A method for estimating the tread depth of tires mounted on a vehicle.

Abstract

The present invention relates to an estimation method (100) for estimating the tread depth of a given tire from a set mounted on a given vehicle under driving conditions, the method being implemented in at least one processor of a system performing the estimation method (100), the at least one processor comprising an analysis application module for applying data items representing the operating characteristics of a given tire. The present invention also relates to a system comprising a communication network for managing data items representing the operating characteristics of a given tire from a set mounted on a given vehicle under driving conditions, the communication network comprising at least one communication server for executing program instructions stored in the memory of one or more processors of the system in order to implement the disclosed method.

Description

[Technical Field]

[0001] This invention relates to a method for comprehensively estimating wear, a method for predicting the end of tire life under vehicle usage conditions, and a system for implementing these methods. More specifically, this invention uses a temperature model to obtain an accurate estimate of tread pattern height in order to predict the remaining service life of a tire. [Background technology]

[0002] In the field of methods for evaluating tire wear under vehicle usage conditions, a simple method for determining wear is often considered to be an evaluation of overall wear corresponding to the average decrease in tread height (or "tread pattern height"). For this purpose, intermediate physical quantities sensitive to tire tread wear, such as tire rolling radius or pseudo-slip stiffness K, are used. X It is generally assumed that this will be used. This second quantity represents the slope of the curve that expresses the longitudinal force resulting from the change in rotational speed between the wheel center and the tread as the tire travels on the road surface. The sensitivity of pseudo-slip stiffness to overall wear of the tire casing is far higher than the sensitivity of rolling radius.

[0003] Methods for characterizing the overall wear of a tire tread in use using such a second quantity are known from the prior art. Specifically, this quantity is sensitive to the decrease in tread pattern height, which characterizes the overall wear of the tire casing.

[0004] However, this physical quantity is also sensitive to other parameters such as inflation pressure (or "pressure"), temperature, the load supported by the mounting assembly (or "load"), and the characteristics of the road surface on which the mounting assembly travels (in this case, the "influence parameter"). As disclosed in the applicant's International Publication No. WO 2020 / 120923, by considering changes in all influence parameters, it is possible to extract the change in longitudinal stiffness solely due to the decrease in the tread pattern height of the tire. For this purpose, the recommended solution is to consider changes in these influence parameters through additional measurements or additional information.

[0005] By considering all parameters that have an impact (including but not limited to load, pressure, temperature, and tread pattern height), the estimation of the overall wear of the tire and the prediction of the end of life become more accurate. However, there are also methods that involve slip calculations for wear estimation (see, for example, U.S. Patent No. 10,603,962), but none of them seem to use a similar relational expression that enables progression from the pseudo-slip stiffness K X to the tread pattern height. In principle, an increase in pseudo-slip stiffness corresponds to a decrease in tread pattern height. In fact, simulations show that the pseudo-slip stiffness increases significantly with wear, regardless of the roughness of the road surface. However, the internal air temperature of the tire is known to indicate the average thermal state of the tire.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] Based on a physical model, it is theoretically possible to estimate the remaining tread pattern height of a tire assembly mounted on a vehicle, and subsequently infer the remaining service life of the tire from that. Consequently, this invention focuses on estimating temperature to obtain the most accurate possible estimate of tread pattern height in order to determine the remaining service life of a tire. [Means for solving the problem]

[0008] The present invention relates to an estimation method for estimating the tread pattern height of a particular tire of an assembly mounted on a particular vehicle under specific driving conditions, wherein the tire has a crown extended by two sidewalls terminating at two beads, exhibiting rotational symmetry about a natural axis of rotation, the crown having a tread located radially outward of the tire with respect to the natural axis of rotation, the tread having an average tread pattern height h, the estimation method is implemented in at least one processor of a system performing this method, the at least one processor having an analysis application module to which data representing the operating characteristics of the particular tire is applied, and the estimation method is - An identification step to identify the tires of an assembly attached to a vehicle; - A selection step of selecting a passage function β defined by the road section and the tire tread stiffness; - The transfer function F of the mounting assembly is determined by the pseudo-slip stiffness K on the reference road surface. X And a selection step to choose between the influencing parameters; In a predetermined measurement cycle, - At least one force F acting on the mounting assembly when the vehicle is traveling in a straight line with changes in acceleration on a dry road section. X A determination step of determining at least one slip ratio G% at the wheel center of the mounting assembly; - An acquisition step to obtain the usage parameters of the mounting assembly, - A step of determining the load (Z) that the mounting assembly will experience under driving conditions; - A step of determining the temperature (T) of the mounting assembly under running conditions; - A step of determining the expansion pressure (P) of the internal cavity of the mounting assembly under running conditions; An acquisition step including, Including, Where the temperature is of the following type Determined according to the mathematical model of JPEG2026519859000002.jpg11170, where T amb i Is the initial temperature in Kelvin units, Pf Tamb f And Pi Tamb i Are the pressures at the end and start of a predetermined mileage for a specific tire, respectively.

[0009] In some embodiments of the method of the present invention, the tread thickness E of a specific tire is of the following type Determined according to the mathematical model of JPEG2026519859000003.jpg12170, The transfer function F of this mathematical model includes at least the expansion pressure P, temperature T, load Z, and tread thickness E as influencing factors, The first pseudo-slip stiffness K of this mathematical model X actual And the second pseudo-slip stiffness K X ref Is related to the determination of the thickness E.

