Brake control

Abstract

An apparatus is disclosed, comprising a controller configured to generate a first indication for a vehicle braking system based on the oxidation state of wheel brakes of a vehicle. A braking system is also disclosed, comprising a controller configured to receive a first indication generated based on the oxidation state of wheel brakes of a vehicle; and to control operation of the brakes based on the first indication. A method for controlling at least one brake of an aircraft is also disclosed, as well as an aircraft including the apparatus, the braking system, and a temperature sensor configured to measure the temperature of the aircraft's wheel brakes and transmit the temperature measurement value to the apparatus.

Description

Technical Field

[0001] The present invention relates to brake control, and specifically, but not exclusively, to brake control taking into account the state of the brake, such as an oxidized state. Background Technology

[0002] Vehicle brakes may include components such as brake discs made of carbon-carbon composite materials. Brakes may undergo thermal oxidation at high temperatures because carbon atoms in the brake disc react with oxygen. For the safe operation of the vehicle, once a certain amount of thermal oxidation has occurred, the brakes may need to be repaired or replaced. Summary of the Invention

[0003] A first aspect of the invention provides an apparatus comprising: a controller configured to generate a first indication for a vehicle braking system based on the oxidation state of a wheel brake of a vehicle.

[0004] Optionally, the controller is configured to determine the brake temperature characteristic standard of the brake based on the oxidation state of the brake; determine whether the temperature characteristics of the brake meet the brake temperature characteristic standard; and generate a first indication for the braking system based on whether the brake temperature characteristics meet the brake temperature characteristic standard.

[0005] Optionally, the controller receives an indication of the temperature characteristics of the brake from a temperature sensor associated with the brake.

[0006] Optionally, the controller receives the predicted temperature characteristics from the brake temperature prediction function as the temperature characteristics of the brake.

[0007] Optionally, the controller is configured to: monitor the temperature characteristics of the brake; if the temperature characteristics of the brake no longer meet the brake temperature characteristic standard, generate a second indication for the braking system in which the temperature characteristics of the brake no longer meet the brake temperature characteristic standard.

[0008] Optionally, the temperature characteristics of the brake include the temperature of the brake; and if the temperature of the brake exceeds the brake temperature threshold, the brake temperature characteristic standard is met.

[0009] Optionally, the controller is configured such that the higher the thermal oxidation level of the brake, the lower the brake temperature threshold of the determined brake temperature characteristic standard.

[0010] Optionally, if the thermal oxidation state of the brake is lower than a predetermined thermal oxidation level, a first brake temperature characteristic standard including a first temperature threshold is selected.

[0011] Optionally, if the thermal oxidation state of the brake is higher than a predetermined thermal oxidation level, a second brake temperature characteristic standard including a second temperature threshold is selected, wherein the second temperature threshold is lower than the first temperature threshold.

[0012] Optionally, a second brake temperature characteristic criterion may be selected based on the difference between the brake's thermal oxidation state and a predetermined thermal oxidation level.

[0013] Optionally, the first temperature threshold is higher than 400°C.

[0014] A second aspect of the invention provides a braking system for a vehicle, the braking system including a controller configured to: receive a first instruction generated based on the oxidation state of wheel brakes of the vehicle; and control the operation of the brakes based on the first instruction.

[0015] Optionally, in the braking system according to the second aspect, the first indication received by the controller is generated based on whether the brake temperature characteristics meet the brake temperature characteristic standard; and the controller is configured to: receive a second indication that the brake temperature characteristics no longer meet the brake temperature characteristic standard; and selectively control the brake to be enabled or disabled based on the received indication.

[0016] Optionally, in the braking system according to the second aspect, the controller is configured to disable the brakes if a first instruction is received.

[0017] Optionally, in the braking system according to the second aspect, the controller is configured to activate the brakes if a second instruction is received.

[0018] Optionally, in the braking system according to the second aspect, the vehicle is an aircraft, and the controller is configured to disable the brakes if a taxiing criterion is met, wherein the taxiing criterion includes one or more of the following: an aircraft speed threshold, which is defined such that an aircraft speed less than or equal to the aircraft speed threshold meets a predefined taxiing criterion; and a specific flight phase indicated by the aircraft's flight phase indication system.

[0019] Optionally, in the braking system according to the second aspect, the controller is configured to: receive a braking request, the braking request including information related to the requested braking intensity; determine, based on the information related to the requested braking intensity, whether the requested braking intensity exceeds a braking intensity threshold; and if the requested braking intensity exceeds the braking intensity threshold, activate at least one disabled brake.

[0020] A third aspect of the invention provides a method for controlling at least one brake of an aircraft, the method comprising: generating a first indication based on the oxidation state of a wheel brake of the aircraft; and controlling the brake to be disabled based on the first indication.

[0021] Optionally, the method according to the third aspect includes: determining the brake temperature characteristic standard of the brake based on the thermal oxidation state of the brake; determining whether the temperature characteristics of the brake meet the brake temperature characteristic standard; and generating a first indication based on whether the brake temperature characteristics meet the brake temperature characteristic standard.

[0022] Optionally, the method according to the third aspect includes: (i) monitoring the temperature characteristics of the brake; (ii) determining whether the temperature characteristics of the brake still meet the brake temperature characteristic standard; if the temperature characteristics of the brake no longer meet the brake temperature characteristic standard, then: generating a second indication that the temperature characteristics of the brake no longer meet the brake temperature characteristic standard; and controlling the brake to be enabled based on the second indication; and repeating (i) and (ii) if the temperature characteristics of the brake still meet the brake temperature characteristic standard.

[0023] Optionally, the method according to the third aspect includes receiving an indication of the temperature characteristics of the brake from a temperature sensor associated with the brake.

[0024] Optionally, the method according to the third aspect includes receiving the predicted temperature characteristics as the temperature characteristics of the brake from the brake temperature prediction function.

[0025] Optionally, in the method according to the third aspect, the temperature characteristics of the brake include the temperature of the brake; and if the temperature of the brake exceeds the brake temperature threshold, the brake temperature characteristic standard is satisfied.

[0026] Alternatively, in the method according to the third aspect, the higher the thermal oxidation level of the brake, the lower the brake temperature threshold of the determined brake temperature characteristic standard.

[0027] Optionally, in the method according to the third aspect, if the thermal oxidation state of the brake is lower than a predetermined thermal oxidation level, a first brake temperature characteristic criterion including a first temperature threshold is selected.

[0028] Optionally, in the method according to the third aspect, if the thermal oxidation state of the brake is higher than a predetermined thermal oxidation level, a second brake temperature characteristic standard including a second temperature threshold is selected, the second temperature threshold being lower than the first temperature threshold.

