Aircraft systems and methods

Abstract

The present invention relates to aircraft systems and methods. The present invention provides a computer-implemented method of tire maintenance. The method includes receiving data of a plurality of tire gas pressure measurements, each measurement having an associated time; analyzing the received data to determine maintenance information, wherein the maintenance information includes at least one of the following: an inflation event, a maximum pressure, a minimum pressure, and a tire replacement event; and providing an indication based on the determined maintenance information.

Description

Technical Field

[0001] This invention relates to a method for tire maintenance using historical data and a tire monitoring device and system for implementing these methods. Background Technology

[0002] Tire pressure monitoring is a critical part of aircraft maintenance. Underinflated tires are more likely to burst during takeoff and / or landing, and a tire blowout can cause serious damage to the surrounding aircraft structure. Therefore, regular tire pressure checks are mandatory for commercial aircraft.

[0003] Current methods for checking tire pressure include manual methods (using a pressure gauge to measure each individual tire) and automatic methods (interrogating the pressure sensor attached to each wheel to measure the relevant tire pressure). Regardless of whether the pressure check is manual or automatic, tire pressure maintenance decisions are based on readings of all tires taken in a single measurement session. For example, with manual measurement, the pressure of each tire is measured and recorded sequentially. With automatic measurement, the pressure of each tire can be measured essentially simultaneously or sequentially.

[0004] To provide reliable results, tire pressure should be measured when the gas in the tires is at ambient temperature. If the tires are above ambient temperature, this will increase the measured pressure, potentially making it impossible to correctly identify tires requiring maintenance. If tire pressure is measured when the tires are "hot" or above ambient temperature, the additional gas temperature above ambient temperature will mean higher pressure, making it impossible to detect underinflation. The gas in the tires can take a long time to reach ambient temperature because it is heated by nearby braking system components, such as brake discs, which radiate heat even when the aircraft is stationary. Therefore, Airbus requires the aircraft to be stationary for at least three hours before taking tire pressure measurements.

[0005] The three-hour requirement imposes significant operational constraints, especially with short turnaround times, which may limit opportunities to perform tire pressure measurements. For example, it might only be possible if the aircraft has been idle overnight and stationary for the required amount of time.

[0006] Automatic pressure sensing devices fixed to aircraft wheels may include temperature sensors, but these sensors do not directly measure gas temperature. The nature of being fixed to the wheels means that while pressure is directly sensed, temperature is measured indirectly through the temperature sensor within the sensing device. The temperature sensor is indirectly coupled to the gas in the tire, therefore it cannot be assumed that the measured temperature is the same as the gas temperature in the tire. Furthermore, the relationship between gas temperature and the temperature sensor is complex, influenced by factors such as the time it takes for heat to transfer through the wheels and external sources, such as cooling brake discs and current weather conditions.

[0007] We hope to improve aircraft tire maintenance. Summary of the Invention

[0008] According to a first aspect of the present invention, a computer-implemented method for tire maintenance is provided. The method includes: receiving data of a plurality of tire gas pressure measurements, each measurement having an associated time; analyzing the received data to determine maintenance information, wherein the maintenance information includes at least one of: inflation events, maximum pressure, minimum pressure, and tire replacement events; and providing instructions based on the determined maintenance information.

[0009] Maintenance information may include minimum pressure, and therefore analysis may include: determining the minimum pressure between two consecutive inflation events; and determining that the minimum pressure is less than a predetermined threshold. The time period during which the pressure is less than the predetermined threshold can be determined.

[0010] Maintenance information may include maximum pressure, and therefore analysis may include: determining the maximum pressure between two consecutive inflation events; and determining that the maximum pressure is greater than a predetermined threshold.

[0011] Maintenance information can include inflation events, and therefore analysis can include identifying inflation events by recognizing a positive pressure increase gradient greater than 1 psi per minute. The inflation frequency or the interval between successive inflation events can then be determined.

[0012] The analysis may include determining the frequency of tire replacements or the intervals between consecutive tire replacements.

[0013] It can receive data on the number of tire retreads and use that data to determine whether there is a correlation between the number of retreads and inflation frequency, the interval between consecutive inflation events, the frequency of tire replacement, or the interval between consecutive tire replacements.

[0014] The received data may relate to at least two tires on the same aircraft, and therefore the analysis may include comparing specific maintenance information of at least two tires. For example, the analysis of the data may include: determining the deflation rate of at least two tires; and determining that the deflation rate of a first tire of the at least two tires is greater than the deflation rate of another tire of the at least two tires.

[0015] According to a second aspect of the present invention, a computer-implemented method for tire maintenance is provided. The method includes: receiving data of a plurality of tire gas pressure measurements, each measurement having an associated time; analyzing the received data to determine a plurality of inflation events; determining a minimum pressure between two consecutive inflation events; determining maintenance information based on a comparison of the minimum pressure with a predetermined threshold; and providing instructions based on the maintenance information.

[0016] The first or second approach may include standardizing pressure data to express pressure at a predetermined reference temperature.

[0017] The first or second approach may include scheduling maintenance actions based on the determined maintenance information.

[0018] In the method of the first or second aspect, the received data may include data having unique tire identifiers associated with multiple tire gas pressure measurements. Therefore, the method may include one or both of the following: using a database to determine that the unique tire identifier corresponds to a safe-to-use tire; and updating the database based on maintenance information and the tire's unique identifier.

[0019] According to a third aspect of the invention, a processing system is provided, which is configured to implement the method of the first aspect or the second aspect.

[0020] According to a fourth aspect of the invention, a computer-readable medium is provided, comprising computer-executable instructions that, when executed by a processing system, instruct the processing system to perform the method of the first aspect or the second aspect.

[0021] Other features and advantages of the invention will become apparent from the following description of preferred embodiments of the invention, which are given by way of example only with reference to the accompanying drawings. Attached Figure Description

[0022] Figure 1 A schematic diagram of a tire monitoring device is shown.

[0023] Figure 2 A schematic diagram of the aircraft is shown.

[0024] Figure 3 This is a flowchart illustrating an example method for a tire monitoring device to store the history of temperature and pressure measurements.

[0025] Figure 4 The simulation shows the changes in tire pressure and tire gas temperature data over time during aircraft operation.

[0026] Figure 5This is a flowchart of an example method for tire maintenance using historical data.

[0027] Figure 6 A trend line depicting the variation of example pressure over time is shown.

[0028] Figure 7 Example standardized pressure data from the first tire monitoring device over a three-year period are depicted.

[0029] Figure 8 Example standardized pressure data from the second tire monitoring device were depicted over the same three-year time period.

[0030] Figure 9 It is a flowchart that uses historical data to identify maintenance information or maintenance trends.

[0031] Figure 10 A schematic diagram of a system in which the method can be implemented is shown.

[0032] Figures 11 to 14 Examples of historical tire pressure data over time that indicate a tire is unsafe and should no longer be used are depicted. Detailed Implementation

[0033] It has been found that if historical records of tire pressure and temperature measurements are retained, the historical data can be used to improve the reliability of tire pressure measurements and improve tire maintenance.

[0034] With the advent of automated electronic tire monitoring devices (ATMs) mounted on aircraft wheels, tire pressure can be measured periodically to obtain historical pressure data without the need for operators to input and store data via associated measurement timestamps. When the tire monitoring device also includes a temperature sensor, temperature data can also be stored along with pressure data. Therefore, historical records of pressure / temperature pairs with associated timestamps can be built over time.

