Vehicle brake device and method for a vehicle brake device

Abstract

Vehicle braking is disclosed. In one aspect, apparatus having a processor configured to determine a number of future usage cycles of an aircraft wheel brake based on a predicted condition of the brake and methods for determining a number of future usage cycles of an aircraft wheel brake based on a predicted condition of the brake are disclosed. An aircraft including one or more aircraft wheel brakes and an apparatus is also disclosed.

Description

Technical Field

[0001] This invention relates to vehicle braking. In particular, but not exclusively, this invention relates to determining the number of future service cycles of vehicle wheel brakes, such as aircraft wheel brakes. Background Technology

[0002] The condition of an aircraft wheel brake can change with use. For example, the brake may wear down. Eventually, the condition of the brake may change to the point where it may require repair or replacement of the brake or its components. Summary of the Invention

[0003] A first aspect of the invention provides an apparatus including a processor configured to determine the number of future use cycles of an aircraft wheel brake based on predicted brake conditions.

[0004] Optionally, the predicted condition is the predicted future condition of the brake.

[0005] Optionally, the predicted condition includes the predicted oxidation state of the brake.

[0006] Optionally, an oxidation model can be used to predict the oxidation state after the braking event based on the initial thermal oxidation state before the braking event and the temperature profile of the brake relative to time.

[0007] Optionally, the processor is configured to determine the number of future use cycles by predicting the number of future use cycles required to reach the oxidation threshold based on the predicted oxidation state.

[0008] Optionally, the predicted condition includes the predicted wear condition of the brake.

[0009] Optionally, the processor is configured to determine the number of future use cycles by predicting the number of future use cycles required to reach the wear threshold based on the predicted wear state.

[0010] Optionally, the processor is configured to determine the wear relationship between the wear state of the brake and the number of service cycles of the brake; and to determine the predicted wear state based on the wear relationship.

[0011] Optionally, the processor is configured to determine wear relationships based on one or more measured wear values.

[0012] Optionally, the predicted condition of the brake includes a predicted brake length value, which is determined based on the wear condition of the brake and the oxidation length of the brake, with the oxidation length determined based on the oxidation condition of the brake.

[0013] Optionally, the processor is configured to determine the oxidation length based on factors such as the oxidation state of the brake, the area of ​​the brake disc, and the amount of mass loss indicated by the original density of the brake.

[0014] Optionally, the processor is configured to determine the predicted brake length value by subtracting the oxidation length from the wear value.

[0015] Optionally, the processor is configured to determine the number of future use cycles by predicting the number of future use cycles required to reach the predicted brake length threshold.

[0016] Optionally, the processor is configured to determine a brake length relationship between the brake length value and the number of brake usage cycles; and to determine a predicted brake length value based on the brake length relationship.

[0017] Optionally, the processor is configured to compare the predicted condition of the brake with the condition of the brake determined based on one or more measurement characteristics of the brake.

[0018] Optionally, the processor is configured to determine whether the brake alarm criteria are met based on comparison; and to provide an indication that the brake alarm criteria are met.

[0019] A second aspect of the invention provides an aircraft including one or more aircraft wheel brakes; and a device according to the first aspect.

[0020] A third aspect of the invention provides a method comprising: determining the number of future service cycles of an aircraft wheel brake based on a predicted condition of the brake.

[0021] Alternatively, in the method according to the third aspect, the predicted state is the predicted future state of the brake.

[0022] Optionally, in the method according to the third aspect, the predicted condition includes the predicted oxidation state of the brake.

[0023] Alternatively, in the method according to the third aspect, an oxidation model is used to predict the oxidation state after the braking event based on the initial thermal oxidation state before the braking event and the temperature curve of the brake relative to time.

[0024] Optionally, the method according to the third aspect includes: determining the number of future use cycles by predicting the number of future use cycles required to reach the oxidation threshold of the predicted oxidation state.

[0025] Optionally, in the method according to the third aspect, the predicted condition includes the predicted wear condition of the brake.

[0026] Optionally, the method according to the third aspect includes: determining the number of future service cycles by predicting the number of future service cycles required for the predicted wear condition to reach the oxidation threshold.

[0027] Optionally, the method according to the third aspect includes: determining the wear condition of the brake and the number of service cycles of the brake; and determining the predicted wear condition based on the wear relationship.

[0028] Optionally, the method according to the third aspect includes determining the wear relationship based on one or more measured wear values.

[0029] Optionally, in the method according to the third aspect, the predicted condition of the brake includes a predicted brake length value, which is determined based on the wear condition of the brake and the oxidation length of the brake, the oxidation length being determined based on the oxidation condition of the brake.

[0030] Optionally, the method according to the third aspect includes determining the oxidation length based on factors such as the oxidation state of the brake, the area of ​​the brake disc, and the amount of mass loss indicated by the original density of the brake.

[0031] Optionally, the method according to the third aspect includes: determining the number of future use cycles by predicting the number of future use cycles required for the predicted brake length value to reach the brake length threshold.

[0032] Optionally, the method according to the third aspect includes: determining a brake length relationship between the brake length value and the number of brake usage cycles; and determining a predicted brake length value based on the brake length relationship.

[0033] Optionally, the method according to the third aspect includes: comparing the predicted condition of the brake with the condition of the brake determined based on one or more measurement characteristics of the brake.

[0034] Optionally, the method according to the third aspect includes: determining whether the brake alarm criteria are met based on comparison; and providing an indication that the brake alarm criteria are met. Attached Figure Description

[0035] Various embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, in which:

[0036] Figure 1 It is a schematic diagram depicting an example aircraft that can be deployed on it;

[0037] Figure 2 It is a schematic diagram depicting an aircraft wheel brake and an aircraft landing gear wheel according to an example;

[0038] Figure 3 This is a schematic diagram based on the example device;

[0039] Figure 4 This is a first graph illustrating the condition of an aircraft wheel brake as a function of the number of brake usage cycles, based on an example.

[0040] Figure 5 This is a schematic diagram of the brake disc of an aircraft wheel brake, based on the example.

[0041] Figure 6 This is a second graph illustrating the state of the brake as a function of the number of brake usage cycles, based on an example.

[0042] Figure 7 This is a flowchart of an exemplary method for determining the thermal oxidation state of the brakes of an aircraft landing gear;

[0043] Figure 8 This is a flowchart of an exemplary method for determining the thermal oxidation state of the brakes of an aircraft landing gear;

[0044] Figure 9 This is an exemplary graph illustrating the temperature of the brake relative to time;

[0045] Figure 10 This is an exemplary graph illustrating the thermal oxidation state of a brake over time at a specific temperature.

[0046] Figure 11 This is an exemplary flowchart of a method for determining brake wear based on an example; and

[0047] Figure 12 This is an exemplary flowchart based on an example of a method for predicting the number of good future usage cycles of an aircraft brake. Detailed Implementation

[0048] The following disclosure relates to a system and process for determining the number of future service cycles of aircraft wheel brakes.

[0049] Figure 1This is a simplified schematic diagram of aircraft 100. Aircraft 100 includes multiple landing gear assemblies 102. The landing gear assemblies may include main landing gear and nose landing gear that can extend during takeoff and landing. Each landing gear assembly 102 includes wheels, such as wheels 104. Aircraft 100 includes a computing system 106, which may include, for example, one or more processors and one or more computer-readable storage media. Aircraft 100 may also include devices 108, such as instruments or sensors for measuring aircraft-related characteristics or parameters, and instruments or sensors for measuring environmental characteristics. It should be understood that in some examples, devices 108 may be distributed at various different locations within aircraft 100. Aircraft 100 may also include indication devices 110 for providing various aircraft-related indications, examples of which will be described below. Indication devices may include screens displaying text and / or graphs, dials, light indicators, sound indicators that transmit sound to provide indications, etc.

[0050] Figure 2 This is a simplified schematic diagram of an aircraft wheel brake 200 (hereinafter referred to as "brake" 200) associated with the wheels 104 of aircraft 100. Each wheel of aircraft 100 may have a brake, such as the brake 200 associated with the wheel. The brake 200 applies braking force to inhibit the rotation of the wheel 104. In this example, the brake 200 includes multiple brake discs 202, each including a pressure plate 204, a reaction plate 206, and multiple rotors and stators, such as rotors 208 and stators 210. In this example, the brake discs 202 include multiple rotors and stators, therefore the brake assembly 200 is a multi-disc brake. In other examples, the brake assembly 200 may not be a multi-disc brake. It should be understood that the type of brake used in aircraft landing gear depends on the characteristics of the aircraft under discussion, such as size, load capacity, etc.

[0051] As the aircraft 100 travels along the ground supported by the landing gear 102, the rotor rotates with the wheel 104, while the stator, pressure plate 204, and reaction plate 206 do not rotate with the wheel 104. When braking is applied, the pressure plate 204 pushes towards the reaction plate 206, causing the brake discs 202 to contact each other (e.g., Figure 2 (As shown in box 212) and friction acts to suppress the rotational motion of the rotor, thereby generating braking force to reduce the speed of the aircraft 100. The brake 200 may be hydraulically actuated or electrically actuated.

[0052] Any or more of the rotor, stator, pressure plate 204, and reaction plate 206 may be made of a carbon-carbon (CC) composite. A brake including a brake disc made of a CC composite may be referred to as a carbon brake. For example, brake disc 202 may be made of a graphite matrix reinforced with carbon fibers. During use, brake disc 202 may undergo oxidation. During the oxidation reaction, oxygen reacts with the carbon in brake disc 202, resulting in the removal of carbon atoms from brake disc 202 due to the production of carbon dioxide and / or carbon monoxide, thus causing a mass loss. The oxidation state / level of brake 200 can be expressed as the amount of mass loss due to oxidation.

[0053] Brake disc 202 can be oxidized by catalytic oxidation or thermal oxidation. Catalytic oxidation can occur when the oxidation reaction is aided by a catalyst. For example, alkali metals are known catalysts for the oxidation of CC compounds. Catalytic oxidation may be associated with areas in the air with relatively high salinity. Catalytic oxidation may also be associated with airports using runway de-icing systems containing alkali salts. Thermal oxidation of brake disc 202 may occur if it reaches high temperatures. During use, brake 200, and particularly brake disc 202, may reach high temperatures. This is because when brake 200 is applied to reduce the speed of aircraft 100, some of the kinetic energy of aircraft 100 is absorbed as heat into brake 200, resulting in an increase in brake temperature. In this example, the component of brake 200 composed of CC compounds (i.e., brake disc 202) is oxidized. However, the present disclosure below relates to the oxidized state of brake 200.

