Estimation Method, Device, Electronic Device and Storage Medium for Tire Longitudinal Force

Abstract

The present invention provides a method, device, electronic device and storage medium for estimating the longitudinal force of a tire. The method for estimating the longitudinal force of the tire includes: obtaining the vertical force of the tire to be estimated and the circumferential acceleration of the inner wall when the tire to be estimated rolls; obtaining the peak difference of the second-order gradient of the circumferential deformation of the tire to be estimated according to the circumferential acceleration of the inner wall; inputting the peak difference of the second-order gradient of the circumferential deformation and the vertical force of the tire to be estimated into a preset tire longitudinal force estimation model to obtain the longitudinal force of the tire to be estimated; the preset tire longitudinal force estimation model is obtained by fitting based on multiple groups of test calibration data, with the peak difference of the second-order gradient of the circumferential deformation of the sample tire and the vertical force of the sample tire as independent variables and the longitudinal force of the sample tire as the dependent variable. The technical solution of the present invention can improve the estimation accuracy and real-time performance of the longitudinal force of the tire.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle engineering, and particularly to a method, device, electronic device and storage medium for estimating tire longitudinal force. Background Art

[0002] The accurate estimation of tire force has always been a hot research topic in the field of vehicle engineering. In recent years, with the development of sensor technology, the method of installing sensors inside the tire for tire parameter monitoring has received extensive attention. After the sensor signals are processed by specific algorithms, various parameter information related to the tire and the road surface can be obtained.

[0003] Tire longitudinal force is a key variable in dynamic control systems such as anti-lock braking systems and automatic emergency braking. Accurately estimating and monitoring the longitudinal force can enhance the safety performance of vehicle safety control. Currently, most methods for estimating tire longitudinal force require fusing the signals of multiple sensors inside the tire, relying on complex tire models, and requiring a large amount of computation to achieve real-time estimation.

[0004] There is an urgent need for a method for estimating tire longitudinal force in real time and accurately.

[0005] Application Content

[0006] The present invention provides a method, device, electronic device and non-transitory computer-readable storage medium for estimating tire longitudinal force, so as to solve the defect that it is difficult to estimate tire longitudinal force in the prior art, and to estimate tire longitudinal force more accurately.

[0007] In a first aspect, the present invention provides a method for estimating tire longitudinal force, including: obtaining the vertical force of the tire to be estimated and the circumferential acceleration of the inner wall of the tire to be estimated when it rolls, where the circumferential acceleration is measured by an acceleration sensor arranged at the midpoint position in the transverse direction of the inner wall of the tire to be estimated; obtaining the peak difference of the second-order gradient of the circumferential deformation of the tire to be estimated according to the circumferential acceleration of the inner wall; inputting the peak difference of the second-order gradient of the circumferential deformation and the vertical force of the tire to be estimated into a preset tire longitudinal force estimation model to obtain the longitudinal force of the tire to be estimated; wherein, the preset tire longitudinal force estimation model takes the peak difference of the second-order gradient of the circumferential deformation of the sample tire and the vertical force of the sample tire as independent variables, and takes the longitudinal force of the sample tire as the dependent variable, and is obtained by fitting based on multiple groups of test calibration data.

[0008] According to the present invention, a method for estimating the longitudinal force of a tire is provided. The fitting process of the tire longitudinal force estimation model includes: under the condition of different vertical forces of a sample tire, measuring the longitudinal force of the corresponding sample tire and collecting the circumferential acceleration of the inner wall of the sample tire to obtain multiple groups of test calibration data; obtaining the peak difference of the second-order gradient of the circumferential deformation of the sample tire according to the circumferential acceleration of the inner wall of the sample tire; using the peak difference of the second-order gradient of the circumferential deformation of the sample tire and the vertical force of the sample tire as independent variables, and the longitudinal force of the sample tire as the dependent variable, and performing fitting based on multiple groups of test calibration data to obtain the tire longitudinal force estimation model.

[0009] According to the present invention, a method for estimating the longitudinal force of a tire is provided. The obtaining of the peak difference of the second-order gradient of the circumferential deformation of the tire to be estimated according to the circumferential acceleration of the inner wall includes: dividing the circumferential acceleration of the inner wall of the tire to be estimated by the square of the rotational speed of the tire to be estimated to obtain the second-order gradient of the circumferential deformation; subtracting the absolute values of the second-order gradient of the circumferential deformation at the leading edge and the trailing edge of the contact patch to obtain the peak difference of the second-order gradient of the circumferential deformation.

[0010] According to the present invention, a method for estimating the longitudinal force of a tire is provided. The tire longitudinal force estimation model includes: F x = k·Δp + b (F z ); where F x is the longitudinal force of the tire, k and b are parameters to be fitted, F z is the vertical force of the tire, and Δp is the peak difference of the second-order gradient of the circumferential deformation; b is related to the vertical force of the tire, and the tire longitudinal force has a linear relationship with the peak difference of the second-order gradient of the circumferential deformation.

