Fault tolerant braking load alleviation

Abstract

The present disclosure relates to fault-tolerant brake load mitigation. A brake system control unit includes one or more sensor interfaces configured to receive a brake torque signal from a brake torque sensor. The brake system control unit also includes a torque estimator configured to generate an estimated brake torque signal based at least in part on a brake model and a brake actuator command. The brake system control unit also includes a control circuit configured to generate the brake actuator command to actuate a brake actuator of a brake system. The brake actuator command is generated based on a brake pedal command and a load mitigation command. The load mitigation command is generated based on the brake torque or the estimated brake torque signal depending on whether a sensor fault condition associated with the brake torque sensor is detected.

Description

Technical Field

[0001] This disclosure generally relates to braking load mitigation systems and methods. In particular, this disclosure relates to fault-tolerant braking load mitigation systems and methods. Background Technology

[0002] All else being equal, lighter vehicles tend to be more efficient than heavier ones. Therefore, vehicle designers, manufacturers, and users may be more inclined to reduce the structural weight of a vehicle; however, the options for reducing the structural weight of many vehicles are limited by material and design considerations. For example, a vehicle undergoing sudden braking may experience significant loads. The anticipated load amplitude due to strong braking can be large enough to drive the design of the vehicle structure, potentially leading to an increase in vehicle weight. Summary of the Invention

[0003] In one particular implementation, a braking system control unit includes one or more sensor interfaces configured to receive braking torque signals from a braking torque sensor. The braking system control unit also includes a torque estimator configured to generate an estimated braking torque signal based at least in part on a braking model and brake actuator commands. The braking system control unit further includes control circuitry configured to generate brake actuator commands to actuate the brake actuators of the braking system. The brake actuator commands are generated based on brake pedal commands and load relief commands. Depending on whether a sensor malfunction associated with the braking torque sensor is detected, the load relief command is based on either the braking torque signal or an estimated braking torque signal.

[0004] In another specific implementation, a method includes receiving a brake pedal command at a brake system control unit. The method further includes determining, at the brake system control unit, whether a sensor fault condition is detected based on a brake torque signal from a brake torque sensor. The method also includes, in response to detecting a sensor fault condition, accessing a brake model from memory accessible to the brake system control unit; generating an estimated brake torque signal based on the brake model and a brake actuator command; and generating a load relief command based on the estimated brake torque signal.

[0005] In another specific implementation, a vehicle includes: one or more wheels coupled to a structure; and one or more braking systems. Each braking system includes one or more sensors and one or more brake actuators. The vehicle also includes one or more braking system control units. Each braking system control unit includes one or more sensor interfaces configured to receive braking torque signals from a braking torque sensor. Each braking system control unit includes a torque estimator configured to generate an estimated braking torque signal based at least in part on a braking model and brake actuator commands. Each braking system control unit also includes control circuitry configured to generate brake actuator commands to actuate one or more of the brake actuators. The brake actuator commands are generated based on brake pedal commands and load relief commands. Depending on whether a sensor malfunction condition associated with the braking torque sensor is detected, the load relief command is based on either the braking torque signal or the estimated braking torque signal.

[0006] The features, functions, and advantages described herein can be implemented independently or in combination in various embodiments, further details of which can be found in the following description and figures. Attached Figure Description

[0007] Figure 1 It is a block diagram of a braking system based on a specific implementation, which is configured to provide fault-tolerant braking load reduction.

[0008] Figure 2 It depends on the specific implementation, including Figure 1 A block diagram of a vehicle with a braking system, which is connected to one or more structures.

[0009] Figure 3 This illustrates implementation-specific examples. Figure 1 A diagram of the braking system.

[0010] Figure 4 This illustrates implementation-specific examples. Figure 1 A diagram of the braking system.

[0011] Figure 5 It is based on Figure 1 An example of a table containing historical braking commands and braking torque data for a specific implementation of the braking system.

[0012] Figure 6 It is based on Figure 1 Another example of a specific implementation of a braking system includes a table containing historical braking commands and braking torque data.

[0013] Figure 7 It is based on Figure 1 An example of a data structure for a specific implementation of a braking system, including historical braking commands and braking torque data.