[0010] In some embodiments of the method of the present invention, the method further includes an investigation step for examining the state of aging of a specific tire, during which the identification information of the mounting assembly is used to know the usage history of the specific tire.

[0011] In some embodiments of the method of the present invention, the method further includes, - The force F measured during running on a dry road section XA plotting step of plotting a point cloud, which is performed based on the slip ratio G%, and during this step, a first pseudo-slip stiffness K for the actual road surface corresponding to the dry road section. actual An estimate of the step is obtained; - A second pseudo-slip stiffness K is obtained by applying the usage parameters measured during the step and the tread pattern height h obtained during the step to the transfer function F obtained during the selection step. ref Estimation steps to estimate; Includes.

[0012] In some embodiments of the method of the present invention, the passage function β is selected from a list of possible passage functions β that may represent the central characteristics of the road section that a particular vehicle will encounter.

[0013] In some embodiments of the method of the present invention, the method further includes an evaluation step of evaluating the average tread pattern height by comparing the evaluated average height with the specific height of a particular tire.

[0014] In some embodiments of the method of the present invention, the method further includes an acquisition step of acquiring a change ΔU of a parameter U related to the use of a particular tire between two acquisitions of the average tread pattern height.

[0015] In some embodiments of the method of the present invention, the method further includes an evaluation step of evaluating the wear rate of a particular tire, which includes evaluating the tread at the time the average tread pattern height of the particular tire is obtained.

[0016] In some embodiments of the method of the present invention, the method further includes an evaluation step of evaluating the remaining service life of a particular tire, the evaluation step of evaluating the end-of-life prediction according to a parameter U related to the use of the particular tire; The end-of-life prediction is obtained by combining the results of an identification step, an evaluation step that assesses the average tread pattern height, and an evaluation step that assesses the wear rate of a particular tire.

[0017] The present invention also relates to a system comprising a communication network that manages data representing the operating characteristics of a particular tire based on an assembly installed on a particular vehicle under driving conditions, wherein the communication network comprises at least one communication server that executes program instructions stored in the memory of one or more processors of the system in order to implement the disclosed method.

[0018] Further aspects of the present invention will become apparent from the following detailed description.

[0019] The essence and various advantages of this invention will become clearer upon reading the following detailed description in conjunction with the accompanying drawings, which show the same reference numerals for the same elements throughout. [Brief explanation of the drawing]

[0020] [Figure 1] This shows the components of a tire in the meridional plane. [Figure 2] This document illustrates one embodiment of the estimation method for estimating the tread pattern height of a tire according to the present invention. [Figure 3] This shows a temperature simulation curve for a tire assembly mounted on a vehicle. [Figure 4] This shows a simulation curve of the average temperature rise for a tire assembly attached to a vehicle. [Modes for carrying out the invention]

[0021] When considering the characteristics of a tire for estimating tread pattern height, its geometry must be taken into account. A tire is an object with a known geometry and generally comprises multiple layers of rubber (or "layers") stacked together, along with a structure made of metal or fabric fibers that forms a carcass reinforcing the tire structure. The properties of the rubber and the reinforcing material are selected according to the desired final characteristics. Figure 1 schematically shows a tire 10 with two circumferential beads intended to fasten the tire to a rim in a conventional manner. Each bead is provided with an annular reinforcing bead wire. The structure of a tire is usually described by depicting its components in the meridional plane, i.e., the plane containing the tire's axis of rotation. Radial, axial, and circumferential directions represent the direction perpendicular to the tire's axis of rotation, the direction parallel to the tire's axis of rotation, and the direction perpendicular to either meridional plane, respectively. The expressions "radially," "axially," and "circumferentially" refer to the "radial," "axial," and "circumferential" directions of the tire, respectively. The expressions "radially inward of ~" and "radially outward of ~" mean "closer to the tire's axis of rotation than ~" and "further from the tire's axis of rotation than ~," respectively.

[0022] The tire 10 also comprises a tread 12 added to the outer surface of the tire. The tread 12 is intended to contact the road surface via a tread surface 12a. The tire 10 further comprises a crown reinforcement including a working reinforcement 14 and a hoop reinforcement 16, the working reinforcement 14 having working layers represented by layers 14a and 14b. The tire 10 also comprises two sidewalls (one sidewall 18 is shown in Figure 1) and two beads 20 reinforced with bead wires 22. A radial carcass layer 24 extends from one bead to the other and surrounds the bead wires in a known manner. The tread 12 comprises a reinforcement composed of overlapping layers including, for example, known reinforcing threads. In some embodiments, the tire may include a liner 26 for discharging static electricity generated during driving.

[0023] The tread 12 is divided into two circumferential surfaces in the radial direction, the outermost radial surface being the tread surface 12a and the innermost radial surface being called the tread pattern end wall. The tread pattern end wall (or "end wall") is defined as a surface that is shifted radially inward from the tread surface by a radial distance equal to the tread pattern depth. This depth usually decreases along the outermost axial part of the tread 12 (called the shoulder).

[0024] Furthermore, the tire tread is divided axially by two sides. The tread is also composed of one or more rubber compounds. The expression "rubber compound" means a rubber composition comprising at least one elastomer and one filler.

[0025] Referring to a figure where the same reference number identifies the same element, Figure 2 shows a flowchart of one embodiment of the estimation method (or “Estimation Method”) 100 for estimating the tread pattern height of a tire mounted on a vehicle according to the present invention. The estimation method of the present invention is based on the wear condition of a particular tire relating to a particular vehicle, the wear condition being defined by the remaining tread pattern height.

