Tire braking performance determination method and device and electronic equipment

Abstract

The invention discloses a tire braking performance determination method and device and electronic equipment. The method comprises the following steps: acquiring a target impression length and a target impression width of a contact area between a tire and the ground when the tire is in static load; determining an association relationship between the water film thickness and the mark length of the tire under the condition of wading braking, and determining a first mark length of the tire under the condition that the water film thickness is zero according to the association relationship; determining a first area of the tire according to the target print length and the target print width, and determining a second area of the tire according to the first print length and the target print width; according to the first area, the second area, the critical speed and the movement speed of the tire, the radial load of the ground contact area of the tire during wading braking is determined; and determining a performance evaluation index of the tire during wading braking according to the radial load, the first print length and the target print width. The technical problems of high cost and low efficiency of a related tire braking performance determination method are solved.

Description

Technical Field

[0001] This application relates to the field of tire braking performance, and more specifically, to a method and apparatus for determining tire braking performance, and electronic equipment. Background Technology

[0002] Tires are the only part of a car that comes into contact with the road surface, and their braking performance determines the safety of driving. The main methods for evaluating tire braking performance are real-vehicle testing and finite element method (FEM) simulation analysis. Real-vehicle testing requires installing the tire on a vehicle after production and conducting actual driving tests on a standard wet road surface. While real-vehicle testing provides data closest to real-world driving conditions, the upfront costs of tire production and subsequent road testing arrangements make the entire testing cycle lengthy and costly. In contrast, FEM technology can predict performance during the tire design phase, eliminating the need for actual tire production and reducing costs and time. However, simulation models for wet braking are complex to build, requiring high computational power, and the accuracy of simulation results is often limited by various factors, including model simplification, parameter settings, and computational resource constraints.

[0003] Both of the above methods have their limitations when evaluating tire wet braking performance. Real vehicle testing is costly and time-consuming, while simulation analysis can be carried out in the design stage, but the models are complex, the computational resources are high, and the accuracy of the results is difficult to guarantee. All of these pose challenges to the efficiency and cost control of tire design and development.

[0004] There is currently no effective solution to the above problems. Summary of the Invention

[0005] This application provides a method, apparatus, and electronic device for determining tire braking performance, to at least solve the technical problems of high cost and low efficiency in related methods for determining tire braking performance.

[0006] According to one aspect of this application, a method for determining tire braking performance is provided, comprising: obtaining the target imprint length and target imprint width of the tire's contact area with the ground under static load; determining the correlation between the tire's water film thickness and imprint length under wading braking conditions, and determining a first imprint length of the tire when the water film thickness is zero based on the correlation; determining a first area of ​​the tire based on the target imprint length and target imprint width, and determining a second area of ​​the tire based on the first imprint length and target imprint width; determining the radial load of the tire's contact area under wading braking based on the first area, the second area, the critical speed of the tire under complete hydroplaning, and the tire's movement speed; and determining a performance evaluation index of the tire under wading braking based on the radial load of the tire's contact area under wading braking, the first imprint length, and the target imprint width.

[0007] Optionally, obtaining the target imprint length and target imprint width of the tire in contact with the ground under static load includes: establishing a two-dimensional simulation model of the tire based on the tire's structural material distribution diagram; performing three-dimensional processing on the two-dimensional simulation model to obtain a three-dimensional simulation model; in the three-dimensional simulation model, applying uniform gas pressure to the inner surface of the tire and applying radial force to the area where the tire contacts the ground to obtain the target imprint length and target imprint width of the tire in contact with the ground under static load.

[0008] Optionally, the relationship between the tire's water film thickness and the imprint length under wading braking conditions is determined, including: determining the relationship based on the target imprint length, target imprint width, tire's static radial force, fluid's dynamic viscosity, tire's speed, and the changes in imprint length and water film thickness during wading braking.

[0009] Optionally, the radial load of the tire's contact area during wading braking is determined based on the first area, the second area, the critical speed of the tire when fully hydroplaned, and the tire's movement speed. This includes: determining the critical speed of the tire when fully hydroplaned based on the tire's average ground pressure, water density, initial water film thickness, ground roughness, tread groove depth, tread porosity, and the number of longitudinal tread grooves; wherein the average ground pressure is the average vertical pressure of the tire's contact area with the ground during wading braking, and the initial water film thickness is the thickness of the water layer on the ground before the tire contacts the ground; and determining the radial load of the tire's contact area during wading braking based on the first area, the second area, the critical speed, and the tire's movement speed.

[0010] Optionally, the radial load of the tire's contact area during wading braking is determined based on the first area, the second area, the critical speed of the tire when fully hydroplaned, and the tire's movement speed, including: determining the radial load of the tire's contact area during wading braking based on the first area, the second area, the critical speed of the tire when fully hydroplaned, the tire's static radial force, the tire's movement speed, and the water flow density.

[0011] Optionally, the performance evaluation index of the tire during wading braking is determined based on the radial load, first imprint length, and target imprint width of the tire's contact area during wading braking. This includes: using a tire braking force solution model to calculate the radial load, first imprint length, and target imprint width of the tire's contact area during wading braking in the first and second regions respectively, to obtain the tire's braking force under different slip ratios, where the first region is the adhesion zone where the tire does not slip, and the second region is the slip zone where the tire slips; determining a target curve based on the tire's braking force under different slip ratios and the tire's static radial force, where the horizontal axis of the target curve represents the slip ratio, and the vertical axis represents the ratio of the tire's braking force to the tire's static radial force; and determining the tire's performance evaluation index during wading braking based on the target curve.