[0054] Brake disc 202 may be subject to wear due to friction during braking. For example, when a given brake disc comes into contact with another brake disc, the material on the surface of the given brake disc may be lost due to the action of friction during braking. Wear may result in wear on brake disc 202 ( Figure 2 The length L (shown in the diagram) decreases. In this example, the brake disc 202 is worn. However, the present disclosure below relates to the wear condition of the brake 200.

[0055] Figure 3 This is a simplified schematic diagram of the device 300 as shown in the example. Device 300 includes a processor 302. Processor 302 is configured to determine the number of future usage cycles of brake 200 based on predicted conditions of brake 200. The usage cycle of brake 200 can be the time from when the aircraft 100, on which brake 200 is mounted, is at the boarding gate before flight to when it is at the arrival gate after flight. For example, the usage cycle includes all use of brake 200 in relation to a specific flight performed by aircraft 100.

[0056] The number of future service cycles for brake 200 refers to the number of additional service cycles during which brake 200 is permitted to be used. The term "future service cycle" as used herein refers to service cycles of brake 200 that have not yet occurred. For example, brake 200 may be permitted to be used as long as brake 200 is in a condition considered good and safe. As brake 200 is used, its condition can change until it is in a condition that is not considered good or safe. For example, if brake 200 is worn and / or oxidized beyond a certain state described in further detail below, brake 200 may be in a condition that is not considered good. When brake 200 reaches or approaches a condition that is not considered good, repair or replacement of brake 200 or its components can be planned and implemented. This ensures the safe operation of aircraft 100.

[0057] The predicted condition may include the predicted oxidation state of brake 200. Alternatively, or additionally, the predicted condition may include the predicted wear state of brake 200. In some examples, the predicted condition may be the predicted future condition of brake 200 as described below.

[0058] The predicted oxidation state of brake 200 can be the predicted thermal oxidation state of brake 200. However, in some examples, the predicted oxidation state may also take catalytic oxidation into account.

[0059] In some examples, the methods and systems described in a previously unpublished application, GB patent application number 1803203.7, attached herein by reference, can be used to determine the predicted thermal oxidation state of brake 200. For example, the thermal oxidation state after a braking event can be predicted using an oxidation model based on an initial thermal oxidation state prior to the braking event and a temperature profile of brake 200 over time. Processor 302 can receive the predicted thermal oxidation state of brake 200 from the device used to determine it. Alternatively, up-to-date information regarding the predicted thermal oxidation state of brake 200 can be stored in a computer-readable storage medium (e.g., a computer-readable storage medium as part of computing system 106), and first controller 302 can retrieve the predicted thermal oxidation state of brake 200 from said computer-readable storage medium. First controller 302 can retrieve the predicted thermal oxidation state of brake 200 whenever it is updated. In some examples, processor 302 can predict the thermal oxidation state of brake 200 itself as described in a previously unpublished application.

[0060] The temperature sensor 218 associated with brake 200 (see...) can be detected from... Figure 2 The temperature profile is obtained. Temperature sensor 218 can be configured to make thermal contact with one of the brake discs. Figure 2 In this example, temperature sensor 218 is disposed on stator 210. In this example, stator 210 is the brake disc that may reach the highest temperature. Temperature sensor 218 can be any type of temperature sensor suitable for use in aircraft brake assemblies. For example, temperature sensor 218 can operate normally within the temperature range that brake disc 202 may reach. For example, temperature sensor 218 can be a thermocouple, surface acoustic wave (SAW) sensor, eddy current sensor, resistive thermal sensor, strain gauge, etc. If the temperature sensor is disposed on a portion of brake 200 other than on one of the brake discs 202, the temperature of brake disc 202 can be determined using an indication of the relationship between the temperature measured by said temperature sensor and the temperature of brake disc 202. In some examples, the indication of the relationship can be determined experimentally. In some examples, a brake thermal model can be used to determine the indication of the relationship.

[0061] Temperature sensor 218 can measure the temperature of stator 210 at given measurement intervals during the expected period of use of brake 200. The duration of the given measurement interval can vary. The given measurement interval can be regular, irregular, or regular for one period and irregular for another. For example, temperature sensor 218 can measure the temperature such that the temperature distribution of stator 210 is captured relative to time. In other words, temperature sensor 218 measures the temperature of stator 210 at given measurement intervals such that temperature information is captured as a function of time. For example, the processor of computing system 106 can control the operation of temperature sensor 218 based on instructions stored in a computer-readable storage medium of computing system 106. The temperature measurements captured by temperature sensor 218 can be stored, for example, in the storage medium of computing system 106 along with associated time data.

[0062] The predicted thermal oxidation state can be the currently predicted thermal oxidation state of brake 200. In other words, the predicted thermal oxidation state can include the predicted current thermal oxidation state of brake 200. For example, the current thermal oxidation state can be predicted based on temperature measurements from temperature sensor 218. The number of future service cycles of brake 200 can be predicted based on the predicted current thermal oxidation state of brake 200. For example, the earlier the current thermal oxidation state is predicted, the fewer the number of future service cycles of brake 200 will be.

[0063] In some examples, the predicted thermal oxidation state can be the predicted future thermal oxidation state of brake 200. For a given future usage cycle, the predicted future thermal oxidation state of brake 200 can be determined based on the predicted temperature profile of brake 200 for that given future usage cycle and taking into account the thermal oxidation states of all previous usage cycles. It should be understood that, in addition to using the predicted temperature profile, the predicted future thermal oxidation state can also be determined in the same manner as the predicted current thermal oxidation state for usage cycles that have already occurred. The predicted temperature profile can be based on the temperature profile of usage cycles that have already occurred. In some examples, a predetermined predicted temperature profile can be used. The predetermined predicted temperature profile can be, for example, stored in and retrieved from a computer-readable storage medium of computing system 106. The predicted temperature profile can depend on the predicted route of aircraft 100, the characteristics of the airport to which aircraft 100 is about to fly and depart, etc. The method described in the aforementioned undisclosed application can be used to determine the predicted future thermal oxidation state.

[0064] The number of future service cycles can be determined by predicting the number of future service cycles required for the predicted oxidation state to reach the oxidation threshold. For example, the number of future service cycles can be determined by predicting the number of future service cycles required for the predicted future thermal oxidation state to reach the oxidation threshold.

[0065] The predicted (current or future) thermal oxidation state can be expressed as the amount of mass loss due to thermal oxidation (e.g., as a percentage of the original mass of brake 200). The oxidation threshold can also be expressed as the amount of mass loss. In some examples, the oxidation threshold can be 4% to 6.5% of the original mass loss of brake 200. For example, the oxidation threshold could be 5.7% of the original mass of brake 200 lost due to oxidation. The oxidation threshold can be part of a criterion used to determine whether brake 200 is in good or safe condition or requires repair or replacement.

[0066] Processor 302 can determine at least the number of future service cycles required for the predicted future thermal oxidation state to reach an oxidation threshold. In some examples, if the predicted future thermal oxidation state is equal to or exceeds the oxidation threshold in the next service cycle after a given number of future service cycles, then the oxidation threshold can be considered to have been reached after the given number of future service cycles. In these examples, the given number of future service cycles can be the number of future service cycles of brake 200 before the entire brake 200 or a portion of the brake requires maintenance or replacement.

[0067] As described, in some examples, the predicted oxidation state may also take into account catalytic oxidation. For example, the predicted oxidation state may be determined by considering the amount of time that aircraft 100 spends in areas where the air has relatively high salinity and / or at airports using runway de-icing equipment containing alkaline salts. In these examples, the predicted future oxidation state may take into account the amount of time that aircraft 100 is expected to spend at these locations for an additional usage cycle.

[0068] Alternatively, or in addition to including the predicted oxidation state of brake 200, the predicted condition may also include the predicted wear state of brake 200. The predicted wear state can be the wear state of brake 200 predicted after future use cycles of brake 200 have already occurred. The wear state of brake 200 (i.e., the actual wear state) can be determined using measured wear values. The measured wear value can be a measured length associated with brake 200. For example, the measured wear value can be the length L of brake disc 202 (see...). Figure 2 The measured wear value provides an indication of the change in length L. In the case where the brake 200 is electrically actuated and controlled by an electronic brake controller, the measured wear value can be the length L of the brake disc 202 measured by the electronic brake controller. The electronic brake controller can, for example, control the position of the pressure plate 204 relative to the reaction plate 206, and thus be able to measure the length L.

[0069] When the brake 200 is hydraulically actuated, a brake wear sensor 216 configured to measure wear values ​​can be provided. The brake wear sensor 216 may include a linear variable differential transformer (LVDC) sensor or a Hall effect sensor configured to measure the linear displacement of components of the brake 200. For example, such a brake wear sensor 216 can measure the linear displacement of the pressure plate 204 when the brake 200 is fully applied and can obtain the length L from the measured linear displacement.

[0070] In some examples, for instance, the measured wear value may be the remaining length of a wear pin (not shown) associated with brake 200. The wear pin may be a component that provides an indication of a change in the length L of brake disc 202. For example, a reduction in the remaining length of the wear pin may correspond to a reduction in the length L of brake disc 202. The remaining length of the wear pin may be the length of the wear pin extending from a component of brake 200. For example, the remaining length of the wear pin may be the length of the wear pin extending from a surface of the piston housing of brake 200 or another surface of the housing of brake 200.

[0071] The wear pin can move with the brake disc 202 relative to a surface from which the remaining length of the wear pin is measured. The wear sensor 216 can be a sensor fixed relative to the surface from which the remaining length of the wear pin is measured. Such a sensor can measure the position of the wear pin relative to said surface and therefore can measure the change in the remaining length of the wear pin.

