Tire monitoring device and method

Abstract

A tire monitoring device configured to be mounted on a wheel and a method thereof are described. The device includes a pressure sensor to sense an inflation pressure of a tire on the wheel, a wireless communication interface configured to receive data representing a command to indicate the tire pressure, a memory to store a predetermined pressure value, an indicator configured to provide a first indication and a second indication, wherein the first indication is different from the second indication, and a processing system configured to operate the indicator to provide the first indication or the second indication in response to receiving the command to indicate the tire pressure and based at least in part on the inflation pressure and the predetermined pressure value.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to monitoring devices such as tyre monitoring devices and methods of their use and configuration. In examples, the present disclosure relates to aircraft tyre monitoring devices. BACKGROUND

[0002] Checking tyre pressure is an important part of vehicle maintenance. Tyre pressure should be maintained at a predetermined pressure to ensure that the tyre performs as intended by the manufacturer. Incorrect tyre pressure can lead to tyre failure, possibly bursting and causing damage to the vehicle and / or loss of control. Due to the high speeds encountered by tyres on aircraft landing gear, pressure is checked regularly, possibly once a day or more frequently. Manual checking of tyre pressure takes time and it would be beneficial to reduce this time.

[0003] It has been proposed to automate tyre pressure measurement by including a sensing device in the wheel, which can then be interrogated wirelessly to provide a measurement of the tyre pressure. This can reduce the time required compared to manual readings, but still takes time due to the need to measure pressure from wheel to wheel.

[0004] It is also important to ensure that the tyre pressure indicated by any automated measurement is accurate and / or reliable. This is not just that the measurement is accurate, but that the display itself shows an accurate representation of the pressure. This becomes more important when using a wireless interface, as the display can be more susceptible to damage due to glitches or malicious software on the display device.

[0005] It would be desirable to provide a tyre pressure measurement system which addresses some or all of these points. SUMMARY

[0006] According to a first aspect of the application, there is provided a tyre monitoring device configured to be mounted on a wheel. The device comprises: a pressure sensor for sensing an inflation pressure of a tyre on the wheel; a wireless communication interface configured to receive data representing a command requiring indication of the tyre pressure; a memory storing a predetermined pressure value; an indicator configured to provide a first indication and a second indication, wherein the first indication is different to the second indication; and a processing system. The processing system is configured to operate the indicator to provide the first indication or the second indication in response to receiving the command requiring indication of the tyre pressure and based at least in part on the inflation pressure and the predetermined pressure value.

[0007] Optionally, the wireless communication interface is configured to communicate with at least one other tyre monitoring device.

[0008] Optionally, the processing system is configured to operate the indicator to provide the first indication or the second indication based at least in part on data from the at least one other tyre monitoring device indicating the inflation pressure via the wireless communication interface.

[0009] Optionally, the wireless communication interface is configured to communicate with at least one other tyre monitoring device over a first network; and is configured to communicate with a control device over a second network; wherein the first network and the second network are separate.

[0010] Optionally, the wireless communication interface comprises a first transceiver and a second transceiver, the transmission range of the first transceiver being longer than the transmission range of the second transceiver.

[0011] Optionally, the second transceiver is configured for communication with a configuration device.

[0012] Optionally, the indicator comprises a visual indicator.

[0013] Optionally, the indicator comprises an audible indicator.

[0014] Optionally, the tyre monitoring device comprises a temperature sensor for sensing a temperature of the wheel or a temperature of a gas inside the tyre.

[0015] A tyre monitoring device as described above, with or without the described optional features, can be configured for use on an aircraft tyre.

[0016] In a second aspect, a tyre pressure measurement system can comprise a plurality of tyre monitoring devices as described above, with or without the described optional features, wherein the plurality of tyre monitoring devices are in communication with each other.

[0017] Optionally, the tyre pressure measurement system further comprises a control device. The control device comprises a wireless communication interface configured to send data indicative of a command to at least one of the plurality of tyre monitoring devices.

[0018] Optionally, the tyre pressure measurement system further comprises a configuration device, the configuration device comprising a wireless communication interface configured to send data indicative of a configuration command to at least one of the plurality of tyre monitoring devices.

[0019] Optionally, the transmission range of the wireless communication interface of the configuration device is less than 1 m.

[0020] According to a third aspect, there is provided a method of checking a tyre pressure using a monitoring device, the monitoring device comprising an indicator, a pressure sensor, and a wireless communication interface. The method comprises, at the monitoring device: receiving, via the wireless communication interface, data indicative of a request to check a tyre pressure from a control device; and in response to the request to check the tyre pressure: determining, using the pressure sensor, a first inflation state of a tyre associated with the monitoring device; and providing, using the indicator, an indication based at least in part on the first inflation state.

[0021] Optionally, the method includes determining a second inflation state of at least one other tire in response to the request to check tire pressure; and wherein providing the indication using the indicator is also based at least in part on the second inflation state.

