Tire longitudinal slip characteristic curve testing method, device, equipment and medium

Abstract

The invention discloses a method, a device and equipment for testing a longitudinal slippage characteristic curve of a tire and a medium. The method for testing the longitudinal slippage characteristic curve of the tire comprises the following steps: acquiring the radius and the inertia of the tire to be tested; controlling the whole vehicle containing the to-be-tested tire to be tested in an acceleration state, and obtaining the acceleration of the whole vehicle, the rotating speed of wheels and the torque of a driving shaft; the whole vehicle acceleration and the wheel rotation speed in the test time period are processed respectively, and the whole vehicle speed and the wheel acceleration are obtained; according to the first relation model, the slip rate of the to-be-tested tire is calculated; according to the second relation model, the longitudinal force of the to-be-tested tire is obtained through calculation; and determining a longitudinal slip characteristic curve of the to-be-tested tire according to the slip rate and the longitudinal force of the to-be-tested tire. According to the method, the test cost is reduced, the test period is shortened, and the test result conforms to the real vehicle characteristics.

Description

Technical Field

[0001] The invention relates to the field of vehicle testing, and in particular to a method, device, equipment and medium for testing a tire longitudinal slip characteristic curve. Background Art

[0002] In the prior art, when selecting tires, tire dynamics modeling, and vehicle dynamics simulation analysis, the longitudinal slip characteristic curve of the tire is usually required as input, so as to improve the accuracy of vehicle modeling simulation, thereby providing users with a better driving experience in different driving environments. The existing tire longitudinal slip characteristic curve test method is mainly tested on a tire test bench. Its main principle is to load on a drum dynamometer, and simultaneously measure the rotation and translation speed of the tire and the torque of the drum dynamometer, so as to obtain the longitudinal force slip rate curve of the tire. The test equipment of this method is expensive, and usually requires a specific supplier to test. The test cycle is long, and a high cost is required. In addition, the test results of the tire test bench are far different from the actual vehicle state, which has a great impact on the accuracy of dynamic modeling and vehicle simulation analysis. Summary of the invention

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

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

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

[0006] Controlling the whole vehicle containing the tire to be tested to be in an accelerated state for testing, and obtaining the whole vehicle acceleration, wheel speed and drive shaft torque within the test period;

[0007] The vehicle acceleration and wheel speed within the test period are processed respectively to obtain the vehicle speed and wheel acceleration within the test period;

[0008] The slip rate of the tire to be tested within the test time period is calculated based on the wheel speed, the vehicle speed and the radius of the tire to be tested within the test time period and in combination with a first relationship model between the tire slip rate and the wheel speed and the vehicle speed;

[0009] The longitudinal force of the tire to be tested within the test time period is calculated based on the drive shaft torque, wheel acceleration, radius of the tire to be tested and tire inertia within the test time period, and a second relationship model between the longitudinal force of the tire and the drive shaft torque and wheel acceleration;

[0010] A longitudinal slip characteristic curve of the tire to be tested is determined according to the slip rate and the longitudinal force of the tire to be tested within the test time period.

[0011] In a second aspect, an embodiment of the present invention provides a device for testing a tire longitudinal slip characteristic curve, the device comprising:

[0012] A relational model parameter acquisition module is used to obtain the radius and tire inertia of the tire to be tested;

[0013] A test parameter acquisition module, used to obtain the acceleration of the whole vehicle, the wheel speed and the drive shaft torque within the test period by controlling the whole vehicle containing the tire to be tested to be in an accelerated state for testing;

[0014] A test parameter processing module, used to process the vehicle acceleration and wheel speed in the test time period respectively to obtain the vehicle speed and wheel acceleration in the test time period;

[0015] a slip rate calculation module, configured to calculate the slip rate of the tire to be tested within the test time period according to the wheel speed, the vehicle speed and the radius of the tire to be tested within the test time period and in combination with a first relationship model between the tire slip rate and the wheel speed and the vehicle speed;

[0016] a longitudinal force calculation module, configured to calculate the longitudinal force of the tire to be tested within the test time period according to the drive shaft torque, the wheel acceleration within the test time period, the radius of the tire to be tested and the tire inertia, and a second relationship model between the longitudinal force of the tire and the drive shaft torque and the wheel acceleration;

[0017] The characteristic curve generating module is used to determine the longitudinal slip characteristic curve of the tire to be tested according to the slip rate and longitudinal force of the tire to be tested within the test time period.