[0035] Both pressure and temperature vary depending on the aircraft's operation, including flight length, turnaround time, ambient temperature at the destination, and weather conditions. As mentioned above, temperature sensors may not directly measure gas temperature, and therefore cannot be assumed that the temperature measured by the temperature sensor is an accurate measurement of the actual gas temperature inside the tire. The inventors have recognized that once both pressure and temperature are stable, even indirect temperature measurements can be assumed to be accurate, as will now be explained in more detail.

[0036] A stable pressure point emerges when the temperature of the gas inside the tire changes by a relatively small amount, typically close to ambient temperature. This means that heat sources, such as hot brake discs, have cooled and the gas temperature has stabilized. (Over short periods, such as 10, 20, 30 minutes, or similar, the measured pressure changes are most strongly dependent on temperature). While stable pressure usually occurs when the gas temperature is close to ambient temperature, this is not always the case; wind chill and heating from direct sunlight can affect gas temperature. Therefore, the actual gas temperature remains uncertain. It is recognized that if the temperature measured by a temperature sensor is also stable, then that measurement is a more accurate indication of the gas temperature, even for indirect temperature measurements. Tire monitoring devices containing temperature sensors are fixed to the same wheel as the tire and are therefore exposed to roughly the same ambient temperature and external heating or cooling effects as the tire. The temperature of the sensing device stabilizes, just as the gas temperature inside the tire stabilizes. Although measuring temperature using a temperature sensor is an indirect measurement, it is an approximation of the gas temperature at these stable points.

[0037] Stabilization points can be identified from time series of pressure and temperature measurements—data from time series in which both pressure and temperature change slightly over a predetermined period. For example, stabilization points can be identified or determined when both pressure and temperature change by less than 5%, 4%, 3%, 2%, or 1% over time periods such as 10, 20, or 30 minutes. These points can then serve as accurate measurements of pressure and gas temperature within the tire and be used in various ways for tire maintenance and / or monitoring. Temperature changes are preferably measured in Kelvin because, although the changes are relative (and therefore dimensionless), the different zero points on the Celsius and Fahrenheit scales can exaggerate sensitivity to changes near zero. Particularly within the Celsius scale, the zero point is close to the ambient temperature at some destinations.

[0038] In other examples, a steady point can be identified from absolute changes. A steady pressure can be a pressure that changes by less than 5 psi, less than 3 psi, or less than 1 psi over a time period of 10, 20, or 30 minutes. A steady temperature can be a temperature that changes by less than 5°C, less than 3°C, or less than 1°C over a time period of 10, 20, or 30 minutes.

[0039] In another example, a stability point can be identified by substantially similar rates of pressure change and substantially similar rates of temperature change at the beginning and end of a predetermined time period. This time period could be 5 minutes, 10 minutes, 20 minutes, or 30 minutes. The substantially similar rates of change in temperature and pressure indicate that the temperature measurement accurately tracks the pressure measurement, so that even if the absolute values ​​change significantly over a period of time, the temperature can still be considered an accurate representation of the gas temperature within the tire. More specifically, a time period can be identified as containing a stability point if the pressure gradient with respect to time is less than 1%, less than 3%, or less than 5% at the beginning and end of the predetermined time period; and if the temperature gradient with respect to time is less than 1%, less than 3%, or less than 5% at the beginning and end of the predetermined time period.

[0040] This is a characteristic of a stationary point where the measured quantity does not change significantly over time, thus eliminating the need for high-frequency measurements; a stationary point is a point where the change is minimal over a few minutes. However, there are maximum limitations to the time intervals used to assess stationary points. If the intervals between measurements are too long, it may be difficult to identify stationary points due to variations in ambient temperature, or stationary points may be incorrectly identified despite temperature fluctuations. For example, a two-hour interval between measurements may be long enough for sufficient variation in ambient temperature during the day to make it impossible to identify a stationary point. Similarly, a two-hour interval between measurements may be sufficient for short flight cycles to cause measurements to appear stationary when there are actually significant changes. In both cases, shorter intervals between measurements, such as every 10 minutes, every 20 minutes, or every 30 minutes, allow for more reliable determination of stationary points.

[0041] Once a stable set of pressure and temperature points has been identified, pressure trends in the tire can be identified and used for tire monitoring and / or maintenance.

[0042] Pressure and temperature data can be stored in the memory of the individual sensors themselves or elsewhere, such as within the aircraft itself or in a central system located far from the aircraft, such as in the cockpit system or maintenance facilities. While the amount of memory that can be integrated into the sensors themselves may be limited, thus limiting the amount of data that can be retained, transmitting data and storing it elsewhere can preserve a long history of measurement data. For example, a central system can effectively store pressure and temperature pairs of data indefinitely, thus retaining measurement data throughout the entire lifespan of the tire. Such a system can also retain data that persists even when the tire undergoes physical changes, such as during retreading (also known as modification).

[0043] As another benefit, by using automated sensors for measurement, data can be obtained automatically without the need for additional work by maintenance personnel.

[0044] The measurement data can initially be stored in the tire monitoring device itself, in a central system that is part of the aircraft, or in both. When tire pressure is measured, such as during a forced tire pressure check, the measurement data can be transmitted to another device or system.

[0045] Once determined, stable pressure measurements can be converted or normalized to pressures at the same predetermined temperature, allowing for direct comparison. For example, pressure can be converted to normalized pressure at 15°C. This can be done in several ways. One approach is to use known relationships about how much pressure changes with temperature, such as a 10°C change in temperature resulting in a 3.7% change in pressure. Another approach is to apply the ideal gas law. Using known relationships may be computationally simpler, while applying the ideal gas law may be more accurate. In both cases, some assumptions are made about the behavior of the tire and its internal gases. These assumptions might include that the gas is an ideal gas and that the tire's volume does not change. Aircraft tires are filled with nitrogen, which can be considered an ideal gas within the operating pressure and temperature range experienced by the aircraft tire. Aircraft tires are inflated to relatively high pressures, typically 200 psi (1379 kPa / 13.79 bar), and the tire's structure implies minimal volume change within the tire's operating pressure range.

[0046] Other assumptions or variables can be considered, such as whether the tires are loaded or unloaded (e.g., measurements taken during flight will be unloaded). This can depend on the specific aircraft and tire configuration. For example, it has been suggested that the pressure difference measured between unloaded and loaded tires is 4%, while other tests on the Airbus A380 have shown little measurable change in tire pressure between loaded and unloaded states. Therefore, the effect of tire load on pressure can depend on a specific aircraft model or a specific combination, such as a specific combination of two or more of the aircraft model, wheel configuration, and tire model. If tire load is considered to adjust pressure measurements, then periods of tire unloading can be identified from trends in historical data, and measurements can be adjusted according to the tire load state. For example, a relatively steep upward gradient in pressure or temperature measurements after cooling can be examined in historical data. This steep upward gradient often corresponds to landing events, so the load state can be changed to loaded. Similarly, low temperatures at cruise altitude can allow flight cycles to be identified by absolute temperature or by a relatively steep downward gradient in temperature or pressure measurements. Takeoff events can be identified by a relatively small absolute increase in pressure or temperature, or by a relatively shallow gradient of pressure and temperature following cooling.

