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

Abstract

The 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) comprising an electronic assembly of sensors and mounted on said wheel (16a, 16b, 16c, 16d) and at least one bidirectional communication assembly (18), characterized in that it notably 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 being characteristic of the actual position of the wheel unit in the motor vehicle (10).

Description

Technical Field

[0001] This patent application relates to a method for detecting positional changes of at least one wheel of a motor vehicle, particularly applicable to the field of motor vehicle equipment. Background Technology

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

[0003] Such a monitoring system typically includes: a central processing unit; wheel units, each equipped with an associated wheel of the vehicle; and a radio frequency communication component suitable for ensuring 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 electronic components for sensors to detect abnormal conditions in the wheel, in particular. These sensors may include tire 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 the mobile terminal and each wheel unit. These messages specifically include data characterizing the operating parameters of each wheel and an identification code for each wheel unit.

[0008] Communication is conducted according to a communication protocol that uses ultra-high frequency (UHF) or "UHF" radio waves for short-range, two-way data exchange, for example, according to... Type of communication protocol.

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

[0010] The position of the wheel unit relative to the position of the wheel in the vehicle is usually verified at the beginning of a new driving cycle, and according to the prior art, it is necessary to periodically send messages from the wheel unit to the central unit to synchronize with the determined angular position.

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

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

[0013] However, the battery in each wheel unit has a limited lifespan and is not designed to be recharged. Therefore, power consumption must be limited to optimize the lifespan of the battery in each wheel unit.

[0014] Furthermore, it should be noted that when verifying the wheel unit position at the beginning of each driving cycle, this yields an unchanged wheel unit position most of the time. This is because wheels are only replaced or rotated once or twice a year on average, especially when rotating between winter and summer tires, which represents less than one percent of the effective wheel unit position change in the wheel unit alignment procedure.

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

[0016] While this method allows for the restriction of the procedure used to verify the position of the wheel unit, it is complex to implement and requires auxiliary components such as a dedicated low-frequency antenna, a low-frequency controller, and dedicated wiring for each wheel unit.

[0017] Existing technologies do not provide a simple and reliable solution to ensure the detection of positional changes of wheel units with low power consumption. Summary of the Invention

[0018] The present invention aims to address these shortcomings.

[0019] This and other objectives will become apparent from the following description, achieved by a method for detecting changes 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, the wheel unit including electronic components of a sensor, and the wheel unit being mounted on the wheel of a motor vehicle, and

[0022] - At least one device for measuring the angular position of the wheel, and

[0023] - At least one bidirectional radio frequency communication component, designed to ensure communication between the wheel unit and the central unit.

[0024] The method is characterized by comprising at least:

[0025] - In the first preliminary configuration step, during which the wheel unit sends a series of messages to the central unit via a communication component, these messages are sent while the vehicle is in motion and are synchronized with the angular position of the associated wheels, and the central unit establishes and records a first reference pattern by measuring the power of the received messages, the first reference pattern representing the position of the wheel unit in the motor vehicle.

[0026] - First transmission step, during which the wheel unit repeats the transmission of this series of messages sent during the first preliminary configuration step.

[0027] - A first evaluation step performed by the central unit, during which the central unit establishes a first evaluation pattern by measuring the power of the series of messages received during the first transmission step, and

[0028] - A first comparison step performed by the central unit, during which a first evaluation pattern is compared with a first reference pattern to determine whether the position of the wheel has changed.

[0029] Therefore, the method according to the invention provides a simple and effective way to limit the number of procedures used to determine the position of the wheel unit, and thus limit the battery consumption for each wheel unit.

[0030] Other optional features employed individually or in combination in the method according to the invention:

[0031] - The synchronization of the transmission of the series of messages with the angular position of the associated wheel is achieved by sending the messages sequentially with an inter-message delay determined based on the rotational speed of the wheel, so as to cover at least one revolution of the wheel involved.

[0032] The rotational speed of the wheels is provided by a speed sensor mounted on the vehicle near the associated wheel. This feature allows for the avoidance of depleting the wheel speed measurement device powered by the wheel unit's battery.