[0022] Optionally, providing an indication using an indicator includes: providing a first indication using an indicator when at least one of (i) a first pressure measured by a pressure sensor is lower than a first predetermined threshold in a first inflation state and (ii) a second inflation state indicates that a second pressure is lower than a second predetermined threshold; and otherwise providing a second indication using an indicator, wherein the second indication is different from the first indication.

[0023] Optionally, the method further comprises sending the inflation pressure data to the control device using the wireless communication interface.

[0024] According to a fourth aspect, a method for configuring a monitoring device is provided, the monitoring device comprising a memory and a wireless communication interface. The method comprises: receiving, at the monitoring device, data indicating a first configuration message from a first device via the wireless communication interface; determining that a pressure measured by a pressure sensor is approximately zero; and entering a configuration mode in response to the configuration message and the determination that the pressure is zero.

[0025] Optionally, the method further comprises: receiving data indicating a second configuration message from the second device via the wireless communication interface when in the configuration mode; and setting the configuration parameters in the memory based on the second configuration message.

[0026] Optionally, data indicative of a first configuration message is received using a first wireless communication mode, and data indicative of a second configuration message is received using a second wireless communication mode.

[0027] According to a fifth aspect, there is provided a monitoring device with or without the optional features described, comprising: a memory; a pressure sensor; a wireless communication interface; and a processor configured to perform the method of the fourth aspect above.

[0028] Further features and advantages of the present invention will become apparent from the following description of preferred examples of the invention, given by way of example only, made with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of a tire pressure sensor system according to a first example of the present invention is shown.

[0030] Figure 2 Shown for Figure 1 Schematic diagram of a tire monitoring device used in an example.

[0031] Figure 3 Shown for Figure 1schematic diagram of a control device used in the example of

[0032] Figure 4 A flowchart showing an initial setup procedure for a tire monitoring device that can be used with the example of Figure 1

[0033] Figure 5 A schematic diagram of a tire pressure sensor network installed in an aircraft.

[0034] Figure 6 A flowchart showing a tire pressure check procedure that can be used with the example of Figure 1

[0035] A flowchart showing a tire pressure check procedure that can be used with the example of Figure 7 Figure 1 A flowchart showing a tire pressure check procedure that can be used by a tire monitoring device of

[0036] Figure 8 Figure 2 A flowchart showing a tire replacement procedure that can be used with the example of

[0037] Figure 9 A flowchart showing a tire replacement procedure that can be used with the example of Figure 1

[0038] A flowchart showing a tire monitoring device replacement procedure that can be used with the example of Figure 10 Figure 1 DETAILED DESCRIPTION

[0039] In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments. The specification description is not intended to imply any limitation on features described herein and the specification description can include both structural and methodological aspects of example embodiments. Embodiments described herein can be regarded as being operative on a system made of any combination of dded hardware and software components, and program elements including processors of personal computers, workstations, clients or servers.

[0040] Certain methods and systems described herein relate to operations on a sensor network in an aircraft. In examples described herein, a reference to an “aircraft” includes all types of aircraft, such as for example military or commercial aircraft, or fixed-wing aircraft of unmanned aerial vehicles (UAVs) and rotary-wing aircraft such as helicopters.

[0041] ​​​​​According to examples herein, a wireless tire monitoring system is provided in which an indication of status is provided both on the control device and on an indicator of the sensor itself. This provides an additional assurance of the results provided on the control device and can allow for the use of a control device such as a cell phone or tablet without the need for additional hardware to give assurance that the data displayed on the control device is correct. In some examples, the indication of a fault causes all tire monitoring devices to indicate a fault, even for tire monitoring devices in which there is no fault, making identification of the fault simpler.

[0042] According to examples herein, a wireless tire monitoring system includes three elements: a wireless tire monitoring device, a control device, and a configuration device. This makes the system secure and easy to use. For example, it can be required that the configuration device inputs some or all configuration commands to the wireless tire monitoring device, providing security by requiring a specific device for configuration. At the same time, ease of use can be improved by providing a control device which can be a mobile device running an application for performance of other functions, such as using the system to check tire pressure.

[0043] Examples are also described of methods of providing a configuration tire monitoring device to increase security, for example by requiring an additional authentication factor and a physical requirement that the tire monitoring device be in a configuration mode.

[0044] Figure 1 A schematic diagram of a tire pressure sensor system according to a first example of the invention is shown. The system includes a plurality of tire monitoring devices 10, a control device 12, and a configuration device 14, all arranged to communicate via wireless communication. The tire monitoring devices are mounted on each wheel of a vehicle, in this case an airplane (as explained in more detail below). The control device 12 is separate from the tire monitoring devices 10 and can be a dedicated control device that functions only in the tire pressure sensor system, or a computing device that can also be used for other purposes besides use with the tire pressure sensor system. Example computing devices include mobile devices such as laptops, tablets, cell phones, and wireless communication devices. Figure 5 The control device 12 is separate from the tire monitoring devices 10 and can be a dedicated control device that functions only in the tire pressure sensor system, or a computing device that can also be used for other purposes besides use with the tire pressure sensor system. Example computing devices include mobile devices such as laptops, tablets, cell phones, and wireless communication devices.

