Safety test method and device for vehicle braking performance, host computer and test bench

Abstract

The embodiment of the application provides a kind of vehicle braking performance safety test method, device, host computer and test bench.The method is applied to the host computer in counter-force type drum brake test bench, including controlling driving motor to drive drum group to rotate synchronously with wheel after starting test, real-time acquisition wheel braking force when vehicle enters braking, and according to wheel speed dynamic adjustment motor torque, make the slip rate between drum group speed and wheel speed keep in target slip rate interval, meet stop condition and end test and output braking force data for safety verification.The method is used to reduce tire wear, friction noise and rubber odor in the process of braking safety test, at the same time, improve the fit of test working condition and vehicle actual driving working condition, thereby improve the reliability of safety test result.

Description

Technical Field

[0001] This application relates to the field of performance testing, and in particular to a safety testing method, device, host computer, and testing platform for vehicle braking performance. Background Technology

[0002] Vehicle braking performance is a core chassis performance that directly determines vehicle driving safety. Verifying whether it meets the corresponding mandatory safety standards is a key aspect of vehicle market access and in-use vehicle compliance management. Currently, the industry commonly uses reaction-type roller brake testing benches to conduct bench braking performance tests. Its basic principle is: by placing the wheel between two rotating rollers to simulate real road driving conditions; when the tester depresses the brake pedal, the friction between the wheel and the roller assembly generates braking torque, and the braking force of the wheel can be output by measuring this torque through sensors.

[0003] Existing safety testing methods typically employ the lock-up extreme value test logic: using this reaction-type roller brake test bench to test the wheel braking force data when the wheel decelerates to lock-up, and using this data to complete the safety verification of braking performance.

[0004] However, this method easily leads to continuous sliding friction between the tire and the roller assembly, causing severe tire wear, harsh noise, and a rubbery smell. At the same time, since the anti-lock braking system usually prevents the wheels from locking up completely in actual driving conditions, the data used by the existing method cannot truly reflect the safety performance of the vehicle under actual braking conditions. This results in a disconnect between the test conditions and the actual conditions, affecting the reliability of the safety test results. Summary of the Invention

[0005] This application provides a method, apparatus, host computer, and testing platform for testing the safety performance of vehicles, which can reduce tire wear, friction noise, and rubber odor during the braking safety test process, while improving the fit between the test conditions and the actual driving conditions of the vehicle, thereby improving the reliability of the safety test results.

[0006] In a first aspect, embodiments of this application provide a safety testing method for vehicle braking performance, the method being applied to a host computer in a reaction-type roller brake testing bench; the reaction-type roller brake testing bench further includes a drive motor connected to the host computer, a roller assembly connected to the drive motor, and a torque sensor; the roller assembly consists of two rollers; the method includes:

[0007] In response to the first control command, the drive motor is started to drive the roller assembly to synchronously rotate the wheels of the vehicle under test placed on it to the target speed.

[0008] In response to the second control command, the braking force of the wheels of the vehicle under test is acquired in real time through the torque sensor, and the output torque of the drive motor is adjusted based on the first speed of the wheels so that the actual slip ratio between the first speed and the second speed of the roller assembly is maintained within a preset target slip ratio range; the second control command is the command triggered when the vehicle under test starts braking;

[0009] When the preset test stop conditions are met, the drive motor is controlled to stop, and the wheel braking force data obtained from the test is output; the wheel braking force data is used to verify the safety of the vehicle's braking performance.

[0010] In one possible implementation, the step of responding to a second control command by acquiring the wheel braking force of the vehicle under test in real time via the torque sensor and adjusting the output torque of the drive motor based on the first speed of the wheel to maintain the actual slip ratio between the first speed and the second speed of the roller assembly within a preset target slip ratio range includes:

[0011] After receiving the second control command, the wheel braking force of the vehicle under test is obtained in real time through the torque sensor;

[0012] The drive motor is controlled to output a first torque until the actual difference between the actual slip ratio and the target slip ratio reaches a preset difference; the first torque is the torque that enables the roller assembly to maintain the target speed;

[0013] After the actual difference reaches the preset difference, the output torque of the drive motor is adjusted based on the first speed of the wheel so that the actual slip ratio is maintained in the target slip ratio range.

[0014] In one possible implementation, adjusting the output torque of the drive motor based on a first speed of the wheel includes:

[0015] When the actual difference reaches the preset difference, the output torque of the drive motor is reduced until the actual slip ratio reaches the lower limit of the target slip ratio range for the first time.

[0016] In one possible implementation, adjusting the output torque of the drive motor based on a first speed of the wheel further includes:

[0017] After the actual slip ratio first reaches the lower limit of the target slip ratio range, if the actual slip ratio falls below the lower limit of the target slip ratio range again, the output torque of the drive motor is increased.

[0018] If the actual slip ratio is higher than the upper limit of the target slip ratio range, then the drive motor is controlled to output reverse torque or stop.

[0019] In one possible implementation, the host computer is also connected to the on-board diagnostic system interface of the vehicle under test; the method further includes:

[0020] The wheel speed signal of the vehicle under test is read through the on-board diagnostic system interface;

[0021] The first speed of the wheel is determined based on the wheel speed signal.

[0022] In one possible implementation, the method further includes:

[0023] Obtain the maximum braking force value from the wheel braking force data;

[0024] Based on the maximum braking force, determine whether the vehicle passes the braking force safety test and generate the safety test result;

[0025] Output the security test results.

[0026] Secondly, embodiments of this application provide a safety testing device for vehicle braking performance, comprising:

[0027] The first response module is used to respond to the first control command and control the drive motor to start so as to drive the roller group to drive the wheels of the test vehicle placed on it to rotate synchronously to the target speed.