[0012] Optionally, based on the target curve, the performance evaluation index of the tire during wading braking is determined, including: determining the maximum value of the target curve in the vertical direction as the peak friction coefficient; determining the slip ratio corresponding to the peak friction coefficient as the optimal slip ratio; determining the slope of the target curve as the braking stiffness; and determining the descent speed of the target curve after reaching its maximum value as the peak fade rate.

[0013] According to another aspect of this application, a device for determining tire braking performance is also provided, comprising: an acquisition module for acquiring the target imprint length and target imprint width of the tire's contact area with the ground under static load; a first determination module for determining the correlation between the tire's water film thickness and imprint length under wading braking conditions, and determining the first imprint length of the tire when the water film thickness is zero based on the correlation; a second determination module for determining a first area of ​​the tire based on the target imprint length and target imprint width, and determining a second area of ​​the tire based on the first imprint length and target imprint width; a third determination module for determining the radial load of the tire's contact area under wading braking conditions based on the first area, the second area, the critical speed of the tire under complete hydroplaning, and the tire's movement speed; and a fourth determination module for determining the tire's performance evaluation index under wading braking conditions based on the radial load of the tire's contact area under wading braking conditions, the first imprint length, and the target imprint width.

[0014] According to another aspect of this application, a non-volatile storage medium is also provided, the storage medium including a stored program, wherein when the program runs, it controls the device where the storage medium is located to execute the above-mentioned method for determining tire braking performance.

[0015] According to another aspect of this application, an electronic device is also provided, comprising: a memory and a processor, the processor being configured to run a program stored in the memory, wherein the program, when running, executes the above-described method for determining tire braking performance.

[0016] According to another aspect of this application, a computer program is also provided, wherein when the computer program is executed by a processor, it implements the above-mentioned method for determining tire braking performance.

[0017] According to another aspect of this application, a computer program product is also provided, the computer program product including a non-volatile computer-readable storage medium, wherein the non-volatile computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, it implements the above-mentioned method for determining tire braking performance.

[0018] In this application, the following methods are employed: obtaining the target imprint length and target imprint width of the tire's contact area with the ground under static load; determining the correlation between the tire's water film thickness and imprint length under wading braking conditions, and determining the first imprint length of the tire when the water film thickness is zero based on the correlation; determining the first area of ​​the tire based on the target imprint length and target imprint width, and determining the second area of ​​the tire based on the first imprint length and target imprint width; determining the radial load of the tire's contact area under wading braking based on the first area, second area, the tire's critical speed under complete hydroplaning, and the tire's movement speed; and determining the tire's performance evaluation index under wading braking based on the radial load of the tire's contact area under wading braking, the first imprint length, and the target imprint width. This approach achieves the technical effect of simultaneously using finite element analysis and mathematical models to determine the tire's braking performance during the tire design stage, thereby reducing the time and economic costs of tire design and development, and solving the technical problem of high cost and low efficiency in related tire braking performance determination methods. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0020] Figure 1 This is a flowchart of a method for determining tire braking performance according to an embodiment of this application;

[0021] Figure 2 This is a graph showing the relationship between the ratio of braking force to static radial force and slip ratio according to an embodiment of this application;

[0022] Figure 3 This is a schematic diagram of a two-dimensional simulation model of a tire according to an embodiment of this application;

[0023] Figure 4 This is a schematic diagram of a tire ground contact mark according to an embodiment of this application;

[0024] Figure 5This is a graph showing the variation of the thickness of the water film inside the tire contact surface along the length of the imprint, according to an embodiment of this application.

[0025] Figure 6 This is a graph showing the relationship between the ratio of braking force to static radial force and slip ratio according to another embodiment of this application;

[0026] Figure 7 This is a structural diagram of a tire braking performance determination device according to an embodiment of this application;

[0027] Figure 8 This is a hardware structure block diagram of a computer terminal for a method of determining tire braking performance according to an embodiment of this application. Detailed Implementation

[0028] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0029] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0030] To better understand the embodiments of this application, the technical terms involved in the embodiments of this application are explained below:

[0031] According to an embodiment of this application, a method embodiment for determining tire braking performance is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0032] Figure 1This is a flowchart of a method for determining tire braking performance according to an embodiment of this application, such as... Figure 1 As shown, the method includes the following steps:

[0033] Step S101: Obtain the target imprint length and target imprint width of the tire contact area with the ground under static load.

[0034] The target imprint length and target imprint width of the tire contact area with the ground under static load refer to the theoretical length and width of the part of the tire in contact with the ground under static (non-driving) conditions and under standard load.

[0035] Target tire contact patch length (l): This refers to the length of the tire contact patch in the vehicle's direction of travel, and can be measured when the tire is under design load and inflated to the recommended pressure. A longer contact patch length provides a larger contact area, which helps improve tire grip and stability. Target tire contact patch width (b): This refers to the width of the tire contact patch perpendicular to the vehicle's direction of travel, also measured when the tire is under design load and inflated to the recommended pressure. The contact patch width affects the tire's lateral stability, steering response, and rolling resistance.