[0045] Figure 1Wireless communications in the tire pressure sensor system may use a local area network or a personal area network and may have any suitable topology including centralized and mesh wireless systems. In a centralized system, a single device may be designated as the master device to coordinate communications, or one or more additional wireless access points, gateways, or controllers (not shown) may be used. In some examples, the tire monitoring device 10, the control device 12, and the configuration device 14 may all utilize the same wireless technology to communicate and form a single network. In other examples, one or more of the tire monitoring device 10, the control device 12, and the configuration device 14 may be separated from the other elements of the system. Such separation may be provided in software, for example, by providing appropriate firewalls and / or using different network IDs and encryption keys. Such separation may also be provided by hardware, for example, through different wireless communication technologies. Both hardware and software separation may be combined. For example, in Figure 1 In the system, the control device communicates with the tire sensing device using a wireless communication technology different from that of the configuration device, which can improve the safety of the system.

[0046] Figure 2 Shown for Figure 1 Schematic diagram of a tire monitoring device 10 for use in a tire pressure sensor system. Tire monitoring device 10 is configured to be mounted on a wheel, for example, by mechanically connecting to an opening in the wheel that provides access to the tire. Tire monitoring device 10 includes a processor 200, a wireless communication interface 202, an indicator 204, a power source 206, a pressure sensor 208, a temperature sensor 209, a first memory 210, and a second memory 211.

[0047] The processor 200 may be any suitable processing device including a microprocessor having one or more processing cores. In use, the processor 200 coordinates and controls other components and may be used to read computer program instructions and data from and / or write computer program instructions and data to the memories 210 and 211. In some examples, the processor may be optimized for low-power operation or have at least one processing core optimized for low-power operation.

[0048] The wireless communication interface 202 is connected to the processor 200 and is used to send and receive data from other devices of the tire pressure sensor system. In this example, the wireless communication interface comprises two transceivers 212, 214, which use different wireless technologies. The first transceiver 212 is provided for relatively long range communication of up to about 50 m or about 100 m. For example, the first transceiver can use standards according to IEEE 802.11 (WiFi) to communicate on the 2.4 GHz or 5 GHz industrial scientific and medical (ISM) band, or can use the Wireless Avionics Internal Communications (WAIC) standard. The first transceiver also comprises an encryption module for encrypting transmitted data and decrypting received data, for example according to the Advanced Encryption Standard (AES) with a pre-shared key. The second transceiver 214 is provided for relatively short range communication. For example, the second transceiver 214 can use standards according to IEEE 802.15 such as Bluetooth (RTM), IEEE 802.15.4 or Near Field Communication (NFC). The second transceiver can operate at a range of less than 5 m, less than 3 m, less than 1 m, less than 50 cm, less than 25 cm between devices, or possibly requiring contact or less than 1 cm. Like the first transceiver 212, the second transceiver 214 also comprises an encryption module for encrypting transmitted data and decrypting received data.

[0049] In some examples, a single wireless transceiver can be provided in the wireless communication interface. In this case, the single transceiver can use either relatively short range or relatively long range communication, or adjust the range as needed, such as by controlling the transmitted power.

[0050] The indicator 204 is connected to and controlled by the processor 200 to provide an indication to a 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, pager, speaker or any other sound producing component. In further examples, the indicator can comprise both audible and visual indication components. The indicator provides at least a first indication and a second indication, for example a first color emitting light and a second color emitting light. Further indications such as a continuous or flashing light can also be provided. The tire monitoring device has a housing (not shown) and the indicator 204 can provide the indication externally of the housing, for example the LED can be mounted externally of the housing, or the sound can be able to be emitted from within the housing.

[0051] The power supply 206 provides power to the elements of the sensing device. The power supply 206 can be a battery such as a lithium battery. In this example, the power supply is a lithium battery with sufficient power to run the sensor for about 2 to 3 years in normal operation. In other examples, the power supply can include a power harvesting system that collects vibrations and / or electromagnetic radiation to charge a capacitor or battery, which is then used to power the device.

[0052] In use, the wireless sensing device can spend most of its operational lifetime in a "sleep" or low power mode, such that most components are powered down except the processor and the wireless communication interface. This can conserve battery life. For example, a tire monitoring device can default to a low power mode, listening for commands to measure or report tire pressure. Since tire pressure readings can be required relatively infrequently, perhaps only once a day, this can provide useful power savings. In other examples, pressure can be sensed more frequently, for example every 10 minutes, 15 minutes, 20 minutes, 30 minutes, 1 hour or 2 hours, and the pressure can be stored for use in trend monitoring.