[0028] The second response module is used to respond to the second control command, acquire the wheel braking force of the vehicle under test in real time through the torque sensor, and adjust the output torque of the drive motor based on the first speed of the wheel so that the actual slip ratio between the first speed and the second speed of the roller group is maintained within the preset target slip ratio range; the second control command is the command triggered when the vehicle under test starts braking;

[0029] The control module is used to control the drive motor to stop when the preset test stop conditions are met, and to output the wheel braking force data obtained from the test; the wheel braking force data is used to verify the safety of the vehicle's braking performance.

[0030] In one possible implementation, the second response module specifically includes:

[0031] The acquisition unit is used to acquire the wheel braking force of the vehicle under test in real time through the torque sensor after acquiring the second control command;

[0032] A first control unit is used to control the drive motor to output a first torque until the actual difference between the actual slip ratio and the target slip ratio reaches a preset difference; the first torque is the torque that enables the roller assembly to maintain the target speed;

[0033] The second control unit is used to adjust the output torque of the drive motor based on the first speed of the wheel after the actual difference reaches the preset difference, so as to keep the actual slip ratio in the target slip ratio range.

[0034] In one possible implementation, the second control unit is specifically used for:

[0035] When the actual difference reaches the preset difference, the output torque of the drive motor is reduced until the actual slip ratio reaches the lower limit of the target slip ratio range for the first time.

[0036] In one possible implementation, the second control unit is further specifically used for:

[0037] After the actual slip ratio first reaches the lower limit of the target slip ratio range, if the actual slip ratio falls below the lower limit of the target slip ratio range again, the output torque of the drive motor is increased.

[0038] If the actual slip ratio is higher than the upper limit of the target slip ratio range, then the drive motor is controlled to output reverse torque or stop.

[0039] In one possible implementation, the device further includes:

[0040] The determination module is used to read the wheel speed signal of the vehicle under test through the on-board diagnostic system interface;

[0041] The first speed of the wheel is determined based on the wheel speed signal.

[0042] In one possible implementation, the device further includes:

[0043] The verification module is used to obtain the maximum braking force in the wheel braking force data;

[0044] Based on the maximum braking force, determine whether the vehicle passes the braking force safety test and generate the safety test result;

[0045] Output the security test results.

[0046] Thirdly, embodiments of this application provide a host computer, including: a memory and a processor;

[0047] The memory stores computer-executed instructions;

[0048] The processor executes computer execution instructions stored in the memory, causing the processor to perform the first aspect and / or various possible implementations of the first aspect as described above.

[0049] Fourthly, this application provides a reaction-type roller brake testing bench, including the aforementioned host computer, a drive motor connected to the host computer, a roller assembly connected to the drive motor, and a torque sensor; wherein the roller assembly consists of two rollers.

[0050] Fifthly, embodiments of this application provide a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the first aspect and / or various possible implementations of the first aspect.

[0051] In a sixth aspect, embodiments of this application provide a computer program product, including a computer program that, when executed by a processor, implements the first aspect and / or various possible implementations of the first aspect.

[0052] The vehicle braking performance safety testing method, device, host computer, and testing platform provided in this application embodiment, by adjusting the output torque of the drive motor based on the first speed of the wheel after braking during the braking test of the vehicle under test, so as to maintain the actual slip ratio between the second speed of the roller assembly and the first speed of the wheel within a preset target slip ratio range, and continuously acquiring the wheel braking force during this test, can ensure that the wheel is in a rolling state during the test, reducing the continuous sliding friction between the wheel and the roller assembly during the test, reducing tire wear, and reducing the generation of friction noise and rubber odor. At the same time, since the state is in the pre-selected target slip ratio range, rather than a completely locked state, the consistency between the roller assembly braking force test condition and the actual braking state of the vehicle can be improved, thereby improving the authenticity of the wheel braking force data used for braking performance safety verification, and achieving the effect of improving the reliability of safety test results. Attached Figure Description

[0053] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0054] Figure 1 This is a schematic diagram of a typical reaction-type roller brake testing bench.

[0055] Figure 2 This is a schematic diagram showing the change in wheel braking force of a vehicle during braking.

[0056] Figure 3A flowchart illustrating a safety testing method for vehicle braking performance provided in an embodiment of this application;

[0057] Figure 4 A schematic diagram of the structure of a reaction-type roller brake testing bench provided in this application;

[0058] Figure 5 A schematic diagram of the structure of the safety testing device for vehicle braking performance provided in this application;

[0059] Figure 6 A schematic diagram of the structure of the safety testing device for vehicle braking performance provided in this application;

[0060] Figure 7 The structural diagram of the host computer provided in this application.

[0061] Figure label:

[0062] Host computer-1; drive motor-2; first roller-31; second roller-32; wheel-4; speed measuring rod-5.

[0063] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0064] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0065] To facilitate understanding of the technical content of this application, the background technology is described in detail below:

[0066] Vehicle braking performance is a core chassis performance that directly determines vehicle driving safety. Verifying whether it meets the corresponding mandatory safety standards is a core link in vehicle market access and in-use vehicle compliance management. Therefore, braking performance safety tests are usually required in the fields of vehicle manufacturing, motor vehicle inspection and maintenance.

[0067] Current safety testing typically involves using a reaction-force roller brake test bench to test the wheel braking force of the vehicle under test, and then using the test data to evaluate the vehicle's braking safety performance. Existing safety testing methods usually employ the lock-up extreme value test logic: using a reaction-force roller brake test bench to test the wheel braking force data when the wheels decelerate to lock-up, and using this data to complete the safety verification of braking performance.