[0029] Optionally, in the method according to the third aspect, a second brake temperature characteristic criterion is selected based on the difference between the brake's thermal oxidation state and a predetermined thermal oxidation level.

[0030] Optionally, in the method according to the third aspect, the first temperature threshold is higher than 400°C.

[0031] Optionally, in the method according to the third aspect, the brakes are disabled if a predefined taxiing criterion is met, wherein the predefined taxiing criterion includes one or more of the following: an aircraft speed threshold defined such that an aircraft speed less than or equal to the aircraft speed threshold satisfies the predefined taxiing criterion; and a specific flight phase indicated by the aircraft's flight phase indication system.

[0032] Optionally, the method according to the third aspect includes: receiving a braking request, the braking request including information related to the requested braking intensity; determining, based on the information related to the requested braking intensity, whether the requested braking intensity exceeds a braking intensity threshold; and if the requested braking intensity exceeds the braking intensity threshold, activating at least one disabled brake.

[0033] A fourth aspect of the present invention provides an aircraft comprising: an apparatus according to the first aspect; a braking system according to the second aspect; and a temperature sensor configured to measure the temperature of the aircraft's wheel brakes and transmit the temperature measurement value to the apparatus. Attached Figure Description

[0034] Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, wherein:

[0035] Figure 1 This is a schematic diagram of an example aircraft that can be deployed on it;

[0036] Figure 2 It is a schematic diagram of the brakes and wheels of the landing gear of an aircraft, based on the example.

[0037] Figure 3 It is a schematic diagram of the device and braking system of the example vehicle;

[0038] Figure 4a This is a first flowchart of a method for controlling at least one brake of an aircraft according to an example;

[0039] Figure 4b This is a second flowchart of a method for controlling at least one brake of an aircraft, based on an example;

[0040] Figure 4c This is a third flowchart of a method for controlling at least one brake of an aircraft according to an example; and

[0041] Figure 5 This is the fourth flowchart of a method for controlling at least one brake of an aircraft according to an example.

[0042] Figure 6 This is a flowchart of an exemplary method for determining the thermal oxidation state of the brakes of an aircraft landing gear;

[0043] Figure 7 This is a flowchart of an exemplary method for determining the thermal oxidation state of the brakes of an aircraft landing gear;

[0044] Figure 8 This is an exemplary graph illustrating the temperature of the brake relative to time.

[0045] Figure 9 This is an exemplary graph illustrating the thermal oxidation state of a brake relative to time at a specific temperature.

[0046] Figure 10 This is an exemplary flowchart of a method for determining brake wear based on an example; and

[0047] Figure 11 This is an exemplary flowchart based on an example of a method for predicting multiple good future usage cycles of an aircraft brake. Detailed Implementation

[0048] The following disclosure relates to systems and processes for limiting the use of brakes in vehicles, such as aircraft brakes, when they reach certain high temperatures for the purpose of reducing thermal oxidation during use.

[0049] Figure 1 This 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 instruments 108, such as instruments or sensors for measuring characteristics or parameters related to the aircraft, and instruments or sensors for measuring environmental characteristics. It should be understood that in some examples, instruments 108 may be distributed at various different locations within aircraft 100.

[0050] Figure 2This is a simplified schematic diagram of a brake 200 associated with a wheel 104 of an aircraft 100. Each wheel of the aircraft 100 may have an associated brake, such as brake 200. The brake 200 applies braking force to suppress 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 an 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 is pushed against 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.

[0052] Any one or more of the rotor, stator, pressure plate 204, and reaction plate 206 may be made of carbon-carbon (CC) composite material. A brake including a brake disc made of CC composite material can be referred to as a carbon brake. For example, brake disc 202 may be made of a carbon fiber reinforced graphite matrix. During use, brake disc 202 may undergo oxidation. During the oxidation reaction, oxygen reacts with the carbon in brake disc 202, causing carbon atoms to be removed from brake disc 202, resulting in mass loss due to the production of carbon dioxide and / or carbon monoxide. 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 assisted by a catalyst. For example, alkali metals are known catalysts for the oxidation of CC composites. Catalytic oxidation may be relevant in areas with relatively high salinity to air. It may also be relevant at airports using runway de-icing agents containing alkali metal salts. Thermal oxidation of brake disc 202 may occur if it reaches high temperatures. During use, brake 200, particularly brake disc 202, can 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 assembly 200, causing its temperature to rise. In this example, the components of brake 200, which are made of CC composite material (i.e., brake disc 202), undergo oxidation. However, the present disclosure below relates to the oxidized state of brake 200.

[0054] The aircraft 100 may include a braking system 214 that controls the operation of the brake 200. The braking system 214 causes the brake 200 to be applied in response to a braking request (e.g., when the pilot of the aircraft 100 presses the brake pedal). For example, the brake 200 may be hydraulically actuated or electrically actuated, and the braking system 214 may control a brake actuation system (not shown) to apply the brake 200. The braking system 214 may communicate with the brake actuation system via a wireless or wired communication link.

[0055] Figure 3 This is a simplified schematic diagram of device 300 and braking system 214. Device 300 includes controller 302. Controller 302 is configured to generate a first indication for braking system 214 based on the oxidation state of brake 200. For example, device 300 can be mounted on a vehicle such as aircraft 100 to generate the first indication in relation to brake 200. Device 300 can be mounted on any type of vehicle including one or more wheels with brakes. However, for convenience, the following description will be performed in the context of aircraft 100.

[0056] exist Figure 3In the example, braking system 214 includes controller 304. For clarity, the controller 302 of device 300 will be referred to as first controller 302, and the controller 304 of braking system 214 will be referred to as second controller 304. Second controller 304 is configured to: receive a first indication generated based on the oxidation state of brake 200 (as described above); and control the operation of brake 200 based on the first indication. Second controller 304 may receive the indication from first controller 302 via a wired or wireless communication link. Alternatively, first controller 302 may write information relating to the indication to a computer-readable storage medium (not shown), and second controller 304 may read information relating to the indication from said computer-readable storage medium.

[0057] The second controller 304 can be configured to disable the brake 200 if it receives a first instruction. For example, if the brake 200 is disabled, the second controller 304 can assign it a "disabled" state. Disabling the brake 200 means that when the braking system 214 receives a braking request, the braking system 214 will not cause the brake 200 to be applied. Instead, the requested braking can be provided by other brakes associated with the other wheels of the landing gear 102.

