Method for detecting a change in position of at least one wheel of a motor vehicle

Abstract

The present invention relates to a method for detecting a change in position of at least one wheel (16a, 16b, 16c, 16d) of a motor vehicle (10), said vehicle comprising at least one central processing unit (12), at least one wheel unit (14a, 14b, 14c, 14d) and at least one two-way communication component (18), said wheel unit comprising an electronic assembly of sensors and being mounted on said wheel (16a, 16b, 16c, 16d), characterized in that the method especially comprises a first comparison step during which a first evaluation pattern is compared with a first reference pattern in order to determine whether the position of the wheel (16a, 16b, 16c, 16d) has changed, said patterns characterizing the actual position of the wheel unit in the motor vehicle (10).

Description

Technical Field

[0001] The present patent application relates to a method for detecting a change in position of at least one wheel of a motor vehicle, which method is particularly applied in the field of motor vehicle equipment. Background Art

[0002] For safety purposes, it is known to equip motor vehicles with a monitoring system known by the acronym "TPMS" (Tire Pressure Monitoring System).

[0003] Such a monitoring system generally has: a central processing unit; wheel units, each wheel unit being equipped with an associated wheel of the vehicle; and a radio frequency communication component, which radio frequency communication component is adapted to ensure communication between each wheel unit and the central processing unit.

[0004] The central unit has an electronic processor abbreviated as "ECU" (Electronic Control Unit).

[0005] Each wheel unit includes an electronic assembly of sensors for detecting, in particular, anomalies of the wheel. For example, these sensors can be tire inflation pressure sensors, temperature sensors, and wheel acceleration sensors.

[0006] In addition, each wheel unit has a battery and a memory.

[0007] The communication component can exchange messages or signals bidirectionally between the central unit and / or a mobile terminal and each wheel unit. These messages particularly include data characterizing the operating parameters of each wheel and the identification code of each wheel unit.

[0008] The communication is carried out according to a communication protocol for short-range bidirectional data exchange using ultra-high frequency or "UHF" radio waves, for example according to a type of communication protocol.

[0009] To utilize the data transmitted by the wheel units, it is essential to know the position of each wheel unit on the various wheels of the vehicle. More specifically, position information is necessary in order to know what recommended pressure thresholds must be applied (depending on the question of whether it is a front wheel or a rear wheel), and also in order to display the current pressure value at the associated wheel.

[0010] The position of the wheel units relative to the position of the wheels in the vehicle is generally verified at the start of a new driving cycle, and according to the prior art, it is necessary to regularly send messages synchronized with a determined angular position from the wheel units to the central unit.

[0011] To this end, in particular, document WO 2012 / 139711 is known, which describes a method for determining the position of the wheels of a motor vehicle by synchronous messages.

[0012] The energy required to send messages from each wheel unit is provided by a battery associated with the sending wheel unit.

[0013] However, the battery of each wheel unit has a limited service life and is not intended to be recharged. Therefore, energy consumption must be limited to optimize the service life of the battery of each wheel unit.

[0014] In addition, it should be noted that when verifying the position of the wheel unit at the start of each driving cycle, most of the time, this results in an unchanged result of the wheel unit position. This is because the wheels are only replaced or swapped once or twice a year on average, especially when swapping between winter and summer tires, which represents a proportion of less than one percent of the effective changes in the wheel unit position of the wheel unit positioning program.

[0015] Also known is the method for verifying a change in the position of a wheel unit described in document US 2011 / 0304451, which interrogates each wheel unit when the engine is started to determine whether the position of the wheel unit has changed since the last engine start.

[0016] Although this method makes it possible to limit the procedure for verifying the position of the wheel unit, this method is complex to implement and requires an auxiliary component assembly for each wheel unit, such as a dedicated low-frequency antenna, a low-frequency controller, and dedicated lines.