[0068] As a specific example Figure 1 This is a schematic diagram of a typical reaction-type roller brake testing bench. Figure 1 As shown, the testing platform includes a host computer 1, a drive motor 2 connected to the host computer 1, a roller assembly connected to the drive motor 2, and a torque sensor (not shown in the figure). The roller assembly consists of two rotatable rollers with a high coefficient of surface friction, namely the first roller 31 and the second roller 32. The specific testing process is as follows: Any tire 4 of the vehicle is placed between the two rollers of the roller assembly. The tester (also called the user) sends a control command to the drive motor 2 through the host computer 1 to drive the two rollers to rotate at the same constant speed (e.g., 2.5 km / h). After the roller assembly reaches the same speed as the wheel, the tester depresses the brake pedal, and the wheel speed gradually decreases until the wheel is completely locked (i.e., the wheel speed is 0). Then, the roller assembly is controlled to stop rotating. The host computer 1 measures the maximum braking force of the corresponding wheel during the aforementioned braking period (i.e., the wheel is completely locked) through the torque sensor. Based on whether this maximum braking force meets the relevant safety standards, the vehicle's braking performance is verified, thus completing this safety test. Furthermore, from... Figure 1 It can be seen that the reaction-type roller brake test bench usually also includes a speed measuring rod 5, which is used to test the vehicle speed; correspondingly, the host computer can use the test data of the speed measuring rod to determine the timing for controlling the roller group to stop rotating.

[0069] However, the aforementioned traditional testing methods, during the deceleration to lock-up process, generate significant sliding friction and even drag between the tire and the roller assembly. This "lock-up-slip" testing state leads to at least the following problems: First, severe tire wear: After the wheel locks up, intense sliding friction occurs between the tire and the rotating roller assembly, resulting in severe localized wear on the tire tread, even causing flat spots or chipping, especially for high-value tires, resulting in significant losses. Second, the testing process is not "friendly": The intense friction produces harsh noise and a burnt rubber smell, affecting operators and the environment. Third, the simulated operating conditions are distorted: On real roads, the anti-lock braking system (ABS) prevents the wheels from locking up completely, which means that the data used by existing methods cannot accurately reflect the vehicle's safety performance under actual braking conditions, resulting in a disconnect between the test conditions and actual conditions, affecting the reliability of safety test results. Fourth, testing efficiency is limited: To protect the tire, operators sometimes terminate the test prematurely or require multiple cooling tests, affecting testing efficiency and accuracy.

[0070] In response to the aforementioned technical issues, Figure 2 This is a schematic diagram illustrating the change in wheel braking force at a specific wheel of a vehicle during braking. Figure 2 It can be seen that during vehicle braking, the braking force of the wheel generally increases from 0 to its maximum value and then returns to 0. The inventors first analyzed the data in the figure as follows: Affected by the braking force, the wheel speed gradually decreases. At this time, the friction and torque generated between the tire and the roller assembly continuously increase, currently exhibiting relative sliding friction. When the vehicle speed is zero or close to zero, the vehicle reaches a fully locked state (i.e., t=2.2s). At this point, the tire and roller assembly are completely in a state of sliding friction, and the braking force reaches its peak, i.e., its maximum value. Simultaneously, the inventors analyzed the relevant provisions in GB7258-2017 "Technical Conditions for Safe Operation of Motor Vehicles," which requires that the total braking force of the entire vehicle (i.e., the sum of the braking forces of all four wheels) should not be less than 60% of the vehicle's mass. Based on the conventional design redundancy of the vehicle braking system and the relationship between wheel braking force and braking time, it can be seen that when the wheels of a compliant vehicle are in a condition close to locking but not yet fully locked, the output braking force, when accumulated from all four wheels, can meet the standard requirements.

[0071] In view of this, the inventors propose a braking performance testing method based on a target slip ratio range: a target slip ratio range corresponding to the condition where the wheel is close to locking but not completely locked is pre-set, the wheel braking force data when the actual slip ratio between the wheel and the roller assembly falls into this range is collected, and the vehicle braking performance safety verification is completed based on this data; the core principle of this method is that when the wheel is running within the target slip ratio range, the wheel can still maintain a rolling state, which can effectively avoid the problems of severe tire wear and friction noise caused by wheel lock-up; at the same time, the wheel can output a large braking force under this condition, and the collected braking force data can be directly used to determine whether the vehicle braking performance meets the relevant safety standards.

[0072] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0073] Figure 3 This is a flowchart illustrating a safety testing method for vehicle braking performance provided in an embodiment of this application. The method is applied to a host computer in a reaction-type roller brake testing bench. The reaction-type roller brake testing bench also includes a drive motor connected to the host computer, a roller assembly connected to the drive motor, and a torque sensor. Figure 3 As shown, the method includes:

[0074] S101: In response to the first control command, control the drive motor to start, so as to drive the roller assembly to drive the wheels of the test vehicle placed on it to rotate synchronously to the target speed.

[0075] In detail, in this application, the reaction-type roller brake test bench serves as a test execution platform, including a host computer, a drive motor connected to the host computer, a roller assembly connected to the drive motor, and a torque sensor. The host computer, as the method execution and control center, is used to receive user operations, send generator control signals, and receive test data; the drive motor is used to output mechanical torque and drive each roller in the roller assembly to rotate synchronously; the roller assembly consists of two rollers and is used to support a single wheel of the vehicle under test; the roller assembly is equipped with a torque sensor to collect the braking reaction torque it bears, providing raw data support for calculating the braking force of the corresponding wheel.