[0058] Figure 4a The flowchart illustrates the operation of the first controller 302 and the second controller 304. Figure 4a The flowchart illustrates an example method 400 for controlling at least one brake of an aircraft 100. Method 400 may be implemented by first and second controllers 302, 304. In some examples, the processing block of method 400 may be provided as processor-executable instructions (e.g., executable by the respective processors of the first and second controllers 302, 304).

[0059] At block 402, a first indication is generated based on the oxidation state of the brake 200. The first controller 302 of the device 300 executes block 402. At block 402, for example, the first controller 302 receives information about the oxidation state of the brake 200 (the source of the information is described in further detail below). The first controller 302 may compare this oxidation state with a specific threshold, or may determine a criterion based on the oxidation state and compare certain characteristics of the brake 200 with that criterion. This comparison is described in further detail below. The first controller 302 may generate the first indication based on this comparison. If the first indication is generated, method 400 proceeds to block 404.

[0060] At box 404, brake 200 is controlled to be disabled based on the first instruction.

[0061] In some examples, the oxidation state of brake 200 can be considered as either thermal oxidation (i.e., the oxidation state can be thermal oxidation) or catalytic oxidation (i.e., the oxidation state can be catalytic oxidation). In some examples, both thermal oxidation and catalytic oxidation can be considered. In the following examples, the oxidation state of brake 200 is considered only as thermal oxidation.

[0062] In some examples, the thermal oxidation state of brake 200 can be determined using the methods and systems described in a previously unpublished application appended herein, namely GB patent application number 1803203.7. For example, the thermal oxidation state of brake 200 after a braking event / operation can be determined using a thermal oxidation model based on the initial thermal oxidation state of brake 200 before the braking event and a temperature profile of brake 200 over time. A first controller 302 can receive the thermal oxidation state of brake 200 from the means for determining the thermal oxidation state of brake 200. Alternatively, the latest 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 the first controller 302 can retrieve the thermal oxidation state of brake 200 from said computer-readable storage medium. Each time the thermal oxidation state is updated, the first controller 302 can retrieve the thermal oxidation state of brake 200. In some examples, the first controller 302 can determine the thermal oxidation state of brake 200 as described in the previously unpublished application.

[0063] As described, the oxidation state can be represented as the amount of mass loss due to oxidation. In some examples, the first controller 302 can compare the oxidation state of the brake 200 with an oxidation threshold, and if the oxidation threshold is reached, a first indication can be generated. For example, the oxidation threshold can be between 4% and 6.5% of the original mass of the brake 200 due to oxidation, such as 5.7%. In the example with an oxidation threshold of 5.7%, if the thermal oxidation state reaches (i.e., equal to or greater than) 5.7% of the original mass of the brake 200, the oxidation criterion can be met. In such an example, if the brake 200 is oxidized beyond a certain level, the brake 200 can be disabled. The oxidation threshold can be set at a level at which overall or partial repair or replacement of the brake 200 is considered necessary for safe operation.

[0064] Alternatively or additionally, the first controller 302 may determine a brake temperature characteristic criterion for the brake 200 based on the oxidation state of the brake 200. The first controller 302 may determine whether the temperature characteristics of the brake 200 meet the temperature characteristic criterion and generate a first indication for the braking system 214 based on whether the brake temperature characteristics meet the criterion. In an example where an oxidation threshold is also used and the oxidation state of the brake 200 reaches the oxidation threshold, the first controller 302 may not compare the temperature characteristics with the temperature characteristic criterion. This is because, in such an example, the brake 200 can simply be disabled because it is too oxidized to be relevant to the temperature characteristics of the brake 200. The examples described below are performed in the context of the first controller 302 comparing the temperature characteristics with the temperature characteristic criterion.

[0065] Figure 4b A specific example of method 400 is shown, in which a brake temperature characteristic standard is determined and used to generate a first indication. Figure 4b Boxes 402a to 402c shown can be used as Figure 4a A portion of block 402 is executed, for example, by the first controller 302. At block 402a, a brake temperature characteristic criterion is determined based on the oxidation state of the brake 200. At block 402b, it is determined whether the temperature characteristics of the brake 200 meet the brake temperature characteristic criterion. At block 402b, for example, the first controller 302 receives the temperature characteristics of the brake 200 (the source of the brake temperature is described in further detail below). For example, the first controller 302 compares the brake temperature characteristics received by the first controller 302 with the brake temperature characteristic criterion determined at block 402a to determine whether the brake temperature characteristic criterion is met. If the brake temperature characteristic criterion is met, the process proceeds to block 402c.

[0066] At block 402c, a first indication is generated based on whether the brake temperature characteristic criterion is met. If the brake temperature characteristic criterion is met, the first indication is generated. Conversely, if the brake temperature characteristic criterion is not met at block 402b, the method terminates and no indication is generated. However, block 402b can be executed again when updated brake temperature characteristics become available. If the thermal oxidation state of brake 200 changes, the method according to any of the described examples can be repeated.

[0067] At block 404, brake 200 is controlled to be disabled based on a first indication generated at block 402c. For example, second controller 304 may be configured to receive a first indication generated based on whether brake temperature characteristics meet brake temperature characteristic criteria. For example, as described, if a first indication is generated, second controller 304 may receive the first indication and may disable brake 200.

[0068] The first controller 302 can be configured to monitor the temperature characteristics of the brake, and generate a second indication for the braking system 214 if the temperature characteristics of the brake 200 no longer meet the brake temperature characteristic standard. Figure 4c This is a flowchart illustrating additional processing blocks that can form part of method 400. For example, method 400 can proceed from block 404 to block 406. At block 406, the temperature characteristics of the brake are monitored. For example, a measured value of the temperature characteristics as a function of time can be received by the first controller 302. At block 408, it is determined whether the temperature characteristics of the brake 200 still meet the brake temperature characteristic criterion. For example, the first controller 302 compares the latest value of the brake temperature characteristics with the brake temperature characteristic criterion. If the temperature characteristics of the brake no longer meet the brake temperature characteristic criterion, then at block 410, the first controller 302 generates a second indication that the temperature characteristics of the brake no longer meet the brake temperature characteristic criterion.

[0069] The second controller 304 can be configured to receive a second indication that the temperature characteristics of the brake no longer meet the brake temperature characteristic standard, and selectively control the brake to be enabled or disabled based on the received indication. As previously described, if the second controller 304 receives a first indication, the second controller 304 can disable the brake 200. If the second controller 304 receives a second indication, the second controller 304 can control the brake 200 to be enabled. At block 412, the brake 200 is controlled to be enabled based on the second indication. For example, if the brake 200 is disabled and the temperature characteristics of the brake 200 no longer meet the brake temperature characteristic standard, the second controller 304 can change the state of the brake 200 from "disabled" to "enabled". The brake 200, when enabled, can again be controlled by the braking system 214 to provide braking in response to a braking request.