[0033] - The rotational speed of the wheel is provided by a device for measuring the angular position of the wheel, which is an accelerometer mounted on the associated wheel unit;

[0034] - The synchronization of the transmission of the series of messages with the associated angular position of the wheel is achieved by transmitting the messages sequentially based on a predetermined instantaneous angular direction of the wheel, the angular direction being provided by a device for measuring the angular position of the wheel;

[0035] The method includes at least:

[0036] - In the second preliminary configuration step, during which the central unit sends a series of messages to the wheel units via a communication component, these messages are sent while the vehicle is in motion and are synchronized with the angular positions of the associated wheels. The wheel units establish and record a second reference pattern by measuring the power of the received messages. This second reference pattern characterizes the position of the wheel unit within the motor vehicle.

[0037] - Second transmission step, during which the central unit repeats the transmission of this series of messages sent during the second preliminary configuration step.

[0038] - A second evaluation step, during which the wheel unit establishes a second evaluation pattern by measuring the power of a series of messages sent during the second transmission step, and

[0039] - A second comparison step, during which the wheel unit compares the second evaluation pattern with the second reference pattern to determine whether the wheel's position has changed. This feature makes the method more reliable by doubling the number of messages sent.

[0040] - The vehicle has multiple central processing units, each of which is designed to communicate with at least one wheel unit via a bidirectional communication component to merge the reference pattern and the evaluation pattern;

[0041] - The messages that allow the establishment of the reference style and the evaluation style each include an identification reference; therefore, if a message is lost, its identification reference can be used to recover the message;

[0042] The method includes a positioning step designed to determine the position of the wheel on the motor vehicle, and the positioning step is performed if the position of the wheel has been estimated to have changed during the first comparison step and / or the second comparison step.

[0043] - This method is applied to motor vehicles with multiple wheels, each wheel being associated with a wheel unit.

[0044] The present invention also relates to a motor vehicle comprising at least one central processing unit, at least one wheel unit and at least one bidirectional radio frequency communication component, the wheel unit comprising electronic components of sensors and mounted on the wheels of the motor vehicle, the bidirectional radio frequency communication component being designed to ensure communication between the wheel unit and the central processing unit, characterized in that the central processing unit and / or the wheel unit and / or the communication component are appropriately programmed to implement the above-described method. Attached Figure Description

[0045] Referring to the accompanying drawings, other features and advantages of the invention will become apparent from the following description, wherein:

[0046] [ Figure 1 [: This is a schematic diagram of a motor vehicle equipped with a communication component unit, to which the method according to the present invention is applied;]

[0047] [ Figure 2 [ ]: This is a flowchart of a first embodiment of the method according to the present invention;

[0048] [ Figure 3 [The first reference pattern and the first evaluation pattern associated with the left front wheel of the vehicle are depicted in the form of a diagram, in which the position of the wheel involved remains unchanged;]

[0049] [ Figure 4 [The first reference pattern and the first evaluation pattern associated with the right front wheel of the vehicle are depicted in the form of a diagram, in which the position of the wheel involved remains unchanged;]

[0050] [ Figure 5 [The first reference pattern and the first evaluation pattern associated with the left rear wheel of the vehicle are depicted in the form of a diagram, in which the position of the wheel involved remains unchanged;]

[0051] [ Figure 6 [The first reference pattern and the first evaluation pattern associated with the right rear wheel of the vehicle are depicted in the form of a diagram, in which the position of the wheel involved remains unchanged;]

[0052] [ Figure 7 [The first reference pattern and the first evaluation pattern associated with the right front wheel of the vehicle are depicted in the form of a diagram, in which the position of the wheel involved has been changed;]

[0053] [ Figure 8 [A flowchart illustrating a second embodiment of the method according to the present invention is shown;]

[0054] For clarity, in all the accompanying drawings, the same or similar elements are indicated by the same or similar reference numerals. Detailed Implementation

[0055] Figure 1 The vehicle 10 is depicted, which is equipped with: a central processing unit 12; four wheel units 14a, 14b, 14c, 14d, each wheel unit being mounted on associated wheels 16a, 16b, 16c, 16d; and a two-way communication component 18.

[0056] The central unit 12 includes, in particular, an electronic processor and a memory, abbreviated as "ECU" (Electronic Control Unit).

[0057] Each wheel unit 14a, 14b, 14c, 14d includes an electronic housing containing sensors specifically designed to measure parameters such as tire pressure and temperature of the associated wheel. Each wheel unit 14a, 14b, 14c, 14d also includes a battery and memory (not shown).