[0076] In practical applications, a reaction-type roller brake testing bench can be configured with multiple roller groups, such as two or four. For example, if two roller groups are configured, the reaction-type roller brake testing bench can simultaneously perform braking force tests on the left and right tires of the same axle (front or rear axle) of a vehicle in a single operation. Depending on actual testing needs, more roller groups can be configured in the reaction-type roller brake testing bench, thus eliminating any limitation on the number of roller groups in the bench. Figure 3 As shown, this roller assembly integrates two independent single-wheel brake detection units, comprising a total of four rollers. In practical applications, this roller assembly can be used to simultaneously and independently detect the braking force data of the left and right wheels of the same axle. It should be noted that for reaction-type roller brake testing benches with different numbers of roller assemblies, the detection principle and control logic for a single wheel are the same.

[0077] In practical applications, the vehicle to be tested must first be driven into the testing station of the reaction-type roller brake test bench, with the wheels of the vehicle to be tested positioned between two rollers in the roller assembly. Next, after the vehicle completes its parking and positioning, the host computer receives a first control command and, in response to this command, controls the drive motor to start, thereby driving the roller assembly to synchronously rotate the wheels of the vehicle to be tested to the target speed.

[0078] The first control command is used to trigger the test start phase. This first control command can be input by the user through the human-machine interface of the host computer, specifically through touch screen buttons, keyboard buttons, mouse clicks on virtual buttons, or external control box start signals, etc.

[0079] Specifically, after receiving the first control command, the host computer sends a start message or level control signal to the drive motor controller, causing the drive motor to enter the controlled output state from a stationary state. After the drive motor starts, it drives each roller in the roller group to rotate synchronously through the coupling, reduction mechanism, or direct drive structure. A circumferential friction force is formed between the roller and the wheel contact surface, which in turn drives the wheel to rotate until each roller and wheel reaches the target speed. Then, the drive motor maintains the current output torque and waits for the vehicle under test to enter the braking operation stage.

[0080] The target speed can be set according to the calibration parameters of the test bench to the linear speed corresponding to the low-speed driving state of the vehicle, such as 2.5 km / h.

[0081] S102: In response to the second control command, the wheel braking force of the vehicle under test is obtained in real time through the torque sensor, and the output torque of the drive motor is adjusted based on the first speed of the wheel so that the actual slip ratio between the first speed and the second speed of the roller group is maintained within the preset target slip ratio range.

[0082] The second control command is triggered when the vehicle under test initiates braking, initiating the braking operation phase. Wheel braking force is the core test quantity characterizing wheel braking capability; the first speed is the current actual linear velocity of the wheel; the second speed is the current actual linear velocity of the two rollers, determined by the output torque of the drive motor; the output torque is the output quantity of the drive motor; the actual slip ratio is a control index determined based on the speed difference between the first wheel speed and the second roller speed. The preset target slip ratio range is the slip control range required to be maintained during the test. Specifically, the slip ratio calculation formula is, for example, multiplying the value obtained by comparing the difference between the first and second speeds with the second speed by 100%; the target slip ratio is, for example, 80% to 90%.

[0083] In this step, after receiving the second control command, the host computer will obtain the braking force of the wheel above the roller assembly in the vehicle in real time through the torque sensor, so as to obtain the wheel braking force at each moment during the entire braking operation phase, which will be summarized and output as wheel braking force data at the end of the test. At the same time, after receiving the second control command, it is also necessary to determine the second speed that the roller assembly needs to reach in real time based on the first speed of the wheel and the target slip ratio range, and determine the output torque adjustment amount of the drive motor according to the second speed, so as to adjust the output torque of the drive motor, thereby maintaining the actual slip ratio between the first speed and the second speed of the roller assembly within the preset target slip ratio range.

[0084] In practical applications, the aforementioned output torque adjustment can also be corrected by combining the trend of wheel braking force change and the trend of first speed decrease. When a rapid increase in braking force and a sharp decrease in first speed are detected, the host computer adjusts the torque correction range within the current control cycle so that the roller speed can more timely approach the wheel speed.

[0085] In addition, the wheel braking force of the vehicle under test is obtained by a torque sensor. Specifically, during braking, the friction force applied by the wheel to the roller forms a braking reaction torque. The torque sensor collects the magnitude of this braking reaction torque in real time and uploads the torque signal to the host computer. The host computer converts the collected torque data into the corresponding instantaneous wheel braking force according to the pre-calibrated torque-braking force conversion relationship, and obtains the time-series curve of the wheel braking force changing over time.

[0086] In one possible implementation, the second control command can be input by the tester through the human-machine interface of the host computer after confirming that the roller assembly and wheels have rotated synchronously to the target speed and the brake pedal is depressed. Specifically, it can be input via touchscreen buttons, keyboard buttons, mouse clicks on virtual buttons, or an external control box start signal. In another implementation, the host computer can also be connected to the vehicle's bus; correspondingly, the second control command can be automatically generated by the host computer after detecting that both the first and second speeds have reached the target speed, and then controlling the vehicle to enter braking mode via the bus.

[0087] In practical applications, the host computer needs to acquire the first speed of the wheel and the second speed of the roller assembly in real time, and adjust the output torque of the drive motor based on the acquired speeds. The second speed is determined based on the range between the first speed and the target slip ratio. The first speed can be directly obtained through... Figure 1 The speed is measured by a speed sensor, such as the speed measuring rod, in the reaction-type roller brake test bench shown.

[0088] Understandably, the key to control in this case lies in the rapid and accurate acquisition of the wheel's initial speed. In view of this, in one possible implementation, this application also proposes a method for acquiring wheel speed in a test scenario, specifically including: reading the wheel speed signal of the vehicle under test through the on-board diagnostic system interface; and determining the wheel's initial speed based on the wheel speed signal.