[0070] On the other hand, if the brake temperature characteristics criteria, as determined in box 408, are still met, the process returns to box 406 to continue monitoring the temperature characteristics of the brake 200, and boxes 406 and 408 are repeated.

[0071] The brake temperature characteristic criterion depends on the brake's oxidation state. In the example described below, the brake temperature characteristic criterion depends on the thermal oxidation state of brake 200. Therefore, brake 200 can be disabled sooner or later (due to the temperature rise caused by braking) depending on its thermal oxidation state, as further explained below. Managing braking in this way to suppress thermal oxidation of brake 200 can extend the life of brake 200.

[0072] The temperature characteristics of the brake may include the temperature of the brake 200 (i.e., the current temperature). Specifically, the temperature of the brake 200 may be the temperature of the brake disc 202 made of CC composite material, as described. It should be understood that the temperature of the component made of CC composite material is relevant when controlling the brake 200 to suppress thermal oxidation, because the component made of CC composite material undergoes thermal oxidation. In some examples, the temperature characteristics may also include the rate of temperature increase of the brake 200.

[0073] If the temperature of brake 200 exceeds the brake temperature threshold, the brake temperature characteristic standard can be met. The first controller 302 can be configured such that the higher the level of thermal oxidation of brake 200, the lower the brake temperature threshold of the determined brake temperature characteristic standard. In such an example, if brake 200 has undergone significant thermal oxidation, the braking system 214 can disable brake 200 when it reaches a lower temperature compared to brakes with less thermal oxidation.

[0074] In some examples, the brake temperature characteristic criterion may alternatively or additionally include a temperature increase rate threshold. In such examples, where the temperature characteristic includes the temperature increase rate of brake 200, the brake temperature characteristic criterion can be met if the temperature increase rate of brake 200 exceeds the temperature increase rate threshold. The following example is described in the context of the temperature characteristic including the temperature of brake 200 and the brake temperature characteristic criterion being met if the temperature of brake 200 exceeds the brake temperature threshold.

[0075] In some examples, the thermal oxidation state of brake 200 can be compared to a predetermined thermal oxidation level. In such an example, if the thermal oxidation state of brake 200 is lower than the predetermined thermal oxidation level, the first controller 302 selects a first brake temperature characteristic criterion that includes a first temperature threshold. The first temperature threshold can be relatively high, allowing brake 200 to become relatively hot before being disabled by braking system 214, but not so hot that significant thermal oxidation exists for a considerable period of time.

[0076] For some brakes, thermal oxidation can be expected to occur at a relatively low rate above 400°C and at a relatively high rate above 750°C. Below 400°C, there may be no significant thermal oxidation. Therefore, the first temperature threshold can be higher than 400°C. For such brakes, setting a first temperature threshold of, for example, 600°C would allow the brake to be used at relatively high temperatures without the risk of the temperature reaching a level where a relatively high rate of thermal oxidation exists.

[0077] If the thermal oxidation state of brake 200 is higher than a predetermined thermal oxidation level, the first controller 302 can select a second brake temperature characteristic criterion that includes a second temperature threshold lower than a first temperature threshold. Therefore, when the thermal oxidation state of brake 200 is higher than the predetermined thermal oxidation level, brake 200 is disabled at a lower temperature. This prevents brake 200 from being exposed to such high temperatures when the thermal oxidation state of brake 200 becomes premature, thus further suppressing thermal oxidation and extending the life of brake 200.

[0078] In some examples, the second temperature threshold may be 400°C. In some examples, the second brake temperature characteristic criterion may be selected based on the difference between the thermal oxidation state of brake 200 and a predetermined thermal oxidation level. For example, the higher the thermal oxidation level of brake 200, the lower the second temperature threshold may be. For example, the second temperature threshold may be a value below 600°C and may decrease as the thermal oxidation state of brake 200 continues to increase above the predetermined thermal oxidation level.

[0079] The first controller 302 can determine the brake temperature characteristic standard by using the thermal oxidation state of the brake 200 as input to an algorithm for determining the brake temperature characteristic standard. This algorithm can take into account the physical characteristics of the brake 200. For example, this could be the case where the brake 200 undergoes thermal oxidation at a high rate at a temperature below 750°C. In such an example, the first temperature threshold can be set below 600°C. The first controller 302 can implement instructions stored on a computer-readable storage medium (e.g., included in the computing system 106) to execute the algorithm. In some examples, the first controller 302 can access (from its accessed computer-readable storage medium) a lookup table storing the thermal oxidation state of the brake 200 and the corresponding predetermined brake temperature characteristic standard. The first controller 302 can use the lookup table to determine the brake temperature characteristic standard. In some examples, the first controller 302 can be configured to generate such a lookup table using an algorithm of the aforementioned type.

[0080] As described, thermal oxidation of the brake disc 202 can occur at high temperatures. Once the oxidation state of the brake 200 reaches a certain level, it may be necessary to repair or replace the brake 200 of the aircraft 100 to ensure safe operation. As described, if the oxidation threshold is reached, it may be necessary to repair or replace the brake 200 of the aircraft 100. When the thermal oxidation state of the brake 200 approaches the oxidation threshold (e.g., a loss of 4% to 6.5% of the original mass of the brake 200), a predetermined thermal oxidation level can be set below the oxidation threshold to suppress thermal oxidation.

[0081] In order to compare the temperature characteristics of brake 200 with a defined brake temperature characteristic standard and to monitor the temperature characteristics of brake 200, the first controller 302 can receive information about the temperature characteristics of brake 200 from the temperature sensor 216 associated with brake 200 (see...). Figure 2 Temperature sensor 216 can be configured to make thermal contact with one of the brake discs. Figure 2 In this example, temperature sensor 216 is disposed on stator 210. In this example, stator 210 is the brake disc that may reach the highest temperature. Temperature sensor 216 can be any type of temperature sensor suitable for aircraft brake assemblies. For example, temperature sensor 216 is capable of operating normally within the temperature range that brake disc 202 may reach. For example, temperature sensor 216 can be a thermocouple, surface acoustic wave (SAW) sensor, eddy current sensor, resistive thermal sensor, strain gauge, etc. First controller 302 can receive brake temperature measurements from temperature sensor 216 via a wired or wireless communication link. If the temperature sensor is disposed on a portion of brake 200 other than one of 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.