[0058] Furthermore, each wheel unit 14a, 14b, 14c, 14d includes accelerometers 15a, 15b, 15c, 15d, which constitute a first device for measuring the rotational speed of the associated wheels 16a, 16b, 16c, 16d. Each accelerometer 15a, 15b, 15c, 15d is capable of providing a modulation signal that characterizes the value of gravity and thus the angular position of each accelerometer, and the modulation signal, whose frequency is equal to the rotational frequency of the wheel, also enables the calculation of the rotational speed of the associated wheels 16a, 16b, 16c, 16d.

[0059] The motor vehicle 10 also includes four speed sensors 22a, 22b, 22c, and 22d, which form a second device for measuring the rotational speed of associated wheels 16a, 16b, 16c, and 16d. The speed sensors 22a, 22b, 22c, and 22d are mounted near each associated wheel 16a, 16b, 16c, and 16d, and are capable of transmitting the instantaneous angular position and speed of the associated wheels to the central unit 12 via the communication component 18.

[0060] The communication component 18 allows for bidirectional exchange of messages or signals between the central unit 12 and each wheel unit 14a, 14b, 14c, 14d.

[0061] For this purpose, the communication component 18 includes a transmitter-receiver 24 associated with the central unit 12 and four transmitter-receivers 26a, 26b, 26c, and 26d, each associated with a wheel unit 14a, 14b, 14c, and 14d, respectively.

[0062] The messages exchanged between the central unit 12 and each wheel unit 14a, 14b, 14c, 14d specifically 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.

[0063] Communication is conducted according to a communication protocol that uses ultra-high frequency (UHF) or "UHF" for short-range, two-way data exchange. Preferably, the method according to the invention employs... A type of communication protocol that allows a message called a "scan request" to be sent immediately in response to a received message, which is called a "broadcast".

[0064] according to Figure 2 The first embodiment of the present invention shown includes a method for detecting changes in wheel position, comprising a first preliminary configuration step E0-1, during which each wheel unit 14a, 14b, 14c, 14d sends a series of messages to the central unit 12 via a communication component 18. According to the described embodiment, the series of messages includes twenty messages.

[0065] The first preliminary step E0-1 is executed at the end of the first procedure for determining the positions of wheel units 14a, 14b, 14c, and 14d. This first procedure begins with initialization, or repeatedly with a position update request following the detection of a position change in at least one wheel unit 14a, 14b, 14c, or 14d. The positioning procedure allows a reference position to be established for each wheel unit 14a, 14b, 14c, and 14d.

[0066] Central unit 12 establishes and records the first reference patterns MR1a, MR1b, MR1c, and MR1d in its memory, respectively, as follows: Figures 3 to 6 As shown, it represents the position of the relevant wheel units 14a, 14b, 14c, and 14d in the motor vehicle 10. The initial assumption is that the position of each wheel 16a, 16b, 16c, and 16d is known and correct when the reference pattern is established.

[0067] More specifically, the first reference style MR1a corresponding to the left front wheel 16a is shown in Figure 3 In the middle; the first reference style MR1b corresponding to the right front wheel 16b is shown in Figure 4 In the middle; the first reference style MR1c corresponding to the right rear wheel 16c is shown in Figure 5 In the middle; and corresponding to the first reference style MR1d of the left rear wheel 16d, it is shown in Figure 6 middle.

[0068] Each first reference pattern MR1a, MR1b, MR1c, MR1d is established by measuring the power of messages previously received during the first preliminary configuration step E0-1.

[0069] The power of a received message is known in telecommunications as the acronym RSSI, which stands for Received Signal Strength Indication. It is a measurement of the power of the received signal at the time of reception and provides 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.

[0070] Therefore, a “pattern” refers to the unique characteristics of a message or signal transmitted by wheel units 14a, 14b, 14c, 14d or by the central unit 12. Each pattern represents the position of the associated wheel units 14a, 14b, 14c, 14d in the motor vehicle 10 for sending or receiving a message.

[0071] from Figures 3 to 6 As can be seen, the first reference patterns MR1a, MR1b, MR1c, and MR1d are depicted in the form of a coordinate graph, where the horizontal axis indicates the order of the RSSI measurement results of synchronous message transmissions from a predefined maximum set (20 in this case), and the vertical axis indicates the power or RSSI of the message or signal (measured in dBm).