[0089] Figure 4 This is a schematic diagram of the structure of a reaction-type roller brake testing bench provided in this application. Figure 4 As shown, based on the typical testing bench architecture, the mechanism provided in this application interfaces the host computer with the on-board diagnostics (OBD) system of the vehicle under test, and eliminates the need for a speed measuring rod. During operation, after establishing communication with the vehicle under test, the host computer reads wheel speed signals via the on-board diagnostics interface according to a preset cycle, performs validity checks and necessary unit conversions on the collected signals, and then determines the first rotational speed of the current wheel.

[0090] After adopting the above method, the first wheel speed is directly obtained and determined by the on-board diagnostic system interface. The wheel speed data source is clear, the real-time reading is high, and there is no need to add an additional contact speed measuring component, so that the speed parameters on which the subsequent slip ratio control is based are more stable and consistent.

[0091] Based on the above analysis, this step uses the first rotational speed as the core feedback quantity and links it with the second rotational speed to dynamically control the output torque of the drive motor. This makes the test conditions close to the force and speed change relationship during the actual vehicle braking process, while reducing the degree of continuous sliding friction between the tire and the roller, reducing the mechanical load, and improving the continuity and stability of the test data.

[0092] S103: When the preset test stop conditions are met, control the drive motor to stop and output the wheel braking force data obtained from the test.

[0093] Among them, wheel braking force data is used to verify the safety of vehicle braking performance.

[0094] In this step, the preset test stop conditions are used to define the test termination time, and the wheel braking force data is output as the test result for subsequent safety analysis of braking performance.

[0095] Specifically, the test stop conditions can be pre-written into the host computer configuration file or directly set by the test item parameters before the test begins. These conditions can include any one or more combinations of the following: the test duration reaches the set upper limit, the driver releases the brake pedal, the user inputs a stop command, and the equipment detects an abnormal state.

[0096] Optionally, the host computer generates relevant test information while outputting wheel braking force data. The relevant test information includes at least vehicle identification, test time, test station, wheel braking force curve, peak braking force, first speed curve, second speed curve, actual slip ratio curve, and the reason for triggering the stopping condition.

[0097] In practice, the host computer compares the current test status with the above conditions in each control cycle. When it determines that the test stop condition is met, it sends a stop control signal to the drive motor, causing the drive motor to exit the torque output state and the roller to stop actively driving the wheel.

[0098] The drive motor can be stopped using a controlled torque reduction shutdown method, whereby the host computer first gradually reduces the output torque to zero at a preset slope, and then cuts off the running enable to reduce mechanical shock; in the event of a fault, communication interruption, or safety protection trigger, a fast shutdown strategy can also be executed directly.

[0099] After the stop command is issued, the host computer also needs to process the collected wheel braking force data. This processing includes forming a complete dataset according to time series or sampling sequences. Specific data may include wheel braking force at each moment, and optionally, the first rotational speed, second rotational speed, and actual slip ratio at each moment. Output methods may include displaying on the host computer interface, writing to a local database, generating a detection report file, or sending it to an external management system via a communication interface.

[0100] Safety analysis of braking performance is based on the output wheel braking force data. For example, wheel braking force curves and peak braking forces can be extracted from the wheel braking force data, or directly obtained from relevant test information. Based on this data, it can be determined whether the vehicle's braking performance meets the relevant safety requirements.

[0101] The vehicle braking performance safety testing method, device, host computer, and testing platform provided in this application embodiment, by adjusting the output torque of the drive motor based on the first speed of the wheel after braking during the braking test of the vehicle under test, so as to maintain the actual slip ratio between the second speed of the roller assembly and the first speed of the wheel within a preset target slip ratio range, and continuously acquiring the wheel braking force during this test, can ensure that the wheel is in a rolling state during the test, reducing the continuous sliding friction between the wheel and the roller assembly during the test, reducing tire wear, and reducing the generation of friction noise and rubber odor. At the same time, since the state is in the pre-selected target slip ratio range, rather than a completely locked state, the consistency between the roller assembly braking force test condition and the actual braking state of the vehicle can be improved, thereby improving the authenticity of the wheel braking force data used for braking performance safety verification, and achieving the effect of improving the reliability of safety test results.

[0102] Furthermore, Embodiment 2 of this application provides a method for conducting safety tests on vehicle braking performance using the aforementioned reaction-type roller brake test bench, specifically including the following steps A1 to A7:

[0103] Step A1: Place the vehicle's tires between the two rollers of the roller assembly.

[0104] Step A2: The user triggers the first control command in the host computer.

[0105] Step A3: The host computer responds to the first control command and controls the drive motor to start, so as to drive the roller assembly to drive the wheels of the vehicle under test placed on it to rotate synchronously to the target speed.

[0106] Step A4: The user presses the vehicle's brake pedal to initiate braking, and at the same time, triggers a second control command in the host computer.

[0107] Step A5: In response to the second control command, the host computer acquires the wheel braking force of the vehicle under test in real time through the torque sensor, and adjusts the output torque of the drive motor based on the first wheel speed to maintain the actual slip ratio between the first speed and the second speed of the roller assembly within the preset target slip ratio range. Specifically, this includes steps 51 to 53 as follows:

[0108] Step 51: After receiving the second control command, the wheel braking force of the vehicle under test is obtained in real time through the torque sensor.

[0109] In this step, triggered by the second control command, the host computer begins to acquire the wheel braking force of the vehicle under test in real time through the torque sensor throughout the entire braking operation phase.