[0026] It should be noted that the wear condition is expressed as a value of 1 or more, representing the difference between a new condition (represented by a tire that has never been mounted on a vehicle) and a worn condition (represented by a tire that has been taken out of service because it has reached the wear threshold). The wear condition can take the form of a single value such as the minimum tread pattern height, a set of values ​​that define the tread pattern height in the meridional plane of the tire (e.g., a 2D profile), or a set of values ​​that define the tread pattern height over the entire or partial outer surface of the tire (e.g., a 3D profile).

[0027] As used herein, the “remaining service life” of a particular tire refers to the remaining wear as a function of parameter values ​​that affect the tire’s lifespan. These influencing parameters include the load, pressure, temperature, and tread pattern height of the particular tire. The remaining service life can be determined continuously, at regular predetermined intervals, or at sporadic intervals by collecting data corresponding to the parameters that affect the service life of a particular tire. The collected data can be used as the basis for the method of the present invention that defines the current wear state of a tire in order to determine the remaining service life of a particular tire.

[0028] More specifically, the estimation method of the present invention is a pseudo-slip stiffness K X This is based on the estimation of temperature as an influencing parameter in the determination of the pseudo-slip stiffness K. X This is calculated from data transmitted from the vehicle and slip, and is intended to give the tread pattern height of each tire.

[0029] This calculation uses the pseudo-slip stiffness K. X This allows us to proceed from the tread pattern height and is also called the "transfer function F". Obtaining the transfer function F is achieved through a characterization operation that includes numerical simulations and experimental measurements.

[0030] This transfer function F is the pseudo-slip stiffness K of an assembly ("mounted assembly" is understood to mean an assembly consisting of a tire, brake, and wheel) mounted on the same reference road surface being evaluated. XThese evaluations require that various influencing parameters be varied on the exact same road surface by means of moving the vehicle or trailer or other mounting assembly, or on a test stand. Similarly, these evaluations can be numerically simulated by modeling the exact same reference road surface for each evaluation. This second option is low-cost when it is necessary to realize the transfer function F for the entire dimensional range of the tire model or for various components of the mounting assembly. It should be understood that it is also possible to combine the two types of characterization to validate the numerical model for a specific tire size or mounting assembly. In that case, this characterization can be numerically extended for the entire dimensional range of the tire or for the deformation of the structural components of the mounting assembly.

[0031] The method for obtaining this transfer function F is fully described in the applicant's International Publication No. 2020 / 120923. As disclosed, the transfer function F is obtained using the following type of mathematical model: JPEG2026519859000004.jpg13170 Here, M j 0 and h ref is a constant, α j And α is a real number, M j These are influencing factors. h represents the height of the tread pattern.

[0032] The form of this transfer function is suitable for aligning experimental results. For example, it can handle a wide range of values ​​for a set of influencing parameters, rather than being limited to the nominal position region through a limited development. Furthermore, since the influencing parameters are independent of each other in this case, it becomes easier to identify the parameters of the transfer function F. Finally, this transfer function focuses on the interaction with a single road surface, a reference road surface mounting assembly.

[0033] The influence of road surface properties must be considered using the transit function β as an indicator. The pseudo-slip stiffness K for the connection between this mounting assembly and various road surfaces. X The sensitivity is considered to be incorporated only into the passage function β. The selected index relates to the mounting assembly, in particular its interaction with the road surface, which is expressed by the stiffness of the tire tread, a structural element of the tire that contacts the road surface. The passage function β relates to the road section characterized by geographical location (e.g., represented by GPS data(s)). Pseudo-slip stiffness K of the mounting assembly X Since the sensitivity of this quantity β is known to depend on the road surface properties, tire condition, and estimates of the actual road surface properties of the road section, it should be understood that an inclusion function can be used for this quantity β. Considering the interaction between the road surface and the mounting assembly is an important factor in determining the quality of the tread pattern height h.

[0034] The acquisition of the pass function β is also disclosed in the applicant's International Publication No. 2020 / 120923 and comprises the following steps: - A step of performing a series of measurement cycles related to various sections of dry road in an identical state cycle of the mounting assembly; - For each measurement cycle, the steps include obtaining a first pseudo-slip stiffness on the actual road surface and a second longitudinal pseudo-slip stiffness on the reference road surface; - For each measurement cycle, the step of obtaining the difference X between the first and second pseudo-slip stiffnesses; - A step of defining a target measurement cycle by identifying the measurement cycle that minimizes the difference X from a set of measurement cycles; and - A step of assigning an identity function to a defined passage function β for the road section related to the target measurement cycle.

[0035] Here, the term "measurement cycle" is understood to mean that the mounting assembly is under the same operating conditions with respect to parameters such as expansion pressure P, temperature T, and load Z. The term "same conditions" should be understood to mean that changes in these parameters during the measurement cycle are not significant relative to the average values ​​of these parameters over the entire measurement cycle. Furthermore, the tread pattern height h, and any other influencing parameters related to the state of the mounting assembly, are assumed to remain unchanged throughout the same measurement cycle. Specifically, the measurement cycle has a duration far shorter than the duration required to observe changes in the state of the mounting assembly.

[0036] The term "mounting assembly state cycle" is understood to mean that the influence parameters of the second group H remain constant throughout the entire cycle. In contrast, the parameters of the first group G, which are related to usage, may change throughout this entire cycle.