[0047] The methods and applications discussed in this paper can be applied to any aircraft using a tire monitoring device, which can be instructed to periodically measure pressure and temperature and store these measurements along with associated timestamps. Figure 1 An example tire monitoring device is shown in the diagram below.

[0048] Figure 1 A schematic diagram of a tire sensing or tire monitoring device 10 for use with the methods and applications described herein is shown. The tire monitoring device 10 is configured to be mounted on a wheel, for example, via a mechanical connection to an opening on the wheel, thereby providing access to the tire. The tire monitoring device 10 includes a processor 100, a communication interface 102, an indicator 104, a power supply 106, a pressure sensor 108, a temperature sensor 109, a first memory 110, a second memory 111, and a time source 116.

[0049] Processor 100 can be any suitable processing device, including a microprocessor having one or more processing cores. In use, processor 100 coordinates and controls other components and can be operated to read computer program instructions and data from and / or write computer program instructions and data to memory 110, 111.

[0050] Communication interface 102 is connected to processor 100 and is used to transmit and receive data from other devices within the tire pressure sensor system. In this example, the communication interface is a wireless communication interface comprising two transceivers 112, 114, both using different wireless technologies. The first transceiver 112 is configured for relatively long-range communication, up to approximately 50 m or approximately 100 m. For example, the first transceiver can use communication standards suitable for mobile devices, such as IEEE 802.15.1, IEEE 802.15.4, or IEEE 802.11 (Wi-Fi) based on the 2.4 GHz or 5 GHz Industrial Scientific and Medical (ISM) bands or the Wireless Avionics Internal Communications (WAIC) standard. The first transceiver also includes encryption modules for encrypting transmitted data and decrypting received data, for example, according to the Advanced Encryption Standard (AES) using a pre-shared key. The second transceiver 114 is configured for relatively short-range communication. For example, the second transceiver 114 can use standards according to IEEE 802.15, such as IEEE 802.15.4, RFID, or Near Field Communication (NFC). The second transceiver can operate within a range of less than 5m, less than 3m, less than 1m, less than 50cm, less than 25cm, less than 10cm, less than 5cm, less than 1cm, or where contact between devices is required. Like the first transceiver 112, the second transceiver 114 also includes an encryption module for encrypting transmitted data and decrypting received data.

[0051] In some examples, a single wireless transceiver can be provided within the wireless communication interface. In that case, the single transceiver can be used for relatively short-range or relatively long-range communication, or the range can be adjusted as needed (e.g., by controlling the transmission power).

[0052] Indicator 104 is connected to and controlled by processor 100 to provide indications to the user of the tire pressure sensor system. In this example, the indicator is an LED, but in other examples, the indicator is another form of light, a display such as an LCD or e-ink display, or any other form of visual indication. In other examples, the indicator is an audible indicator, such as a buzzer, a loudspeaker, a speaker, or any other sound-generating component. In still other examples, the indicator may include both audible and visual indication components. The indicator provides at least a first indication and a second indication, such as a first color and a second color of light. Additional indications may also be provided, such as steady or flashing light. The tire monitoring device has a housing (not shown), and indicator 104 can provide indications external to the housing, such as an LED that may be mounted externally to the housing or visible through the housing, or it may emit sound from inside the housing.

[0053] Power source 106 provides power to the components of the sensing device. The power source can be a battery, such as a lithium battery. In this example, the power source is a lithium battery with sufficient charge to allow the sensor to operate normally for several years, such as two to three years. In other examples, the power source may include, for example, a power harvesting system for collecting vibrations and / or electromagnetic radiation to charge a capacitor or battery, which then powers the device.

[0054] During use, tire monitoring devices may spend most of their operational lifespan in "sleep" or low-power mode, in which most components, except for the processor and wireless communication interface, are powered down. This conserves battery life. For example, a tire monitoring device may default to low-power mode, listening for commands to measure or report tire pressure. In this low-power mode, the device can be scheduled or otherwise woken up at predetermined intervals or times to sense pressure and temperature and store the results. For example, pressure and temperature can be sensed every minute, every 5 minutes, every 10 minutes, every 15 minutes, every 20 minutes, every 30 minutes, every hour, or every 2 hours and stored for trend monitoring. It has been found that measuring every 10 minutes provides a good balance between saving power and providing useful data for historical trend monitoring.

[0055] Pressure sensor 108 is connected to processor 100 and can be any suitable sensor for measuring pressure, such as a capacitive sensor. Similarly, temperature sensor 109 is connected to processor 100 and can be any suitable sensor for measuring temperature, such as a thermocouple. Temperature sensor 109 is arranged to indirectly measure the temperature of the gas inside the tire by measuring the temperature associated with a portion of a sensing device that is thermally coupled to the gas through a connection with the wheel.

[0056] The connection between pressure sensor 108 and temperature sensor 109 and processor 100 can be digital, providing a digital representation of the measured pressure and / or temperature from an analog-to-digital converter (ADC) within the sensors themselves, or analog, in which case the processor may include an ADC to sample the received signals. Including pressure and temperature sensors may help determine temperature-compensated pressure values.

[0057] This example includes two storage elements 110 and 111. In this example, memory 110 is a non-volatile, rewritable memory, such as a flash memory that can retain data without requiring power. Other examples may include volatile memory that is powered by a power source, or a combination of read-only and rewritable memory. Memory 110 is connected to processor 100 and is used to store computer program instructions and data executed by the processor, such as data from pressure sensor 108 or data received via wireless communication interface 102. Therefore, memory 110 is configured to store historical records of pressure and / or temperature readings sensed by pressure sensor 108 and temperature sensor 109. This historical record can be stored for at least the longest period between pressure measurements used for tire maintenance, such as at least three days. This ensures that sufficient historical records are retained to provide detailed information since the last tire pressure reading for maintenance, so that the historical records can be transmitted along with current pressure measurement data for trend analysis. In other examples, longer historical record periods may also be retained. For example, readings from the previous ten days may be stored, and once the memory is full, the oldest data is replaced with the latest data, such as using a first-in-first-out (FIFO) structure or a similar structure.

[0058] Memory 111 is secure memory, with write and / or read access restricted, for example, only to certain processes running on processor 100. Configuration data, such as wireless encryption keys, can be stored in memory 111. In other examples, a single memory may be provided, or memories 110 and 111 may be provided in a single physical device with logical partitions between memory 110 and memory 111.

[0059] The tire monitoring device 10 also includes a time source 116, such as a counter or real-time clock. The time source provides a value indicating the current time to indicate when the measurement was performed; for example, the processor 100 can associate the current value of the time source with each pressure and temperature measurement when it is stored in memory for use as a timestamp.

[0060] A timestamp can be an indication of actual time (such as Coordinated Universal Time, UTC). A timestamp can also be a relative measurement, such as a counter value, where the counter is initialized at a certain point in the use of the tire monitoring system, for example, when the tire monitoring system is first put into use. When using relative timestamps, the timestamp can be converted to real-time time by recording the values ​​of the timestamps at known times and taking into account the increment intervals of the counter.

[0061] Time source 116 does not need to be synchronized with other tire monitoring devices on the same aircraft because the method of using historical data described herein can be applied independently to the data of each monitoring device. When it is necessary to view data from more than one tire monitoring device on a common timeline, timestamps can be converted to a common reference timeline. For example, the current time when a forced tire pressure measurement is performed can be recorded along with the corresponding value of the timestamp and used for conversion.