[0014] Figure 8 This is an example based on Figure 1 A graph showing aspects of a specific implementation of the braking system's braking model.

[0015] Figure 9 It is based on a specific implementation. Figure 1 The flowchart shows the method for implementing the braking system.

[0016] Figure 10 It is based on a specific implementation. Figure 1 A flowchart of another method for implementing the braking system.

[0017] Figure 11 Examples include Figure 1 A flowchart of the vehicle's lifecycle for the braking system control unit.

[0018] Figure 12 Examples include Figure 1 A diagram showing a specific example of a vehicle's braking system control unit. Detailed Implementation

[0019] The weight of structural components connected to the braking system of some vehicles can be reduced by using a brake load mitigation system. Brake load mitigation systems protect vehicle structural components by limiting the loads applied to them during braking. For example, a closed-loop brake load mitigation system uses sensor feedback data to indicate the braking force or torque applied during braking and limits that force or torque to a specific threshold to protect the vehicle's structural components.

[0020] In such systems, sensors that provide feedback data are typically located at or near the vehicle's wheels. Therefore, these sensors may be exposed to harsh environments, leading to sensor failure. When sensor feedback data becomes unavailable due to sensor failure, the brake load mitigation system will be bypassed or operated in open-loop mode.

[0021] When the brake load mitigation system is bypassed or in open-loop mode, load limits enforced by the brake load mitigation system may be exceeded unless other operational restrictions are imposed on the vehicle. For example, the aircraft may need to operate at reduced takeoff weight limits to ensure that structural load limits are not exceeded. As another example, the vehicle's braking distance may be increased to reduce peak braking force. In the aircraft example, the increased braking distance may require the aircraft to use a longer runway, which, if unavailable or overloaded, could delay the aircraft's dispatch.

[0022] This document discloses systems and methods for fault-tolerant braking load mitigation. The disclosed systems and methods can improve the operation of braking load mitigation systems in the presence of sensor failures. For example, the disclosed systems and methods can enable braking load mitigation systems to operate even if sensor failures would prevent conventional braking load mitigation systems from performing their intended functions. The disclosed fault-tolerant braking load mitigation systems and methods use a vehicle-specific (or even axle-specific or wheel-specific) braking model generated during closed-loop operation to generate estimated feedback sensor signals when feedback signals are unavailable or unreliable (e.g., due to sensor failure). Because the braking model is tailored to a specific vehicle (and possibly a specific axle or wheel of the vehicle) and is frequently updated, the estimated feedback signals reliably limit the loads borne by the vehicle structure, enabling the vehicle to operate without imposing additional operational constraints (e.g., operating weight limits or braking distance limits).

[0023] The accompanying drawings and the following description illustrate specific exemplary embodiments. It will be understood that, although not explicitly described or shown herein, those skilled in the art will be able to devise various arrangements that implement the principles described herein and are included within the scope of the claims appended to this specification. Furthermore, any examples described herein are intended to aid in understanding the principles of this disclosure and should be construed as not limiting. Therefore, this disclosure is not limited to the specific embodiments or examples described below, but is limited by the claims and their equivalents.

[0024] This document describes a particular implementation with reference to the accompanying drawings. Throughout the description, the same features are indicated by the same reference numerals. Some features described herein are singular in some implementations and plural in others. For illustrative purposes, Figure 2 It describes a system including one or more braking systems 100. Figure 2 The vehicle 200 (of which the term "braking system" is used) indicates that in some implementations the vehicle 200 includes a single braking system 100, while in other implementations the vehicle 200 includes multiple braking systems 100. For ease of reference herein, such features are generally introduced as "one or more" features and are subsequently referred to as the optional plural. Such features may also be referred to in the singular form when describing representatives of such features.

[0025] The various terms used herein are for the purpose of describing a particular implementation only and are not intended to be restrictive. For example, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” are also intended to include the plural forms. The term “comprising” is used interchangeably with “including.” Furthermore, the terms “in which” and “wherein” are used interchangeably. As used herein, “exemplary” means example, implementation, and / or aspect and should not be construed as limiting or indicating a preference or preferred implementation. As used herein, ordinal terms used to modify elements such as structures, components, operations, etc. (e.g., “first,” “second,” “third,” etc.) do not themselves indicate any priority or order of an element relative to another element, but merely distinguish that element from another element with the same name (but used in ordinal terms). As used herein, the term “set” refers to a grouping of one or more elements, while the term “multiple” refers to multiple elements.