[0110] Step 52: Control the drive motor to output the first torque until the actual difference between the actual slip ratio and the target slip ratio reaches the preset difference.

[0111] The first torque is the torque that keeps the roller assembly at the target speed.

[0112] In this step, after the second control command is triggered, the host computer will monitor the actual slip ratio in real time and first send a torque holding command to the drive motor, causing it to output a first torque corresponding to the target speed. Under the action of this torque, the drive motor maintains the roller running at the target speed until the actual difference between the actual slip ratio and the target slip ratio reaches a preset difference. The first torque can be obtained by the motor controller based on the roller inertia, load resistance, and target speed.

[0113] Step 53: After the actual difference reaches the preset difference, adjust the output torque of the drive motor based on the first speed of the wheel to keep the actual slip ratio within the target slip ratio range.

[0114] In this step, when the actual difference between the actual slip ratio and the target slip ratio reaches the preset difference, the system switches to a closed-loop adjustment mode based on the first wheel speed and corrects the output torque of the drive motor according to the preset sampling period so that the slip ratio is kept within the target slip ratio range.

[0115] In one possible implementation, step 53 includes steps a through c:

[0116] Step a: When the actual difference reaches the preset difference, reduce the output torque of the drive motor until the actual slip ratio reaches the lower limit of the target slip ratio range for the first time.

[0117] In this step, after the actual difference reaches the preset difference, and before the actual slip ratio first reaches the lower limit of the target slip ratio range, the host computer will control the reduction of the output torque of the drive motor to slow down the growth of the difference between the first speed and the second speed.

[0118] The preset difference can be determined based on the actual application of the scheme, such as 5%, 10%, 12%, etc.

[0119] The method provided in this step allows the actual slip ratio to smoothly and slowly enter the target slip ratio range, thereby avoiding slip ratio overshoot and improving the stability and accuracy of slip ratio control.

[0120] Step b: After the actual slip ratio reaches the lower limit of the target slip ratio range for the first time, if the actual slip ratio falls below the lower limit of the target slip ratio range again, the output torque of the drive motor is increased.

[0121] In this step, after the actual slip ratio first reaches the lower limit of the target slip ratio range, the actual slip ratio will be monitored in real time to see if it is within the target slip ratio range. When the actual slip ratio falls below the lower limit of the target slip ratio range again, the output torque of the drive motor will be increased to increase the braking load, thereby enabling the actual slip ratio to quickly recover to the target slip ratio range.

[0122] Optionally, after the actual slip ratio first reaches the lower limit of the target slip ratio range, and then after the actual slip ratio falls below the lower limit of the target slip ratio range again for a period of time, the output torque of the drive motor can be increased, while during this period, the output torque of the drive motor can be kept constant.

[0123] It is understandable that when the actual slip ratio is within the target slip ratio range, the output torque of the drive motor can remain unchanged, or it can be adaptively adjusted according to the changes in the actual slip ratio.

[0124] Step c: If the actual slip ratio is higher than the upper limit of the target slip ratio range, control the drive motor to output reverse torque or stop the machine.

[0125] In this step, when the actual slip ratio falls below the lower limit of the target slip ratio range again, the drive motor can be controlled to output reverse torque or stop, so that the actual slip ratio can be restored to the target slip ratio range, thereby allowing the wheel to resume rolling.

[0126] The method provided in steps a to c above allows the actual slip ratio of the wheel to smoothly enter the target slip ratio range after the vehicle braking is initiated, thereby avoiding slip ratio overshoot and improving the stability and accuracy of slip ratio control. At the same time, it also ensures that in the subsequent control phase, when the actual slip ratio exceeds the critical value of the target slip ratio range, the actual slip ratio can be quickly restored to the target slip ratio range, thus ensuring that the actual slip ratio can be stably maintained within the target slip ratio range during the braking phase.

[0127] In practical applications, the feedback control process in this step can be achieved by using PID control algorithms or fuzzy control algorithms to perform closed-loop adjustment of the output torque of the drive motor. For example, the deviation between the actual slip ratio and the target slip ratio range can be used as the control input, and the output torque or output speed of the drive motor can be used as the control output. By adjusting the driving force of the roller in real time, the actual slip ratio can be stably maintained within the preset target slip ratio range.

[0128] The method provided in steps 51 to 53 above does not rely on the wheel being locked for a long time during the braking force acquisition process. The correspondence between the test data and the braking dynamic process is more stable, and the continuous sliding wear between the roller surface and the tire tread can be reduced, as well as the load fluctuation during the test process can be reduced.

[0129] Step A6: When the preset test stop conditions are met, the host computer controls the drive motor to stop and outputs the wheel braking force data obtained from the test.

[0130] Step A7: The host computer verifies the vehicle's braking performance and safety based on the wheel braking force data. This specifically includes steps 71 to 73:

[0131] Step 71: Obtain the maximum braking force from the wheel braking force data.

[0132] In this step, after the host computer completes the output of braking force data, it can perform peak search processing on the data, compare the braking force values ​​point by point according to the sampling time sequence, determine the value corresponding to the maximum braking force and the time of its occurrence, and write the maximum value into the test record.

[0133] Step 72: Determine whether the vehicle passes the braking force safety test based on the maximum braking force value, and generate the safety test results.

[0134] In this step, the host computer can compare the maximum braking force with the pre-stored test threshold. When the maximum braking force reaches or exceeds the safety threshold, the vehicle is determined to have passed the braking force safety test; when the maximum braking force is lower than the threshold, the vehicle is determined to have failed the braking force safety test, and the corresponding safety test result is generated accordingly.