[0082] The first controller 302 can receive brake temperature measurements from the temperature sensor 216 in real time. The first controller 302 can continuously receive brake temperature measurements, or alternatively, can periodically receive discrete brake temperature information items. In some examples, the controller 302 can request and receive brake temperature measurements from the temperature sensor 216 in response. The rate of temperature increase of the brake 200 can be determined based on at least two temperature measurements at different times.

[0083] The first controller 302 can receive the predicted temperature characteristics as the temperature characteristics of the brake 200 from the brake temperature prediction function. The brake temperature prediction function can predict the temperature of the brake 200 based on the energy input to the brake 200 during a braking event. A braking event is, for example, an event involving one or more applications of the brake 200. Using the energy input to the brake 200, the mass of the brake 200, and the specific heat capacity of the brake 200, the temperature change of the brake 200 caused by the input energy can be determined. The temperature of the brake 200 can then be determined using the temperature change, i.e., by adding it to the initial temperature of the brake 200. The initial temperature before the braking event can be known from previous iterations of this calculation. On the other hand, if the energy input is expected to be the first braking application of the day (i.e., the brake 200 has not been applied for a long time), the initial temperature can be considered as the ambient temperature.

[0084] In some examples, a brake thermal model (e.g., a computational fluid dynamics model) can be used to predict the temperature of brake 200 given the amount of energy input to brake 200. For example, the physical properties of brake 200 (e.g., mass, heat capacity, etc.), environmental characteristics, and the energy input to brake 200 can be fed into the brake thermal model, and the brake thermal model can output a predicted temperature of brake 200. Environmental characteristics may include (e.g., ambient temperature near brake 200), wind conditions, or other characteristics that may affect the temperature of brake 200. Environmental characteristics can be measured by instruments included, for example, in instrument 108.

[0085] In some examples, the rate of temperature increase of brake 200 can be predicted using a brake temperature prediction function based on the energy input to brake 200. For instance, a brake thermal model can be used to predict the rate of increase based on the energy input to the brake and the physical properties of brake 200.

[0086] As described, the thermal oxidation state of brake 200 is related to the amount of mass of brake 200 due to thermal oxidation, which can be taken into account when determining the mass of brake 200. Mass loss due to wear of brake disc 202 can also be taken into account. For example, instrument 108 may include a brake wear sensor associated with brake 200. The brake wear sensor can provide an indication of a reduction in the length L of brake disc 202. Using the reduction in length L due to wear, the reduction in the mass of brake 200 due to wear can be determined. In some examples, the mass of brake 200 can be determined by subtracting the amount of mass loss due to thermal oxidation and the amount of mass loss due to brake wear from the initial mass of brake 200 (e.g., specified by the brake manufacturer or measured when brake 200 is installed in aircraft 100).

[0087] The energy input to brake 200 can be determined using measurements from instruments included in instrument 108. Instrument 108 may include a torque sensor for measuring the torque reacted by brake 200 and a tachometer for measuring the rotational speed of wheel 104. In such an example, the energy input to brake 200 is calculated by integrating the product of wheel speed and torque over time.

[0088] If, for example, temperature sensor 216 malfunctions or the first controller 302 cannot receive a brake temperature measurement from temperature sensor 216, the first controller 302 can receive a predicted temperature. In some examples, a processor (e.g., the processor of computing system 106) can determine whether to provide the first controller 302 with either a brake temperature measurement from temperature sensor 216 or a predicted temperature from a brake temperature prediction function. In some examples, the first controller 32 can receive both a brake temperature measurement from temperature sensor 216 and a predicted temperature from a brake temperature prediction function and determine which temperature value to use. For example, if the two values ​​differ significantly, the temperature value closest to the one likely to be expected given the mass, speed, etc., of aircraft 100 can be used.

[0089] During the use of aircraft 100, there may be situations where it is undesirable to disable one or more brakes of aircraft 100. For example, it may be desirable to use all brakes during landing to reduce the speed of aircraft 100. The second controller 304 can be configured to disable the brakes if taxiing criteria are met. In such an example, brake 200 may be disabled only during the taxiing phase defined by the taxiing criteria in response to the second controller 304 receiving a first instruction.

[0090] Taxiing criteria may include one or more of the aircraft speed threshold and specific flight phases of aircraft 100. An aircraft speed threshold can be defined such that aircraft speeds less than or equal to the threshold satisfy the taxiing criteria. For example, the aircraft speed threshold could be 30 knots. In such an example, if the aircraft speed is higher than 30 knots, the second controller 304 does not disable brakes 200 upon receiving the first instruction. This is because at higher speeds, greater braking force may be required to reduce the speed of aircraft 100 over a certain time or distance. The second controller may receive information related to aircraft speed from onboard instruments (i.e., instruments included in instrument 108) or the processor of computing system 106.

[0091] A specific flight phase can be indicated by the flight phase indication system of the aircraft 100. A specific flight phase can be, for example, a taxiing phase after landing and / or a taxiing phase before takeoff. The flight phase indication system can be implemented at least in part by the computing system 106 of the aircraft 100. In such an example, the second controller 304 does not disable the brake 200 unless the flight phase is indicated as a taxiing phase after landing and / or a taxiing phase before takeoff. By disabling the brake 200 in response to the first indication only when the aircraft is in a taxiing phase defined by the taxiing criteria, the brake 200 can be used to provide braking during other phases that prioritize reducing the speed of the aircraft 100 over protecting the brake 200 from thermal oxidation.

[0092] As described, braking system 214 causes brake 200 to be applied in response to a braking request. A second controller 304 of braking system 214 may be configured to receive a braking request when the pilot of aircraft 100 presses the brake pedal. The braking request may include information relating to the requested braking intensity. For example, the braking request may include information about the force / distance with which the pilot depresses the brake pedal.

[0093] In some situations, heavy braking may be required. For example, a pilot may forcefully press the brake pedal to bring aircraft 100 to an immediate stop or significantly reduce its speed over a short period. In such cases, it may not be desirable to disable any of aircraft 100's brakes to provide sufficient braking. The second controller 304 may determine, based on information related to the requested braking intensity, whether the requested braking intensity exceeds a braking intensity threshold. If the requested braking intensity exceeds the braking intensity threshold, the second controller 304 may activate at least one disabled brake. For example, if brake 200 has already been disabled in response to a first indication, the second controller 304 may activate brake 200 in response to the requested braking intensity exceeding the braking intensity threshold.