[0036] According to some optional embodiments of this application, step S101 can be implemented by the following steps: establishing a two-dimensional simulation model of the tire based on the tire's structural material distribution diagram; performing three-dimensional processing on the two-dimensional simulation model to obtain a three-dimensional simulation model; in the three-dimensional simulation model, applying uniform gas pressure to the inner surface of the tire and applying radial force to the area where the tire contacts the ground to obtain the target imprint length and target imprint width of the tire in contact with the ground under static load.

[0037] In the above embodiment, firstly, a structural material distribution map of the tire is obtained. This map details the tire's internal structure, material distribution, and the geometric dimensions of each part. Using finite element analysis software such as ABAQUS, a two-dimensional planar model of the tire is established based on the data in the structural material distribution map. This two-dimensional planar model is as follows: Figure 2 As shown.

[0038] Then, the two-dimensional simulation model is converted to three-dimensional form using the software's 3D modeling function. Considering the tire's curved surface characteristics, a 3D tire model is generated through operations such as rotation and translation. Figure 3 As shown.

[0039] Next, the simulation is run in the software, taking into account the deformation of the tire under static load and the influence of gas pressure on the tire shape, and extracting the tire contact patch information from the simulation results, including the length and width of the patch (target patch length and target patch width).

[0040] By creating a two-dimensional simulation model of the tire and then converting it to three dimensions, the stress conditions of the tire in a static state can be simulated, allowing for precise measurement of the tire's contact patch size. This simulation model construction method fully considers the tire's structural parameters, such as tread hardness, tread pattern design, and cord arrangement, making the simulation results closer to reality. Applying gas pressure and radial force simulates the tire's load-bearing capacity under normal inflation conditions, ensuring consistency between the simulation conditions and the actual usage environment.

[0041] The above embodiments effectively overcome the limitations of experimental testing, such as the inability to control all variables and the difficulty in repeating measurements, and provide a reliable basis for tire design and performance evaluation.

[0042] Step S102: Determine the relationship between the water film thickness and the tire imprint length when braking through water, and determine the first tire imprint length when the water film thickness is zero based on the relationship.

[0043] It's understandable that the area covered when the water film thickness is zero is called the contact patch, and the area covered when the water film thickness is not zero is called the hydroplaning zone. The contact patch refers to the area where the tire directly contacts the road surface without a water film separating it; that is, the tire tread blocks or raised parts of the tread directly press against the road surface, creating friction. In the contact patch, the tire can effectively transmit the vehicle's braking force, thus achieving better braking performance. The existence of the contact patch is key to achieving good grip on wet roads. The hydroplaning zone, in contrast to the contact patch, refers to the area where a water film exists between the tire and the road surface. At high speeds or when the road surface is sufficiently deep, the tire cannot expel all the water beneath the contact surface, thus forming a water layer between part of the tire and the road surface. This phenomenon is called hydroplaning or hydroslipping. In this state, the direct contact between the tire and the road surface is reduced, friction is decreased, and the vehicle's braking performance and handling stability may be affected.

[0044] According to some alternative embodiments of this application, the correlation between the water film thickness and the imprint length of the tire during wading braking can be determined by the following steps: determining the correlation based on the target imprint length, the target imprint width, the static radial force of the tire, the dynamic viscosity of the fluid, the tire's speed, the change in imprint length and the change in water film thickness during wading braking.

[0045] Specifically, the association can be determined using the following formula:

[0046]

[0047] Where v is the dynamic viscosity of the fluid, η is the kinematic viscosity, ρ is the fluid density; F zdenoted as the static radial force of the tire; l is the target imprint length, b is the target imprint width; V is the tire's speed; x and h are the changes in imprint length and water film thickness during wading braking, respectively; n is a constant from 1 to infinity.

[0048] The static radial force F of a tire refers to the vertical pressure exerted by the tire on the ground when the tire is stationary and under a standard load. This force mainly comes from the weight of the vehicle and is transmitted to the ground through the tire. The tire's structural design, material, and inflation pressure all affect the magnitude of this radial force.

[0049] The above embodiments, by analyzing the changes in water film thickness and tire footprint length during wading braking, reveal the intrinsic relationship between tire drainage efficiency and braking performance. Increased water film thickness reduces the area of ​​direct contact between the tire and the ground, thus affecting the tire's grip and braking force. Dynamic viscosity reflects the impact of impurities in the water on the drainage process, while the tire's speed determines the drainage speed and efficiency. Determining these relationships allows for the prediction of tire braking performance under different water depths and vehicle speeds, providing important reference for tire tread design and performance optimization. This also solves the problem of difficulty in quantifying the impact of water film thickness on braking performance in actual road testing, improving the accuracy and reliability of tire performance evaluation.

[0050] Step S103: Determine the first area of ​​the tire based on the target imprint length and the target imprint width, and determine the second area of ​​the tire based on the first imprint length and the target imprint width.

[0051] Step S104: Determine the radial load of the tire's contact area during wading braking based on the first area, the second area, the critical speed of the tire when fully hydroplaning, and the tire's movement speed.

[0052] In step S104 above, the critical speed when the tire is fully hydroplaned can be determined by the following method: based on the tire's average ground pressure, water flow density, initial water film thickness, ground roughness, tread groove depth, tread porosity, and number of longitudinal tread grooves, the critical speed when the tire is fully hydroplaned is determined. Among these, the average ground pressure is the average vertical pressure of the tire in contact with the ground when braking through water, and the initial water film thickness is the thickness of the water layer on the ground before the tire contacts the ground.