[0017] The prior art does not provide a simple and reliable solution to ensure the detection of changes in the position of the wheel unit with low energy consumption. Summary of the Invention

[0018] The present invention aims to solve these drawbacks.

[0019] This object and other objects that will become apparent by reading the following description are achieved by a method for detecting a change in the position of at least one wheel of a motor vehicle, said vehicle having:

[0020] - at least one central processing unit,

[0021] - at least one wheel unit, said wheel unit including an electronic assembly of sensors and said wheel unit being mounted on said wheel of the motor vehicle, and

[0022] - at least one two-way radio frequency communication component, which is designed to ensure communication between the wheel unit and the central unit,

[0023] The method at least includes:

[0024] - A first preliminary configuration step, during which the central unit sends a series of messages to the wheel unit via the communication component. This series of messages is sent according to the pre-determined instantaneous angular position of the associated wheel while the vehicle is in motion, and the wheel unit establishes and records a first reference pattern by measuring the power of the received messages. This first reference pattern characterizes the position of the wheel unit in the motor vehicle.

[0025] - A first transmission step, during which the central processing unit re-sends the series of messages sent during the first preliminary configuration step.

[0026] - A first evaluation step performed by the wheel unit, during which a first evaluation pattern is established by measuring the power of the series of messages received during the first transmission step, and

[0027] - A first comparison step, during which the first evaluation pattern is compared with the first reference pattern in order to determine whether the position of the wheel has changed.

[0028] Thus, the method according to the invention provides a simple and effective way to limit the number of procedures for determining the position of the wheel unit, and thus limit the battery drain on each wheel unit.

[0029] Other optional features, taken alone or in combination, of the method according to the invention:

[0030] - The method at least includes:

[0031] - A second preliminary configuration step, during which the wheel unit sends a series of messages to the central unit via the communication component. This series of messages is sent according to the pre-determined instantaneous angular position of the associated wheel while the vehicle is in motion, and the central unit establishes and records a second reference pattern by measuring the power of the received messages.

[0032] - A second transmission step, during which the wheel unit re-sends the series of messages sent during the second preliminary configuration step.

[0033] - A second evaluation step, during which the central unit establishes a second evaluation pattern by measuring the power of a series of messages sent during the second transmission step.

[0034] - A second comparison step, during which the central processing unit compares the second evaluation pattern with the second reference pattern in order to determine whether the position of the wheel has changed. These second steps make it possible to enhance the reliability of the method by doubling the evaluation and reference patterns;

[0035] - The first comparison step is performed by the wheel unit;

[0036] - The first comparison step is performed by the central unit; the burden of the first comparison step is borne by the central unit in order to relieve the burden on the battery of the wheel unit;

[0037] - The motor vehicle has a plurality of central processing units, each central processing unit being designed to communicate with at least one wheel unit via a two-way communication component in order to merge the reference pattern and the evaluation pattern;

[0038] - The messages that allow the establishment of the reference pattern and the evaluation pattern each include an identification reference; this feature makes it possible to overcome the problem that the message has not been received and to continue the program in an appropriate degraded pattern;

[0039] - The method is applicable to a motor vehicle having at least one speed sensor, the speed sensor being designed to indicate to the central unit the instantaneous angular position of the wheel; the speed sensor has the advantage of saving power and resources of the wheel unit, and the wheel unit does not have to provide and transmit data on the angular position of the wheel;

[0040] - The method includes a positioning step, the positioning step being intended to determine the position of the wheel on the motor vehicle and, if the position of the wheel has been estimated to have changed during the first comparison step and / or the second comparison step, to perform the positioning step.

[0041] - The method is applied to a motor vehicle having a plurality of wheels, each wheel being associated with a wheel unit.

