System for wireless measurement of an aircraft tyre pressure

Abstract

A system for the wireless measurement of the pressure of a tyre (111, 112, 121, 122, 123, 124) of an aircraft (100) comprises: - N pressure sensors intended to be placed on a tyre of the aircraft, N being an integer greater than or equal to 1; - an interrogation module (140) for interrogating the N wireless pressure sensors; and - M radiating antennas (151, 152, 153, 154, 155, 156), M being an integer greater than or equal to 1, characterized in that the N pressure sensors are surface wave sensors each comprising a radiating cell and a surface wave pressure measurement cell, the N radiating cells and the M radiating antennas being configured to emit at frequencies between 2.4 GHz and 2.5 GHz and the M radiating antennas being configured to transmit electrical signals between the interrogation module and the N pressure sensors.

Description

[0001] Description

[0002] Title of the invention: Wireless pressure measurement system in an aircraft tire

[0003] Technical Field

[0004] The present invention relates to the general field of pressure measurement systems in aircraft tires, in particular to a wireless pressure measurement system.

[0005] Previous technique

[0006] Aircraft tire pressure monitoring systems typically use sensors mounted on the wheel rims that communicate via electrical wires running through the axle and along the landing gear. A rotary joint system allows for the exchange of data and the power required for the measurement system's operation between the avionics, acting as an internal or external control unit, and the pressure sensors.

[0007] To eliminate this rotating joint, wireless pressure sensors with a range of a few meters are used. These reduce the overall weight of the system, simplify installation, and lower maintenance costs. These sensors typically transmit their measurements to the avionics via Bluetooth Low Energy (BLE).

[0008] These wireless pressure sensors operating via BLE require a battery to perform their measurement and transmission functions.

[0009] However, this battery has a limited lifespan and / or a mass that can be problematic if one seeks to increase its lifespan.

[0010] Furthermore, due to the high temperatures at the aircraft tires, and therefore at the pressure sensor, a heat shield is necessary to lower the temperature to levels acceptable to the sensors. This heat shield adds extra mass and volume. Finally, the use of BLE technology requires the implementation of complex cybersecurity measures that must be maintained throughout the sensor's lifespan, thus increasing the sensor's production and maintenance costs.

[0011] Therefore, it would be desirable to have a new system for measuring pressure in aircraft tires including wireless pressure sensors and making it possible to do without the use of a battery, thermal shield and complex cyber-security means for the operation of the sensors.

[0012] Description of the invention

[0013] The present invention therefore relates to a wireless pressure measurement system in an aircraft tire comprising:

[0014] - N pressure sensors intended to be placed on an aircraft tire, N being an integer greater than or equal to 1;

[0015] - a module for querying the N wireless pressure sensors; and

[0016] - M radiating antennas, M being an integer greater than or equal to 1, characterized in that the N pressure sensors are surface wave sensors each comprising a radiating cell and a surface wave pressure measuring cell, the N radiating cells and the M radiating antennas being configured to emit at frequencies within a frequency band and the M radiating antennas being configured to transmit electrical signals between the interrogation module and the N pressure sensors.

[0017] Thanks to the invention and surface wave measuring cells, pressure sensors do not require a power source, i.e., a battery, to operate. These measuring cells use the principle of transforming an initial electrical signal into a mechanical wave propagating across their surface. The mechanical wave thus generated is then transformed back into a second electrical signal, and the difference between the two electrical signals determines the pressure measurement, as the generated mechanical wave is affected by its environment.

[0018] The emission frequency band of the radiating antennas is, for example, the [2.4 GHz; 2.5 GHz] band, or the [4.2 GHz; 4.4 GHz] band.

[0019] According to one embodiment of the invention, N is equal to M, and each radiating antenna is configured to communicate with a radiating cell of a single pressure sensor from the N pressure sensors at the same given frequency. The given frequency is therefore the same for all radiating antennas and is, for example, 2.4 GHz.

[0020] There are as many radiating antennas as there are pressure sensors, and each antenna is positioned to communicate with only one pressure sensor. Since the antennas are all configured to communicate with the sensors at the same frequency, they are easily interchangeable and replaceable.

[0021] Furthermore, because they are configured to communicate with the 2.4 GHz sensors, the range of the radiating antennas is limited to approximately 1 meter. This embodiment is therefore suitable for small aircraft with a relatively small number of wheels and tires, typically two per landing gear.