[0053] Specifically, the critical speed of a tire when it is fully hydroplaned can be determined using the following formula.

[0054]

[0055] Among them, v crit p is the critical speed of the tire when it is fully hydroplaned. iThe average ground pressure of the tire, ρ is the water flow density, h0 is the initial water film thickness, and h R For surface roughness, P T ψ represents the groove depth, ψ represents the porosity of the pattern, and n represents the number of longitudinal grooves in the pattern.

[0056] Tread groove depth refers to the distance from the tire surface to the bottom of the grooves between the tire tread blocks. This depth determines the tire's ability to expel water on wet, slippery surfaces. Deeper tread grooves can hold more water, quickly draining it from the contact surface, preventing water film formation, and reducing the risk of hydroplaning. Tread porosity refers to the proportion of holes or grooves on the tire tread blocks to the total area of ​​the tread blocks. Porosity design can further increase the tire's water drainage and absorption capacity, especially at high speeds or in situations with large amounts of water. The number of longitudinal grooves refers to the number of longitudinally arranged drainage grooves on the tire tread. The main function of longitudinal grooves is to guide water in front of the tire quickly to the sides, preventing the formation of a water cushion under the tire, thus maintaining good tire-road contact.

[0057] Understandably, the critical speed at which a tire becomes fully hydroplaned refers to the speed at which a tire, while driving on a wet surface, begins to completely lose direct contact with the road surface and slides only relative to it through a film of water. This condition is called hydroplaning, also known as hydroskimming. When hydroplaning occurs, the pressure of the water film beneath the tire is sufficient to completely lift the tire, forming a water cushion between it and the road surface. The tire no longer has direct contact with the road surface but "floats" on the water film, causing a sharp decrease in tire grip and severely affecting vehicle handling and braking performance. The critical speed is the turning point from partial to full hydroplaning. When the vehicle speed exceeds this critical speed, the contact area between the tire and the road surface decreases significantly, friction decreases, and the vehicle may be at risk of losing control.

[0058] By calculating the critical speed at which a tire becomes fully hydroplaned, the point at which a tire begins to lose grip on wet surfaces can be assessed, thus determining the radial load borne by the tire in the contact patch during wading braking. Average contact pressure reflects the strength of the tire-ground contact, while water density and initial water film thickness determine the difficulty of tire drainage. Surface roughness, tread groove depth, tread porosity, and the number of longitudinal grooves are key factors affecting tire drainage capacity and grip. The above embodiment, by comprehensively considering these parameters, can accurately predict the braking performance of a tire on wet surfaces, especially the critical point at which hydroplaning begins when the water film thickness increases to a certain extent. This method not only solves the problem of accurately measuring radial load in actual wading braking tests but also provides theoretical guidance for tire tread design, ensuring the stability and safety of tires under various wet surface conditions.

[0059] Furthermore, the radial load of the tire's contact area during wading braking can be determined by the following method: based on the first area, the second area, the critical speed of the tire when fully hydroplaned, the static radial force of the tire, the tire's speed of motion, and the water flow density, the radial load of the tire's contact area during wading braking can be determined.

[0060] Specifically, the radial load of the tire's contact area during wading braking can be determined using the following formula.

[0061]

[0062] Among them, F c F represents the radial load on the tire's contact patch during wading braking. z Let A be the static radial force of the tire, and A be the first area. w For the second area, v crit Let V be the critical speed of the tire when it is fully hydroplaned, V be the speed of the tire, and ρ be the density of the water flow.

[0063] It is understandable that, since the area covered when the water film thickness is zero is the contact area, the first imprint length is the tire imprint length when the water film thickness is zero, and the second area is the product of the first imprint length and the target imprint width. Therefore, the second area is the area of ​​the contact area when the tire brakes on a wet road surface.

[0064] The above embodiment, through comparative analysis of the first and second contact areas, combined with the tire's critical speed, static radial force, motion speed, and water density, allows for precise calculation of the radial load borne by the tire's contact area during wading braking. The difference between the first and second areas reflects the change in tire contact area on dry and wet road surfaces, while the static radial force and motion speed reflect the tire's load-bearing capacity and dynamic response under different operating conditions. Water density and critical speed are key indicators for evaluating tire drainage capacity and preventing hydroplaning. By quantifying the relationship between these parameters, not only can the braking performance of the tire on wet and slippery roads be predicted, but its drainage efficiency and hydroplaning prevention ability can also be evaluated, thus providing an important basis for tire design and performance optimization.

[0065] Step S105: Determine the performance evaluation index of the tire during wading braking based on the radial load of the tire's contact area during wading braking, the length of the first imprint, and the width of the target imprint.

[0066] Specifically, the performance evaluation indicators of tires during wading braking include, but are not limited to: peak friction coefficient, optimal slip ratio, braking stiffness, and peak fade rate. The peak friction coefficient is the highest friction coefficient that a tire can achieve when braking on a wet road surface; the optimal slip ratio is the slip ratio corresponding to the peak friction coefficient during braking; braking stiffness is the degree of linear change in braking force with the slip ratio during tire braking; and the peak fade rate is the rate at which the tire braking force decreases after reaching its peak value.