[0094] Figure 5This is a flowchart illustrating a method 500 executed by a second controller 304 to activate a disabled brake in response to a braking request with a high braking intensity. At block 502, a braking request including information relating to the requested braking intensity is received. For example, as described, the second controller 304 receives the braking request. At block 504, the second controller 304 determines, based on the information relating to the requested braking intensity, whether the requested braking intensity exceeds a braking intensity threshold. If the requested braking intensity exceeds the braking intensity threshold, method 500 proceeds to block 506 and at least one disabled brake is activated. For example, if brake 200 was previously disabled in response to a first indication, brake 200 can be activated by the second controller 304 at block 506. In this way, depending on the requested braking intensity, if a relatively high braking intensity is required, brake 200 can be reactivated to provide braking.

[0095] On the other hand, if the requested braking intensity does not exceed the braking intensity threshold, method 500 terminates. Method 500 can be repeated each time a braking request is made, so that the requested braking intensity can be provided.

[0096] During aircraft operation, all or part of the described methods can be executed in real time. For example, the described methods can be executed in real time when the aircraft 100 is in a taxiing phase and / or when a braking event occurs. For example, the temperature characteristics of the brake 200 can be repeatedly compared with a brake temperature characteristic standard. For example, during a braking event, the first controller 302 can repeatedly determine whether the temperature characteristics of the brake 200 meet the brake temperature characteristic standard. The second controller 304 can control the described brake 200 in real time based on this determination. For example, the second controller 304 can receive an instruction each time it is determined that the brake temperature characteristic standard is met or no longer met (i.e., the second controller 304 can receive first and second instructions in real time as appropriate) and selectively control the brake 200 to be enabled or disabled according to the received instructions.

[0097] For example, all or part of the described method can be executed rapidly and repeatedly, wherein the temperature of the brake 200 is sampled multiple times per second, up to the sampling rate of the temperature sensor.

[0098] Figure 6An exemplary method 600 for determining the thermal oxidation state of a brake, such as a flight brake assembly 200, of an aircraft landing gear assembly 102 is summarized. Method 600 includes using a thermal oxidation model to determine the thermal oxidation state of the brake assembly 200 after the 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 the brake assembly 200 after the braking event is also referred to as the updated thermal oxidation state. This is because the thermal oxidation state of the brake assembly 200 after the braking event takes into account the change in the initial thermal oxidation state caused by the braking event.

[0099] 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.

[0100] At block 602 of method 600, 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.

[0101] 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.

[0102] 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 600. 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 600 or other methods disclosed herein.

[0103] At block 604 of method 600, 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 600 may be performed in the field during the service life of aircraft 100. In the case of performing method 600 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 604, 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.

[0104] 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 600 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.

[0105] In an example of a temperature profile for the entire service life of the aircraft 100, method 600 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.

[0106] In method 600, 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.

[0107] Figure 7 This is a flowchart illustrating method 700, which can be performed as part of method 600. For example, method 700 relates to a more specific example of block 604 of method 600. Block 702 is identical to block 602 of method 600, 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 704, 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.

[0108] In box 706, it is determined whether one or more temperature criteria are met. For example, if no temperature threshold is exceeded, method 700 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.

[0109] 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 700 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.

[0110] 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 708 of method 700. 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 8 The identification of high-temperature events is described. Figure 8 This is a graph illustrating a portion of an example temperature curve. Figure 8 In the graph, the vertical axis represents the temperature of the brake assembly 200, while the horizontal axis represents time. In this example, the curve portion 802 indicates that the temperature of the brake assembly 200 exceeds a first temperature threshold 804 and a second temperature threshold 806. In this example, a high-temperature event is identified as the portion of curve 802 above the second temperature threshold 806, because the second temperature threshold 806 is the highest temperature threshold exceeded.

[0111] Compared to thermal oxidation occurring above the first temperature threshold 804 but below the second temperature threshold 806, the amount of thermal oxidation occurring above the second temperature threshold 806 can be significantly greater over a given interval. Therefore, in this example, the portion of the temperature curve below the second temperature threshold 806 is not considered. In other examples, for example, when method 700 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 8 The curve is merely an illustrative example for purposes of explanation.

[0112] At box 710, 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 8 In the example, the high-temperature interval is defined as time interval 808.

[0113] At box 712, a high-temperature event value for the brake assembly 200 is determined for a high-temperature interval. The high-temperature event value is the temperature attributed to the 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.

[0114] At box 714, 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 as shown in Equation 1 below:

[0115]

[0116] In Formula 1, 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 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 Formula 1 is set to the high-temperature event value for the purposes of box 714. In this example, the thermal oxidation rate k(T) is the oxidation parameter determined at box 714. Activation energy E A The values ​​of the pre-exponential constant A depend on the physical properties of the CC compound of the brake assembly 200 (in this example, brake disc 202). 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 the 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.

[0117] 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 implementing method 700. A The appropriate value for the pre-exponential factor A.

[0118] Figure 9 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 9The vertical axis of the graph represents a measurement 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 902 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.

[0119] In this example, the thermal oxidation state Ox changes over time in a different manner below thermal oxidation state level 904 than it does above thermal oxidation state level 904. 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 904 and to change approximately linearly over time above oxidation state level 904. In this example, the thermal oxidation state increases at an accelerating rate over time until it reaches thermal oxidation state level 904. After reaching thermal oxidation state level 904, the rate of change of the thermal oxidation state Ox over time remains approximately constant. Figure 9 The portion of the curve below the thermal oxidation state level 904 can, for example, be considered as the first thermal oxidation region, i.e., region 1, and Figure 9 The portion of the curve above the thermal oxidation state level 904 can be considered, for example, as a second thermal oxidation region, i.e., region 2.

[0120] 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.

[0121] At box 716, 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, i.e., Model 1, can be selected for region 1, and a second thermal oxidation model, i.e., Model 2, can be selected for region 2. Model 1, describing the nonlinear change of the thermal oxidation state Ox over time for region 1, can be represented by Equation 2. Model 2, describing the linear change of the thermal oxidation state Ox over time for region 2, can be represented by Equation 3 below.

[0122] Ox = 1 - [1 - {k(T) × t} eq (1-n)}1 / 1-n (2)

[0123] Ox = k(T) × t eq (3)

[0124] In Equations 2 and 3 above, k(T) is the thermal oxidation rate defined by Equation 1. 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.

[0125] In some examples, a different thermal oxidation model than the thermal oxidation models described in Equations 2 and 3 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 700 may be appropriately modified to use such alternative thermal oxidation models. For example, a different set of inputs than those described in this particular example of method 700 may be applied to the thermal oxidation model, depending on the circumstances.