[0062] Tire monitoring devices 10 are installed on each wheel of the aircraft. Figure 2 The example aircraft 200 is depicted in the text. Figure 2 This is a schematic diagram of the front view of an Airbus A320 aircraft. The aircraft has six wheels; four wheels are part of the main landing gear 210, and two wheels are part of the nose landing gear 220. Therefore, the aircraft 200 has six tire monitoring devices. Other aircraft models may have different numbers of wheels, and therefore may have different numbers of tire monitoring devices. For example, the Airbus A380 has twenty-two wheels, and therefore will have twenty-two tire monitoring devices.

[0063] In one example, the aircraft may include a tire monitoring system integrated with the aircraft's central system, such that the tire monitoring device itself communicates with the central system. For example, the aircraft may be equipped with a monitoring system that can be accessed via an interface in the aircraft's cockpit and / or via a separate maintenance system when on the ground. An example of an aircraft with a central tire monitoring system is the Airbus A380.

[0064] In another example, the tire monitoring system can be a standalone system that operates independently of other aircraft systems. Such a system can be provided on new or retrofitted aircraft to add functionality to existing aircraft. An example of such a system is described in EP-3 498 501A1, which is incorporated herein for all purposes.

[0065] Figure 3 Method 300 is described, which can be implemented by tire monitoring device 10 to store historical records of temperature and pressure measurements. First, at block 302, device 10 measures pressure and temperature using pressure and temperature sensors. At block 304, the current time is read from a time source. Next, at block 306, the pressure and temperature measurements, along with associated timestamps based on the time read from the time source, are stored in memory. A single data structure can be used to store pressure, temperature, and timestamps; pressure and timestamps can be stored in a separate data structure; or pressure, temperature, and timestamps can all be stored separately and associated with a public key, such as an index number. A single data structure may reduce storage requirements, but it allows for greater flexibility.

[0066] Pressure can be stored in any suitable unit, such as psi, atm (standard atmospheric pressure), or kPa. Similarly, temperature can be stored in any suitable unit, such as ℃ or K. Timestamps can be values ​​from a time source or represented relative to a real-time time base, such as Coordinated Universal Time (UTC).

[0067] Boxes 302, 304, and 306 repeat at predetermined intervals. These predetermined intervals can be managed by querying a timer, scheduling at appropriate time intervals at interrupts, or any other suitable method. The predetermined intervals can be regular, such as measurements every 1 minute, 5 minutes, 10 minutes, 15 minutes, 20 minutes, or 30 minutes. Measurements every 10 minutes have been found to strike a good balance between energy saving and collecting sufficient historical data for useful analysis. Figure 3 As depicted, at box 308, it is determined whether a predetermined time interval has elapsed. If yes, the method proceeds to box 302 for another measurement; otherwise, the method proceeds to box 310.

[0068] Tire monitoring devices can provide multiple stored data points to the requesting device in response to a request from another device, such as a maintenance unit or a central maintenance system. Figure 3In the method, at box 310, while waiting for the next measurement task, the tire monitoring device can monitor requests received through the communication interface and provide responses, for example, by determining whether a request for historical data has already been received at box 310. If a request has been received, execution proceeds to box 312; otherwise, execution returns to box 308.

[0069] At box 312, a communication interface is used to provide at least a portion of the stored data to the requesting device. For example, the request may specify a time period for the data, or the device may transmit the most recent data within a predetermined time period, such as data from the last day, the last 3 days, or the last 10 days. In other examples, all data in the memory is provided to the requesting device.

[0070] according to Figure 3 The method allows tire monitoring devices to measure and store data related to changes in pressure and temperature over time and provide that data to the requesting device. Although Figure 3 The use of logic tests in boxes 308 and 310 has been described, but other examples can use event-driven structures.

[0071] In the example of communication between the tire monitoring device and the aircraft's central system, each measurement may be transmitted to the central system for storage as it is acquired, as an alternative to or supplement to sending data in response to requests in boxes 310 and 312.

[0072] exist Figure 4 The diagram depicts what can be seen from the above reference. Figure 1 Example data collected by the tire monitoring device under discussion. Figure 4 Simulated pressure and temperature data of the aircraft were depicted for eight 1-hour flights on the first day, followed by a single 90-minute flight on the second day. Figure 4 The simulation depicts the time-varying variations of tire gas pressure 402 (right-hand axis), tire gas temperature 404 (left-hand axis), and ambient temperature at ground level 406 (left-hand axis). The simulation data comes from a two-dimensional computational fluid dynamics (CFD) model of the wheels, tires, and brakes (WTB). This model is an axisymmetric conjugate heat transfer model that calculates the temperature of all solid and fluid components.

[0073] Reference Figure 4The aircraft begins at time 0 with pressure and temperature equal to ambient pressure and temperature (20°C / 293K). During the first flight cycle, the low altitude causes a drop in pressure and temperature until landing. Landing introduces heat to the tires from multiple sources, including increased temperature at ground level, tire bending during landing, and heat radiated from braking system components such as brake discs. While the aircraft is stationary, the tires continue to heat up, for example, the brakes dissipate heat, warming the gases in the tires and continuing to increase the heat of the gases in the tires for a relatively short period—1 hour—while the aircraft is stationary. After takeoff, the lower altitude causes cooling, which can be seen over a period of 2 to 3 hours. Re-landing causes heat input and a heating period of 3 to 4 hours, until the aircraft takes off again. This cycle continues until the aircraft ceases operation and remains stationary overnight, from time 14 to time 23. During this stationary period, pressure and temperature peak at time 15 and then slowly decrease to ambient temperature. The 90-minute flight between 23 and 25 hours further cooled the tires before the temperature rose upon landing. Finally, the temperature and pressure rose to their peak again and then decreased to ambient temperature as the aircraft came to a standstill.

[0074] Figure 4 The graph illustrates how difficult it is to reliably measure tire pressure in commercial aircraft because tire pressure is constantly changing. To ensure the gas temperature inside the tires is close to ambient temperature for accurate pressure readings, it is currently mandated that the tires remain stationary for at least three hours before measurement, but such a period is not available for most of the day. Even after a three-hour period of rest, as... Figure 4 The time spent in the tires is 14 to 17 hours. Even after three hours of stillness, the tire gas temperature is still about 30°C higher than the ambient temperature.

[0075] also, Figure 4 The description depicts a simulated gas temperature, which is not necessarily the temperature measured when the temperature is indirectly sensed, as is the case with automatic tire monitoring systems. Indirect measurement refers to the fact that indirect temperature measurements may precede or lag the gas temperature in the tire, thus only allowing for accurate measurement of the gas temperature at specific times.

[0076] It has been found that, despite significant variations during aircraft operating cycles, historical data on pressure and temperature measurements can still be used to improve tire maintenance. By identifying steady-state points in the data, even though these are indirect measurements, the temperatures measured at these points remain a good representation of the gas temperature. For example, a steady-state point could be a location where the pressure and temperature (in Kelvin) both change by less than 2% over a 10- or 20-minute period. This is because the stability at this point implies that the system tends towards an equilibrium state, where the temperatures of all components of the wheel system are approximately the same, making the indirect measurements approximate the actual gas temperature. For example, Figure 4 There are stable points at time intervals of 0 hours (indicated by arrow 408), 23 hours (indicated by arrow 410), and 34 hours (indicated by arrow 412). These stable points can then be used to determine pressure trends independent of the aircraft's operating cycle, as will now be described.

