in the embodiments of the present invention can be found in the methods provided in all the foregoing embodiments of the present invention.

[0092] Example 5 Figure 7 A schematic diagram of a vehicle that can be used to implement Embodiment 5 of the present invention is shown, the vehicle including TBOX 10 and a pluggable differential positioning terminal 20.

[0093] Figure 8 A schematic diagram of the structure of TBOX 10, which can be used to implement Embodiment 5 of the present invention, is shown, as follows. Figure 8As shown, the TBOX 10 includes at least one processor 11 and a memory, such as a read-only memory (ROM) or a random access memory (RAM), communicatively connected to the at least one processor 11. The memory stores computer programs executable by the at least one processor. The processor 11 can perform various appropriate actions and processes based on the computer program stored in the read-only memory 12 or loaded from the storage unit 18 into the random access memory 13. The random access memory 13 can also store various programs and data required for the operation of the TBOX 10. The processor 11, the read-only memory 12, and the random access memory 13 are interconnected via a bus 14. Input / output (I / O) interfaces are also connected to the bus 14.

[0094] Multiple components in the TBOX 10 are connected to the input / output interface 15, including: an input unit 16, such as a keyboard, mouse, etc.; an output unit 17, such as various types of displays, speakers, etc.; a storage unit 18, such as a disk, optical disk, etc.; and a communication unit 19, such as a network card, modem, wireless transceiver, etc. The communication unit 19 allows the TBOX 10 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0095] Processor 11 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, digital signal processing (DSP) processors, and any suitable processor, controller, microcontroller, etc. Processor 11 performs the various methods and processes described above, such as the vehicle braking distance testing method.

[0096] In some embodiments, the vehicle braking distance testing method may be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or installed on TBOX 10 via read-only memory 12 and / or communication unit 19. When the computer program is loaded into random access memory 13 and executed by processor 11, one or more steps of the vehicle braking distance testing method described above may be performed. Alternatively, in other embodiments, processor 11 may be configured to perform the vehicle braking distance testing method by any other suitable means (e.g., by means of firmware).

[0097] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-chips (SoCs), complex programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0098] Computer programs used to implement the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the processor, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be performed. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0099] In the context of this invention, a computer-readable storage medium can be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, apparatus, or device. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, RAM, ROM, erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0100] To provide interaction with the user, the systems and technologies described herein can be implemented in a vehicle having: a display device for displaying information to the user (e.g., a cathode ray tube (CRT) or a liquid crystal display (LCD)); and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the vehicle. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0101] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as data servers), or middleware components (e.g., application servers), or frontend components (e.g., user computers with graphical user interfaces or web browsers through which users can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., communication networks). Examples of communication networks include local area networks (LANs), wide area networks (WANs), blockchain networks, and the Internet.

[0102] A computing system can include clients and servers. Clients and servers are generally geographically separated and typically interact via communication networks. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a hosting product within the cloud computing service system. It addresses the shortcomings of traditional physical hosts and Virtual Private Servers (VPS) in terms of management difficulty and weak business scalability.

[0103] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0104] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for testing vehicle braking distance, characterized in that, The vehicle is equipped with an onboard telematics terminal (TBOX) and a pluggable differential positioning terminal. The method is executed by the TBOX and includes: The vehicle's whole vehicle signals are collected in real time. When the vehicle signals are used to detect that the vehicle meets the braking distance test conditions, the current positioning data collected by the differential positioning terminal is used as the test starting point position data. When the vehicle stops, the current positioning data collected by the differential positioning terminal is used as the test endpoint position data, and the braking distance test result corresponding to the vehicle is determined based on the test endpoint position data and the test start point position data. The braking distance test results corresponding to the vehicle are uploaded to the cloud management platform for storage and display.

2. The method according to claim 1, characterized in that, The differential positioning terminal acquires differential data based on a pre-built dedicated differential link and locates the vehicle based on the differential data. The dedicated differential link is constructed based on a network of wireless devices and relay terminals; the relay terminal network is constructed based on a navigation satellite system base station with forced alignment, and relay terminals connected to the base station. The relay terminal converts the differential data of the base station into a local area network distribution format by running a forwarding service, so that the differential positioning terminal can read the differential data.

3. The method according to claim 1, characterized in that, According to the vehicle signal detection, the vehicle meets the braking distance test conditions, including: Based on the brake switch signal and the instrument panel speed signal, when it is detected that the brake pedal of the vehicle is pressed and the vehicle speed reaches a preset threshold, it is determined that the vehicle meets the braking distance test conditions.

4. The method according to claim 1, characterized in that, In addition to using the current positioning data collected by the differential positioning terminal as the test starting point location data, it also includes: Use the vehicle's current speed as the initial braking speed; Based on the test endpoint location data and the test start point location data, the braking distance test result corresponding to the vehicle is determined, including: Based on the test endpoint position data and the test start point position data, determine the spherical straight-line distance between the test endpoint and the test start point, and use the spherical straight-line distance as the braking distance; Based on the braking distance, initial braking speed, test endpoint position data, test start point position data, and braking duration, the braking distance test result corresponding to the vehicle is generated.

