Method for controlling the driving control systems of a land vehicle

Abstract

The invention relates to a method for optimizing the control of a vehicle's driving control system, said vehicle (2) comprising at least one tire constituting a mounted assembly, comprising the following steps: Obtaining tire identification; Obtaining a usage parameter for the mounted assembly including the tire; Obtaining a model of a functional parameter of the mounted assembly that is a function of the usage parameter; and Modifying the control of the vehicle's driving control system by updating the control algorithm using the model of the functional parameter obtained. Figure for the abstract: Fig. 3

Description

Title of the invention: Method for controlling the driving control systems of a land vehicle Field of invention

[0001] The present invention relates to the field of driving land vehicles, and in particular to electronic systems for assisting the driving of vehicles in the context of the development of autonomous driving. Technological background

[0002] Land vehicles and in particular private vehicles are increasingly electronically assisted to compensate for failures or errors on the part of human beings and thus ensure increased safety on the roads. If the first steps were aimed at occasional dangerous situations which may arise for example in emergency braking conditions or delicate driving conditions on low-grip surfaces through AD AS systems (acronym in English for Advanced Driver Assistance Systems) such as ABS (acronym in English for Anti-lock Braking System) or ESP (acronym in English for Electronic Stability Program), electronic driver assistance is now increasingly widespread with a view to autonomous driving of vehicles, that is to say in the absence of a human driver or with minimal attention from the latter.In addition, the automation of actions by electrical or electronic control systems also tends to reduce the impact of the human factor on the operation of the vehicle or by substituting human actions with objective responses obtained by physical means possibly coupled with artificial intelligence.

[0003] However, one of the most influential factors on the behavior of the vehicle when moving lies in the tire which performs various functions such as carrying the load, guiding the vehicle, moving the vehicle while ensuring an acceptable noise level for the occupants, but especially for those living near the vehicle. Due to its connection to the ground, it allows essential functions to be performed, but it must also guarantee the controlled maintenance of this connection with the ground. However, the tire is a technically complex component due to its structure and composition, the interactions of which are multiple and diverse.As a result, vehicle driving assistance systems, whether for vehicle guidance, propulsion or braking, or even more specific functions such as energy recovery during vehicle deceleration phases for propulsion using electric motors, require a good understanding of this essential component of land vehicles.

[0004] Furthermore, the tire is neither universal nor constant over time. Indeed, its structure and composition give it different abilities from one individual to another and which evolve with its aging or wear. Although we seek to standardize the general behavior of the tire, which makes it possible to adjust the driving assistance systems in a unique way, guaranteeing increased safety for the vehicle's occupants, the tires do not necessarily give the best of themselves and the assistance systems do not take advantage of all the potential that the tire contains. Thus, the fact of adapting the vehicle's driving systems to the tire equipping said vehicle has emerged. However, several disadvantages then emerge.How to ensure that the full potential of the tire is taken advantage of at every moment of its usage cycle and that a physical change of the vehicle's tire does not affect the operation of the vehicle and, above all, the safety of its occupants.

[0005] The objects of the invention which follow aim to resolve these problems, that is to say to guarantee having the best of the tire equipping the vehicle with the aim of optimizing the driving systems of the vehicle by taking advantage of the full potential of the tire. Description of the invention

[0006] The invention relates to a method for optimizing the control of at least one driving control system of a land vehicle, said vehicle comprising at least one tire constituting a rolling assembly of the vehicle, comprising the following steps: • Obtain at least one identification of at least one tire of the vehicle; • Obtain at least one usage parameter of the rolling assembly including at least one identified tire, • Obtain at least one model of a functional parameter of the mounted rolling assembly which is a function of at least one usage parameter of the mounted assembly, • Modify the control of at least one vehicle driving control system by updating the control algorithm and / or the input data of the at least one vehicle driving control system using the at least one model of the functional parameter obtained.

[0007] The first step is to obtain the identity of the tire in order to determine its transfer function through functional parameter models of the latter. This makes it possible to update the control algorithms of the electronic systems of the vehicle's driving. To ensure that the identity of the tire is exact, it is possible, for example, to multiply the types of tire identification media in the vehicle. Then the redundancy of the same identification information offers a level high level of confidence in the identity of the tire, which is particularly sought for the functions of driving control systems with a safety aspect. This identification phase can take place when the vehicle is stopped with an identified periodicity, at each stop, every week, every month, but it can also take place while driving, at the request of the vehicle, for example each time it is started.

[0008] The third step consists of obtaining the functional parameter model(s) of the mounted assembly comprising the tire identified in the previous step. This functional parameter model, when limited to the tire, is provided by the tire manufacturer, who guarantees the accuracy of the transfer function represented by the model. Thus, the tire, which is a technically complex product, is modeled by a certain number of mathematical equations that represent a photograph of the tire that is as faithful as possible to the physical object from the tire manufacturer's point of view. This photograph of the tire may be available, like other tire photographs, directly on the vehicle, for example through a dedicated memory space. To avoid errors in selecting photographs, each photograph of the tire is associated with the identity of the tire.These models are mathematical equations whose variables directly or indirectly include a usage parameter of the mounted assembly. Generally, the functional model of the mounted assembly is similar to a complex mathematical model of the tire that is associated with a simple model of the wheel. Indeed, the wheel can simply be modeled by a non-deformable solid having only inertial properties, a global mass and inertias in two or three main directions. Here, the term usage parameter is understood to mean a physical quantity that the mounted assembly, therefore the tire, undergoes independently of the tire's response. For example, the inflation pressure of the mounted assembly to which the tire belongs is imposed by the operator who controls or adjusts the inflation pressure of this mounted assembly.Inflation pressure is a usage parameter of the mounted assembly that is imposed on it and that can change over time due to natural gas exchanges between the mounted assembly and the exterior of the mounted assembly and depending on the inflation maintenance applied to the tire. Similarly, vehicle settings, such as the distribution of the total mass of the vehicle between the various mounted assemblies, i.e. the static load Z imposed vertically on each tire, are usage parameters of the tire since they are constraints imposed by the vehicle. Depending on the vehicle's usage conditions, the behavior or response of the tire is influenced. And the mathematical model is a representation of the evolution of the behavior of the mounted assembly, and of the tire in particular, to these usage parameters. Good. Of course, a functional parameter of the assembled assembly can also depend on another functional parameter of the assembled assembly, knowing that in the end they all depend directly or indirectly on usage parameters. As a result, the link with the step of obtaining a usage parameter is implicitly established.