[0053] The pressure sensor 208 is connected to the processor 200, and can be any suitable sensor for measuring pressure, for example a capacitive sensor. Similarly, the temperature sensor 209 is connected to the processor 200, and can be any suitable sensor for measuring temperature, such as a thermocouple. The temperature sensor 209 can be arranged to measure the temperature of the wheel or the temperature of the gas inside the tire directly. In the case that the temperature sensor 209 measures the temperature of the wheel, the temperature of the wheel can be processed to determine the temperature of the gas in the tire. For example, an algorithm or look-up table can be used.

[0054] The connections of the pressure sensor 208 and the temperature sensor 209 to the processor 200 can be digital, providing a digital representation of the measured pressure and / or temperature from an analog-to-digital converter (ADC) or similar in the sensor itself, in which case the processor can include an ADC to sample the received signal. Including both a pressure sensor and a temperature sensor can be useful to determine temperature-compensated pressure values. Although this example includes a pressure sensor and a temperature sensor, other examples can include only a pressure sensor, or can include additional sensors.

[0055] The example includes two memory elements 210 and 211. In this example, memory 210 is a non-volatile re-writable memory such as flash memory that can retain data without the need to apply power. Other examples can include volatile memory that is kept powered by a power supply, or a combination of read-only and re-writable memory. Memory 210 is connected to processor 200 and is used to store both computer program instructions for execution by the processor, and data such as data from pressure sensor 208 or data received through wireless communication interface 202. In some examples, memory 210 can store a history of pressure and / or temperature readings sensed by pressure sensor 208 and temperature sensor 209. For example, the last ten days of readings can be stored, with the newest data replacing the oldest data once the memory is full.

[0056] Memory 211 is a secure memory, with write and / or read access restricted, for example, to only certain processes running on processor 200. Configuration data such as wireless encryption keys can be stored in memory 211. In other examples, a single memory can be provided in a single physical device, or memories 210 and 211 can be provided with a logical division between memory 210 and memory 211.

[0057] Figure 3 A schematic diagram of a control device 12 for use in the example of Figure 1 The control device 12 includes a processor 300, a display 302, an input system 304, a power supply 306, a wireless interface 308, a memory 310, and a wired communication interface 312. In this example, the control device is a mobile device such as a cellular telephone or a tablet computer.

[0058] Processor 300 is any suitable processing device that can include one or more processing cores, such as a multipurpose microprocessor, a system on a chip, or a system in a package. Processor 300 is connected to a display 302 such as an LCD, OLED, or e-ink display to display information to a user of the control device.

[0059] In this example, input system 304 includes a touch screen interface that enables a user to interact with the control device by touching user interface elements on the screen. Input system 304 can include one or more buttons in addition to the touch screen, as well as other input devices such as a microphone for voice recognition and a camera for image input. Other examples can not include a touch screen interface.

[0060] The control device is powered by a power supply 306, which in this example is a rechargeable lithium-ion battery. Other examples can use alternative power supplies such as other battery technologies, mains power, or energy harvesting such as solar power.

[0061] Wireless interface 308 is included to enable control device 12 to communicate with other devices in the tire pressure sensor system. In this example, a single wireless interface 308 is provided that is configured to communicate with tire monitoring device 10. For example, relatively long-range wireless communication technology, such as wireless communication technology that complies with the IEEE 802.11 family of standards, may be used. This enables control device 12 to interact with relatively remote tire monitoring devices.

[0062] In other examples, the control device may be provided with multiple transceivers operating with different wireless technologies such as IEEE 802.11 and IEEE 802.15.4.

[0063] Memory 310 includes non-volatile components such as flash memory and volatile components such as RAM. The non-volatile components are used to store operating system software and application software. In this example, the control device runs standard operating system software and is loaded with application software for interacting with the tire pressure sensor system. To limit access to the tire pressure sensor network, the application software can be provided from a secure source and not available to the public, and / or require credentials to be entered before operation.

[0064] Wired communication interface 312 is provided for connection to a computing system. Wired communication interface 312 may be, for example, a serial data connection such as a Universal Serial Bus (USB), a parallel data connection, or a network connection such as Ethernet. Wired communication interface 312 may enable the control device to communicate values ​​read from the tire monitoring device and / or other status information to the computing system, for example, to store long-term trends and assist in fleet management. Alternatively or additionally, wireless communication interface 308 may be used to communicate with the computing system.

[0065] Figure 4 Shown for Figure 1 FIG2 is a schematic diagram of a configuration device 14 used in an example of FIG2 . Configuration device 14 generally includes the same elements as control device 12: a processor 400, a display 402, an input system 404, a power source 406, a wireless 408, a memory 410, and a wired communication interface 412, and unless otherwise described below, these are generally the same as those described above for the control device. In this example, the configuration device is a mobile device, but is limited to operating only with a tire monitoring system. For example, the configuration device may be a computing device or tablet computer capable of running software for interacting with the tire monitoring system.

[0066] In this example, the wireless communication interface 408 of the configuration device is a relatively short-range communication system, such as IEEE 802.15.4, Bluetooth (RTM), NFC or RFID. As will be explained in more detail below, this enables the configuration device to be used as an additional authentication factor when configuring the tyre monitoring devices.

