Patent Application
20240051355
The present invention relates to a sensor device configured to measure at least one property of a wheel assembly, to a wheel assembly comprising such a sensor device, to an aircraft comprising such a wheel assembly, and to a method of determining an operational parameter of a vehicle.
Monitoring properties of vehicle wheel assemblies, such as tire inflation, tread depth, and tire damage is an important part of vehicle maintenance. This is particularly true for aircraft, since the wheel assemblies of an aircraft routinely experience large loads and harsh operating conditions. Currently, many such checks of aircraft wheel assembly properties are performed manually, and involve a different process for each property. Automated systems exist for monitoring tire pressure, but these systems require a pressure sensor to be permanently installed on a wheel in a manner specific to the particular design of the wheel. For instance, the wheel must typically include a port to accommodate the sensor, and possibly also a counterweight feature. For other important wheel assembly properties which must be regularly checked no automated measurement systems exist.
The invention set out below seeks to provide an improved sensor device for use in determining at least one property of a wheel assembly.
A first aspect of the present invention provides a sensor device for use in determining at least one property of a wheel assembly comprising a tire mounted on a wheel. The sensor device is configured to be attachable to an outer circumferential surface of the wheel which faces an inner circumferential surface of the tire. The sensor device is configured to measure a distance between the sensor device and an object remote from the sensor device.
Optionally, the sensor device is configured to measure any or all of: a distance between the sensor device and the inner circumferential surface of the tire, when the tire is mounted on the wheel; and a distance between the sensor device and the ground, when the wheel assembly is operating to support a vehicle.
Optionally, the sensor device is configured to be movably attachable to the outer circumferential surface of the wheel such that the sensor device is able to continuously travel around the circumference of the wheel in a given direction whilst the wheel remains stationary.
Optionally, the sensor device is configured to emit radiation in a direction toward the remote object when the sensor device is attached to the wheel; and to detect a reflection of the emitted radiation.
Optionally, the sensor device is configured to continuously emit the radiation and to continuously detect the reflection during a time period in which there is relative circumferential movement between the sensor device and the wheel.
Optionally, the sensor device is configured to emit the radiation in the form of a beam directed to align with a radial direction of the wheel when the sensor device is attached to the wheel.
Optionally, the sensor device is configured to emit a first beam of radiation in a first direction which is towards the inner circumferential surface of the tire when the sensor device is attached to the wheel, and a second beam of radiation in a second, different direction which is towards the inner circumferential surface of the tire when the sensor device is attached to the wheel. Optionally, an angle between the first beam and the second beam is less than 90°.
Optionally, the sensor device comprises a sensor controller configured to operate the sensor device according to a predetermined measurement protocol.
Optionally, the sensor controller is configured to select the predetermined measurement protocol from a set of two or more predetermined measurement protocols stored on a memory of the sensor controller, based on any one or more of: a command signal received by the sensor controller; a relative rotation state of the sensor device and the wheel; a parameter relating to the operation of a vehicle on which the wheel assembly is installed.
Optionally, at least one of the predetermined measurement protocols in the set is a scanning measurement protocol suitable for use only when there is relative rotation between the sensor device and the wheel.
Optionally, the predetermined measurement protocol is any one of: a damage measurement protocol; a tread depth measurement protocol; a load measurement protocol.
Optionally, a damage measurement protocol comprises emitting radiation such that it is incident on a substantially full width of an inner surface of a tire mounted on the wheel, and detecting reflections of the emitted radiation from the substantially full width of the inner surface of the tire, continuously over a time period in which the sensor device moves around at least a full circumference relative to the wheel.
Optionally, a tread depth measurement protocol comprises emitting a first beam of radiation such that it is incident on an inner surface of a tire mounted on the wheel and detecting reflections of the first beam from the inner surface; and emitting a second beam of radiation such that it is incident on a support surface in contact with an outer surface of the tire and detecting reflections of the second beam from the support surface.
Optionally, a load measurement protocol comprises emitting radiation such that it is incident on a reference circumferential surface of the tire, the reference surface having a known distance from an inner circumferential surface of the tire, and detecting reflections of the emitted radiation from the reference circumferential surface of the tire.
Optionally, the sensor device is further configured to measure one or more of: tire pressure; tire gas temperature; acceleration.
Optionally, the sensor device is further configured to measure tire pressure, and the load measurement protocol further comprises measuring tire pressure substantially simultaneously with emitting the radiation.
A second aspect of the invention provides a wheel assembly comprising a wheel having an outer circumferential surface configured to face an inner circumferential surface of a tire mounted on the wheel; and a sensor device according to any preceding claim attached to the outer circumferential surface of the wheel.
Optionally, the wheel assembly further comprises a tire mounted on the wheel, and the tire comprises a circumferential portion of reflective material which is configured to reflect a greater proportion of the emitted radiation than a material which forms the main body of the tire.
Optionally, the wheel assembly is an aircraft wheel assembly.
A third aspect of the invention provides an aircraft comprising a wheel assembly according to the second aspect.
Optionally, the aircraft further comprises an avionics system in communication with the sensor device.
A fourth aspect of the invention provides a method of determining an operational parameter of a vehicle. The method comprises:
Optionally, the sensor is mounted on the wheel and the distance measured is a distance between the sensor and an object remote from the sensor.
Optionally, the method comprises:
Optionally, the wheel is rotated about its axis between performing the distance measurement and performing the further distance measurement.
Optionally, the method comprises comprising performing a series of distance measurements, the series including the distance measurement and the further distance measurement, and each measurement of the series is performed when the sensor is at a different circumferential location relative to the wheel, and wherein the different circumferential locations are distributed around the circumference of the wheel.
Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:
The following description provides several examples of sensor devices according to the invention. Each example sensor device is suitable for use in determining at least one property of a wheel assembly comprising a tire mounted on a wheel. Each example sensor device is configured to be attachable to an outer circumferential surface of the wheel which faces an inner circumferential surface of the tire. Furthermore, each example sensor device is configured to measure a distance between the sensor device and an object remote from the sensor device.
Example sensor devices according to the invention provide several advantages. Being configured to be attachable to an outer circumferential surface of a wheel which faces an inner circumferential surface of a tire mounted on the wheel means that the sensor device is located inside an enclosed space formed by the wheel and the tire and therefore has direct access to the gas in the tire and can perform accurate measurements of the properties of that gas. It also means that the sensor device is protected from the external environment of the wheel assembly and may therefore need to be less robust than a sensor device mounted externally on a wheel assembly.
Being configured to measure a distance between the sensor device and a remote object (which may be, for example, a part of the wheel assembly, a part of a vehicle in which the wheel assembly is comprised, or the ground) enables the sensor device to acquire measurement data from which various properties of the wheel assembly can be determined, meaning that multiple properties of a wheel assembly can be automatically monitored using just one sensor device. The manner in which these advantages are provided by the example sensor apparatus according to the invention will be explained further in the following description.
In examples described herein, references to “aircraft” include all kinds of aircraft, such as fixed wing military or commercial aircraft; unmanned aerial vehicles (UAVs); and rotary wing aircraft, such as helicopters.
It should be noted that the components shown in the drawings are not necessarily shown to scale.
The wheel assembly 1 is a wheel assembly for a vehicle. In some examples the wheel assembly 10 is an aircraft wheel assembly. In such examples the wheel 13 comprises an inboard wheel rim (comprising one of the flange parts 133a and a section of the hub part 132) and an outboard wheel rim (comprising the other one of the flange parts 133b and a further section of the hub part 132). The inboard wheel rim may house a brake assembly (not shown). The outboard wheel rim includes a valve (also not shown) for inflating the tire 14. To construct such an aircraft wheel assembly, the inboard and outboard wheel rims are bolted together with the tire 14 in between. The tire 14 is then pressurised via the valve, usually with nitrogen. The sensor device 10 may be attached to the wheel 13 before the inboard and outboard wheel rims are bolted together.
The sensor device 10 is configured to acquire measurement data. The sensor device 10 may be configured to acquire a single type of measurement data, or multiple types of measurement data. In some examples the sensor device 10 comprises a set of multiple sensors, each of which may be configured to independently acquire measurement data. Each sensor in the set may acquire a different type of measurement data, or two or more sensors in the set may acquire the same type of measurement data. The sensor device 10 is configured to acquire distance measurement data, and in some examples may additionally be configured to acquire any or all of the following types of measurement data: tire gas temperature; tire pressure; acceleration; acoustic noise data; vibration data. The sensor device 10 may be configured to use any suitable known sensing technology to acquire the measurement data, depending on which type(s) of measurement data the sensor device 10 is intended to acquire. The architecture of the sensor device 10 is explained in detail below with reference to
The sensor device 10 is configured to measure a distance between the sensor device 10 and an object remote from the sensor device. Such an object may be, for example, any or all of: the tire 14; the ground 16; a further component of the wheel assembly 1; a component of a vehicle in which the wheel assembly 1 is comprised. The illustrated example sensor device 10 is configured to measure a distance between the sensor device 1 and the inner circumferential surface of the tire 14 (when the tire 14 is mounted on the wheel 13) and also a distance between the sensor device 1 and the ground 16 (when the wheel assembly 1 is operating to support a vehicle).
In the illustrated example, the sensor device 10 is configured to measure a distance between the sensor device 10 and the remote object by emitting radiation 11 in a direction toward the remote object, and detecting reflections of the emitted radiation which are reflected by the remote object. The sensor device may be configured to emit the radiation 11 in the form of a beam of radiation. Such a beam of radiation may be directed to align with a radial direction of the wheel 13 when the sensor device 10 is attached to the wheel 13. The radiation 11 may be any type of radiation which will be at least partly reflected by the remote object to which it is desired to measure a distance. Suitable types of radiation may include light, radio waves, sound waves (e.g. ultrasound) or the like. In some examples (particularly examples in which the remote object comprises a metallic element) the sensor device 10 is a Hall effect sensor. The sensor device 10 may be configured to emit the radiation in discrete pulses and to detect the reflection of each pulse. Alternatively the sensor device 10 may be configured to continuously emit the radiation and to continuously detect the reflection during a time period.
Part (iii) of
The second beam 12 may be substantially the same as the first beam 11 except for the angle at which it is emitted, or it may differ from the first beam 71 in terms of, for example, energy, wavelength, frequency, width, or any other property. The angle of the second beam 12 is such that it is incident on (and at least partially passes through) a side wall of the tire 14. By contrast, the first beam 11 is incident on a circumferential wall of the tire 14 (that is, a wall of the tire which is in contact with the ground 16). The angle of the second beam 12 may be selected in dependence on factors such as the configuration of the tire 14, the distance it is desired to measure using the second beam 12, or the like.
The second beam 12 may be configured to measure a different distance to the first beam 11. For example, the first beam 11 may be configured to measure a distance d1, which is the shortest distance between the sensor device 10 and the inner circumferential surface 141 of the tire 14, whilst the second beam 12 is configured to measure a distance d2 between the sensor device 10 and the ground 16. The distance d2 is not the shortest distance between the sensor device 10 and the ground 16 because of the angle of the second beam 12. However; the shortest distance d3 between the sensor device 10 and the ground 16 can be calculated from d2 using trigonometry. In some examples, when the wheel assembly 1 is supported on the ground 16, a first part of the first beam 11 may be reflected by the inner circumferential surface of the tire 14 and a second part of the first beam 11 may be reflected by the ground 16. In such examples the first beam 11 may be used to measure both the distance d1 and the distance d3.