[0018] In a third aspect, an embodiment of the present invention provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-mentioned tire longitudinal slip characteristic curve testing method when executing the computer program.

[0019] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above-mentioned tire longitudinal slip characteristic curve testing method are implemented.

[0020] In a fifth aspect, an embodiment of the present invention provides a computer program product. When the computer program product is run on a terminal device, the terminal device executes the steps of the above-mentioned tire longitudinal slip characteristic curve testing method.

[0021] The above-mentioned tire longitudinal slip characteristic curve testing method, device, equipment and medium control the whole vehicle to be tested in an accelerated state, and calculate the slip rate and longitudinal force of the tire to be tested during the test time period based on a first relationship model between the tire slip rate and the wheel speed and the whole vehicle speed, and a second relationship model between the tire longitudinal force and the drive shaft torque and the wheel acceleration, and determine the longitudinal slip characteristic curve of the tire to be tested in combination with the measured tire slip rate and longitudinal force.

[0022] Through the above steps, compared with the existing tire longitudinal slip characteristic curve test through a tire test bench, the present invention is based on existing equipment for testing, without additional costs, which greatly saves testing costs. At the same time, the method for obtaining the tire longitudinal force of the present invention is simple to operate, so the required test cycle is short, and the present invention tests the tire longitudinal force characteristics based on the whole vehicle state, the error between the test result and the actual vehicle state is small, and it can better reflect the tire characteristics when the actual vehicle is running, which is beneficial to the development and control of the whole vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

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

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

[0026] Figure 3 is a flow chart of obtaining the drive shaft torque in a method for testing a tire longitudinal slip characteristic curve in one embodiment of the present invention;

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

[0028] Figure 5 It is a principle block diagram of a testing device for a tire longitudinal slip characteristic curve in one embodiment of the present invention;

[0029] Figure 6 is a schematic diagram of a computer device in one embodiment of the present invention;

[0030] Figure 7 is a characteristic curve of slip rate and time in a method for testing a tire longitudinal slip characteristic curve in one embodiment of the present invention;

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

[0032] Fig. 9 is a tire longitudinal slip characteristic curve in one embodiment of the present invention. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] The tire longitudinal slip characteristic curve testing method provided in this application can be applied to Figure 1 In an application environment, a client (computer device) communicates with a server through a network. The client obtains a test request for a tire longitudinal slip characteristic curve, and sends the test request for the tire longitudinal slip characteristic curve to a server. After the server obtains the test request for the tire longitudinal slip characteristic curve, it performs corresponding processing based on the test request for the tire longitudinal slip characteristic curve, and responds to the test request for the tire longitudinal slip characteristic curve. Among them, the computer device can be but is not limited to various personal computers, laptops, smart phones, tablet computers, and portable wearable devices. The server can be implemented with an independent server or a server cluster consisting of multiple servers.

[0035] In one embodiment, if Figure 2 As shown, a method for testing the longitudinal slip characteristic curve of a tire is provided. The method is applied in Figure 1 The server in the example is used as an example to illustrate the following steps:

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

[0037] The radius of the tire to be tested is usually calculated according to the tire load formula. First, the load factor of the tire to be tested is obtained through the relevant technical manuals provided by the tire manufacturer. The load factor is a factor related to the tire size and structure. Secondly, the load of the tire to be tested is calculated based on factors such as the total weight of the vehicle, the axle load distribution, and the tire load distribution coefficient. Finally, the radius of the tire to be tested can be calculated according to the tire load formula: tire radius = load / load factor.

[0038] The inertia of rotating parts such as tires, rims, and fixed discs are obtained by means of experiments or simulations, and the obtained inertia of rotating parts such as tires, rims, and fixed discs are added together to obtain the total inertia, which is the tire inertia.

[0039] S20: Controlling the whole vehicle including the tire to be tested to be in an accelerated state for testing, and obtaining the whole vehicle acceleration, wheel speed and drive shaft torque within the test period.

