Method, device, equipment and medium for testing tire longitudinal slip characteristic curve

Abstract

The application discloses a kind of tire longitudinal slip characteristic curve test method, device, equipment and medium, the tire longitudinal slip characteristic curve test method includes: obtaining the radius of the tire to be tested and tire inertia;Control the whole vehicle containing the tire to be tested is in acceleration state and is tested, obtains the whole vehicle acceleration, wheel speed and drive shaft torque;The whole vehicle acceleration and wheel speed in test time period are respectively processed, and the whole vehicle speed and wheel acceleration are obtained;According to the first relationship model, the slip rate of the tire to be tested is calculated;According to the second relationship model, the longitudinal force of the tire to be tested is calculated;According to the slip rate and longitudinal force of the tire to be tested, the longitudinal slip characteristic curve of the tire to be tested is determined.The method reduces test cost, reduces test cycle and test result is consistent with actual vehicle characteristics.

Description

Technical Field

[0001] This invention relates to the field of vehicle testing, and more particularly to a method, apparatus, equipment, and medium for testing the longitudinal slip characteristic curve of a tire. Background Technology

[0002] In existing technologies, the longitudinal slip characteristic curve of a tire is typically required as input for tire selection, tire dynamics modeling, and vehicle dynamics simulation analysis. This improves the accuracy of vehicle modeling and simulation, thereby providing users with a better driving experience under different driving environments. Current methods for testing tire longitudinal slip characteristic curves primarily involve using tire test benches. The main principle is to apply load to a rotating drum dynamometer while simultaneously measuring the tire's rotational and translational speeds, as well as the torque of the dynamometer, to obtain the tire's longitudinal force-slip ratio curve. This method requires expensive testing equipment, typically necessitates testing by specific suppliers, and involves long testing cycles and significant costs. Furthermore, the test results obtained using tire test benches differ considerably from those of real vehicles, significantly impacting the accuracy of dynamics modeling and vehicle simulation analysis. Summary of the Invention

[0003] Based on this, a test method, apparatus, equipment and medium for tire longitudinal slip characteristic curves are provided to solve the problems of long test time, high test cost and large error between test results and actual vehicle conditions in the prior art.

[0004] In a first aspect, embodiments of the present invention provide a method for testing the longitudinal slip characteristic curve of a tire, the method comprising the following steps:

[0005] Obtain the radius and inertia of the tire to be tested;

[0006] The vehicle containing the tire to be tested is controlled to be under acceleration and tested to obtain the vehicle acceleration, wheel speed and drive shaft torque during the test period.

[0007] The vehicle acceleration and wheel speed during the test period are processed to obtain the vehicle speed and wheel acceleration during the test period.

[0008] Based on the wheel speed, vehicle speed and radius of the tire under test during the test period, and combined with the first relationship model between the tire slip ratio and the wheel speed and vehicle speed, the slip ratio of the tire under test during the test period is calculated.

[0009] Based on the drive shaft torque, wheel acceleration, radius of the tire under test, and tire inertia during the test period, and combined with the second relationship model between the longitudinal force of the tire and the drive shaft torque and wheel acceleration, the longitudinal force of the tire under test during the test period is calculated.

[0010] Based on the slip ratio and longitudinal force of the tire under test during the test period, the longitudinal slip characteristic curve of the tire under test is determined.

[0011] Secondly, embodiments of the present invention provide a testing device for the longitudinal slip characteristic curve of a tire, the device comprising:

[0012] The relational model parameter acquisition module is used to obtain the radius and tire inertia of the tire under test;

[0013] The test parameter acquisition module is used to control the whole vehicle containing the test tire to be in an accelerated state to obtain the vehicle acceleration, wheel speed and drive shaft torque during the test period.

[0014] The test parameter processing module is used to process the vehicle acceleration and wheel speed during the test time period to obtain the vehicle speed and wheel acceleration during the test time period.

[0015] The slip ratio calculation module is used to calculate the slip ratio of the tire under test during the test period based on the wheel speed, vehicle speed and radius of the tire under test during the test period, combined with the first relationship model between the tire slip ratio and the wheel speed and vehicle speed.