[0037] In the estimation method 100 of the present invention, tire wear is estimated based on the determination of the tread thickness E of a particular tire. This thickness E is determined according to the following type of mathematical model: JPEG2026519859000005.jpg13170 The transfer function F of this model includes at least the expansion pressure P, temperature T, load Z, and tread thickness E as influencing factors. First pseudo-slip stiffness K X actual and the second pseudo-slip stiffness K X ref This relates to the determination of the thickness E. In this embodiment of the method of the present invention, the force F X At least one slip ratio g%, load Z, expansion pressure P, and temperature T are determined as described above.

[0038] Those skilled in the art will understand that the performance of a tire is consequently influenced by its condition. The condition of a tire is primarily determined by the liner temperature, inflation pressure, remaining tread pattern height, and the load level supported by the tire. Therefore, knowledge of these parameters, whether direct or indirect, is essential for analyzing tire performance and determining wear and other performance parameters (including, but not limited to, grip, rolling resistance, and / or durability).

[0039] The estimation method 100 of the present invention is - An identification step to identify the tires of an assembly attached to a vehicle; - An acquisition step to obtain a passage function β defined by the road section and the tire tread stiffness; - The transfer function F of the mounting assembly is given by the pseudo-slip stiffness K on the reference road surface. X The acquisition step involves obtaining the following: the inflation pressure P, temperature T, and load Z of a specific tire, as well as influencing parameters including the tread pattern height h; In a predetermined measurement cycle, - At least one force F acting on the mounting assembly when the vehicle is traveling in a straight line with changes in acceleration on a dry road section. X A determination step of determining at least one slip ratio g% at the wheel center of the mounting assembly; - A step of determining the load that the mounting assembly will receive under driving conditions; - A step of determining the temperature of the mounting assembly under driving conditions; - The step of determining the expansion pressure of the internal cavity of the mounting assembly under driving conditions; The temperature is characterized by being determined according to the following type of mathematical model: JPEG2026519859000006.jpg10156 Here, T amb i The initial temperature is in Kelvin, and Pf Tamb f and Pi Tamb iThese are, respectively, the pressures at the end and beginning of a predetermined distance for a particular tire of an assembly mounted on a particular vehicle.

[0040] This model was validated over realistic usage cycles of "highway," "main road," and "urban road" types. Referring again to the figures, Figure 3 shows an example of a tire temperature simulation curve over five realistic cycles. Figure 4 shows an example of a simulation curve for the average rise in tire temperature over three types of realistic usage cycles. Figures 3 and 4 show examples of simulation curves for a mounting assembly consisting of one of the following tires: - Michelin brand tires from the Primacy4 RT series (size 205 / 55R16); - Michelin brand tires from the CrossClimate+ series (size 205 / 55R16); - Pilot Sport 4 Series with Michelin brand tires (size 225 / 45R18) - Pilot Sport 4 Series with Michelin brand tires (size 225 / 45R18) (wear condition)

[0041] The assumptions underlying this model are as follows: - The laws of ideal gases can be applied. - Between the time the pressure is measured at the start of the simulation process and the time the pressure is measured at the end of the process, no air is lost from or introduced into the tire cavity. - The initial pressure is assumed to be measured with the internal air temperature equal to the ambient temperature (therefore, the mounting assembly, including the tire, wheel, and cavity, is in thermal equilibrium with the ambient temperature as a whole).

[0042] Figures 3 and 4 show that simulations under realistic cycles demonstrate that tire temperature changes continuously during driving as a result of stress and ambient temperature changes throughout the cycle. Therefore, it can be concluded that under actual usage conditions, tires are always in a thermal transient state. An average tire thermal transient state certainly exists, and its amplitude depends on the type of cycle (highway cycle, trunk road cycle, city road cycle).

[0043] The following parameters were carried over in the simulation: - Tire load: From 40% to 100% of the ETRTO load, in 5% increments. - Starting pressure ("initial pressure"): From 1.8 to 2.8 bar, in 0.1 bar increments. - Speed: From 30 to 150 km / h, in 10 km / h increments. - Ambient temperature: -10°C to +40°C, in 10°C increments.

[0044] Each simulation was conducted under specific conditions (load, speed, temperature, etc.). The tires followed the recommended inflation and load conditions specified in the European Tire and Rim Technology Organization (ETRTO) Standards Manual 2020 - Commercial Vehicle Tyres. The compression and shear deformation of the raised elements that divide the tread pattern affect the pressure on the road surface and, consequently, wear.

[0045] It is proposed that there is a correlation between the internal air temperature of a tire and the tire's stabilization temperature. It is generally known that the tire temperature is higher than the temperature of the rim on which the tire is mounted. Furthermore, the surface area between the tire and its internal air is far greater than the surface area between the internal air and the rim.

[0046] By constructing a model that determines the temperature of tires on an assembly mounted on a specific vehicle, the following conclusions can be drawn from the simulation: - Ambient temperature is essential in the model. - The average model across all four tires yields virtually identical results to the individual tire-specific model. - It appears that two variables are needed from the three pairs of variables Fz and V (Pi, PF, Tair).

[0047] The assumption made in the simulation is that the initial pressure corresponds to an internal air temperature equal to the ambient temperature. Using the law of ideal gases (PV=nRT), it appears clear that the ambient temperature and the stabilized internal air temperature are strongly correlated with the initial pressure and the stabilized final pressure.