[0022] According to another embodiment of the invention, N is strictly greater than M, and at least one of the M radiating antennas is configured to communicate with at least two radiating cells of two pressure sensors of the N pressure sensors at different frequencies.

[0023] In this embodiment, a radiating antenna of the M radiating antennas thus has a wider transmit and receive beam than one of the M radiating antennas of the previously described embodiment; and it uses specific and distinct frequencies to separately query the sensors it is responsible for. For example, a radiating antenna could be dedicated to two sensors and thus communicate with these two sensors at two distinct frequencies. For example, the communication frequencies are in a frequency band from 2400 MHz to 2445 MHz for a radiating antenna communicating with one sensor, or in a frequency band from 2455 MHz to 2500 MHz for a radiating antenna communicating with several sensors.

[0024] This embodiment makes it possible to reduce the number of radiating antennas, which simplifies their installation, as well as their maintenance and the number of wired links or cables that can connect the antennas to the interrogation module or present in a box if antennas are grouped in the same box.

[0025] According to a particular feature of the invention, at least two radiating antennas of the M radiating antennas are grouped together in a single housing. This optimizes the number of housings and thus reduces the overall size of the M radiating antennas.

[0026] According to another particular feature of the invention, the measurement system includes a wired link connecting the interrogation module to the M radiating antennas.

[0027] According to another particular feature of the invention, the measurement system includes at least one relay device configured to communicate in a wired manner with the interrogation module and with the M radiating antennas, the relay device being configured to transmit data between the M radiating antennas and the interrogation module.

[0028] This reduces the amount of cabling along the landing gear, because the relay system allows secondary interrogation modules to be placed as close as possible to the wheels, for example, on the wheel axles, which are connected to radiating antennas; then a single cable connects the secondary interrogation module or relay system to the interrogation module. This feature is complex to implement, but is advantageous for large aircraft because it reduces the amount of cabling.

[0029] According to another particular feature of the invention, the measurement system includes a switch configured to activate or deactivate a radiating antenna. The switch allows a radiating antenna to be activated or deactivated according to the instructions of the interrogation module, for example, in order to communicate with, and thus obtain a pressure measurement from, a specific pressure sensor.

[0030] The switch can be configured to enable or disable a single radiating antenna, or multiple radiating antennas.

[0031] It can also be configured to activate or deactivate all radiating antennas present in the same box.

[0032] The system may also include a switch for several wheels, for example, a switch per landing gear, and therefore the switch can also be configured to activate or not radiating antennas present in different housings but on the same landing gear.

[0033] According to another particular feature of the invention, the N pressure sensors each comprise a surface wave temperature measurement cell. Indeed, since the mechanical wave generated on the surface of the surface wave pressure measurement cell is affected by its environment, it is therefore influenced by the surrounding temperature. The surface wave temperature measurement cell thus allows a temperature-dependent correction factor to be applied to the pressure measurement of the surface wave pressure measurement cell.

[0034] Another object of the invention is an aircraft comprising a plurality of wheels equipped with a tire and a pressure measurement system according to the invention, in which N is equal to the number of wheels present in the aircraft.

[0035] Brief description of the drawings

[0036] Other features and advantages of the present invention will become apparent from the description given below, with reference to the accompanying drawings which illustrate examples of embodiments without being limiting in any way. [Fig. 1] Figure 1 represents, schematically and partially, an aircraft comprising a system for measuring pressure in an aircraft tire according to an embodiment of the invention.

[0037] [Fig. 2] Figure 2 schematically and partially represents an aircraft comprising a pressure measurement system in an aircraft tire according to another embodiment of the invention.

[0038] [Fig. 3] Figure 3 schematically and partially represents an aircraft comprising a pressure measurement system in an aircraft tire according to another embodiment of the invention.

[0039] [Fig. 4] Figure 4 schematically and partially represents an aircraft comprising a pressure measurement system in an aircraft tire according to another embodiment of the invention.

[0040] Description of the implementation methods

[0041] Figure 1 represents, schematically and partially, an aircraft 100 comprising a tire pressure measurement system 111, 112, 121, 122, 123, 124 according to a first embodiment of the invention.