[0011] According to the present invention, a method for estimating the longitudinal force of a tire is provided. The performing of fitting based on multiple groups of test calibration data with the peak difference of the second-order gradient of the circumferential deformation of the sample tire and the vertical force of the sample tire as independent variables and the longitudinal force of the sample tire as the dependent variable to obtain the tire longitudinal force estimation model includes: using the peak difference of the second-order gradient of the circumferential deformation of the sample tire and the vertical force of the sample tire as independent variables, and the longitudinal force of the sample tire as the dependent variable, and performing fitting based on multiple groups of test calibration data by using the least squares method to obtain the tire longitudinal force estimation model.

[0012] According to the present invention, a method for estimating the longitudinal force of a tire is provided. Before obtaining the vertical force of the tire to be estimated and the circumferential acceleration of the inner wall of the tire to be estimated during rolling, the estimation method further includes: measuring the circumferential acceleration of the inner wall of the tire to be estimated by using a microelectromechanical system (MEMS) acceleration sensor.

[0013] According to the present invention, a method for estimating the longitudinal force of a tire is provided. Before dividing the circumferential acceleration of the inner wall of the tire to be estimated by the square of the rotational speed of the tire to be estimated, the estimation method further includes: obtaining the rotational speed of the tire to be estimated measured by a wheel speed sensor; or, obtaining the rotational speed of the tire to be estimated according to the circumferential acceleration of the inner wall of the tire to be estimated and a first duration, where the first duration is obtained by timing the time for the tire to be estimated to rotate one week.

[0014] In a second aspect, the present invention further provides an apparatus for estimating the longitudinal force of a tire, including: a first acquisition unit configured to acquire the vertical force of the tire to be estimated and the circumferential acceleration of the inner wall of the tire to be estimated during rolling, where the circumferential acceleration is measured by an acceleration sensor provided at the midpoint position in the transverse direction of the inner wall of the tire to be estimated; a second acquisition unit configured to obtain the peak difference of the second-order gradient of the circumferential deformation of the tire to be estimated according to the circumferential acceleration of the inner wall; an estimation unit configured to input the peak difference of the second-order gradient of the circumferential deformation and the vertical force of the tire to be estimated into a preset tire longitudinal force estimation model to obtain the longitudinal force of the tire to be estimated; where the preset tire longitudinal force estimation model is based on multiple sets of test calibration data with the peak difference of the second-order gradient of the circumferential deformation of the sample tire and the vertical force of the sample tire as independent variables and the longitudinal force of the sample tire as the dependent variable, and is obtained by fitting.

[0015] According to the present invention, an apparatus for estimating the longitudinal force of a tire is provided. The apparatus for estimating the longitudinal force of the tire may further include a fitting unit; the first acquisition unit is further configured to measure the longitudinal force of the corresponding sample tire and collect the circumferential acceleration of the inner wall of the sample tire under different vertical forces of the sample tire to obtain the multiple sets of test calibration data; the second acquisition unit is further configured to obtain the peak difference of the second-order gradient of the circumferential deformation of the sample tire according to the circumferential acceleration of the inner wall of the sample tire; the fitting unit is configured to, with the peak difference of the second-order gradient of the circumferential deformation of the sample tire and the vertical force of the sample tire as independent variables and the longitudinal force of the sample tire as the dependent variable, perform fitting based on the multiple sets of test calibration data to obtain the tire longitudinal force estimation model.

[0016] According to the present invention, an apparatus for estimating the longitudinal force of a tire is provided. The second acquisition unit is further configured to divide the circumferential acceleration of the inner wall of the tire to be estimated by the square of the rotational speed of the tire to be estimated to obtain the second-order gradient of the circumferential deformation; subtract the absolute values of the second-order gradient of the circumferential deformation at the grounding leading edge and the grounding trailing edge to obtain the peak difference of the second-order gradient of the circumferential deformation.

[0017] In a third aspect, the present invention further provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, the steps of the tire longitudinal force estimation method as described in any one of the above are implemented.

[0018] In a fourth aspect, the present invention further provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the tire longitudinal force estimation method as described in any one of the above are implemented.

[0019] The tire longitudinal force estimation method, device, electronic device, and non-transitory computer-readable storage medium provided by the present invention measure the circumferential acceleration of the inner wall of the tire to obtain the circumferential acceleration, and then obtain the peak difference of the second-order gradient of the circumferential deformation of the tire. The peak difference and the vertical force of the tire are input into a preset tire longitudinal force estimation model to obtain the longitudinal force of the tire, so that the longitudinal force of the tire can be estimated accurately in real time.