[0048] In this specification, the term “specific tire” (singular or plural) refers to a tire mounted on a specific vehicle (a tire still in use on a specific vehicle). A specific tire may be equipped with one or more known sensors to generate or capture data such as data corresponding to the operating environment of a specific vehicle or part thereof. These sensors may include a set of sensors for providing data on the operating characteristics of a specific tire. The sensors may include, for example, one or more speed sensors, one or more acceleration sensors, one or more sensors related to traction, one or more sensors related to braking, and / or a combination of sensors for collecting data on one or more conditions of the dynamic condition of a specific tire. These sensors may also provide stored data relating to the identification of a specific tire, including, but not limited to, its place of manufacture, place of distribution and / or storage location, date of manufacture, retread history where applicable, and mounting location and history.

[0049] In some embodiments, the sensor is of a type that provides temperature and pressure measurements of the mounting assembly. These sensors can be selected from TMS ("tire mounting sensor") type sensors that are positioned along the crown on the inner liner of a particular tire so that the sensor is located approximately in the center plane of the tire. The load on the mounting assembly is applied using a cylinder on a test stand or a vertical force F applied by a power measuring hub. Z, as well as the longitudinal component F X and axial component F Y The measurement is taken by the applied vertical force F. Z This is done using coercive force by controlling the rotation axis of the mounting assembly. The change in torque around the rotation axis of the mounting assembly is applied to the wheel center of the mounting assembly via the test stand. The applied torque is measured using a power measuring hub. Furthermore, an encoder mounted between the stator and rotor of the rotation axis of the test stand measures the position of the rotation axis of the mounting assembly relative to the road surface, and similarly measures the rotational speed of the wheel center of the mounting assembly. Finally, the movement on the road surface is also controlled by machine.

[0050] Various parameters of the mounting assembly need to be determined in a short time corresponding to the measurement cycle. Any prior art means that can meet this constraint can be used. Accordingly, pressure and temperature measurements can be obtained by direct or indirect sensors using conventional methods. For example, a pressure sensor communicating with the fluid inside the mounting assembly directly measures the expansion pressure. For example, a temperature sensor for the fluid contained in the internal cavity indirectly measures the temperature of the mounting assembly (especially the tire tread pattern). It is necessary to use a thermal model that considers heat exchange in various heat transfer modes (radiation, convection, conduction) between various components (internal fluid, components of the mounting assembly, and external fluid). Of course, measurement by thermocouples installed in the tire is a more direct temperature measurement, but it is difficult to implement because it requires structural modification of the tire casing.

[0051] In some embodiments, these sensors are selected from sensors implemented in an electronic system fixed to a mounting assembly (e.g., a TPMS (Tire Pressure Monitoring System) attached to the valve) or TMS fixed to the inner wall of the tire that partitions the internal cavity.

[0052] More direct measurements of the mounting assembly can also be envisioned. For example, by calibrating a periodic signal with each wheel rotation, it becomes possible to extract the longitudinal dimension, which represents the contact characteristics between the tire casing and the road surface for a given mounting assembly. In this case, a sensor sensitive to the radial and / or longitudinal deformation of the tire (e.g., an accelerometer or piezoelectric sensor) is envisioned. By using a chart between this characteristic dimension and the expansion pressure, it becomes possible to work back and evaluate the load on the mounting assembly. It should be understood that other equivalent devices can also be used.

[0053] Pseudo-slip stiffness K X Another characteristic evaluated in the determination is the slip ratio G% of the mounting assembly at the wheel center. This variable can be directly estimated from data provided by the vehicle's electronic system (e.g., the ABS system). It can also be evaluated through three basic parameters: the rotational speed of the mounting assembly at the wheel center, the turning radius of the mounting assembly, and the forward speed of the vehicle.

[0054] The rotational speed can be easily obtained by a wheel rotation encoder connected to a clock. The rolling radius of the mounting assembly, which is less sensitive to wear, is obtained through the vehicle's travel distance and the number of rotations the mounting assembly made to travel this distance. Finally, the vehicle's forward speed is obtained by a high-frequency measuring device (e.g., RT3000 type) to ensure sufficient accuracy.

[0055] Finally, the overall tire wear is assessed in real time by determining the parameters of the mounting assembly substantially simultaneously, although these parameters are the pseudo-slip stiffness K of the mounting assembly. X These are the usage conditions that affect the performance, and perhaps the condition parameters of the mounting assembly, especially the tires, which are determined over a longer period of time. In detail, the influence of road surface properties must be considered by an index (i.e., a passing function β).

[0056] To implement the method of the present invention by computer, a system is provided comprising at least one communication network (or "Network") for managing input data coming into the system from various sources (e.g., from at least one TMS-type or TPMS-type device). The communication network incorporates one or more communication servers (or "Servers"), each having one or more processors operationally connected to memory. The memory is configured to store an application for analyzing data representing the operational characteristics of a particular tire. The one or more processors comprises modules for executing the analysis application and can execute program instructions stored in memory to carry out the steps of estimation method 100.

[0057] The data entering this system that implements the estimation method may include general information about a particular tire. This general information includes, but is not limited to, stored data relating to the identification of a particular tire (including its place of manufacture, place of distribution and / or storage, date of manufacture, retread history where applicable, and mounting location and history). Corresponding data for a particular tire may be maintained by an entity that manages the use of one or more vehicles fitted with the same type of tire (for example, such an entity may include one or more individuals and / or one or more companies) and / or the manufacturer of such tire.