[0072] According to the embodiments described in this specification, each first reference pattern MR1a, MR1b, MR1c, MR1d includes twenty synchronous RSSI measurements per revolution of the wheel.

[0073] Preferably, the message transmission is evenly distributed along one full rotation of the wheel in 360 degrees.

[0074] However, implementing this preferred example may have technical limitations. For instance, at excessively high vehicle speeds, there might not be enough time to send twenty messages evenly distributed over a single rotation of the wheel. In such cases, these transmissions could be spread over several rotations. Furthermore, nothing prevents a non-uniform angular distribution of message transmissions. Generally, associating the message transmission order with pre-defined or on-site defined angular positions stored by the transmitter is sufficient, allowing message transmissions to be repeated based on a reference pattern used for the next evaluation pattern. For example, one could envision sending a series of messages over several rotations of the wheel, where different sequences of transmissions eventually synchronize to the same angular position.

[0075] Still according to a first embodiment of the invention, the method includes a first transmission step E1-1, during which each wheel unit 14a, 14b, 14c, 14d retransmits to the central unit 12 the series of messages transmitted during the first preliminary configuration step E0-1.

[0076] Following the first transmission step E1-1 is the first evaluation step E2-1, during which the central unit 12 establishes first evaluation patterns ME1a, ME1b, ME1c, and ME1d respectively by measuring the power of the series of messages received during the previous first transmission step E1-1. These patterns are depicted in... Figures 3 to 6 middle.

[0077] More specifically, the first evaluation pattern ME1a corresponding to the left front wheel 16a is shown in Figure 3 In the middle; the first evaluation pattern ME1b corresponding to the right front wheel 16b is shown in Figure 4 In the middle; the first evaluation style ME1c corresponding to the right rear wheel 16c is shown in Figure 5 In the middle; and corresponding to the first evaluation style ME1d of the left rear wheel 16d, it is shown in Figure 6 middle.

[0078] Each message that allows the establishment of a reference pattern and an evaluation pattern includes an identification reference. This identification reference allows each message to be specifically identified, thereby establishing the evaluation pattern and the reference pattern in the same manner. Due to the randomness of wireless communication, some messages may not be 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.

[0079] This feature allows the problem of not receiving messages to be overcome and the procedure to continue with an appropriate degradation pattern.

[0080] Following the first evaluation step E2-1, the method includes a first comparison step E3-1, during which the central unit 12 compares each first evaluation pattern ME1a, ME1b, ME1c, ME1d with an associated first reference pattern MR1a, MR1b, MR1c, MR1d recorded in its memory to determine whether the wheels involved 16a, 16b, 16c, 16d have changed position in the motor vehicle 10.

[0081] According to a preferred embodiment, each first evaluation style ME1a, ME1b, ME1c, ME1d is compared with the associated first reference styles MR1a, MR1b, MR1c, MR1d using a least squares-based algorithm.

[0082] like Figure 7 As shown, if the distance between each first evaluation pattern ME1a, ME1b, ME1c, ME1d and the associated first reference pattern MR1a, MR1b, MR1c, MR1d exceeds a predetermined decision threshold, the algorithm concludes that the involved wheels 16a, 16b, 16c, 16d have changed position, and performs positioning step E4 to determine the position of the wheels 16a, 16b, 16c, 16d of the motor vehicle 10. This positioning step E4, known from the prior art, is not the core of the present invention and will therefore not be described in further detail.

[0083] Conversely, refer to Figures 3 to 6If the distance between each first evaluation pattern ME1a, ME1b, ME1c, ME1d and the associated first reference pattern MR1a, MR1b, MR1c, MR1d does not exceed a predetermined decision threshold, the algorithm concludes that the positions of the involved wheels 16a, 16b, 16c, 16d have not changed, and therefore the positioning step E4 for determining the positions of wheels 16a, 16b, 16c, 16d is not required.

[0084] The decision threshold is predetermined based on the number of measurements performed per revolution of the wheel to establish the first evaluation patterns ME1a, ME1b, ME1c, ME1d, and the measurement noise level measured in dBm. The measurement noise level does not need to be known beforehand, and therefore a threshold of, for example, 10 dBm can be fixed in advance. Without limitation, the noise can be evaluated to adjust the decision threshold more precisely.