[0040] In order to make the test results consistent with the actual vehicle characteristics, the whole vehicle containing the tire to be tested is controlled to be in an accelerated state for testing, and the acceleration of the whole vehicle is measured during the test period by arranging a vibration sensor at a position within a set distance from the tire, and the torque of the drive shaft is measured during the test period by arranging a torque sensor at a position within a set distance from the wheel end, wherein the size of the set distance can be adjusted according to actual conditions, preferably, the set distance can be one to two centimeters. The wheel speed is measured during the test period by arranging a speed sensor at the rim end of the drive shaft close to the tire to be tested.

[0041] S30: Processing the vehicle acceleration and wheel speed within the test time period respectively to obtain the vehicle speed and wheel acceleration within the test time period.

[0042] Specifically, the test of the tire longitudinal slip characteristic curve mainly involves the field of low-frequency signals. In order to filter out the influence of the engine, road surface, etc. 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 the critical frequency, signals with a frequency higher than the set critical frequency are blocked and weakened, and signals with a frequency lower than the set critical frequency are passed normally. This embodiment mainly analyzes signals within 0-20Hz, so through low-pass filtering, signals higher than 20Hz are blocked and attenuated, eliminating the influence of the engine, road surface, etc.

[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: Calculate the slip rate of the tire to be tested within the test time period according to the wheel speed, the vehicle speed and the radius of the tire to be tested within the test time period and in combination with a first relationship model between the tire slip rate and the wheel speed and the vehicle speed.

[0045] Among them, the slip rate represents the degree of longitudinal slip of the tire, which will generate longitudinal force. Based on this, the first relationship model representing the tire slip rate can be obtained:

[0046]

[0047] Where μ is the slip ratio, is the wheel speed, is the vehicle speed, R is the radius of the tire, and the wheel speed, vehicle speed and radius of the tire to be tested measured within the test time period are substituted into the first relationship model characterizing the tire slip rate, so as to calculate the slip rate of the tire to be tested within the test time period.

[0048] S50: Calculate the longitudinal force of the tire to be tested within the test time period based on the drive shaft torque, wheel acceleration, radius of the tire to be tested and tire inertia within the test time period and a second relationship model between the longitudinal force of the tire and the drive shaft torque and wheel acceleration.

[0049] Among them, the longitudinal force refers to the force generated by the driving force generated by the vehicle engine and the braking force and the friction with the ground that makes the vehicle move forward and backward. When the whole vehicle is in a state of acceleration, the motion differential equation group can be established:

[0050]

[0051] Among them, f is the longitudinal force, J1 is the drive shaft inertia, J2 is the tire inertia (including rims, brake discs, 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, the second relationship model that characterizes the tire longitudinal force can be obtained:

[0052]

[0053] The drive shaft torque, wheel acceleration, tire inertia and radius of the tire to be tested measured during the test period are substituted into the second relationship model representing the longitudinal force of the tire, so that the longitudinal force of the tire to be tested during the test period can be calculated.

[0054] S60: Determine a longitudinal slip characteristic curve of the tire to be tested according to the slip rate and the longitudinal force of the tire to be tested within the test time period.

[0055] Through the first relationship model between the tire slip rate and the wheel speed and the vehicle speed and the second relationship model between the tire longitudinal force and the drive shaft torque and the wheel acceleration, the slip rate and longitudinal force of the tire to be tested during the test period can be calculated, and the characteristic curves μ-t of the slip rate and time can be drawn respectively, as shown in the attached figure. Figure 7 As shown in the figure, the characteristic curve of longitudinal force and time ft is shown in the figure. Figure 8 By selecting the slip rate and longitudinal force at the same time, the tire longitudinal slip characteristic curve f-μ can be drawn, as shown in the attached figure. Fig. 9 shown.

[0056] In this embodiment, by controlling the whole vehicle to be tested in an accelerated state, the slip rate and longitudinal force of the tire to be tested in the test time period are calculated respectively according to the first relationship model between the tire slip rate and the wheel speed and the whole vehicle speed, and the second relationship model between the longitudinal force of the tire and the drive shaft torque and the wheel acceleration, and the longitudinal slip characteristic curve of the tire to be tested is determined in combination with the measured tire slip rate and longitudinal force. Through the above steps, compared with the existing tire longitudinal slip characteristic curve test through a tire test bench, this embodiment is based on the existing equipment for testing, there is no additional cost, and the testing cost is greatly saved. At the same time, the method for obtaining the longitudinal force of the tire in this embodiment is simple to operate, so the required test cycle is short, and this embodiment is based on the whole vehicle state to test the longitudinal force characteristics of the tire, the error between the test result and the actual vehicle state is small, and it can better reflect the tire characteristics when the actual vehicle is running, which is beneficial to the development and control of the whole vehicle.