[0058] The term “processor” (or, instead, the term “programmable logic circuit”) means one or more devices that are capable of processing and analyzing data and that have one or more software packages for processing such data (e.g., one or more integrated circuits, one or more controllers, one or more microcontrollers, one or more microcomputers, one or more programmable logic controllers (PLCs), one or more application-specific integrated circuits, one or more neural networks, and / or one or more other known equivalent programmable circuits). The processor comprises one or more software packages for processing data taken in by a system implementing an estimation method, and further comprising one or more software packages for identifying changes, locating them, identifying their causes, and correcting them.

[0059] In a system implementing the method of the present invention, memory may include both volatile and non-volatile memory devices. Non-volatile memory may include solid memory such as NAND flash memory or keep-alive memory (or KAM) for storing various operating variables while the processor is off, magnetic storage media and optical storage media, or any other suitable data storage device that retains data when the system (and / or equipment incorporating the system) is shut down or loses power. Volatile memory may include static RAM and dynamic RAM for storing program instructions and data, including learning applications.

[0060] The processor may also refer to a reference (e.g., a lookup table of various tire sizes) to ultimately determine one or more parameters of a particular tire. The reference may include known tire parameters corresponding to multiple available known tires. A tire reference may include measurements corresponding to multiple available tires. For example, in the case of a tire with size 225 / 50R17, the number "225" specifies the tire's cross-sectional area in millimeters, the number "50" indicates the sidewall aspect ratio, and the measurement "R17" represents the rim diameter in inches (which is approximately 43.18 centimeters).

[0061] Further details of embodiments relating to the estimation method 100 of the present invention are given by reference to the figures, particularly Figure 2. The estimation method is implemented in at least one processor of a system that performs the estimation method 100.

[0062] As used herein, the terms “method” or “process” may comprise one or more steps performed by at least one computer system having one or more processors for executing instructions to perform the steps. Unless otherwise specified, any order of steps is provided as an example and does not limit the described methods to any particular order.

[0063] At the start of the method of the present invention, the estimation method 100 includes an identification step 102 to identify a mounting assembly comprising a particular tire. This step can be performed by assigning identifiers to the components of the mounting assembly that relate to the vehicle in a database. During this step, the identification of the mounting assembly makes it possible to define characteristic tread pattern heights (e.g., tread pattern height when the tire is new, tread pattern height at the end of the tire's lifespan, etc.).

[0064] The estimation method 100 further includes a selection step 104 to select a passage function β from a list of possible passage functions β that represent the central characteristics of the road section that the vehicle will encounter. The identification of the mounting assembly performed in step 102 makes it possible to know the tread stiffness of the tire, thereby allowing one or more passage functions β to be estimated from several possible passage functions, each relating to a road section characterized by macroroughness.

[0065] Estimation method 100 further includes the pseudo-slip stiffness K. X The procedure includes a selection step 106 to select a transfer function F that associates the tread pattern height h with the tread pattern height h. Identification of mounting assemblies performed during step 102 also makes it possible to select a transfer function F for the corresponding mounting assembly, whose influencing parameters are represented by load Z, pressure P, temperature T, and tread pattern height h.

[0066] The estimation method 100 further includes an investigation step 108 for examining the aging condition of a particular tire. This step utilizes the identification information of the mounting assembly (performed during the identification step 102) to determine the usage history of the particular tire. This history can be obtained by querying one or more databases (an external database, a database located on the vehicle, or a database located on the server(s) of the system running the estimation method 100). If the aging condition of a particular tire is related only to the product's years of service, total number of cycles achieved, or mileage, this information may be present on the mounting assembly via an electronic device (e.g., a TMS or TPMS device). This step 108 is performed during a condition cycle that includes a measurement cycle for evaluating the average thickness of the tire.

[0067] Estimation method 100 further includes the force F measured at the wheel center of the mounting assembly. X This includes an acquisition step 110 to obtain the associated slip ratio G%. This step is performed during straight-line driving on a dry road, including acceleration and deceleration phases. A direct force F is applied to the wheel center.X If it does not exist, accessing the characteristics of a specific vehicle will allow you to access the force F at the wheel center. X (For example, the torque applied to the wheel center around the natural axis of rotation of the mounting assembly during acceleration or deceleration phases) can be estimated.

[0068] The estimation method 100 further includes an acquisition step 112 to obtain usage parameters of the mounting assembly. These acquired parameters may include the inflation pressure P, the temperature T of the mounting assembly's tires, and the applied load Z (or specific vehicle characteristics that enable the acquisition of load Z, including but not limited to the static mass of the tires, the fuel tank fill level, and the number of tightened seat belts). This step 112 must be performed immediately before, during, or after the straight-line driving performed in the preceding step or step 110.

[0069] In one embodiment of estimation method 100, the acquisition step 112 for obtaining the usage parameters of the mounting assembly comprises the following steps: - A step of determining the load that the mounting assembly will experience under driving conditions; - A step of determining the temperature of the mounting assembly under driving conditions; and - A step of determining the expansion pressure of the internal cavity of the mounting assembly under driving conditions.

[0070] In this embodiment, the temperature is determined according to the following type of mathematical model: JPEG2026519859000007.jpg9156 Here, T amb i The initial temperature is in Kelvin, and Pf Tamb f and Pi Tamb i These are the pressures at the end and beginning of a predetermined distance for a particular tire, respectively.