[0009] Advantageously, the method comprising a step of determining the state of the tire of the mounted rolling assembly defining at least one usage parameter, obtaining at least one model of a functional parameter of the mounted rolling assembly takes into account at least one usage parameter defined by the state of the tire.

[0010] As mentioned in the preamble, the tire is a complex product whose behavior changes over time due to changes in its condition. The condition of the tire is firstly controlled by its wear. Indeed, given its use, the tire is in a condition of friction or sliding on the ground, which gradually alters its surface condition at the level of the tire tread. This leads to wear of the tire which results in a reduction in the thickness of the tire tread. For a passenger tire, the circumferential hollow of the tire tread generally varies between 8 millimeters in its new condition up to 1.6 millimeters which corresponds to its legal threshold of use according to certain regulations.This reduction in the thickness of the tread affects the behavior of the tire by disrupting, for example, the distribution of the total mass of the tire between the crown of the tire where the tread is located and the sidewall of the tire which undergoes different wear than that of the tread. Similarly, the tire undergoes physicochemical attacks during its use on the vehicle, which alters its initial structure; it is the effect of time and use which results in the aging of the tire. This deterioration of the structure of the tire, which is not necessarily homogeneous over the entire tire, affects the structure of the tire, which leads to a change in its thermomechanical behavior. Of course, the aging of the tire differs depending on the use of the tire, but also on the geographical area where it is operated.The condition of the assembled assembly corresponds to that of the tire because the evolution of the tire is faster than that of the wheel of the assembled assembly.

[0011] Taking into account tire wear and / or tire aging as a usage parameter is advantageous in order to take advantage of the tire's full potential by controlling its general condition at all times.

[0012] Advantageously, the method comprises a step of determining the nature and / or state of the ground where the vehicle is located, defining at least one usage parameter, obtaining at least one model of a functional parameter of the assembled assembly takes into account at least one usage parameter defined by the nature and / or condition of the ground.

[0013] Thus, the characteristics of the ground where the tire rolls and therefore the mounted assembly are characteristics imposed by the road on the tire, these evolve according to the nature of the ground, that is to say its structural composition, but also according to the state of the ground, its water level for example. Beyond the impact of the ground on the evolution of wear or aging of the tire, the ground constitutes one of the environments external to the tire with which the tire will interact through the contact zone of the tire with the ground called the contact patch. As a result, the behavior of the tire will be influenced by the ground by modifying, for example, the distribution of the dynamic stresses exerted by the ground in the contact area which represents the thermomechanical exchange zone between the two environments, the tire and the ground.For example, on a ground with high macroroughness, the total surface in direct contact between the tire and the ground is smaller than on a smooth ground. Therefore, at the same load carried by the tire, the surface, directly in contact between the two media, is different, which implies different stress amplitudes. In conclusion, the nature of the ground influences the behavior of the tire at the level of the contact zone between the tire and the ground, which can modify more or less strongly the general mechanical behavior of the tire depending on the functional quantities of the tire that we observe.

[0014] In addition, the condition of the ground, which is mainly characterized by its water level for asphalt or bituminous soils, changes according to climatic conditions. The presence of water on the roadway modifies the nature of the contact between the ground and the tire by the presence of this third medium. Thus, the behavior of the tire is transformed by the presence of water, and this according to the quantity of water actually present. Therefore, taking into account the condition of the ground is interesting to take this characteristic into account in the functional parameter models of the mounted assembly which are influenced by this characteristic, such as those linked to the contact area.

[0015] According to a preferred embodiment, the determination of the identification of the at least one tire comprises at least the reading of a device containing the individual identification of the tire according to a standard such as the SGTIN-96 standard.

[0016] The identification of the vehicle tire can be done by reading the information reproduced on the outer sidewall of the tire. However, this identification is not closely linked to the individual, but to a group of individuals having a certain number of common characteristics. However, the interest of an individual identification is to be able to have reliable information on the state of the individual tire with regard to its aging and wear. The best way to obtain individual tire identification is to use a standard such as SGTIN-96 (an acronym for Serialized Global Trade Identification Number coded on 96 bits). This standard allows obtaining information on the product at the level of the product type, but especially of the individual. In addition, this coding is of reasonable size, which allows it to be transported on various identification media such as a QR code (an acronym for Quick Response) or an electronic device such as an RFID tag (an acronym for Radio Frequency IDentification) or a TPMS (an acronym for Tyre Pressure Monitoring System).

[0017] Preferably, the device containing the individual identification of the tire being electronic, the reading of the device is carried out by radiofrequency communication.

[0018] If an identification device is a visible marking, a deterioration of the surface condition of the tire can lead to poor identification of the tire or an inability to read the identification medium. Radiofrequency communication overcomes these reading problems from the moment when the identification medium cannot be damaged during use of the tire. TMS type solutions (acronym in English for Tyre Mounted System) are also conceivable as an identifier medium, in the same way as a TPMS, however the solution of an RFID tag buried in the structure of the tire is ideal insofar as the integration is ensured, in all cases, by the tire manufacturer and by the fact that it is standardized (ISO20909).In fact, these devices will transmit the identification of the tire they contain in their memory as long as the device is operational without identification errors as in the case of optical reading. The RFID tag is ideal, because it is potentially without energy source which gives it almost infinite autonomy.