5. The method according to claim 1, characterized in that, Real-time acquisition of vehicle signals; when the vehicle meets the braking distance test conditions based on the vehicle signals, the current positioning data acquired by the differential positioning terminal is used as the test starting point position data, including: Vehicle signals are collected in real time via the first controller area network CAN channel or the second CAN channel. When the vehicle signal detects that the vehicle meets the braking distance test conditions, the current positioning data collected by the differential positioning terminal is read through the third CAN channel, and the current positioning data is used as the test starting point position data.

6. The method according to claim 5, characterized in that, The TBOX has a pre-built circular first-in-first-out buffer in local memory; Vehicle signals are collected in real time via the first CAN channel or the second CAN channel. When the vehicle signal detects that the vehicle meets the braking distance test conditions, the current positioning data collected by the differential positioning terminal is read through the third CAN channel, including: The vehicle signals are collected within the target time period before the current moment through the first CAN channel or the second CAN channel, and the vehicle signals are stored in the annular first-in-first-out buffer. The positioning data collected by the differential positioning terminal within the target time period before the current moment is read through the third CAN channel, and the positioning data is stored in the circular first-in-first-out buffer.

7. The method according to claim 5, characterized in that, Before acquiring vehicle signals in real time via the first or second CAN channel, the process also includes: After the TBOX is powered on, the data stream of the third CAN channel is continuously monitored. When the third CAN channel receives a valid message uploaded by the differential positioning terminal, the differential positioning status field in the valid message is verified. If the differential positioning status field is successfully verified, the vehicle is determined to meet the automatic testing conditions.

8. The method according to claim 3, characterized in that, When the vehicle signal detects that the vehicle meets the braking distance test conditions, the current positioning data collected by the differential positioning terminal is used as the test starting point position data, including: When the brake pedal of the vehicle is detected to be pressed and the vehicle speed reaches a preset threshold, an evaluation time window is constructed with the current moment as the center and a preset duration threshold as the sliding window. Within the evaluation time window, multiple sets of positioning data collected by the differential positioning terminal are acquired, the weight value corresponding to each set of positioning data is determined, and the optimal positioning data is selected as the test starting point location data based on the weight value.

9. The method according to claim 8, characterized in that, Determine the weight value corresponding to each set of location data, including: Determine the physical score, message score, and quality score corresponding to each set of location data; According to the preset weight ratio, the physical score, message score and quality score corresponding to each group of positioning data are weighted and summed to obtain the weight value corresponding to each group of positioning data.

10. The method according to claim 9, characterized in that, Determine the physical score corresponding to each set of location data, including: For each pair of adjacent positioning data in all positioning data, perform differential calculation. Based on the differential calculation results and time intervals, calculate the rate of change of position corresponding to each pair of positioning data. Determine the difference between the position change rate corresponding to each set of positioning data and the instrument vehicle speed signal, and use the difference as the slip rate deviation corresponding to each set of positioning data; Based on the slip rate deviation corresponding to each set of positioning data and the preset physical tolerance threshold, the physical score corresponding to each set of positioning data is determined.

11. The method according to claim 1, characterized in that, When the vehicle stops, the current positioning data collected by the differential positioning terminal is used as the test endpoint location data, including: When the vehicle's speed is detected to be zero, a standard time window is initiated starting from the current moment; Within the standard time window, the position change rate of the positioning data collected by the differential positioning terminal is monitored at a preset frequency. When the position change rate is continuously less than a preset threshold, the vehicle is determined to stop. An evaluation time window is constructed with the vehicle's stopping time as the center and a preset duration threshold as the sliding window; Within the evaluation time window, multiple sets of positioning data collected by the differential positioning terminal are acquired, the weight value corresponding to each set of positioning data is determined, and the optimal positioning data is selected as the test endpoint location data based on the weight value.

12. The method according to claim 7, characterized in that, The method further includes: If an anomaly is detected in the differential positioning status field during the braking distance test of the vehicle, the determined braking distance test result will be marked as an abnormal state. The braking distance test results after marking the abnormality are uploaded to the cloud management platform, and the warning sensors in the vehicle are triggered to generate a warning signal.

13. A testing device for vehicle braking distance, characterized in that, The vehicle is equipped with an onboard telematics terminal (TBOX) and a pluggable differential positioning terminal. The device is configured within the TBOX and includes: The test start point positioning module is used to collect the vehicle's whole vehicle signals in real time. When the vehicle signals detect that the vehicle meets the braking distance test conditions, the current positioning data collected by the differential positioning terminal is used as the test start point position data. The test endpoint positioning module is used to use the current positioning data collected by the differential positioning terminal as the test endpoint position data when the vehicle stops, and to determine the braking distance test result corresponding to the vehicle based on the test endpoint position data and the test start point position data. The test result upload module is used to upload the braking distance test results corresponding to the vehicle to the cloud management platform, so that the braking distance test results can be stored and displayed through the cloud management platform.

14. A vehicle, characterized in that, The vehicle includes an onboard telematics terminal TBOX and a pluggable differential positioning terminal. The TBOX includes: At least one processor; and a memory communicatively connected to said at least one processor; The memory stores a computer program that can be executed by the at least one processor, which enables the at least one processor to perform the vehicle braking distance test method according to any one of claims 1-12.

15. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that, when executed by a processor, implement the vehicle braking distance testing method according to any one of claims 1-12.

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