[0042] The invention also relates to a motor vehicle comprising at least one central processing unit, at least one wheel unit and at least one two-way radio frequency communication component, the wheel unit including the electronic components of the sensors and the wheel unit being mounted on a wheel of the motor vehicle, the two-way radio frequency communication component being designed to ensure communication between the wheel unit and the central processing unit, the central processing unit and / or the wheel unit and / or the communication component being appropriately programmed to implement the above method. Description of the Drawings

[0043] With reference to the accompanying drawings, other features and advantages of the invention will become apparent on reading the following description, in which:

[0044] Figure 1 shows a schematic view of a motor vehicle equipped with a communication component unit to which the method according to the invention is applied;

[0045] Figure 2 shows a flowchart of a first embodiment of the method according to the invention;

[0046] ​​​Figure 3 depicts, in the form of a diagram, a first reference pattern and a first evaluation pattern associated with the left front wheel of a vehicle, wherein the position of the wheel involved remains unchanged;

[0047] Figure 4 depicts, in the form of a diagram, a first reference pattern and a first evaluation pattern associated with the right front wheel of a vehicle, wherein the position of the wheel involved remains unchanged;

[0048] Figure 5 depicts, in the form of a diagram, a first reference pattern and a first evaluation pattern associated with the left rear wheel of a vehicle, wherein the position of the wheel involved remains unchanged;

[0049] Figure 6 depicts, in the form of a diagram, a first reference pattern and a first evaluation pattern associated with the right rear wheel of a vehicle, wherein the position of the wheel involved remains unchanged;

[0050] Figure 7 depicts, in the form of a diagram, a first reference pattern and a first evaluation pattern associated with the right front wheel of a vehicle, wherein the position of the wheel involved has changed;

[0051] Figure 8 shows a flowchart of a second embodiment of the method according to the present invention;

[0052] Figure 9 shows a flowchart of a third embodiment of the method according to the present invention.

[0053] For clarity, in all the drawings, the same or similar elements are denoted by the same or similar reference numerals. DETAILED DESCRIPTION

[0054] Figure 1 depicts a motor vehicle 10 equipped with: a central processing unit 12; four wheel units 14a, 14b, 14c, 14d, each wheel unit being mounted on an associated wheel 16a, 16b, 16c, 16d; and a two-way communication component 18.

[0055] The central unit 12 particularly includes an electronic processor and a memory abbreviated as "ECU" (Electronic Control Unit).

[0056] Each wheel unit 14a, 14b, 14c, 14d includes an electronic housing that contains a sensor assembly dedicated to measuring parameters such as the radial acceleration of the associated wheel, the pressure and temperature of the tire equipped on the associated wheel. Each wheel unit 14a, 14b, 14c, 14d also has a battery and a memory (which are not shown).​​​​​​

[0057] In addition, the motor vehicle 10 has four speed sensors 22a, 22b, 22c, 22d which are mounted near each associated wheel 16a, 16b, 16c, 16d and are intended to transmit the instantaneous angular position and speed of the associated wheel to the central unit 12 via the communication component 18.

[0058] The communication component 18 allows two-way exchange of messages or signals between the central unit 12 and each wheel unit 14a, 14b, 14c, 14d.

[0059] To this end, the communication component 18 has a transmitter-receiver 24 associated with the central unit 12 and four transmitter-receivers 26a, 26b, 26c, 26d respectively associated with one wheel unit 14a, 14b, 14c, 14d.

[0060] The messages exchanged between the central unit 12 and each wheel unit 14a, 14b, 14c, 14d particularly include data characterizing the operating parameters of each wheel 16a, 16b, 16c, 16d and the identification code of each wheel unit 14a, 14b, 14c, 14d.

[0061] The communication is carried out according to a communication protocol for short-range two-way data exchange using ultra-high frequency or "UHF" radio waves. Preferably, the method according to the invention uses a type of communication protocol which makes it possible to immediately send a message called a "scan request" in response to a received message called a "broadcast".

[0062] According to Figure 2 a first embodiment of the invention shown, the method for detecting a change in the position of a wheel includes a first preliminary configuration step E0-1 during which the central unit 12 successively sends a series of messages to each wheel unit 14a, 14b, 14c, 14d via the communication component 18 from one wheel unit 14a, 14b, 14c, 14d to the next.