[0016] The longitudinal force calculation module is used to calculate the longitudinal force of the tire under test during the test period based on the drive shaft torque, wheel acceleration, radius of the tire under test, and tire inertia during the test period, combined with the second relationship model between the longitudinal force of the tire and the drive shaft torque and wheel acceleration.

[0017] The characteristic curve generation module is used to determine the longitudinal slip characteristic curve of the tire under test based on the slip ratio and longitudinal force of the tire under test during the test time period.

[0018] Thirdly, embodiments of the present invention provide a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the above-described method for testing the longitudinal slip characteristic curve of a tire.

[0019] Fourthly, embodiments of the present invention provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the above-described method for testing the longitudinal slip characteristic curve of a tire.

[0020] Fifthly, embodiments of the present invention provide a computer program product that, when run on a terminal device, causes the terminal device to execute the steps of the above-described method for testing the longitudinal slip characteristic curve of a tire.

[0021] The aforementioned test method, apparatus, equipment, and medium for the longitudinal slip characteristic curve of a tire are tested by controlling the entire vehicle under acceleration. Based on the first relationship model between tire slip ratio and wheel speed and vehicle speed, and the second relationship model between tire longitudinal force and drive axle torque and wheel acceleration, the slip ratio and longitudinal force of the tire under test during the test period are calculated respectively. Combined with the measured tire slip ratio and longitudinal force, the longitudinal slip characteristic curve of the tire under test is determined.

[0022] Through the above steps, compared with the existing method of testing tire longitudinal slip characteristic curves using tire test benches, this invention is based on existing equipment and does not incur additional costs, greatly saving testing costs. At the same time, the method of obtaining tire longitudinal force in this invention is simple to operate, so the required testing cycle is shorter. Furthermore, this invention tests tire longitudinal force characteristics based on the whole vehicle condition, and the test results have a smaller error compared with the actual vehicle condition, which can better reflect the tire characteristics during actual vehicle operation and is beneficial to the development and control of the whole vehicle. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the 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.

[0024] Figure 1 This is a schematic diagram of an application environment for a method for testing the longitudinal slip characteristic curve of a tire according to an embodiment of the present invention;

[0025] Figure 2 This is a flowchart of a method for testing the longitudinal slip characteristic curve of a tire in one embodiment of the present invention;

[0026] Figure 3 This is a flowchart of a method for obtaining drive shaft torque in a tire longitudinal slip characteristic curve test method according to an embodiment of the present invention;

[0027] Figure 4This is a flowchart of the test parameter processing in the test method for the tire longitudinal slip characteristic curve in one embodiment of the present invention;

[0028] Figure 5 This is a schematic diagram of a test device for the longitudinal slip characteristic curve of a tire in one embodiment of the present invention;

[0029] Figure 6 This is a schematic diagram of a computer device according to an embodiment of the present invention;

[0030] Figure 7 This is a characteristic curve of slip ratio versus time in the test method for the longitudinal slip characteristic curve of a tire in one embodiment of the present invention;

[0031] Figure 8 This is the characteristic curve of longitudinal force versus time in the test method for the longitudinal slip characteristic curve of a tire in one embodiment of the present invention;

[0032] Figure 9 This is a tire longitudinal slip characteristic curve in one embodiment of the present invention. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] The test method for the longitudinal slip characteristic curve of tires provided in this application can be applied to, for example... Figure 1 In this application environment, the client (computer device) communicates with the server via a network. The client obtains a test request for the tire's longitudinal slip characteristic curve and sends it to the server. Upon receiving the test request, the server processes it accordingly and responds. The computer device can be, but is not limited to, various personal computers, laptops, smartphones, tablets, and portable wearable devices. The server can be implemented using a standalone server or a server cluster consisting of multiple servers.

[0035] In one embodiment, such as Figure 2 As shown, a test method for the longitudinal slip characteristic curve of a tire is provided, which is then applied to... Figure 1 Taking the server-side as an example, the explanation includes the following steps:

[0036] S10: Obtain the radius and inertia of the tire to be tested.

[0037] The radius of the tire under test is typically calculated using a tire load formula. First, the load factor of the tire is obtained from the relevant technical manual provided by the tire manufacturer. This load factor is a coefficient related to the tire's size and structure. Second, the load on the tire is calculated based on factors such as the vehicle's total weight, axle load distribution, and tire load distribution coefficient. Finally, the radius of the tire can be calculated using the tire load formula: Tire radius = Load / Load factor.