[0020] Furthermore, the technical solution of the present invention uses multiple sets of experimental calibration data to fit the tire longitudinal force estimation model. When estimating the tire longitudinal force, in the case of knowing the vertical force of the tire, only the circumferential acceleration signal of the inner wall of the tire during rolling needs to be collected, processed correspondingly, and input into the preset tire longitudinal force estimation model, and the real-time longitudinal force estimation can be realized; without complex and expensive equipment, it has higher reliability and estimation accuracy, and provides longitudinal force information for vehicle safety and comfort control. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0022] Figure 1 is a schematic flow chart of the tire longitudinal force estimation method provided by the present invention;

[0023] Figure 2 is a schematic structural diagram of the tire longitudinal force estimation system provided by the present invention;

[0024] Figure 3 is a schematic diagram of the circumferential acceleration signal of the inner wall of the tire during rolling provided by the present invention;

[0025] Figure 4 is a schematic diagram of the relationship between the peak difference of the second-order gradient of the circumferential deformation of the tire and the longitudinal force under different vertical forces provided by the present invention;

[0026] Figure 5 It is a schematic structural diagram of the tire longitudinal force estimation device provided by the present invention;

[0027] Figure 6 It is a schematic structural diagram of the electronic device provided by the present invention. Specific embodiments

[0028] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0029] The following will describe in detail the technical solutions provided by each embodiment of the present invention in conjunction with the drawings.

[0030] As Figure 1 shown is a flowchart of the tire longitudinal force estimation method according to an embodiment of the present invention. The method provided by the embodiment of the present invention can be executed by any electronic device with computer processing capabilities, such as a terminal device and / or a server. As Figure 1 shown, the tire longitudinal force estimation method includes:

[0031] Step 102: Obtain the vertical force of the tire to be estimated and the circumferential acceleration of the inner wall of the tire to be estimated when it rolls. The circumferential acceleration is measured by an acceleration sensor arranged at the midpoint position in the transverse direction of the inner wall of the tire to be estimated.

[0032] Specifically, the circumferential acceleration refers to the acceleration along the circumferential direction of the inner wall of the tire to be estimated. The transverse direction refers to the direction perpendicular to the plane where a circumference of the tire to be estimated is located. Arranging at the midpoint position in the transverse direction of the inner wall of the tire to be estimated means that the acceleration sensor is arranged at any point on the circumference formed by the midpoint in the transverse direction of the inner wall of the tire to be estimated. After the acceleration sensor measures the circumferential acceleration, it outputs the circumferential acceleration. The electronic device executing the tire longitudinal force estimation method obtains the circumferential acceleration in step 102.

[0033] Step 104: Obtain the peak difference of the second-order gradient of the circumferential deformation of the tire to be estimated according to the circumferential acceleration of the inner wall.

[0034] Specifically, the gradient of the circumferential deformation of the tire surface refers to the rate of change of the circumferential deformation of the tire surface, and the second-order gradient of the circumferential deformation of the tire surface refers to the rate of change of the rate of change of the circumferential deformation of the tire surface. The peak value of the second-order gradient of the circumferential deformation includes the second-order gradient of the circumferential deformation at the grounding leading edge and the grounding trailing edge positions of the tire, and the peak difference refers to the difference between the second-order gradients of the circumferential deformation at the grounding leading edge and the grounding trailing edge positions of the tire.

[0035] Step 106: Input the peak difference of the second-order gradient of the circumferential deformation and the vertical force of the tire to be estimated into a preset tire longitudinal force estimation model to obtain the longitudinal force of the tire to be estimated.

[0036] Specifically, the vertical force of the tire to be estimated refers to the pressure exerted on the tire perpendicular to the ground or slope.

[0037] Among them, the preset tire longitudinal force estimation model takes the peak difference of the second-order gradient of the circumferential deformation of the sample tire and the vertical force of the sample tire as independent variables, and the longitudinal force of the sample tire as the dependent variable, and is obtained by fitting based on multiple groups of experimental calibration data.

[0038] In the technical solution provided by the embodiment of the present invention, a tire longitudinal force estimation model is fitted by using multiple groups of experimental calibration data. When estimating the tire longitudinal force, only the circumferential acceleration signal on the inner wall of the tire during rolling needs to be collected, processed correspondingly, and input into the preset tire longitudinal force estimation model, and real-time longitudinal force estimation can be achieved; there is no need for complex and expensive equipment, and it has higher reliability and estimation accuracy, providing longitudinal force information for vehicle safety and comfort control.

[0039] Specifically, fitting means connecting a series of points on a plane with a smooth curve. In the embodiment of the present invention, the least squares curve fitting method can be used to perform fitting based on multiple groups of experimental calibration data.

[0040] The least squares method, also known as the method of least squares, is a mathematical optimization technique. It finds the best function match for the data by minimizing the sum of the squares of the errors. Using the least squares method, unknown data can be easily obtained, and the sum of the squares of the errors between the obtained data and the actual data is minimized. The least squares method can be used for curve fitting.

[0041] Specifically, given a set of measurement data, based on the least squares principle, the functional relationship f(x, A) between variables x and y is obtained, so that it best approximates or fits the known data. f(x, A) is called the fitting model, which are some undetermined parameters. The approach is to select the parameters A such that the weighted sum of the squares of the residuals between the fitting model and the actual observed values at each point is minimized. Among them, the residual refers to the difference between the actual observed value and the fitting value in mathematical statistics. The curve fitted by applying this method is called the least squares fitting curve.

