Method for estimating the load distributed over a trailer coupled to a vehicle

Abstract

Disclosed is a method for estimating the variation in the load carried by a mounted assembly on a trailer, the variation resulting from the trailer being coupled to the vehicle, the method comprising the following steps: coupling the trailer to the vehicle; recording the internal temperature T in the fluidic cavity of an equipped mounted assembly; ascertaining the internal pressure P in the fluidic cavity of the equipped mounted assembly using a specified law of change; evaluating a variation in the volume ΔV of the equipped mounted assembly by means of the recorded internal temperature T and the ascertained internal pressure P using a model of a fluid in adiabatic transformation, the fluid having a perfect gas behavior; and estimating a variation in the load ΔZ carried by the n equipped mounted assembly using a second function comprising, as a parameter, the evaluated intermediate variation in volume ΔV and the flattening stiffness of the tire of the mounted assembly per unit volume KP.

Description

DESCRIPTION TITLE: METHOD FOR ESTIMATING THE LOAD DISTRIBUTED ON A TRAILER COUPLED TO A VEHICLE Field of invention

[0001] The present invention relates to the field of real-time determination of the quasi-static load applied and in particular the load variation generated by the coupling of a trailer to a vehicle, in particular when the vehicle is stationary. Technological background

[0002] Obtaining the quasi-static load applied to a stationary trailer makes it possible to determine whether the trailer or each of the trailer's axles is in a safe condition before even setting it in motion, which makes it more reliable and allows for compliance with safe traffic conditions. Indeed, determining the load applied to inflatable systems such as mounted assemblies generally requires a balancing scale; it is not easy to determine this load outside of very specific loading locations such as quarries where the trailer is loaded when coupled to the vehicle. In order to evaluate, outside of these specific locations, the load carried by the trailer as well as by each axle of the trailer, it is possible to evaluate the load carried by each mounted assembly of the trailer through an indication of the tire's footprint on the ground.Although a measurement using a static pressure quantification system is possible by inserting the measurement system between the mounted assembly and the ground, its implementation is not simple and the accuracy of the measurement is subject to the correct positioning of the measurement system. Another alternative is to evaluate the dimension of the contact patch in rolling conditions by measuring the deformation of the tire at the wheel revolution in order to determine the dimension of the contact patch. Through a mathematical model, linking the type of tire, the inflation pressure and the external dimension of the footprint, we then go back to the load applied to the tire casing. Unfortunately, this measurement is in rolling conditions. As a result, the trailer may no longer be within its safe operating range at the time of the measurement.Furthermore, the accuracy of these measurements is delicate for very heavy loads where the deformation of the tire which determines the load variations tends to stabilize according to the circumferential direction on which the evolution of the measurement of the deformation of the tire envelope generally relates.

[0003] The following objects and methods of the invention aim to solve the problem of measuring the variation in load carried by the trailer in the absence of a measurement system external to the trailer, i.e. one that can be used at any time without specific measuring means. In addition, this evaluation is carried out while the vehicle is stationary, making it possible to decide on the safety criterion for loading the trailer before any movement thereof. Description of the invention

[0004] The invention relates to a method for estimating the variation in load carried by a mounted assembly of a trailer generated by the coupling of the trailer to a stationary towing vehicle comprising the following steps: • In the preliminary phase, i.e. before coupling the trailer to the vehicle • Equip at least one mounted assembly of at least one axle of the trailer not coupled to the towing vehicle with at least one temperature sensor, said sensor being capable of measuring the internal temperature of the fluid cavity of the mounted assembly delimited by a pneumatic casing and a wheel, preferably at least one mounted assembly of each axle of the trailer, very preferably all the mounted assemblies of all the axles of the trailer; • Determine the initial load ZI applied to at least one mounted assembly equipped with the unhitched trailer; • Determine the initial inflation pressure PI of at least one mounted assembly equipped with the trailer; • Determine the initial internal temperature Tl of at least one mounted assembly equipped with the trailer; • Evaluate the initial volume VI of at least one mounted assembly equipped using a first function comprising as parameter the volume V0 of the fluid cavity of the mounted assembly unloaded and inflated to the initial pressure PI and the flattening rigidity of the tire of the mounted assembly per unit of volume Kp • Evaluate the number of moles of fluid n in the fluid cavity of each assembled assembly equipped from a model taking into account the inflation pressure PI, the initial volume VI, the temperature Tl; and • Determine a law of evolution of the internal pressure P of the fluidic cavity from the internal temperature T during an adiabatic transformation for at least one assembled assembly, inflated and subjected to the load Zl, equipped with at least one temperature sensor; • In the main phase, • Attach the trailer to the vehicle at a point geometry M of the trailer; • Record the internal temperature T of the fluidic cavity of at least one mounted assembly equipped at an acquisition frequency Fl; • Determine the internal pressure P of the fluid cavity of at least one equipped mounted assembly using the evolution law determined in the preliminary phase; • Evaluate an intermediate volume variation AV of at least one equipped assembly using the determined internal pressure P and the internal temperature T measured using a fluid model in adiabatic transformation, the fluid having perfect gas behavior; and • Estimate a load variation AZ carried by each equipped assembly using a second function including as parameter the intermediate volume variation AV evaluated and the flattening rigidity of the tire per unit of volume Kp.

[0005] According to a preferred embodiment, in the preliminary phase, the at least one mounted assembly equipped with the at least one axle of the trailer comprising a pressure sensor capable of measuring the internal pressure of the fluid cavity, the method comprises, in the main phase, a step for recording the internal pressure P of the fluid cavity of the at least one mounted assembly equipped when, at least the recorded internal temperature T changes direction of variation or after a duration T0 corresponding to the end of the adiabatic transformation of the fluid and the method comprises a second step of evaluating the intermediate volume variation AV2 of the at least one mounted assembly equipped taking into account the recorded internal pressure P, the recorded internal temperature T corresponds to the period of recording the internal pressure P using a fluid model in adiabatic transformation, the fluid having a perfect gas behavior

[0006] The process of determining the variation of applied load comprises two successive phases. The first phase consists of identifying the intrinsic parameters of the mounted assembly before coupling the trailer to the vehicle. This constitutes an installation of the trailer measurement system through the implementation of the measurement systems at the trailer axles and the identification of the initial parameters of the mounted assemblies such as the volume of the fluid cavity, the quantity of fluid contained in the closed volume defined by the fluid cavity, the load initially applied to the mounted assembly by the uncoupled trailer, the internal temperature of the fluid cavity and the inflation pressure of the fluid cavity of each mounted assembly. Intuitively, the nature of the fluid is assumed to be known to estimate the quantity of fluid trapped in the fluid cavity.It is also necessary to have a law of evolution of the variation of internal pressure P associated with the variation of internal temperature T of the assembled assembly when it is in use condition, in particular at the load ZI carried around the inflation pressure PI and the temperature Tl. This law of evolution can be fixed or result from an experimental characterization or a numerical simulation of the assembled assembly considered.

[0007] The second phase represents the step of evaluating the load variation applied to each mounted assembly equipped with an electronic device due to the coupling of the trailer to the vehicle. The electronic device including the temperature sensor, manages and conditions T recordings of the internal temperature measurement of the fluidic cavity. Thus, recordings of the internal temperature of the fluidic cavity of each mounted assembly equipped with an electronic device are carried out at the time of Tcoupling of the trailer to the vehicle. The temporal evolutions, in transient phase, of the physical quantities of the fluidic cavity are important. The coupling of the trailer causes a first transformation corresponding to the work generated by this additional load which is similar to an adiabatic transformation, i.e. rapid which is preponderant in front of the second transformation.After the rapid transformation, a slower one follows, corresponding to the thermal equilibrium of the fluid cavity with the external environment through the tire and the wheel. This equilibrium is necessary following the modification of the internal temperature of the fluid cavity associated with the transformation linked to work. This thermal equilibrium is slower to be implemented due to the thermal inertia of the tire and the wheel. In addition, the thermal equilibrium is generally of smaller magnitude on the variation of volume of the fluid cavity than the transformation linked to work. Preferably, the electronic device is fixed on the internal wall of the tire. The tire is in fact the most deformable element during the adiabatic transformation. Thus, the temperature sensor being further away from the wheel, the relative temperature variations compared. at the absolute temperature measured are higher because the thermal inertia of the casing is lower and the wheel, especially the metal one, has by nature a greater inertia than that of the tire. As a result, this improves the accuracy of temperature measurement and therefore the quality of the load variation method.