[0026] As used herein, the terms “generate,” “calculate,” “use,” “select,” “access,” and “determine” are interchangeable unless the context otherwise requires. For example, “generate,” “calculate,” or “determine” a parameter (or signal) can refer to actively generating, calculating, or determining a parameter (or signal), or it can refer to using, selecting, or accessing a parameter (or signal) that has already been generated, for example, by another component or device. As used herein, “connection” can include “communication connection,” “electrical connection,” or “physical connection,” and may also (or alternatively) include any combination thereof. Two devices (or components) can be directly or indirectly connected (e.g., communication connection, electrical connection, or physical connection) via one or more other devices, components, wires, buses, networks (e.g., wired networks, wireless networks, or combinations thereof). As an illustrative, non-limiting example, two electrically connected devices (or components) can be in the same or different devices and can be connected via electronics, one or more connectors, or inductive connections. In some implementations, two devices (or components) in a communication connection (e.g., electrical communication) can send and receive electrical signals (digital or analog signals) directly or indirectly (e.g., via one or more wires, buses, networks). As used herein, "direct connection" is used to describe the connection of two devices without an intermediary (e.g., a communication connection, an electrical connection, or a physical connection).

[0027] The following discussion frequently uses braking torque as an indication of the load applied to the vehicle structure. First, it should be noted that braking force or load can be used instead of braking torque, or in addition to braking torque, braking force or load can be used to indicate the load applied to the vehicle structure. For ease of description (e.g., instead of consistently referring to "braking torque or braking force"), braking torque will be used throughout the following description. However, it is understood that braking force can be used instead of braking torque throughout the following description, and the corresponding calculations can be modified as needed (e.g., by converting force to torque using data describing the braking system configuration and structural attachments).

[0028] Figure 1 An example of a braking system 100 according to a particular implementation is depicted. Braking system 100 includes a brake load mitigation system 134 configured to limit the load applied to the vehicle structure during vehicle braking. The target brake load of brake load mitigation system 134 can vary as a function of time to further limit dynamic brake loads. As a result, the structure can be designed to withstand smaller brake loads than might be encountered without brake load mitigation system 134. Brake load mitigation system 134 uses feedback (e.g., brake torque signal 128) from one or more brake torque sensors 126 to limit brake loads. For example, brake torque signal 128 indicates the load applied to the vehicle structure during braking operation, and during normal operation (e.g., when no sensor failure is detected), brake load mitigation system 134 determines a load mitigation command 136 based on brake torque signal 128. Load mitigation command 136 is used to limit brake actuator commands 118 sent to brake actuation system 120 in response to brake pedal command 106.

[0029] The braking system 100 also includes a fault-tolerant torque system 130. The fault-tolerant torque system 130 is configured to detect whether the braking torque sensor 126 is experiencing a fault condition. If the fault-tolerant torque system 130 detects a fault condition associated with the braking torque sensor 126, it provides an estimated braking torque signal 132 (instead of the braking torque signal 128) to the braking load mitigation system 134. The estimated braking torque signal 132 is generated based on a model of the braking system 100. In a specific aspect, during braking operations where the fault-tolerant torque system 130 does not detect a fault condition, the fault-tolerant torque system 130 updates the model of the braking system 100. Therefore, the model is updated periodically, and the fault-tolerant torque system 130 is able to generate a value for the estimated braking torque signal 132 that is very close to the value of the braking torque signal 128 that would exist in the absence of a sensor fault condition.

[0030] Braking system 100 includes pedal system 104, which is configured to generate brake pedal command 106 based on input from user 102. Brake pedal command 106 is combined with load relief command 136 at a first node 108 to generate brake pedal command 110 compensated for brake load relief. Load relief command 136 limits brake pedal command 106 to prevent braking operation from exceeding specified load limits associated with the structure.