[0019] Very preferably, the electronic device comprising at least one electronic component included in the group comprising an electronic chip, a sensor, a microprocessor, the step of reading the electronic device comprises obtaining at least one unique identifier of the at least one electronic component.

[0020] All electronic devices need at least one electronic chip to function like the RFID tag. They can also be equipped with other electronic components such as a measuring sensor such as a pressure and / or temperature sensor or a radiofrequency transmitter coupled to a microprocessor. Each industrially produced electronic component has a unique identifier that allows it to be identified individually.

[0021] By ensuring both the reading of the individual identifier of the tire by the reading of a standard and reading of the individual identifier of the electronic identification device by reading the unique identification of at least one component of the identification device, the level of integrity of the information or security containing the identity of the tire is reinforced by a verification indicating that the two identifiers are indeed linked since the manufacture of the tire. Thus, it is no longer necessary to multiply the identification media to ensure the true identity of the tire. This is possible as long as the tire manufacturer or seller has previously associated the identity of the tire with that of a part of the identification device.

[0022] According to a second preferred embodiment, obtaining at least one functional parameter model of the rolling assembly comprises querying a database comprising the at least one functional parameter model.

[0023] Preferably, the database being remote from the vehicle, the interrogation of the database is done via the radiofrequency communication means located on the vehicle, preferably the radiofrequency communication between the database and the vehicle is secure.

[0024] Obtaining the functional parameter model of the mounted assembly requires querying a database authenticated by the tire manufacturer or seller who associates the identity of the tire with the generation of a functional parameter model thereof. Of course, associating the identity of the tire with the identity of a component of the identification medium reinforces the security of the functional parameter model provided by the database.

[0025] This database is located at the vehicle level after having been transferred to it by specific means of communication. It can also be relocated from the vehicle and can then be interrogated remotely through the vehicle's means of communication. Concretely, only the transmission of the functional parameter models of the identified mounted assembly is carried out. Ideally, the transmission is secured in order to ensure the veracity of the data of the functional parameter model. If the functional model of the tire takes into account the state of the tire, it is appropriate to neutralize at the level of the vehicle driving control systems the functional parameter model of the mounted assembly in its previous state so as not to invert the models.

[0026] Advantageously, the at least one model of the functional parameter of the mounted assembly comprises a mathematical formula comprising as variable the at least one usage parameter of the mounted assembly.

[0027] Very advantageously, the at least one model of the functional parameter comprises an application range comprising at least one range of values ​​of the at least one usage parameter of the mounted assembly.

[0028] The functional parameter model of the mounted assembly comprising the identified tire consists of a mathematical formula expressing a functional parameter of the mounted assembly as a function of one or more usage parameters of the identified mounted assembly. In most cases, the mathematical formula provided is valid over a more or less wide range of values ​​of one or more usage parameters of the identified tire. The functional parameter model must then contain both the mathematical formula, but also the ranges of values ​​which define its scope of validity. These mathematical formulas are for example the equations of functional models of the tire such as the Tametire models or the Magic Formula formulas or the PACEJKA model.

[0029] Preferably, the functional parameters of the mounted rolling assembly are included in the group comprising the rigidity of the mounted assembly which are at the origin of the generation of forces and moments at the wheel center, the shape of the contact surface of the tire of the mounted rolling assembly with the ground, the hollow of the tread of the tire.

[0030] Here, functional parameters of the mounted assembly are understood to mean output quantities of the transfer function of the mounted assembly supplied by usage parameters of the mounted assembly. An output quantity of the transfer function is a quantity which evolves according to the conditions of use of the mounted assembly represented by the structural dimensions of the tire, the inflation pressure, the static load applied, according to the conditions of use of the tire on the vehicle represented by the static and dynamic adjustments of the ground connection, according to the characteristics of the ground represented by the texture of the ground, its nature, its water level and according to the state of the tire through its wear and aging. The mathematical formulas of Magic Formula or Pacekja models relate approximately 15 functional parameters of the mounted assembly.Tametire's mathematical formulas, integrating thermal exchanges at the tire level but also the description of the contact area, include around 20 functional parameters.

[0031] According to a specific embodiment, the method comprises the additional steps during rolling of the vehicle: • Determination of at least one usage parameter of at least one mounted rolling assembly of the vehicle; • Activate the at least one vehicle driving control system in response to the input of the at least one usage parameter determined during vehicle driving in the control algorithm of the at least one vehicle driving control system.

[0032] In vehicle driving condition, the method is completed by a first step determining the tire usage parameters. These tire usage parameters can be tire usage parameters or tire condition characteristics or specificities on the ground where the vehicle is traveling. The acquisition of these usage parameters makes it possible to identify the functional parameter models of the assembled assembly that are to be used. These are then loaded into the vehicle driving control systems. Finally, these vehicle driving control systems are activated before ensuring appropriate behavior of the vehicle to its occupants, guaranteeing both the greatest comfort and the best efficiency of the potential of each tire in the context of vehicle driving.

[0033] Preferably, the determination of at least one usage parameter of the mounted rolling assembly comprises at least the acquisition of data from at least one measuring device of the vehicle.

[0034] Certain tire usage parameters can be obtained in a lump sum, such as the nature of the ground on which the tire is rolling. These parameters can, for example, also be provided by consulting information on maps or by accessing public information such as weather reports. However, it is entirely possible to obtain the tire usage parameters through a measurement using a device present on the vehicle or one of its components. Thus, the inflation pressure can be obtained through a TPMS type sensor mounted on the valve of the rim of the mounted assembly of which the identified tire is a part. Similarly, obtaining the tire's rolling speed can be obtained by estimating the vehicle's travel speed provided by a GPS system (acronym in English for "Global Positioning System").In order to put the vehicle's driving control system into action, certain usage parameters must be actually measured in order to constitute a lock for the activation of these optimized control systems.

[0035] Very preferably, the at least one measuring device of the vehicle is included in the group comprising an electronic device provided with a sensor and located on a mounted assembly of the vehicle comprising the determined tire, a device for spectral analysis of the vibroacoustic level recorded by at least one microphone and / or at least one accelerometer, a device for analyzing the optical interferences emitted by a Gaussian and coherent light source.