[0072] The wear condition of brake 200 can be represented by measured wear values, such as the remaining length of the worn pin as measured by brake wear sensor 216. As described, the length L of brake disc 202 decreases as brake 200 wears more. Therefore, the measured wear value, as defined herein, decreases with the occurrence of usage cycles. The predicted wear condition can be represented by a predicted wear value, which can be a predicted length related to brake 200, such as the predicted remaining length of the worn pin. In the examples described below, the actual wear condition and the predicted wear condition are represented by the measured wear value and the predicted wear value, which decrease as brake 200 wears more.

[0073] In an example where the predicted condition includes the predicted wear state of brake 200, the predicted wear state can be determined based on the wear state of brake 200. For example, processor 302 can be configured to determine a wear relationship between the wear state of brake 200 and the number of use cycles. Processor 302 can be configured to determine the predicted wear state based on the wear relationship described below. Processor 302 can be configured to determine the wear relationship based on one or more measured wear values. For example, the wear state can be measured with respect to the number of use cycles that have occurred and taken into account with respect to the total number of use cycles that have occurred for brake 200. In the example described below, the wear state is measured for each use cycle that has occurred.

[0074] Figure 4 It is a graph illustrating the wear condition based on the example and the predicted wear condition as a function of the number of service cycles of the brake 200. Figure 4 The vertical axis of the graph represents the wear value (measured or predicted), while the horizontal axis represents the number of usage cycles. In this example, one hundred usage cycles have occurred (i.e., aircraft 100 has made 100 flights with brake 200 installed). Therefore, for each of the usage cycles that have occurred, the wear condition value, as measured by brake wear sensor 216, is shown to the left of line 402. Line 402 is a vertical line that intersects the horizontal axis at 100 usage cycles. For convenience, the individual wear condition values ​​are not shown. Instead, a solid line 404a fitted to the wear condition values ​​is shown.

[0075] The solid line 404a can be determined using any known data fitting method. For example, processor 302 can use simple linear regression analysis to determine the solid line 404a. Examples of other methods for fitting data include least squares, least absolute residuals, bivariate fitting, etc. It should be understood that any suitable data fitting method can be used.

[0076] In this example, a linear function is used to fit the wear state values ​​to generate a solid line 404a, which is a straight line. However, in some examples, different functions can be used. For example, a polynomial function, an exponential function, or another function that can describe the decrease in wear state values ​​as a function of the usage period can be used.

[0077] As described, linear functions in Figure 4 In the example, a linear function can be expressed according to the following equation 1:

[0078]

[0079] In the above equation (1), y represents the value of the wear state, x represents the number of use cycles, m represents the amount of brake wear per use cycle (i.e., the slope of the line fitted to the value of the wear state), and c represents the wear state when no use cycle occurs (i.e., the value of the wear value measured when no use cycle occurs - for example, this could be the initial length of the wear pin).

[0080] By fitting the wear state values, the values ​​of unknown parameters in the fitting function can be determined. In this example, the value of m can be determined by fitting the wear state values ​​using equation (1). The function used to fit the wear state values ​​and the parameters determined from the fitting represent the wear relationship.

[0081] To determine the predicted wear state after a given number of use cycles (i.e., the predicted wear state in this example), the given number of use cycles can be substituted as the value of parameter x into equation (1). Then, using the known parameter values ​​fitted from the right side of equation (1), the predicted wear state after the given number of use cycles (i.e., the value of parameter y when x equals the given number of use cycles) can be calculated. Figure 4 In the diagram, dashed line 404b represents the predicted wear condition as a function of the number of usage cycles. In other words, the line (i.e., dashed line 404b – based on the fitted function and determined parameters) can be determined for a number of usage cycles greater than the number of actual usage cycles. In this example, the predicted wear condition for the corresponding number of usage cycles is the value falling on dashed line 404b.

[0082] The number of future service cycles can be determined by predicting the number of future service cycles required for the predicted wear condition to reach the wear threshold. Figure 4 In the example, the wear threshold is represented by horizontal line 406. In this example, the wear threshold is reached at the number of usage cycles where the dashed line 404b intersects the horizontal line 406 representing the wear threshold (i.e., the number of usage cycles at which the predicted wear state reaches the wear threshold). The number of usage cycles at which the predicted wear state reaches the wear threshold is... Figure 4 This is represented by line 408. In some examples, if the predicted wear value equals or exceeds the wear threshold in the next usage cycle after a given number of future usage cycles, then the wear threshold can be considered to have been reached after a given number of future usage cycles. In this example, the wear threshold can be predicted to be reached after 2000 usage cycles.

[0083] Therefore, in this example, the number of future use cycles of brake 200 is... Figure 4 The number of service cycles between lines 402 and 408. In this example, the number of future service cycles of brake 200 needs to be 1,900 before any repair or replacement of the entire brake 200 or a portion of brake 200.

[0084] In the previously described example, the number of future service cycles of brake 200 is determined based on the predicted wear state or the predicted oxidation state of brake 200. The predicted wear state can be used in examples where brake 200 is expected to experience a relatively high amount of wear compared to the amount of thermal oxidation. This could be a situation where aircraft 100 is flying to and from airports with long runways and taxiways, where high-energy braking is not typically required, as high-energy braking would cause brake disc 202 to reach temperatures high enough for sufficient thermal oxidation. For example, this could be a situation where high-energy braking is not typically required at the airport to which aircraft 100 is flying, but where many braking applications are needed (e.g., at a busy airport with many aircraft landings and takeoffs). It should be understood that the amount of brake wear is related to the number of braking applications.

[0085] On the other hand, the predicted thermal oxidation state can be used in examples where the brake 200 is expected to undergo a relatively high amount of thermal oxidation compared to the amount of brake wear. This could be in the case of an aircraft 100 flying to an airport with a short runway that requires high-energy braking, resulting in the brake disc 202 reaching temperatures that cause significant thermal oxidation.

[0086] In some examples, the predicted condition of brake 200 may include a predicted oxidation state and a predicted wear state. In these examples, oxidation thresholds and wear thresholds may be used. For example, the number of future service cycles of brake 200 may be the number of future service cycles required for at least the predicted future thermal oxidation state to reach an oxidation threshold or the predicted wear state to reach a wear threshold.

[0087] For example, the number of future service cycles could be the number of future service cycles that reach either a wear threshold or an oxidation threshold. If the predicted wear condition reaches the wear threshold in fewer future service cycles, then the number of future service cycles is the number of future service cycles in which the wear condition will reach the wear threshold. On the other hand, if the predicted future thermal oxidation condition reaches the oxidation threshold in fewer future service cycles, then the number of future service cycles is the number of future service cycles in which the predicted future thermal oxidation condition will reach the oxidation threshold. In these examples, both the predicted wear condition and the predicted future thermal oxidation condition can be considered to determine the number of future service cycles for the brake 200.

[0088] In some examples, both brake wear and oxidation can be considered to determine the number of future use cycles in different ways. For example, the predicted condition of brake 200 may include a predicted brake length value. The predicted brake length value can be determined based on the wear condition of brake 200 and the oxidation length of brake 200. The oxidation length can be determined based on the oxidation condition of brake 200. Processor 302 can determine the predicted brake length value for use cycles that have already occurred. Processor 302 can also determine the predicted brake length value for future use cycles.

[0089] The oxidation length can be determined based on the amount of mass loss of the brake, as indicated by the corresponding oxidation state, the area of ​​the brake disc 202, and the original density of the brake 200. The oxidation length is a hypothetical length corresponding to the amount of material loss in the brake disc 202 due to oxidation. As described, the oxidation state can be the amount of mass lost by the brake 200 due to the oxidation reaction. It should be understood that oxidation, especially thermal oxidation, may not act uniformly on a specific surface of the brake disc but may occur at a certain depth within the brake disc in question. Therefore, oxidation may not necessarily lead to a change in the physical dimensions of the brake disc 202. However, the mass loss due to oxidation can be converted into a hypothetical oxidation length in the following manner.

[0090] It should be understood that the density of the brake disc 202 can change as mass is lost due to oxidation. However, for the purposes of this calculation, it is assumed that the density has not changed from the original density (before any oxidation occurs). Figure 5The brake disc 202 is schematically illustrated. For simplicity, individual brake discs such as rotor 208, stator 210, etc. are not shown; instead, all brake discs 202 are represented as a single cylindrical element. Figure 5 The surface area A of surface 502 shown can be known, for example, data provided by the manufacturer of brake 200 or data determined by measurement. The oxidation length can be determined according to equation (2).

[0091]

[0092] In equation (2), L ox It is the oxidation length, Δm ox The mass loss is due to oxidation, where A is the surface area of ​​surface 502 of brake disc 202 as described. This is the original density of the brake disc 202 (e.g., provided by the manufacturer of brake 200 or determined by measurement). Oxidation length L ox exist Figure 5 As shown in the image.

[0093] Although oxidation length L ox It is not the actual reduction in length L of the brake disc 202, but it provides a measurement of the oxidation state of the brake 200. Since the wear state of the brake 200 is represented by a reduction in length L, it is advantageous to also represent the oxidation state as length to assess the condition of the brake 200.

[0094] The predicted brake length can be determined by subtracting the oxidation length from the wear value. For example, for a given service life, the corresponding oxidation length L can be subtracted from the measured wear value. ox This allows us to obtain the corresponding brake length. The predicted brake length can therefore explain brake wear and oxidation of brake 200.

[0095] Processor 302 can determine the brake length relationship between the brake length value and the number of service cycles of brake 200. Processor 302 can determine the predicted brake length (i.e., for future service cycles) based on the brake length relationship. The brake length relationship can be determined in a manner similar to the wear relationship described above. Figure 6 It is a graph illustrating the wear condition, predicted wear condition, brake length, and predicted brake length based on the example. Figure 6 The vertical axis of the graph represents the length related to brake 200, which could be the measured wear value, the predicted wear value, the predicted brake length value, or the predicted future brake length value. The horizontal axis represents the number of use cycles. In this example, one hundred use cycles have occurred (as in...). Figure 4(In the example). The wear condition value measured by brake wear sensor 216 is shown to the left of line 402, which is a vertical line intersecting the horizontal axis at one hundred usage cycles. The solid line 404a above... Figure 4 The value in the middle represents the wear condition.