[0077] Figure 5 An example computer-implemented method for tire maintenance using historical data, which can be executed by a processing system, is described. First, at box 502, pressure and temperature measurements, along with associated timestamps, are received. For example, the data can be retrieved from a storage device or requested from a tire monitoring device.

[0078] Next, a stable point is determined at box 504. In this example, the stable point is determined by iteratively traversing the dataset and considering each pair of consecutive data points to establish the relative changes in pressure (in psi, kPa, or bar) and temperature (in K). If both changes are less than 2%, the pair of points is recorded as a stable point. Stable points can be stored in a separate dataset or otherwise labeled as stable, for example, by setting a flag associated with those data points in the dataset. In other examples, stable points can be identified by looking for a constant rate of change, such as by determining that the pressure and temperature gradients of consecutive data point pairs are within 2%.

[0079] Once a steady-state point is identified, the data is standardized at box 506 to express pressure measurements at a predetermined reference temperature, making the pressure data directly comparable. For example, a reference temperature of 15°C (288K) can be used. This standardization can be performed using any suitable technique. For an aircraft tire filled with nitrogen to a pressure of approximately 200 psi (1,380 kPa / 13.8 bar), it can be assumed that the gas in the tire behaves as an ideal gas and that the tire volume is constant. Based on these assumptions, a relationship can be used to standardize the pressure; for example, a 10K temperature change corresponds to a 3.7% pressure change. Alternatively, assuming an ideal gas and constant volume, the pressure can be converted using the ideal gas law as follows:

[0080]

[0081] Among them, P end The pressure P is the pressure presented at the desired temperature, such as the reference temperature. start It is the measured pressure, T end This is a reference temperature, and its unit is K or T. start It is the measured temperature, and its unit is K.

[0082] This standardized data can then be used, for example, at box 508, to fit a trend line to the pressure change over time using a linear regression with least squares. Least squares is computationally simple and works well in this application because it can be assumed that the tire pressure loss is a straight line between reinflation events. (A straight-line approximation is reasonable because the overall pressure change is small; the tire will be reinflated when it falls below 100% of its normal operating pressure). Other examples may use different methods to determine the trend line, including fitting a curve or a polynomial instead of a straight line.

[0083] Figure 6 Some example trend lines are shown, which may be generated once the stability points have been identified, standardized, and trend lines fitted to the stability points (the data here is illustrative, not based on test results). The first trend line 602 is the trend of the tire on the first wheel, while the second trend line 604 is the trend of the tire on the second wheel. It can be clearly seen that the deflation rate of the second wheel is faster than that of the first wheel.

[0084] return Figure 5 In box 510, determine any tire maintenance requirements. This determination can be made using stable data itself, such as tire maintenance determination based on absolute or standardized values. The determination can also use a trend line, which can indicate the health condition of the tires and whether maintenance is needed.

[0085] In one example, maintenance action can be indicated if the deflation rate, as indicated by the trend line, exceeds a predetermined threshold, such as 5% per day. A deflation rate exceeding the threshold indicates a tire failure that may not be identifiable from a single existing measurement—the pressure itself may be acceptable, but historical trends suggest a high deflation rate and the need to replace the tire and / or wheel.

[0086] In another example, if the trend line indicates a change in inflation over time but there is no corresponding inflation event, maintenance action can be indicated. Without an inflation event, there will be no change in inflation over time, thus indicating a malfunction in the tire monitoring system, which should be replaced.

[0087] In other examples, trend lines can be used to predict tire pressure at a future point in time and can potentially indicate maintenance actions. While the current pressure may be within acceptable limits so that no action is needed at the current time, trend lines can be used to predict pressure at future times, such as the time of the next tire pressure check. The next tire pressure check can be determined based on the mandatory maximum time between tire pressure checks. Examples of mandatory maximum time between tire pressure checks are the intervals defined in the aircraft's Maintenance Plan Document (MPD), such as 3 days for single-aisle aircraft like the Airbus A318, A319, A320, and A321, and 48 hours for other aircraft like the A380 and A350. Some operators may choose to use shorter tire pressure check intervals than defined in the MPD, so alternative time periods can be used in some examples. In other examples, a specific time period foreseen or a specific future date and time can be received as input for predicted pressure.

[0088] If the predicted tire pressure at a future time, such as the time specified in the maintenance plan document for the next tire pressure check, is below an acceptable limit, maintenance can be initiated now instead of waiting for the next measurement. This allows for more proactive tire maintenance and minimizes wear caused by underinflation, potentially improving safety and / or tire life.

[0089] Regardless of the maintenance action being instructed, it can be indicated in any suitable manner at box 512. For example, the user interface can indicate the need for maintenance. The user interface can be provided as part of the cockpit information system or as a separate maintenance device. For example, providing instructions on a separate maintenance device is useful when maintenance personnel are performing a tire pressure check. For example, providing instructions on a cockpit system as part of a pre-flight check is useful (e.g., because the system uses historical data, analyzing that data can constitute part of a pre-flight check to improve safety).

[0090] In some examples, maintenance actions can be triggered based on trend lines, in addition to or as an alternative to indicative maintenance actions. For instance, a nitrogen trolley might be deployed to an aircraft for refilling or tire changing programs.

[0091] Figure 5 This method can be performed by any suitable processing system, including the tire monitoring device itself. In some examples, Figure 5This approach is performed in a central maintenance facility, such as one maintained by the aircraft manufacturer, airline operator, or professional services contractor. The central system can transmit data via a computer network in response to tire pressure measurement checks. This can facilitate a broader analysis of tire performance across the entire fleet. When performed by a central maintenance system, planned maintenance based on historical data is also improved because it takes the anticipated destination into account. If re-inflation is predicted in the future, the central maintenance facility can schedule re-inflation when the aircraft next arrives at a destination with suitable facilities, but still before the predicted pressure drop becomes too low, thus improving maintenance.

[0092] Historical data can provide in-depth insights into the operation and maintenance of specific tires or aircraft. Historical tire gas pressure and temperature data can be analyzed to extract maintenance information, such as identifying tires with poor inflation performance or shorter lifespan compared to others; identifying when a tire should be inflated throughout its lifespan; and so on. This data can be used for inspections to confirm that tires are being maintained to the required standards, and can also serve as an indication of other maintenance problems, such as improper wheel assembly settings causing tire wear to occur faster than normal. By automating data collection, large, reliable datasets can be collected at a much higher measurement frequency than existing inspections, which may only be performed every three days.

