Method for identifying a pressure sensor and device for implementing the method

Abstract

The invention relates to a method for identifying a pressure sensor, in particular a pressure sensor for an electronic tire pressure monitoring system for a motor vehicle, the sensor (9, C1, C2, C3, C4) comprising at least one module for transmitting and receiving data, the method comprising: transmitting (S1) a sensor activation signal; receiving (S2) signals from at least two different sensors after the at least two different sensors have been activated; attenuating and amplifying (S3) the received signals; determining (S4) a value indicating the power of each of the received signals; identifying (S5) the spatial position of at least one sensor based on the value indicating the power of the received signals. The invention also relates to a device configured to implement the method.

Description

Technical Field

[0001] The present invention relates to the field of sensors, and in particular to a method for identifying said sensors so as to make it possible to distinguish said sensors and to locate said sensors, and to a device for implementing said method.

[0002] More specifically, the invention is advantageously applicable to pressure sensors housed in tires of motor vehicles, sensors generally associated with a computer of the motor vehicle to which said sensor sends data. Background Art

[0003] The sensor / on-board computer assembly is therefore designated by the term electronic "tire pressure monitoring system" (with the associated abbreviation "TPMS").

[0004] Each pressure sensor is conventionally equipped with a radio frequency transmitter for sending data to an onboard computer. The onboard computer receiving the data from the sensor can thus alert the user of the vehicle if one tire bursts or deflates, thereby posing a safety risk to the user.

[0005] However, the pressure sensors housed in the wheels are usually not removable, so replacing the wheel involves replacing the sensor, which is then no longer detected by the vehicle's onboard computer.

[0006] Therefore, when a tire is replaced, the sensor contained in the new tire must be paired (or associated) with the vehicle's onboard computer.

[0007] This pairing is done with the help of a dedicated learning device (usually referred to in English as a "TPMS tool"), which is configured to activate the sensors, recover and record the relevant data sent by the sensors (such as the sensor's identifier) ​​and send the relevant data to the on-board computer, so that the latter can detect and locate the sensors in the newly installed tires and can pick up the signals therefrom in order to warn the user if a pressure drop occurs in one of the tires.

[0008] However, in some vehicles, such as heavy goods vehicles or buses, the wheels are mounted in pairs at each end of an axle and the wheels are said to be paired.

[0009] In a wheel pair, the two associated sensors are sometimes very close together, making it difficult to distinguish the emissions from the sensors (both when the vehicle is stationary and during operation) without using extremely complex and expensive encoding and identification techniques.

[0010] For example, during learning, i.e., during the phase of recovering the identifiers of the sensors in order to transmit them to the on-board computer of the vehicle, the sensors are activated sequentially in a predetermined order so that the on-board computer identifies the sensors and associates them with each wheel of the vehicle. However, when an operator interrogates several sensors by means of his sensor activation device (e.g., a learning device), several sensors may be activated unintentionally at the same time. The operator may then not be able to determine whether a sensor housed in an outer wheel or a sensor housed in an inner wheel is activated.

[0011] The problem of activating several sensors simultaneously is also encountered in factories such as tire factories or motor vehicle manufacturers, where it is necessary to activate sensors in order to test them, identify them and / or pair them with the vehicle's onboard computer. However, the manufacturing lines in the factory are usually very close to each other, and the activation signal sent by the adaptation device may cause the activation of multiple sensors, so it is necessary to be able to identify or distinguish the activated sensors.

[0012] The problems disclosed above have prompted the design of a method for identifying sensors housed not only in pairs of wheels but also in individual wheels, and a device capable of implementing said method, for example a device for an electronic tire pressure monitoring system of a motor vehicle. Summary of the invention

[0013] The invention is therefore a novel method for identifying a pressure sensor, in particular a pressure sensor for an electronic tire pressure monitoring system for a motor vehicle, said sensor comprising at least one module for transmitting and receiving data,

[0014] The method comprises:

[0015] - transmit a sensor activation signal;

[0016] - receiving signals from at least two different sensors after the at least two different sensors have been activated;

[0017] -Attenuate and amplify the received signal;

[0018] - determining a value indicative of the power of a signal of each of the received signals;

[0019] - identifying a spatial position of at least one sensor based on a value indicative of a power of said received signal.