[0067] According to some alternative embodiments of this application, step S105 can be implemented by the following method: using a tire braking force solution model, the radial load, first imprint length, and target imprint width of the tire contact area in the first region and the second region are calculated respectively during wading braking to obtain the braking force of the tire under different slip ratios, wherein the first region is the adhesion region where the tire does not slip, and the second region is the slip region where the tire slips; based on the braking force of the tire under different slip ratios and the static load radial force of the tire, a target curve is determined, wherein the horizontal axis of the target curve is the slip ratio, and the vertical axis is the ratio of the tire braking force to the tire static load radial force; based on the target curve, the performance evaluation index of the tire during wading braking is determined.

[0068] The above embodiment divides the tire contact area into an adhesion zone (first region) and a slip zone (second region). The slip ratio, the ratio between the tire's rotational speed during braking and the vehicle's travel speed, is a key parameter for evaluating tire wet braking performance. For both the adhesion and slip zones, the braking force of the tire under different slip ratios is calculated by integration. The calculation formula is as follows:

[0069]

[0070] Where, r h =l h / l c , l h It is the length of the adhesion zone in the tire track, l c C is the length of the first imprint mentioned above. x It is the ratio of the longitudinal stiffness of the tire tread to the area of ​​the tire tread imprint, μ. dw It is the coefficient of dynamic friction between the wet road surface and the tire.

[0071] Furthermore, a series of slip ratio values ​​were set, starting from 0 and gradually increasing until the tire completely slipped. For each set slip ratio value, the tire braking force in the first and second regions was calculated. The calculated ratios of the tire braking force to the tire's static radial force at different slip ratios were then compiled into data points. Using graphing software, the target curve was plotted with slip ratio on the horizontal axis and the ratio of tire braking force to tire's static radial force on the vertical axis, as shown below. Figure 4 As shown.

[0072] Furthermore, the highest point on the vertical axis of the target curve is found, corresponding to the maximum value of the ratio of tire braking force to static radial force, i.e., the peak friction coefficient. The horizontal axis of the point where the peak friction coefficient is located corresponds to the optimal slip ratio. The optimal slip ratio is the relative sliding ratio between the tire and the ground when the braking force is maximum. When the optimal slip ratio is within the slip ratio range of the vehicle's ABS, it is beneficial to the vehicle's braking.

[0073] Find the linear portion in the target curve. The linear portion is the segment from the initial rise to the point before the peak friction coefficient is reached. Select any two points on this linear segment and use the coordinates of these two points to calculate the slope. The calculated slope is the braking stiffness. The braking stiffness reflects the speed at which the braking force increases linearly with the slip ratio when the tire is braking on wet surfaces. It characterizes the time it takes for the tire to reach its maximum deceleration during braking.

[0074] In the target curve, find the descending segment after the peak friction coefficient. Select any two points after the peak point and calculate the rate of decrease in the ratio of braking force to radial force between these two points. The calculation method for the rate of decrease is similar to that for braking stiffness, but the focus is on the slope after the peak, which is the peak decay rate. The peak decay rate reflects the rate at which the braking force decreases from its peak when the tire brakes on a wet road surface, and is related to vehicle slip overshoot.

[0075] In summary, this application employs the following methods: obtaining the target imprint length and width of the tire's contact area with the ground under static load; determining the correlation between the tire's water film thickness and imprint length under wading braking conditions, and based on this correlation, determining the first imprint length of the tire when the water film thickness is zero; determining the first area of ​​the tire based on the target imprint length and width, and determining the second area of ​​the tire based on the first imprint length and width; determining the radial load of the tire's contact area under wading braking based on the first area, the second area, the tire's critical speed under complete hydroplaning, and the tire's speed; and determining the tire's performance evaluation indicators under wading braking based on the radial load of the tire's contact area under wading braking, the first imprint length, and the target imprint width. This approach achieves the technical effect of reducing the time and economic costs of tire design and development by using finite element analysis and mathematical models to determine the tire's braking performance during the tire design stage.

[0076] The following is a specific implementation case study. Figure 1 The steps shown are illustrated and explained by way of example.

[0077] Using the 205 / 55R16 tire as a specific example, we will calculate the braking performance of this tire on a wet road surface according to the steps described above.

[0078] Step S1: Establish a tire simulation model and obtain the tire imprint under braking conditions on a wet road surface.

[0079] Based on the material distribution diagram of the 205 / 55R16 design tire, the two-dimensional planar simulation model established in ABAQUS is as follows: Figure 2 As shown, after three-dimensional rotation, applying uniform air pressure to the inner surface of the tire and applying radial load to the road surface, the three-dimensional simulation model of the tire and the ground contact imprint results are as follows. Figure 3 As shown, the tire track length is 128mm and the track width is 158mm.

[0080] Step S2: Based on the mathematical calculation model of tire surface drainage, calculate the curve of water film thickness change along the length of the tire imprint when the tire is driving through water at a certain speed.

[0081] The tire mark is 128mm long and 158mm wide. Considering the tire pressure of a 205 / 55R16 tire at 220kPa during wading, the static radial force F of the tire is... z =4520N, water flow density ρ =1000Kg / m³ 3 Viscosity η = 1.02 × 10 -3 Pa·s, dynamic viscosity v = 1.02 × 10⁻⁶ 6 mm 2 / s, water film thickness h0=10mm. Substituting these parameters into the mathematical calculation model for tire surface drainage, we obtain the curve showing the change in water film thickness along the length of the tire indentation when braking at 40km / h. Figure 5 As shown.