[0038] The inertia of rotating components such as tires, rims, and steering discs is obtained through experiments or simulations. The inertia of these components is then summed to obtain the total inertia, which is the tire inertia.

[0039] S20: Control the vehicle containing the tire to be tested to be in an accelerated state for testing, and obtain the vehicle acceleration, wheel speed and drive shaft torque during the test period.

[0040] To ensure the test results closely match real-world vehicle characteristics, the vehicle, containing the tire under test, is controlled under acceleration during the test. Vibration sensors are placed at intervals within a set distance from the tire to measure the vehicle's acceleration during the test period. Torque sensors are placed at intervals within a set distance from the wheel ends to measure the drive shaft torque during the test period. The set intervals can be adjusted based on actual conditions; preferably, they are one to two centimeters. A speed sensor is placed on the rim end of the drive shaft near the tire under test to measure the wheel speed during the test period.

[0041] S30: Process the vehicle acceleration and wheel speed during the test period to obtain the vehicle speed and wheel acceleration during the test period.

[0042] Specifically, the test of the longitudinal slip characteristic curve of the tire mainly involves the low-frequency signal field. In order to filter out the influence of the engine, road surface and other factors on the accuracy of the test results, it is necessary to perform low-pass filtering on the measured vehicle acceleration, wheel speed and drive shaft torque. By setting a critical frequency, signals above the set critical frequency are blocked and attenuated, while signals below the set critical frequency pass normally. This embodiment mainly analyzes signals within 0-20Hz. Therefore, by using low-pass filtering, signals above 20Hz are blocked and attenuated, eliminating the influence of the engine, road surface and other factors.

[0043] Then, the filtered vehicle acceleration is integrated to obtain the vehicle speed during the test period, and the filtered wheel speed is differentiated to obtain the wheel acceleration during the test period.

[0044] S40: Based on the wheel speed, vehicle speed and radius of the tire under test during the test period, and combined with the first relationship model between the tire slip ratio and the wheel speed and vehicle speed, the slip ratio of the tire under test during the test period is calculated.

[0045] Among them, slip ratio characterizes the degree of longitudinal slippage of the tire, which generates longitudinal force. Based on this, the first relationship model characterizing tire slip ratio can be obtained:

[0046]

[0047] Where μ is the slip ratio. For wheel speed, R is the vehicle speed and R is the tire radius. By substituting the wheel speed, vehicle speed and the radius of the tire measured during the test period into the first relationship model that characterizes the tire slip ratio, the slip ratio of the tire under test during the test period can be calculated.

[0048] S50: Based on the drive shaft torque, wheel acceleration, radius of the tire under test, and tire inertia during the test period, and combined with the second relationship model between the longitudinal force of the tire and the drive shaft torque and wheel acceleration, the longitudinal force of the tire under test during the test period is calculated.

[0049] In this context, longitudinal force refers to the force generated by the driving and braking forces produced by the vehicle's engine and friction with the ground, causing the vehicle to move forward or backward. When the vehicle is in a state of acceleration, a system of differential equations of motion can be established:

[0050]

[0051] Where f is the longitudinal force, J1 is the drive shaft inertia, J2 is the tire inertia (including rim, brake disc, etc.), K is the drive shaft stiffness, C is the drive shaft damping, M is the vehicle mass, θ1 is the angular displacement of the drive shaft, θ2 is the angular displacement of the tire, x is the vehicle displacement, and R is the tire radius. By combining the differential equations, a second relational model characterizing the tire longitudinal force can be obtained:

[0052]

[0053] By substituting the drive shaft torque, wheel acceleration, tire inertia, and radius of the tire under test measured during the test period into the second relational model characterizing the longitudinal force of the tire, the longitudinal force of the tire under test during the test period can be calculated.

[0054] S60: Determine the longitudinal slip characteristic curve of the tire under test based on the slip ratio and longitudinal force of the tire under test during the test period.