[0135] Among them, the safety threshold can be preset in the host computer by braking-related safety standards (such as GB7258-2017 "Technical Conditions for Safe Operation of Motor Vehicles") and vehicle model parameters, so as to match the braking requirements corresponding to different vehicle types.

[0136] Step 73: Output the security test results.

[0137] In this step, when outputting the safety test results, the host computer can display the judgment conclusion on the operation interface and simultaneously store it in the test database or generate a test report file. If necessary, it can also send it to an external management terminal through the communication interface so that the test conclusion and the maximum braking force are retained together.

[0138] The method provided in steps 72 to 73 above, since the determination is directly based on the maximum value in the braking force data, can correlate the key braking performance indicators in the test process with the final conclusion, so that the output results have clear data basis and are convenient for subsequent traceability and verification.

[0139] The vehicle braking performance safety testing method provided in this application has at least the following technical effects: First, it significantly reduces wheel wear: Since the wheels do not lock up or slip during the entire test, the rolling motion between the tire and the roller is the main process, with slight slippage as a secondary process, which significantly reduces tread wear, especially suitable for high-performance tires and heavy-duty tires; Second, it is closer to actual working conditions: This method simulates the "rolling and slipping" state of a vehicle under emergency braking with an ABS system on the road, and the measured maximum braking force is more correlated with the actual braking force of the vehicle, so the test data can more realistically reflect the actual braking safety of the vehicle; Third, it improves testing comfort: It eliminates the sharp noise and burning rubber smell caused by lock-up and slippage, improving the testing environment; Fourth, it protects the testing equipment: It avoids roller surface wear and drive motor overload caused by severe sliding friction, extending the life of the test bench; Fifth, it has high testing efficiency: It does not require interruption of cooling, and stable results can be obtained in one continuous test, with a total time comparable to or shorter than traditional methods.

[0140] Figure 5 A schematic diagram of the structure of the safety testing device for vehicle braking performance provided in this application is shown below. Figure 5 As shown, the vehicle braking performance safety testing device 20 provided in this embodiment includes:

[0141] The first response module 201 is used to respond to the first control command and control the drive motor to start so as to drive the roller group to drive the wheels of the vehicle under test placed on it to rotate synchronously to the target speed.

[0142] The second response module 202 is used to respond to the second control command, acquire the wheel braking force of the vehicle under test in real time through the torque sensor, and adjust the output torque of the drive motor based on the first speed of the wheel so that the actual slip ratio between the first speed and the second speed of the roller group is maintained within the preset target slip ratio range; the second control command is the command triggered when the vehicle under test starts braking.

[0143] The control module 203 is used to control the drive motor to stop when the preset test stop conditions are met, and to output the wheel braking force data obtained from the test; the wheel braking force data is used to verify the safety of the vehicle's braking performance.

[0144] The vehicle braking performance safety testing device 20 provided in this embodiment can execute the method provided in the above method embodiment. Its implementation principle and technical effect are similar, and will not be described in detail here.

[0145] Figure 6 A schematic diagram of the structure of the safety testing device for vehicle braking performance provided in this application is shown below. Figure 6 As shown, based on the above embodiments, the vehicle braking performance safety testing device 20 provided in this embodiment further includes:

[0146] The determination module 204 is used to read the wheel speed signal of the vehicle under test through the on-board diagnostic system interface;

[0147] The initial speed of the wheel is determined based on the wheel speed signal.

[0148] Verification module 205 is used to obtain the maximum value of braking force in the wheel braking force data;

[0149] The vehicle's braking force safety test is determined based on its maximum braking force, and the safety test results are generated.

[0150] Output the security test results.

[0151] In one possible implementation, the second response module 202 specifically includes:

[0152] The acquisition unit is used to acquire the wheel braking force of the vehicle under test in real time through the torque sensor after acquiring the second control command;

[0153] The first control unit is used to control the drive motor to output a first torque until the actual difference between the actual slip ratio and the target slip ratio reaches a preset difference; the first torque is the torque that keeps the roller assembly at the target speed.

[0154] The second control unit is used to adjust the output torque of the drive motor based on the first speed of the wheel after the actual difference reaches the preset difference, so as to keep the actual slip ratio within the target slip ratio range.

[0155] In one possible implementation, the second control unit is specifically used for:

[0156] When the actual difference reaches the preset difference, the output torque of the drive motor is reduced until the actual slip ratio reaches the lower limit of the target slip ratio range for the first time.

[0157] In one possible implementation, the second control unit is further specifically used for:

[0158] If the actual slip ratio falls below the lower limit of the target slip ratio range again after the actual slip ratio reaches the lower limit of the target slip ratio range for the first time, the output torque of the drive motor will be increased.

[0159] If the actual slip ratio is higher than the upper limit of the target slip ratio range, the drive motor will be controlled to output reverse torque or stop.

[0160] The vehicle braking performance safety testing device 20 provided in this embodiment can execute the method provided in the above method embodiment. Its implementation principle and technical effect are similar, and will not be described in detail here.

[0161] Figure 7The structural diagram of the host computer provided in this application is as follows: Figure 7 As shown, the host computer 30 provided in this embodiment includes at least one processor 301 and a memory 302. Optionally, the host computer 30 also includes a communication component 303. The processor 301, memory 302, and communication component 303 are connected via a bus 304.

[0162] In a specific implementation, at least one processor 301 executes computer execution instructions stored in memory 302, causing at least one processor 301 to perform the above-described method.

[0163] The specific implementation process of processor 301 can be found in the above method embodiments, and its implementation principle and technical effect are similar. It will not be repeated here.

[0164] In the above embodiments, it should be understood that the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in this invention can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor.