[0063] The first preliminary step E0-1 is carried out at the end of a first program for determining the position of the wheel units 14a, 14b, 14c, 14d which starts from initialization or, repeatedly, from a position update request after detection of a change in the position of at least one wheel unit 14a, 14b, 14c, 14d. The positioning program makes it possible to establish a reference position for each wheel unit 14a, 14b, 14c, 14d.

[0064] Each wheel unit 14a, 14b, 14c, 14d respectively establishes and records in its memory a first reference pattern MR1a, MR1b, MR1c, MR1d, asFigures 3 to 6 as shown, which characterizes the position of the wheel unit in the motor vehicle 10. The starting hypothesis is that when establishing the reference pattern, the positions of each of the wheels 16a, 16b, 16c, 16d are known and correct.

[0065] More specifically, a first reference pattern MR1a, which corresponds to the left front wheel 16a and is shown in Figure 3 ; a first reference pattern MR1b, which corresponds to the right front wheel 16b and is shown in Figure 4 ; a first reference pattern MR1c, which corresponds to the right rear wheel 16c and is shown in Figure 5 ; and a first reference pattern MR1d, which corresponds to the left rear wheel 16d and is shown in Figure 6 .

[0066] Each of the first reference patterns MR1a, MR1b, MR1c, MR1d is established by measuring the power of the messages received previously during the first preliminary configuration step E0-1.

[0067] The power of the received messages is known in telecommunications by the acronym RSSI, which stands for Received Signal Strength Indication, and which is a measurement of the power of the received signal at the time of reception and gives an indication of the signal strength of the received signal. This power measurement is expressed in "dBm", which is an abbreviation for the power ratio (in decibels) between the measured power and 1 milliwatt.

[0068] Thus, a "pattern" refers to the distinctive characteristics of the messages or signals transmitted by the wheel units 14a, 14b, 14c, 14d or by the central unit 12. Each pattern is specific to the position in the motor vehicle 10 of the associated wheel unit 14a, 14b, 14c, 14d that sends or receives the message.

[0069] As can be seen from Figures 3 to 6 , the first reference patterns MR1a, MR1b, MR1c, MR1d take the form of a plot in the form of a coordinate graph, where the horizontal axis indicates the order (rang) of the "RSSI" measurements of the synchronous message transmissions from a predefined maximum set (in this case 20), and the vertical axis indicates the power of the message or signal or "RSSI" (measured in dBm).

[0070] According to the embodiments described in this specification, each of the first reference patterns MR1a, MR1b, MR1c, MR1d includes twenty synchronous "RSSI" measurements per revolution of the wheel, i.e., based on the predefined angular positions of the associated wheels 16a, 16b, 16c, 16d about their axes of rotation.

[0071] Preferably, the transmission of the messages is evenly distributed over a 360-degree rotation of the wheel.

[0072] However, there may be technical limitations in implementing such a preferred example. For example, in the case of too high a vehicle speed, there may not be enough time to transmit twenty messages evenly distributed over a single rotation of the wheel. In such a case, these transmissions can be distributed over several rotations. In addition, there is nothing to prevent a non-uniform angular distribution of the message transmissions. Generally speaking, it is sufficient to associate the message transmission order with an angular position that is predefined in advance or defined on-site and stored by the transmitter, such that the message transmission can be repeated based on a reference pattern for the next evaluation pattern. For example, it is conceivable to transmit a series of messages over several rotations of the wheel, yet the transmissions in different orders are ultimately synchronized to the same angular position.