[0008] Using the variation of the internal temperature T of the fluid cavity, it is possible to determine the variation of the internal pressure P of the fluid of the fluid cavity which is defined, for this purpose, by the evolution law previously determined in the preliminary phase. It therefore converts the measurement of the internal temperature of the fluid of the fluid cavity and an evaluation of the internal pressure of the fluid generated by the only transformation related to the work generated by the additional load applied.

[0009] Then, it is possible to evaluate a first intermediate volume variation using a fluid model undergoing an adiabatic transformation. Here, the term adiabatic means that the transformation that the fluid undergoes due to the coupling of the trailer to the vehicle is carried out without external heat exchange between the fluid cavity and the exterior of the mounted assembly, which assumes that it is rapid. Therefore, using only the variation of the measured internal temperature and the variation of internal pressure determined by the law of evolution from the variation of internal temperature of the fluid cavity, it is possible to estimate the first volume variation of the fluid cavity generated by the coupling of the trailer to the vehicle, the fluid having undergone an adiabatic transformation. We will make the entirely suitable assumption for air or nitrogen that the fluid, in the gaseous state, of the cavity of the equipped mounted assembly is an ideal gas.Of course, for this first evaluation of the volume variation corresponding to the adiabatic transformation of the fluid alone, it is appropriate to extract from the measured internal temperature variation only the changes associated with the adiabatic transformation. The end of the adiabatic transformation is characterized by a change in the internal temperature of the fluid cavity opposite to that of the adiabatic transformation. In addition, it is quite possible to estimate the duration T0 from which the adiabatic transformation of the fluid ends. Indeed, the event of coupling the loaded trailer to a vehicle is repeatable and reproducible, which makes it possible to set a duration T0 with precision and quality.

[0010] Preferably, a second intermediate volume variation is evaluated using a second fluid transformation. This second transformation is associated with the thermal equilibrium of the fluid with the exterior through the components of the mounted assembly, mainly the pneumatic envelope. The second volume variation is then evaluated undergone by the mounted assembly following this second transformation using a second variation of the internal temperature extracted from the initial recording of the internal temperature of the fluid cavity during the transient phase linked to the coupling of the trailer but subsequent to the adiabatic transformation, that is to say when the internal temperature of the fluid cavity changes its evolution compared to the adiabatic transformation. In addition, the internal pressure of the fluid cavity of the equipped mounted assembly is measured by having previously installed a pressure sensor in said mounted assembly. Here too, the variation in volume is defined by solving a differential equation whose input data are the measured internal pressure P and the measured internal temperature which is located at the end of the first transformation of the fluid.Taking this second volume variation into account ensures better accuracy in assessing the volume variation of the fluid cavity, which improves the accuracy of measuring the load variation at each equipped mounted assembly. However, the first intermediate volume variation is sufficient to estimate, to a first order of magnitude, the overload applied to the mounted assembly.

[0011] It is necessary through the method, in preferential mode, to dissociate in the measurement of the internal temperature T of the fluidic cavity, the first transformation of the fluid, that qualified as adiabatic, from the second transformation of this same fluid which corresponds to the thermal equilibrium of the fluidic cavity with the external environment through the pneumatic envelope and the wheel. For this, the recording of the internal temperature of the fluidic cavity can indicate to us the passage from the first transformation to the second transformation by a change in the evolution of the internal temperature of the fluidic cavity. Indeed, the overload of a mounted assembly leads to a heating of the fluid of the fluidic cavity during the adiabatic transformation.Then, due to the thermal inertia of the pneumatic casing and the wheel, the thermal equilibrium of the second transformation of the fluid will tend to decrease the temperature reached at the end of the adiabatic transformation. Conversely, a discharge of the mounted assembly leads to the expansion of the fluid in the fluid cavity which cools during the adiabatic transformation. The thermal equilibrium which follows will lead to an increase in the temperature of the fluid in the fluid cavity by the external environment which is assumed to be at the initial temperature of the fluid before the discharge of the mounted assembly, therefore the external temperature is higher than the internal temperature at the end of the adiabatic transformation.

[0012] Of course, taking into account the variation in the external temperature of the mounted assembly resulting from the thermal equilibrium of the mounted assembly also makes it possible to refine the measurement of the second variation in volume, generated by the coupling of the trailer to the vehicle, at level of each equipped mounted assembly. However, in a simple approach, the mounted assembly being preferably in a thermomechanically stable state, it is possible to take as the external temperature the initial internal temperature Tl of the fluid of the fluid cavity of the mounted assembly.

[0013] These two fluid transformations can take place at each time increment or one after the other over a period of time measurements. These evaluations of the intermediate volume variation must be made with measurements during the transient period of vehicle loading until the establishment of mechanical and possibly thermal equilibrium of the vehicle's mounted assemblies. Once these equilibria are established, the temperature and pressure variations of the fluid cavity are infinitesimal, they are then in a new thermomechanically stable state.

[0014] Once the intermediate volume variation has been evaluated for each equipped mounted assembly, the associated static load variation resulting from the coupling of the trailer to each equipped mounted assembly of the trailer must be evaluated. To do this, the intermediate volume variation of each equipped mounted assembly must be transformed into an equivalent load variation. To this end, a characteristic of the mounted assembly, in particular that of the tire, which is called the flattening rigidity per unit volume Kp, must be taken into account. This quantity makes it possible to relate the load carried by the mounted assembly to the volume variation of the fluid cavity generated by the load carried, the mounted assembly being crushed on a ground perpendicular to the applied load.This characteristic can of course be a fixed quantity or obtained by an experimental characterization of the assembled assembly or deduced from a numerical simulation campaign of the same assembled assembly. The assembled assembly must be in conditions of use close to those observed in the preliminary phase, that is to say around the internal temperature Tl and around the inflation pressure PL Generally, this flattening rigidity of the assembled assembly is a quantity defined locally around the initial point of use of the assembled assembly in the reference frame associated with the internal pressure P, the internal temperature T and the volume of the fluid cavity V.

[0015] Preferably, before the main step, the at least one equipped mounted assembly is in a thermomechanically stabilized state.

[0016] It is preferable that the transient phenomena recorded at the level of the sensors of the electronic device are due only to the disturbance of the balance of the trailer generated by the coupling of the latter to the towing vehicle. Thus, the other disturbances do not influence the response of the sensors, which improves the accuracy of the load variation. assessed by the method. However, if the disturbance of the trailer balance occurs on a different time scale than the disturbance associated with the trailer coupling or if this disturbance results in lower amplitudes of the responses of the sensors of the electronic device, the method remains entirely relevant.

[0017] Advantageously, the temperature sensor and / or the pressure sensor are placed in a sub-space of the closed fluid cavity delimited by the pneumatic casing and the wheel.

[0018] It is advantageous for sensors measuring low amplitude transient phenomena to be placed close to the occurrence of these transient phenomena so as not to be drowned in the measurement noise. Thus, in the presence for example of a centralized inflation pressure system for the mounted assemblies, it is advantageous for the sensors to be located at the level of the mounted assembly and not at the level of the centralized system. In the same logic, if the sensors are placed on the surface of the tire on the inside of the tire, the measurement will be more precise than if the sensors are mounted on the wheel rim due to the distance of the measurement taken from the occurrence of the physical phenomenon which acts on the deformation of the tire casing due to the transient nature of the physical phenomenon.Finally, preferably, the sensors, mainly due to the temperature sensor, are positioned far away from the wheel which has a higher thermal inertia than the tire.

[0019] Advantageously, the temperature sensor operates with a resolution of less than a hundredth of a degree.

[0020] Thus, it is possible to evaluate small volume variations and therefore small load variations.

[0021] Preferably, the acquisition frequency Fl is between 0.1 Hz and 10 Hz.

[0022] It is useful that the acquisition frequency Fl is high to capture the first transformation of the fluid which is rapid.

[0023] According to a particular embodiment, the determination of the initial volume V0 takes into account the geometry of a wheel rim and the geometry of an unloaded tire, mounted on a rim and inflated to a reference pressure PO, preferably the pressure PO is the initial pressure PI.