[0042] The pressure measurement system includes an interrogation module 140, radiating antennas 151, 152, 153, 154, 155, 156, and surface wave pressure sensors. More specifically, in Figure 1, three axles or landing gear 110, 120, 130, each carrying two tires 111, 112; 121, 122; 123, 124, are shown, and a surface wave pressure sensor is present on each of the tires 111, 112, 121, 122, 123, 124. In addition, each axle 110, 120, 130 supports two radiating antennas 151, 153; 153, 154; 155, 156. Each pressure sensor comprises a radiating cell and a surface wave pressure measurement cell. Each radiating antenna 151, 152, 153, 154, 155, 156 is a directional antenna, as it is configured to communicate with a single pressure sensor, specifically with the pressure sensor's radiating cell, at the same frequency, for example 2.4 GHz.Thus, the transmission / reception beams or the range of the radiating antennas 151, 152, 153, 154, 155, 156 are represented by the beams 1511, 1521, 1531, 1541, 1551, 1561 which are visible only by one sensor among the six sensors shown in Figure 1.

[0043] The interrogation module 140 is configured to query the sensors, that is, to request them to perform a pressure measurement in the tire associated with the sensor. This measurement request is transmitted to the sensor via the radiating antenna associated with the pressure sensor. The radiating antennas 151, 152, 153, 154, 155, and 156 communicate with the interrogation module 140 via wired connections.

[0044] Surface wave measuring cells are known and are described for example in document EP 4 186792. They include a surface made of piezoelectric material and a device called an interdigitated comb engraved on their surface.

[0045] The measuring cells receive an electrical signal, transmitted by the radiating cell and the radiating antenna associated with the sensor, from the interrogation module 140. They convert this signal into a mechanical wave propagating across their piezoelectric material surface via their interdigitated comb. The mechanical wave generated on their surface is affected by its environment, such as the surrounding temperature and pressure, and is then converted back into an electrical signal. It is the change in the electrical signals that allows for a measurement, in this case, of pressure and temperature. This change in the electrical signals is, for example, a time delay or a difference in resonant frequency between the two signals.

[0046] Figure 2 represents, schematically and partially, an aircraft 200 comprising a tire pressure measurement system 211, 212, 213 according to a second embodiment of the invention.

[0047] Compared to the first embodiment described with reference to Figure 1, in this embodiment, the radiating antennas are grouped in a single housing. Thus, in this second embodiment, the housing 251 comprises three radiating antennas configured to communicate with the interrogation module 240 and with the pressure sensors, in particular, the radiating cells of the pressure sensors present on the tires 211, 212, 213.

[0048] In this second embodiment, the housing 251 comprises three radiating antennas, each configured to communicate at 2.4 GHz with a single sensor. One of the antennas can therefore communicate with the sensor on the tire 211 with the range represented by the transmit / receive beam 2511; another antenna can communicate with the sensor on the tire 212 with the range represented by the transmit / receive beam 2512; and finally, the last antenna can communicate with the sensor on the tire 212 with the range represented by the transmit / receive beam 2513.

[0049] In this second embodiment, it is possible to have a single unit containing all the radiating antennas communicating with all the sensors present on the same landing gear; or to have two units sharing the radiating antennas, one of the units (and therefore the associated antennas) being dedicated to the sensors present on the inner tires of the landing gear, and the other unit (and therefore the associated radiating antennas) being dedicated to the sensors present on the outer tires of the landing gear.

[0050] Figure 3 represents, schematically and partially, an aircraft 300 comprising a system for measuring pressure in the tires 311, 312, 321, 322, 331, 332 mounted on the axles or landing gear 310, 320, 330 according to a third embodiment of the invention.

[0051] In this third embodiment, compared to the first embodiment described with reference to Figure 1, the measurement system comprises a single radiating antenna 351, 352, 353 for each axle 310, 320, 330 of the aircraft 300. Thus, the radiating antenna 351 is configured to communicate with the pressure sensors on the tires 311, 312 via its transmit and receive range 3511. The radiating antenna 352 is configured to communicate with the pressure sensors on the tires 321, 322 via its transmit and receive range 3521. The radiating antenna 353 is configured to communicate with the pressure sensors on the tires 331, 332 via its transmit and receive range 3531.The three radiating antennas 351, 352, and 353 are configured to transmit in a frequency band, for example, between 2.4 GHz and 2.5 GHz. Specifically, they are configured to transmit at two different frequencies between 2.4 GHz and 2.5 GHz to communicate with only one pressure sensor at a time. The frequency band could also be between 4.2 GHz and 4.4 GHz.