[0067] The wired communication interface 412 of the configuration device can be used to provide information to the configuration device in a secure manner, for example enabling some encryption keys to be updated through a wired interface such as a serial data connection rather than a wireless interface.

[0068] In some examples, the configuration device 14 can be omitted and its place taken by the control device 12. The control device 12 can comprise a short-range wireless communication interface such as IEEE 802.15.4, Bluetooth (RTM) or NFC. Application software can be loaded onto the control device to enable the control device to also be used as an additional authentication factor, possibly by controlling operation of the short-range wireless communication interface for transmission of configuration commands by maintaining a cryptographic key that can only be accessed with suitable credentials.

[0069] Figure 5 A schematic diagram of a network of tyre pressure sensors installed in an aircraft is shown. The aircraft 500 comprises a fuselage 510, wings 520, a main landing gear 530 and a nose landing gear 540. According to examples, the aircraft 500 comprises a network of sensors according to any of the examples described herein. The aircraft 500 can be used in conjunction with any of the methods described herein. According to examples, a plurality of wireless nodes are distributed at various locations around the aircraft 500. For example, in the landing gears 530, 540 and wings 520 and in the fuselage 510. Tyre monitoring devices are installed on each wheel of the main landing gear 530 and the nose landing gear 540.

[0070] In examples, the tyre monitoring devices also communicate with a cockpit system to provide tyre pressure information to a pilot on the flight deck. In these examples, the flight deck console can also be used as a control device.

[0071] Figure 6 A flowchart showing an initial setup procedure for a tyre monitoring device that can be used with examples of Figure 1 A flowchart showing an initial setup procedure for a tyre monitoring device that can be used with examples of Figure 5 This procedure is used when no tyre pressure sensor devices are fitted to a vehicle such as an aircraft of Figure 6 Figure 6 ​The process can be used to retrofit or as part of a manufacturing process. Prior to starting the process, a set of tire monitoring devices are provided. For example, there can be one tire monitoring device for each wheel that is desired to be monitored for pressure, or there can be more than one tire monitoring device (e.g., to provide redundancy in the pressure measurement of the tire on one or more wheels).

[0072] First, at block 602, the control device 12 is used to start a tire pressure sensor system control application. The application presents a user interface on a display that includes an option "System Settings". The "System Settings" option is selected by the user, for example, through interaction with a touchscreen input of the control device 12.

[0073] Next, at block 604, the application on the control device 12 prompts the user to input configuration information for a first wheel for which a tire monitoring device is to be installed. This can include one or more of "wheel position", "vehicle identification", and "reference pressure". For example, the wheel positions for an aircraft can be "Front Right", "Front Left" for the nose landing gear, and "1", "2", "3", "4" for the main landing gear. The reference pressure can be specific to a particular wheel or wheels of the vehicle, for example, the main landing gear wheels can have a different reference pressure than the nose landing gear wheels. The "vehicle identification" can be the aircraft tail identification. Once the information is input, the user selects an option such as "Upload" to store the information in the application. The control device then periodically broadcasts that it has configuration parameters available for upload and waits to receive a communication from a tire sensing device to be installed in a wheel. In some examples, the controller device can provide a display or other prompt to cause the tire sensing device to be prepared to be configured with the input parameters. For example, a visual or audible prompt can instruct the user to "touch tire sensing device with configuration device".

[0074] Block 604 can also include sending the data to other devices, for example, a server system in a local area network or another network such as the internet to a secure server. In some examples, the vehicle identification and reference pressure in block 604 can be automatically populated by taking a photograph of the vehicle identification with the control device, determining the identification using optical character recognition, and then looking up the reference pressure in a database, which can be on a server or stored locally in the memory of the control device itself. In other examples, a bar code or other form of coded identification can be read by the control device.

[0075] Next, at block 606, the user provides a configuration command to the tire sensing device to be installed in the wheel. In some examples, this is provided by contacting the tire sensing device with the configuration device 14, which provides the configuration command using short range communication such as NFC. The tire sensing device then enters a configuration mode and listens for control devices broadcasting configuration parameters. The configuration command can include a network key, enabling the tire sensing device to join the tire sensor network in order to listen for control devices broadcasting.

[0076] At block 608, the tire monitoring device contacts the control device and establishes a secure communication session, such as by exchanging session keys for encryption and configuration parameters communicated from the control device in the configuration command. The tire sensing device stores the configuration parameters in its memory and exits the configuration mode. Because the tire sensing device measured zero pressure, the processor of the tire sensing device directs the indicator to provide a "fault" indication, such as a continuous red light for a predetermined period of time. In some examples, the communication with the control device uses a different communication mode or technology than the communication with the configuration device, for example using a longer range technology such as IEEE 802.11.