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

[0058] Among them, in the second relationship model representing the longitudinal force of the tire: Since the drive shaft inertia is much smaller than the tire inertia, the angular velocity magnitude difference is small, that is, J1∝J2, but can be ignored, then the second relational model representing the longitudinal force of the tire can also be written as:

[0059]

[0060] In the known T d , In the case of J2 and R, the longitudinal force of the tire to be tested can be calculated.

[0061] In this embodiment, by simplifying the parameters of the second relationship model characterizing the longitudinal force of the tire, another expression form of the second relationship model characterizing the longitudinal force of the tire is obtained. The second relationship model after parameter elimination and simplification requires fewer parameters to calculate the longitudinal force of the tire to be tested, thereby simplifying the calculation steps and improving the calculation efficiency.

[0062] In one embodiment, in step S20, the whole vehicle including the tire to be tested is controlled to be in an accelerated state for testing, and the acceleration of the whole vehicle within the test time period is obtained, which includes:

[0063] A vibration sensor is arranged at the steering knuckle of the whole vehicle, and the acceleration of the whole vehicle within the test time period is detected by using the vibration sensor.

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

[0065] In this embodiment, in order to improve the accuracy, the acceleration of the whole vehicle is measured by arranging a vibration sensor at a place close to the tire, which provides real-time test parameters for calculating the slip rate by the first relationship model in the test method of the tire longitudinal slip characteristic curve, so that the calculation result of the slip rate is more consistent with the actual vehicle state.

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

[0067] A rotation speed sensor is arranged on the driving shaft of the tire to be tested, wherein the rotation speed sensor is spaced within a set distance from the rim end of the tire to be tested, and the wheel rotation speed within the test time period is detected by the rotation speed sensor.

[0068] Specifically, the wheel speed can be measured within the test period by arranging a speed sensor at a distance within a set distance from the rim end of the tire to be tested. The set distance can be set according to actual conditions. Preferably, the set distance can be one to two centimeters. For example, when testing the wheel speed, an electromagnetic induction speed sensor can be used. The electromagnetic induction speed sensor is arranged at a distance within a set distance from the rim end of the tire to be tested. When the wheel rotates, the gear of the sensor is driven to rotate accordingly. According to the principle of magnetoelectricity, an AC voltage will be generated in the coil around the magnet in the sensor, and the frequency of the generated AC voltage is proportional to the wheel speed. Based on this, the generated AC voltage is used as an input signal, and after shaping and amplification, it can represent the wheel speed.

[0069] In this embodiment, by arranging a speed sensor at a distance within a set interval from the rim end of the tire to be tested, the wheel speed is measured during a test period, providing real-time test parameters for calculating the slip rate using the first relationship model in the test method of the tire longitudinal slip characteristic curve, so that the calculation result of the slip rate is more consistent with the actual vehicle state.

[0070] In one embodiment, if Figure 3 As shown, in step S20, the whole vehicle including the tire to be tested is controlled to be in an accelerated state for testing to obtain the drive shaft torque within the test time period, including the following steps:

[0071] S21: Disposing a torque sensor on the driving shaft of the tire to be tested to measure the driving shaft torque strain signal during a test period.

[0072] Specifically, in order to improve the accuracy of the test, a torque sensor is arranged at a position close to the wheel end. The torque sensor includes an elastic element strain gauge, which refers to an element composed of a sensitive grid, etc. for measuring strain. When the torque sensor arranged on the drive shaft is subjected to torque, the elastic element strain gauge will deform. At this time, the strain gauge will output a weakly changing voltage signal with the deformation. The voltage signal is proportional to the torque, which can represent the collected torque strain signal.

[0073] S22: Convert the collected torque strain signal into a frequency signal through a voltage-to-frequency converter.