[0085] Still according to the first embodiment of the present invention, the series of messages sent during the first configuration step E0-1 and the first transmission step E1-1 are sent while the vehicle 10 is in motion, and are synchronized with the angular position of the associated wheels.

[0086] According to a first variation of the first embodiment of the invention, the synchronization of the transmission of a series of messages with the angular positions of the associated wheels 16a, 16b, 16c, 16d involves transmitting these messages sequentially with a uniform inter-message delay determined based on the rotational speeds of the associated wheels 16a, 16b, 16c, 16d, so as to cover at least one revolution of the involved wheels. For example, this inter-message delay is calculated to be fifteen milliseconds, such that twenty messages are transmitted uniformly at the angular positions of the wheels, which are successively offset by eighteen degrees. It will be noted that the fifteen-millisecond inter-message delay approximately corresponds to a speed of twenty kilometers per hour for the motor vehicle 10. For a speed of approximately sixty kilometers per hour for the motor vehicle 10, the inter-message delay is five milliseconds, so that twenty measurements are obtained for each revolution of the wheels.

[0087] The message delay is calculated by each involved wheel unit based on information relating to the wheel's rotational speed provided by each associated speed sensor 22a, 22b, 22c, 22d.

[0088] Since wheel units 14a, 14b, 14c, and 14d cannot directly access speed information from speed sensors 22a, 22b, 22c, and 22d, the central unit 12 transmits this speed information.

[0089] To this end, each wheel unit 14a, 14b, 14c, 14d sends the first message in the series at an undefined transmission angle, and the central unit 12 responds with a message providing information about the rotational speed of the wheel (provided by each associated speed sensor 22a, 22b, 22c, 22d), and then based on this speed information, each wheel unit 14a, 14b, 14c, 14d derives the inter-message delay, and thus derives the time when the next message in the series will be sent.

[0090] In a non-limiting manner, the message delay can also be calculated by each involved wheel unit 14a, 14b, 14c, 14d based on information related to the rotational speed of the wheel provided by each associated accelerometer 15a, 15b, 15c, 15d, which can be directly accessed by each wheel unit 14a, 14b, 14c, 14d.

[0091] Therefore, the first message in this series is sent to the central unit 12 from each wheel unit 14a, 14b, 14c, 14d at an undefined transmission angle, and the next message is sent according to a defined inter-message duration. The central unit 12 can potentially reorganize the received messages to correspond to a defined angular direction sequence by utilizing information provided by the associated speed sensors 22a, 22b, 22c, 22d.

[0092] According to a second variation of the first embodiment of the invention, the synchronization of the transmission of a series of messages with the angular positions of the associated wheels 16a, 16b, 16c, 16d is achieved by transmitting the messages sequentially in predetermined instantaneous angular directions, which are provided by each accelerometer 15a, 15b, 15c, 15d associated with the involved wheels 16a, 16b, 16c, 16d.

[0093] This second embodiment variant, which relies on velocity data provided by accelerometers 15a, 15b, 15c, and 15d, avoids the potential problem of angular reference drift of velocity sensors 22a, 22b, 22c, and 22d.

[0094] The detection method according to the present invention includes a second embodiment, such as... Figure 8 As shown, according to this second embodiment, messages are sent from each wheel unit 14a, 14b, 14c, 14d to the central unit 12 (as in the first embodiment described above), and from the central unit 12 to each wheel unit 14a, 14b, 14c, 14d to improve the robustness of the method.

[0095] 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. These steps are the same as those with the same reference numerals described above for the first embodiment, and therefore will not be described in detail to avoid unnecessarily increasing the burden of description.

[0096] In addition, according to Figure 8 In the second embodiment shown, the method includes a second preliminary configuration step E0-2, during which the central unit 12 sequentially sends a series of messages to each wheel unit 14a, 14b, 14c, 14d via the communication component 18. The messages sent by the central unit 12 during this second configuration step E0-2 are sent as a response or reaction to the reception of messages sent by each wheel unit 14a, 14b, 14c, 14d during the first configuration step E0-1.

[0097] Each wheel unit 14a, 14b, 14c, 14d establishes and records a second reference pattern MR2a, MR2b, MR2c, MR2d (not shown) by measuring the power of the messages received during the second preliminary configuration step E0-2. This second reference pattern characterizes the position of the receptive wheel units 14a, 14b, 14c, 14d.