[0055] By using the first relationship model between tire slip ratio and wheel speed and vehicle speed, and the second relationship model between tire longitudinal force and drive axle torque and wheel acceleration, the slip ratio and longitudinal force of the tire under test during the test period can be calculated. The characteristic curve μ-t of slip ratio versus time can then be plotted, as shown in the attached figure. Figure 7 As shown in the attached figure, the characteristic curve ft of longitudinal force versus time is... Figure 8 As shown in the attached figure, by selecting the slip ratio and longitudinal force at the same time, the longitudinal slip characteristic curve f-μ of the tire can be plotted. Figure 9 As shown.

[0056] In this embodiment, the vehicle is tested under acceleration. Based on the first relationship model between tire slip ratio and wheel speed and vehicle speed, and the second relationship model between tire longitudinal force and drive axle torque and wheel acceleration, the slip ratio and longitudinal force of the tire under test during the test period are calculated respectively. Combined with the measured tire slip ratio and longitudinal force, the longitudinal slip characteristic curve of the tire under test is determined. Compared with existing tire longitudinal slip characteristic curve testing using tire test benches, this embodiment uses existing equipment for testing, incurring no additional costs and significantly reducing testing costs. Furthermore, the method for obtaining tire longitudinal force in this embodiment is simple to operate, requiring a shorter testing cycle. Since this embodiment tests tire longitudinal force characteristics under full vehicle conditions, the test results have a smaller error compared to the actual vehicle conditions, better reflecting the tire characteristics during actual vehicle operation, which is beneficial for the development and control of the entire vehicle.

[0057] In one embodiment, in step S50, the second relationship model between the longitudinal force of the tire and the drive axle torque and wheel acceleration can also be:

[0058] In the second relationship model characterizing the longitudinal force of the tire: Since the moment of inertia of the drive shaft is much smaller than that of the tires, the difference in angular velocity is relatively small, i.e., J1∝J2. but If we can disregard this, then the second relationship model characterizing the longitudinal force of the tire can also be written as:

[0059]

[0060] Given T d , With J2 and R, the longitudinal force of the tire under test can be calculated.

[0061] In this embodiment, by simplifying the parameters of the second relational model representing the longitudinal force of the tire, another expression of the second relational model representing the longitudinal force of the tire is obtained. This simplified second relational model requires fewer parameters to calculate the longitudinal force of the tire under test, which simplifies the calculation steps and improves the calculation efficiency.

[0062] In one embodiment, in step S20, the vehicle containing the tire to be tested is controlled to be in an accelerated state for testing, and the vehicle acceleration during the test period is obtained as follows:

[0063] By arranging vibration sensors at the steering knuckles of the vehicle, the vehicle acceleration during the test period is detected using the vibration sensors.

[0064] Specifically, the vibration acceleration of the entire vehicle is measured during the test period by placing vibration sensors close to the tires. For example, a piezoelectric accelerometer can be used to measure the vehicle's acceleration. By fixing the piezoelectric accelerometer close to the tires, the force on the sensor changes when the vehicle vibrates, utilizing the piezoelectric effect of piezoelectric ceramics or quartz crystals. According to Newton's second law, when the frequency of the measured vibration is much lower than the natural frequency of the piezoelectric accelerometer, the change in force is proportional to the measured acceleration. Based on this, the vehicle's acceleration can be measured using a piezoelectric accelerometer.

[0065] In this embodiment, to improve accuracy, vibration sensors are placed close to the tire to measure the vehicle acceleration. This provides real-time test parameters for calculating the slip ratio in the first relationship model of the tire longitudinal slip characteristic curve test method, making the slip ratio calculation results more consistent with the actual vehicle conditions.

[0066] In one embodiment, in step S20, the vehicle containing the tire to be tested is controlled to be in an accelerated state for testing, and the wheel speed during the test period is obtained by:

[0067] By arranging a speed sensor on the drive shaft of the tire under test, with the speed sensor spaced within a set distance from the rim end of the tire under test, the wheel speed during the test period is detected by the speed sensor.