[0096] The predicted brake length, determined using the corresponding measured wear value and oxidation length (calculated from the corresponding predicted current thermal oxidation state), is also to the left of line 402. The solid line 604a below fits the predicted brake length value. The predicted brake length value can be fitted in a manner similar to the fitting described in relation to the wear state. For example, equation (1) can be used to fit the predicted brake length value. The function used to fit the predicted brake length value and the associated parameters determined from the fitting represent the brake length relationship. The predicted future brake length can be determined in the same manner as the predicted wear state. For example, the predicted wear value can be determined using a fitting of the brake length value as previously described in the context of the predicted wear state. Figure 6 In the diagram, the predicted brake length is represented by the dashed line 604b below.

[0097] In some examples using brake length, the predicted wear state, represented by the upper dashed line 404b, can be determined. The predicted wear state can be determined as previously described. Furthermore, in this example, the predicted oxidation state can also be determined as previously described. Thus, the predicted wear state and the predicted oxidation state can be used to determine a predicted brake length value (i.e., the value on the lower dashed line 604b) for future use cycles. For example, the predicted oxidation length for future use cycles can be determined from the corresponding predicted future thermal oxidation state and the predicted oxidation length can be subtracted from the predicted wear value to generate the lower dashed line 604b.

[0098] The predicted brake length value can be determined based on the minimum number of future service cycles required for the predicted brake length to reach a brake length threshold. The number of future service cycles for brake 200 can be determined by predicting the number of future service cycles required for the predicted brake length value to reach the brake length threshold. Figure 6In the example, the brake length threshold is represented by horizontal line 606. In some examples, the brake length threshold can be considered reached after a given number of future use cycles if the predicted brake length value becomes equal to or exceeds the brake length threshold in the next use cycle after a given number of future use cycles. The number of use cycles at which the predicted brake length value reaches the brake length threshold is represented by line 608. In this example, the brake length threshold is predicted to be reached after 1800 use cycles. Therefore, the number of future use cycles for the brake in this example is 1700. In this example, the brake length threshold is located below the wear threshold indicated by horizontal line 406. However, in other examples, the brake length threshold may be on the same horizontal line as the wear threshold.

[0099] Wear relationships and / or brake length relationships can be updated as future use cycles occur. For example, when more use cycles have occurred, wear relationships and / or brake length relationships can be updated to take into account the latest usage conditions.

[0100] In examples of determining wear relationships and / or brake length relationships, a certain number of usage cycles of data may be required before these relationships can be determined in a manner that reasonably provides accurate values ​​for predicted conditions. For example, a certain number of usage cycles may be needed before a fit with acceptable associated error can be produced, based on which predicted conditions are determined. In some examples, usage conditions for one hundred usage cycles may be required before determining wear relationships and / or brake length relationships.

[0101] Indications regarding the number of future use cycles of brake 200 can be provided to ground crew and / or the pilot of aircraft 100 and / or other personnel involved in the maintenance of aircraft 100. For example, such indications can be provided using one or more of the indicating devices 110. In some examples, the number of future use cycles can be transmitted (e.g., via a data communication network) to equipment located remotely from aircraft 100. This advantageously allows for the scheduling of brake 200 maintenance. If it is known when brake 200 may require maintenance or replacement of the entire brake 200 or a portion thereof, delays due to landing of aircraft 100 (when brake 200 is found to require maintenance, etc.), short-term notification arrangements for brake 200 maintenance, etc., can be avoided. Therefore, the operational efficiency of aircraft 100 can be improved compared to not having indications regarding the number of future use cycles of brake 200.

[0102] Processor 302 can be configured to compare the predicted condition of brake 200 with the condition of brake 200 determined based on one or more measured characteristics of brake 200. For example, once a given service life has occurred, processor 302 can compare the predicted wear state for the given service life with the wear state for the given service life (i.e., the measured wear state). For example, after a given service life has occurred, processor 302 can compare the predicted brake length value for the given service life determined prior to the given service life (e.g., using the brake length relationship as described) with the predicted brake length value determined using the measured wear value and the oxidation length for the given service life.

[0103] Based on comparison, processor 302 can determine whether a brake alarm criterion is met. For example, processor 302 can determine the expected range of brake conditions for the next usage cycle, and the brake alarm criterion can be met if the predicted condition in question falls outside the expected range of brake conditions. For example, if the condition of brake 200 for a given number of usage cycles (e.g., wear condition of brake 200 / brake length value of brake 200) is known, processor 302 can determine the range into which the condition for the next usage cycle is expected to fall. The expected range of brake conditions can be a range centered on the predicted condition for the next usage cycle. In the example of determining the predicted condition based on a wear relationship or brake length relationship, the expected range of brake conditions can be determined based on the error value associated with the fit used to determine the wear relationship or brake length relationship (e.g., a fit of wear condition or brake length using equation (1)). It should be understood that any data fit has an associated error that relates to how accurately the fit represents the relevant data. For example, there may be a standard deviation value associated with the predicted condition for each future usage cycle. In some examples, the expected brake condition range for the next usage cycle may include twice the standard deviation above and below the predicted condition for the next usage cycle (in the predicted usage condition based on the relevant fit).

[0104] For example, as in Figure 4In one example, if one hundred use cycles have occurred, processor 302 can determine the expected wear condition range for the one hundred and first use cycle. The expected wear condition range can be twice the standard deviation associated with the fit above and below the predicted wear condition for the next use cycle. In other examples, the expected brake condition range can be determined in different ways. For example, when oxidation is considered only, the expected brake condition range for the next use cycle can be determined based on the worst-case and best-case expected temperature characteristics of brake 200 for the next use cycle. The worst-case expected temperature characteristics could include brake 200 being at relatively high temperatures for a relatively long period, while the best-case expected temperature characteristics could include brake 200 avoiding high temperatures that can be reasonably expected for the next use cycle (e.g., considering the runway length for the next use cycle).

[0105] When the next usage cycle has occurred, processor 302 can determine whether the relevant condition falls outside the expected brake condition range. After the next usage cycle occurs, processor 302 can determine the relevant condition based on the latest relevant measurements and compare the condition with the expected brake condition range. For example, processor 302 can determine the expected wear condition range for the 101st usage cycle before it occurs. After the 101st usage cycle has occurred, processor 302 can receive the latest measured wear value from wear sensor 216 and determine the latest wear condition. Processor 302 can then check whether the latest wear condition falls outside the expected wear condition range. Similarly, processor 302 can compare the latest brake length, oxidation state, etc., with the expected brake length range, expected oxidation range, etc., as appropriate.

[0106] A condition where brake 200 falls outside the expected brake condition range can indicate unexpected or abnormal behavior of brake 200. Processor 302 can be configured to provide an indication that a brake alarm criterion is met. If the condition falls outside the expected brake condition range, an indication can be provided to ground crew and / or the pilot of aircraft 100, for example, using one of the indication devices 110. In some examples, such an indication can be provided if the condition falls outside the corresponding expected brake condition range for a given number of consecutive (e.g., three) usage cycles. For example, based on such an indication, maintenance or replacement of the entire brake 200 or a portion of brake 200 can be performed, or adjustments related to braking behavior (i.e., how the brakes are applied) can be made. In some examples, a specific brake control function that controls brake operation to control the condition of brake 200 can be activated.

[0107] Processor 302 can execute any of the procedures described above as a method for determining the number of future use cycles of brake 200 based on predicted conditions of brake 200. Device 300 may include a computer-readable storage medium 304 thereon storing instructions that, when executed by processor 320, will cause processor 302 to perform the method according to the described example.

[0108] The device 300 performing these methods may be deployed on the aircraft 100. In some examples, the processor 302 may be a processor of the computing system 106 and the computer-readable storage medium 304 may be a computer-readable storage medium of the computing system 106. In some examples, the device 300 may be located remotely from the aircraft 100. In these examples, the device 300 may be configured with relevant information for the device 300 to perform the described processes, such as the usage characteristics of the measurements.

[0109] Figure 7 A method 700 for determining the thermal oxidation state of a brake, such as brake assembly 200, of an aircraft landing gear assembly 102 according to an embodiment of the present invention is summarized. Method 700 includes using a thermal oxidation model to determine the thermal oxidation state of brake assembly 200 after a braking event based on an initial thermal oxidation state prior to a braking event (also referred to as the initial thermal oxidation level) and a temperature profile of the brake over time. The determined thermal oxidation state of brake assembly 200 after a braking event is also referred to as the updated thermal oxidation state. This is because the thermal oxidation state of brake assembly 200 after a braking event takes into account the change in the initial thermal oxidation state caused by the braking event.

[0110] A braking event is an event related to the application of brake assembly 200. For example, a braking event may include one or more applications of brake assembly 200 to slow or stop aircraft 100. In some examples, a braking event may be a portion of a period during which brake assembly 200 is continuously applied. Whenever brake assembly 200 is applied, the temperature of brake assembly 200 may rise. This is because when brake assembly 200 is applied to reduce the speed of aircraft 100, some of the kinetic energy of aircraft 100 is absorbed as heat into brake assembly 200, causing its temperature to rise. Therefore, the temperature change of brake assembly 200 can be used to determine whether brake assembly 200 has been applied.

[0111] At block 702 of method 700, a temperature profile and initial thermal oxidation state of the brake assembly 200 are input. As explained above, the temperature profile indicates the temperature change over time. The input temperature profile may, for example, be related to the service life of the aircraft 100. For example, the temperature profile may be for the entire service life of the aircraft 100, such as from the time the aircraft 100 is at the departure point before flight to the time the aircraft 100 is at the arrival point after flight. In particular, the temperature profile may indicate the temperature change over time for all braking events that occur during a cycle. In other examples, the temperature profile may not be for the entire service life of the aircraft 100. For example, the temperature profile may be for a single braking event or a portion of a cycle with many braking events. In some examples, a number of temperature profiles belonging to a particular service life may be used to determine the thermal oxidation state of the brake assembly 200 after that service life.

[0112] For example, the temperature profile can be related to a usage cycle that has already occurred. In other words, the temperature profile can include actual data from the temperature sensor 216 of the aircraft 100 during a previous usage cycle. In such an example, the temperature profile is related to real data. On the other hand, in some examples, the temperature profile can be a predicted temperature profile for a predicted future usage cycle of the aircraft 100. In this context, the braking event can be a predicted future braking event.