[0077] At block 610, the tire monitoring device is fitted to the wheel. Assuming that the pressure measured by the pressure sensor is above a predetermined threshold of the reference pressure loaded at block 608, the processor directs the indicator to provide an "OK" indication, such as a continuous green light for a predetermined period of time. In this example, the predetermined threshold is about 89% of the reference pressure. In other examples, the predetermined threshold can be about 95% of the reference pressure, about 90% of the reference pressure, or about 85% of the reference pressure.

[0078] At block 612, it is determined whether there are additional tire monitoring devices to be installed. If so, execution returns to block 604 and the configuration process is repeated for a different wheel. If there are no longer tire monitoring devices to be installed, execution continues to block 614.

[0079] At block 614, correct operation of the sensor system is confirmed. This may include internal checks using data provided to the control device during the configuration process. For example, checking that wheel reference pressures are consistent, checking for consistent reference pressures between the nose landing gear wheels, checking for consistent reference pressures between the main landing gear wheels, and checking for consistent vehicle identification across all wheels. Confirming correct operation may also include checking that the pressures measured by the pressure sensors match the manual measurements for each wheel, for example by prompting the user to perform a manual measurement for each wheel and accessing the control device. Confirming correct operation may also include obtaining and displaying data using the configuration device and checking that the data matches the required data. This may prevent damage to the control device, for example, if data has become corrupted, causing the displayed value to mismatch the actual value. Confirming correct operation may be fully or partially automated; for example, in some examples, all checks that do not require manual inspection may be automated.

[0080] although Figure 6 The process has been described as using a control device and a configuration device, but in some examples, a single device can function as both the control device and the configuration device. For example, a device can have both a long-range transceiver and a short-range transceiver (in the same manner as a tire sensing device) and be configured to use each appropriately.

[0081] Figure 7 Shows that once the sensor system has been established, it can be used with Figure 1 Flowchart of a tire pressure check process for use with an example of a tire pressure check. First, at block 702, a user initiates a tire monitoring control application on control device 12. Next, at block 704, the control device scans for tire monitoring devices within range. This may include establishing direct, point-to-point contact, or establishing contact through a network of tire monitoring devices, such as an access point, a master device, or any device in a mesh network. Scanning may include waking the tire monitoring device from a low-power mode. Scanning may include using a secure network key to communicate with the sensor network.

[0082] At block 706, the control device displays the identifier of the detected vehicle. Depending on the communication range and location, more than one vehicle may be detected. For example, several aircraft may be located on the same pylon within the range of the control device.

[0083] At block 708, the user selects the desired identifier. A command is then sent to the tire monitoring device corresponding to the identifier, causing the tire monitoring device to read the pressure and report back to the control device. A response is received at block 710 and displayed on the control device at block 712. The pressure display may include a numerical value and one or both of a status indication, such as "OK" or "low pressure."

[0084] At block 714, cross-checking of the received data can be performed to ensure data consistency. The process then ends.

[0085] Throughout Figure 7 the process, communication between the control device and the sensor device can be secured, for example encrypted by a network key. The network key used for communication with the control device can be different from the network key used for communication between the sensor devices, to enhance security of the system.

[0086] When exchanging security keys, security can be increased by utilizing a wireless communication technology with a limited transmission distance, for example the 802.11 (WiFi) standard can allow transmission at a distance of 50 m or further in a clear space. This alone can be sufficient to provide increased security, as physical proximity is required to intercept the communication. In some examples, when transmitting the encryption key, security can be increased by reducing the transmission power compared to the transmission of the encrypted data itself, requiring closer proximity for the initial key exchange process.

[0087] Figure 8 A flowchart of a tire pressure check process that can be used by a tire monitoring device of Figure 2 the system is shown. The process is provided to provide additional assurance and fault tolerance in pressure measurements from the system, for example to prevent a damaged operation or error in the control device. Through the process, the monitoring device uses its indicator to provide an indication of the tire pressure status independently of the control device.

[0088] First, at block 802, the tire monitoring device receives a command to check pressure through the wireless communication interface. In response, at block 804, the processor measures the pressure in the tire using the pressure sensor. The measured pressure is then compared to a reference pressure at block 806 to determine if the tire has low pressure. In this example, low pressure occurs if the pressure sensed by the pressure sensor is less than 89% of the reference pressure. Other examples can determine low pressure when the measured pressure is less than 95% of the reference pressure, less than 90% of the reference pressure, or less than 85% of the reference pressure. If low pressure is detected, execution proceeds to block 808, otherwise execution proceeds to block 812.

[0089] At block 808, the processor indicates the fault condition using the indicator, for example by providing a continuous red light for a predetermined period. For example, the predetermined period can be 5 minutes, 2 minutes, 1 minute, or 30 seconds. At block 810, the processor also broadcasts the fault indication to other tire monitoring devices again using the wireless communication interface.