[0042] The least squares method is the most commonly used method to solve the curve fitting problem. In one embodiment, the basic idea of the least squares method is as follows:

[0043]

[0044] where, is a set of linearly independent functions selected in advance, and a k is an undetermined coefficient (k = 1, 2,..., m, m < n), and the fitting criterion is to minimize the sum of the squares of the distances between y i (i = 1, 2,..., n) and f(x i ). This criterion is called the least squares criterion.

[0045] To find the fitting curve using the least squares method, it is necessary to determine the fitting model f(x). In the embodiment of the present invention, the fitting model is the tire longitudinal force estimation model, which can be: F x = k·Δp + b (F z ); where, F x is the longitudinal force of the tire, k and b are parameters to be fitted, F z is the vertical force of the tire, and Δp is the peak difference of the second-order gradient of the circumferential deformation; b is related to the vertical force of the tire, and the tire longitudinal force has a linear relationship with the peak difference of the second-order gradient of the circumferential deformation.

[0046] Here, the fitting process of the tire longitudinal force estimation model includes: First, under the condition of different vertical forces of the sample tire, measure the longitudinal force of the corresponding sample tire and collect the circumferential acceleration of the inner wall of the sample tire to obtain multiple sets of test calibration data. Then, obtain the peak difference of the second-order gradient of the circumferential deformation of the sample tire according to the circumferential acceleration of the inner wall of the sample tire. Finally, taking the peak difference of the second-order gradient of the circumferential deformation of the sample tire and the vertical force of the sample tire as independent variables, and taking the longitudinal force of the sample tire as the dependent variable, perform fitting based on multiple sets of test calibration data to obtain the tire longitudinal force estimation model.

[0047] Among them, multiple sets of test calibration data can be obtained through bench experiments on a tire flat test bench. Under the test conditions, change the slip ratio and vertical force of the tire, and use instruments to measure the circumferential acceleration and longitudinal force of the inner wall of the tire under each working condition respectively, then the required test calibration data can be obtained. Specifically, different slip ratios mean different peak differences of circumferential acceleration. By using different slip ratio conditions of the tire, a larger range of data can be obtained.

[0048] For the above tire longitudinal force estimation model, take the longitudinal force in multiple sets of test calibration data as F x, the peak difference of the circumferential deformation second-order gradient obtained from the circumferential acceleration in multiple groups of test calibration data is taken as Δp, and the parameters k and b (F z ) are obtained by least squares fitting, that is, the tire longitudinal force estimation model can be obtained by fitting. The fitted tire longitudinal force estimation model can be used for real-time tire longitudinal force estimation.

[0049] Although the least squares method is used for fitting to obtain the tire longitudinal force estimation model in the embodiments of the present invention, the fitting method is not limited thereto.

[0050] In the embodiments of the present invention, before step 102, a micro-electro-mechanical system (MEMS) acceleration sensor can be used to measure the circumferential acceleration of the inner wall of the tire to be estimated.

[0051] The MEMS (Micro-Electro-Mechanical System) acceleration sensor has the advantages of small volume, low energy consumption, and can withstand the harsh working environment inside the tire, and can collect acceleration signals without changing the tire characteristics.

[0052] Figure 2 is a schematic structural diagram of the tire longitudinal force estimation system provided by the present invention. As Figure 2 shown, a tire longitudinal force estimation system can be established based on the acceleration sensor 202. The system includes an upper computer and a lower computer.

[0053] Among them, the lower computer includes an acceleration sensor 202 and a lower computer processor 204, and the upper computer includes an upper computer processor 206 and a memory 208.

[0054] Specifically, the acceleration sensor 202 and the lower computer processor 204 can be arranged at the midpoint position in the transverse direction of the inner wall of the tire. The acceleration sensor 202 and the lower computer processor 204 can be arranged on the same printed circuit board.

[0055] In addition, wireless communication modules (not shown in the figure) can be respectively provided in the upper computer and the lower computer for wireless communication between the upper computer and the lower computer. In some embodiments, the wireless communication module can be integrated in the upper computer processor and the lower computer processor.

[0056] In one embodiment, the lower computer can be wrapped with a rubber sleeve. Then, the rubber sleeve wrapped with the lower computer is fixed at the midpoint position in the transverse direction of the inner wall of the tire using an adhesive.

[0057] The acceleration sensor 202 in the lower computer acquires the circumferential acceleration signal of the inner wall of the tire during tire rolling and sends it to the lower computer processor 204, and the lower computer processor 204 sends the circumferential acceleration signal to the upper computer through the built-in wireless communication module or an external wireless communication module.

[0058] In the upper computer, the upper computer processor 206 is configured to receive the circumferential acceleration signal sent by the lower computer through the built-in wireless communication module or an external wireless communication module, and estimate the longitudinal force received by the tire according to the circumferential acceleration signal and a preset longitudinal force estimation model. The memory 208 is used to store algorithm programs, various models such as the longitudinal force estimation model, and signal data.