[0082] Step S3: Considering the effect of the tire tread pattern when wading through water, calculate the critical speed at which the tire is fully hydroplaning based on the tread block settlement model. Given that the inflation pressure of a 205 / 55R16 HH16 tire is 220 kPa, the radial force is 4520 N, the average ground pressure is 380170 Pa, the indentation length is 128 mm, the indentation width is 158 mm, and the water flow density ρ = 1000 kg / m³ 3 The tread porosity is 0.34, the tread groove depth is 8.0 mm, there are 4 longitudinal grooves, the initial water film is 10 mm, and the road surface roughness is 1 mm. The calculated critical speed for complete hydroplaning when the tire is traveling on a 10 mm water film is 25.22 m / s = 90.79 km / h.

[0083] Step S4: Divide the tire marks left during wading and brake into sections, and calculate the radial pressure in the tire contact area.

[0084] Based on the change in water film thickness along the length of the tire imprint obtained in step S2, areas with a water film thickness of 0 are considered contact areas, while areas with a non-zero thickness are considered water-floating areas. The imprint length in the contact area is l. c=37.6mm, length of water-floating area imprint l w =90.4mm, the calculated radial load of the tire in contact area when braking on a wet road surface is 3466.9N.

[0085] Step S5: Based on the parameters obtained in the above steps, combined with the longitudinal stiffness of the tread block (0.097 MPa / mm), the tire dynamic friction coefficient (0.4), and the tire static friction coefficient (0.7), the tire braking curve (us curve) on a wet road surface is calculated as follows: Figure 6 As shown.

[0086] Based on the calculated tire braking us curve on wet roads, the evaluation index of tire braking performance on wet roads is shown in the table below.

[0087] Braking stiffness 1.4856 Optimal slip ratio 0.37 Peak friction coefficient 0.355819 Peak attenuation rate 0.182

[0088] Figure 7 This is a structural diagram of a tire braking performance determination device according to an embodiment of this application, as shown below. Figure 7 As shown, the device includes:

[0089] The acquisition module 71 is used to acquire the length and width of the target imprint in the contact area between the tire and the ground when the tire is under static load.

[0090] The first determining module 72 is used to determine the relationship between the water film thickness and the imprint length of the tire under the condition of wading braking, and to determine the first imprint length of the tire when the water film thickness is zero based on the relationship.

[0091] The second determining module 73 is used to determine the first area of ​​the tire based on the target imprint length and the target imprint width, and to determine the second area of ​​the tire based on the first imprint length and the target imprint width.

[0092] The third determining module 74 is used to determine the radial load of the tire's contact area during wading braking based on the first area, the second area, the critical speed of the tire when fully hydroplaning, and the tire's movement speed.

[0093] The fourth determining module 75 is used to determine the performance evaluation index of the tire during wading braking based on the radial load of the tire's contact area during wading braking, the length of the first imprint, and the width of the target imprint.

[0094] Optionally, the acquisition module 71 is also used to perform the following steps: establish a two-dimensional simulation model of the tire based on the tire's structural material distribution diagram; perform three-dimensional processing on the two-dimensional simulation model to obtain a three-dimensional simulation model; in the three-dimensional simulation model, apply uniform gas pressure to the inner surface of the tire and apply radial force to the area where the tire contacts the ground to obtain the target imprint length and target imprint width of the tire in contact with the ground under static load.

[0095] Optionally, the first determining module 72 is also used to perform the following steps: determining the correlation based on the target imprint length, target imprint width, static radial force of the tire, dynamic viscosity of the fluid, tire speed, change in imprint length during wading braking, and change in water film thickness.

[0096] Optionally, the third determining module 74 is further configured to perform the following steps: determining the critical speed at which the tire is fully hydroplaned based on the tire's average ground pressure, water flow density, initial water film thickness, ground roughness, tread groove depth, tread porosity, and number of longitudinal tread grooves, wherein the average ground pressure is the average vertical pressure of the tire in contact with the ground during wading braking, and the initial water film thickness is the thickness of the water layer on the ground before the tire contacts the ground; and determining the radial load of the tire's contact area during wading braking based on the first area, the second area, the critical speed, and the tire's movement speed.

[0097] Optionally, the third determining module 74 is also used to perform the following steps: determining the radial load of the tire's contact area during wading braking based on the first area, the second area, the critical speed of the tire when fully hydroplaning, the static radial force of the tire, the tire's movement speed, and the water flow density.

[0098] Optionally, the fourth determining module 75 is further configured to perform the following steps: using a tire braking force solution model to calculate the radial load, first imprint length, and target imprint width of the tire contact area in the first and second regions during wading braking, respectively, to obtain the braking force of the tire under different slip ratios, wherein the first region is the adhesion zone where the tire does not slip, and the second region is the slip zone where the tire slips; determining a target curve based on the braking force of the tire under different slip ratios and the static radial force of the tire, wherein the horizontal axis of the target curve is the slip ratio, and the vertical axis is the ratio of the tire's braking force to the tire's static radial force; and determining the tire's performance evaluation index during wading braking based on the target curve.

[0099] Optionally, the fourth determining module 75 is also used to perform the following steps: determining the maximum value of the target curve in the vertical direction as the peak friction coefficient; determining the slip ratio corresponding to the peak friction coefficient as the optimal slip ratio; determining the slope of the target curve as the braking stiffness; and determining the descent speed of the target curve after reaching the maximum value as the peak attenuation rate.