In the illustrated example the portion of reflective material is a reinforcing band which functions to strengthen the tire 24. In other examples the portion of reflective material need not provide any such structural function.
The sensor device 10 is configured to emit the first beam of radiation 11 radially outwardly, and is also configured to emit a second beam of radiation 22 at an angle θ to the first beam 11. The angle θ is selected such that the second beam 22 is not incident on the reinforcing band 27. The first beam 11 is incident on the reinforcing band 27. The reinforcing band 27 may be made of a metallic material which reflects substantially all of the part of the first beam 11 which is incident on the reinforcing band 27 (a part of the first beam 11 may be reflected by an inner circumferential surface 241 of the tire 24 before reaching the reinforcing band 27). The properties of the first beam 11 may be selected such that substantially all of the first beam 11 is incident on the reinforcing band 27 (that is none, or only a small part, of the first beam 11 is reflected by the inner circumferential surface 241 of the tire 24). The first beam 11 is configured to be used to measure the shortest distance between the sensor device 10 and the inner surface of the reinforcing band 27 (which is directly related to the shortest distance between the sensor device 10 and the inner circumferential surface 241 of the tire 24).
The second beam 22 is configured to measure a distance between the sensor device 10 and the ground 16. The properties of the second beam 22 are selected such that at least a part of the second beam 22 is incident on the ground 16. The properties of the second beam 22 may be selected such that substantially all of the second beam 22 is incident on the ground 16. The material of the reinforcing band 27 may have properties such that it would be impossible or impractical for the sensor device 10 to emit a beam of radiation that could even partially pass through the reinforcing band 27 to reach the ground 16. The angle θ of the second beam 22 therefore advantageously enables at least part of the second beam 22 to be incident on the ground 16, so that a distance between the sensor device 10 and the ground 16 can be measured. This would not be possible using the first beam 11 in this example, because of the blocking effect of the reinforcing band 27.
Returning to
A movable attachment of the sensor device 10 to the wheel 13 in various ways. For example, the sensor device 10 could be fixedly attached to a mounting band which is moveably mounted on the wheel 13 such that the mounting band is able to move circumferentially relative to the wheel 13. Such a mounting band may, for example, encircle the outer circumferential surface 131 of the hub part of the wheel 13. The circumferential movement may be facilitated, for example, by providing a low friction surface on one or both of an inner circumferential surface of the mounting band and the outer circumferential surface 131 of the wheel 13.
An alternative way of movably attaching the sensor device 10 to the wheel 13 is illustrated in
The mounting member 32 comprises a fixed mounting band configured to be fixedly attached to a circumferential surface of a wheel. The sensor device 10 is movably attached to the fixed mounting band 32 such that the sensor device 10 is able to move around the circumference of the fixed mounting band 32. The fixed mounting band 52 is a closed loop configured to encircle the circumferential surface 131 of the hub part 132 of the wheel 13. The diameter of the fixed mounting band 32 is substantially equal to the diameter of the circumferential surface of the hub part of the wheel 13, at least when the fixed mounting band 32 is mounted on the wheel 13. The diameter of the fixed mounting band 32 may be adjustable, to facilitate installing it onto the wheel 13.
An inner circumferential surface of the fixed mounting band 32 contacts the circumferential surface of the wheel 13. In some examples relative circumferential movement between the fixed mounting band 32 and the circumferential surface of the wheel 13 is prevented by mutually configuring the inner circumferential surface of the fixed mounting band 32 and the outer circumferential surface 131 of the wheel 13 to ensure a high coefficient of friction therebetween. In some such examples one or both of the inner circumferential surface of the fixed mounting band 32 and the outer circumferential surface 131 of the wheel 13 comprises a high-friction coating. In some examples the fixed mounting band 32 is configured to be tensioned when it is on the wheel 13. Alternatively or additionally, the fixed mounting band 32 may be configured to be fixed to the wheel 13 by an attachment mechanism such as a bonding agent, a mechanical interlock, and/or one or more fasteners. Any such attachment mechanism is selected to be suitable for an intended application of the sensor device 10.
The fixed mounting band 32 is substantially rigid and may be formed from any material appropriate to the particular application. The fixed mounting band 32 may comprise a continuous piece of material, or it may have a join. If the fixed mounting band 32 comprises a join, any joining mechanism used to form the join must be sufficiently robust and reliable to remain joined for at least a desired period (which may, for example, be equal to a battery life of a battery of the sensor device 10).
The sensor device 10 may be attached to the fixed mounting band 32 in any manner which enables the sensor device 10 to travel circumferentially around the fixed mounting band 32 when the sensor apparatus 30 is mounted on the wheel 13, whilst preventing relative radial and axial movement of the sensor device 10 and fixed mounting band 32. In the illustrated example, the fixed mounting band 32 comprises a circumferential rail 321 which extends completely around the circumference of the fixed mounting band 32. The sensor device 10 is movably mounted on the circumferential rail 321. The illustrated rail 321 has a T-shaped profile, although any other profile shape suitable for preventing radial and axial movement of the sensor device 10 relative to the fixed mounting band 32 could be used. In some examples the fixed mounting band 32 may comprise two or more circumferential rails. The rail 321 may be formed integrally with the main body of the fixed mounting band 32, or it may be fixedly attached to the main body of the fixed mounting band 32.