[0059] The tire longitudinal force estimation system provided by the embodiment of the present invention only needs to collect the circumferential acceleration signal of the inner wall of the tire during tire rolling, and can achieve real-time longitudinal force estimation; it does not require complex and expensive equipment, has higher reliability and estimation accuracy, and provides longitudinal force information for vehicle safety and comfort control.

[0060] Figure 3 is a schematic diagram of the circumferential acceleration signal of the inner wall of the tire during rolling provided by the embodiment of the present invention. As Figure 3 shown, when the acceleration sensor is about to enter the grounding area, due to the circumferential extrusion of the tire surface, a negative acceleration peak will be generated; at the center position of the grounding area, there is no relative movement between the acceleration sensor and the ground, and the circumferential acceleration is zero; when the acceleration sensor is about to leave the grounding area, due to the circumferential stretching of the tire surface, a positive acceleration peak will be generated. The acceleration peak positions correspond to the leading and trailing edge positions of the grounding.

[0061] The acceleration sensor arranged on the inner wall of the tire rolls with the tire. During the transition between grounding and non-grounding at its location, the circumferential acceleration signal will change sharply, and this sharp change corresponds to the turning positions of the leading and trailing edges of the tire grounding.

[0062] In step 104, dividing the circumferential acceleration of the inner wall of the tire to be estimated by the square of the rotational speed of the tire to be estimated can obtain the second-order gradient of circumferential deformation; subtracting the absolute values of the second-order gradient of circumferential deformation at the leading edge and trailing edge of grounding, the peak difference of the second-order gradient of circumferential deformation can be obtained.

[0063] In step 104, before dividing the circumferential acceleration of the inner wall by the square of the rotational speed of the tire to be estimated, it is also necessary to obtain the rotational speed of the tire to be estimated, and the specific obtaining method may include but is not limited to the following two.

[0064] The first one is: obtaining the rotational speed of the tire to be estimated measured by the wheel speed sensor.

[0065] The second method is: obtaining the rotational speed of the tire to be estimated based on the circumferential acceleration of the inner wall of the tire to be estimated and the first duration, where the first duration is obtained by timing the time for the tire to be estimated to rotate one week.

[0066] The embodiment of the present invention explains the acceleration generation mechanism according to the tire rolling kinematic model, and this mechanism provides an effective theoretical guidance for tire longitudinal force estimation. Using the method of hybrid Euler-Lagrange to describe the tire rolling deformation, the circumferential acceleration on the tire surface can be expressed as:

[0067] a u =Ω 2 -u″;

[0068] where, a u is the circumferential acceleration, Ω is the wheel rotational speed, u″ is the second-order gradient of the circumferential deformation on the tire surface, and this mechanism links the tire surface deformation and acceleration, providing a theoretical support for developing tire parameter estimation applications based on acceleration sensors.

[0069] When there is a tire longitudinal force, in the circumferential direction of the tire surface in the contact area, the deformation form of the tire surface will change. Specifically, the tire surface in the contact area will shift towards the longitudinal force direction relative to the wheel center position, resulting in changes in the second-order gradient of the tire surface deformation at the leading and trailing edges of the contact area. Therefore, the tire longitudinal force can be estimated by the changes in the second-order gradient of the tire surface deformation at the leading and trailing edges of the contact area.

[0070] The embodiment of the present invention proposes a mechanism for the influence of tire longitudinal force on tire surface deformation. This mechanism is combined with the above-mentioned tire circumferential acceleration generation mechanism to reveal the relationship between the peak difference of the second-order gradient of circumferential deformation and the longitudinal force.

[0071] The tire flexible ring model can describe the tire surface deformation caused by the force distribution in the tire contact area. By solving the tire flexible ring model under the working conditions of applying different longitudinal forces, the circumferential deformation under different tire longitudinal forces can be obtained. Combining with the circumferential acceleration expression, the circumferential acceleration under different tire longitudinal forces can be obtained. At the same time, the vertical force of different tires will also affect the tire surface deformation.

[0072] Figure 4 is the relationship between the peak difference of the second-order gradient of circumferential deformation and the longitudinal force under different vertical forces provided by the embodiment of the present invention. As Figure 4 shown, under the same vertical force, the peak difference of the second-order gradient of circumferential deformation and the longitudinal force show a linear relationship; the slopes of the relationship lines under different vertical forces are the same, but there is a distance. Therefore, the relationship between the peak difference of the second-order gradient of circumferential deformation and the longitudinal force can be expressed as: F x =k·Δp + b(F z ); where, F xis the longitudinal force of the tire, k and b are parameters to be fitted, F z is the vertical force of the tire, and Δp is the peak difference of the second-order gradient of the circumferential deformation; b is related to the vertical force of the tire, and the longitudinal force of the tire has a linear relationship with the peak difference of the second-order gradient of the circumferential deformation.

[0073] The above expression is the estimation model of the tire longitudinal force, which describes how to estimate the longitudinal force according to the circumferential acceleration signal in a simple linear form.

[0074] In actual use, the vertical force can be measured by a weighbridge or estimated by using an acceleration sensor in combination with relevant algorithms.