[0024] Advantageously, the geometry of the tire and / or the geometry of the rim is determined using an identifier of the tire and / or the wheel of the fitted assembly, preferably obtaining the identifier of said tire and / or said wheel is carried out by radiofrequency interrogation of an electronic device located on the fitted assembly.

[0025] To initiate the measurement system and in particular the determination of the initial volume VI of the fluid cavity, it is necessary to determine the volume V0 of the fluid cavity which corresponds to the volume delimited by the unloaded mounted assembly, i.e. the tire is mounted on the rim with a reference inflation pressure PO which is preferably the initial pressure PI.

[0026] To determine this volume V0, the axisymmetric geometry of the unloaded tire for a reference inflation pressure PO must be known. It is realistic to assume that the rim geometry is not influenced by the inflation pressure of the mounted assembly. These geometries can be accessed via a tire database. Knowing the identity of the tire and / or the wheel rim allows the correct geometries to be isolated in this database. The identity of the tire can be obtained through an optical reading of the regulatory markings affixed to the sidewall of the tire.The identity can also be transmitted by radio frequency interrogation of an electronic device present on the mounted assembly such as an RFID tag (acronym in English for Radio Frequency Identification), a TMS (acronym in English for "Tyre Mounted Sensor") mounted on the internal rubber of the tire or "inner liner" or a TPMS (acronym in English for "Tyre Pressure Monitoring System") mounted on the wheel rim for example.

[0027] Preferably, the Z load of each equipped mounted assembly is estimated by a Z = K PP * P * A(F) = Kp P * P * (Fl - F0) relation according to the following formula: [MATH1] , where Kpp is the flat-flat pneumatic stiffness of the assembled tire per unit volume.

[0028] It is a simple and elementary model which links the load applied to the tire to the variation in volume of the fluid cavity of the mounted assembly between a first state, for example unloaded, of volume V0 and a second state of volume VI, the inflation pressure P of the fluid cavity and the pneumatic rigidity of the mounted assembly corresponding to the flattening of the mounted assembly on a contact plane. Through this model, we make the assumption that the rigidity of a structural nature of the mounted assembly is negligible compared to that of a pneumatic, which is a realistic assumption for a trailer tire. However, it is quite possible to take into account the structural rigidity of the tire in the previous formula by adding it to the product of the pneumatic rigidity and the inflation pressure.

[0029] According to an advantageous embodiment, the variation in AV volume of each equipped mounted assembly is estimated by solving a differential equation according to the following form: [MATH 2] and With [MATH 3] , where P is the internal pressure, V is the internal volume and T is the internal temperature of the fluid cavity.

[0030] This differential equation translates the link between the parameters of the fluid in the cavity of the mounted assembly which are controlled on the one hand by an adiabatic transformation of the fluid and on the other hand by the fact that the fluid is a perfect gas.

[0031] The invention also relates to a method for estimating the load carried by a trailer integrally connected to a vehicle comprising the method for estimating the variation in the load carried by a mounted assembly of a trailer generated by the coupling of the trailer to a stationary vehicle, the method is characterized in that, in the preliminary phase, the method comprises a step of determining a first load distribution on each axle of the trailer, preferably on each mounted assembly of the trailer, associated with the application of an additional load exerted at the coupling point M of the trailer to the vehicle, optionally the method also comprises a step of determining a second load distribution on each axle of the trailer, preferably a second load distribution on each mounted assembly of the trailer, associated with the weight of the trailer, in that, in the main phase,the method comprises a step of estimating the load Z carried by each mounted assembly of each axle i of the trailer using the load variation AZ carried by the at least one equipped mounted assembly, the first load distribution associated with the application of an additional load to the coupling point M and the determination of the initial loads Zli of each mounted assembly of the trailer, optionally the step of estimating the load Z carried by each mounted assembly takes into account the second load distribution associated with the weight of the trailer, in that the method comprises a step of comparing to at least one threshold value S the load carried Z estimated at each axle i of the trailer and / or the total load carried of the trailer which is the summation of the loads carried by each axle i of the trailer, and when the at least one threshold value S is crossed, the mass content K of the trailer is adapted in the trailer during a secondary phase before carrying out again all the steps of the main phase.

[0032] By adding the load carried by the mounted assembly or axle before the trailer is hitched, this makes it possible to evaluate the total load established at the level of the mounted assembly or axle i of the trailer. The evaluation of the total load carried by the trailer then comes down to simply adding the static loads established on all the axles i of the trailer. It is then possible to verify that the loading conditions comply with the safety traffic regulations at the level of each mounted assembly, each axle of the trailer and of course the trailer even before the trailer starts to move.

[0033] By knowing the first load distribution at the level of the mounted assemblies or axles i of the trailer associated with an overload applied to the coupling point M of the trailer, it is possible to deduce from a single measurement on a mounted assembly equipped with the measuring device, the overloads on each mounted assembly or each axle of the trailer linked to the coupling of the trailer to the vehicle. By adding this overload linked to the coupling of the trailer to the static load linked to the mass of the trailer seen from each mounted assembly, it is possible to estimate the total load applied to each mounted assembly or each axle i of the trailer. Optionally, the static load linked to the mass of the trailer is obtained via the second load distribution on the mounted assemblies or axles i of the trailer associated with the mass of the trailer.

[0034] In the event that a safe driving condition is not obtained on the coupled trailer, whether at the level of a mounted assembly, an axle or the complete trailer. It is necessary to modify the arrangement of its contents, even if it means uncoupling the trailer from the vehicle, in order to shift the center of gravity of the trailer. This shift of the center of gravity of the trailer makes it possible to distribute differently the mass of the trailer taken up by each of the axles of the trailer or by the fifth wheel of the towing vehicle. Once the new arrangement has been made, it is necessary to repeat the process at the level of the main phase by coupling the trailer with its new arrangement and analyze the load carried by each mounted assembly equipped with the trailer. This new arrangement of the trailer may, for example, be a shift in the center of gravity of the trailer contents or a lightening of the trailer contents or a combination of both.

[0035] The invention also relates to a system for implementing the method for estimating the variation in load carried by a mounted assembly of a trailer securely connected to a vehicle generated by the coupling of the trailer to the stationary vehicle and / or for implementing the method for estimating the load carried by a trailer securely connected to a stationary vehicle comprising: • a trailer, equipped with a coupling device at a point M of the trailer capable of receiving a fifth wheel of a vehicle, each axle i of which comprises at least one mounted assembly equipped with an electronic device; • the electronic device comprising at least one temperature sensor, at least one electronic chip, at least one memory space capable of recording the signals from the sensor, and at least one first means of radiofrequency communication at least in transmission, preferably, the electronic device is fixed on the internal wall of the tire, very preferably at the level of the crown of the tire; • at least one means of calculation; and • at least one display means comprising at least one second radiofrequency communication means at least in reception

[0036] As mentioned by the method, the temperature sensor should be located on the mounted assembly which is rotated relative to the trailer. In order to move away from the elements of the mounted assembly with the highest thermal inertia, the electronic device is fixed to the inner wall of the tire at the level of the crown of the tire. Therefore, the electronic device conditioning at least the signals from the temperature sensor should be provided with a means of communication, for example radio frequency, in transmission to simply transmit the data beyond the mounted assembly where at least the display means will be located. Indeed, an alternative consists of integrating the calculation means, the one which calculates the variation in volume of the internal cavity of the mounted assembly at the level of the mounted assembly. This can be integrated into the electronic device or be in wired communication with the electronic device.So, the radio frequency communication medium of the electronic device is useful for transmitting. the results of calculations beyond the assembled assembly. Radiofrequency communication from the electronic device of the assembled assembly can be to the trailer, the vehicle or outside the two components to a device separate from these components such as a mobile phone, a tablet, a computer. These three elements can then represent the display means. However, the display means can also be a graphical interface of the trailer, the vehicle such as at the dashboard level for example.

[0037] Therefore, the proposed structural form allows it to adapt to several possible technical configurations while being functional for implementing the said process.

[0038] Preferably, the system comprises an analysis means capable of analyzing a result output from at least one calculation means.

[0039] The result of the calculation means is the load variation and / or the load carried by each mounted assembly equipped with the electronic device. If we want to compare this second quantity with a threshold S, an operation must be carried out before sending a message to the display means. This optional element of the system, which provides a service to the user of the convoy consisting of the towing vehicle and the trailer, must be positioned between the calculation means and the display means. Structurally, it can be associated with one and / or the other by a wired connection or be physically dissociated from these elements by means of radio frequency communication means.