[0031] In some implementations, braking system 100 includes or is coupled to braking automation system 112, which provides a braking command (e.g., braking automation system command 114) that is combined at a second node 116 with a brake pedal command 110 that has been compensated for brake load reduction to generate a brake actuator command 118. In implementations that do not include braking automation system 112, the brake pedal command 110 that has been compensated for brake load reduction is used as the brake actuator command 118.

[0032] A brake actuator command 118 is provided to the brake actuation system 120, which actuates the brake 124 in response to the command. The brake 124 performs a braking operation that reduces the vehicle's speed and applies the resulting load to the vehicle structure. If the brake torque sensor 126 is operating normally, it sends a brake torque signal 128 to the fault-tolerant torque system 130. The brake torque signal 128 indicates the measured braking torque generated due to the braking operation. If the brake torque sensor 126 is experiencing a fault condition, it either does not generate a brake torque signal 128 or generates a brake torque signal 128 outside the expected range.

[0033] The fault-tolerant torque system 130 evaluates the braking torque signal 128 to determine whether the braking torque sensor 126 is experiencing a fault condition. If no fault condition is detected, the fault-tolerant torque system 130 outputs the braking torque signal 128 to the braking load relief system 134. If a fault condition is detected, the fault-tolerant torque system 130 outputs an estimated braking torque signal 132. The estimated braking torque signal 132 is generated based on a model of the braking system 100 and brake actuator commands 118, as further described below.

[0034] The brake load relief system 134 generates a load relief command 136 based on the brake torque signal 128 or the estimated brake torque signal 132. Therefore, the brake load relief system 134 can operate reliably when a sensor malfunction is detected.

[0035] Figure 2An example of a vehicle 200 is depicted, which includes one or more wheels 204 coupled to one or more structures 202. The vehicle 200 also includes one or more braking systems 100. The braking systems 100 are configured to limit the load applied to the structures 202 during braking. As a result, the structures 202 can be designed to withstand smaller braking loads than might be encountered without the described braking systems 100. Ensuring that the structures 202 withstand smaller braking loads allows vehicle designers to reduce the overall weight of the vehicle 200. The vehicle 200 can include or correspond to any wheeled vehicle with onboard brakes. For example, the vehicle 200 can be a land vehicle, such as a truck, train, or car. As another example, the vehicle 200 can be an aircraft, in which case the wheels 204 correspond to wheels mounted on the landing gear. Furthermore, the vehicle 200 can be moved by an onboard engine or motor, or the vehicle 200 can be moved by an external source. For example, the vehicle 200 can include a trailer or railcar with an onboard braking system.

[0036] In a particular implementation, each wheel 204 is associated with a braking system 100. In some implementations, a braking system 100 is associated with two or more of the wheels 204 (e.g., multiple wheels on the same axle). Figure 2 In the illustrated example, each braking system 100 includes a brake actuation system 120, such as a pneumatic, electrical, or hydraulic power source that provides power to actuate one or more brake actuators 236 of the braking system 100. In other implementations, two or more braking systems 100 share a brake actuation system 120. For example, a single hydraulic system may be coupled to two or more braking systems 100 of the vehicle 200.

[0037] Many implementations use friction-based braking. In such implementations, each brake actuator 236 is indirectly coupled to one of the wheels 204 via a pair of friction surfaces. For example, the wheel 204 is coupled to a rotor or drum that includes a first friction surface that rotates with the wheel 204. In this example, the brake actuator 236 associated with the wheel 204 is coupled to a brake stator, brake pad, or brake shoe that includes a second friction surface. The brake actuator 236 moves the second friction surface to contact or away from the first friction surface. For illustration, during braking, the brake actuator 236 compresses the second friction surface to contact the first friction surface to reduce the rotational rate of the wheel 204. In other implementations, the braking system 100 uses a mechanism other than friction or replacing friction to reduce the rotational rate of the wheel 204. One example of a frictionless braking mechanism is regenerative braking, where an electromotive force is used to reduce the rotational rate of the wheel 204. Other examples include compression braking or hydraulic braking, where braking causes fluid compression or creates fluid resistance to reduce the rotational rate of the wheel 204.