[0165] The memory may include read-only memory and random access memory. The memory may be volatile or non-volatile, or may include both. Non-volatile memory may include read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory may include random access memory (RAM), which serves as an external cache. Many forms of RAM are available by way of example, but not limitation. Examples include Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), Synchronous DRAM (SDRAM), Double Data Rate SDRAM (DDR SDRAM), Enhanced Synchronous DRAM (ESDRAM), Sync Link DRAM (SLDRAM), and Direct Rambus RAM (DR RAM).

[0166] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of illustration, the buses shown in the accompanying drawings are not limited to a single bus or a single type of bus.

[0167] This application also provides a reaction-type roller brake test bench, including the host computer in the above embodiment, a drive motor connected to the host computer, a roller assembly connected to the drive motor, and a torque sensor; wherein the roller assembly consists of two rollers.

[0168] This application also provides a computer program product, including a computer program that, when executed, implements the above-described method.

[0169] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed, implement the above-described method.

[0170] The aforementioned readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as SRAM, EEPROM, EPROM, PROM, ROM, magnetic storage, flash memory, magnetic disk, or optical disk. The readable storage medium can be any available medium accessible to a general-purpose or special-purpose computer.

[0171] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can reside within an ASIC. Alternatively, the processor and the readable storage medium can exist as discrete components in a device.

[0172] The division of units is merely a logical functional division; in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0173] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0174] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0175] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, ROM, RAM, magnetic disks, or optical disks.

[0176] Those skilled in the art will understand that all or part of the steps of the above-described method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments; and the aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0177] The above embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention.

[0178] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A safety testing method for vehicle braking performance, characterized in that, The method is applied to the host computer in a reaction-type roller brake testing bench; the reaction-type roller brake testing bench further includes a drive motor connected to the host computer, a roller assembly connected to the drive motor, and a torque sensor; the roller assembly consists of two rollers; the method includes: In response to the first control command, the drive motor is started to drive the roller assembly to synchronously rotate the wheels of the vehicle under test placed on it to the target speed. In response to the second control command, the braking force of the wheels of the vehicle under test is acquired in real time through the torque sensor, and the output torque of the drive motor is adjusted based on the first speed of the wheels so that the actual slip ratio between the first speed and the second speed of the roller assembly is maintained within a preset target slip ratio range; the second control command is the command triggered when the vehicle under test starts braking; When the preset test stop conditions are met, the drive motor is controlled to stop, and the wheel braking force data obtained from the test is output; the wheel braking force data is used to verify the safety of the vehicle's braking performance.

2. The method according to claim 1, characterized in that, The step of responding to a second control command by acquiring the wheel braking force of the vehicle under test in real time via the torque sensor and adjusting the output torque of the drive motor based on the first speed of the wheel to maintain the actual slip ratio between the first speed and the second speed of the roller assembly within a preset target slip ratio range includes: After receiving the second control command, the wheel braking force of the vehicle under test is obtained in real time through the torque sensor; The drive motor is controlled to output a first torque until the actual difference between the actual slip ratio and the target slip ratio reaches a preset difference; the first torque is the torque that enables the roller assembly to maintain the target speed; After the actual difference reaches the preset difference, the output torque of the drive motor is adjusted based on the first speed of the wheel so that the actual slip ratio is maintained in the target slip ratio range.

3. The method according to claim 2, characterized in that, Adjusting the output torque of the drive motor based on the first speed of the wheel includes: When the actual difference reaches the preset difference, the output torque of the drive motor is reduced until the actual slip ratio reaches the lower limit of the target slip ratio range for the first time.

4. The method according to claim 2, characterized in that, The adjustment of the output torque of the drive motor based on the first speed of the wheel further includes: After the actual slip ratio first reaches the lower limit of the target slip ratio range, if the actual slip ratio falls below the lower limit of the target slip ratio range again, the output torque of the drive motor is increased. If the actual slip ratio is higher than the upper limit of the target slip ratio range, then the drive motor is controlled to output reverse torque or stop.

5. The method according to any one of claims 1 to 4, characterized in that, The host computer is also connected to the on-board diagnostic system interface of the vehicle under test; the method further includes: The wheel speed signal of the vehicle under test is read through the on-board diagnostic system interface; The first speed of the wheel is determined based on the wheel speed signal.

6. The method according to any one of claims 1 to 4, characterized in that, The method further includes: Obtain the maximum braking force value from the wheel braking force data; Based on the maximum braking force, determine whether the vehicle passes the braking force safety test and generate the safety test result; Output the security test results.

7. A safety testing device for vehicle braking performance, characterized in that, include: The first response module is used to respond to the first control command and control the drive motor to start so as to drive the roller group to drive the wheels of the test vehicle placed on it to rotate synchronously to the target speed. The second response module is used to respond to the second control command, acquire the wheel braking force of the vehicle under test in real time through the torque sensor, and adjust the output torque of the drive motor based on the first speed of the wheel so that the actual slip ratio between the first speed and the second speed of the roller group is maintained within the preset target slip ratio range. The second control command is the command triggered when the vehicle under test starts braking; The control module is used to control the drive motor to stop when the preset test stop conditions are met, and to output the wheel braking force data obtained from the test. The wheel braking force data is used to verify the safety of the vehicle's braking performance.

8. A host computer, characterized in that, include: Memory, processor; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory, causing the processor to perform the method as described in any one of claims 1-6.

9. A reaction-type roller brake inspection bench, characterized in that, It includes the host computer as described in claim 8, a drive motor connected to the host computer, a roller assembly connected to the drive motor, and a torque sensor, wherein the roller assembly consists of two rollers.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method as described in any one of claims 1-6.

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