[0113] The initial thermal oxidation state of brake assembly 200 is the thermal oxidation state of brake assembly 200 prior to a braking event, and the updated thermal oxidation state is determined with respect to that oxidation state. For example, for a new brake assembly 200 installed in aircraft 100, the initial oxidation state may indicate no oxidation. In some examples, the initial oxidation state for a newly installed brake assembly 200 may be set by aircraft maintenance personnel at the time of installation and may indicate no oxidation or some degree of oxidation as assessed by the personnel performing the installation. In examples where brake assembly 200 is not a new brake assembly, the initial oxidation state may be the oxidation state calculated at a previous moment in the execution of method 700. In some examples, a non-new brake or brake component may be installed on aircraft 100. If temperature profile information for all previous braking events involving the brake or brake component is available, the available temperature profile information may be used to determine the thermal oxidation state at the time of installation using method 700 or other methods disclosed herein.

[0114] At block 704 of method 700, a thermal oxidation model is used to determine the thermal oxidation state (updated thermal oxidation state) following the braking event. For example, a thermal oxidation model is applied based on the input temperature profile and the initial thermal oxidation state of the brake assembly 200. For example, the thermal oxidation state indicates how the expected thermal oxidation state changes over time for various temperatures, starting from the initial thermal oxidation state. The thermal oxidation model is a model of the thermal oxidation evolution of the brake. For example, which thermal oxidation state is used may depend on the initial thermal oxidation state. Details and selection of appropriate thermal oxidation models are further described below. In some examples, method 700 may be performed in the field during the service life of aircraft 100. In the case of performing method 700 in the field (i.e., in real-time or near real-time), for example, the temperature profile used may be derived from temperature data acquired so far by temperature sensor 216. Therefore, at block 704, it is determined how the oxidation state changes from the initial oxidation state due to the increased temperature associated with the braking event in question.

[0115] After determining the updated thermal oxidation state, the initial thermal oxidation state can be set to the updated thermal oxidation state. In this way, the initial thermal oxidation state always follows all previous braking events. In examples where the temperature profile involves more than one braking event, method 700 can be executed again to determine the updated thermal oxidation state after subsequent braking events. Updating the initial thermal oxidation state in this way ensures that the initial thermal oxidation state used for subsequent braking events takes into account all previous braking events.

[0116] In an example of a temperature profile for the entire service life of the aircraft 100, method 700 can be performed to determine the corresponding updated thermal oxidation state after each braking event within that service life. It should be understood that this process can be performed sequentially relative to the chronological order of the braking events. This allows the determination of the updated thermal oxidation state for each braking event to be performed from the starting point (initial thermal oxidation state) considering all previous braking events.

[0117] In method 700, for example, an appropriate thermal oxidation model can be used to determine the updated thermal oxidation state after the braking event based on the high temperature interval, the initial thermal oxidation state, and the thermal oxidation rate parameter.

[0118] Figure 8This is a flowchart illustrating a method 800 that can be performed as part of method 700. For example, method 800 relates to a more specific example of block 704 of method 700. Block 802 is identical to block 702 of method 700, where a temperature profile of the brake relative to time and the initial thermal oxidation state of the brake assembly 200 are input. At block 804, the temperature profile is compared to a set of temperature standards. This set of temperature standards includes a set of temperature thresholds. For example, the set of temperature standards may include a first temperature threshold of 400°C and a second temperature threshold of 750°C. In other examples, different temperature thresholds may be used depending on the physical properties of the brake assembly 200. For example, the comparison of the temperature profiles may be performed sequentially according to the chronological order of the temperature data contained in the temperature profiles. For example, a temperature value may be compared to the set of temperature thresholds, and subsequently, the next temperature value may be compared to the set of temperature thresholds.

[0119] In box 806, it is determined whether one or more temperature criteria are met. For example, if no temperature threshold is exceeded, method 800 ends. It should be understood that thermal oxidation of the CC compound of the brake disc 202 is the most significant process at high temperatures. Therefore, comparison of temperature profiles with a set of temperature thresholds identifies high-temperature events corresponding to braking events that may lead to thermal oxidation. As mentioned above, for example, a braking event is the application of brake assembly 200. However, a high-temperature event is an event in which the temperature of the brake assembly exceeds at least one of the temperature thresholds due to the braking event. For example, if the temperature of brake assembly 200 remains below all temperature thresholds during a braking event (i.e., brake application), then no high-temperature event occurs during that braking event. On the other hand, if the temperature of the brake assembly exceeds a temperature threshold during a braking event, the portion of the braking event exceeding the temperature threshold can be referred to as a high-temperature event. If more than one temperature threshold is exceeded, then a high-temperature event is the portion of the braking event exceeding the highest temperature threshold.

[0120] A temperature threshold can be set based on the following temperature: above which a significant amount of thermal oxidation is expected. Therefore, if no temperature threshold is exceeded, method 800 terminates. This is because, in this example, no braking event occurs that would cause a sufficiently high temperature for thermal oxidation. In such an example, the updated thermal oxidation state after the braking event can simply be set to the initial thermal oxidation state prior to the braking event in question.

[0121] On the other hand, if at least one of the temperature thresholds is exceeded, a high-temperature event corresponding to the braking event in question is identified at block 808 of method 800. A high-temperature event corresponds to the portion of the temperature curve that exceeds the highest temperature threshold among the exceeded temperature thresholds. This is because the portion of the temperature curve that exceeds the highest threshold among the exceeded thresholds corresponds to the portion of the braking event that exceeds the highest temperature threshold. (See also...) Figure 9 The identification of high-temperature events is described. Figure 9 This is a graph illustrating a portion of an example temperature curve. Figure 9 In the graph, the vertical axis represents the temperature of the brake assembly 200, and the horizontal axis represents time. In this example, the curve portion 902 indicates that the temperature of the brake assembly 200 exceeds a first temperature threshold 904 and a second temperature threshold 906. In this example, a high-temperature event is identified as the portion of curve 902 above the second temperature threshold 906, because the second temperature threshold 906 is the highest temperature threshold exceeded.

[0122] Compared to thermal oxidation occurring above a first temperature threshold 904 but below a second temperature threshold 906, the amount of thermal oxidation occurring above the second temperature threshold 906 can be significantly greater over a given interval. Therefore, in this example, the portion of the temperature curve below the second temperature threshold 906 is not considered. In other examples, for example, when method 800 is used for real-time oxidation state monitoring as further described below, the portion of the temperature curve between the two temperature thresholds can be considered. It should be understood that... Figure 9 The curve is merely an illustrative example for purposes of explanation.

[0123] At box 810, the time interval occupied by the high-temperature event is defined as the high-temperature interval. As mentioned above, the updated thermal oxidation state can be determined based on the high-temperature interval (among other factors). Figure 9 In the example, the high-temperature interval was determined to be a time interval of 908.

[0124] At box 812, a high-temperature event value for brake assembly 200 is determined for a high-temperature interval. The high-temperature event value is the temperature attributed to a high-temperature event. In some examples, the high-temperature event value is the average temperature during the high-temperature interval. An alternative to the high-temperature event value as an average temperature is described below in the context of real-time oxidation monitoring.

[0125] At box 814, the oxidation rate parameter is calculated based on the high-temperature event value and physical property information of the brake. For example, the oxidation rate parameter for the thermal oxidation reaction can be determined based on the Arrhenius formula shown in Equation 1 below:

[0126]

[0127] In Equation 3, k(T) is the thermal oxidation rate, A is the pre-constant, and E... A R is the activation energy of the carbon atoms in the CC composite component of brake assembly 200, R is the universal gas constant, and T is the temperature. In this example, for a specific high-temperature event, the temperature T in Equation 3 is set to the high-temperature event value for the purposes of box 814. In this example, the thermal oxidation rate k(T) is the oxidation parameter determined at box 814. Activation energy E A The values ​​of the pre-exponential constant A depend on the physical properties of the CC compound of brake assembly 200 (brake disc 202 in this example). For example, the values ​​of these parameters can depend on density, porosity, manufacturing process, contaminants present in the CC compound structure, surface finish of the component, and surface coatings of brake assembly 200. Activation energy E A Furthermore, the value of the pre-exponential constant A can also change based on the high-temperature event value and the initial thermal oxidation state. Therefore, to determine the oxidation parameters, the activation energy E can be selected based on the physical properties of the brake assembly 200, the high-temperature event value, and the initial thermal oxidation state prior to the braking event under discussion. A And a suitable value for the pre-exponential constant A.

[0128] For example, activation energy E A It can be inversely proportional to temperature. Activation energy E A The activation energy E may decrease at temperatures where oxygen molecules can penetrate the surface of the brake disc 202 and deeper carbon within the brake disc 202 can undergo oxidation. For example, the activation energy E can be experimentally determined for different initial thermal oxidation levels, temperatures, and physical characteristics of the brake considered prior to the implementation of method 800. A The appropriate value for the pre-exponential factor A.

[0129] Figure 10 This is a graph illustrating an example of the evolution of the thermal oxidation state of the brake disc of brake assembly 200 at a specific temperature over time. Figure 10 The vertical axis of the graph represents a measured value of thermal oxidation, expressed as the thermal oxidation state Ox. For example, the thermal oxidation state Ox can be proportional to the mass loss of brake assembly 200 due to thermal oxidation of brake disc 202. Evolution curve 1002 shows how the proportion of mass loss due to thermal oxidation increases over time at a specific temperature. It should be noted that different evolution curves will represent the change of the thermal oxidation rate Ox over time for different temperature values.

[0130] In this example, the thermal oxidation state Ox changes over time in a different manner below thermal oxidation state level 1004 than it does above it. In this example, the thermal oxidation state Ox (i.e., the mass loss due to thermal oxidation) is shown to increase non-linearly over time below oxidation state level 1004 and to change approximately linearly over time above it. In this example, the thermal oxidation state increases at an accelerating rate over time until it reaches thermal oxidation state level 1004. After reaching thermal oxidation state level 1004, the rate of change of the thermal oxidation state Ox over time remains approximately constant. Figure 10 The portion of the curve below the thermal oxidation state level 1004 can be considered, for example, as the first thermal oxidation region, i.e., region 1, and Figure 10 The portion of the curve above the thermal oxidation state level 1004 can be considered, for example, as a second thermal oxidation region, i.e., region 2.