[0038] exist Figure 2 In the illustrated example, braking system 100 includes or is associated with braking automation system 112 (e.g., automatic braking system 212 and / or anti-skid system 214). Braking system 100 also includes one or more braking system control units 220. Each braking system control unit 220 includes control circuitry 222, one or more sensor interfaces 224, and a brake load mitigation system 134. In some implementations, braking automation system 112 is integrated within braking system control unit 220. In yet other embodiments, braking automation system 112 is omitted.

[0039] The sensor interface 224 of the braking system control unit 220 is configured to receive sensor data and / or signals from the sensors 230 of the braking system 100. For example, the sensors 230 may include one or more braking torque sensors 126 configured to provide one or more braking torque signals to the braking system control unit 220 via the sensor interface 224. In some implementations, one or more braking load sensors may be used in place of the braking torque sensors 126 or in addition to the braking torque sensors 126. As another example, the sensors 230 may include one or more braking operating environment sensors 234 configured to provide one or more braking operating environment signals to the braking system control unit 220 via the sensor interface 224. The braking operating environment sensors 234 measure conditions such as vehicle speed, ground speed, wheel speed, brake temperature, wheel temperature, or other braking-related conditions.

[0040] Control circuit 222 is configured to respond to one or more braking input signals (e.g., Figure 1 Brake pedal command 106 Figure 1 The braking automation system command 114 (or both) generates a brake actuator command to actuate the brake actuator 236. The brake load relief system 134 is configured to provide... Figure 1 The load relief command 136 limits the braking actuation signal so that the load applied to a portion of the structure 202 during braking is less than the specified load limit 254.

[0041] For example, during operation, the braking system 100 receives a braking input signal (e.g., Figure 1 Brake pedal command 106 Figure 1 (Brake automation system command 114, or both). Brake system control unit 220 provides braking actuation system 120 based on brake input signal and load relief command 136 from brake load relief system 134. Figure 1 The brake actuator command 118. During normal operation, the load relief command 136 is based on the brake torque signal 128 from the brake torque sensor 126. However, when the sensor monitor 240 of the fault-tolerant torque system 130 detects a sensor failure condition associated with the brake torque sensor 126, the load relief command 136 from the brake load relief system 134 is determined based on one or more brake models 256 of the fault-tolerant torque system 130.

[0042] Sensor monitor 240 is configured to detect fault conditions associated with sensor 230. For example, sensor monitor 240 can detect the measured braking torque value (from...) Figure 1 The braking torque signal 128 (represented by the sensor) is compared with one or more fault criteria 242. In this example, fault criteria 242 indicate the expected range of braking torque values, and if the measured braking torque value is outside the expected range, the sensor monitor 240 indicates that a sensor fault condition has been detected. In some implementations, the expected range of braking torque values ​​is based on braking torque values ​​stored in memory during periods of operation of the braking system 100 when no fault condition is detected. Additionally or alternatively, in some implementations, the expected range of braking torque values ​​is based on default values, such as braking torque values ​​determined during testing of vehicle 200 or other similar vehicles.

[0043] In some implementations, at least one of the failure criteria 242 is based on historical braking torque values ​​and one or more brake actuator command values ​​associated with one or more historical braking torque values. The brake actuator command values ​​correspond to those specified by... Figure 1 The value indicated by brake actuator command 118. For example, brake actuator command 118 may indicate the relative magnitude of braking operation, such as a percentage of the operating range of braking system 100. For example, a 50% brake actuator command value indicates that the braking operation should be approximately half of the braking operation actively performed in response to a 100% brake actuator command value. Figure 5 Table 500 illustrates an example of a threshold 508 associated with fault criterion 242 according to an instruction of a specific implementation. Figure 5 Table 500 includes a set 504 of initial default braking torque values ​​and a set 506 of subsequent historical braking torque values, where each braking torque value corresponds to a specific value of the brake actuator command. In some implementations, Table 500 presents values ​​for specific braking operating environmental conditions, such as specific brake temperature, wheel temperature, wheel speed, ground speed, or combinations thereof that can affect braking torque. In such implementations, other tables may be used to present values ​​for other braking operating environmental conditions.