[0098] Still according to the second embodiment, the method includes a second transmission step E1-2, during which the central unit 12 retransmits to each wheel unit 14a, 14b, 14c, 14d the series of messages sent in the previous second preliminary configuration step E0-2.

[0099] The second transmission step E1-2 is followed by the second evaluation step E2-2, during which each wheel unit 14a, 14b, 14c, 14d establishes a second evaluation pattern ME2a, ME2b, ME2c, ME2d (not shown) by measuring the power of the series of messages received during the previous second transmission step E1-2.

[0100] Following the second evaluation step E2-2, the method includes a second comparison step E3-2, during which each wheel unit 14a, 14b, 14c, 14d compares the second evaluation patterns ME2a, ME2b, ME2c, ME2d with associated second reference patterns MR2a, MR2b, MR2c, MR2d recorded in its memory to determine whether the position of the involved wheels 16a, 16b, 16c, 16d in the motor vehicle 10 has changed.

[0101] The second evaluation patterns ME2a, ME2b, ME2c, ME2d are compared with the associated second reference patterns MR2a, MR2b, MR2c, MR2d using a least squares-based algorithm. 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 position of the involved wheel has changed, and performs positioning step E4 to determine the position of the wheels 16a, 16b, 16c, 16d of the motor vehicle 10.

[0102] 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 a predetermined decision threshold, the algorithm concludes that the positions of the involved wheels 16a, 16b, 16c, 16d have not changed, and therefore the positioning step E4 for determining the positions of wheels 16a, 16b, 16c, 16d is not required.

[0103] Similar to the first embodiment of the method, the decision threshold is predetermined, just as the number of messages synchronously sent by the central unit 12 is also predetermined.

[0104] According to an exemplary embodiment of the second embodiment of the present invention, positional changes of at least one wheel 16a, 16b, 16c, 16d are preferentially detected. That is, 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, then the positioning step E4 for determining the position of wheels 16a, 16b, 16c, 16d is necessary.

[0105] Conversely, in the implementation of the 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, then the positioning step E4 for determining the position of wheels 16a, 16b, 16c, and 16d is necessary.

[0106] According to another embodiment variant (not shown, but common to both embodiments described above), the motor vehicle 10 includes a plurality of central processing units 12, each central processing unit being adapted to communicate with each wheel unit 14a, 14b, 14c, 14d via a bidirectional communication component 18. This variant allows 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 merging each reference pattern MR1a, MR1b, MR1c, MR1d, MR2a, MR2b, MR2c, MR2d and each evaluation pattern ME1a, ME1b, ME1c, ME1d, ME2a, ME2b.

[0107] The detection method according to the present invention provides a reliable solution that offers a low level of false positives (i.e., the change in wheel position is not detected).

[0108] The method according to the invention offers the advantage that active monitoring is not required on parts of wheel units 14a, 14b, 14c, and 14d. Specifically, such monitoring would significantly impact the energy consumption of wheel units 14a, 14b, 14c, and 14d, and would also require timely activation, thus increasing the complexity of the method.

[0109] Furthermore, the method according to the invention is particularly suitable for BLE type (representing "BLE"). Implemented in a Low Energy (Bluetooth Low Power) environment, and provides the option for bidirectional switching between the central unit 12 and the wheel units 14a, 14b, 14c, 14d.