The sensor device 10 is contained within a housing which is configured to engage with the circumferential rail 321. The configuration of the housing is dependent on the configuration of the circumferential rail 321, because the housing is configured to mechanically interlock with the circumferential rail 321. In the illustrated example, the housing comprises a pair of L-shaped protrusions 311 extending from a radially-inner surface of the housing. The spacing of the L-shaped protrusions is selected such that the head of the T-shaped circumferential rail 321 is able to be received between the protrusions with little or no axial or radial clearance between the head of the circumferential rail 321 and the protrusions 311. The L-shaped protrusions 311 extend circumferentially by an amount sufficient to substantially prevent pivoting of the housing (and therefore of the sensor device 10) relative to the fixed mounting band 32. In other examples the illustrated configuration could be reversed—that is, the fixed mounting band comprises a pair of L-shaped circumferential rails and the housing comprises a T-shaped protrusion configured to be received between the L-shaped circumferential rails. The surfaces of the housing and the circumferential rail 321 which are in contact comprise bearing surfaces. These bearing surfaces may be configured to facilitate sliding therebetween, for example by comprising a low-friction material.
The mounting band 32 is configured to be installed on the wheel 13 before the tire 14 is fitted to the wheel 13, when the wheel 13 is in a disassembled state (that is, a state in which an inboard part and an outboard part of the wheel 13 are not joined together). The hub part 132 of either the inboard or the outboard part of the wheel 13 is inserted into the mounting band 32 such that the mounting band 32 encircles the hub part 132, and then the inboard and outboard parts of the wheel 13 are connected together. The sensor device 10 may be attached to the mounting band at the time of installing the mounting band 32 on the wheel 13, or it may be attached to the mounting band 32 after the mounting band 32 has been installed on the wheel 13. In some examples the mounting band 32 is tensioned after it has been arranged on the circumferential surface 131 of the hub part of the wheel 13. The installation may be performed manually by an operator, either during assembly of the wheel assembly 1 or during a maintenance process performed on the wheel assembly 1 (such as replacement of the tire 14).
The components 412-418 and wired connections 419 are all contained within the housing 411. The housing 411 is configured to protect the components 412-418 and connections 419 from the external environment, including from any impacts and vibrations that may be experienced during operation of the sensor device 10 on a vehicle. The material(s) and configuration of the housing 411 are selected to be suitable for the particular intended application of the sensor device 10. For example, if the sensor device 10 is intended for use on an aircraft wheel assembly, the housing 411 must be able to withstand the extremes of temperature that can be experienced in an aircraft tire (potentially between −55° C. and 275° C.). In some examples the housing 411 may comprise a thick layer of silicone rubber. The housing 411 may further comprise features configured to facilitate attachment of the sensor device 10 either directly to the wheel 13, or to a mounting member (such as the L-shaped protrusions discussed above in relation to
The first sensor component 415 comprises a distance sensor configured to emit the radiation 11 and to detect a reflection of the emitted radiation, in any of the manners described above. The distance sensor may 415 comprise any suitable sensor technology. The distance sensor 415 is configured to receive power from the power source 413. The distance sensor 415 is configured to receive control signals from the sensor controller 412. Such control signals may be configured to, for example, trigger the distance sensor 415 to perform a distance measurement. The distance sensor 415 is configured to send measurement data to the sensor controller 412.
When there is no relative movement between the sensor device 10 and the wheel 13, the region of the inner circumferential surface 141 of the tire 14 on which the first beam 11 is incident does not change, so the distance sensor 415 can only acquire measurements for this particular region. However; when there is relative rotation between the sensor device 10 and the wheel 13, a complete circumferential section of the inner surface 141 of the tire 14 will pass through the area where the first beam 11 is incident. This enables the distance sensor 415 to scan a whole circumference of the tire inner surface 141.
The distance sensor 415 is configured to obtain two different types of measurement data: a distance between the distance sensor 415 and the inner surface of the tire 14 (or between the distance sensor 415 and a reference surface a known distance from the inner surface of the tire 14), and a distance between the distance sensor 415 and the surface 16. Various physical properties of the wheel assembly 1, and even of a vehicle in which the wheel assembly 1 is comprised, can be determined by operating the distance sensor 415 according to various predefined measurement protocols. Some such predefined measurement protocols require relative circumferential movement between the distance sensor 415 and the wheel 13 and others do not. The sensor controller 412 is pre-programmed with such predefined measurement protocols and is configured to operate the distance sensor according to a currently selected measurement protocol, by sending control signals to the distance sensor 415. Some example predefined measurement protocols are described below with reference to
The distance sensor 415 is be configured to perform a distance measurement using the first beam 11, and/or (in some examples) the second beam 12 in response to receiving a control signal from the sensor controller 412. The distance sensor 415 may be configured to apply a time-stamp indicating the time at which the measurement was performed to each measured distance value. The distance sensor 415 is configured to send measurement data comprising at least one measured distance value to the sensor controller 412. The distance sensor 415 is configured to receive electrical power from the power source 413.
The second sensor component 416 of the sensor device 10 comprises a movement detector. The movement detector 416 may be configured to detect absolute movement of the sensor device 10. In such examples the output of the movement detector 416 may be used (e.g. by a processor of the movement detector 416 or by the sensor controller 412) in conjunction with data from a wheel speed sensor to detect relative movement of the sensor device 10 and the wheel 13. Alternatively the movement detector 416 may be configured to directly detect relative movement between the sensor device 10 and the wheel 13. The movement detector 416 may use any suitable technology to detect the absolute or relative movement. In some examples the movement detector 416 comprises an accelerometer. In such examples the movement detector 416 may be configured to, alternatively or additionally, determine an orientation of the sensor device 10 relative to the ground 16. Such orientation information can indicate when the sensor device 10 is at its lowest possible position and may be useful, for example, to check the direction of the radiation beam(s) emitted by the distance sensor 415.