[0040] According to a first particular embodiment, the at least one calculation means comprises at least one third radiofrequency transmission / reception communication means.

[0041] In the case where the calculation means is physically separated from the electronic device on the one hand and from the display means on the other hand, it is appropriate that the latter can communicate with the other two elements. This is the case, for example, when the calculation means is on the trailer and / or on the vehicle; it retrieves the temperature data from the electronic device through radio frequency communication with the latter. On the other hand, if the display means is on a mobile telephone, it transmits the calculation results to the display means via this radio frequency communication.

[0042] According to a second particular embodiment, the at least one analysis means comprises at least a fourth radiofrequency transmission / reception communication means.

[0043] In the case where the analysis means is physically separated from the calculation means and from the display means, it should be able to communicate with the other two elements. This is the case, for example, when the analysis means is on a server remote from the trailer; it retrieves the load variations or the loads applied to the various mounted assemblies of the trailer from the calculation means present on the trailer through radio frequency communication with the latter. On the other hand, if the display means is on a mobile phone, or any other electronic device equipped with a screen, it transmits the messages resulting from the comparison to the display means by radio frequency communication.

[0044] According to a third particular embodiment, the system comprises at least one reading means capable of at least reading data contained in the at least one memory space of the electronic device, comprising at least a fifth radiofrequency transmission / reception communication means.

[0045] In the case where the electronic device has a communication range that is not sufficient to ensure communication to the display means, it is appropriate to use a reading means to retrieve the data from the electronic device. This reading means ensures the function of capturing the measurement data. It then transfers them to the display means or any other element of the system requiring the data by radiofrequency communication for the rest of the process. This is a role of relaying the information by optimizing the communication coverage in relation to the electronic device present in the mounted assembly. Indeed, in order to reduce the mass of the electronic device at the tire level, it is appropriate to limit the energy source necessary for the transmission of data which is the energy-consuming function of the electronic device.

[0046] Preferably, part of the communication carried out by the communication means from and to the elements included in the group comprising the electronic device, the at least one calculation means, the at least one display means, the at least one analysis means and the at least one reading means is carried out by UHF radiofrequency waves, preferably in BLE (acronym in English for “Bluetooth Low Emission”).

[0047] The UHF band (acronym for Ultra High Frequencies) allows for significant data transmission with an interesting throughput, this is even more true in the high frequencies of the UHF band such as the BLE band (acronym in English for “Bluethooth Low Emission”). It is classically used in transport applications, which allows to share the system's communication resources with those already present on the trailer and / or the vehicle or in the road infrastructure.

[0048] Advantageously, the at least one display means is included in the group comprising a telephone, a computer, a human-machine interface located on the trailer and / or the vehicle, preferably located on the vehicle's instrument cluster.

[0049] The display means is used to warn the individual who is conducting operations on the convoy of the securing of the trailer of his convoy, whether he is the driver behind his driving position or another person responsible for the conformity of the convoy.

[0050] According to an advantageous embodiment, a part of the at least one reading means is located on the trailer.

[0051] According to another advantageous embodiment, part of the at least one calculation means and / or part of the at least one analysis means is located on the trailer, preferably located on the mounted assembly.

[0052] The trailer is a natural information relay instrument since the mounted assembly is connected to it and the safety condition is applied to it. Therefore, that the structural devices of the system are located on the trailer is entirely desirable although the alternative is also possible. However, the trailer allows to ensure a certain confidentiality of the data unlike communications to servers for example, unless secure communication protocols are implemented. Of course, in order to minimize the impact of this system in the trailer environment which is today complex and loaded, the localization of the functions at the level of the mounted assembly makes it possible to limit interference with the other structural components of the trailer and / or the vehicle. Brief description of the drawings

[0053] The invention will be better understood on reading the following description, given solely as a non-limiting example and with reference to the appended figures in which the same reference numbers designate identical parts throughout and in which: Fig. 1 presents a system for implementing the method for estimating the variation in load carried by a mounted assembly of a trailer securely connected to a towing vehicle and / or for implementing the method for estimating the load carrying a trailer securely connected to a vehicle according to the first embodiment of the invention; • Fig. 2 shows another system configuration according to the second embodiment of the invention; • Fig. 3 presents a block diagram of the method for estimating the variation in load carried and / or the load carried by a mounted assembly of a trailer securely connected to a vehicle according to the invention; • Fig. 4 shows a temporal evolution of the internal temperature of the fluidic cavity at the outlet of the temperature sensor • Fig. 5 shows a temporal evolution of the internal pressure of the fluid cavity at the outlet of the pressure sensor; • Fig. 6 presents a temporal estimate of the variation in volume of the fluidic cavity according to the invention; • Fig. 7 shows a time estimate of the load variation of a trailer mounted assembly associated with the trailer coupling to the vehicle. Detailed description of the embodiments

[0054] Fig. 1 illustrates an example of a system 2000 enabling the implementation of the method for estimating the variation in load carried and / or the method for estimating the load carried by a mounted assembly of a trailer integrally connected to a towing vehicle. This system 2000 comprises a trailer 2001 comprising three axles of mounted assemblies 2006 distributed over the trailer 2001. The trailer 2001 comprises a point M on the front part of the trailer which enables the attachment of a fifth wheel of a towing vehicle not shown in the figure. However, this towing vehicle exerts an external force AZ on the axle M on the trailer 2001. The trailer 2001 comprises a center of gravity G where the weight P of the trailer is applied which corresponds to the force generated by the total mass of the trailer taking into account the gravity of the Earth.This weight P is balanced by reaction forces exerted on the mounted assemblies 2006 of the trailer which are called Zi to Z3 depending on the axle where the mounted assembly 2006 is connected. The presence of an external force AZ on the point M of the vehicle, which corresponds to the attachment of the trailer coupling device 2001 to the vehicle, causes the appearance of additional reaction forces noted respectively AZi to AZ3 on the mounted assemblies 2006 of each respective axle which stabilize when the permanent regime is reached to balance the external force AZ. The additional forces of. reaction AZi to AZ3 take into account the reaction force exerted by the ground on the crutch device of the trailer 2001, the crutches are not shown here.

[0055] The objective of the method is to determine the reaction forces on each mounted assembly of the trailer which are stabilized when the steady state is reached.

[0056] At least one mounted assembly 2006 per axle of the vehicle 2001 is here equipped with an electronic device 2007. This electronic device 2007 is located in the fluid cavity of the mounted assembly 2006. Here, the electronic device 2007 is placed on the inner wall of the tire in line with the tread of the tire casing which ensures contact between the ground and the tire casing. It would have been possible to install the electronic device at the wheel rim of the mounted assembly, while remaining in the fluid cavity of the mounted assembly 2006. For example, the electronic device could have been integrated into the rim valve like certain TPMS systems (acronym in English for Tire Pressure Monitoring System).

[0057] This electronic device 2007 comprises a temperature sensor associated with a microcontroller and a radiofrequency device at least in transmission. The radiofrequency device therefore comprises a radio wave generator and a radiocommunication antenna for transmitting the generated radio waves. The radiofrequency device may also, optionally, comprise a radio wave receiver for receiving instructions from the outside in order, for example, to launch a measurement. This electronic device 2007 also comprises a memory space for storing the measurement data from the temperature sensor before transmitting them in the form of radio waves. The electronic device may transmit the raw measurement data or the data filtered by the microcontroller.Here, the electronic device 2007 emits radio waves in the UHF frequency band (acronym in English for Ultra High Frequency) and particularly in the BLE band (acronym in English for Bluetooth Low Emission).

[0058] Here, the exterior of the mounted assembly comprises at least the trailer 2001. This trailer 2001 firstly comprises a radio data reader 2005, operating in the UHF range, the antennas 2105 of which are located near the mounted assemblies 2006 during the rotation of these in order to recover the measurement data generated by the electronic device 2007. The data are then transferred, here by wire, to the calculation means 2002 located in the trailer 2001. A radio frequency transmission using specific means of communication would also have been possible. This calculation means 2002 comprises memory space and a processor to carry out its tasks: identify the quantities of the assembled assembly corresponding to the initial state, solve the differential equation which leads to the determination of the variation in volume of the fluidic cavity of each assembled assembly equipped with an electronic device 2007, and finally calculate the variation in load associated with the variation in volume having previously recovered the quantities of the tires necessary for this final task.