[0020] As explained above, the method according to the invention makes it possible to identify or differentiate sensors housed in a pair of wheels or in an environment containing a plurality of sensors, with the advantage of being easy to implement and applicable to a wide variety of situations.

[0021] This is because the prior attenuation before amplification makes it possible to "filter" some parasitic signals and, in particular, makes it easier to distinguish between sensors that are very close to each other.

[0022] According to one possible feature, the value indicative of the power of a signal is a gain value and / or an adaptation value of said signal.For example, each signal is characterized by a value indicating the adaptation and / or gain that each signal has undergone after its attenuation and amplification.

[0023] The value indicating the power is an indicator making it possible to characterize the signal, this value may be a gain, an adaptation value or a combination and / or function of these parameters, depending on the situation of the sensor (stationary or mobile) and its environment (parasitic signals, resonances, multiple reflections of the signal, etc.). The indication value, such as the adaptation value, depends, for example, on the settings used by the receiver, which settings are therefore an indication of the signal power.

[0024] According to another possible characteristic, the signal activating the sensor is sent at a constant power.

[0025] It is therefore not necessary to provide components for varying the transmission power of the signal activating the sensor, nor to dimension the power supply accordingly. This has the result that the design of the device implementing the method is simplified and its costs are reduced.

[0026] According to another possible feature, the received signals experience the same attenuation.

[0027] According to another possible feature, multiple signals are received from the same sensor.

[0028] Receiving multiple signals from the same sensor makes it possible to make the sensor identification process more robust by opening the possibility of applying statistical processing to the collected samples. Receiving multiple signals also makes it possible to select the signal with the greatest power (or its indication value) for each of the sensors.

[0029] Typically, the signal from the sensor is received during a predetermined period of time so that multiple signals are received from the same sensor.

[0030] Each signal sent by a sensor comprises an identifier specific to said sensor, thereby enabling the received signals to be classified. According to another possible characteristic, the signal indicating the highest value of power is selected for each of said sensors for said identification.

[0031] According to another possible feature, values ​​indicating the powers of multiple signals received from at least a first sensor and a second sensor are compared, and if all values ​​indicating the signal powers of one of the sensors are consistently smaller or larger than all values ​​indicating the signal powers of the other sensor, the spatial position of at least one sensor is identified based on the comparison of the values ​​indicating the signal powers.

[0032] According to another possible feature, the received signals and / or the values ​​indicative of the power of signals coming from the same sensor are averaged and compared with each other in order to identify the spatial position of at least one sensor.

[0033] According to another possible feature, the distribution of values ​​indicative of received signal power is studied for each sensor in order to determine the value indicative of power that is most characteristic for each sensor.

[0034] According to another possible feature, extreme values ​​of the indicated power are removed in order to determine the value of the indicated power that is most characteristic for each sensor.

[0035] According to another possible feature, the attenuation level applied to the signal is variable, for example the level varies linearly over time and / or over a predetermined period of time during which the plurality of signals are received.

[0036] The invention also relates to a device for activating a sensor, in particular a pressure sensor for an electronic tire pressure monitoring system of a motor vehicle, comprising:

[0037] - at least one sensor activation member;

[0038] - means for receiving a signal from said sensor;

[0039] - an electronic entity configured to store and / or process the information conveyed by the signals sent by said sensor;

[0040] - means for communicating with a remote electronic entity, such as an on-board computer of a motor vehicle, in order to transmit information from a received signal;

[0041] Characterized in that the receiving component comprises:

[0042] - an antenna for receiving signals from the sensor;

[0043] - an attenuator configured to attenuate the received signal,

[0044] - an amplifier configured to amplify the received attenuated signal;

[0045] Each of the signals is characterized by a value indicative of power;

[0046] The electronic entity is configured for identifying a spatial position of at least one sensor based on a value indicative of received signal power.