[0068] Specifically, wheel speed can be measured during a test period by arranging speed sensors at intervals within a set distance from the rim end of the tire under test. The set interval can be adjusted according to actual conditions; preferably, it can be one to two centimeters. For example, when testing wheel speed, an electromagnetic induction speed sensor can be used. The sensor is arranged at intervals within a set distance from the rim end of the tire under test. When the wheel rotates, the sensor's gears are correspondingly driven to rotate. Based on the principle of magnetism generating electricity, an alternating voltage is generated in the coil around the magnet in the sensor. The frequency of this alternating voltage is proportional to the wheel speed. Therefore, the generated alternating voltage is used as an input signal, which, after shaping and amplification, represents the wheel speed.

[0069] In this embodiment, by arranging speed sensors at intervals within a set distance from the rim end of the tire under test, the wheel speed is measured during the test period. This provides real-time test parameters for calculating the slip ratio in the first relational model of the tire longitudinal slip characteristic curve test method, making the slip ratio calculation result more consistent with the actual vehicle condition.

[0070] In one embodiment, such as Figure 3 As shown, in step S20, the vehicle containing the tire to be tested is controlled to be in an accelerated state for testing, and the drive shaft torque during the test period is obtained, including the following steps:

[0071] S21: The torque strain signal of the drive shaft is measured during the test period by placing a torque sensor on the drive shaft of the tire under test.

[0072] Specifically, to improve testing accuracy, a torque sensor is positioned close to the wheel end. This torque sensor includes an elastic strain gauge, which is a component made of a sensitive grid or similar material used to measure strain. When the torque sensor on the drive shaft is subjected to torque, the elastic strain gauge deforms. This deformation causes the strain gauge to output a slightly varying voltage signal, which is proportional to the magnitude of the torque, thus representing the acquired torque strain signal.

[0073] S22: The acquired torque strain signal is converted into a frequency signal by a voltage-to-frequency converter.

[0074] To enhance the anti-interference capability of the output voltage signal and facilitate long-distance transmission, a voltage-to-frequency converter is needed to convert it into a frequency signal. This is achieved through a circuit that generates an oscillation frequency, namely a varistor. When a changing voltage is input, the capacitance of the varistor changes accordingly, and the changing capacitance causes a change in the oscillation frequency, thus generating a frequency converter. This ensures that the output frequency is proportional to the voltage, thereby completing the voltage-to-frequency conversion.

[0075] S23: Perform carrier modulation processing on the converted frequency signal to obtain a modulated high-frequency composite signal.

[0076] In order to enable better transmission and processing of frequency signals, it is necessary to perform carrier modulation processing on the converted frequency signals, and superimpose the frequency signals with high-frequency carrier signals to form new high-frequency composite signals.

[0077] S24: The modulated high-frequency composite signal is separated by a demodulator to obtain the drive shaft torque during the test period.

[0078] The modulated high-frequency composite signal is transmitted wirelessly. At the receiving end, the demodulator separates the high-frequency composite signal into torque information signal and carrier signal. The separated torque information signal is then transmitted to the data acquisition system for real-time monitoring and recording of torque.

[0079] In this embodiment, with the vehicle containing the tire under test accelerating, a torque sensor is placed on the drive shaft of the tire under test to measure the torque of the drive shaft during the test period. The torque signal collected by the torque sensor is processed by a voltage-to-frequency converter and carrier modulation to be converted into a high-quality high-frequency composite signal for transmission. The converted high-frequency composite signal is transmitted wirelessly to the data acquisition system, thereby realizing real-time monitoring and recording of the drive shaft torque. Through the above steps, the torque of the drive shaft is monitored and recorded in real time while the vehicle is accelerating and the drive shaft is moving at high speed. This provides high-quality test parameters in real time for calculating the second relationship model of the longitudinal force of the tire under test during the test period, making the test results more consistent with the actual vehicle conditions. Moreover, the testing equipment is simple and easy to operate.

[0080] In one embodiment, such as Figure 4 As shown, in step S30, the vehicle acceleration and wheel speed during the test time period are processed to obtain the vehicle speed and wheel acceleration during the test time period, including the following steps:

[0081] S31: Integrate the vehicle acceleration during the test period to obtain the vehicle speed during the test period.

[0082] Specifically, acceleration represents the rate of change of velocity. Therefore, by integrating the vehicle acceleration during the test period, the vehicle speed during the test period can be obtained.

[0083] S32: Differentiate the wheel rotation speed during the test period to obtain the wheel acceleration during the test period.