[0073] Advantageously, the messages are synchronized by directly interpreting the data provided by the speed sensors 22a, 22b, 22c, 22d associated with the wheels 16a, 16b, 16c, 16d under discussion. The synchronization of the messages by the speed sensors 22a, 22b, 22c, 22d provides an advantage in terms of reliability due to the stability of the data or signals transmitted by the speed sensors 22a, 22b, 22c, 22d, and also provides an advantage in terms of saving energy and resources of the wheel units 14a, 14b, 14c, 14d, which do not have to supply and transmit data on the angular position of the wheel.

[0074] Still according to the first embodiment of the present invention, the method includes a first transmission step E1-1, during which the central unit 12 re-transmits this series of messages sent during the first preliminary configuration step E0-1 to each of the wheel units 14a, 14b, 14c, 14d.

[0075] After the first transmission step E1-1 is a first evaluation step E2-1, during which each of the wheel units 14a, 14b, 14c, 14d respectively establishes a first evaluation pattern ME1a, ME1b, ME1c, ME1d by measuring the power of this series of messages received during the previous first transmission step E1-1, as Figures 3 to 6 shown.

[0076] More specifically, the first evaluation pattern ME1a, which corresponds to the left front wheel 16a and is shown in Figure 3 ; the first evaluation pattern ME1b, which corresponds to the right front wheel 16b and is shown in Figure 4 ; the first evaluation pattern ME1c, which corresponds to the right rear wheel 16c and is shown in Figure 5 ; and the first evaluation pattern ME1d, which corresponds to the left rear wheel 16d and is shown inFigure 6 in

[0077] The messages allowing the establishment of the reference pattern and the evaluation pattern each include an identification reference. This identification reference makes it possible to specifically identify each message, so that the evaluation pattern and the reference pattern can be established in the same way. Due to the randomness of wireless communication, it may happen that some messages are not received. Identifying each message in a series of messages allows each wheel unit to rearrange the evaluation pattern and the reference pattern in pairs and reject individual objects.

[0078] This feature makes it possible to overcome the problem of non-received messages and continue the procedure in an appropriate degraded pattern.

[0079] After the first evaluation step E2-1, the method includes a first comparison step E3-1, during which each wheel unit 14a, 14b, 14c, 14d compares the first evaluation pattern ME1a, ME1b, ME1c, ME1d with the associated first reference pattern MR1a, MR1b, MR1c, MR1d recorded in its memory in order to determine whether the position of the wheels 16a, 16b, 16c, 16d involved has changed in the motor vehicle 10.

[0080] According to a preferred embodiment, the first evaluation pattern ME1a, ME1b, ME1c, ME1d is compared with the associated first reference pattern MR1a, MR1b, MR1c, MR1d by an algorithm based on the least squares method.

[0081] As Figure 7 shown, if the distance between the first evaluation pattern ME1a, ME1b, ME1c, ME1d and the first reference pattern MR1a, MR1b, MR1c, MR1d exceeds a predetermined decision threshold, the algorithm concludes that the position of the wheels 16a, 16b, 16c, 16d under discussion has changed, and a positioning step E4 for determining the position of the wheels 16a, 16b, 16c, 16d of the motor vehicle 10 is executed. This positioning step E4 known from the prior art is not the core of the present invention and will therefore not be described in more detail.

[0082] On the contrary, referring Figures 3 to 6 to, if the distance between the first evaluation pattern ME1a, ME1b, ME1c, ME1d and the first reference pattern MR1a, MR1b, MR1c, MR1d does not exceed a predetermined decision threshold, the algorithm concludes that the position of the wheels 16a, 16b, 16c, 16d under discussion has not changed, and therefore the positioning step E4 for determining the position of the wheels 16a, 16b, 16c, 16d is not required.

[0083] Based on the number of measurements performed for establishing the first evaluation patterns ME1a, ME1b, ME1c, ME1d per wheel rotation, and based on the measurement noise level measured in "dBm", a decision threshold is determined in advance. It is not necessary to know the measurement noise level in advance, and thus a threshold such as 10 dBm is fixed in advance. By way of non-limiting example, the noise can be evaluated in order to adjust the decision threshold more precisely.