[0047] According to a possible feature, the sensor activation device is a learning device for an electronic tire pressure monitoring system of a motor vehicle.

[0048] According to another possible characteristic, the sensor is a pressure and / or temperature sensor housed in a tire of the motor vehicle.

[0049] According to another possible feature, each of the signals is characterized by a value indicative of an adaptation undergone by each of the signals after attenuation and amplification of each of the signals, the value indicating a power of the signal being an adapted value of the signal.

[0050] The method and the device are extremely cheap and particularly easy to implement. The method and the device also do not require any modification of the existing communication technology between the learning device and / or the activation device and the sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The invention will be better understood and other objects, details, features and advantages of the invention will become more apparent during the following description of specific embodiments of the invention given by way of illustration only and without limitation with reference to the accompanying drawings, in which:

[0052] [ Figure 1 ] is a schematic representation showing a sensor activation device according to the present invention;

[0053] [ Figure 2 ]yes Figure 1 An enlarged view of the device;

[0054] [ Figure 3 ]yes Figure 1 a highly schematic representation of the device during its use in conjunction with one of a pair of wheels;

[0055] [ Figure 4 ] is a logic diagram detailing the steps of the sensor identification method according to the present invention. DETAILED DESCRIPTION

[0056] Figure 1 is a highly schematic representation of a device 1 for activating a sensor 9, and more specifically, in this example, a learning device 1 for an electronic tire pressure monitoring system 3 for a motor vehicle 5 (the device 1 can also be designated by the terms "valve activator" or "valve forcer").

[0057] The motor vehicle 5 is equipped firstly with tires 7 in which sensors 9, such as pressure sensors, are housed, and secondly comprises an on-board computer 11 (also called electronic control unit, generally indicated by the abbreviation “ECU”).

[0058] The device 1 comprises a housing 13, for example made of plastic material, a display device 15, a keypad 17 and an antenna 19 for sending sensor activation signals, as well as an OBD (in English, "onboard diagnostic") socket. The OBD socket 21 is configured to enable the device 1 to be connected to an onboard computer 11 of a vehicle, for example, in particular by means of an OBD cable.

[0059] for Figure 2 , which is Figure 1 A magnified detail of the device.

[0060] The device 1 thus comprises:

[0061] at least one sensor activation member 31 , for example a member for generating a (continuous and / or modulated) sensor activation signal, said activation member 31 comprising an antenna 19 making it possible, in particular, to optimally propagate said generated signal to the sensor 9 ;

[0062] - receiving means 33 for receiving signals from sensors (the sensors sending signals after having been activated by said activating means 31 ), typically another antenna housed in the housing 13 and configured for example to receive signals in a frequency band between 300 MHz and 500 MHz;

[0063] an electronic entity 35 configured to store and / or process information conveyed by the signals sent by said sensor 9 (and received by means of the receiving means 33 );

[0064] Communication means 37 for communicating with the on-board computer 11 of the motor vehicle to transmit information from at least one of the sensors 9 (information received by means of a signal from said sensor 9 ).

[0065] The communication member 37 is for example an OBD module comprising a circuit 38 for managing OBD communications and the previously mentioned OBD socket 21. It should be noted that the management circuit 38 may also be integrated in the electronic entity 35. The device 1 also comprises a battery 41 configured to power the various components.

[0066] It should also be noted that the activation signal is a continuous or modulated electromagnetic signal sent by the activation member 31, having a frequency of, for example, 125 KHz.