The movement detector 416 may be configured to perform a measurement in response to receiving a control signal from the sensor controller 412, or may be configured to automatically perform measurements at periodic intervals, or may be configured to continuously perform measurements. Performing a measurement may comprise a simple determination that movement (either relative or absolute) is or is not occurring at the time of the measurement. Performing a measurement may comprise measuring a value of one or more parameters of any detected movement (such as speed, direction, and the like). The movement detector 416 may apply a time-stamp indicating the time at which the measurement was performed to each measured value. The movement detector 416 is configured to send measurement data to the sensor controller 412. The measurement data may comprise, for example, any or all of: an indication of whether or not relative movement is present; a rate of relative movement; a rate of absolute movement. The movement detector 416 is configured to receive electrical power from the power source 413.
The power source 413 may be any type of power source suitable for supplying electrical power to the other components 412 and 414-418 of the sensor device 10. The power source 413 may comprise a battery, such as a lithium battery. Such a battery should have sufficient capacity to power the normal operation of all of the other components of the sensor device 10 for at least a maximum service interval of a wheel assembly on which the sensor device 10 is installed (that is, a longest time period that may elapse between maintenance processes performed on the wheel assembly). A battery comprised in the power source 413 may have sufficient capacity to power all of the components of the sensor device 10 for a selected time period which depends on the intended application of the sensor package 6. In some examples the power source 413 may comprise an energy harvesting device of any suitable type. In some examples the power source 413 may comprise both a battery and an energy harvesting device, in which case the capacity (and therefore the size) of the battery may be able to be smaller than if no energy harvesting device were present.
The wireless communications interface 414 is configured to be operated by the sensor controller 412 to both transmit data to, and receive data from, one or more other devices remote from the sensor device 10. The wireless communications interface 414 includes at least one transceiver. More than one transceiver may be provided, each using different wireless technology and/or arranged to transmit and receive over different ranges. Any suitable form or forms of wireless communications technology may be used by the wireless communications interface 414. The wireless communications interface 414 is configured to receive electrical power from the power source 413. The wireless communications interface 414 is configured to receive control signals (including data to be transmitted by the wireless communications interface 414) from the sensor controller 412.
The optional third sensor component 417 comprises a temperature sensor. The temperature sensor 417 is configured to directly measure the temperature of gas inside the tire. The temperature sensor 17 may be any suitable sensor for measuring gas temperature within a tire, such as a thermocouple. The temperature sensor 417 may be configured to perform a measurement in response to receiving a control signal from the sensor controller 412, or may be configured to automatically perform measurements at periodic intervals, or may be configured to continuously perform measurements. The temperature sensor 417 may be configured to apply a time-stamp indicating the time at which the measurement was performed to each measured pressure value. The temperature sensor 417 is configured to send measurement data comprising one or more measured temperature values to the sensor controller 412. The temperature sensor 417 is configured to receive electrical power from the power source 413.
The optional fourth sensor component 418 comprises a pressure sensor. The pressure sensor 418 may be any suitable sensor for measuring gas pressure inside a tire, for example a capacitive sensor. The pressure sensor 418 may be configured to perform a measurement in response to receiving a control signal from the sensor controller 412, or may be configured to automatically perform measurements at periodic intervals, or may be configured to continuously perform measurements. The pressure sensor 418 may be configured to apply a time-stamp indicating the time at which the measurement was performed to each measured pressure value. The pressure sensor 418 is configured to send measurement data comprising one or more measured pressure values to the sensor controller 412. The pressure sensor 418 is configured to receive electrical power from the power source 413.
The sensor controller 412 is configured to operate the other components of the sensor device 10. In some examples the sensor controller 412 is configured to determine whether or not there is relative circumferential movement between the sensor device 10 and the wheel 13 at the current time, and to alter its operation in dependence on the result of the determination. For example, the sensor controller 412 may be configured to operate in a first mode if there is relative movement between the sensor device 10 and the wheel 13, and in a second, different mode if there is substantially no relative movement between the sensor device 10 and the wheel 10.
The first mode may be a scanning mode, in which the sensor controller 412 operates the distance sensor 415 to continuously emit radiation and continuously detect reflections of the emitted radiation, during a time period in which there is relative circumferential movement between the sensor device 10 and the wheel 13. Emitting the radiation continuously may mean that the radiation is emitted as one long pulse having a duration at least as long as the time period, or it may mean that the radiation is emitted in a series of discrete pulses at frequent intervals during the time period. If the radiation is emitted as a series of discrete pulses, the time interval between consecutive pulses is preferably short. The time interval between consecutive pulses may be set by the sensor controller 412 in dependence on a current rate of relative circumferential movement between the sensor device 10 and the wheel 13, with a relatively shorter time interval being used for a relatively higher rate of relative circumferential movement.
In a scanning mode of operation, the sensor controller 412 may operate the distance sensor 415 in a manner suitable to acquire measurement data covering an entire circumference of the remote object to which the distance is being measured. For example, where the remote object is the circumferential wall of the tire 14, the sensor controller 412 may operate the distance sensor 415 to acquire measurement data covering a continuous circumferential section of the inner circumferential surface 141 of the tire 14. Acquiring sufficient measurement data to cover an entire circumference may be achievable in a single rotation of the wheel 13 relative to the sensor device 10, or it may require multiple rotations of the wheel 13 relative to the sensor device 10.
The sensor controller 412 may be configured to receive data from one or more remote systems, such as an aircraft avionics system, via the wireless communications interface 414. Such data may relate to current operational conditions of a vehicle in which the wheel assembly is comprised. In some examples the sensor controller 412 may be configured to receive current wheel speed data from a remote system. In some examples the sensor controller 412 is configured to receive control commands from a remote system, for example configured to cause the sensor controller 412 to operate in a particular manner.