[0084] According to a variant of the first embodiment of the invention, each wheel unit 14a, 14b, 14c, 14d sends the first evaluation patterns ME1a, ME1b, ME1c, ME1d and the first reference patterns MR1a, MR1b, MR1c, MR1d to the central unit 12, and the central unit 12 performs a first comparison stage E3-1 in order to relieve the processing burden of the wheel units 14a, 14b, 14c, 14d. To this end, after each message has been received by the wheel unit in question, each wheel unit 14a, 14b, 14c, 14d re-sends the RSSI messages it has collected as a system response to the central unit 12.

[0085] The detection method according to the invention includes a second embodiment, according to which, as in the above first embodiment, these messages are sent from the central unit 12 to each wheel unit 14a, 14b, 14c, 14d, and these messages are also sent from each wheel unit 14a, 14b, 14c, 14d to the central unit 12 in order to increase the robustness of the method.

[0086] More specifically, according to the second embodiment, the method includes a first preliminary configuration step E0-1, a first transmission step E1-1, a first evaluation step E2-1 and a first comparison step E3-1, which steps have the same reference numerals as the steps described above for the first embodiment and thus will not be described in detail so as not to unnecessarily burden the description.

[0087] In addition, according to Figure 8 the second embodiment shown, the method includes a second preliminary configuration step E0-2, during which each wheel unit 14a, 14b, 14c, 14d sends a series of messages to the central unit 12 successively via the communication component 18. The messages sent for each wheel unit during this second configuration step E0-2 are sent as a response or reaction to the reception of the messages sent by the central unit 12 during the first configuration step E0-1.

[0088] The central unit 12 establishes and records second reference patterns MR2a, MR2b, MR2c, MR2d (not shown) by measuring the power of the messages received during the second preliminary configuration step E0-2, which characterize the positions of the transmitting wheel units 14a, 14b, 14c, 14d.

[0089] Still according to the second embodiment, the method includes a second transmission step E1-2, during which each wheel unit 14a, 14b, 14c, 14d re-transmits to the central unit 12 the series of messages transmitted in the previous second preliminary configuration step E0-2.

[0090] After the second transmission step E1-2 is a second evaluation step E2-2, during which the central unit 12 establishes second evaluation patterns ME2a, ME2b, ME2c, ME2d (not shown) by measuring the power of the series of messages received during the previous second transmission step E1-2.

[0091] After the second evaluation step E2-2, the method includes a second comparison step E3-2, during which the central unit 12 compares the second evaluation patterns ME2a, ME2b, ME2c, ME2d with the associated second reference patterns MR2a, MR2b, MR2c, MR2d recorded in its memory in order to determine whether the positions of the wheels 16a, 16b, 16c, 16d in question have changed in the motor vehicle 10.

[0092] The second evaluation patterns ME2a, ME2b, ME2c, ME2d are compared with the associated second reference patterns MR2a, MR2b, MR2c, MR2d by an algorithm based on the least squares method. If the distance between the second evaluation patterns ME2a, ME2b, ME2c, ME2d and the second reference patterns MR2a, MR2b, MR2c, MR2d exceeds a predetermined decision threshold, the algorithm concludes that the positions of the wheels 16a, 16b, 16c, 16d in question have changed, and a positioning step E4 for determining the positions of the wheels 16a, 16b, 16c, 16d of the motor vehicle 10 is performed.

[0093] Conversely, if the distance between the second evaluation patterns ME2a, ME2b, ME2c, ME2d and the second reference patterns MR2a, MR2b, MR2c, MR2d does not exceed the predetermined decision threshold, the algorithm concludes that the positions of the wheels 16a, 16b, 16c, 16d in question have not changed, and thus the positioning step E4 for determining the positions of the wheels 16a, 16b, 16c, 16d is not required.

[0094] Similar to the first embodiment of the method, the decision threshold is predetermined, just as the number of messages synchronously sent by the wheel units 14a, 14b, 14c, 14d is also predetermined.