[0090] At block 812, the processor checks to see if any fault messages have been received from other tire monitoring devices via the wireless communication interface. Such fault messages can be received directly via other tire monitoring devices or through a hub or access point. In this example, at block 808, such a fault message is received after the transmission of the fault indication, without first being requested. In other examples, the fault message can be received in response to a status query sent by the tire monitoring device to other tire monitoring devices. If any fault messages are received, execution proceeds to block 814, at which the processor displays the fault condition using the indicator. For example, the fault indication can be the same as the fault indication used in block 808. In other examples, the fault indication can be different from the fault indication used in block 808, for example a second fault indication such as a flashing red light for a predetermined period. By utilizing a second fault indication, the tire monitoring device can indicate a fault in another tire, still indicating the signal that the pressure it measures is not low.

[0091] If no fault messages are received at block 812, execution proceeds to block 816, at which the processor provides an "OK" indication using the indicator. For example, by providing a continuous green light for a predetermined period. For example, the predetermined period can be 5 minutes, 2 minutes, 1 minute or 30 seconds. In this way, an "OK" indication is only given when all tire monitoring devices have determined that the pressure of their associated tire is not low.

[0092] Finally at block 818, data of the measured tire pressure is transmitted in response to a command. The data can include further information such as the stored reference pressure, the determined status and the wheel position. The transmission of additional information can allow to verify the correct operation of the tire monitoring device as well as to check that the configuration data stored in the memory has not changed or has been set correctly. The transmission in block 818 can be transmitted directly to the control device 12, to another tire monitoring device 10 for onward routing, or to an access point or other wireless node.

[0093] With the method of Figure 8 the confirmation of the tire pressure status is provided by the tire monitoring devices themselves. A fault in any sensor will cause all sensors to indicate a fault.

[0094] In other examples, instead of transmitting a fault indication at block 810, all tire monitoring devices can instead transmit their measured pressure to other tire monitoring devices. The received pressure can then be independently checked by each individual tire monitoring device to determine if there is a fault. This can prevent a fault of a sensor not indicating a low pressure condition, for example if the stored reference pressure has been corrupted.

[0095] In further examples, when it is determined in block 806 that the tire pressure is not low, the tire monitoring device can send an "OK" status notification. Such examples can provide assurance that all sensors are operating correctly, as no data was received indicating a malfunction or failure in the tire monitoring device.

[0096] Figure 9 A flowchart of a tire replacement procedure that can be used with examples of Figure 1 It is necessary to periodically replace tires on a vehicle, which can occur within the lifetime of a tire monitoring device. To reuse an existing tire monitoring device, the following procedure can be used.

[0097] First, at block 902, the tire monitoring device is removed. The tire monitoring device will then read a zero pressure, so the indicator will be controlled by the processor to indicate a failure. At step 904, the failure indication is checked. If there is no indication of a failure, the tire monitoring device is faulty and should be replaced. At block 906, a new tire monitoring device is installed following, for example, the procedure of Figure 10 .

[0098] If there is an indication of a failure, at block 908 the tire is replaced and the tire monitoring device is reassembled. Then, at block 910, the indicator is checked for an "OK" indication. If there is an "OK" indication, the procedure ends. If there is no "OK" indication, the tire monitoring device is faulty, it is discarded at block 906 and a new one is assembled.

[0099] In some examples, the operation of the reassembled tire monitoring device can be further confirmed, for example, by checking the measured tire pressure against a manual measurement.

[0100] With the procedure of Figure 9 , tire replacement is also used to verify that the tire monitoring device is working correctly.

[0101] In some examples, the "OK" indication in block 910 can also include a battery life check to ensure that the expected battery life of the expected tire monitoring device is long enough for the device to last until the estimated next tire replacement. For example, the processor can associate a measured pressure of approximately zero (when the device is removed from the wheel) with a tire replacement, and perform a battery check when non-zero pressure is again measured by the pressure sensor.

[0102] Figure 10 A flowchart of a tire monitoring device replacement procedure that can be used with examples of Figure 1 The procedure is used to replace a tire monitoring device with a new tire monitoring device, for example, due to a failure.

[0103] At block 1002, the tire monitoring device is removed from the wheel. Configuration data is then deleted from the removed device at block 1004 to ensure that the tire monitoring device is not inadvertently reinstalled. For example, block 1004 can include using the configuration device 14 to erase the data of the tire monitoring device by sending a configuration command to it to erase its data.

[0104] Next, at block 1006, configuration data for a new tire monitoring device is entered into the control device. The configuration data is then loaded to the new sensing device at block 1008, for example by following the above process of blocks 606 and 608. At block 1010, the new tire monitoring device is attached to the wheel. Proper operation of the system can then be confirmed at block 1012.

[0105] In some examples, the configuration of the new tire monitoring device can be automatically cloned from the removed device and copied to the new device. For example, block 1004 can include reading and storing the configuration data before erasing it, which is then used to configure the new device at block 1008. Block 1006 can then be omitted or instead display the configuration data to the user to confirm that it is correct before loading to the new device.

[0106] Although the above process describes using short-range communication for some of the configuration commands, other examples can use long-range communication for these commands and distinguish themselves by, for example, using a different encryption protocol.