[0131] In some examples, different activation energies E can be used depending on which thermal oxidation region the brake assembly 200 is in, as indicated by its initial thermal oxidation state. A Value and pre-exponential factor A value.

[0132] At box 816, a thermal oxidation model is selected based on the initial thermal oxidation state prior to the braking event. The thermal oxidation model describes the evolution of the thermal oxidation state Ox of the brake assembly 200 for different temperature values. When the initial thermal oxidation state is in region 1, a thermal oxidation model describing the evolution of the thermal oxidation state Ox in region 1 can be selected. When the initial thermal oxidation state is in region 2, a thermal oxidation model describing the evolution of the thermal oxidation state Ox in region 2 can be selected. For example, a first thermal oxidation model, model 1, can be selected for region 1, and a second thermal oxidation model, model 2, can be selected for region 2. Model 1 for region 1, describing the nonlinear change of the thermal oxidation state Ox over time, can be represented by Equation 4. Model 2 for region 2, describing the linear change of the thermal oxidation state Ox over time, can be represented by the following Equation 5.

[0133]

[0134] In equations 4 and 5 above, k(T) is the thermal oxidation rate defined by equation 3. The parameter t... eq This is the equivalent time, which is the time it would take to reach the thermal oxidative state Ox at temperature T. The parameter n refers to the order of the formula and depends on the properties of the CC composite material used in the brake assembly 200. The parameter n can be determined experimentally, for example, for a brake using a specific CC composite material.

[0135] In some examples, a different thermal oxidation model than the thermal oxidation models described in Equations 4 and 5 may be used. In some examples, a single thermal oxidation model may be used, which describes the evolution of thermal oxidation states Ox for all thermal oxidation states Ox associated with brake assembly 200. In some examples, more than two thermal oxidation models may be used for a given range of thermal oxidation states Ox. Method 800 may be modified appropriately to use such alternative thermal oxidation models. For example, a different set of inputs than those described in this particular example of method 800 may be applied to the thermal oxidation model, depending on the circumstances.

[0136] It will be understood that once box 802 has been executed, box 816 can be executed at any stage of method 800, because box 816 requires an initial thermal oxidation state.

[0137] At box 818, the updated thermal oxidation state for the high-temperature event is determined using the selected thermal oxidation model based on the high-temperature interval, the initial thermal oxidation state, and the determined thermal oxidation rate parameter. For example, the time taken to reach the initial thermal oxidation state from zero at the high-temperature value is determined, and the high-temperature interval is added to this time to determine the t to be used in the selected thermal oxidation model. eq The value of t will be determined from this. eq The values ​​of the values ​​and thermal oxidation parameters are input into the equations selected from Equations 4 and 5 above, resulting in an updated thermal oxidation state of the brake assembly 200 after a high-temperature event as the output.

[0138] The updated thermal oxidation state can be set as the new initial thermal oxidation state for subsequent use of method 800 in response to subsequent high-temperature events in the temperature profile.

[0139] In some examples, methods 700 and / or 800 can be performed in real time during the usage cycle in which the braking event is occurring. In such examples, for example, a portion of method 800 can be modified to allow real-time brake oxidation monitoring, and the temperature profile can correspond to the temperature values ​​measured in real time. For example, the temperature information provided by temperature sensor 216 can be continuously compared with the set of temperature standards according to block 804 of method 800, and the high-temperature time can be identified substantially when a high-temperature event occurs. It will be understood that even though this type of oxidation state monitoring is described as real-time, the extent to which this type of oxidation state monitoring is performed in real time will depend on the limitations of various hardware and software (e.g., processing speed). For example, there may be a time delay between the temperature values ​​measured by temperature sensor 216 corresponding to the high-temperature event and those values ​​that lead to an update of the thermal oxidation state of brake assembly 200.

[0140] For example, a high-temperature event can be identified as a smaller portion of the temperature curve than the example described above. See again... Figure 9 The portion of curve 902 occurring within the time interval represented by 910 can be considered a high-temperature event, and interval 910 is considered a high-temperature interval of the high-temperature event. In this example, the high-temperature event value can be considered, for example, the temperature value measured at the beginning or end of the high-temperature interval 910, or the average of the two temperature values. Unlike the example above, in the case of real-time monitoring, even when the temperature exceeds the second temperature threshold 906, the portion of the temperature curve between the first and second temperature thresholds can be considered. In the case of real-time monitoring, any portion of the temperature curve above at least one temperature threshold, such as the portion represented by interval 910, can be identified as a high-temperature event. It will be understood that this modification allows the thermal oxidation state of the brake assembly 200 to be updated when a high-temperature event corresponding to a braking event is occurring. In some examples, a high-temperature event can be identified based on the time between subsequent temperature measurements obtained by temperature sensor 216. For example, interval 910 can be the time between subsequent temperature measurements obtained by temperature sensor 216.

[0141] Methods 700 and 800 can be used to determine the thermal oxidation state of the brake assembly 200 in real time, either after or during an actual service cycle of the aircraft 100. In this example, this can be based on one or more temperature profiles covering braking events within the service cycle. As mentioned above, in some examples, the thermal oxidation state of the brake assembly 200 is determined using temperature profile information collected by temperature sensor 216 with respect to a service cycle that has actually occurred.

[0142] On the other hand, in some examples, method 700 or method 800 can be used to predict the future thermal oxidation state of the brake assembly 200 after a first plurality of predicted future use cycles of the aircraft 100. The first plurality of future use cycles can be cycles after which a thermal oxidation threshold is reached. Each predicted future use cycle can include a corresponding plurality of braking events. For each predicted future use cycle, the prediction can be based on a corresponding predicted temperature profile of the actuator assembly 200 and the current thermal oxidation state. The current thermal oxidation state is, for example, taking into account the oxidation state of all previous braking events experienced by the brake assembly 200.

[0143] For example, the predicted temperature profile can be input into method 700 or method 800, for instance, in chronological order, to determine the future thermal oxidation state of the brake assembly 200. This predicted temperature profile for the predicted future service life can be based on a previous temperature profile for a previous actual service life of the aircraft 100. For example, the landing phase portion of the previous temperature profile can be used to predict the landing phase portion of the temperature profile for the future service life. For the purpose of predicting the future thermal oxidation state, when method 700 or method 800 is executed for an actual service life of the aircraft 100, high-temperature events, high-temperature event values, etc., can be stored in a computer-readable storage medium.

[0144] In some examples, data from previous cycles may be unavailable, for example, because the brake assembly 200 may be new. In some examples, there may not be enough available data to reliably predict the temperature profile for the predicted future usage cycles. In such examples, a predetermined temperature profile can be used. The predetermined temperature profile may be a profile typically expected for the future usage cycles of the aircraft 100.

[0145] The predicted temperature profile can, for example, take into account the future flight schedule of aircraft 100. For instance, aircraft 100 may be anticipated to land at an airfield with a short runway, thus requiring high-energy (i.e., high-temperature) braking upon landing for some of the predicted future service cycles of the aircraft. For those predicted future service cycles, the predicted temperature profile indicates high-energy braking upon landing. It will be understood that when predicting the temperature profile, various other factors can be taken into account, such as taxiing time at various stages of the predicted future service cycle, and waiting time between the taxiing phase and the previous landing phase.

[0146] As mentioned above, the first plurality of predicted future use cycles can be a plurality of predicted future use cycles after which the predicted future thermal oxidation state reaches a thermal oxidation threshold. For example, prediction of the future thermal oxidation state can be stopped after a cycle in which the thermal oxidation threshold is reached. In some examples, prediction of the future thermal oxidation state can be stopped as soon as the thermal oxidation threshold is reached. The thermal oxidation threshold can be an oxidation state in which brake assembly 200 or a component of brake assembly 200 requires repair or replacement. For example, brake assembly 200 may require repair if the mass of brake assembly is reduced by between 4% and 6.5%, for example, by 5.7%, where the selected percentage threshold can vary, for example, based on the original manufactured disc density. In this example, the first plurality of predicted future use cycles are the plurality of cycles in which the mass loss due to thermal oxidation reaches or exceeds, for example, 5.7% (i.e., in the range between 4% and 6.5%).

[0147] On the other hand, in some examples, the prediction of future thermal oxidation state can cease at the end of one of the predicted future use cycles: during said predicted future use cycle, the future thermal oxidation state is almost close to the thermal oxidation threshold, such that the future thermal oxidation state can be expected to reach the thermal oxidation threshold during the next predicted future use cycle. In such examples, the thermal oxidation threshold can be considered to have been reached within the first plurality of predicted future use cycles. This is because, in practice, an aircraft 100 having a brake assembly 200 that is expected to reach the thermal oxidation threshold in a strict sense exactly in the next cycle will not be permitted to fly, and at this time, maintenance or replacement related to the brake assembly 200 can be performed.

[0148] Using the first plurality of predicted future usage cycles, an indication can be given regarding how many usage cycles can occur before the brake assembly 200 or a component of the brake assembly 200 requires repair or replacement due to thermal oxidation. In an example where the thermal oxidation threshold is strictly reached or exceeded during the last future cycle of the first plurality of future cycles, the number of cycles before requiring repair or replacement due to thermal oxidation can be predicted as one less than the number of cycles in the first plurality. In an example where the prediction of future thermal oxidation states ceases when the thermal oxidation threshold is expected to be reached in the next cycle after the first plurality, the first plurality is considered to be the number of cycles before requiring repair and replacement due to thermal oxidation.

[0149] Figure 11This is a flowchart of method 1100, which determines the amount of brake wear caused by a braking event based on the amount of energy absorbed by the brake assembly 200 due to a braking event and the density parameters of the brake assembly 200 using a brake wear model. The amount of brake wear can be determined for all braking events in which energy is input into the brake assembly 200 during friction processes that will lead to wear on the surface of the brake disc. For example, wear of the brake disc due to friction can cause the length of the brake disc 202 to decrease as the brake disc material is lost under friction.

[0150] For example, brake wear can be determined for braking events that do not involve any high-temperature events. For method 1100, a braking event can be identified, for example, based on a temperature profile, as an event indicating an increase in the temperature of the brake assembly 200. In some examples, a braking event can be simply identified based on an indication that the brake assembly 200 has been applied. For example, the computing system 106 of the aircraft 100 can detect when the brake assembly 200 is applied and when it is released.