[0036] Thus, information at the mounted assembly level is envisaged to collect for example the inflation pressure or the temperature of the fluid cavity of the mounted assembly opposite a pressure and temperature sensor mounted on the mounted assembly such as a TPMS or a TMS. Similarly, the accelerometric measurement along the radial direction of the tire at the crown block allows to estimate the static load applied, the rotation speed or the mileage traveled by the tire. And a vibroacoustic measurement on the vehicle, in particular near the tire, allows, through spectral analysis of the measurement and artificial intelligence tools, to trace back to the characteristics of the ground in terms of nature and condition at least in the form of a more or less reduced family class, but also to characteristics on the condition of the tire in terms of wear level always in the form of a more or less precise class. Finally, using a coherent light source and differentiated optical paths, it is possible to trace back to the nature of the ground in terms of PMT (acronym for Mean Depth of Texture) by interferometric analysis of the light signals.Thus, access to the tire usage parameters at the level of the assembled assembly, the vehicle settings, the ground and the general condition of the tire are entirely possible. These measurements can take place in real time on board the vehicle or off-board if a channel for transmitting the raw measurement data can be envisaged.

[0037] The invention also relates to a system for implementing the method for optimizing the control of a system for controlling the driving of a land vehicle comprising - A land vehicle equipped with at least one mounted assembly comprising a pneumatic envelope, the at least one mounted assembly being equipped with an identification support for said pneumatic envelope, preferably the identification support is an electronic device communicating by radio frequency; - Said vehicle comprises a means of reading the identification medium, preferably a means of radiofrequency communication; - Said vehicle comprises a memory space capable of storing at least one functional parameter model of the mounted assembly equipped with the identification support; - Said vehicle comprises means for obtaining usage parameters of the assembled assembly; and - Said vehicle comprises at least one vehicle driving control system using a steering algorithm, the steering algorithm being supplied by at least one functional parameter model of the mounted assembly.

[0038] This is a particular configuration where the vehicle includes all the elements for implementing the identification of the mounted assembly, the supply by the correct model of functional parameters of the mounted assembly in order to supply the vehicle driving control system. This is particularly useful for updating the vehicle driving control system for parameters that change quickly such as the condition or nature of the ground on which the vehicle is driven. Otherwise, if the usage parameter of the assembled assembly only takes into account the condition of the tire, identification over longer time intervals corresponding for example to vehicle maintenance visits to garages may be sufficient. Obtaining the condition of the tire and its identifier can then be carried out by devices external to the vehicle through optical means for example. Brief description of the drawings

[0039] The invention will be better understood on reading the following description, given solely by way of non-limiting example, and made with reference to the appended figures in which the same reference numbers designate identical parts throughout and in which: • [Fig.l] presents a perspective view of a part of the system for implementing the method for optimizing the control of a vehicle driving control system according to the invention; • [Fig.2] shows a perspective view of another part of the system for implementing the method for optimizing the control of a vehicle driving control system according to the invention; • [Fig.3] presents a synopsis of the method for optimizing the control of a vehicle driving control system according to the invention; • [Fig.4] shows a model of a functional parameter of the assembled assembly according to the condition of the tire; • [Fig.5] presents a model of a functional parameter of the assembled assembly according to the nature of the ground on which the vehicle rolls; Detailed description of the embodiments

[0040] [Fig.l] shows a perspective view of a part of a system for implementing the method for optimizing the control of a system for controlling the driving of a land vehicle. In particular, the vehicle is equipped with a device 3 for reading electronic objects in a transport vehicle 2 of the motor vehicle type.

[0041] The motor vehicle 2 is here represented by a transparent volume representing the closed equipped dressed body which corresponds to the complete vehicle from which the axles and the powertrain have been removed. However, on this vehicle 2, four cavities denoted 21a-l, 21a-2, 21b-l and 21b-2 are visible, each capable of receiving a mounted assembly of the vehicle. The mounted assembly here comprises radiofrequency devices of the TMS sensor type (acronym in English for Tyre Mounted Sensor) at the level of the pneumatic casing or TPMS (acronym in English for Tyre Pressure Monitoring System).

[0042] This vehicle 2 also includes the reading system 3 allowing communication with the radiofrequency devices of the mounted assemblies, but it could communicate with radiofrequency devices of the vehicle located near the reading system 3. This reading system 3 comprises a first device for transmitting and reading electrical signals 31 installed in the vehicle 2 at the level of the apron, which is a wall mainly vertical relative to the ground where the vehicle moves, delimiting the compartment, generally the engine, of the vehicle located at the front of the vehicle 2 of the passenger compartment. This device 31 therefore comprises the transmitter of electrical signals, but also the electrical signal demodulator.

[0043] From this device 31, two bidirectional communication cables 32a and 32b depart towards the left and right sides of the vehicle 2 respectively. These communication cables are traveling wave cables and are mounted on the device 31 in order to constitute a galvanic connection. Each cable 32a, 32b runs through the structure of the vehicle 2 in order to reach the proximity of at least one cavity 21a-1, 21a-2, 21b-1, 21b-2 for receiving the mounted assemblies. Each cable comprises a signal transmission part from the device 31 and then becomes radiating.

[0044] In fact, as illustrated in [Fig.l], each cable 32a, 32b reaches the proximity of two receiving cavities of the mounted assemblies each corresponding to the front axle and the rear axle of the vehicle 2. At the first cavity 21a-1, the cable 32a has a continuous portion 32a-1 which is continuous located at the wheel arch, describing an angular sector around the axis of the front axle of 120 degrees. This portion 32a-1 of the communication cable 32a is located in the communication zone of the radiofrequency devices of the mounted assembly to be received in the cavity 21a-l. Thus this portion 32a-1 of the communication cable 32a will communicate with the radiofrequency devices of the mounted assembly present in the receiving cavity 21a-l. Here, the continuous portion 32a-1 of the cable is located radially outside the mounted assembly.