[0059] The results, and in particular the last data, are sent to an analysis means 2004. Here, the transmission of this data is done by wire, but radio frequency communication could have been set up. The analysis means 2004 makes comparisons between the results of the calculation means 2002 and threshold values ​​previously entered. These threshold values, such as the maximum authorized load per axle of the trailer or the maximum total load of the trailer or the maximum authorized load per mounted assembly, are possibly transmitted by hard-entering this data into the trailer 2001 or by querying a database remote from the trailer 2001. Of course, the analysis means 2004 can be integrated into the calculation means 2002.

[0060] Finally, the various output data from this analysis means 2004 are transmitted to display means 2003 via a fourth communication means 2104 which is embodied, among other things, by the radiocommunication antenna of the trailer 2001 and a second communication means 2102 present on the display means 2003.

[0061] These means of communication 2104 and 2102 transfer their data via a communication network to a tablet or smartphone 2003 in order to prevent compliance or non-compliance of the trailer load with respect to the threshold values ​​admissible by the trailer 2001 according to the legislation in force.

[0062] In the event of non-compliance with the trailer load, the trailer must be uncoupled from the vehicle in order to modify the load, whether it is a reduction in the mass of the load or a modification of the positioning of the load in the trailer in order to reduce the load on the axles of the trailer 2001 when the trailer is coupled to the towing vehicle. The main phase of the process for estimating the load carried by a mounted assembly of a trailer securely connected to a vehicle must then be repeated in order to check the compliance of the trailer loads with the legislation in force. If uncoupling the trailer is preferred to modify the trailer load, this operation remains optional.It is perfectly possible to continue recording the measuring signals from the electronic device 2007 while changing the trailer load and then wait for the overall balance. of the 2001 trailer to estimate the load carried by each 2006 mounted unit equipped with a 2007 electronic device of the 2001 trailer. Then to compare these new loads with the threshold values ​​previously used in order to verify the conformity of the 2001 trailer with the legislation in force.

[0063] Fig. 2 shows another configuration of the system 2000. This system 2000 comprises a trailer 2001 comprising three axles of mounted assemblies 2006 distributed on the trailer, the axles are numbered from 1 to 3 according to the direction of the trailer 2001 in forward motion. The trailer comprises a point M on the front part of the trailer which allows the attachment of the fifth wheel of a towing vehicle not shown in the figure. However, this towing vehicle exerts an external force AZ on the axle M on the trailer 2001.

[0064] At least one mounted assembly 2006 per axle of the trailer 2001 is equipped with an electronic device 2007. This electronic device 2007 is located in the fluid cavity of the mounted assembly 2006. Here, the electronic device 2007 is placed on the inner wall of the tire in line with the tread of the tire casing which ensures contact between the ground and the tire casing. It would have been possible to install the electronic device at the wheel rim of the mounted assembly, while remaining in the fluid cavity of the mounted assembly 2006. For example, the electronic device could have been integrated into the rim valve like certain TPMS systems (Tire Pressure Monitoring Systems).

[0065] This electronic device 2007 comprises a temperature sensor associated with a microcontroller and a radiofrequency device at least in transmission. The radiofrequency device therefore comprises a radio wave generator and a radiocommunication antenna for transmitting the generated radio waves. The radiofrequency device may also, optionally, comprise a radio wave receiver for receiving external instructors in order, for example, to initiate a measurement. This electronic device 2007 also comprises a memory space for storing the measurement data from the temperature sensor before transmitting them in the form of radio waves. The electronic device may transmit the raw measurement data or the data filtered by the microcontroller.Here, the electronic device 2007 emits radio waves in the UHF frequency band (acronym in English for Ultra High Frequency) and particularly in the BLE band (acronym in English for Bluetooth Low Emission).

[0066] Here, the exterior of the assembled assembly includes at least the towing vehicle and the trailer 2001. This trailer 2001 firstly includes a data reader radioelectric devices 2005, operating in the UHF range, whose receiving antennas 2105 are located near the mounted assemblies 2006 during the rotation of these, in order to recover the measurement data generated by the electronic device 2007. The data are then transferred after processing, here by wire, to the transmitting antenna of the means of communication 2104 located in the trailer 2001. A radiofrequency transmission using specific means of communication would also have been possible.This calculation means 2002 includes memory space and a processor to carry out its tasks: identify the quantities of the assembled assembly corresponding to the initial state, solve the differential equation which leads to the determination of the variation in volume of the fluidic cavity of each assembled assembly equipped with an electronic device 2007, and finally calculate the variation in load associated with the variation in volume having previously recovered the quantities of the tires necessary for this final task.

[0067] The data is then transferred, here by wire, to the computing means 2002 located in the trailer 2001. However, the data could have been transmitted to physical means remote from the trailer 2001.

[0068] The first means is a calculation means 2002 comprising transmission / reception communication means. These communication means in a configuration other than that of Figure 2 could receive the radio waves emitted by the transmission communication means 2105 to transform them into digital data usable by the calculation means 2002. The calculation means 2002 comprises memory space and a processor to carry out these tasks: identify the quantities of the mounted assembly corresponding to the initial state, solve the differential equation which leads to the determination of the variation in volume of the fluidic cavity of each mounted assembly equipped with an electronic device 2007, and finally calculate the variation in load associated with the variation in volume having previously recovered the quantities of the tires necessary for this final task.

[0069] The results and in particular the last data are sent to a second means which corresponds to an analysis means 2004. Here, the transmission of this data is done by means of a wired communication. The analysis means 2004 makes comparisons between the results of the calculation means 2002 which they recover, this communication could be a radiofrequency transmission from the calculation means 2002 using reception communication means 2104, and threshold values ​​previously entered. These threshold values ​​such as the maximum authorized load per axle of the vehicle or the maximum total load of the vehicle or the maximum load authorized per mounted assembly are possibly transmitted by querying a remote database containing data on the trailer 2001. Of course, here, the analysis means 2004 is integrated into the calculation means 2002.

[0070] Finally, the various output data from this analysis means 2004 are transmitted to display means 2003 via a fourth communication means 2104 in transmission and a second communication means 2102 present on the display means 2003. Here, the display means consist of a digital tablet 2003 possibly remote from the trailer 2001 and possibly a man-machine interface within the trailer 2001 comprising a display screen. These display means could also be a screen on the dashboard of the towing vehicle with radiofrequency transmission of the data to be displayed.

[0071] The 2003 display means aim to warn of the conformity or non-conformity of the trailer loading in relation to the admissible threshold values ​​according to the legislation in force.

[0072] Of course, these two embodiments of the system for implementing the method for estimating the variation in load carried and / or the load carried by a mounted assembly of a vehicle integrally connected to a trailer are only illustrative examples of the system which are not limited to these two configurations. A first extreme configuration consists of integrating all of the calculation and analysis means within the electronic device on board the mounted assembly which transmits the results to a display means remote from the trailer. The other extreme configuration consists of transferring by radio waves the measurement data recorded at the electronic device and carrying out the other steps of the method on means remote from the vehicle, without ever passing through the trailer or the towing vehicle.

[0073] Fig. 3 shows a block diagram of the method for estimating the variation in load carried and / or the method for estimating the load carried by a mounted assembly of a trailer securely connected to a stationary towing vehicle. This method comprises several phases.