The sensor controller 412 comprises a processor and a memory unit. The memory unit may be used to store computer program instructions for execution by the processor; and data, such as measurement data received from the sensor components 415-418. The memory unit may include non-volatile rewritable storage, such as flash memory which can retain data without requiring applied power. Alternatively, volatile storage, which is kept powered by the power source 413, may be employed; or combinations of read-only and rewritable storage. The memory unit of the sensor controller 412 may be configured to store a history of measurement data received from one or more of the sensor components 415-418. The history may be stored for a predetermined amount of time, which may be at least as long as a maximum time between manual wheel assembly maintenance operations. The predetermined amount of time may therefore be determined based on the intended application of the sensor package 6. This can ensure that enough history is held to provide details since the last manual wheel assembly maintenance operation, so that the history can be transferred for use in trend analysis, along with the current measurement data. Longer periods of history may also be kept.
In some examples the sensor controller 412 is configured to operate the wireless communications interface 412 to send control signals to a remote indicating device, for example located at a position on the vehicle which is visible from the outside of the vehicle. Alternatively the remote indicating device may be a mobile device configured to be used by an operator to periodically interrogate the sensor controller 412. The remote indicating device may be configured to provide information about the condition of the wheel assembly to maintenance crews, and may use any suitable indicating technology to provide the indication.
In some examples the sensor controller 412 is configured to operate the wireless communications interface 414 to communicate data with other sensor apparatus mounted on other wheel assemblies of the same vehicle. In such examples, one sensor apparatus of the set of sensor apparatus installed on the vehicle may be configured to collate data from all of the sensor apparatus and to send a control signal based on the collated data to a single remote indicating device. For example, if any of the measurement data acquired by any of the sensor apparatus indicates that maintenance of a wheel assembly is required, the control signal may cause the indicating device to indicate that maintenance is required. Such an arrangement reduces the need for an operator to check each wheel assembly individually.
In some examples the sensor controller 412 may be configured to operate the wireless communications interface 414 to communicate data with a further system of a vehicle in which the wheel assembly is comprised. Where the vehicle is an aircraft, for example, such a further system may be a cockpit system for providing information to flight crew, or an avionics system.
The sensor controller 412 may be configured to operate, at any given time, the other components of the sensor device 10 according to a predefined measurement protocol. The sensor controller 412 may be pre-programmed with a set of two or more measurement protocols, and may be configured to select a particular measurement protocol to use at a given time. The predefined measurement protocols are stored in the memory unit of the sensor controller 412. The sensor controller 412 may be configured to select a particular measurement protocol based on any one or more of: a command signal received by the sensor controller 412 (e.g. from a remote system); a relative rotation state of the sensor device and the wheel (which may be a current relative rotation state or a predicted future relative rotation state); a parameter relating to the operation of a vehicle on which the sensor device 10 is installed. Such a parameter relating to the operation state of a vehicle may be, for example, flight phase (if the vehicle is an aircraft); speed; altitude; or the like.
One or more of the predefined measurement protocols may only be suitable for use when there is relative circumferential movement between the sensor device 10 and the wheel 13, in which case the sensor controller 412 may be configured to select such a measurement protocol only when it has determined (e.g. based on measurement data received from the movement detector 416) that relative movement is occurring at the current time. For example, at least one of the predefined measurement protocols pre-programmed onto the sensor controller 412 may be a scanning measurement protocol which requires the sensor controller 412 to operate the distance sensor 415 according to the scanning mode described above. Other of the predefined measurement protocols may require no relative movement of the sensor device 10 and wheel 13 to be occurring, or may not care whether or not relative movement is occurring. For example, for some of the types of measurement data able to be acquired by the sensor device 10 (such as pressure and temperature) it is irrelevant whether there is relative movement between the sensor device 10 and the wheel 13.
The set of pre-programmed measurement protocols may include a damage measurement protocol. An example damage measurement protocol comprises emitting radiation such that it is incident on a substantially full width of an inner surface of a tire mounted on the wheel, and detecting reflections of the emitted radiation from the substantially full width of the inner surface of the tire, continuously over a time period in which the sensor device moves around at least a full circumference relative to the wheel. The damage measurement protocol is therefore a scanning measurement protocol.
Each of the beams 11a-e of radiation is substantially identical all respects, except for the direction of emission. The properties of the beams 11a-e are selected such that a significant part of each beam is reflected at an outer wall of the tire 14. The emitted radiation may be reflected by an interface between the tire material and the surrounding air, and/or may be reflected by an interface between the tire material and the ground 16. At least some of the radiation which is reflected at the outer wall of the tire 14 is detected by the distance sensor 415. The signal detected by the distance sensor 415 will be altered if the outer wall of the tire 14 within the region from which the detected reflections originate is damaged in any way (for example if a cut is present). The sensor controller 412 is programmed with appropriate signal analysis algorithms to determine whether damage is present based on the detected signal, and is configured to use these algorithms when operating according to the damage detection measurement protocol.
The tire 14 optionally comprises a portion of reflective material 51 arranged to make any damage to the tire easier to detect based on the detected reflections. For example, such a portion of reflective material may comprise a continuous coating on the outer surface of the tire 14, which is configured to become discontinuous if the tire experiences damage. Alternatively the portion of reflective material 51 could be embedded in the tire material, as is the case in
The damage measurement protocol is a scanning measurement protocol, meaning that the controller 412 is configured to implement it only when there is relative circumferential movement between the sensor device 10 and the wheel 13. The time period during which the radiation is emitted according to the damage measurement protocol is preferably long enough for measurement data covering a continuous complete circumference of the tire 14 to be acquired. The length of the time period therefore depends on the rate of relative circumferential movement of the sensor device 10 and wheel 13, and on whether the radiation is emitted as a single long pulse or a series of discrete pulses, as described above. The controller 412 may be configured to determine a length for the time period based on at least these factors. Alternatively the controller 412 may be configured to cause the distance sensor 415 to emit the radiation for as long as relative movement between the sensor device 10 and wheel 13 is occurring.