[0045] However, the same cable 32a then extends towards the second receiving cavity 21a-2 located on the left side of the vehicle 2 at the rear axle. At this cavity 21a-2, the cable 32a has a second continuous radiating part 32a-2 located in the communication zone of the radiofrequency devices of the mounted assembly to be received in the cavity 21a-2. The second continuous and radiating part 32a-2 extends angularly around the axis of rotation of the rear axle over an angular sector of 90 degrees. Indeed, the rear axle is not directional here and consequently the mounted assembly moves little angularly during the rolling phase.Consequently, the radio frequency communication between the continuous and radiating part 32a-2 of the bidirectional communication cable 32a is facilitated compared to that of the part 32a-1 where the axle is directional generating an angular movement of the assembly mounted in a turn for example. These two parts. 32a-1 and 32a-2 continuous and radiating are disjoint and each only allows communication with one mounted assembly. However, in the case of a twin-wheel axle as in the case of a utility vehicle in traction mode, the continuous part 32a-2 located near the cavity 21a-2 would allow communication with the various twin mounted assemblies, located on the same axle and on the same side of the vehicle 2.

[0046] Similarly, due to the symmetry of the motor vehicle 2, the communication cable 32b comprises a radiating part having two separate continuous parts each communicating with a mounted assembly located respectively on the front axle and the rear axle.

[0047] The total length of the bidirectional communication cable 32a and 32b does not exceed 5 meters here. The length of the continuous and radiating part 32a-1, 32a-2, 32b-1 and 32b-2 is greater than 50 centimeters, corresponding to a quarter of the development of a pneumatic envelope for a private vehicle. This length is beyond the unit length of the cable for radiofrequency communication in UHF at 433 MHz or 2.4 GHz which are communication frequencies of TPMS or TMS systems.

[0048] The transport vehicle 2 also comprises a system for controlling the driving of a land vehicle, such as, for example, the steering system of the mounted assemblies of the steering axle of the vehicle 2, which is controlled by steering algorithms. These steering algorithms take into account models of functional parameters of the various mounted assemblies of the vehicle 2, such as, for example, the drift rigidity Ky of the mounted assembly in the case of the steering system of the mounted assemblies of the steering axle according to the steering wheel angle. These models of functional parameters are stored in a memory space of the vehicle driving control system.

[0049] Certain models of functional parameters of the mounted assembly are a function of the state of the tire casing of the mounted assembly when the state of wear or aging of the tire casing influences the functional parameter of the mounted assembly, this is the case for example of the longitudinal rigidity Kx of the mounted assembly. The choice of the functional parameter model naturally depends on the identity of the tire casing. However, the functional parameter of the mounted assembly can also depend on the state of the tire. This second information can be contained in the electronic devices of the vehicle or those of the mounted assembly. For example, the age of the tire which is an indicator of its state of aging can be obtained by interrogating the memory of an electronic device previously containing this information.

[0050] However, the condition of the pneumatic casing as well as its state of wear can also be provided by a direct or indirect wear measurement carried out during the life of the tire casing. At that time, the measurement and the date of the measurement or even the temporal evolution of the wear of the tire makes it possible to estimate at any time the state of wear of the tire. Here, indirect measurement of tire wear means the mileage traveled by the tire casing. Knowledge of the mileage history and certain points of direct measurement of the wear of the tire makes it possible to deduce, from the mileage traveled by the tire casing, an estimate of the wear of the tire for constant use of the tire casing during its life.

[0051] These direct or indirect measurements can be data coming from measuring devices on the tire itself through TMS type devices for example which can provide information on the number of rotations actually carried out or estimated by the tire.

[0052] They can also be delivered by measuring devices on the vehicle 2. For example, the vehicle 2 can be equipped with a microphone in one of the cavities housing the mounted assemblies. This microphone records the vibroacoustic level prevailing in the cavity. Depending on the speed of movement of the vehicle, the type of pneumatic envelope of the mounted assembly and its condition, the sound level obtained, in its spectral representation, makes it possible to estimate the nature and condition of the ground on which the vehicle is moving. Here, the nature and condition of the ground are identified according to a summary metric. For example, the nature of the ground is representative of the PMT (acronym for Mean Depth of Texture) which provides information on the level of macroroughness of the ground. Similarly, the condition of the ground makes it possible to distinguish the ground according to 3 main categories which are dry ground, damp ground or wet ground.The differentiation between wet and damp ground is the height of the water on the ground relative to a reference plane of this ground, for example, the average plane resting on the upper ends of the ground. But more precise measurements can also be obtained through, for example, optical interferometry devices using a Gaussian and coherent light source such as a laser diode. These measurements make it possible to characterize more precisely the PMT of the ground where the tire rolls.

[0053] Finally, these measurements can also come from devices external to the vehicle such as measuring systems in professional locations such as car garages. The data is then transmitted to the vehicle by querying a database remote from it. The vehicle must then be equipped with radiofrequency communication means allowing the exchange of information with this remote database.

[0054] [Fig.2] shows a section of a pneumatic tire 100, which is also a pneumatic casing, comprising a crown S extended by two sidewalls F and ending with two beads B. In this case, the tire 100 is intended to be mounted on a wheel which is not shown in this figure, at the level of the two beads B in order to create a mounted assembly. A closed cavity is defined, containing at least one fluid under pressure, delimited both by the second radially inner surface 130 of the tire 100 and by the outer surface of the wheel. The tire 100 also comprises a first surface 140 radially outer of the tire 100.