[0093] Figure 7 The paper describes example standardized pressure data from the first tire monitoring device over a three-year period. Figure 8 Example standardized pressure data from the second tire monitoring device were depicted over the same three-year period. Figure 7 and Figure 8 The data depicted is representative and not real data, but it is ready to demonstrate trends and characteristics that can be identified from real data. Standardized data, such as... Figure 7 and Figure 8 The standardized data depicted can be determined by identifying stable points in historical data, which are then transformed as described above to be expressed at a common temperature. Then, when viewed over periods of several months or years—for example, at least three months, at least six months, at least one year, or at least two years—the standardized data reveals underlying inflation and deflation trends. Once the data is standardized, the pressure increase is due to tire inflation because, assuming the gas is ideal and its volume is constant, standardization means that the pressure increase cannot cause a decrease in temperature—the only remaining variable that might cause a pressure change. After an inflation event, the pressure gradually decreases over time due to leakage until the next inflation event. Although in Figure 7 and Figure 8The data described herein and mentioned below are standardized data, but directly measured data (unadjusted or standardized) are also useful as a substitute for or supplement to standardized data. For example, directly measured data can provide useful information about the absolute influence of temperature and operating environment, which can be used to determine the impact on inflation and deflation trends.

[0094] The depiction of standardized data makes it easy to see from the visible patterns. Figure 7 and Figure 8 The inflation-deflation cycle is described. Inflation can also be determined by analyzing data numerically, for example, by identifying the time it takes for the pressure to increase in gradients greater than 0.25 psi (1.7 kPa / 0.017 Bar), 0.5 psi (3.4 kPa / 0.034 Bar), or 1 psi (6.9 kPa / 0.069 Bar) per minute. This filters out any effects due to imperfect normalization, rather than simply looking for any increase in pressure. (The steady point is a good indicator of gas temperature, but it is still indirectly connected to a temperature sensor, which may introduce small errors.)

[0095] Similar gradient analysis can also be used to identify inflation events by using appropriate thresholds when pressure is not standardized. Although temperature also causes pressure changes, heating the gas in use does not increase pressure as rapidly as this, so gradient analysis of pressure data can be a reliable way to determine inflation events.

[0096] Inflation events can also be identified by looking for a step change in standardized pressure—from less than 100% of the tire's reference pressure to more than 105% of the tire's reference pressure, without a corresponding temperature change.

[0097] Another way to identify an inflation event is to compare the pressure gradient with the temperature gradient. If the temperature gradient indicates that the temperature is essentially constant but the pressure increases, this also indicates an inflation event. In the absence of a temperature increase or volume change, the only way to increase pressure is through inflation.

[0098] In addition to this inflation and deflation cycle, Figure 7 and Figure 8 The time scale of the charts also allows for the determination of tire variations. Figure 7 In the diagram, tire changes are indicated by arrow 702. Figure 8In the diagram, tire changes are indicated by arrow 802. Tire changes can be determined using data on changes in deflation rate and / or maximum or minimum pressure between inflation events. Changes in deflation rate may be due to changes in the junction area between the wheel and tire during tire replacement or due to changes in tire structure. Pressure changes may occur because the entire wheel typically changes when a tire needs to be replaced. Tire changes can be determined not only from historical data itself but also individually by querying maintenance records stored in a database that documents where tire changes have occurred. Tire changes can also be recorded by tire monitoring devices, which sense pressure drops during tire changes and record the tire change event at that time.

[0099] Figure 7 and Figure 8 It shows how historical data can be used to determine maintenance information both individually (i.e., considering a single wheel) and in combination (i.e., comparing data from at least two different wheels). Figure 7 and Figure 8 Each of these factors enables the determination of the lifespan of individual tires and allows for comparison of the performance of tires of different models or brands. When... Figure 7 Tire life and Figure 8 By making comparisons, further maintenance information and trends can be identified. Data shows that within the same time period, compared to... Figure 8 Compared to the wheels requiring six tire changes, Figure 7 The wheels only require three tire changes. By analyzing the data and determining the tire change frequency or the time interval between tire changes, differences in specific wheels can be identified. For example, Figure 8 Wheels can be identified as requiring maintenance because an increased replacement frequency indicates that the wheel's configuration will increase tire wear. Maintenance of such wheels can be indicated or scheduled when the tire replacement frequency exceeds a predetermined threshold, when the tire replacement interval is shorter than a predetermined threshold, or when any one or two of these characteristics differ from that of another wheel on the same aircraft by at least 20%, 30%, 40%, or 50%.

[0100] Historical data can also be used to identify poor maintenance practices or to confirm that sufficient maintenance has been performed. For example, data can reveal the minimum pressure of a tire in use between two consecutive inflations. If the minimum pressure is below a predetermined threshold, it may indicate poor maintenance: the tire was not inflated when it should have been. Furthermore, the severity of underinflation can be determined by determining how long the pressure remains below the threshold. If the duration of the under-threshold pressure condition is less than the specified time between pressure checks, such as 3 days, the situation may be less serious because it can be assumed that inflation was performed as soon as the under-threshold pressure condition was detected. However, a situation where the under-threshold pressure condition persists for more than the specified time between pressure checks is more serious because a longer interval indicates that inflation checks were not performed as required or that inflation checks were performed but underinflation was not identified for some reason. In other examples, timing other than the specified time between pressure checks can be used, such as intervals specified by a particular operator. This can be useful for ensuring that maintenance is performed to the required standards, such as when the aircraft is operating far from its maintenance base or when maintenance has been subcontracted to a third party.

[0101] Similarly, historical data can be used to identify tires in use, such as the maximum pressure between two consecutive inflates. This can also indicate poor maintenance; a tire may be overinflated to allow for longer intervals between inflations, but an overinflated tire may wear out faster. Overinflation can be identified by comparing the maximum pressure to a threshold and providing maintenance instructions when the pressure is exceeded, such as taking action to reduce tire pressure.

[0102] Further insights can be gained from historical data if additional data, such as information about the tires fitted to the wheels, is available, for example, from maintenance databases. Tire brands and / or models can be compared to identify the best-performing brands and / or models using in-service data without the need for expensive laboratory testing. Retreading or modifying aircraft tires is also common. Additional tire-related data can include retread counts, indicating how many times a tire has been retreaded. In-service performance, such as deflation rate and time before replacement, can then be compared to determine if it correlates with retreading and the number of times the tire has been retreaded.

[0103] If the tire monitoring device has access to GPS data, the GPS location can be correlated with historical tire pressure and temperature to indicate the location at the time of measurement. When location data is available, it can be combined with other maintenance data to identify any poorly performing maintenance locations, such as those where tires are consistently overinflated. GPS data can come from the GPS unit built into the tire monitoring device or from an external source, such as another system on the aircraft that is queried by the tire monitoring device.

[0104] While the above assumptions have used standardized data for this historical trend analysis, absolute measurements can also be used. This may be most useful for determining the number of times pressure exceeded a predetermined maximum measured pressure threshold or fell below a predetermined minimum pressure threshold, as actual pressure may differ significantly from standardized pressure (e.g., using unstandardized data). Figure 4 Changes in Figure 7 (Comparison)

[0105] Figure 9 The following method is described: This method allows for the analysis of historical data used to identify maintenance information or trends. The method is implemented by a processing system, such as a processing system forming part of a central maintenance system or a stand-alone maintenance unit.

[0106] At box 902, data from multiple tire gas pressure measurements are received, each with an associated time period. This data can span a predetermined period, such as the past six months, the past year, the past two years, the past three years, or longer. Alternatively, all data available for the tire can be received. The data can be received via a communication interface or from the memory of the device performing the method. The pressure data can be normalized relative to a reference temperature, for example by determining a settling point as described above, or the pressure data can be the actual measured pressure. Temperature data can also be included, which is particularly useful when the data is the actual measured pressure rather than a normalized pressure.