[0126] It will be understood that once box 702 has been executed, box 716 can be executed at any stage of method 700, because box 716 requires an initial thermal oxidation state.

[0127] At box 718, 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. eg The value of t will be determined from this. eq The values ​​and thermal oxidation parameters are input into the formula selected from Formulas 2 and 3 above, resulting in an updated thermal oxidation state of the brake assembly 200 after a high-temperature event as the output.

[0128] The updated thermal oxidation state can be set as the new initial thermal oxidation state for subsequent use of method 700 in response to subsequent high-temperature events in the temperature profile.

[0129] In some examples, methods 600 and / or 700 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 700 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 704 of method 700, 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 value corresponding to the high-temperature event measured by temperature sensor 216 and those values ​​that lead to an update of the thermal oxidation state of brake assembly 200.

[0130] 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 8 The portion of curve 802 occurring within the time interval represented by 810 can be considered a high-temperature event, and interval 810 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 810, 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 806, 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 810, 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 810 can be the time between subsequent temperature measurements obtained by temperature sensor 216.

[0131] Methods 600 and 700 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.

[0132] On the other hand, in some examples, method 600 or method 700 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.

[0133] For example, the predicted temperature profile can be input into method 600 or method 700, 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 600 or method 700 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.

[0134] 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.

[0135] 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 stage and the previous landing stage.

[0136] 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%).

[0137] 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.

[0138] 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 a thermal oxidation threshold is strictly reached or exceeded during the last future cycle of the first plurality of future cycles, the number of cycles prior to 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 a thermal oxidation threshold is expected to be reached in the next cycle following the first plurality, the first plurality is considered to be the number of cycles prior to requiring repair and replacement due to thermal oxidation.

[0139] Figure 10This is a flowchart of method 1000, which determines the amount of brake wear caused by a braking event using a brake wear model based on the amount of energy absorbed by the brake assembly 200 due to a braking event and the density parameter of the brake assembly 200. The amount of brake wear can be determined for all braking events in which energy is input to the brake assembly 200 during frictional processes that will cause 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 frictional action.

[0140] For example, brake wear can be determined for braking events that do not involve any high-temperature events. For method 1000, 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 aircraft 100 can detect when the brake assembly 200 is applied and when it is released.

[0141] At block 1002 of method 1000, 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.

[0142] 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.

[0143] At block 1004 of method 1000, 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.

[0144] 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 prior to the braking event.

[0145] 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.

[0146] At block 1006 of method 1000, the amount of brake wear caused by a braking event is determined based on a brake wear model using the energy absorbed by the brake assembly 200 and the density parameter from block 1004. 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 4 below.

[0147]

[0148] In formula 4 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.

[0149] As mentioned 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 1006 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.

[0150] 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.

[0151] For example, method 1000 can be executed in real time during a braking event, or for a usage cycle that has already occurred, using relevant data from that usage cycle. Method 1000 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 1000 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 of 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.

[0152] To predict future brake wear, method 1000 can be used in conjunction with method 600 or 700. 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.

[0153] 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).

[0154] On the other hand, in some examples, the prediction of future brake wear can cease at the end of a predicted future service life during which the total brake wear is close to the brake wear threshold, making it possible to expect the total brake wear to reach the brake wear threshold during the next predicted future service life. In this example, it can be assumed that the brake wear threshold will be reached within a second or more predicted future service life. This is because, in practice, the aircraft 100 with brake assembly 200 that is expected to reach the brake wear threshold in a strict sense in the next cycle will not be permitted to fly, and maintenance or replacement related to brake assembly 200 can be performed at this time.

[0155] By using a second plurality of predicted future service cycles, an indication can be given of how many service 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 service 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 service 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 service cycles, the second plurality of predicted future service cycles are considered as the number of cycles before repair or replacement is required.

[0156] Figure 11This is a flowchart of a method 1100 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 1100 can be performed for several predicted future service cycles until a first threshold is reached. Method 1100 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.

[0157] 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. Which threshold is reached first may depend, for example, on how aircraft 100 is handled during use and its flight schedule. For example, 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.

[0158] At block 1102 of method 1100, 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 1104 of method 1100, the future brake wear amount after the same predicted future service life is predicted. The prediction is performed in the context of method 1000 as described above.

[0159] At block 1106 of method 1100, 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 1100 proceeds to block 1108, where the number of good future service cycles prior to reaching either the thermal oxidation threshold or the brake wear threshold is determined, and method 1100 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 1100 has been performed so far.

[0160] On the other hand, if it is determined that the brake wear threshold has been reached, the method proceeds to block 1108, where the number of good future use cycles is determined, and method 1100 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 1100 has been performed so far.

[0161] For example, if both thresholds are reached, method 1100 proceeds to box 1108, where the number of remaining good future use cycles before reaching either the thermal oxidation threshold or the brake wear threshold is determined, and method 1100 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 1100 has been executed so far.

[0162] If the brake wear threshold is not reached, method 1100 proceeds to box 1110, and boxes 1102 to 1110 are repeated for the next predicted future use cycle.

[0163] In this way, the number of good future service cycles can be predicted based on which of the thermal oxidation threshold and 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 1100 can be performed in any suitable order. For example, block 1104 may be performed before block 1102, and / or block 1110 may be performed before block 1106.

[0164] One or more of the methods described above, namely methods 600, 700, 1000, 1100, 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 the 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 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 the examples in 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.

[0165] In the foregoing example, device 300 is described as being installed on a vehicle, such as aircraft 100. Device 300 may be included in the computing system 106 of aircraft 100. For example, a first controller 302 may be implemented by a processor of computing system 106. The processor may implement instructions stored on a computer-readable storage medium of computing system 106 to implement the functions of the first controller 302. Braking system 214 may be implemented by computing system 106 in a similar manner. Alternatively, device 300 and / or braking system 214 may be implemented by a separate device item from computing system 106. For example, a dedicated processor may exist to implement the functions of the first controller 302 and / or the second controller 304 provided on aircraft 100. In some examples, the foregoing functions and processing of device 300 may be performed by braking system 214. In some examples, the first controller 302 and the second controller 304 may be implemented by the same processor or the same group of processors. In some examples, the first controller 302 and the second controller 304 may be implemented by different processors or different groups of processors.

[0166] All or part of the instructions for performing the above processing can be generated, and / or any suitable software or combination of software can be used to perform the processing. In one example, "MATLAB" and / or "SCADE" can be used to generate all or part of the instructions for performing any of the above processing on the corresponding processor. 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.