[0100] It should be noted that the above Figure 7 The modules in the above can be program modules (e.g., a set of program instructions that implement a specific function) or hardware modules. For the latter, they can be represented in the following forms, but are not limited to these: each of the above modules is represented by a processor, or the functions of each of the above modules are implemented by a processor.

[0101] It should be noted that, Figure 7 Preferred embodiments of the shown examples can be found in [reference needed]. Figure 1 The relevant descriptions of the embodiments shown will not be repeated here.

[0102] Figure 8 A hardware block diagram of a computer terminal for determining tire braking performance is shown. Figure 8 As shown, the computer terminal 80 may include one or more processors 802 (shown as 802a, 802b, ..., 802n in the figure) 802 (processor 802 may include, but is not limited to, a microprocessor MCU or a programmable logic device FPGA, etc.), a memory 804 for storing data, and a transmission module 806 for communication functions. In addition, it may also include: a display, an input / output interface (I / O interface), a universal serial bus (USB) port (which may be included as one of the ports of a BUS bus), a network interface, a power supply, and / or a camera. Those skilled in the art will understand that... Figure 8 The structure shown is for illustrative purposes only and does not limit the structure of the aforementioned electronic device. For example, the computer terminal 80 may also include... Figure 8 The more or fewer components shown, or having the same Figure 8 The different configurations shown.

[0103] It should be noted that the aforementioned one or more processors 802 and / or other data processing circuits are generally referred to herein as "data processing circuits". These data processing circuits may be embodied, in whole or in part, in software, hardware, firmware, or any other combination thereof. Furthermore, the data processing circuits may be a single, independent processing module, or may be integrated, in whole or in part, into any other element within the computer terminal 80. As involved in the embodiments of this application, the data processing circuits serve as processor control (e.g., selection of a variable resistor termination path connected to an interface).

[0104] The memory 804 can be used to store software programs and modules of application software, such as the program instructions / data storage device corresponding to the tire braking performance determination method in this embodiment. The processor 802 executes various functional applications and data processing by running the software programs and modules stored in the memory 804, thereby realizing the aforementioned tire braking performance determination method. The memory 804 may include high-speed random access memory, and may also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory 804 may further include memory remotely located relative to the processor 802, and these remote memories can be connected to the computer terminal 80 via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0105] The transmission module 806 is used to receive or send data via a network. Specific examples of the network described above may include a wireless network provided by the communication provider of the computer terminal 80. In one example, the transmission module 806 includes a Network Interface Controller (NIC), which can connect to other network devices via a base station to communicate with the Internet. In another example, the transmission module 806 may be a Radio Frequency (RF) module, used for wireless communication with the Internet.

[0106] The display can be, for example, a touchscreen liquid crystal display (LCD), which allows the user to interact with the user interface of the computer terminal 80.

[0107] It should be noted here that, in some optional embodiments, the above... Figure 8 The computer terminal shown may include hardware elements (including circuitry), software elements (including computer code stored on a computer-readable medium), or a combination of both hardware and software elements. It should be noted that... Figure 8 This is only one instance of a specific particular instance, and is intended to illustrate the types of components that may exist in the aforementioned computer terminal.

[0108] It should be noted that, Figure 8 The computer terminal shown is used to execute Figure 1 The method for determining tire braking performance shown above also applies to this electronic device, and will not be repeated here.

[0109] This application also provides a non-volatile storage medium, which includes a stored program, wherein the program, when running, controls the device where the storage medium is located to execute the above-mentioned method for determining tire braking performance.

[0110] A non-volatile storage medium performs the following functions: acquiring the target imprint length and target imprint width of the tire's contact area with the ground under static load; determining the correlation between the tire's water film thickness and imprint length under wading braking conditions, and determining the first imprint length of the tire when the water film thickness is zero based on the correlation; determining the first area of ​​the tire based on the target imprint length and target imprint width, and determining the second area of ​​the tire based on the first imprint length and target imprint width; determining the radial load of the tire's contact area under wading braking based on the first area, second area, the tire's critical speed under complete hydroplaning, and the tire's speed; and determining the tire's performance evaluation index under wading braking based on the radial load of the tire's contact area under wading braking, the first imprint length, and the target imprint width.

[0111] This application also provides an electronic device, including: a memory and a processor, wherein the processor is used to run a program stored in the memory, wherein the program executes the above-described method for determining tire braking performance.

[0112] The processor is used to run a program that performs the following functions: obtains the target imprint length and target imprint width of the tire's contact area with the ground under static load; determines the correlation between the tire's water film thickness and imprint length under wading braking conditions, and determines the first imprint length of the tire when the water film thickness is zero based on the correlation; determines the first area of ​​the tire based on the target imprint length and target imprint width, and determines the second area of ​​the tire based on the first imprint length and target imprint width; determines the radial load of the tire's contact area under wading braking conditions based on the first area, second area, the tire's critical speed under complete hydroplaning, and the tire's movement speed; and determines the tire's performance evaluation index under wading braking conditions based on the radial load of the tire's contact area under wading braking conditions, the first imprint length, and the target imprint width.

[0113] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0114] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0115] In the above embodiments of this application, the information collected is information and data authorized by the user or fully authorized by all parties, and the collection, storage, use, processing, transmission, provision, disclosure and application of the relevant data all comply with relevant laws, regulations and standards, take necessary protective measures, do not violate public order and good morals, and provide corresponding operation entry points for users to choose to authorize or refuse.

[0116] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0117] 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 units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0118] Furthermore, the functional units in the various embodiments of this application 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.