[0055] The reference axis 201 will be noted corresponding to the reference axis or natural axis of rotation of the tire 100 and the median plane 211, perpendicular to the reference axis 201 and equidistant from the two beads B. The intersection of the reference axis 201 by the median plane 211 determines the center of the tire 200. A Cartesian reference will be defined at the center of the tire 200 consisting of the reference axis 201, a vertical axis 203 perpendicular to the ground and a longitudinal axis 202 perpendicular to the other two axes. And, we will define the axial plane 212 passing through the reference axis 201 and the longitudinal axis 202, parallel to the ground plane and perpendicular to the median plane 211. Finally, we will call vertical plane 213, the plane perpendicular to both the median plane 211 and the axial plane 212 passing through the vertical axis 203.

[0056] Any material point of the tire 100 is uniquely defined by its cylindrical coordinates (Y, R, 0). The scalar Y represents the axial distance to the center of the tire 200 in the direction of the reference axis 201 defined by the orthogonal projection of the material point of the tire 100 onto the reference axis 201. A radial plane 214 will be defined making an angle 0 relative to the vertical plane 213 around the reference axis 201. The material point of the tire 100 is identified in this radial plane 214 by the distance R to the center of the tire 200 in the direction perpendicular to the reference axis 201 identified by the orthogonal projection of this material point onto the radial axis 204. The unit vector perpendicular to the radial plane 214 and forming a direct trihedron with the unit vectors of the axial 201 and radial 204 directions represents the circumferential direction of the tire 100.

[0057] This tire 100 has on the radially inner surface 130 a fixing device present on the surface 130 by gluing according to the usual techniques of the state of the art when the fixing device is made of elastomeric material. The fixing device is fixed at the top S of the tire casing 100, which improves its endurance since the fixing device thus positioned provides less worry during the operations of mounting or dismounting the wheel on the tire casing 100. Indeed, the fixing device is located in an area remote from the beads B of the tire casing 100. Here, the fixing device is equipped with an electronic member 10 within its open volume which constitutes a housing adapted to receive the electronic member 10. As a result, the pneumatic casing 100 is here ready to be mounted on a wheel to constitute a mounted assembly. The electronic member 10 can deliver various functions such as the identification of certain components such as the electronic member 10 itself and the tire 100. But the electronic member 10 can also be equipped with a pressure and / or temperature sensor in order to evaluate the inflation pressure of the mounted assembly 100. Finally, it can also be equipped with a sensor directly measuring the curvature of the pneumatic casing 100 such as an accelerometer or a flexometer making it possible to trace usage quantities of the pneumatic casing such as the angular speed, the mileage traveled, the static load applied.All of these quantities make it possible to identify the performance of the pneumatic casing 100, such as, for example, its wear, its grip or intrinsic quantities of the ground on which the pneumatic casing 100 rolls. Thus, the mounted assembly equipped with its pneumatic casing 100 can be mounted on the vehicle of [Fig. 1].

[0058] The presence of the electronic member 10 within the pneumatic casing 100 provides a means of acquiring usage parameters of the assembly mounted within the mounted assembly itself. The electronic member 10 here is equipped with radiofrequency communication means allowing it to emit radio waves encoding identification, measurement or results data to the vehicle through the reading device illustrated in [Fig. 1].

[0059] [Fig.3] is a block diagram of the method 1000 for optimizing the control of a system for controlling the driving of a land vehicle.

[0060] This method 1000 comprises a first step 1001 corresponding to obtaining the identification of a tire casing of a mounted assembly of the vehicle, the mounted assembly being in a position capable of moving the vehicle. This obtaining of the identifier requires a step 1005 of reading the identification medium of the tire casing. It may be an optical device capable of reading graphic elements on the vehicle, preferably on the mounted assembly and very preferably on the tire casing such as a QR code, a bar code or regulatory markings. It may also be a radiofrequency communication device whose communication frequency is adapted to listen to a radiofrequency device arranged at the level of the mounted assembly such as an RFID tag or a TPMS or TMS type measuring sensor.

[0061] The second step of the method 1000 consists of obtaining a usage parameter of the identified mounted assembly, i.e. comprising the tire identified in step 1001, which corresponds to step 1002. In particular, this usage parameter may be a parameter on the state of the tire, which corresponds to step 1006. then by the condition of the tire, the level of wear of the tire and / or its level of aging. Indeed, the thermomechanical behavior of a tire generally depends on its state of wear and aging. Taking these into account is important in the choice of the mathematical model best representing the assembled assembly. But the usage parameter can also be the condition and / or the nature of the ground on which the assembled assembly rolls, which corresponds to step 1007.

[0062] The condition of the ground is understood to mean its hydrometric level, which corresponds to the quantity of water present on the roadway. Generally, the condition of the ground is classified into three categories: dry, humid and wet when the water is in liquid form. The differentiation between "humid" and "wet" is determined by the height of water present below a plane resting on the greatest asperities of the ground. A ground is described as humid when the height of water is below this plane resting on the ground. And conversely, it will be described as "wet" if the water is present above this plane. This therefore also indirectly depends on the roughness of the ground. The "wet" category can also be subdivided by defining subcategories using a metric associated with the height of water above the support plane, vertically to it.

[0063] The nature of the ground is understood here to mean the level of roughness of the ground in the dry state, taking into account only the roughness of the road. Generally, the nature of the ground is classified in terms of roughness using a metric which is the PMT (acronym for Mean Depth of Texture). Two boundaries are delimited corresponding to a PMT of 0.4 and 1.1. When the measured PMT is less than 0.4, the ground is described as smooth, the roughnesses are of low magnitude. When the PMT is greater than 1.1, the ground is described as rough, there are large and high roughnesses. Finally, when the PMT is between 0.4 and 1.1, the ground is described as average. The PMT measurement can be made by indirect measurement by analysis of the vibroacoustic level emitted by the mounted assembly of the vehicle for example. It can also be carried out by optical measurements using optical interferometry between an incident light beam and a beam reflected by the ground.The initial beam is provided by a Gaussian and coherent source such as a laser diode.