[0071] Estimation method 100 further involves two pairs (F XThis step includes plotting a point cloud related to the force F measured or evaluated while driving on a dry road section. X This is performed based on the relevant slip ratio g%. During this step, only the set of points in this point cloud where the tire does not slip on the road section is retained. Finally, a linear regression line is identified for the retained set of points. The slope of this regression line is the first pseudo-slip stiffness K for the actual road surface corresponding to the dry road section. X This corresponds to the estimated value. It should be understood that this step can be performed between two measurement cycles.

[0072] The estimation method 100 further provides the transfer function F obtained in step 104 with the usage parameters measured in step 112 (e.g., reference conditions Z, P, and T) and the tread pattern height h obtained in step 102 to obtain a second pseudo-slip stiffness K. X This includes an estimation step 116 for estimating the following. Depending on the sensitivity of the mounting assembly's properties to aging degradation, this step may also be linked to step 108 in which the aging degradation of the mounting assembly is evaluated.

[0073] The estimation method 100 further includes step 118, which evaluates the average tread pattern height of a particular tire, and thus the overall wear of the tire, by comparing this evaluated average height with the specific height of the tire (e.g., the tread pattern height when the tire is new and when the tire is at the end of its lifespan). For this purpose, the relationships between the results of steps 104, 110 and 112 are applied, and the result is the average thickness h related to the condition cycle of a particular tire. Second pseudo-slip stiffness K X If the transfer function β (obtained in step 116) is defined using the transfer function F (obtained in step 106) as described above, then this transfer function is the product of power functions of the independent influence parameters. As a result, the tread pattern height h can be separated from this transfer function F. In this case, we assume that the transit function β is constant with respect to the average tread pattern height.

[0074] The estimation method 100 further includes an acquisition step 120 to acquire the change ΔU of a parameter U related to the use of a particular tire during two acquisitions of the average tread pattern height. The parameter U can be, for example, the number of rotational cycles around the natural axis of rotation, the mileage of the tread, or the usage time of a particular tire. The two acquisitions of the average tread pattern height (h1, h2) can be, for example, two evaluations performed by the method corresponding to two wear states of a particular tire, an evaluation of the average tread pattern height in combination with the new state of a particular tire, or measurement of the average height of a particular tire using external measuring means.

[0075] The estimation method 100 further includes an evaluation step 122 for evaluating the wear rate of a particular tire. This step includes evaluating the tread at the point when the average tread pattern height of the particular tire is obtained. For this, both the change ΔU of a parameter U related to the use of the particular tire (obtained in the preceding step 120) and the corresponding change Δh of the average height are required. The change Δh represents the difference between two acquisitions (h1, h2) that served as reference points for the change ΔU in the preceding step 120. The ratio of the change Δh of the average height to the change ΔU of the parameter ΔU related to the tire use defines the wear rate of the average tread pattern height according to the parameter U.

[0076] The estimation method 100 further includes a final evaluation step 124 for evaluating the remaining service life of a particular tire. This step involves evaluating the end-of-life prediction according to a parameter U related to the use of the particular tire. This prediction is obtained by combining the results of the identification step 102, the evaluation step 118 for evaluating the average tread pattern height, and the evaluation step 122 for evaluating the wear rate of the particular tire.

[0077] The estimation method 100 of the present invention can be performed under the control of a PLC and may include pre-programmed management information. For example, the adjustment of the method may relate to the parameters of a particular tire, the parameters of a mounting assembly incorporating a particular tire, and / or the characteristics of a vehicle intended to be fitted with a particular tire. A system implementing the estimation method 100 of the present invention (and / or equipment incorporating this system) can easily repeat one or more steps of the estimation method 100 in a predetermined order.

[0078] A system implementing the estimation method 100 of the present invention (and / or equipment incorporating this system) may include pre-programmed management information. For example, the adjustment of the method may be related to the parameters of a typical vehicle in which the system operates. In some embodiments of the present invention, a system implementing the estimation method 100 of the present invention (and / or equipment incorporating this system) may receive voice commands or other voice data representing, for example, commands to start or stop the method. The generated response may be represented auditorily, visually, tactilely (e.g., by using a tactile interface), and / or virtually and / or augmentatively. This response may be related to corresponding data and recorded in a neural network.

[0079] A surveillance system can be implemented in all embodiments of this system. At least a portion of the surveillance system can be installed in a portable device such as a mobile network device (e.g., a mobile phone, a laptop computer, one or more portable devices connected to a network (including "augmented reality" devices and / or "virtual reality" devices), a wearable device connected to a network, and / or any combination thereof and / or any equivalent).

[0080] In one embodiment, the estimation method 100 of the present invention may include a step of training a system to recognize values ​​representing tread pattern height (e.g., the inner and outer diameter values ​​of a particular tire when it is new) for comparison with a target value (e.g., a value of tread pattern height related to a corresponding known service life). Each training step may include classifications generated by a self-learning means. These classifications may include, but are not limited to, the parameters of the mounted tire, the vehicle configuration, the expected service life of a particular tire, and the expected values ​​at the end of the estimation method in progress.

[0081] It should be noted that several different learning methods are possible, including supervised learning (the algorithm is trained on a labeled dataset and learns until it achieves the desired result), unsupervised or semi-supervised learning (the data is not labeled so that the network can learn in order to improve the accuracy of the algorithm), reinforcement learning (the algorithm is rewarded for positive results and punished for negative results), and active learning (during learning, the algorithm requests examples and labels to refine its predictions) (see https: / / www.lebigdata.fr / reseau-de-neurones-artificiels-definition).