[0074] The first is a preliminary phase which includes at least actions 1 to 6 which follow one another through a continuous line link system. This preliminary phase which focuses on the unhitched trailer obviously includes the equipment of the trailer, including its loading, ideally at the level of the mounted assemblies, by the installation of a temperature sensor capable of measuring the internal temperature of the fluidic cavity delimited by the internal surface of the tire and the wheel rim via a dedicated electronic device. The first steps, noted 1 and 2, consist of determining the physical quantities of the fluid cavity of the mounted assemblies equipped with the measuring device such as the inflation pressure PI and the internal temperature Tl. Preferably, these determinations can be made as a lump sum or through a specific measurement. Step noted 3 consists of determining the load carried ZI by the mounted assembly equipped with the measuring device of the unhitched vehicle. This determination can be made as a lump sum by making assumptions of distribution of the total load of the trailer between the various axles of the latter. The total load of the trailer being a given, for example from the trailer manufacturer, corresponds for example to the unladen mass of the trailer as specified by the technical instructions of the trailer manufacturer.Of course, it is also possible to integrate the loading of the trailer. The step referenced 4 corresponds to obtaining specific quantities of the assembled assembly equipped with a measuring device. One of these quantities is the volume VO corresponds to the volume occupied by the fluid cavity of the assembled assembly when the assembled assembly is inflated to the pressure PI, strictly speaking, under the internal temperature Tl, but in the absence of any load carried, that is to say not resting on the ground. The second quantity is the flattening rigidity of the pneumatic envelope of the assembled assembly per unit of volume Kp, possibly depending on the inflation pressure PI, the internal temperature Tl and the load carried ZI. Finally, a third set of quantities are those associated with the ideal gas behavior laws for the nature of the gas contained in the fluid cavity of the assembled assembly.And the penultimate step of the preliminary phase, referenced 5, is a step of determining the volume occupied VI by the fluidic cavity of the instrumented mounted assembly subjected to the load ZI and under the inflation pressure PI and the temperature TL Finally the last step, noted 6, of the preliminary phase is the evaluation of the quantity of gas contained in the fluidic cavity of the instrumented mounted assembly by determining the number of moles of gas n present within the volume VL Here, the hypotheses associated with the ideal gas condition apply well, it is still necessary to identify the nature of the composition of the gas, that is to say a monatomic gas or a gas mixture.Furthermore, it is important in this preliminary phase, although not shown, to determine the evolution law linking the variation of internal pressure P to the variation of internal temperature T for the fluid of the fluidic cavity of the mounted assembly considered during an adiabatic transformation around the operating point of the mounted assembly, i.e. the pressure PI, the temperature Tl and the load ZI. Finally, in the preliminary phase, it is necessary, although not shown, to determine the load distribution on each axle of the trailer, preferably on each assembly. mounted on the trailer, associated with a load applied to the coupling point M of the trailer. Optionally, a second load distribution on each axle of the trailer, preferably on each mounted assembly of the trailer, the trailer being uncoupled, can be considered. This second load distribution is linked to the total mass of the uncoupled trailer.

[0075] Then we move on to the main step, the beginning of which corresponds to the coupling of said trailer to the towing vehicle. Necessarily, we record the temporal variation of the internal temperature T(t) of each instrumented mounted assembly of the trailer, which are of the order of a hundredth of a degree for, for example, passenger vehicles and trailers adapted to this type of vehicle. These recordings are then stored in a memory space to first filter the raw data using a low-pass filter to eliminate high-frequency phenomena, which corresponds to step referenced 11. Then we determine the temporal variation of internal pressure P(t) of the fluid cavity using the temporal variation of internal temperature T(t) by using the evolution law determined in the preliminary step, which corresponds to step 12.Optionally, the second internal temperature variation corresponding to the second transformation of the fluid corresponding to thermal equilibrium with the external environment is extracted from the recording of the temporal variation of the internal temperature T(t) of each instrumented mounted assembly of the vehicle. In parallel, for this option, the internal pressure variation of the fluid in the fluid cavity of the equipped mounted assembly is recorded, having previously equipped the mounted assembly with a pressure sensor.This recording must at least include the internal pressure variations corresponding to the time frame after the first transformation of the fluid. In this option, the recorded internal temperature variation T(t) and internal pressure P(t) are used to evaluate the second transformation of the fluid in the fluid cavity corresponding to the establishment of thermal equilibrium between the fluid cavity and the external environment, which is made necessary by the first transformation of the fluid associated with the coupling of the trailer. The connection system between optional steps and the essential steps in the process are illustrated with gray lines instead of black. However, the connection systems of the main phase are illustrated by dotted lines, while those of the preliminary phase are solid lines. Finally, as will be seen later, the secondary phase has a connection system in the form of dashed lines.

[0076] One of the important steps of the main phase is the determination of the AV volume variation of the fluidic cavity of each instrumented assembly through step 13. This corresponds to taking into account at least the adiabatic transformation of the fluid in the fluid cavity due to the instantaneous attachment of the trailer to the towing vehicle which modifies the thermomechanical equilibrium of all the mounted assemblies of the trailer and consequently of the fluid trapped in each fluid cavity of the mounted assemblies. In addition, the fluid is assumed to follow the behavior of an ideal gas. From the internal temperature variation T(t) of each instrumented mounted assembly, it is possible to determine the internal pressure variation P(t) via the evolution law identified in the preliminary phase for an adiabatic transformation of the fluid.

[0077] Using the variation of the internal pressure and the internal temperature, it is possible to feed a differential equation taking into account the previous hypotheses. The resolution by time increment of the differential equation makes it possible to obtain an estimate of the associated time variation of the volume of the fluidic cavity AV(t) corresponding to step 13. Optionally, the method can be completed by the second variation of the internal temperature T of the fluidic cavity and the measurement of the internal pressure variation P(t) in order to evaluate a second variation of volume of the fluidic cavity associated with the transformation of the fluid due to the heat exchange which takes place between the fluidic cavity of the mounted assembly and the external environment through the components of the mounted assembly; that is to say the pneumatic casing and the wheel.This second transformation is generally subsequent to the adiabatic transformation since it is the temperature variation generated by the adiabatic transformation which is at the origin of the thermal imbalance between the fluidic cavity and the external environment.

[0078] Another important step in the main phase is the evaluation of the load variation AZ associated with the single volume variation previously evaluated AV which corresponds to step 14. For this, it is necessary to take into account again the flattening rigidity of the assembled assembly Kp per unit of volume. This rigidity can include a pneumatic component and a structural component. Taking into account a single pneumatic component Kpp can be sufficient for a reliable estimation of the load variation AZ.

[0079] From this variation in load carried AZ, the initial load carried ZI must be added to obtain the load carried by the instrumented mounted assembly in step 15. From this quantity on the scale of the mounted assembly, it is easy to go back to the load carried by each axle i of the trailer and therefore to the total load carried by the trailer. To do this, on the assumption that only one or a few mounted assemblies, but not all of the trailer are equipped with a measuring device, the method comprises in the preliminary phase an estimation of the load distribution on each mounted assembly or each axle of the trailer associated with an overload applied to the coupling point M of the trailer. Optionally, a second load distribution can be used to estimate the initial load of each mounted assembly or each axle of the trailer associated with the total mass of the trailer alone.

[0080] The last step, noted 16, is the comparison of the load carried Z with respect to a threshold S at the level of each mounted assembly, but also in the same way for each axle i of the trailer and finally at the level of the complete trailer. Generally, these thresholds S can be the safety conditions specific to each national legislation for the circulation of a convoy consisting of a tractor vehicle and a trailer.

[0081] According to the result of this comparison, the convoy is ready to take the road with the trailer coupled to the towing vehicle since all the safety conditions are respected according to step 17 of the main phase. Otherwise, a secondary phase is followed, comprising at least step 20, in which the loading of the coupled trailer is adapted. This adaptation of the loading can take place while the trailer remains coupled. It may also be considered to uncouple the trailer from the vehicle during this adaptation of the trailer loading. Adapting the loading consists of a modification of the location of the load in the trailer and / or a modification of the contents of the load in order, for example, to reduce the mass of the load.Once step 20 is completed, the main step should be repeated, if necessary reattaching the trailer to the vehicle and recording the temperature of the fluid cavity of each instrumented mounted assembly of the trailer, which corresponds respectively to step 11 of the synoptic, optionally the internal pressure is also measured, corresponding to step 12, in particular for the second transformation of the fluid associated with thermal equilibrium. This secondary phase is repeated until the criteria authorizing the completion of step 17 are met.

[0082] Fig. 4 shows the time evolution of the temperature delivered by the temperature sensor of the electronic device placed on a mounted assembly of the trailer. The curve consisting of points 10 is the raw measurement of the temperature sensor while curve 11 corresponds to the time evolution of the filtered internal temperature, which is cleaned of high-frequency noise. It is this second curve which will then be used in the synoptic of figure 3.