[0095] According to an exemplary embodiment of the second embodiment of the present invention, the position change of at least one of the wheels 16a, 16b, 16c, 16d is preferentially detected. That is to say, if the first comparison step E3-1 or the second comparison step E3-2 estimates that the position of one of the wheels has changed, the positioning step E4 for determining the positions of the wheels 16a, 16b, 16c, 16d is necessary.

[0096] On the contrary, in an implementation variant, if the first comparison step E3-1 and the second comparison step E3-2 estimate that the position of one of the wheels has changed, the positioning step E4 for determining the positions of the wheels 16a, 16b, 16c, 16d is necessary. The detection method according to the present invention includes Figure 9 the third embodiment shown. Except that the first comparison step E3-1 is not performed by the wheel units 14a, 14b, 14c, 14d but by the central unit 12, this third embodiment is the same as the second embodiment described above.

[0097] For this purpose, each wheel unit 14a, 14b, 14c, 14d sends a first evaluation pattern ME1a, ME1b, ME1c, ME1d and a first reference pattern MR1a, MR1b, MR1c, MR1d to the central unit 12, and the central unit 12 performs the first comparison phase E3-1.

[0098] Advantageously, the third embodiment of the method can reduce the processing burden of the wheel units 14a, 14b, 14c, 14d.

[0099] According to an embodiment variant (which is not shown and is common to the above three embodiments), the motor vehicle 10 has a plurality of central processing units 12, and each central processing unit is designed to communicate with each wheel unit 14a, 14b, 14c, 14d via a two-way communication component 18. This variant enables the "size" of each reference pattern MR1a, MR1b, MR1c, MR1d, MR2a, MR2b, MR2c, MR2d and each evaluation pattern ME1a, ME1b, ME1c, ME1d, ME2a, ME2b, ME2c, Me2d to be multiplied by the size of each central unit 12, thereby combining each reference pattern MR1a, MR1b, MR1c, MR1d, MR2a, MR2b, MR2c, MR2d and each evaluation pattern ME1a, ME1b, ME1c, ME1d, ME2a, ME2b.

[0100] The detection method according to the present invention provides a reliable solution with a low false positive rate (i.e., a change in the wheel position is not detected).

[0101] Furthermore, the method according to the present invention is particularly suitable for implementation in a BLE type (representing " LowEnergy", "Bluetooth Low Energy") environment and provides the option of two-way exchange between the central unit 12 and the wheel units 14a, 14b, 14c, 14d.

Claims

1. A method for detecting a change in position of at least one wheel (16a, 16b, 16c, 16d) of a motor vehicle (10), said vehicle having: - at least one central processing unit (12), - at least one wheel unit (14a, 14b, 14c, 14d), said wheel unit including an electronic assembly of sensors and said wheel unit being mounted on said wheel (16a, 16b, 16c, 16d) of said motor vehicle (10), and - at least one two-way radio frequency communication assembly (18) designed to ensure communication between said wheel unit (14a, 14b, 14c, 14d) and said central processing unit (12), It is characterized in that The method at least includes: - A first preliminary configuration step (E0-1) during which said central processing unit (12) sends a series of messages to said wheel unit (14a, 14b, 14c, 14d) via said communication assembly (18), said series of messages being sent according to a predetermined instantaneous angular position of the associated wheel (16a, 16b, 16c, 16d) while the vehicle (10) is in motion, and said wheel unit (14a, 14b, 14c, 14d) establishes and records a first reference pattern (MR1a, MR1b, MR1c, MR1d) by measuring the power of the received messages, said first reference pattern characterizing the position of said wheel unit in said motor vehicle (10), - A first transmission step (E1-1) during which said central processing unit (12) re-sends said series of messages sent during said first preliminary configuration step (E0-1), - A first evaluation step (E2-1) performed by said wheel unit (14a, 14b, 14c, 14d) during which a first evaluation pattern (ME1a, ME1b, ME1c, ME1d) is established by measuring the power of said series of messages received during said first transmission step (E1-1), and - A first comparison step (E3-1) during which said first evaluation pattern (ME1a, ME1b, ME1c, ME1d) is compared with said first reference pattern (MR1a, MR1b, MR1c, MR1d) in order to determine whether the position of said wheel (16a, 16b, 16c, 16d) has changed.