[0151] At block 1102 of method 1100, the energy input to brake assembly 200 during a braking event is determined. The energy input to brake assembly 200 can be determined, for example, based on characteristics of aircraft 100 during the braking event—such as the mass of aircraft 100, the speed of aircraft 100 during the braking event, etc. The energy absorbed by brake assembly 200 can be calculated based on these characteristics of aircraft 100 by determining the kinetic energy of aircraft 100. For example, a given proportion of the kinetic energy of aircraft 100 can be absorbed by brake assembly 200 to reduce the kinetic energy of aircraft 100. In some examples, the energy input to brake assembly 200 can be determined based on measurements obtained by instrument 108 of aircraft 100. For example, instrument 108 may include a tachometer associated with wheel 104, which is associated with brake assembly 200. In this example, the tachometer measures the rotational speed of wheel 104, and the energy absorbed by brake assembly 200 can be determined using the change in rotational speed relative to time.

[0152] In other examples, if the mass of brake assembly 200 is known, the absorbed energy can be determined based on the increase in temperature of brake assembly 200, taking into account the specific heat of brake assembly 200. In some examples, the mass of brake assembly 200 can be determined based on the thermal oxidation state of brake assembly 200 as determined by the method described above, because: as described above, the thermal oxidation state can be expressed as the amount of mass loss of brake assembly 200 due to thermal oxidation.

[0153] At block 1104 of method 1100, the density parameter of brake assembly 200 is determined. Taking into account mass loss, the density parameter is, for example, a parameter indicating the reduction in the density of brake assembly 200 compared to its original density. The density of brake assembly 200 may decrease, for example, due to thermal oxidation. It will be understood that thermal oxidation leads to a decrease in mass because carbon atoms react with oxygen to form carbon dioxide or carbon monoxide, and thus carbon atoms are removed from brake disc 202. However, thermal oxidation may not necessarily change the volume of brake disc 202. This is because thermal oxidation may not act uniformly on a particular surface of the brake disc but may occur at a certain depth within the brake disc.

[0154] The density parameter can be expressed as (1-Ox), where the thermal oxidation state Ox is represented as a number between 0 and 1. For example, the density of brake assembly 200 is reduced by a factor (1-Ox) compared to its initial density before any thermal oxidation occurs (i.e., when brake assembly 200 is new). Therefore, the density parameter can be determined based on the initial oxidation state before the braking event.

[0155] In some examples, the reduced density of brake assembly 200 can be determined based on measurements performed by instruments included in instrument 108. For example, the mass of brake assembly 200 can be calculated based on the amount of energy absorbed by brake assembly 200 (e.g., based on measurements from a tachometer) and the subsequent temperature rise of brake assembly 200 (e.g., based on measurements from temperature sensor 216). The reduced density of brake assembly 200 can be determined based on the calculated mass of brake assembly 200. Aircraft 100 may include a wear pin associated with brake assembly 200. Typically, the wear pin provides an indication of the reduction in the length L of the brake, and thus an indication of brake wear. For example, the wear pin can be checked by ground personnel between cycles, and updated volume values ​​of brake assembly 200 can be obtained. In some examples, other methods of measuring changes in the length L of brake assembly 200 may exist. For example, a length sensor can be provided for brake assembly 200, and / or an electrically actuated brake can be used. Updated volume values ​​can be determined based on the reduced length L and used to determine the reduced density based on the mass. During a single cycle, the volume change of the brake assembly 200 may be negligible for the purpose of calculating density parameters, and updated volumes can be obtained after multiple cycles. Based on the reduced density, the density parameters can be determined.

[0156] At block 1106 of method 1100, the amount of brake wear caused by a braking event is determined using a brake wear model based on the energy absorbed by the brake assembly 200 and the density parameter from block 1104. For example, the mass lost by the brake assembly 200 due to wear during a wear event is determined using the brake wear model of Equation 6 below.

[0157]

[0158] In equation 6 above, m wear E is the mass lost due to wear during a braking event. brake The energy absorbed by the brake assembly 200 is W, X, Y, and Z, which are constants. These constants W, X, Y, and Z can be determined in advance, for example, through experimentation, and can vary depending on the characteristics of the brake assembly 200. The amount of brake wear during a braking event can be determined based on the reduction in mass of the brake assembly 200 during the braking event due to the decrease in brake wear, as a reduction in the length L of the brake assembly 200.

[0159] As described above, in some examples, the initial thermal oxidation rate is used to determine the density parameter. In these examples, the initial thermal oxidation state can be used to determine block 1106 when a braking event occurs—which also occurs during the braking event. This is because brake wear occurs in a shorter time period than thermal oxidation.

[0160] The amount of brake wear determined for a braking event can be added to the amount of brake wear for all previous braking events of the brake assembly 200 to determine the total amount of brake wear.

[0161] For example, method 1100 can be executed in real time during a braking event, or in real time within the already occurred usage cycle using relevant data from the usage cycle. Method 1100 can also be used to predict future brake wear of the brake assembly 200 after a second plurality of predicted future usage cycles of the aircraft 100. The second plurality of predicted future usage cycles can be a plurality of cycles after which a thermal oxidation threshold is reached. Each predicted future usage cycle can include a corresponding plurality of braking events. For example, method 1100 can be executed for each braking event in the second plurality of predicted future usage cycles. The wear amounts from each of these braking events can be summed to predict the future brake wear amount for the second plurality of predicted future usage cycles. For each predicted future usage cycle, the prediction can be based on the predicted amount of energy absorbed by the brake during the corresponding braking event and a corresponding predicted density parameter of the brake for the corresponding braking event. For example, braking events can be identified and the energy absorbed by the brake assembly 200 for these braking events can be determined based on a predicted temperature profile. In other examples, the predicted amount of absorbed energy can be based on data from previous cycles. If the brake assembly 200 is new, or if sufficient prior data is not available, the amount of energy to be predicted can be determined in advance.

[0162] To predict future brake wear, method 1100 can be used in conjunction with method 700 or 800. In these examples, the latest initial thermal oxidation state is known exactly before each predicted braking event (e.g., a predicted future braking event). In this way, the mass of brake assembly 200, and therefore its density parameter, can be determined using the initial thermal oxidation prior to the future braking event in question.

[0163] As described above, the second plurality of predicted future use cycles can be multiple predicted future cycles after which the predicted future brake wear amount reaches the brake wear threshold. For example, the prediction of future brake wear amount can be stopped after the cycle that reaches the brake wear threshold. In some examples, the prediction of future brake wear amount can be stopped once the total brake wear amount reaches the brake wear threshold. The brake wear threshold can be the total amount of brake wear at which the brake assembly 200 or a component of the brake assembly 200 needs to be repaired or replaced. For example, in the brake assembly, such as... Figure 2If the length L of the brake assembly 200 is reduced by, for example, 22% to 24% depending on the type of disc and its initial manufacturing density, the brake assembly may require repair. For an exemplary disc with an initial length L of approximately 221 mm, a length reduction of approximately 50 mm may necessitate repair or replacement. In this example, the second plurality of predicted future service cycles is the number of cycles required for the total brake wear to reach or exceed, for example, 50 mm (again, for an initial disc with a length L of approximately 221 mm).

[0164] On the other hand, in some examples, the prediction of future brake wear can cease at the end of a predicted future service period during which the total brake wear is close to the brake wear threshold, such that the total brake wear can be expected to reach the brake wear threshold in the next predicted future service period. In this example, it can be assumed that the brake wear threshold is reached within a second or more predicted future service periods. This is because, in practice, the aircraft 100 with brake assembly 200, which is strictly expected to reach the brake wear threshold in the next period, will not be permitted to fly, and maintenance or replacement related to brake assembly 200 may occur at that point.

[0165] By using a second plurality of predicted future use cycles, an indication can be given of how many use cycles can occur before brake assembly 200 or a component of brake assembly 200 requires repair or replacement due to brake wear. In an example where the brake wear threshold is strictly reached or exceeded during the last cycle of the second plurality of predicted future use cycles, the number of cycles before repair or replacement due to brake wear can be predicted as one less than the number of cycles in the second plurality of predicted future use cycles. In an example where the prediction of future brake wear is stopped when the brake wear threshold is expected to be reached in the next cycle following the second plurality of predicted future use cycles, the second plurality of predicted future use cycles are considered as the number of cycles before repair or replacement is required.

[0166] Figure 12This is a flowchart of a method 1200 for determining the number of good future service cycles before reaching one of a thermal oxidation threshold and a brake wear threshold. The number of good future service cycles is the number of remaining service cycles before reaching one of the thermal oxidation threshold or the brake wear threshold. Method 1200 can be performed for several predicted future service cycles until a first threshold is reached. Method 1200 includes predicting the future thermal oxidation state and future brake wear after the predicted future service cycle, and, if one of the thermal oxidation threshold and the brake wear threshold is reached, determining the number of good future service cycles before reaching either threshold. If one of the thresholds is not reached, a prediction is performed for the next predicted future service cycle. As in the example above, each predicted future service cycle includes multiple braking events. For each predicted future service cycle, the prediction is based on the corresponding predicted temperature profile of the brake, the current thermal oxidation state, the predicted amount of energy absorbed by the brake during the corresponding braking event, and the corresponding predicted density parameter of the brake for the corresponding braking event.

[0167] The number of good future service cycles is the number of cycles after which brake assembly 200 or its components will require maintenance or replacement. It should be understood that maintenance or replacement of brake assembly 200 may be performed when either a thermal oxidation threshold or a brake wear threshold is first reached. The first threshold reached may depend, for example, on the handling of aircraft 100 during its service and its flight schedule. For instance, if aircraft 100's schedule involves flights to most airports with long runways, short taxiways, etc., the brake wear threshold may be reached first. This is because, in this example, the temperature of brake assembly 200 may not frequently exceed any temperature threshold associated with thermal oxidation. On the other hand, aircraft 100 may frequently experience high-energy braking (e.g., due to short runways), resulting in temperatures exceeding the threshold associated with thermal oxidation. In this example, the thermal oxidation threshold may be reached first.