[0074] In order to make the output voltage signal have stronger anti-interference ability and better carry out long-distance transmission, it is necessary to convert it into a frequency signal through a voltage-frequency converter. By generating a circuit with an oscillation frequency, namely a varistor, when a changing voltage is input, the capacity of the varistor will change accordingly, and the changing capacitance will cause the oscillation frequency to change, resulting in variable frequency, which can ensure that the output frequency is proportional to the voltage, that is, the conversion of voltage and frequency is completed.

[0075] S23: Carrier modulation is performed on the converted frequency signal to obtain a modulated high-frequency composite signal.

[0076] In order to better transmit and process the frequency signal, it is necessary to perform carrier modulation processing on the converted frequency signal, superimpose the frequency signal with the high-frequency carrier signal, and form a new high-frequency composite signal.

[0077] S24: Separate the modulated high-frequency composite signal through a demodulator to obtain the drive shaft torque within the test time period.

[0078] The modulated high-frequency composite signal is transmitted by radio. At the receiving end, the high-frequency composite signal is separated into the torque information signal and the carrier signal through a demodulator, and the separated torque information signal is transmitted to the data acquisition system, thereby monitoring and recording the torque in real time.

[0079] In this embodiment, when the whole vehicle containing the tire to be tested is in an accelerated state, the torque of the drive shaft is measured during the test period by arranging a torque sensor on the drive shaft of the tire to be tested. The torque signal is collected by the torque sensor, and is converted into a high-frequency composite signal for transmission with higher quality after being processed by a voltage-frequency converter and carrier modulation. The converted high-frequency composite signal is transmitted to the data acquisition system by radio, thereby realizing real-time monitoring and recording of the torque of the drive shaft. Through the above steps, when the whole vehicle is in an accelerated state and the drive shaft is in a high-speed motion state, the torque of the drive shaft is monitored and recorded in real time, and high-quality test parameters are provided in real time for calculating the second relationship model of the longitudinal force of the tire to be tested during the test time, so that the test results are more consistent with the actual vehicle state, and the detection equipment is simple and easy to operate.

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

[0081] S31: Integrate the acceleration of the whole vehicle in the test time period to obtain the speed of the whole vehicle in the test time period.

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

[0083] S32: performing differentiation processing on the wheel speed within the test time period to obtain the wheel acceleration within the test time period.

[0084] Specifically, acceleration represents the rate of change of speed, so the wheel acceleration during the test period can be obtained by performing differentiation processing on the wheel speed during the test period.

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

[0086] It should be understood that the order of execution of the steps in the above embodiment does not necessarily mean 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 embodiment of the present invention.

[0087] In one embodiment, a device for testing a tire longitudinal slip characteristic curve is provided, and the device for testing a tire longitudinal slip characteristic curve corresponds to the method for testing a tire longitudinal slip characteristic curve in the above embodiment. Figure 5 As shown, the tire longitudinal slip characteristic curve test device includes a relationship model parameter acquisition module 51, a test parameter acquisition module 52, a test parameter processing module 53, a slip rate calculation module 54, a longitudinal force calculation module 55, and a characteristic curve generation module 56. The functional modules are described in detail as follows:

[0088] The relationship model parameter acquisition module 51 is used to obtain the radius and tire inertia of the tire to be tested;

[0089] A test parameter acquisition module 52 is used to obtain the acceleration of the vehicle, the wheel speed and the drive shaft torque within the test period by controlling the vehicle containing the tire to be tested to be in an accelerated state for testing;

[0090] A test parameter processing module 53 is used to process the vehicle acceleration and wheel speed in the test time period respectively to obtain the vehicle speed and wheel acceleration in the test time period;

[0091] The slip rate calculation module 54 is used to calculate the slip rate of the tire to be tested within the test time period according to the wheel speed, the vehicle speed and the radius of the tire to be tested within the test time period and in combination with a first relationship model between the tire slip rate and the wheel speed and the vehicle speed;

[0092] A longitudinal force calculation module 55 is used to calculate the longitudinal force of the tire to be tested within the test time period according to the drive shaft torque, wheel acceleration within the test time period, the radius of the tire to be tested and the tire inertia, combined with a second relationship model between the longitudinal force of the tire and the drive shaft torque and wheel acceleration;

[0093] The characteristic curve generating module 56 is used to determine the longitudinal slip characteristic curve of the tire to be tested according to the slip rate and longitudinal force of the tire to be tested during the test time period.