[0075] In the tire longitudinal force estimation method according to the embodiment of the present invention, the circumferential acceleration is measured based on the circumferential acceleration of the inner wall of the tire, and then the peak difference of the second-order gradient of the circumferential deformation of the tire is obtained. The peak difference and the vertical force of the tire are input into a preset tire longitudinal force estimation model to obtain the longitudinal force of the tire, so that the longitudinal force of the tire can be estimated accurately in real time.

[0076] Next, the tire longitudinal force estimation device provided by the present invention will be described. The tire longitudinal force estimation device described below can be mutually corresponding and referred to the tire longitudinal force estimation method described above.

[0077] Figure 5 is a schematic structural diagram of the tire longitudinal force estimation device provided by the present invention. As Figure 5 shown, the tire longitudinal force estimation device provided by the embodiment of the present invention includes:

[0078] The first acquisition unit 502 is configured to acquire the vertical force of the tire to be estimated and the circumferential acceleration of the inner wall of the tire to be estimated during rolling. The circumferential acceleration is measured by an acceleration sensor arranged at the midpoint position in the transverse direction of the inner wall of the tire to be estimated.

[0079] The second acquisition unit 504 is configured to obtain the peak difference of the second-order gradient of the circumferential deformation of the tire to be estimated according to the circumferential acceleration of the inner wall of the tire to be estimated.

[0080] The estimation unit 506 is configured to input the peak difference of the second-order gradient of the circumferential deformation and the vertical force of the tire to be estimated into a preset tire longitudinal force estimation model to obtain the longitudinal force of the tire to be estimated; wherein, the preset tire longitudinal force estimation model is based on the peak difference of the second-order gradient of the circumferential deformation of the sample tire and the vertical force of the sample tire as independent variables, and the longitudinal force of the sample tire as the dependent variable, and is obtained by fitting based on multiple groups of test calibration data.

[0081] In the technical solution provided by the embodiment of the present invention, a tire longitudinal force estimation model is fitted by using multiple groups of experimental calibration data. When estimating the tire longitudinal force, only the circumferential acceleration signal of the inner wall of the tire during rolling needs to be collected, processed correspondingly and input into the preset tire longitudinal force estimation model, and the real-time longitudinal force estimation can be realized; there is no need for complex and expensive equipment, and it has higher reliability and estimation accuracy, providing longitudinal force information for vehicle safety and comfort control.

[0082] The tire longitudinal force estimation model can be: F x = k·Δp + b(F z ); where F x is the longitudinal force of the tire, k and b are parameters to be fitted, F z is the vertical force of the tire, and Δp is the peak difference of the second-order gradient of the circumferential deformation; b is related to the vertical force of the tire, and the tire longitudinal force has a linear relationship with the peak difference of the second-order gradient of the circumferential deformation.

[0083] For the above tire longitudinal force estimation model, the longitudinal force in multiple groups of test calibration data is used as F x , and the peak difference of the second-order gradient of the circumferential deformation obtained from the circumferential acceleration in multiple groups of test calibration data is used as Δp. The parameters k and b(F z ) are obtained by least squares fitting, and thus the tire longitudinal force estimation model can be fitted. The fitted tire longitudinal force estimation model can be used for real-time tire longitudinal force estimation.

[0084] The tire longitudinal force estimation device provided by the embodiment of the present invention may further include a fitting unit.

[0085] Specifically, the first acquisition unit 502 is further configured to measure the longitudinal force of the corresponding sample tire and collect the circumferential acceleration of the inner wall of the sample tire under the conditions of different vertical forces of the sample tire, so as to obtain multiple groups of test calibration data.

[0086] The second acquisition unit 504 is further configured to obtain the peak difference of the second-order gradient of the circumferential deformation of the sample tire according to the circumferential acceleration of the inner wall of the sample tire.

[0087] The above-mentioned fitting unit is configured to use the peak difference of the second-order gradient of the circumferential deformation of the sample tire and the vertical force of the sample tire as independent variables, and the longitudinal force of the sample tire as the dependent variable, and perform fitting based on multiple groups of test calibration data to obtain the tire longitudinal force estimation model.

[0088] The second acquisition unit 504 is further configured to divide the circumferential acceleration of the inner wall of the tire to be estimated by the square of the rotation speed of the tire to be estimated to obtain the second-order gradient of the circumferential deformation; subtract the absolute values of the second-order gradient of the circumferential deformation at the grounding leading edge and the grounding trailing edge to obtain the peak difference of the second-order gradient of the circumferential deformation.

[0089] The above fitting unit is also used to take the peak difference of the second-order gradient of the circumferential deformation of the sample tire and the vertical force of the sample tire as independent variables, and the longitudinal force of the sample tire as the dependent variable. Based on multiple sets of test calibration data, the least squares method is used for fitting to obtain a tire longitudinal force estimation model.

[0090] It can be understood that the above tire longitudinal force estimation device can implement each step of the tire longitudinal force estimation method provided in the foregoing embodiments. The relevant explanations regarding the tire longitudinal force estimation method are applicable to the tire longitudinal force estimation device and will not be elaborated here.