[0107] Next, at box 904, the received data is analyzed to determine maintenance information, which includes at least one of the following: inflation event, maximum pressure, minimum pressure, and tire change event. Any of the examples discussed above can be used to determine these events.

[0108] At box 906, an instruction based on the determined maintenance information is provided. This instruction can be visual or audible. For example, if historical data indicates no problem, the instruction might simply be "OK" or a green light. If there is a problem that needs to be addressed, such as a particular wheel being replaced more frequently, an appropriate instruction, such as "Maintain wheel 4," can be provided. When this method operates on a central maintenance system, the instruction can be related to the performance of a specific service location or service facility, such as "Service location 1 continues to overinflate tires."

[0109] In some examples, in addition to providing notification, the method may also include scheduling maintenance, such as scheduling wheel inspections when the aircraft is next at a maintenance location if tire replacements are too frequent.

[0110] exist Figure 9In this method, historical data can be stored locally or remotely. Remote storage allows independent maintenance units to access historical data when needed without requiring the unit itself to have large storage capacity. Remote storage also allows historical data to be aggregated across multiple maintenance locations.

[0111] In some examples, Figure 9 Methods could include associating unique tire identifiers with maintenance information in a database. Unique tire identifiers can identify tires independently of their installation on a specific aircraft. While tires in use can be identified by a combination of aircraft tail ID and wheel position, this is not suitable for identifying tires independently of the aircraft; for example, the same tire may change position and / or aircraft during its service life. Similarly, the same aircraft will have many different tires installed on it throughout its entire service life.

[0112] Unique tire identifiers can be numeric or alphanumeric. They can be displayed on the tire in any suitable manner, including barcodes (one-dimensional or two-dimensional), printed on the tire, embossed on the tire, or other visible markings. Unique tire identifiers can also be incorporated in an invisible way, such as using near-field communication (NFC) or radio frequency identification (RFID) tags embedded in or attached to the tire.

[0113] As mentioned above, aircraft tires can be refurbished multiple times during their operational lifespan. After refurbishment, a tire is unlikely to be reinstalled on the same aircraft and wheel position; in fact, it's even unlikely to be reinstalled on another aircraft belonging to the same operator. Unique tire identifiers allow historical data to be associated with specific tires. While paper-based systems can be used to track refurbishment events, this is susceptible to human error. Linking unique tire identifiers to historical information in a database can reduce human error and enable new safety features.

[0114] The database that associates unique tire identifiers with historical information is preferably stored remotely in a location accessible to the location where tire maintenance is performed, or stored in multiple locations so that the data is synchronized across these locations. Maintenance information can be associated with tires in various ways, such as by recording each specific maintenance detail for a tire, thus storing the tire's service history. Alternatively, maintenance information can simply be an indication of whether a tire is safe to use, making it easy to mark a tire as unsafe and prevent its reuse.

[0115] In one example, determining whether a tire is safe to use involves querying a database using a unique tire identifier to access data in the database. The database may have an application programming interface (API) that receives such queries and returns a "safe" or "unsafe" indication in response. This response may be based on at least one of the following indications in the database: the tire is marked as safe, no hazardous maintenance information for the tire is recorded in the database, and there is no data indicating that the tire should not be used. Alternatively, the database may respond to the query by returning maintenance information for the tire stored in the database, which is then interpreted by the device that sent the query.

[0116] In another example, data in the database is updated with specific maintenance information, such as by adding any specific, determined maintenance information along with a timestamp indicating the current date and / or time to the record. In some examples, historical measurement data, such as tire pressure and tire temperature, are also stored. This provides not only maintenance records but also tire operation records.

[0117] A database that associates tire maintenance data with unique tire identifiers can improve security. In one example, it reduces human error when checking whether a tire is safe to use. In another example, it can reduce human error in recording tire maintenance information—such as a tire being unsafe and no longer suitable—by automating database updates and eliminating the need for specific user input.

[0118] While retreading is a safe procedure and has environmental benefits such as extending tire life, it also has limitations. For example, retreading may not address wear on other tire components besides the tread, such as the sidewalls. Therefore, there are limits on the number of times a tire can be retreaded before it must be taken out of service, such as a maximum of seven retreads. One example is associating the retread count with a unique tire identifier, allowing the count to be determined by querying a database. For instance, a maintenance facility or factory handling tire retreading could access the database and recycle tires if the retread count is at its maximum. After the retreading operation, the maintenance facility can update the tire's retread count in the database.

[0119] Storing maintenance information in a database also enables improved reporting and inspection of hazardous tire operations. There are several operating conditions that, after which, regardless of whether the maximum retreading value has been reached, it is recommended to discontinue the tire and not to perform any further retreading.

[0120] Now refer to Figures 11 to 14 Describe examples of tires that are determined to be unsafe and should not be used even after retreading.

[0121] Figure 11 Representative historical pressure measurements 1102 for the example tire over time are depicted. These measurements are absolute values ​​or gauge pressures, uncorrected for temperature. The vertical axis represents a percentage of the reference pressure, so a value of 100% indicates the tire gas is at the reference pressure. As can be observed, the historical pressure measurements show a trend of gradual deflation after an inflation event. However, the pressure trend indicates that at any given moment, the time elapsed between re-inflation and a faster drop in tire pressure is longer than in other inflation cycles. Low inflation pressure can cause the tire to bend more than expected, thus reducing tire life. Figure 11 In the example, if the tire pressure is determined to be less than 90% of a predetermined decommissioning threshold at any point in the historical data, the maintenance information indicates that the tire should be decommissioned rather than reused. The database can be automatically updated with this information to prevent the tire from being unintentionally reused.

[0122] Figure 11 The pressure data shows that a re-inflation event occurred after the tire pressure dropped below 90%. However, by analyzing historical data, potentially dangerous low pressures can still be identified. This can be used to identify any poor maintenance practices and may provide retraining as needed. Alternatively or additionally, if additional operating conditions were determined while the tire was in use, after which the tire should be taken out of service, historical information can be used to apply these additional operating conditions to the installed tires so that any tires that need to be taken out of service can be decommissioned. For example, additional failure modes and their causes can be identified.

[0123] Go to Figure 12 This describes historical pressure data 1202 and 1204 for two tires mounted on the same axle. The database allows tires to be associated with related tires, such as tires mounted on the same axle. During a tire's lifespan, several other tires can be mounted next to that tire on the axle, so the data for related tires can also indicate the time period during which that tire was mounted on the same axle, or it can store only the current tire mounted on the same axle as that tire.

[0124] Figure 12The diagram shows a first tire with historical pressure data 1202 operating normally, but a second tire with historical pressure data 1204 exhibiting significant pressure loss, below 80% of the reference pressure. This pressure loss not only damages the tire by increasing flexural strength but also damages the tires on the same axle because they bear a greater load compared to when the tires are inflated more evenly. In this situation, when the tire pressure falls below 80% of a predetermined associated tire removal threshold, both the deflated tire and the associated tire mounted on the same axle update their maintenance information to indicate that they are no longer in use and will not be reused.

[0125] Figure 13 Historical pressure data 1302 and 1304 over time are shown for another pair of tires mounted on the same axle. In this case, both tires are operating independently within acceptable parameter ranges. Although pressure data 1304 indicates a faster deflation rate than pressure data 1302, pressure data 1304 remains above 90%. However, in this case, the varying deflation rate means that the pressure difference 1306 between the tires is greater than the predetermined pressure difference threshold of 20%. This also leads to uneven load distribution and increased wear, therefore both tires should be taken out of service and not reused. The database is updated with maintenance information accordingly.