[0083] This time recording of the internal temperature of the fluid cavity of the mounted assembly begins in the preliminary phase before the trailer is coupled to the vehicle. tractor. The moment of hitching the trailer corresponds to the abscissa of point 100 which marks the beginning of the main phase. From this point 100, we observe a rapid drop in the internal temperature of the fluid cavity up to point 101 where the drop in temperature stops and even increases to a lesser extent. This point 101 marks the transition between the work of the fluid associated with hitching the trailer which corresponds to a first transformation of the fluid which is similar to an adiabatic transformation and the heat exchange towards the outside which corresponds to a second transformation of the fluid. The abscissa of this point 101 corresponds to the duration T0 taking as the origin of the times the abscissa of point 100. Thus, the preliminary phase 50 ends at the abscissa of point 100. It precedes the main phase which is separated into two successive phases.The first phase 51 is similar to an adiabatic transformation of the fluid corresponding to the work of the fluid following the coupling of the trailer. The second phase 52 corresponds to a thermal exchange of the fluid with the exterior.

[0084] Fig. 5 shows the time evolution of the internal pressure of the fluid cavity. Here, this time evolution is delivered entirely by a pressure sensor of the electronic device arranged on a mounted assembly of the trailer as illustrated by curve 12.

[0085] This evolution of the internal pressure 12 of the fluid cavity of the mounted assembly begins in the preliminary phase before the trailer is coupled to the towing vehicle. The moment of coupling of the trailer corresponds to the abscissa of point 100 which marks the beginning of the main phase. From this point 100, a rapid drop in the internal pressure of the fluid cavity is then observed up to point 101 where the drop in pressure stops and then increases to a certain extent. This point 101 marks the transition between the work of the fluid associated with the coupling of the trailer which corresponds to a first transformation of the fluid which is similar to an adiabatic transformation and then the heat exchange towards the outside which corresponds to a second transformation of the fluid. The abscissa of this point 101 corresponds to the duration T0 taking as the origin of the times the abscissa of point 100. Thus, the preliminary phase 50 ends at the abscissa of point 100.It precedes the main phase which is separated into two successive phases. The first phase 51 is similar to an adiabatic transformation of the fluid corresponding to the work of the fluid following the coupling of the trailer. The second phase 52 corresponds to a thermal exchange of the fluid with the exterior.

[0086] Fig. 6 shows the time evolution of the internal volume of the fluid cavity. Here, this time evolution, represented by the curve, is the output of the calculation of the variation of volume by the proposed differential equation also taking into account thermal equilibrium with the external environment.

[0087] This evolution of the internal volume of the fluid cavity of the mounted assembly begins in the preliminary phase before the trailer is coupled to the towing vehicle. The moment of coupling of the trailer corresponds to the abscissa of point 100 which marks the beginning of the main phase. From this point 100, we then observe a rapid increase in the internal volume of the fluid cavity up to point 101 where the increase in the internal volume stops and then decreases to a certain extent. This point 101 marks the transition between the work of the fluid associated with the coupling of the trailer which corresponds to a first transformation of the fluid which is similar to an adiabatic transformation and the heat exchange towards the outside which corresponds to a second transformation of the fluid. The abscissa of this point 101 corresponds to the duration T0 taking as the origin of the times the abscissa of point 100. Thus, the preliminary phase 50 ends at the abscissa of point 100.It precedes the main phase which is separated into two successive phases. The first phase 51 is similar to an adiabatic transformation of the fluid corresponding to the work of the fluid following the coupling of the trailer. The second phase 52 corresponds to a thermal exchange of the fluid with the exterior.

[0088] It is noted that at the end of phase 51, a good estimate of the volume variation of the mounted assembly is obtained, which clearly shows that the work generated by the load variation subjected to the mounted assembly occurs mainly during phase 51. The variations or oscillations observed correspond to the fluctuations of the transient phase corresponding to thermal equilibrium. Therefore, the method described here produces a continuous measurement of the internal volume variation of the mounted assembly in the time domain.

[0089] Fig. 7 shows the time evolution of the load variation applied to a mounted assembly equipped with the electronic device. Here, this time evolution, represented by curve 14, is the output of the calculation of the volume variation by the proposed differential equation taking into account the thermal equilibrium with the external environment which is multiplied by the flattening rigidity of the mounted assembly. Here, the rigidity taken is that which is locally identified at the level of the initial pressure of the mounted assembly, of the initial load applied to the mounted assembly and corresponding to the initial temperature. We could have taken into account the global rigidity defined by the proposed formula which would already have given a good order of magnitude.

[0090] This evolution of the load 14 of the fluid cavity of the mounted assembly begins in the preliminary phase before the trailer is coupled to the towing vehicle. The moment of coupling of the trailer corresponds to the abscissa of point 100 which marks the beginning of the main phase. From this point 100, a rapid decrease in the applied load is then observed up to point 101 where the drop in load stops and then decreases to a certain extent. This point 101 marks the transition between the work of the fluid associated with the coupling of the trailer which corresponds to a first transformation of the fluid which is similar to an adiabatic transformation and the heat exchange towards the outside which corresponds to a second transformation of the fluid. The abscissa of this point 101 corresponds to the duration T0 taking as the origin of the times the abscissa of point 100. Thus, the preliminary phase 50 ends at the abscissa of point 100.It precedes the main phase which is separated into two successive phases. The first phase 51 is similar to an adiabatic transformation of the fluid corresponding to the work of the fluid following the coupling of the trailer. The second phase 52 corresponds to a thermal exchange of the fluid with the exterior.

[0091] It is noted that at the end of phase 51, a good estimate of the load variation applied to the mounted assembly is obtained, which clearly shows that the work generated by the load variation occurs mainly during phase 51. The variations or oscillations observed correspond to the fluctuations of the transient phase corresponding to the thermal equilibrium. Therefore, the method described here produces a continuous measurement of the temporal load variation of the mounted assembly in the time domain. Curve 80 corresponds to the measurement on a ground scale of the overload applied to the mounted assembly of the trailer, which guarantees a reasonable estimate of the overload applied to the equipped mounted assembly. In conclusion, the applied load variation is well captured by the proposed method.

Claims

CLAIMS 1. Method for estimating the variation in load carried by a trailer assembly generated by coupling the trailer to the stationary towing vehicle comprising the following steps: In the preliminary phase, - Equip at least one mounted assembly of at least one axle of the trailer not coupled to the towing vehicle with at least one temperature sensor, said sensor being capable of measuring the internal temperature of the fluid cavity of the mounted assembly delimited by a pneumatic casing and a wheel, preferably at least one mounted assembly of each axle of the trailer, very preferably all the mounted assemblies of all the axles of the trailer; - Determine the initial load ZI applied to at least one mounted unit equipped with the uncoupled trailer, - Determine the initial inflation pressure PI of the fluid cavity of at least one mounted assembly equipped with the trailer; - Determine the initial internal temperature Tl of the fluid cavity of at least one mounted assembly equipped with the trailer; - Evaluate the initial volume VI of at least one equipped mounted assembly using a first function comprising as parameter the volume VO of the fluid cavity of the unloaded mounted assembly inflated to the initial pressure PI and the flattening rigidity of the tire of the mounted assembly per unit of volume Kp, - Evaluate the number of moles of fluid n in the fluid cavity of each assembled assembly equipped from a model taking into account the inflation pressure PI, the initial volume VI, the temperature Tl; - Determine a law of evolution of the internal pressure P of the fluidic cavity from the internal temperature T during an adiabatic transformation for the at least one assembled assembly, inflated and subjected to the load Zl, equipped with at least one temperature sensor; In the main phase: - Attach the trailer to the vehicle at a point geometry M of the trailer - Record the internal temperature T of the fluidic cavity of at least one mounted assembly equipped at an acquisition frequency Fl; - Determine the internal pressure P of the fluid cavity of at least one equipped mounted assembly using the evolution law determined in the preliminary phase; - Evaluate an intermediate volume variation AV of at least one equipped mounted assembly using the recorded internal temperature T and the internal pressure P determined using a fluid model in adiabatic transformation, the fluid having perfect gas behavior; and - Estimate a load variation AZ carried by the at least one mounted assembly equipped using a second function comprising as parameter the intermediate AV volume variation evaluated and the flattening rigidity of the tire of the mounted assembly per unit of volume Kp.