[0067] like Figure 3 As shown, the device 1 must also be used for trucks comprising pairs of wheels, and therefore the device 1 must be able to identify or distinguish sensors contained in these tires that are placed close to each other. Figure 3In the example shown, the truck 6 includes a plurality of wheels, and the two ends of the axle 6a thereof include a pair of wheels 7a and 7b, in which sensors C1 and C2 are respectively accommodated. The truck may also include two other sensors C3 and C4, as shown in this example. Figure 3 As shown above.

[0068] More specifically, the receiving means 33 of the device 1 (means for receiving signals from the sensor) comprises at least three elements:

[0069] A receiving antenna 33a, the antenna being configured to receive a signal at a transmitting frequency of the sensor and convert the electromagnetic signal into an electrical signal;

[0070] an attenuator 33 b , for example an electronic circuit or component for reducing the amplitude of the received signal, in this case the electrical signal delivered by the antenna 33 a ;

[0071] The amplifier 33c, which is, for example, an electronic circuit or component, increases the voltage and / or strength of the electrical signal, which in the present case is the electrical signal attenuated by the attenuator 33b.

[0072] The electrical signal obtained by successive attenuation and amplification is then processed (read, decode, characterize, etc.) by an electronic entity 35 .

[0073] Furthermore, it should be noted that the attenuator 33b is adjustable, for example, with respect to levels such as 0 dB, -6 dB, -12 dB and -18 dB, or may be linearly variable between 0 dB and -18 dB.

[0074] As for the amplifier 33c, it is configured to automatically amplify the signal received as input to the required level so that the component located at the output of the amplifier (here the electronic entity 35) can process the amplified signal. This is because the electronic entity 35 (here the signal receiver) only detects and processes signals with a minimum amplitude and a signal-to-noise ratio with a certain threshold.

[0075] Thus, the amplifier 33c or third circuit implements an automatic control of the gain (also indicated by the acronym "AGC", standing for "Automatic Gain Control"), thereby providing automatic management of the amplifier amplification and avoiding output saturation and / or keeping the output level constant.

[0076] Thus, the device 1 sends an activation signal, for example in the direction of the sensors C1 and C2 housed in the pair of wheels 7 a and 7 b of the truck 6 .

[0077] The sensors C1 and C2 are activated by receiving an activation signal, and then the sensors C1 and C2 send one or more signals in response.

[0078] Disadvantageously, the activation signal sent by the device 1 may also activate one or more surrounding sensors, other sensors on the truck, or sensors housed in the tires of nearby vehicles.

[0079] Furthermore, sensors usually comprise a communication protocol which limits collisions of signals transmitted by said sensors, with the result, inter alia, that the closest sensor (the sensor which theoretically receives the activation signal first) will not necessarily transmit first.

[0080] Additionally, the sensors housed in the paired wheels are in close proximity to each other and in an environment containing obstacles that may cause multiple reflections, which may result in variations in the power of the signals sent by the sensors.

[0081] The device 1 then receives the various signals sent by the sensors C1 and C2, preferably the device 1 is configured to receive all the signals sent by the sensors during a predetermined period of time. This predetermined period of time is variable but is advantageously sized so that the device receives at least two signals from each of the sensors C1 and C2.

[0082] Attenuator 33b is configured to "strongly" attenuate the signal received via antenna 33a, the attenuation being adjusted, for example, to attenuate the signal by -12dB or -18dB (dividing the power of the received signal by 32 and 64, respectively).

[0083] This makes it possible to filter out any parasitic signals, ie signals not coming from sensors C1 and C2 or signals coming from multiple reflections (echo phenomena).

[0084] Next, the attenuator signal is amplified by the amplifier 33c.

[0085] The amplifier 33c is configured to amplify the input signal to a certain amplitude (or power) level, so the amplifier 33c will automatically amplify the signal so that the signal has the same output amplitude and / or power. The output characteristics of the signal depend in particular on the electronic components (sensors, etc.) downstream of the amplifier 33c and their configuration (i.e., the characteristics that the signal must have to be processed by the electronic components).