Claims

1. A method for detecting positional changes 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), the wheel unit including electronic components of the sensor and the wheel unit mounted on the wheels (16a, 16b, 16c, 16d) of the motor vehicle (10), and - At least one device (15a, 15b, 15c, 15d) for measuring the angular position of the wheels (16a, 16b, 16c, 16d), and - At least one bidirectional radio frequency communication component (18) is designed to ensure communication between the wheel units (14a, 14b, 14c, 14d) and the central processing unit (12). Its features are, The method includes at least: - First preliminary configuration step (E0-1), during which the wheel units (14a, 14b, 14c, 14d) send a series of messages to the central processing unit (12) via the bidirectional radio frequency communication component (18). These messages are sent while the vehicle (10) is in motion and are synchronized with the angular positions of the associated wheels (16a, 16b, 16c, 16d). The central processing unit (12) establishes and records a first reference pattern (MR1a, MR1b, MR1c, MR1d) by measuring the power of the received messages. This first reference pattern characterizes the position of the wheel units (14a, 14b, 14c, 14d) within the motor vehicle (10). - First transmission step (E1-1), during which the wheel units (14a, 14b, 14c, 14d) repeat the transmission of the series of messages sent during the first preliminary configuration step (E0-1). - A first evaluation step (E2-1) performed by the central processing unit (12), during which the central processing unit (12) establishes a first evaluation pattern (ME1a, ME1b, ME1c, ME1d) by measuring the power of the series of messages received during the first transmission step (E1-1), and - A first comparison step (E3-1) performed by the central processing unit (12), during which the first evaluation pattern (ME1a, ME1b, ME1c, ME1d) is compared with the first reference pattern (MR1a, MR1b, MR1c, MR1d) to determine whether the position of the wheels (16a, 16b, 16c, 16d) has changed. - Second preliminary configuration step (E0-2), during which the central processing unit (12) sends a series of messages to the wheel units (14a, 14b, 14c, 14d) via the bidirectional radio frequency communication component (18). These messages are sent while the vehicle (10) is in motion and are synchronized with the angular positions of the associated wheels. The wheel units (14a, 14b, 14c, 14d) establish and record a second reference pattern (MR2a, MR2b, MR2c, MR2d) by measuring the power of the received messages. This second reference pattern characterizes the position of the wheel units within the motor vehicle (10). - Second transmission step (E1-2), during which the central processing unit (12) repeats the transmission of the series of messages sent during the second preliminary configuration step (E0-2). - Second evaluation step (E2-2), during which the wheel units (14a, 14b, 14c, 14d) establish 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). - Second comparison step (E3-2), during which the wheel units (14a, 14b, 14c, 14d) compare the second evaluation pattern (ME2a, ME2b, ME2c, ME2d) with the second reference pattern (MR2a, MR2b, MR2c, Mr2d) to determine whether the position of the wheels (16a, 16b, 16c, 16d) has changed.

2. The detection method according to claim 1, characterized in that, The synchronization of the transmission of the series of messages with the angular position of the associated wheels (16a, 16b, 16c, 16d) is achieved by transmitting the messages sequentially with an inter-message delay determined based on the rotational speed of the wheels (16a, 16b, 16c, 16d) to cover at least one revolution of the wheels involved.

3. The detection method according to claim 2, characterized in that, The rotational speed of the wheels (16a, 16b, 16c, 16d) is provided by speed sensors (22a, 22b, 22c, 22d), which are mounted on the vehicle near the associated wheels (16a, 16b, 16c, 16d).

4. The detection method according to claim 2, characterized in that, The rotational speed of the wheels (16a, 16b, 16c, 16d) is provided by a device (15a, 15b, 15c, 15d) for measuring the angular position of the wheels (16a, 16b, 16c, 16d), which is an accelerometer (15a, 15b, 15c, 15d) mounted on the associated wheel unit (14a, 14b, 14c, 14d).

5. The detection method according to claim 1, characterized in that, The synchronization of the transmission of the series of messages with the angular position of the associated wheels (16a, 16b, 16c, 16d) is achieved by sequentially transmitting the messages based on a predetermined instantaneous angular direction of the wheels (16a, 16b, 16c, 16d), the angular direction being provided by a device (15a, 15b, 15c, 15d) for measuring the angular position of the wheels (16a, 16b, 16c, 16d).

6. The detection method according to any one of claims 1 to 5, 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 at least one wheel unit (14a, 14b, 14c, 14d) via the bidirectional radio frequency communication component (18) to merge the reference pattern and the evaluation pattern.

7. The detection method according to any one of claims 1 to 5, characterized in that, The message that enables the establishment of the reference style and the evaluation style each includes an identification reference.

8. The detection method according to claim 1, characterized in that, It includes a positioning step (E4) which is designed to determine the position of the wheels (16a, 16b, 16c, 16d) on the motor vehicle (10), and is performed 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 any one of claims 1 to 5 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 bidirectional radio frequency communication component (18), the wheel unit comprising electronic components of sensors and the wheel unit mounted on the wheels (16a, 16b, 16c, 16d) of the motor vehicle (10), the bidirectional radio frequency 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 bidirectional radio frequency communication component (18) are appropriately programmed to implement the method as described in any one of claims 1 to 9.

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