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

[0095] The first calculation module is used to calculate the first relationship model, and the formula is as follows: Where μ is the slip ratio, is the wheel speed, is the vehicle speed, and R is the tire radius.

[0096] The longitudinal force calculation module 55 further includes:

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

[0098] The above-mentioned test parameter acquisition module 52 also includes:

[0099] The vibration sensor is used to detect the acceleration of the whole vehicle within the test time period by arranging the vibration sensor at the steering knuckle of the whole vehicle.

[0100] The above-mentioned test parameter acquisition module 52 also includes:

[0101] The rotation speed sensor is used to detect the wheel rotation speed within the test time period by arranging the rotation speed sensor on the drive shaft of the tire to be tested.

[0102] The above-mentioned test parameter acquisition module 52 also includes:

[0103] A torque sensor is used to measure a torque strain signal of the drive shaft during a test period by arranging the torque sensor on the drive shaft of the tire to be tested;

[0104] A voltage-frequency conversion module, used for converting the collected torque strain signal into a frequency signal through a voltage-frequency converter;

[0105] A carrier modulation processing module, used for performing 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 a test period.

[0107] The above-mentioned test parameter processing module 53 also includes:

[0108] An integral processing module, used for integrating the acceleration of the whole vehicle within the test time period to obtain the speed of the whole vehicle within the test time period;

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

[0110] The specific definition of the test device for the tire longitudinal slip characteristic curve can be found in the definition of the test method for the tire longitudinal slip characteristic curve in the above text, and will not be repeated here. Each module in the above-mentioned test device for the tire longitudinal slip characteristic curve can be implemented in whole or in part by software, hardware and a combination thereof. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory in the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[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), a memory, and a computer program stored in the memory and executable on at least one processor, wherein when the processor executes the computer program, the steps in any of the above-mentioned health prediction method embodiments are implemented.

[0112] The terminal device may include, but is not limited to, a processor and a memory. Those skilled in the art will understand that Figure 6 It is only an example of a terminal device and does not constitute a limitation on the terminal device. The terminal device may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, it may also include a network interface, a display screen, and an input device.

[0113] The processor may be a CPU, or other general-purpose processors, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0114] The memory includes a readable storage medium, an internal memory, etc., wherein the internal memory may be the memory of the terminal device, and the internal memory provides an environment for the operation of the operating system and the computer-readable instructions in the readable storage medium. The readable storage medium may be the hard disk of the terminal device, and in other embodiments, it may also be an external storage device of the terminal device, for example, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (SecureDigital, SD) card, a flash card (Flash Card), etc. equipped on the terminal device. Further, the memory may also include both an internal storage unit of the terminal device and an external storage device. The memory is used to store an operating system, an application program, a boot loader (BootLoader), data, and other programs, such as the program code of a computer program, etc. The memory may also be used to temporarily store data that has been output or is to be output.

[0115] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated into a processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of the present invention. The specific working process of the units and modules in the above-mentioned device can refer to the corresponding process in the above-mentioned method embodiment, which will not be repeated here. If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, which can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, the steps of the above-mentioned method embodiment can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may at least include: any entity or device capable of carrying computer program code, recording medium, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium. For example, a USB flash drive, a mobile hard disk, a magnetic disk or an optical disk. In some jurisdictions, according to legislation and patent practice, computer-readable media cannot be electric carrier signals and telecommunication signals.

[0116] The present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by a computer program product. When the computer program product runs on a terminal device, the terminal device can implement the steps in the above-mentioned method embodiment when executing it.

[0117] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0118] Those skilled in the art will appreciate that the units and algorithm steps of each example 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 performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0119] In the embodiments provided by the present invention, it should be understood that the disclosed devices / terminal equipment and methods can be implemented in other ways. For example, the device / terminal equipment embodiments described above are only schematic, for example, the division of modules or units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0120] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0121] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention.