[0084] Specifically, acceleration represents the rate of change of velocity. Therefore, by differentiating the wheel rotation speed during the test period, the wheel acceleration during the test period can be obtained.

[0085] In this embodiment, by integrating the vehicle acceleration during the test period and differentiating the wheel speed, the vehicle speed and wheel acceleration during the test period are obtained, respectively, providing test parameters for the first relationship model for calculating the slip ratio and the second relationship model for calculating the longitudinal force.

[0086] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0087] In one embodiment, a testing apparatus for a tire longitudinal slip characteristic curve is provided, which corresponds one-to-one with the testing method for the tire longitudinal slip characteristic curve in the above embodiments. For example... Figure 5 As shown, the testing device for the longitudinal slip characteristic curve of the tire includes a relational model parameter acquisition module 51, a test parameter acquisition module 52, a test parameter processing module 53, a slip ratio calculation module 54, a longitudinal force calculation module 55, and a characteristic curve generation module 56. Detailed descriptions of each functional module are as follows:

[0088] The relational model parameter acquisition module 51 is used to acquire the radius and tire inertia of the tire to be tested.

[0089] The test parameter acquisition module 52 is used to control the whole vehicle containing the test tire to be in an accelerated state to obtain the whole vehicle acceleration, wheel speed and drive shaft torque during the test period.

[0090] The test parameter processing module 53 is used to process the vehicle acceleration and wheel speed during the test time period to obtain the vehicle speed and wheel acceleration during the test time period.

[0091] The slip ratio calculation module 54 is used to calculate the slip ratio of the tire under test during the test period based on the wheel speed, vehicle speed and radius of the tire under test during the test period, combined with the first relationship model between the tire slip ratio and the wheel speed and vehicle speed.

[0092] The longitudinal force calculation module 55 is used to calculate the longitudinal force of the tire under test during the test period based on the drive shaft torque, wheel acceleration, radius of the tire under test, and tire inertia during the test period, combined with the second relationship model between the longitudinal force of the tire and the drive shaft torque and wheel acceleration.

[0093] The characteristic curve generation module 56 is used to determine the longitudinal slip characteristic curve of the tire under test based on the slip ratio and longitudinal force of the tire under test during the test time period.

[0094] The slip ratio calculation module 54 mentioned above also includes:

[0095] The first calculation module is used to calculate the first relational model, using the following formula: Where μ is the slip ratio. For wheel speed, R represents the vehicle speed, and R represents the tire radius.

[0096] The aforementioned longitudinal force calculation module 55 also includes:

[0097] The second calculation module is used to calculate the second relational model, using the following formula: Where f is the longitudinal force, T d J1 represents the drive shaft torque, and J2 represents the tire inertia (including rim, brake disc, etc.). R is the wheel acceleration, and R is the tire radius.

[0098] The aforementioned test parameter acquisition module 52 also includes:

[0099] A vibration sensor is used to detect the vehicle acceleration during the test period by means of placing vibration sensors at the steering knuckles of the vehicle.

[0100] The aforementioned test parameter acquisition module 52 also includes:

[0101] A speed sensor is used to detect the wheel speed during the test period by means of arranging the speed sensor on the drive shaft of the tire under test.

[0102] The aforementioned test parameter acquisition module 52 also includes:

[0103] A torque sensor is used to measure the torque strain signal of the drive shaft during the test period by placing the torque sensor on the drive shaft of the tire under test.

[0104] The voltage-frequency conversion module is used to convert the acquired torque strain signal into a frequency signal through a voltage-frequency converter.

[0105] The carrier modulation processing module is used to perform carrier modulation processing on the converted frequency signal to obtain a modulated high-frequency composite signal.

[0106] The drive shaft torque acquisition module is used to separate the modulated high-frequency composite signal through a demodulator to obtain the drive shaft torque within the test time period.

[0107] The aforementioned test parameter processing module 53 also includes:

[0108] An integral processing module is used to integrate the vehicle acceleration during the test time period to obtain the vehicle speed during the test time period.

[0109] The differential processing module is used to perform differential processing on the wheel rotation speed during the test time period to obtain the wheel acceleration during the test time period.