[0052] In this third embodiment, the interrogation module 340 can request a pressure measurement from a particular sensor via one of the radiating antennas 351, 352, 353 by indicating a transmission and reception frequency to the antenna so that it can address itself to the sensor chosen by the interrogation module 340 (or good sensor).

[0053] Figure 4 schematically and partially represents an aircraft 400 comprising a tire pressure measurement system 411, 412, 413 according to a fourth embodiment of the invention.

[0054] Compared to the second embodiment described with reference to Figure 2, in this fourth embodiment, the radiating antennas are still grouped in a single housing 451, but a secondary relay or interrogation module 441 is present in the pressure measurement system. The radiating antennas within the housing 451 are each dedicated to a single pressure sensor, and their range 4511, 4512, 4513 is therefore visible from only one pressure sensor.

[0055] The interrogation module 440 transmits its measurement requests to the pressure sensors via the radiating antennas through the relay device 441. This reduces the length and mass of cables or wired connections at the aircraft landing gear 400, since the relay device 441 can be positioned as close as possible to the radiating antennas. For example, the aircraft 400 could have one relay device 441 per landing gear.

[0056] Regardless of the embodiment, the polling module can be configured to transmit the transmit and receive frequency of the radiating antennas when it sends its pressure measurement request to the sensors via the radiating antennas. This is particularly advantageous when a radiating antenna is configured to communicate with multiple pressure sensors, as it allows the polling module to specify which sensor it wishes to poll so that the radiating antenna transmits this request to the sensor chosen by the polling module (or correct sensor) and then receives the electrical signal representing the pressure measurement of that sensor.

[0057] Regardless of the implementation method, a wired connection may be present between the interrogation module and the radiating antennas.

[0058] Regardless of the specific embodiment, the measurement system may also include a switch located near the radiating antennas and / or the housings containing the radiating antennas. The switch is then configured to address each radiating antenna sequentially. In other words, the switch enables or disables a radiating antenna and thus its transmission / reception of data to or from a pressure sensor. In this case, the radiating antennas controlled by this switch may have overlapping ranges, and / or communicate at different frequencies between 2.4 GHz and 2.5 GHz with their associated sensor(s), and / or communicate at 2.4 GHz with their associated sensor(s).

Claims

Demands

1. Wireless tire pressure measurement system for aircraft (100, 200, 300, 400) tires (111, 112, 121, 122, 123, 124, 211, 212, 213, 311, 312, 321, 322, 331, 332, 411, 412, 413) comprising: - N pressure sensors, each pressure sensor being intended to be placed on a tire of the aircraft, N being an integer greater than or equal to 1; - a interrogation module (140, 240, 340, 440) for the N wireless pressure sensors; and - M radiating antennas (151, 152, 153, 154, 155, 156, 351, 352, 353), M being an integer greater than or equal to 1, characterized in that the N pressure sensors are surface wave sensors each comprising a radiating cell and a surface wave pressure measuring cell, the N radiating cells and the M radiating antennas being configured to emit at frequencies within a frequency band and the M radiating antennas being configured to transmit electrical signals between the interrogation module and the N pressure sensors, and in that at least two radiating antennas of the M radiating antennas are grouped in the same housing (251, 451).

2. Pressure measurement system according to claim 1, wherein N is equal to M and each radiating antenna (151, 152, 153, 154, 155, 156) is configured to communicate with a radiating cell of a single pressure sensor of the N pressure sensors at the same given frequency.

3. Pressure measurement system according to claim 1, wherein N is strictly greater than M, and at least one of the M radiating antennas (351, 352, 353) is configured to communicate with at least two radiating cells of two pressure sensors of the N pressure sensors at different frequencies.

4. A pressure measurement system according to any one of claims 1 to 3, comprising a wired connection linking the interrogation module to the M radiating antennas.

5. A pressure measurement system according to any one of claims 1 to 4, comprising at least one relay device (441) configured to communicate via a wired connection with the interrogation module and with the M radiating antennas, the relay device being configured to transmit data between the M radiating antennas and the interrogation module.

6. A pressure measurement system according to any one of claims 1 to 5, comprising a switch configured to activate or deactivate one of the M radiating antennas.

7. Pressure measurement system according to any one of claims 1 to 6, wherein the N pressure sensors each comprise a surface wave temperature measurement cell.

8. Aircraft comprising a plurality of wheels equipped with a tire and a pressure measurement system according to any one of claims 1 to 7, wherein N is equal to the number of wheels present in the aircraft.

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