[0119] 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 technical solution of this application, in essence, or the part that contributes to related technologies, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0120] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A method for determining tire braking performance, characterized in that, include: Obtain the length and width of the target imprint in the contact area between the tire and the ground under static load; Determine the relationship between the water film thickness and the tire imprint length when braking through water, and based on the relationship, determine the first tire imprint length when the water film thickness is zero; The first area of ​​the tire is determined based on the target imprint length and the target imprint width, and the second area of ​​the tire is determined based on the first imprint length and the target imprint width. The radial load of the tire's contact area during wading braking is determined based on the first area, the second area, the critical speed of the tire when fully hydroplaned, and the tire's movement speed. The performance evaluation index of the tire during wading braking is determined based on the radial load of the tire's contact area during wading braking, the length of the first imprint, and the width of the target imprint.

2. The method according to claim 1, characterized in that, Obtain the target imprint length and target imprint width of the tire in contact with the ground under static load, including: Based on the structural material distribution diagram of the tire, a two-dimensional simulation model of the tire is established; The two-dimensional simulation model is processed into a three-dimensional model to obtain a three-dimensional simulation model; In the three-dimensional simulation model, a uniform gas pressure is applied to the inner surface of the tire, and a radial force is applied to the area where the tire contacts the ground, so as to obtain the target imprint length and target imprint width of the tire in contact with the ground under static load.

3. The method according to claim 1, characterized in that, Determining the relationship between the water film thickness of the tire and the length of the tire mark during wading braking includes: The correlation is determined based on the target imprint length, the target imprint width, the static radial force of the tire, the dynamic viscosity of the fluid, the tire's speed, the change in imprint length during wading braking, and the change in water film thickness.

4. The method according to claim 1, characterized in that, Based on the first area, the second area, the critical speed of the tire during full hydroplaning, and the tire's movement speed, the radial load of the tire's contact area during wading braking is determined, including: Based on the tire's average ground pressure, water flow density, initial water film thickness, ground roughness, tread groove depth, tread porosity, and number of longitudinal tread grooves, the critical speed at which the tire is fully hydroplaned is determined. The average ground pressure is the average vertical pressure of the tire in contact with the ground when braking through water, and the initial water film thickness is the thickness of the water layer on the ground before the tire contacts the ground. The radial load of the tire's contact area during wading braking is determined based on the first area, the second area, the critical speed, and the tire's movement speed.

5. The method according to claim 1 or 4, characterized in that, Based on the first area, the second area, the critical speed of the tire during full hydroplaning, and the tire's movement speed, the radial load of the tire's contact area during wading braking is determined, including: Based on the first area, the second area, the critical speed of the tire when fully hydroplaned, the static radial force of the tire, the tire's speed of motion, and the water flow density, the radial load of the tire's contact area during wading braking is determined.

6. The method according to claim 1, characterized in that, Based on the radial load of the tire's contact patch during wading braking, the length of the first imprint, and the width of the target imprint, the performance evaluation indicators of the tire during wading braking are determined, including: Using a tire braking force solution model, the radial load, the length of the first imprint, and the width of the target imprint of the tire contact area in the first and second regions during wading braking are calculated to obtain the braking force of the tire under different slip ratios. The first region is the adhesion region where the tire does not slip, and the second region is the slip region where the tire slips. A target curve is determined based on the braking force of the tire under different slip ratios and the static load radial force of the tire, wherein the horizontal axis of the target curve is the slip ratio and the vertical axis is the ratio of the braking force of the tire to the static load radial force of the tire. Based on the target curve, determine the performance evaluation index of the tire during wading braking.

7. The method according to claim 6, characterized in that, Based on the target curve, the performance evaluation indicators of the tire during wading braking are determined, including: The maximum value of the target curve in the vertical direction is determined as the peak friction coefficient; The slip ratio corresponding to the peak friction coefficient is determined as the optimal slip ratio; The slope of the target curve is determined as the braking stiffness; The rate at which the target curve decreases after reaching its maximum value is defined as the peak decay rate.

8. A device for determining tire braking performance, characterized in that, include: The acquisition module is used to acquire the length and width of the target imprint in the contact area between the tire and the ground when the tire is under static load. The first determining module is used to determine the correlation between the water film thickness and the imprint length of the tire under the condition of wading braking, and to determine the first imprint length of the tire when the water film thickness is zero based on the correlation. The second determining module is used to determine the first area of ​​the tire based on the target imprint length and the target imprint width, and to determine the second area of ​​the tire based on the first imprint length and the target imprint width. The third determining module is used to determine the radial load of the tire's contact area during wading braking based on the first area, the second area, the critical speed of the tire when fully hydroplaning, and the tire's movement speed. The fourth determining module is used to determine the performance evaluation index of the tire during wading braking based on the radial load of the tire's contact area during wading braking, the length of the first imprint, and the width of the target imprint.

9. A non-volatile storage medium, characterized in that, The non-volatile storage medium includes a stored program, wherein, when the program is executed, it controls the device containing the non-volatile storage medium to perform the tire braking performance determination method according to any one of claims 1 to 7.

10. An electronic device, characterized in that, include: A memory and a processor, the processor being configured to run a program stored in the memory, wherein the program, when running, executes the method for determining tire braking performance as described in any one of claims 1 to 7.

11. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the method for determining tire braking performance as described in any one of claims 1 to 7.

Images