[0110] Specific limitations regarding the testing apparatus for tire longitudinal slip characteristic curves can be found in the limitations of the testing method for tire longitudinal slip characteristic curves described above, and will not be repeated here. Each module in the aforementioned testing apparatus for tire longitudinal slip characteristic curves can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device in hardware form, or stored in the memory of a computer device in software form, so that the processor can call and execute the corresponding operations of each module.

[0111] Figure 6 This is a schematic diagram of the structure of a terminal device provided in Embodiment 4 of the present invention. Figure 6 As shown, the terminal device of this embodiment includes: at least one processor ( Figure 6 Only one is shown in the diagram), a memory, and a computer program stored in the memory and executable on at least one processor, which, when executed by the processor, implements the steps in any of the above-described health prediction method embodiments.

[0112] The terminal device may include, but is not limited to, a processor and memory. Those skilled in the art will understand that... Figure 6 This is merely an example of a terminal device and does not constitute a limitation on the terminal device. A terminal device may include more or fewer components than shown in the figure, or a combination of certain components, or different components, such as network interfaces, displays, and input devices.

[0113] The processor referred to can be a CPU, but it can also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0114] The memory includes readable storage media, internal memory, etc., wherein the internal memory can be the main memory of the terminal device, and the internal memory provides an environment for the operation of the operating system and computer-readable instructions stored in the readable storage media. The readable storage media can be the hard drive of the terminal device, or in some embodiments, it can be an external storage device of the terminal device, such as a plug-in hard drive, a Smart Media Card (SMC), a Secure Digital Card (SD), or a Flash Card. Furthermore, the memory can include both internal storage units and external storage devices of the terminal device. The memory is used to store the operating system, applications, bootloader, data, and other programs, such as program code for computer programs. The memory can also be used to temporarily store data that has been output or will be output.

[0115] Those skilled in the art will understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is used as an example. In practical applications, the functions described above can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments 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. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this invention. The specific working process of the units and modules in the above device can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here. If the integrated unit 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 present invention can implement all or part of the processes in the methods of the above embodiments by instructing related hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the above method embodiments. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. A computer-readable medium can include at least: any entity or device capable of carrying computer program code, a recording medium, a computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media. Examples include USB flash drives, portable hard drives, magnetic disks, or optical disks. In some jurisdictions, according to legislation and patent practice, computer-readable media cannot be electrical carrier signals or telecommunication signals.

[0116] The present invention can implement all or part of the processes in the above embodiments of the method, or it can be accomplished by a computer program product. When the computer program product is run on a terminal device, the terminal device executes the steps in the above method embodiments.

[0117] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0118] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0119] In the embodiments provided by this invention, it should be understood that the disclosed apparatus / terminal devices and methods can be implemented in other ways. For example, the apparatus / terminal device embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and 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 through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0120] 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.

[0121] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for testing the longitudinal slip characteristic curve of a tire, characterized in that, The test method for the tire longitudinal slip characteristic curve includes the following steps: Obtain the radius and inertia of the tire to be tested; The vehicle containing the tire to be tested is controlled to be under acceleration and tested to obtain the vehicle acceleration, wheel speed and drive shaft torque during the test period. The vehicle acceleration and wheel speed during the test period are processed to obtain the vehicle speed and wheel acceleration during the test period. Based on the wheel speed, vehicle speed and radius of the tire under test during the test period, and combined with the first relationship model between the tire slip ratio and the wheel speed and vehicle speed, the slip ratio of the tire under test during the test period is calculated. Based on the drive shaft torque, wheel acceleration, radius of the tire under test, and tire inertia during the test period, and combined with the second relationship model between the longitudinal force of the tire and the drive shaft torque and wheel acceleration, the longitudinal force of the tire under test during the test period is calculated. Based on the slip ratio and longitudinal force of the tire under test during the test period, determine the longitudinal slip characteristic curve of the tire under test; The process of processing the vehicle acceleration and wheel speed during the test period to obtain the vehicle speed and wheel acceleration during the test period includes: The vehicle acceleration during the test period is subjected to low-pass filtering to obtain the filtered vehicle acceleration. The filtered vehicle acceleration is then integrated to obtain the vehicle speed during the test period. The wheel speed during the test period is subjected to low-pass filtering to obtain the filtered wheel speed. The filtered wheel speed is then differentiated to obtain the wheel acceleration during the test period. When the vehicle is accelerating, establish the following system of differential equations of motion: By combining the aforementioned system of differential equations of motion, the second relational model is obtained: in, For longitudinal force, For the drive shaft inertia, For tire inertia, For drive shaft stiffness, For drive shaft damping, For the overall vehicle quality, This represents the angular displacement of the drive shaft. This represents the angular displacement of the tire. For the displacement of the entire vehicle, For the tire radius, This refers to the torque of the drive shaft.