[0086] Thus, the signals transmitted by sensors C1 and C2, which have signals of variable power, are equally attenuated and amplified at a fixed level (eg, to obtain a given signal-to-noise ratio).

[0087] Each amplified signal can therefore be characterized by a gain G, which is proportional to the received signal power and the attenuation applied by the attenuator 33b. The value of the gain G is therefore a value representative of the signal power. This continuous attenuation and amplification makes it possible to more easily distinguish between two closely connected sensors.

[0088] This is because, if two closely connected sensors each send signals A1 and B1 with a power difference of only 20%, with A1's power = 1 and B1's power = 0.8, then without prior attenuation, amplification will produce small gain values ​​for each signal and the difference between the gains of each signal, which is not necessarily significant enough to be used to identify the relative spatial positions of the sensors relative to each other.

[0089] For example, if the power of each signal must reach a value of 1.25, the gain GA1 applied to A1 is 1.25, while the gain GB1 applied to B1 is approximately 1.56; however, if each signal undergoes a prior attenuation of -12 dB, the powers of the attenuated signals A1 and B1 are approximately 0.0625 and 0.05, respectively, and their gains are 20 and 25, respectively. It is therefore found that a strong attenuation before amplification is beneficial for identifying the sensor, based on the fact that the power of the signal sent by the sensor is proportional to its distance, and the value of the signal gain makes it possible to determine the nearest sensor (or the farthest sensor).

[0090] It should be noted that in the following examples, the value representing the signal power is a gain value applied to the signal, but this could be another characteristic quantity or a function depending on several parameters (eg attenuation, gain, etc.).

[0091] Therefore, the identification method used by the device 1 (more specifically, Figure 4 As shown) at least includes the following steps:

[0092] Transmits S1 signal to activate the sensor;

[0093] receiving S2 signals from the at least two different sensors after the at least two different sensors have been activated;

[0094] attenuating and amplifying S3 the received signals from the two sensors;

[0095] - for each signal received, determining a value indicative of the signal power (S4), for example a gain value G;

[0096] - identifying S5 the spatial position of at least one sensor based on the value indicative of the power of said received signal.

[0097] It should be noted that:

[0098] The signal activating the sensor is preferably sent at a constant power and / or has a narrow emission cone;

[0099] The received signal experiences the same attenuation.

[0100] Furthermore, the electronic entity 35 is configured for managing the reception duration in order to receive a plurality of signals from the same sensor.

[0101] Furthermore, since each signal sent by a sensor comprises an identifier specific to said sensor, the electronic entity 35 can classify the received signals according to their origin, i.e. from the sensor that sent them. Receiving several signals from the same sensor can, for example, make it possible to select the signal with the greatest gain value G (or value indicating power) in order to subsequently compare and identify the relative spatial position between two sensors.

[0102] Thus, while receiving said signals, the electronic entity 35 compares in pairs the values ​​indicating the power of the received signals and makes it possible to check that the values ​​indicating the power of the signal sent by a sensor are always less or greater than the signals sent by the other sensors. In this case, the relative spatial position of at least one sensor sending the signal is identified.

[0103] This complementary operation increases the chances of correctly identifying the spatial location of the sensor.

[0104] However, in order to further improve the identification of the sensors, it is possible to study, for example, the distribution of values ​​indicative of the power of the received signals by the sensors in order to determine the power value most likely indicative of the signal of each sensor.

[0105] The values ​​of the signal of the sensor are for example classified in intervals of values, which are also specified by mathematical terms class, i.e. extreme values ​​making it possible to define groups of value distributions. It should be noted that it is possible to define groups with or without the same amplitude (amplitude is the interval of values ​​defining each group).

[0106] Next, the number of values ​​in each class is determined, and the group containing the largest number is selected (the latter is also designated by the term "modal class").