Claims

1. A method for testing a tire longitudinal slip characteristic curve, characterized in that: The tire longitudinal slip characteristic curve testing method comprises the following steps: Get the radius and tire inertia of the tire to be tested; Controlling the whole vehicle containing the tire to be tested to be in an accelerated state for testing, and obtaining the whole vehicle acceleration, wheel speed and drive shaft torque within the test period; The vehicle acceleration and wheel speed within the test period are processed respectively to obtain the vehicle speed and wheel acceleration within the test period; The slip rate of the tire to be tested within the test time period is calculated based on the wheel speed, the vehicle speed and the radius of the tire to be tested within the test time period and in combination with a first relationship model between the tire slip rate and the wheel speed and the vehicle speed; The longitudinal force of the tire to be tested within the test time period is calculated based on the drive shaft torque, wheel acceleration, radius of the tire to be tested and tire inertia within the test time period, and a second relationship model between the longitudinal force of the tire and the drive shaft torque and wheel acceleration; A longitudinal slip characteristic curve of the tire to be tested is determined according to the slip rate and the longitudinal force of the tire to be tested within the test time period.

2. The tire longitudinal slip characteristic curve testing method according to claim 1, characterized in that: The calculation formula of the first relationship model is as follows: Where μ is the slip ratio, is the wheel speed, is the vehicle speed, and R is the tire radius.

3. The tire longitudinal slip characteristic curve testing method according to claim 1, characterized in that: The calculation formula of the second relationship model is as follows: Where f is the longitudinal force, T d is the drive shaft torque, J2 is the tire inertia (including wheel rim, brake disc, etc.), is the wheel acceleration and R is the tire radius.

4. The tire longitudinal slip characteristic curve testing method according to claim 1, characterized in that: The tire longitudinal slip characteristic curve testing method further includes: A vibration sensor is arranged at the steering knuckle of the whole vehicle, and the acceleration of the whole vehicle within the test time period is detected by using the vibration sensor.

5. The tire longitudinal slip characteristic curve testing method according to claim 1, characterized in that: The tire longitudinal slip characteristic curve testing method further includes: A rotation speed sensor is arranged on the driving shaft of the tire to be tested, wherein the rotation speed sensor is spaced within a set distance from the rim end of the tire to be tested, and the wheel rotation speed within the test time period is detected by the rotation speed sensor.

6. The tire longitudinal slip characteristic curve testing method according to claim 1, characterized in that: The tire longitudinal slip characteristic curve testing method further includes: By arranging a torque sensor on the driving shaft of the tire to be tested, the driving shaft torque strain signal is measured during the test period; Converting the collected torque strain signal into a frequency signal through a voltage-to-frequency converter; Carrier modulation is performed on the converted frequency signal 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 within the test period.

7. The tire longitudinal slip characteristic curve testing method according to claim 1, characterized in that: The vehicle acceleration and wheel speed within the test time period are processed respectively to obtain the vehicle speed and wheel acceleration within the test time period, including: Integrating the acceleration of the whole vehicle during the test period to obtain the speed of the whole vehicle during the test period; The wheel speed in the test time period is differentiated to obtain the wheel acceleration in the test time period.

8. A tire longitudinal slip characteristic curve testing device, characterized in that: include: A relational model parameter acquisition module is used to obtain the radius and tire inertia of the tire to be tested; A test parameter acquisition module, used to obtain the acceleration of the whole vehicle, the wheel speed and the drive shaft torque within the test period by controlling the whole vehicle containing the tire to be tested to be in an accelerated state for testing; A test parameter processing module, used to process the vehicle acceleration and wheel speed in the test time period respectively to obtain the vehicle speed and wheel acceleration in the test time period; a slip rate calculation module, configured to calculate the slip rate of the tire to be tested within the test time period according to the wheel speed, the vehicle speed and the radius of the tire to be tested within the test time period and in combination with a first relationship model between the tire slip rate and the wheel speed and the vehicle speed; a longitudinal force calculation module, configured to calculate the longitudinal force of the tire to be tested within the test time period according to the drive shaft torque, the wheel acceleration within the test time period, the radius of the tire to be tested and the tire inertia, and a second relationship model between the longitudinal force of the tire and the drive shaft torque and the wheel acceleration; The characteristic curve generating module is used to determine the longitudinal slip characteristic curve of the tire to be tested according to the slip rate and longitudinal force of the tire to be tested within the test time period.

9. 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, the steps of the method for testing the tire longitudinal slip characteristic curve according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method for testing the tire longitudinal slip characteristic curve as claimed in any one of claims 1 to 7 are implemented.

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