[0082] The terms "at least one" and "one or two or more" are used interchangeably. A range presented as "between a and b" encompasses the values ​​"a" and "b".

[0083] While specific embodiments of the disclosed apparatus have been illustrated and described, it should be understood that various changes, additions, and modifications are possible without departing from the spirit or scope of this disclosure. Therefore, no limitations should be imposed on the scope of the described invention, except as disclosed in the attached claims. [Explanation of symbols]

[0084] 100 start 102 Identify the mounting assembly. 104 Select the passing function β 106 Select the transfer function F 108 Check the condition of tires due to age-related deterioration. 110 Obtain force and slip ratio G% 112 Obtain wear parameters 114 Actual K X To estimate 116 Reference condition: K X Z, P, T 118. Evaluate the average tread pattern height. 120 Obtain the change amount ΔU 122 Evaluate the wear rate 124. Evaluate the service life.

Claims

1. An estimation method (100) for estimating the tread pattern height of a particular tire of an assembly mounted on a particular vehicle under driving conditions, wherein the tire has a crown extended by two sidewalls terminating at two beads, exhibiting rotational symmetry about a natural axis of rotation, the crown having a tread located radially outward of the tire with respect to the natural axis of rotation, the tread having an average tread pattern height h, the method is implemented in at least one processor of a system performing the estimation method (100), the at least one processor comprising an analysis application module to which data representing the operating characteristics of the particular tire is applied, and the method An identification step (102) to identify the tire of the assembly attached to the vehicle, A selection step (104) of selecting a passage function β from a list of passage functions β that may represent the central characteristics of the road section that the vehicle will encounter, wherein the selection step (104) enables the estimation of one or more passage functions β, each relating to the road section and the stiffness of the tread of the tire, The transfer function F of the mounting assembly is given by the pseudo-slip stiffness K on the reference road surface. X A selection step (106) to select between the following influencing parameters represented by load Z, pressure P, temperature T, and tread pattern height h, In a predetermined measurement cycle, When the vehicle is traveling in a straight line on a dry road section with changes in acceleration, at least one force F is exerted on the mounting assembly. X The determination step (110) is to determine the slip ratio G% of at least one slip ratio at the wheel center of the mounting assembly, An acquisition step (112) for acquiring the usage parameters of the mounting assembly, A step of determining the load (Z) that the mounting assembly receives under driving conditions, A step of determining the temperature (T) of the mounting assembly under driving conditions, A step of determining the expansion pressure (P) of the internal cavity of the mounting assembly under driving conditions, The acquisition step (112) includes, Includes, The temperature is of the following types: It is characterized by being determined according to the mathematical model of, where T amb i The initial temperature is in Kelvin, and Pf Tamb f and Pi Tamb i A method in which the pressures are, respectively, at the end and beginning of a predetermined distance for a particular tire.

2. The tread thickness E of the aforementioned specific tire is of the following type: Determined according to the mathematical model of, The transfer function F of the mathematical model comprises at least the expansion pressure P, temperature T, load Z, and the thickness E of the tread as influencing factors. The first pseudo-slip rigidity K of the mathematical model X actual and the second pseudo-slip rigidity K X ref are related to the determination of the thickness E, and the estimation method (100) according to claim 1.

3. The estimation method (100) according to claim 1 or 2, further comprising an investigation step (108) for examining the state of age-related deterioration of the particular tire, wherein, during the investigation, identification information of the mounting assembly is used to determine the usage history of the particular tire.

4. The force F measured while driving on a dry road section X A plotting step (114) is performed based on the aforementioned slip ratio G%, wherein during the plotting step, the first pseudo-slip stiffness K is determined for the actual road surface corresponding to the dry road section. actual The plotting step (114) yields an estimated value, The second pseudo-slip stiffness K is obtained by applying the usage parameters measured in the acquisition step and the tread pattern height h obtained in the selection step to the transfer function F obtained in the selection step (106). ref Estimation step (116) to estimate, The estimation method (100) according to claim 2, further comprising:

5. The estimation method (100) according to any one of claims 1 to 4, wherein the passage function β is selected from a plurality of possible passage functions in a list of passage functions β that may represent the central characteristics of the road section that the particular vehicle will encounter.

6. The estimation method (100) according to any one of claims 1 to 5, further comprising an evaluation step (118) of evaluating the average tread pattern height by comparing it with the specific height of the particular tire.

7. The estimation method (100) according to claim 6, further comprising an acquisition step (120) of acquiring a change ΔU of a parameter U related to the use of the particular tire between two acquisitions of the average tread pattern height.

8. The estimation method (100) according to claim 7, further comprising an evaluation step (122) for evaluating the wear rate of the particular tire, wherein the evaluation step (122) includes a step of evaluating the tread at the time the average tread pattern height of the particular tire is obtained.

9. The evaluation step (124) includes evaluating the remaining service life of the particular tire, wherein the evaluation step (124) includes evaluating the end-of-life prediction according to the parameter U relating to the use of the particular tire. The estimation method (100) according to claim 8, wherein the lifespan prediction is obtained by combining the results of the identification step (102), the evaluation step (118) for evaluating the average tread pattern height, and the evaluation step (122) for evaluating the wear rate of a particular tire.

10. A system comprising a communication network for managing data representing the operating characteristics of a particular tire based on an assembly attached to a specific vehicle under driving conditions, wherein the communication network comprises at least one communication server that executes program instructions stored in the memory of one or more processors of the system in order to implement the method according to any one of claims 1 to 9.

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