[0064] Then, the method 1000 comprises a third step 1003 which consists of obtaining a functional model of the mounted assembly which is a function of a usage parameter. In particular, this usage parameter is the state of the tire from step 1006 or the nature and state of the ground from step 1007. However, it can also depend on other usage parameters such as the inflation pressure, the temperature of the fluid cavity, the load carried Z by the mounted assembly. To identify the correct functional parameter of the mounted assembly from among all the available functional models, it is appropriate to combine this usage parameter with the parameter tire identification. It would be appropriate to take into account the geometric characteristics of the assembled assembly such as the diameter at the rim seat, the width of the rim, the width of the wheel rim, the nature of the wheel, or even the type of attachment of the tire to the rim. The various mathematical models of functional parameters can either be present on the vehicle through a memory space, or they are downloaded from a server remote from the vehicle using the vehicle's means of communication. This second option corresponds to step 1008 of the method 1000. Of course, it is possible to download a part of the mathematical models per period to have only the models associated with the state of the tire on the vehicle. The more the choice of functional parameters on the vehicle is reduced, the faster the detection of the correct mathematical model, which makes the method 1000 more fluid.

[0065] Finally, the method 1000 comprises a step of feeding the functional parameter obtained at the level of the vehicle driving control system. This electrical, mechanical or electromechanical system is controlled by an algorithm using functional parameters of the mounted assembly and possibly usage parameters of the mounted assembly. If the usage parameters are direct quantities associated with the mounted assembly such as the inflation pressure, the temperature of the mounted assembly, the load carried by the mounted assembly, the wear or age of the tire, the condition and nature of the ground, the functional parameters are the photograph of the mounted assembly defined by the usage parameters of the mounted assembly. This photocopy is an image of the mounted assembly at a given time which must be as faithful as possible to the mounted assembly.Updating the functional parameters of the mounted assembly allows the vehicle's driving control system to be provided with the most accurate and faithful image of the mounted assembly at any time. The accuracy of these functional parameters of the mounted assembly allows the vehicle's driving control system to be optimized in order to make the best use of the mounted assembly and in particular the tire, which guarantees better and optimized operation of the vehicle.

[0066] [Fig.4] shows the evolution of a functional parameter of the assembled assembly as a function of the level of wear of the tire. Thus, four tires from the same manufacturing batch therefore have the same dimensions, but also the same constituents of the same age. Three of these have undergone uniform planing of their tread on differentiated heights ranging from the new height hi to the wear threshold Hf. The planings have finally made it possible to produce four tires having the same aging, but having a tread depth at the level of the tread ranging from the regulatory wear indicator to the new height by constant step between these two extreme states. This is a method classically used in the tire industry to obtain tires of varying wear with identical aging.

[0067] Then, these tires were mounted on similar wheels to form mounted assemblies inflated to an identical inflatable pressure adapted to the requirements of the ETRTO (acronym in English for European Tire and Rim Technical Organization). Then each mounted assembly was mounted on the same test machine alternately.

[0068] This test machine comprises a measuring hub equipped with wheel center force cells making it possible to obtain the tensor of the forces and moments generally at the wheel center. This hub is driven by a movement using a tire drift device. A camber angle can also generally be applied to the mounted assembly, but this is not the subject here. Here, the drift angle is understood to mean the angle formed by the median plane of the mounted assembly relative to the direction of travel of the tire defined by the speed vector of the mounted assembly. After a pre-rolling phase, a cycle of evolution of the load carried Z by each mounted assembly was launched. For each stabilized load carried Z, a progressive drift angle δ was applied to the mounted assembly around the zero angle.In parallel with this drifting of the mounted assembly, a measurement of the transverse force FY at the wheel center of the mounted assembly, i.e. in the direction of the natural axis of rotation of the mounted assembly, was recorded. For each applied load Z, a curve of the transverse force FY is obtained as a function of the drift angle ô. The tangent at the origin of this curve is called Drift stiffness, is generally called DY and is expressed in Newton per degree noted N / °. The graph in [Fig.4] is the representation of these drift stiffnesses D(Z) obtained by changing the load carried Z. Although the same mounted assembly is represented here four times with the exception of its wear level due to the tread planing operation, significant differences in the drift stiffness D(Z) are visible as a function of tire wear. The maximum difference observed between a tire in new condition and its equivalent on the wear indicator is 70%.A drop in stiffness D(Z) is observed when the tire is worn at low loads. However, the curves can reverse at very high loads Z. Thus, curve 5001 in solid lines corresponds to the curve obtained with a tire in new condition in terms of wear whose tread depth is Hi. Curve 5002 formed by dark gray dashes corresponds to the drift stiffness D(Z) of a tire whose wear is approximately one third. The following curve 5003 formed by light gray dotted lines corresponds to two-thirds wear. Finally, curve 5004 formed by light gray dashes corresponds to a tire at its wear indicator which corresponds to a tread depth Hf. It should be noted that curve 5004 presents for low loads Z, a . greater rigidity due to the low tread height. But at higher loads, the 5004 curve stagnates and collapses more quickly than the stiffness curve of a new tire in terms of wear.

[0069] [Fig.5] shows the evolution of the same functional parameter of the assembled assembly as a function of another usage parameter of the assembled assembly, here the age of the tire. The figure therefore shows the evolution of the drift stiffness D(Z) for a tire having two different configurations. The first curve 6001 corresponds to a tire having been manufactured a few months before the test protocol was carried out, but whose state of wear is new, that is to say that the relative height of the hollows of the sculpture is at the maximum. While curve 6002 corresponds to the same model of tire from an older manufacture, a few years old, not having been driven during these years and whose level of wear can be considered as new. However, the behavior of elastomer materials varies with the passage of time outside of any mechanical stress, this is the effect of aging.

[0070] Of course, the two tires were mounted on similar wheels and inflated to the same pressure according to the ETRTO requirements. A differentiation is observed between the curves for the same load carried Z which reflects the differentiated behavior of the constituents of the tire for the same thermomechanical stress undergone. This differentiation is beyond the measurement dispersion of the test carried out for said tires, it is therefore significant.