2. The test method for the longitudinal slip characteristic curve of a tire as described in claim 1, characterized in that, The calculation formula for the first relational model is as follows: in, For slip ratio, For wheel speed, For the total vehicle speed, This is the tire radius.

3. The test method for the longitudinal slip characteristic curve of a tire as described in claim 1, characterized in that, The test method for the tire longitudinal slip characteristic curve also includes: By arranging vibration sensors at the steering knuckles of the vehicle, the vehicle acceleration during the test period is detected using the vibration sensors.

4. The test method for the longitudinal slip characteristic curve of a tire as described in claim 1, characterized in that, The test method for the tire longitudinal slip characteristic curve also includes: By arranging a speed sensor on the drive shaft of the tire under test, with the speed sensor spaced within a set distance from the rim end of the tire under test, the wheel speed during the test period is detected by the speed sensor.

5. The test method for the longitudinal slip characteristic curve of a tire as described in claim 1, characterized in that, The test method for the tire longitudinal slip characteristic curve also includes: The torque strain signal of the drive shaft is measured during the test period by placing a torque sensor on the drive shaft of the tire under test. The acquired torque strain signal is converted into a frequency signal using a voltage-to-frequency converter; The converted frequency signal is subjected to carrier modulation processing to obtain a modulated high-frequency composite signal; The modulated high-frequency composite signal is separated by a demodulator to obtain the drive shaft torque during the test period.

6. A testing device for the longitudinal slip characteristic curve of a tire, characterized in that, include: The relational model parameter acquisition module is used to obtain the radius and tire inertia of the tire under test; The test parameter acquisition module is used to control the whole vehicle containing the test tire to be in an accelerated state to obtain the vehicle acceleration, wheel speed and drive shaft torque during the test period. The test parameter processing module is used to process the vehicle acceleration and wheel speed during the test time period to obtain the vehicle speed and wheel acceleration during the test time period. The slip ratio calculation module is used to calculate the slip ratio of the tire under test during the test period based on the wheel speed, vehicle speed and radius of the tire under test during the test period, combined with the first relationship model between the tire slip ratio and the wheel speed and vehicle speed. The longitudinal force calculation module is used to calculate the longitudinal force of the tire under test during the test period based on the drive shaft torque, wheel acceleration, radius of the tire under test, and tire inertia during the test period, combined with the second relationship model between the longitudinal force of the tire and the drive shaft torque and wheel acceleration. The characteristic curve generation module is used to determine the longitudinal slip characteristic curve of the tire under test based on the slip ratio and longitudinal force of the tire under test during the test time period. The test parameter processing module includes: The integral processing module is used to perform low-pass filtering on the vehicle acceleration during the test time period to obtain the filtered vehicle acceleration, and to perform integral processing on the filtered vehicle acceleration to obtain the vehicle speed during the test time period. The differential processing module is used to perform low-pass filtering on the wheel speed during the test time period to obtain the filtered wheel speed, and to perform differential processing on the filtered wheel speed to obtain the wheel acceleration during the test time period. The longitudinal force calculation module includes: When the vehicle is accelerating, establish the following system of differential equations of motion: By combining the aforementioned system of differential equations of motion, the second relational model is obtained: in, For longitudinal force, For the drive shaft inertia, For tire inertia, For drive shaft stiffness, For drive shaft damping, For the overall vehicle quality, This represents the angular displacement of the drive shaft. This represents the angular displacement of the tire. For the displacement of the entire vehicle, For the tire radius, This refers to the torque of the drive shaft.

7. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the test method for the longitudinal slip characteristic curve of a tire as described in any one of claims 1 to 5.

8. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the test method for the longitudinal slip characteristic curve of a tire as described in any one of claims 1 to 5.

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