[0091] The tire longitudinal force estimation device according to the embodiment of the present invention measures the circumferential acceleration of the inner wall of the tire to obtain the circumferential acceleration, and then obtains the peak difference of the second-order gradient of the circumferential deformation of the tire. The peak difference and the vertical force of the tire are input into a preset tire longitudinal force estimation model to obtain the longitudinal force of the tire, so that the longitudinal force of the tire can be estimated accurately in real time.

[0092] Figure 6 An example of a schematic physical structure diagram of an electronic device is shown as Figure 6 As shown, the electronic device may include: a processor 610, a communication interface 620, a memory 630, and a communication bus 640. Among them, the processor 610, the communication interface 620, and the memory 630 communicate with each other through the communication bus 640. The processor 610 can call the logical instructions in the memory 630 to execute the tire longitudinal force estimation method, which includes: obtaining the vertical force of the tire to be estimated and the circumferential acceleration of the inner wall of the tire to be estimated when it rolls, and the circumferential acceleration is measured by an acceleration sensor arranged at the midpoint position in the transverse direction of the inner wall of the tire to be estimated; obtaining the peak difference of the second-order gradient of the circumferential deformation of the tire to be estimated according to the circumferential acceleration of the inner wall; inputting the peak difference of the second-order gradient of the circumferential deformation and the vertical force of the tire to be estimated into a preset tire longitudinal force estimation model to obtain the longitudinal force of the tire to be estimated; wherein, the preset tire longitudinal force estimation model takes the peak difference of the second-order gradient of the circumferential deformation of the sample tire and the vertical force of the sample tire as independent variables, and the longitudinal force of the sample tire as the dependent variable, and is obtained by fitting based on multiple sets of test calibration data.

[0093] In addition, when the logical instructions in the above-mentioned memory 630 are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs that can store program codes.

[0094] On the other hand, the present invention also provides a computer program product. The computer program product includes a computer program stored on a non-transitory computer-readable storage medium. The computer program includes program instructions. When the program instructions are executed by a computer, the computer can execute the tire longitudinal force estimation method provided by the above-mentioned various methods. The method includes: obtaining the vertical force of the tire to be estimated and the circumferential acceleration of the inner wall of the tire to be estimated when it rolls. The circumferential acceleration is measured by an acceleration sensor arranged at the midpoint position in the transverse direction of the inner wall of the tire to be estimated; obtaining the peak difference of the second-order gradient of the circumferential deformation of the tire to be estimated according to the circumferential acceleration of the inner wall; inputting the peak difference of the second-order gradient of the circumferential deformation and the vertical force of the tire to be estimated into a preset tire longitudinal force estimation model to obtain the longitudinal force of the tire to be estimated; wherein the preset tire longitudinal force estimation model uses the peak difference of the second-order gradient of the circumferential deformation of the sample tire and the vertical force of the sample tire as independent variables, and the longitudinal force of the sample tire as the dependent variable, and is obtained by fitting based on multiple groups of test calibration data.

[0095] In another aspect, the present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it is configured to execute the method for estimating the longitudinal force of a tire provided above. The method includes: obtaining the vertical force of the tire to be estimated and the circumferential acceleration of the inner wall of the tire to be estimated during rolling, where the circumferential acceleration is measured by an acceleration sensor disposed at the midpoint position in the transverse direction of the inner wall of the tire to be estimated; obtaining the peak difference of the second-order gradient of the circumferential deformation of the tire to be estimated based on the circumferential acceleration of the inner wall; inputting the peak difference of the second-order gradient of the circumferential deformation and the vertical force of the tire to be estimated into a preset tire longitudinal force estimation model to obtain the longitudinal force of the tire to be estimated; where the preset tire longitudinal force estimation model is obtained by fitting based on multiple sets of experimental calibration data with the peak difference of the second-order gradient of the circumferential deformation of the sample tire and the vertical force of the sample tire as independent variables and the longitudinal force of the sample tire as the dependent variable.

[0096] The device embodiments described above are merely illustrative. 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 to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative efforts.

[0097] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the essence of the above technical solution, or the part that contributes to the prior art, can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0098] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for estimating the longitudinal force of a tire, characterized in that, Comprising: Obtaining the vertical force of the tire to be estimated and the circumferential acceleration of the inner wall of the tire to be estimated during rolling, where the circumferential acceleration is measured by an acceleration sensor disposed at the midpoint position in the transverse direction of the inner wall of the tire to be estimated; Obtaining the peak difference of the second-order gradient of the circumferential deformation of the tire to be estimated based on the circumferential acceleration of the inner wall; Inputting the peak difference of the second-order gradient of the circumferential deformation and the vertical force of the tire to be estimated into a preset tire longitudinal force estimation model to obtain the longitudinal force of the tire to be estimated; Wherein, the preset tire longitudinal force estimation model is obtained by fitting, with the peak difference of the second-order gradient of the circumferential deformation of the sample tire and the vertical force of the sample tire as independent variables, and the longitudinal force of the sample tire as the dependent variable, based on multiple groups of test calibration data; Wherein, the tire longitudinal force estimation model includes: F x = k·Δp + b (F z ); Among them, F x is the longitudinal force of the tire, k and b are parameters to be fitted, and F z is the vertical force of the tire, and Δp is the peak difference of the second-order gradient of the circumferential deformation; the b is related to the vertical force of the tire, and the longitudinal force of the tire has a linear relationship with the peak difference of the second-order gradient of the circumferential deformation.