[0126] Figure 14 Example pressure data is depicted for tires that should have been decommissioned but were inadvertently reinstated. Tire damage and wear are difficult to detect unless they are very severe, especially when a tire is decommissioned due to low pressure from another tire on the same axle (e.g., as described above regarding...). Figure 12 and 13 In the described situation, a visual inspection may indicate that the tire is not damaged. Figure 14 The discontinuity 1404 in the pressure data 1402 under tire disuse conditions is shown. The tire was then unintentionally brought back into use. By checking the database to determine if a tire is safe to use, it can be identified that a tire should not be used and needs to be removed and disposed of, even if historical pressure data shows it is operating within acceptable limits.

[0127] Figure 10 This is a schematic diagram of a system 1000 capable of performing the methods of the present invention. (Refer to the above text.) Figure 1 The multiple tire monitoring devices 1002 discussed are installed on the same aircraft. In this case, there are six tire monitoring devices 1002 for a six-wheeled aircraft, such as those mentioned above. Figure 2The Airbus A320 is discussed. The tire monitoring device 1002 communicates with the cockpit information system 1004, which includes a processing system 1006 and a communication interface 1008. The tire monitoring device also communicates with a separate maintenance device 1010, such as a smartphone running a suitable application or other portable or handheld device that can be used to query the sensors and receive historical measurement data from the tire monitoring device. Similar to the cockpit information system 1004, the maintenance device 1010 includes a processing system 1012 and a communication interface 1014. Figure 10 This is a schematic diagram of a system 1000 capable of performing the methods of the present invention. (Refer to the above text.) Figure 1 The multiple tire monitoring devices 1002 discussed are installed on the same aircraft. In this case, there are six tire monitoring devices 1002 for a six-wheeled aircraft, such as those mentioned above. Figure 2 The Airbus A320 is discussed. The tire monitoring device 1002 communicates with the cockpit information system 1004, which includes a processing system 1006 and a communication interface 1008. The tire monitoring device also communicates with a separate maintenance device 1010, such as a smartphone running a suitable application or other portable or handheld device that can be used to query the sensors and receive historical measurement data from the tire monitoring device. Similar to the cockpit information system 1004, the maintenance device 1010 includes a processing system 1012 and a communication interface 1014.

[0128] One or both of the cockpit information system 1004 and maintenance device 1010 also communicate with the central maintenance system 1016. The central maintenance system 1016 includes a processing system 1018, a communication interface 1020, and a database 1020. At predetermined times or in response to predetermined events, such as tire pressure measurements, the cockpit information system and / or maintenance device 1010 use the communication interface to transmit historical data of tire pressure and temperature measurements to the central maintenance system. This may include unique tire identifiers and specific maintenance information, such as instructions to deactivate the tires. The communication interfaces 1008 and 1014 of the cockpit information system and maintenance device may include separate interfaces for communicating with the central maintenance system, or the same interfaces may be used to communicate with the tire monitoring device 1002. For example, the maintenance device communicates with the tire monitoring device via a first wireless communication interface, such as according to the IEEE 802.11 standard or Bluetooth, and with the central maintenance system 1016 via a second wireless communication interface, such as a wireless communication interface according to a cellular standard, where the cellular standard is, for example, those defined by 3GPP or ETSI.

[0129] The term "processing system" includes systems having one or more processors (which may have one or more cores) and distributed processing systems that may be distributed across multiple physical devices and / or locations.

[0130] In the cases described above, the processing system can be implemented entirely in software, entirely in hardware (e.g., via an application-specific integrated circuit), or any combination of software and hardware. The software implementation may include a computer-readable medium comprising instructions instructing a processor to perform the method. The computer-readable medium may be a non-transitory computer-readable medium.

[0131] It should be noted that, unless otherwise expressly stated, the term “or” as used herein should be interpreted as meaning “and / or”.

[0132] The above embodiments should be understood as illustrative examples of the invention. Other embodiments of the invention are contemplated. It should be understood that any feature described with respect to any embodiment can be used alone or in combination with other described features, and can also be used in combination with one or more features of any other embodiment or any combination of any other embodiment. Furthermore, equivalents and modifications not described above may be employed without departing from the scope of the invention as defined by the appended claims.

Claims

1. A computer-implemented method for tire maintenance, comprising: Receive data, which includes multiple tire gas pressure measurements, each with an associated time. The received data is analyzed to determine maintenance information, wherein the maintenance information includes at least one of the following: inflation events, maximum pressure, minimum pressure, and tire replacement events; and Instructions are provided based on the identified maintenance information. The received data pertains to at least two tires on the same aircraft, and the analysis includes: Compare the determined maintenance information of the at least two tires; Determine the deflation rate of the at least two tires; and It is determined that the deflation rate of the first tire of the at least two tires is greater than the deflation rate of the other tire of the at least two tires.

2. The method of claim 1, wherein, The maintenance information includes minimum pressure, and the analysis includes: Determine the minimum pressure between two consecutive inflation events; and The minimum pressure is determined to be less than a predetermined threshold.

3. The method according to claim 2, further comprising determining a time period during which the pressure is less than the predetermined threshold.

4. The method of any one of claims 1 to 3, wherein, The maintenance information includes maximum pressure, and the analysis includes: Determine the maximum pressure between two consecutive inflation events; and The maximum pressure is determined to be greater than a predetermined threshold.

5. The method of any one of claims 1 to 3, wherein, The maintenance information includes inflation events and the analysis includes: Inflation events are determined by identifying positive pressure increase gradients greater than 1 psi per minute.

6. The method of claim 5, wherein, The analysis includes determining the inflation frequency or the interval between consecutive inflation events.

7. The method of claim 6, wherein, The analysis includes determining the frequency of tire replacements or the intervals between consecutive tire replacements.

8. The method according to claim 7, further comprising: Receive data including the number of tire retreads, and determine whether there is a correlation between the number of retreads and the inflation frequency, the interval between consecutive inflation events, the tire replacement frequency, or the interval between consecutive tire replacements.

9. The method according to any one of claims 1 to 3, further comprising standardizing the pressure data to express the pressure at a predetermined reference temperature.

10. The method according to any one of claims 1 to 3, further comprising scheduling maintenance actions based on the determined maintenance information.

11. The method of any one of claims 1 to 3, wherein, The received data includes receiving data having a unique tire identifier associated with the plurality of tire gas pressure measurements; the method further includes: The database is used to determine that the unique identifier of the tire corresponds to a tire that is safe to use.

12. The method of any one of claims 1 to 3, wherein, The received data includes receiving data formed by tire unique identifiers associated with the plurality of tire gas pressure measurements; The method further includes: The database is updated based on the maintenance information and the tire's unique identifier.

13. The method of any one of claims 1 to 3, wherein, The analysis includes determining the frequency of tire replacements or the intervals between consecutive tire replacements.

14. A processing system configured to implement the method according to any one of claims 1 to 13.

15. A computer-readable medium comprising computer-executable instructions that, when executed by a processing system, instruct the processing system to perform the method according to any one of claims 1 to 13.

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