[0107] The interval including the most values ​​is then considered the most probable interval, and it is possible to take the average of the values ​​contained in this interval to determine the value indicating the signal power that is most characteristic for each sensor, the characteristic values ​​of each sensor being then compared with each other to determine the sensor that is closest to (or farthest from) the receiving member 33.

[0108] It should be noted that, whatever the method used, this can be generalized to n sensors, comparing and classifying the values ​​indicative of power, thereby making it possible to determine the relative spatial positions of the sensors from which the signals were received with respect to each other.

[0109] In an embodiment not shown, the attenuation level applied to the signal generated by the attenuator 33b varies linearly over time, for example. In this case, the value indicating the signal power is actually a value as a function of gain and attenuation, such as a signal adaptation value.

[0110] Furthermore, the linear variation in attenuation makes it possible to additionally reveal transient phenomena that may affect the received signal and to eliminate these phenomena in order to improve the identification of the sensor.

Claims

1. A method for identifying a pressure sensor of an electronic tire pressure monitoring system of a motor vehicle, the pressure sensor (9, C1, C2, C3, C4) comprising at least one module for transmitting and receiving data, The method comprises: - transmitting (S1) a sensor activation signal; - receiving (S2) signals from the at least two different sensors after the at least two different sensors have been activated; - attenuating and amplifying the received signal (S3); - determining (S4) a value indicative of the power of said signal for each of said signals received; - identifying (S5) a spatial position of at least one sensor based on said value indicative of said power of said received signal, The characteristic is that the signal is received only within a predetermined period of time and is attenuated and amplified with the same parameters.

2. The method according to claim 1, characterized in that The value indicative of the power of the signal is a gain value (G) and / or an adaptation value of the signal.

3. The method according to claim 1, characterized in that The signal activating the pressure sensor (9, C1, C2, C3, C4) is sent at a constant power.

4. The method according to claim 3, characterized in that The signals experience the same attenuation.

5. The method according to claim 1, characterized in that Multiple signals are received from the same pressure sensor (9, C1, C2, C3, C4).

6. The method according to claim 5, characterized in that The signal for which the value indicative of power is highest is selected for each of the pressure sensors (9, C1, C2, C3, C4) used for the identification.

7. The method according to claim 6, characterized in that comparing said values ​​indicative of said power of said plurality of signals received from at least a first pressure sensor (C1) and a second pressure sensor (C2), If all the values ​​of the power of the signal indicating one of the first pressure sensor (C1) and the second pressure sensor (C2) are always smaller than or larger than all the values ​​of the power of the signal indicating the other of the second pressure sensor (C2) and the first pressure sensor (C1), respectively, then the spatial position of at least one of the first pressure sensor (C1) and the second pressure sensor (C2) is identified.

8. The method of claim 1, wherein the level of attenuation applied to the signal is variable.

9. A device (1) for activating a pressure sensor (9, C1, C2, C3, C4) of an electronic tire pressure monitoring system on a motor vehicle, the device comprising: at least one sensor activation member (31); a receiving member (33) for receiving a signal from the sensor only within a predetermined period of time; an electronic entity (35) configured to store and / or process information conveyed by said signal sent by said sensor; communication means (37) for communicating with a remote electronic entity in order to transmit said information from said received signal; Characterized in that the receiving member (33) is configured to implement the method according to claim 1 and comprises: An antenna (33a) for receiving the signal from the pressure sensor (9, C1, C2, C3, C4); an attenuator (33b) configured to attenuate the received signal by the same parameter, an amplifier (33c) configured to amplify the received attenuated signal with the same parameters; Each of the signals is characterized by a value (G) indicative of power; The electronic entity (35) is configured to identify the spatial position of at least one pressure sensor (9, C1, C2, C3, C4) based on the value indicative of the power of the received signal.

10. The device according to claim 9, characterized in that Each of the signals is characterized by a value indicative of adaptation experienced by each of the signals after the attenuation and amplification of each of the signals, the value indicative of the power of the signal being an adaptation value for the signal.

Images