2. The method for estimating the longitudinal force of a tire according to claim 1, wherein The fitting process of the tire longitudinal force estimation model includes: Under the condition of different vertical forces of the sample tires, measuring the corresponding longitudinal forces of the sample tires and collecting the circumferential accelerations of the inner walls of the sample tires to obtain the multiple groups of test calibration data; Obtaining the peak difference of the second-order gradient of the circumferential deformation of the sample tire based on the circumferential acceleration of the inner wall of the sample tire; Using the peak difference of the second-order gradient of the circumferential deformation of the sample tire and the vertical force of the sample tire as independent variables, and the longitudinal force of the sample tire as the dependent variable, and fitting based on multiple groups of test calibration data to obtain the tire longitudinal force estimation model.

3. The method for estimating the longitudinal force of a tire according to claim 1 or 2, characterized in that, The obtaining the peak difference of the second-order gradient of the circumferential deformation of the tire to be estimated based on the circumferential acceleration of the inner wall includes: Dividing the circumferential acceleration of the inner wall of the tire to be estimated by the square of the rotational speed of the tire to be estimated to obtain the second-order gradient of the circumferential deformation; Subtracting the absolute values of the second-order gradient of the circumferential deformation at the leading edge and trailing edge of the contact patch to obtain the peak difference of the second-order gradient of the circumferential deformation.

4. The method for estimating the longitudinal force of a tire according to claim 1, characterized in that, The using the peak difference of the second-order gradient of the circumferential deformation of the sample tire and the vertical force of the sample tire as independent variables, and the longitudinal force of the sample tire as the dependent variable, and fitting based on multiple groups of test calibration data to obtain the tire longitudinal force estimation model includes: using the peak difference of the second-order gradient of the circumferential deformation of the sample tire and the vertical force of the sample tire as independent variables, and the longitudinal force of the sample tire as the dependent variable, and performing fitting based on multiple groups of test calibration data by using the least squares method to obtain the tire longitudinal force estimation model.

5. The method for estimating the longitudinal force of a tire according to claim 1, characterized in that, Before obtaining the vertical force of the tire to be estimated and the circumferential acceleration of the inner wall of the tire to be estimated during rolling, the estimation method further includes: Measuring the circumferential acceleration of the inner wall of the tire to be estimated by using a microelectromechanical system (MEMS) acceleration sensor.

6. The method for estimating the longitudinal force of a tire according to claim 3, characterized in that, Before dividing the circumferential acceleration of the inner wall of the tire to be estimated by the square of the rotational speed of the tire to be estimated, the estimation method further includes: Obtaining the rotational speed of the tire to be estimated measured by a wheel speed sensor; or Obtaining the rotational speed of the tire to be estimated based on the circumferential acceleration of the inner wall of the tire to be estimated and a first time period, where the first time period is obtained by timing the time for the tire to be estimated to rotate one week.

7. An estimation device for tire longitudinal force, characterized in that, Comprising: A first acquisition unit, configured to acquire a vertical force of a tire to be estimated and a circumferential acceleration of an inner wall of the tire to be estimated during rolling, where the circumferential acceleration is measured by an acceleration sensor disposed at a midpoint position in a transverse direction of the inner wall of the tire to be estimated; A second acquisition unit, configured to obtain a peak difference of a second-order gradient of circumferential deformation of the tire to be estimated according to the circumferential acceleration of the inner wall; An estimation unit, configured to input the peak difference of the second-order gradient of circumferential deformation and the vertical force of the tire to be estimated into a preset tire longitudinal force estimation model to obtain a longitudinal force of the tire to be estimated; Wherein, the preset tire longitudinal force estimation model is obtained by fitting based on a plurality of groups of test calibration data with a peak difference of a second-order gradient of circumferential deformation of a sample tire and the vertical force of the sample tire as independent variables and the longitudinal force of the sample tire as a dependent variable; Wherein, the tire longitudinal force estimation model includes: F x = k·Δp + b (F z ); Among them, F x is the longitudinal force of the tire, k and b are parameters to be fitted, and F z is the vertical force of the tire, and Δp is the peak difference of the second-order gradient of the circumferential deformation; the b is related to the vertical force of the tire, and the tire longitudinal force has a linear relationship with the peak difference of the second-order gradient of the circumferential deformation.

8. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the program, the steps of the method for estimating the tire longitudinal force according to any one of claims 1 to 6 are implemented.

9. A non-transitory computer-readable storage medium storing a computer program thereon, characterized in that, When the computer program is executed by the processor, the steps of the method for estimating the tire longitudinal force according to any one of claims 1 to 6 are implemented.

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