The set of pre-programmed measurement protocols may include a tread depth measurement protocol. An example tread depth measurement protocol comprises emitting the first beam 11 of radiation such that it is incident on the inner circumferential surface 141 of the tire and detecting reflections of the first beam 11 from the inner circumferential surface 141; and emitting the second beam of radiation 12 such that it is incident on the ground 16 and detecting reflections of the second beam 12 from the ground 16. The tread depth measurement protocol may be implemented either as a scanning measurement protocol (if there is relative rotation between the sensor device 10 and wheel 13 at the time of implementing the tread depth measurement protocol), or as a static measurement protocol (if there is no relative rotation between the sensor device 10 and wheel 13 at the time of implementing the tread depth measurement protocol).
The tread depth measurement protocol may be implemented using either the beam arrangement shown in
The first beam 11 is configured such that it will be at least partly reflected from a reference surface of the tire 14. In the
The sensor controller 412 is configured to determine a shortest distance dR between the sensor device 10 and the reference surface 141, 27 based on the first reflections, and to determine a shortest distance dG between the sensor device 10 and the ground 16 based on the second reflections, in the manner described above in relation to
If the tread depth measurement protocol is implemented as a scanning measurement protocol, then measurement data covering an entire circumference of the tire 14 is acquired, during a period in which there is relative circumferential movement between the sensor device 10 and the wheel 13, in the manner described above in relation to the tire damage measurement protocol. It may be advantageous to determine current TD for an entire circumference of the tire 14 because it is possible for the tire 14 to wear unevenly, such that the current TD at a first circumferential location is acceptable according to the predefined threshold whilst the current TD at a second, different circumferential location is unacceptable.
If the tread depth measurement protocol is implemented as a static measurement protocol, at a time when there is no relative circumferential movement between the sensor device 10 and the wheel 13, then a current value of TD can be determined only in respect of the circumferential location of the tire 14 on which the first and second beams 11, 12 are incident at the time of implementing the tread depth measurement protocol. A static tread depth measurement protocol may be suitable for applications where the tire 14 is expected to wear very evenly, such that TD is not expected to vary significantly with circumferential location.
The tread depth measurement protocol may also be used to detect “flat spots” on a tire. Such flat spots are local deformations of the tire tread, which may occur for example as a result of skidding or wheel lock.
The set of pre-programmed measurement protocols may include a load measurement protocol. An example load measurement protocol comprises emitting radiation such that it is incident on a reference circumferential surface of a tire having a known distance from an inner circumferential surface of the tire, and detecting reflections of the emitted radiation from the reference circumferential surface of the tire. The reference circumferential surface may have any of the features of the example reference surfaces discussed above. The load measurement protocol may be performed at any time when the wheel assembly is supporting the vehicle, regardless of whether relative movement between the sensor device 10 and the wheel 13 is occurring.
The load measurement protocol may be implemented using a single beam 11 of radiation, as shown in
The distance between the sensor device 10 and the reference surface 27 varies in dependence on the vertical load on the wheel assembly 2 (which depends on the weight of the vehicle being supported by the wheel assembly 2, as well as the properties of the gas in the space 15 inside the tire). For a given set of tire gas properties, when the vehicle is heavier, the load is greater and the tire 24 deforms (squashes) more such that the distance between the sensor device 10 and the reference surface 27 reduces. In other words, the distance between the sensor device 10 and the reference surface 27 is inversely proportional to the load, enabling the load to be calculated based on a measurement of the distance between the sensor device 10 and the reference surface 27, if the gas properties are known. Part (i) of
As mentioned above, he amount of deformation experienced by the tire 24 in response to a given vertical load depends on the properties (i.e. temperature and pressure) of the gas in the space 15 inside the tire 24. More deformation will be experienced for a given change in load if the tire pressure is relatively lower. The sensor controller 412 is therefore configured to calculate the load on the wheel assembly 2 additionally based on the tire pressure at the time at which the distance between the sensor device 10 and the reference surface 27 was measured. In some examples the sensor controller 412 is configured to receive current tire pressure information from a further system, such as a dedicated tire pressure monitoring system of the vehicle. In examples in which the sensor device comprises the pressure sensor 418 the load measurement protocol may comprise measuring tire pressure using the pressure sensor 418 substantially simultaneously with emitting the radiation (with the distance sensor 415) to measure the distance between the sensor device 10 and the reference surface 27.
The sensor controller 412 may calculate the load on the wheel assembly using any suitable technique. For example, the sensor controller 412 may store a look-up table of distances, tire pressures and loads in its memory, and may calculate the load based on this look-up table. Alternatively the sensor controller 412 may be pre-programmed with an algorithm configured to calculate a load using a current distance value and a current tire pressure value.
In some applications each wheel assembly of the vehicle will comprise a sensor device 10, meaning that a load can be calculated for each wheel assembly. In some examples the sensor controller 412 is configured to transmit a calculated load value which results from implementing the load measurement protocol to a further system (such as an aircraft avionics system). The further system may receive a load value for each wheel assembly of the vehicle. The further system may be configured to use the received load values to calculate one or more overall vehicle parameters such as the total weight of the vehicle, the centre of gravity of the vehicle, or the like.
The sensor controller 412 may be configured to automatically implement the load measurement protocol in response to certain operational conditions of the vehicle being met, for example when an aircraft is ready for push back from a gate. Alternatively or additionally the sensor controller 412 may be configured to implement the load measurement protocol in response to a control signal received from a further system, such as a remote maintenance device or a cockpit control system. For example, a pilot of an aircraft may trigger implementation of the load measurement protocol when an aircraft is ready for push back, to check that its weight and/or weight distribution is within acceptable limits.