[0071] Here, the aging of the elastomeric mixtures of the tire constituents tends to stiffen the material due to the elastomeric mixtures used. This results in an average load for an increase in rigidity of approximately 10%. Although this modification of drift rigidity of the mounted assembly is small, it remains in non-negligible orders of magnitude compared to modifications of rigidity associated with the state of wear of the tire casing. Therefore, its consideration is interesting for optimizing the mathematical model of this functional parameter of the mounted assembly in order to take advantage of the full potential of the mounted assembly of the vehicle in the vehicle driving control system.

Claims

Claims

1. Method for optimizing (1000) the control of at least one driving control system of a land vehicle, said vehicle (2) comprising at least one tire (100) constituting a mounted rolling assembly of the vehicle, comprising the following steps: - Obtaining at least one identification of the at least one tire of the vehicle (1001); - Obtaining at least one usage parameter of the mounted rolling assembly comprising the at least one identified tire (1002), - Obtaining at least one model of a functional parameter of the mounted rolling assembly (1003) which is a function of the at least one usage parameter of the mounted assembly, - Modifying the control of at least one driving control system of the vehicle (1005) by updating the control algorithm and / or the input data of the at least one driving control system of the vehicle using the at least one model of the functional parameter obtained.

2. Method for optimizing (1000) the control of a system for controlling the driving of a land vehicle according to claim 1, in which, the method comprising a step of determining the state of the tire (1006) of the mounted rolling assembly defining at least one usage parameter, obtaining at least one model of a functional parameter of the mounted rolling assembly takes into account at least one usage parameter defined by the state of the tire.

3. Method for optimizing (1000) the control of a system for controlling the driving of a land vehicle according to one of claims 1 to 2, in which the method comprises a step of determining the nature and / or the state of the ground (1007) where the vehicle is located, defining at least one usage parameter, obtaining at least one model of a functional parameter of the mounted assembly takes into account at least one usage parameter defined by the nature and / or the state of the ground.

4. Method for optimizing (1000) the control of a system for controlling the driving of a land vehicle according to one of claims 1 to 3, in which the determination of the identification of the at least one tire comprises at least the reading of a device (1005) containing the individual identification of the tire according to a standard such as the SGTIN-96 standard.

5. Method for optimizing (1000) the control of a system for controlling the driving of a land vehicle according to claim 4, in which, the device containing the individual identification of the tire being electronic, the reading of the device is carried out by radiofrequency communication.

6. Method for optimizing (1000) the control of a driving control system of a land vehicle according to claim 5, in which, the electronic device comprising at least one electronic component included in the group comprising an electronic chip, a sensor, a microprocessor, the step of reading the electronic device (1005) comprises obtaining at least one unique identifier of the at least one electronic component.

7. Method for optimizing (1000) the control of a system for controlling the driving of a land vehicle according to one of claims 1 to 6, in which obtaining at least one model of a functional parameter of the mounted rolling assembly comprises querying a database comprising the at least one functional parameter model.

8. Method for optimizing (1000) the control of a driving control system for a land vehicle according to claim 7, in which, the database being remote from the vehicle, the interrogation of the database is done via radiofrequency communication means (1008) located on the vehicle, preferably the radiofrequency communication between the database and the vehicle is secure.

9. Method for optimizing (1000) the control of a system for controlling the driving of a land vehicle according to one of claims 7 to 8, in which the at least one model of the functional parameter of the mounted rolling assembly comprises a mathematical formula comprising as variable the at least one usage parameter of the mounted assembly.

10. Method for optimizing (1000) the control of a system for controlling the driving of a land vehicle according to claim 9, in which the at least one model of the functional parameter comprises an application range comprising at least one range of values ​​of the at least a usage parameter of the assembled assembly.

11. Method for optimizing (1000) the control of a system for controlling the driving of a land vehicle according to any one of claims 1 to 10, in which the functional parameters of the mounted rolling assembly are included in the group comprising the rigidity of the mounted assembly which are at the origin of the generation of the forces and moments at the wheel center, the shape of the contact surface of the tire of the mounted rolling assembly with the ground, the hollow of the tread of the tire.

12. Method for optimizing (1000) the control of a driving control system of a land vehicle according to any one of claims 1 to 11, in which the method comprises the additional steps during a rolling of the vehicle: - Determining at least one usage parameter of at least one mounted rolling assembly of the vehicle; - Activating the at least one driving control system of the vehicle in response to the input of the at least one usage parameter determined during the rolling of the vehicle in the control algorithm of the at least one driving control system of the vehicle.

13. Method for optimizing (1000) the control of a system for controlling the driving of a land vehicle according to claim 12, in which the determination of at least one usage parameter of the mounted rolling assembly comprises at least the acquisition of data from at least one measuring device of the vehicle.

14. Method for optimizing (1000) the control of a driving control system of a land vehicle according to claim 13 in which the at least one measuring device of the vehicle is included in the group comprising an electronic device provided with a sensor and located on a mounted assembly of the vehicle comprising the determined tire, a device for spectral analysis of the vibroacoustic level recorded by at least one microphone and / or at least one accelerometer, a device for analyzing the optical interferences emitted by a Gaussian and coherent light source.

15. System for implementing the method (1000) for optimizing the control of a system for controlling the driving of a land vehicle according to one of claims 1 to 14 comprising: - A land vehicle (2) equipped with at least one mounted assembly comprising a pneumatic casing (100), the at least one mounted assembly being equipped with an identification support (10) for said pneumatic casing (100), preferably the identification support is an electronic device communicating by radio frequency; - Said vehicle (2) comprises a means of reading (3) the identification medium, preferably a means of radiofrequency communication; - Said vehicle (2) comprises a memory space capable of storing at least one functional parameter model of the mounted assembly equipped with the identification support (10); - Said vehicle comprises means for obtaining (10) usage parameters of the mounted assembly; and - Said vehicle comprises at least one vehicle driving control system (2) using a steering algorithm, the steering algorithm being supplied by at least one functional parameter model of the mounted assembly.

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