[0168] At block 1202 of method 1200, the future thermal oxidation state after the predicted future service life is predicted. The prediction of the future thermal oxidation state is performed as described above, for example, using an appropriate thermal oxidation model based on the predicted temperature profile of the predicted future service life discussed. At block 1204 of method 1200, the future brake wear amount after the same predicted future service life is predicted. The prediction is performed in the context of method 1100 as described above.

[0169] At block 1206 of method 1200, it is determined whether a thermal oxidation threshold and / or a brake wear threshold has been reached. For example, if the thermal oxidation threshold is reached, method 1200 proceeds to block 1208, where the number of good future service cycles is determined before either the thermal oxidation threshold or the brake wear threshold is reached, and method 1200 ends. For example, if the thermal oxidation threshold is strictly reached or exceeded after a given number of predicted future service cycles, the number of good future service cycles is one less than the given number. For example, if the thermal oxidation threshold is expected to be reached in the next predicted future service cycle, the number of good future service cycles is determined to be the number of predicted future service cycles for which method 1200 has been performed so far.

[0170] On the other hand, if it is determined that the brake wear threshold has been reached, the method proceeds to block 1208, where the number of good future use cycles is determined, and method 1200 ends. For example, if the brake wear threshold is reached or exceeded strictly after a given number of predicted future use cycles, the number of good future use cycles is one less than the given number. For example, if the brake wear threshold is expected to be reached in the next predicted future use cycle, the number of good future use cycles is determined to be the number of predicted future use cycles for which method 1200 has been performed so far.

[0171] For example, if both thresholds are reached, method 1200 proceeds to box 1208, where the number of remaining good future use cycles is determined before either the thermal oxidation threshold or the brake wear threshold is reached, and method 1200 terminates. In this example, if at least one of the thresholds is strictly reached or exceeded after a given number of predicted future use cycles, the number of good future use cycles is one less than the given number. Otherwise, the number of good future use cycles is determined to be the number of predicted future use cycles for which method 1200 has been executed so far.

[0172] If the brake wear threshold is not reached, method 1200 proceeds to box 1210, and boxes 1202 to 1210 are repeated for the next predicted future use cycle.

[0173] In this way, the number of good future service cycles can be predicted based on whether the thermal oxidation threshold or the brake wear threshold is reached first. This is because once the first of these thresholds is reached, brake assembly 200 may require repair or replacement, or a component of brake assembly 200 may require repair or replacement. It should be understood that, for example, brake assembly 200 will not continue to be used if, instead of the brake wear threshold, it is reached. It should also be understood that the blocks of method 1200 can be performed in any suitable order. For example, block 1204 may be performed before block 1202, and / or block 1210 may be performed before block 1206.

[0174] One or more of the methods described above, namely methods 700, 800, 1100, 1200, or any variations thereof (e.g., real-time determination of oxidation or brake wear, or prediction of future thermal oxidation state or future brake wear, etc.), can be executed by the processor of the computing system 106 of the aircraft 100, for example, based on instructions stored in a computer-readable storage medium of the computing system 106. For example, monitoring of thermal oxidation state (after a usage cycle or in real time) can be performed by the processor of the computing system 106. Alternatively or additionally, monitoring of brake wear (after a usage cycle or in real time) can be performed by the processor of the computing system. Alternatively or in addition to any of these examples, predictions relating to future thermal oxidation state and / or future brake wear state can be performed by the processor of the computing system 106. These methods can be performed, for example, using data from instrument 108. For example, temperature data measured by temperature sensor 216 can be used. In the case of prediction, future temperature profiles and / or other predicted data can be predicted by the processor of the computing system 106. Alternatively, the data for prediction can be determined on a computing system not on the aircraft 100, and the data can be stored in a computer-readable storage medium of the computing system 106.

[0175] Instructions, in whole or in part, can be generated to perform the above-described process, and / or any suitable software or combination of software can be used to execute the process. In one example, "MATLAB" and / or "SCADE" can be used to generate all or part of the instructions for a given processor to perform any of the above-described processes. In other examples, other software packages can be used. For example, any suitable programming language, development environment, software package, etc., can be used. Other examples of programming languages ​​include Python, C++, C, JavaScript, FORTRAN, etc.

[0176] It should be noted that, unless otherwise expressly stated, the term "or" as used herein should be interpreted as meaning "and / or". Although the invention has been described above with reference to one or more preferred examples, it should be understood that various changes or modifications may be made without departing from the scope of the invention as defined by the appended claims.

Claims

1. An apparatus for an aircraft, the aircraft having one or more carbon aircraft wheel brakes and brake wear sensors, the brake wear sensors being configured to measure the wear condition of the brakes of the one or more carbon aircraft wheel brakes, the apparatus for the aircraft comprising a processor configured to: The number of future service cycles of the brake is determined based on the predicted condition of the brake, wherein... The predicted condition of the brake includes a predicted brake length value, which is determined based on the wear condition of the brake as measured by the brake wear sensor and an assumed thermal oxidation length of the brake, which is determined based on the thermal oxidation condition of the brake. Instructions on the determined number of future usage cycles will be provided to ground crew and / or the pilot of the aircraft. The number of future usage cycles refers to the number of usage cycles during which the brake is permitted to be used, and the usage cycle includes all use of the brake in relation to the flight conducted by the aircraft from departure to arrival; and The predicted brake length is less than the brake length determined by the measured wear condition.

2. The device for an aircraft according to claim 1, wherein, The predicted condition is the predicted future condition of the brake.

3. The device for an aircraft according to claim 1 or claim 2, wherein: The predicted condition also includes the predicted thermal oxidation state of the brake.

4. The device for an aircraft according to claim 3, wherein, The processor is configured to: The number of future use cycles is determined by predicting the number of future use cycles required for the predicted thermal oxidation state to reach the thermal oxidation threshold.

5. The apparatus for an aircraft according to claim 1 or claim 2, wherein: The predicted condition includes the predicted wear condition of the brake.

6. The device for an aircraft according to claim 5, wherein, The processor is configured to: The number of future use cycles is determined by predicting the number of future use cycles required for the predicted wear condition to reach the wear threshold.

7. The device for an aircraft according to claim 5, wherein, The processor is configured to: Determine the wear relationship between the wear condition of the brake and the number of service cycles of the brake; and The predicted wear state is determined based on the wear relationship.

8. The device for an aircraft according to claim 7, wherein, The processor is configured to: The wear relationship is determined based on one or more measured wear values.

9. The device for an aircraft according to claim 1, wherein, The processor is configured to: The thermal oxidation length is determined based on the brake's thermal oxidation state, the area of ​​the brake disc, and the mass loss indicated by the brake's original density.

10. The device for an aircraft according to claim 1 or claim 9, wherein, The processor is configured to: The predicted brake length value is determined by subtracting the thermal oxidation length from the wear value.

11. The device for an aircraft according to claim 1 or claim 9, wherein, The processor is configured to: The number of future use cycles is determined by predicting the number of future use cycles required for the predicted brake length value to reach the brake length threshold.

12. The device for an aircraft according to claim 11, wherein, The processor is configured to: Determine the brake length relationship between the brake length value and the number of service cycles of the brake; and The predicted brake length value is determined based on the brake length relationship.

13. The device for an aircraft according to claim 1 or claim 2, wherein, The processor is configured to: The predicted condition of the brake is compared with the condition of the brake determined based on one or more measurement characteristics of the brake.

14. The device for an aircraft according to claim 13, wherein, The processor is configured to: Based on the comparison, it is determined whether the brake alarm criteria are met; and Provides an indication that the brake alarm criteria are met.

15. An aircraft comprising: One or more aircraft wheel brakes; as well as The device for an aircraft according to any one of claims 1 to 14.

16. A method for determining the number of future service cycles of brakes on one or more carbon aircraft wheel brakes of an aircraft, said brakes including brake wear sensors configured to measure the wear condition of said brakes, the method comprising: The number of future service cycles of the brake is determined based on the predicted condition of the brake, wherein the predicted condition of the brake includes a predicted brake length value, the predicted brake length value being determined based on the wear condition of the brake measured by the brake wear sensor and the assumed thermal oxidation length of the brake, the assumed thermal oxidation length being determined based on the thermal oxidation condition of the brake. Instructions on the determined number of future usage cycles will be provided to ground crew and / or the pilot of the aircraft. The number of future usage cycles refers to the number of usage cycles during which the brake is permitted to be used, and the usage cycle includes all use of the brake in relation to the flight conducted by the aircraft from departure to arrival; and The predicted brake length is less than the brake length determined by the measured wear condition.

17. The method according to claim 16, wherein, The predicted condition is the predicted future condition of the brake.

18. The method according to claim 16 or claim 17, wherein: The predicted condition also includes the predicted thermal oxidation state of the brake.

19. The method of claim 18, comprising: The number of future use cycles is determined by predicting the number of future use cycles required for the predicted thermal oxidation state to reach the thermal oxidation threshold.

20. The method according to claim 16 or claim 17, wherein: The predicted condition includes the predicted wear condition of the brake.

21. The method of claim 20, comprising: The number of future use cycles is determined by predicting the number of future use cycles required for the predicted wear condition to reach the wear threshold.

22. The method of claim 20, comprising: Determine the wear relationship between the wear condition of the brake and the number of service cycles of the brake; and The predicted wear state is determined based on the wear relationship.

23. The method of claim 22, comprising: The wear relationship is determined based on one or more measured wear values.

24. The method of claim 16, further comprising: The thermal oxidation length is determined based on the brake's thermal oxidation state, the area of ​​the brake disc, and the mass loss indicated by the brake's original density.

25. The method according to claim 16 or claim 24, further comprising: The number of future use cycles is determined by predicting the number of future use cycles required for the predicted brake length value to reach the brake length threshold.

26. The method of claim 25, comprising: Determine the relationship between the brake length value and the number of service cycles of the brake; and The predicted brake length value is determined based on the brake length relationship.

27. The method according to claim 16 or claim 17, comprising: The predicted condition of the brake is compared with the condition of the brake determined based on one or more measurement characteristics of the brake.

28. The method of claim 27, comprising: Based on the comparison, it is determined whether the brake alarm criteria are met; and Provides an indication that the brake alarm criteria are met.

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