2. Method for estimating the variation in the load carried by a mounted assembly of a trailer generated by the coupling of the trailer to a stationary towing vehicle according to claim 1 in which, in the preliminary phase, the at least one mounted assembly equipped with the at least one axle of the trailer comprising a pressure sensor capable of measuring the internal pressure of the fluid cavity, the method comprises, in the main phase, a step for recording the internal pressure P of the fluid cavity of the at least one mounted assembly equipped when, at least the recorded internal temperature T changes direction of variation or after a duration T0 corresponding to the end of the adiabatic transformation of the fluid and the method comprises a second step of evaluating the intermediate volume variation AV2 of the at least one mounted assembly equipped taking into account the recorded internal pressure P,the recorded internal temperature T corresponds to the recording period of the internal pressure P using a fluid model in adiabatic transformation, the fluid having an ideal gas behavior., 3. Method for estimating the variation in the load carried by a mounted assembly of a trailer generated by the coupling of the trailer to a stationary towing vehicle according to one of claims 1 to 2 in which, before the main step, the at least one equipped mounted assembly is in a thermomechanically stabilized state.

4. Method for estimating the variation in the load carried by a mounted assembly of a trailer generated by the coupling of the trailer to a stationary towing vehicle according to one of claims 1 to 3 in which the temperature sensor and / or the pressure sensor are placed in a subspace of the closed fluid cavity delimited by the pneumatic envelope and the wheel.

5. Method for estimating the variation in the load carried by a mounted assembly of a trailer generated by the coupling of the trailer to a stationary towing vehicle according to one of claims 1 to 4 in which the acquisition frequency Fl is between 0.1 Hz and 10 Hz.

6. Method for estimating the variation in the load carried by a mounted assembly of a trailer generated by the coupling of the trailer to a stationary towing vehicle according to one of claims 1 to 5 in which the determination of the initial volume V0 takes into account the geometry of a wheel rim and the geometry of an unloaded tire, mounted on a rim and inflated to a reference pressure PO, preferably the pressure PO is the initial pressure PI.

7. Method for estimating the variation in the load carried by a mounted assembly of a trailer generated by the coupling of the trailer to a stationary towing vehicle according to claim 6 in which the geometry of the tire and / or the geometry of the rim is determined using an identifier of the tire and / or the wheel of the equipped mounted assembly, preferably obtaining the identifier of said tire and / or said wheel is carried out by a radiofrequency interrogation of an electronic device located on the mounted assembly.

8. Method for estimating the variation in the load carried by a mounted assembly of a trailer generated by the coupling of the trailer to a stationary towing vehicle according to one of claims 1 to 7 in which the load Z of each equipped mounted assembly is estimated by a relationship according to the following formula: Z = K PP * P * A(F) = K PP * P * (Fl FO) [MATH1] where Kpp is the flattening pneumatic stiffness of the assembled tire per unit volume.

9. Method for estimating the variation in the load carried by a mounted assembly of a trailer generated by the coupling of the trailer to a stationary towing vehicle according to one of claims 1 to 8 in which the variation in AV volume of each mounted assembly equipped is estimated by solving the following differential equation: [MATH 2] , where P is the internal pressure, V is the internal volume and T is the internal temperature of the fluid cavity.

10. Method for estimating the load carried by a trailer integrally connected to a vehicle comprising the method for estimating the variation in the load carried by a mounted assembly of a trailer generated by the coupling of the trailer to a stationary vehicle according to one of claims 1 to 9, the method is characterized in that, in the preliminary phase, the method comprises a step of determining a first load distribution on each axle of the trailer, preferably on each mounted assembly of the trailer, associated with the application of an additional load exerted at the coupling point M of the trailer to the vehicle, optionally the method also comprises a step of determining a second load distribution on each axle of the trailer, preferably a second load distribution on each mounted assembly of the trailer, associated with the weight of the trailer, in that, in the main phase,the method comprises a step of estimating the load Z carried by each mounted assembly of each axle i of the trailer using the load variation AZ carried by the at least one equipped mounted assembly, the first load distribution associated with the application of an additional load to the coupling point M and the determination of the initial loads Zli of each mounted assembly of the trailer, optionally the step of estimating the load Z carried by each mounted assembly takes into account the second load distribution associated with the weight of the trailer, in that the method comprises a step of comparing to at least one threshold value S the load carried Z estimated at each axle i of the trailer and / or the total load carried by the trailer which is the summation of the loads carried by each axle i of the trailer, and when the at least one threshold value S is crossed,the mass content K of the trailer is adapted in the trailer during a secondary phase before carrying out all the steps of the main phase again., 11. System (2000) for implementing the method for estimating the variation in load carried by a mounted assembly of a trailer securely connected to a vehicle generated by the coupling of the trailer to the stationary vehicle according to one of claims 1 to 9 and / or for implementing the method for estimating the load carried by a trailer securely connected to a stationary vehicle according to claim 10 comprising: - A trailer (2001), provided with a coupling device at a point M of the trailer capable of receiving a fifth wheel of a vehicle, each axle i of which comprises at least one mounted assembly (2006) equipped with an electronic device (2007); the electronic device (2007) comprising at least one temperature sensor, at least one electronic chip, at least one memory space capable of recording the signals from the sensor, and at least one first radiofrequency communication means (2101) at least in transmission; at least one calculation means (2002); and at least one display means (2003) comprising at least one second radiofrequency communication means (2102) at least in reception 12. System (2000) for implementing the method for estimating the variation in load carried by a mounted assembly of a trailer securely connected to a stationary vehicle and / or for implementing the method for estimating the load carried by a trailer securely connected to a stationary vehicle according to claim 11 in which the system (2000) comprises an analysis means (2004) capable of analyzing a result output from the at least one calculation means (2002).

13. System (2000) for implementing the method for estimating the variation in load carried by a mounted assembly of a trailer securely connected to a stationary vehicle and / or for implementing the method for estimating the load carried by a trailer securely connected to a stationary vehicle according to one of claims 11 to 12 in which the at least one calculation means (2002) comprises at least one third radiofrequency transmission / reception communication means (2103).

14. System (2000) for implementing the method for estimating the variation in load carried by a mounted assembly of a trailer securely connected to a stationary vehicle and / or for implementing the method for estimating the load carried by a trailer securely connected to a stationary vehicle according to claim 13 in which the at least one analysis means (2004) comprising at least a fourth radiofrequency transmission / reception communication means (2104) 15. System (2000) implementing the method for estimating the variation in load carried by a mounted assembly of a trailer securely connected to a stationary vehicle and / or for implementing the method for estimating the load carried by a trailer securely connected to a stationary vehicle according to one of claims 11 to 14 in which the system (2000) comprises at least one reading means (2005) capable of at least reading data contained in the at least one memory space of the electronic device (2007) comprising at least one fifth communication means (2105) at least in reception.

16. System (2000) implementing the method for estimating the variation in load carried by a mounted assembly of a trailer securely connected to a stationary vehicle and / or for implementing the method for estimating the load carried by a trailer securely connected to a stationary vehicle according to one of claims 11 to 15 wherein part of the communication carried out by the communication means (2101, 2102, 2103, 2104, 2105) from and to the elements included in the group comprising the electronic device (2007), the at least one calculation means (2002), the at least one display means (2003), the at least one analysis means (2004) and the at least one reading means (2005) is carried out by UHF radiofrequency waves, preferably in BLE.

17. System (2000) for implementing the method for estimating the variation in load carried by a mounted assembly of a trailer securely connected to a stationary vehicle and / or for implementing the method for estimating the load carried by a trailer securely connected to a stationary vehicle according to one of claims 11 to 16 in which the at least one display means (2003) is included in the group comprising, a telephone, a computer, a human-machine interface located on the trailer (2001) and / or the vehicle, preferably located on the instrument cluster of the vehicle 18. System (2000) for implementing the method for estimating the variation in load carried by a mounted assembly of a trailer securely connected to a stationary vehicle and / or for implementing the method for estimating the load carried by a trailer securely connected to a stationary vehicle according to one of claims 11 to 17 in which a part of the at least one reading means (2005) is located on the trailer (2001).

19. System (2000) implementing the method for estimating the variation in load carried by a mounted assembly of a trailer securely connected to a stationary vehicle and / or for implementing the method for estimating the load carried by a trailer securely connected to a stationary vehicle according to one of claims 11 to 18 in which a part of the at least one calculation means (2002) and / or a part of the at least one analysis means (2004) is located on the trailer (2001), preferably located on the mounted assembly (2006).

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