2. The detection method according to claim 1, characterized in that, It at least includes: - A second preliminary configuration step (E0-2) during which said wheel unit (14a, 14b, 14c, 14d) sends a series of messages to said central processing unit (12) via said communication assembly (18), said series of messages being sent according to a predetermined instantaneous angular position of the associated wheel (16a, 16b, 16c, 16d) while the vehicle (10) is in motion, and said central processing unit (12) establishes and records a second reference pattern (MR2a, MR2b, MR2c, MR2d) by measuring the power of the received messages, - A second transmission step (E1-2), during which the wheel units (14a, 14b, 14c, 14d) retransmit the series of messages sent during the second preliminary configuration step (E0-2). - A second evaluation step (E2-2), during which the central processing unit (12) establishes a second evaluation pattern (ME2a, ME2b, ME2c, ME2d) by measuring the power of a series of messages sent during the second transmission step (E1-2). - A second comparison step (E3-2), during which the central processing unit (12) compares the second evaluation pattern (ME2a, ME2b, ME2c, ME2d) with the second reference pattern (MR2a, MR2b, MR2c, Mr2d) in order to determine whether the position of the wheels (16a, 16b, 16c, 16d) has changed.

3. The detection method according to claim 1 or 2, characterized in that The first comparison step (E3-1) is performed by the wheel units (14a, 14b, 14c, 14d).

4. The detection method according to claim 1 or 2, characterized in that, The first comparison step (E3-1) is performed by the central processing unit (12).

5. The detection method according to claim 1 or 2, characterized in that, The motor vehicle (10) has a plurality of central processing units (12), each central processing unit (12) being designed to communicate with the at least one wheel unit (14a, 14b, 14c, 14d) via the two-way radio frequency communication component (18) to merge the reference pattern and the evaluation pattern.

6. The detection method according to claim 1 or 2, characterized in that The messages that enable the establishment of the reference pattern and the evaluation pattern each include an identification reference.

7. The detection method according to claim 1 or 2, which is applicable to a motor vehicle (10) having at least one speed sensor (22a, 22b, 22c, 22d), the speed sensor being designed to indicate the instantaneous angular position of the wheels (16a, 16b, 16c, 16d) to the central processing unit (12).

8. The detection method according to claim 1 or 2, characterized in that, It includes a positioning step (E4), which aims to determine the position of the wheels (16a, 16b, 16c, 16d) on the motor vehicle (10), and the positioning step is executed if the position of the wheels (16a, 16b, 16c, 16d) has been estimated to have changed during the first comparison step (E3-1) and / or the second comparison step (E3-2).

9. The detection method according to claim 1 or 2, which is applicable to a motor vehicle (10) having a plurality of wheels (16a, 16b, 16c, 16d), each wheel being associated with a wheel unit (14a, 14b, 14c, 14d).

10. A motor vehicle (10) comprising at least one central processing unit (12), at least one wheel unit (14a, 14b, 14c, 14d) and at least one two-way radio communication component (18), said wheel unit comprising an electronic assembly of sensors and said wheel unit being mounted on the wheels (16a, 16b, 16c, 16d) of the motor vehicle (10), said two-way radio communication component being designed to ensure communication between the wheel unit (14a, 14b, 14c, 14d) and the central processing unit (12), characterized in that, The central processing unit (12) and / or the wheel units (14a, 14b, 14c, 14d) and / or the communication component (18) are appropriately programmed to implement the method according to any one of claims 1 to 9.

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