[0167] It should be noted that, unless otherwise expressly stated, the term "or" as used herein should be interpreted as "and / or". Although the invention has been described herein 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 controlling a vehicle, comprising: a first controller configured to: generate a first indication for a braking system of the vehicle in dependence on a thermal oxidation state of a wheel brake of the vehicle, wherein the first controller is configured to: determine a brake temperature characteristic criterion for the brake in dependence on the thermal oxidation state of the brake; determine whether a temperature characteristic of the brake meets the brake temperature characteristic criterion; and generate the first indication for the braking system in dependence on whether the brake temperature characteristic meets the brake temperature characteristic criterion, wherein the temperature characteristic of the brake comprises a temperature of the brake; and wherein the brake temperature characteristic criterion is met if the temperature of the brake exceeds a brake temperature threshold, and wherein the first controller is configured such that the higher the thermal oxidation level of the brake, the lower the brake temperature threshold of the determined brake temperature characteristic criterion.

2. The apparatus of claim 1, wherein, the first controller receives an indication of the temperature characteristic of the brake from a temperature sensor associated with the brake.

3. The apparatus of claim 1, wherein, the first controller receives a predicted temperature characteristic as the temperature characteristic of the brake from a brake temperature prediction function.

4. The apparatus of claim 2 or 3, wherein, the first controller is configured to: monitor the temperature characteristic of the brake; and generate a second indication for the braking system in which the temperature characteristic of the brake no longer meets the brake temperature characteristic criterion if the temperature characteristic of the brake no longer meets the brake temperature characteristic criterion.

5. The apparatus of claim 1, wherein, a first brake temperature characteristic criterion comprising a first temperature threshold is selected if the thermal oxidation state of the brake is below a predetermined thermal oxidation level.

6. The apparatus of claim 5, wherein, a second brake temperature characteristic criterion comprising a second temperature threshold is selected if the thermal oxidation state of the brake is above the predetermined thermal oxidation level, the second temperature threshold being lower than the first temperature threshold.

7. The apparatus of claim 6, wherein, the second brake temperature characteristic criterion is selected based on a difference between the thermal oxidation state of the brake and the predetermined thermal oxidation level.

8. The apparatus of any one of claims 5-7, wherein, the first temperature threshold is above 400°C.

9. A vehicle comprising the apparatus of any one of claims 1 to 8 and a braking system comprising a second controller, wherein, the second controller is configured to: receive the first indication; and control operation of the brake based on the first indication.

10. The vehicle of claim 9, wherein: the second controller is configured to: receive a second indication that the temperature characteristic of the brake no longer meets the brake temperature characteristic criterion; and selectively control the brake to be enabled or disabled based on the received indication.

11. The vehicle of claim 10, wherein, the second controller is configured to control the brake to be disabled if the first indication is received.

12. The vehicle of claim 11, wherein, the second controller is configured to control the brake to be enabled if the second indication is received.

13. The vehicle of claim 11, wherein, The vehicle is an aircraft, and the second controller is configured to disable the brakes if a taxiing criterion is met, wherein the taxiing criterion comprises one or more of: an aircraft speed threshold defined such that an aircraft speed less than or equal to the aircraft speed threshold meets a predefined taxiing criterion; and a particular flight phase indicated by a flight phase indication system of the aircraft.

14. The vehicle of claim 11, wherein, The second controller is configured to: receive a brake request, the brake request comprising information relating to a requested brake intensity; determine, based on the information relating to the requested brake intensity, whether the requested brake intensity exceeds a brake intensity threshold; and if the requested brake intensity exceeds the brake intensity threshold, enable at least one disabled brake.

15. The vehicle of any one of claims 9 to 14, wherein the vehicle is an aircraft comprising a temperature sensor configured to measure a temperature of a wheel brake of the aircraft and send a temperature measurement to the device.

16. A method for controlling at least one wheel brake of an aircraft, the method comprising: generating a first indication from a thermal oxidation state of a wheel brake of an aircraft; and controlling the brake to be disabled based on the first indication, wherein the method further comprises: determining a brake temperature characteristic criterion for the brake from the thermal oxidation state of the brake; determining whether a temperature characteristic of the brake meets the brake temperature characteristic criterion; and generating the first indication from whether the brake temperature characteristic meets the brake temperature characteristic criterion, wherein the temperature characteristic of the brake comprises a temperature of the brake, and wherein the brake temperature characteristic criterion is met if the temperature of the brake exceeds a brake temperature threshold, and wherein the higher the thermal oxidation level of the brake, the lower the brake temperature threshold of the determined brake temperature characteristic criterion.

17. The method of claim 16, comprising: (i) monitoring the temperature characteristic of the brake; (ii) determining whether the temperature characteristic of the brake still meets the brake temperature characteristic criterion; if the temperature characteristic of the brake no longer meets the brake temperature characteristic criterion: generating a second indication that the temperature characteristic of the brake no longer meets the brake temperature characteristic criterion; and controlling the brake to be enabled based on the second indication; and if the temperature characteristic of the brake still meets the brake temperature characteristic criterion, repeating (i) and (ii).

18. The method of claim 16, comprising receiving an indication of the temperature characteristic of the brake from a temperature sensor associated with the brake.

19. The method of claim 16, comprising receiving a predicted temperature characteristic as the temperature characteristic of the brake from a brake temperature prediction function.

20. The method of claim 16, wherein, if the thermal oxidation state of the brake is below a predetermined thermal oxidation level, selecting a first brake temperature characteristic criterion comprising a first temperature threshold.

21. The method of claim 20, wherein, if the thermal oxidation state of the brake is higher than the predetermined thermal oxidation level, a second brake temperature characteristic criterion comprising a second temperature threshold is selected, the second temperature threshold being lower than the first temperature threshold.

22. The method of claim 21, wherein, the second brake temperature characteristic criterion is selected based on a difference between the thermal oxidation state of the brake and the predetermined thermal oxidation level.

23. The method of claim 20, wherein, the first temperature threshold is higher than 400°C.

24. The method of any one of claims 16 to 23, wherein, disabling the wheel brakes in case a predefined coasting criterion is fulfilled, wherein the predefined coasting criterion comprises one or more of: an aircraft speed threshold defined such that an aircraft speed smaller or equal to the aircraft speed threshold fulfils the predefined coasting criterion; and a certain flight phase indicated by a flight phase indication system of the aircraft.

25. The method of claim 24, wherein, The method comprises: receiving a brake request, the brake request comprising information related to a requested brake intensity; determining, based on the information related to the requested brake intensity, whether the requested brake intensity exceeds a brake intensity threshold; and if the requested brake intensity exceeds the brake intensity threshold, enabling at least one disabled brake.

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