[0107] Although the above process describes using a general-purpose mobile device as the control device, the control device can also be a dedicated device that only provides for use with the tire monitoring system or more generally with a vehicle. This can improve security as more control is available.

[0108] Although the above process describes using indicators that are lights, other examples can use other indicators such as displays and / or audio components. For example, instead of simply displaying a continuous or flashing color, a display can also display information of the measured pressure itself. In cases where both audio and visual indicators are provided, some indications can not use both. For example, an "OK" indication can use only a visual indicator, while an audio indicator is only activated on a fault.

[0109] In all of the above processes, additional safety can be obtained by having the tire monitor device enter configuration mode and / or accept configuration commands only when the sensed pressure is approximately zero, such as less than 35 kPa (less than 5 psi). This ensures that the tire monitor device cannot be reconfigured while mounted on a wheel with an inflated tire. Additional safety can also be provided by automatically exiting configuration mode when the sensed pressure is no longer approximately zero. Additional or alternative safety can also be provided by one or more of the following: setting a limit on the amount of time the tire monitor device can be in configuration mode; and automatically exiting configuration mode upon completion of configuration, such as after completion of a configuration command.

[0110] It should be noted that the term "or" as used herein is to be interpreted as "and / or" unless otherwise expressly stated.

[0111] The above examples are to be understood as illustrative examples of the application. It should be appreciated that any feature described in relation to any one example can be used alone or in combination with other features described, and that the means of entry of these features can be combined with any of the examples, or any combination of the examples, and in the same way, the means of exit of these features can be combined with any of the examples, or any combination of the examples. Furthermore, equivalents and modifications not described expressly invention as defined by the following claims.

Claims

1. A tire monitoring device configured to be mounted on a wheel and comprising: a pressure sensor for sensing the inflation pressure of the tire on the wheel; a wireless communication interface configured to receive data representing a command requesting an indication of tire pressure, wherein the wireless communication interface is configured to communicate with at least one other tire monitoring device; a memory for storing a predetermined pressure value; an indicator configured to provide a first indication and a second indication, wherein the first indication is different from the second indication; and a processing system configured to, in response to receiving the command requesting an indication of tire pressure and based at least in part on the inflation pressure, the predetermined pressure value, and data indicating inflation pressure from the at least one other tire monitoring device via the wireless communication interface, operate the indicator to provide the first indication or the second indication.

2. The tire monitoring device according to claim 1, wherein: The wireless communication interface is configured to: communicating with the at least one other tire monitoring device via the first network; and communicating with the control device via a second network; The first network and the second network are independent.

3. The tire monitoring device according to claim 1 or 2, wherein: The wireless communication interface includes a first transceiver and a second transceiver, the first transceiver having a longer transmission range than the second transceiver.

4. The tire monitoring device according to claim 3, wherein: The second transceiver is configured to communicate with a configuration device.

5. The tire monitoring device according to claim 1 or 2, wherein: The indicator includes a visual indicator.

6. The tire monitoring device according to claim 1 or 2, wherein: The indicator includes an audible indicator. 7 . The tire monitoring device according to claim 1 , comprising a temperature sensor for sensing the temperature of the wheel or the temperature of gas inside the tire.

8. The tire monitoring device of claim 1 or 2, configured for use on aircraft tires.

9. A tire pressure measurement system comprising a plurality of tire monitoring devices according to any one of claims 1 to 8, wherein: The plurality of tire monitoring devices are in communication with each other.

10. The tire pressure measurement system according to claim 9, comprising: A control device includes a wireless communication interface configured to transmit data indicative of a command to at least one of the plurality of tire monitoring devices.

11. The tire pressure measurement system according to claim 9 or 10, comprising: A configuration device includes a wireless communication interface configured to send data indicative of a configuration command to at least one of the plurality of tire monitoring devices.

12. The tire pressure measurement system according to claim 11, wherein: The transmission range of the wireless communication interface of the configuration device is less than 1m.

13. A method for checking tire pressure using a monitoring device, the monitoring device comprising an indicator, a pressure sensor, and a wireless communication interface, the method comprising, at the monitoring device: receiving data indicating a request to check tire pressure from a control device via the wireless communication interface, wherein the wireless communication interface being configured to communicate with at least one other tire monitoring device; as well as In response to the request to check tire pressure: determining a first inflation state of a tire associated with the monitoring device using the pressure sensor; and An indication is provided using the indicator based at least in part on the first inflation state and a second inflation state of at least one other tire from the at least one other tire monitoring device via the wireless communication interface.

14. The method according to claim 13, wherein Providing an indication using the indicator includes: providing a first indication using the indicator when at least one of (i) the first inflation state is a first pressure measured by a pressure sensor below a first predetermined threshold and (ii) the second inflation state indicates a second pressure below a second predetermined threshold; and Otherwise, a second indication is provided using the indicator, wherein the second indication is different from the first indication.

15. The method according to claim 13 or 14, further comprising: The tire pressure data is sent to the control device using the wireless communication interface.

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