A first block 901 comprises providing a distance sensor in an enclosed space formed by a wheel of the vehicle and a tire mounted on the wheel. The sensor may be comprised in a sensor device according to the invention. The distance sensor may be, for example, the distance sensor 415 described above. Providing the distance sensor may comprise attaching the distance sensor to the wheel, in any of the manners described above. In some examples providing the distance sensor comprises attaching the distance sensor to the wheel such that it is able to move around the circumference of wheel. Block 901 may be performed during manufacture of the wheel assembly, and/or during a maintenance of the wheel assembly. Block 901 may be performed, for example, during a process of installing a tire on the wheel. Block 901 may be performed manually by an operator.
A second block 902 comprises performing a distance measurement using the distance sensor. The distance measured is a distance between the sensor and an object remote from the sensor, which may be any of the example objects discussed above. The distance measurement may be performed in any of the manners described above in relation to the example distance sensor 415. Performing the distance measurement may comprise measuring a first distance and a second, different distance. The distance measurement is performed when the sensor is disposed at a first circumferential location relative to the wheel. The first circumferential location may be any location on the circumference of the wheel. Block 902 may be performed automatically as a result of instructions pre-programmed onto the distance sensor or onto a different component of a sensor device in which the distance sensor is comprised. Block 902 may be performed in response to the distance sensor or a sensor device in which the distance sensor is comprised receiving a control signal configured to trigger performance of block 902 from a further system.
A third block 903 comprises determining a value of the operational parameter based on the measured distance. The operational parameter may be a parameter of a wheel assembly in which the wheel and tire are comprised, or of a vehicle in which such a wheel assembly is comprised. The operational parameter may be, for example, tire tread depth, tire condition, wheel assembly load, vehicle weight, vehicle centre of gravity or the like. The operational parameter may be determined in any of the manners described above. The operational parameter may be determined based on the measured distance in combination with one or more further measured or predicted values.
In some examples of the method 900 (such as examples in which the distance sensor is fixedly attached to the wheel and/or examples in which the distance sensor is being used to implement a static measurement protocol), the method 900 is complete when the performance of block 903 is complete.
In other examples (such as examples in which the distance sensor is movably attached to the wheel and is being used to implement a scanning measurement protocol) the method 900 comprises an optional fourth block 904. In block 904 a further distance measurement is performed when the sensor is disposed at a second, different circumferential location relative to the wheel. Block 904 is implementable by sensor devices which are attached to the wheel such that relative circumferential movement between the sensor device and the wheel is permitted.
The further distance measurement is of the same distance or distances as the first distance measurement and is performed in the same manner as the first distance measurement. The second circumferential location may be separated from the first circumferential location, or it may be adjacent to the first circumferential location. The sensor may be at substantially the same location relative to a vehicle in which the wheel and tire are comprised during the performance of the distance measurement and during the performance of the further distance measurement.
Between performing the distance measurement and performing the further distance measurement the wheel is rotated about its axis. The amount by which the wheel is rotated corresponds to the circumferential separation of the first and second circumferential locations. The wheel (and therefore a vehicle in which the wheel is comprised) may undergo translational movement between the performance of the distance measurement and the performance of the further distance measurement. The amount of the translational movement may correspond to the amount by which the wheel is rotated between the performance of the distance measurement and the performance of the further distance measurement. The rotation of the wheel may be as a result of the normal operation of a wheel assembly in which the wheel is comprised to support and/or drive movement of the vehicle.
The change in the relative circumferential position of the distance sensor and the wheel occurs because the distance sensor experiences substantially no rotational movement when the wheel rotates between the performance of the distance measurement and the performance of the further distance measurement. This is because the distance sensor is free to move circumferentially around the wheel, and because the force of gravity acting on the sensor acts to resists movement of the sensor away from its lowest possible position (that is, the position closest to the ground).
The rotation of the wheel which occurs between the performance of the distance measurement and the performance of the further distance measurement is at a sufficiently low rate that the centrifugal force on the distance sensor does not overcome the force of gravity on the sensor. In examples of the method 900 which include optional block 904, the wheel may rotate continuously during performance of the method 900, at a sufficiently low rate that the centrifugal force on the sensor does not overcome the force of gravity on the sensor.
Examples of the method 900 which include optional block 904 may comprise performing a series of distance measurements, the series including the distance measurement and the further distance measurement. In such examples each distance measurement of the series is performed when the sensor is at a different circumferential location relative to the wheel. The different circumferential locations are distributed around the circumference of the wheel. In some examples the different circumferential locations may be substantially evenly distributed around the circumference of the wheel. In some examples the circumferential separation between each of the different circumferential locations is small enough that substantially all of the circumference of the wheel is covered by the series of distance measurements. Examples of the method 900 which comprise performing a series of distance measurements may be completed once distance measurements have been acquired which cover substantially all of the circumference of the wheel. The method 900 may comprise repeatedly performing the series of measurements for as long as the wheel is rotating at a sufficiently low speed. The method 900 may comprise repeatedly performing the series of measurements until the sensor receives a control signal configured to stop the sensor from performing measurements.
Although the invention has been described above with reference to one or more preferred examples or embodiments, it will be appreciated that various changes or modifications may be made without departing from the scope of the invention as defined in the appended claims.
Although the invention has been described above mainly in the context of a fixed-wing aircraft application, it may also be advantageously applied to various other applications, including but not limited to applications on vehicles such as helicopters, drones, trains, automobiles and spacecraft.
Where the term “or” has been used in the preceding description, this term should be understood to mean “and/or”, except where explicitly stated otherwise.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019869.3 | Dec 2020 | GB | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/086082 | 12/16/2021 | WO |