[0044] exist Figure 5 In this context, threshold 508 indicates the lower limit of valid brake torque sensor readings for each brake actuator command value. For example, for ten percent (10%) of brake actuator command values ​​502, based on threshold 508, a brake torque sensor reading of 0 feet-pounds (ft-lbs) or greater is considered valid; however, for fifty percent (50%) of brake actuator command values ​​502, a brake torque sensor reading of 24,200 ft-lbs or greater is considered valid. In some implementations, table 500 may also indicate upper thresholds for one or more brake actuator command values ​​502.

[0045] In some implementations, threshold 508 is determined based on historical braking torque values ​​506. For example, threshold 508 for 50% (50%) of brake actuator command values ​​can be determined based on statistical analysis of historical braking torque values ​​506 corresponding to 50% (50%) of brake actuator command values. For illustration, threshold 508 for 50% (50%) of brake actuator command values ​​can be set based on a multiple (e.g., 2x) of the standard deviation of historical braking torque values ​​506 corresponding to 50% (50%) of brake actuator command values. In other exemplary examples, other statistical analyses can be used to determine a lower (or upper) bound for effective sensor readings based on historical braking torque values ​​506.

[0046] Back Figure 2 For example, the fault-tolerant torque system 130 includes a torque estimator 250, which is configured to generate a torque estimator when the sensor monitor 240 detects a sensor failure condition. Figure 1 The estimated braking torque signal 132 is based at least in part on one or more braking models 256 and brake actuator commands 118 provided to the braking actuation system 120. The braking model 256 correlates the brake actuator commands 118 (and possibly other data, such as braking operating environment data) with historical braking torque values ​​measured during operating periods when no sensor malfunction was detected. As an example, the braking model 256 may include parameters of a gain-based torque estimation function (e.g., Equation 1):

[0047] τ estimate =B x G Formula 1

[0048] Where τ estimate B is the estimated braking torque value, B is the value indicating the braking operation amplitude (e.g., the value of the brake actuator command), and G is the braking gain value based on historical braking torque measurements during periods when no sensor malfunction was detected. In some implementations, the braking gain value G has different values ​​depending on braking operating environment values ​​(e.g., wheel speed, ground speed, brake temperature, or wheel temperature).

[0049] Additionally or alternatively, the value of the braking gain G may be valid for a specific range of brake actuator command values. For example, the matrix data structure may include braking gain values ​​G for various combinations of brake actuator command values, wheel speeds, ground speeds, brake temperatures, wheel temperatures, or other braking-related values. In some cases, it is used to calculate the estimated braking torque value τ. estimate The braking gain value G can be determined by interpolation between the available brake actuator command value and the braking gain value. In this example, the estimated braking torque value τ estimate The braking gain value G is determined by selecting the braking gain value G based on the brake actuator command value B, the value of the braking operation environment signal, or both, and then multiplying the selected braking gain value G by the brake actuator command value B.

[0050] As another example, braking model 256 may include one or more tables or other data structures or knowledge representations that store measured braking torque values ​​when a specific brake actuator command 118 is provided to brake actuation system 120 during historical braking operations in which no sensor fault was detected. In this example, if a sensor fault is detected during braking, the value of brake actuator command 118 sent to brake actuation system 120 is used to look up, retrieve, and / or calculate an estimated braking torque value from braking model 256. If the value of brake actuator command 118 does not precisely correspond to a brake actuator command value in braking model 256, the estimated braking torque value can be estimated by interpolation between two or more values ​​in braking model 256. Alternatively, braking model 256 may include both a braking gain value G from Equation 1 and values ​​from one or more tables. In this example, a coarse estimate of the braking torque value can be determined from one or more tables and subsequently refined using a braking gain function.

[0051] Figure 6 Table 600 illustrates an example of estimated braking torque values ​​602 for various brake actuator command values ​​502, based on instructions from a specific implementation. Figure 6 Table 600 includes references. Figure 5 The description includes the set of initial default braking torque values ​​504 and the set of historical braking torque values ​​506. Figure 6In the illustrated example, the estimated braking torque value 602 associated with each brake actuator command value 502 is the average of the historical braking torque values ​​506 for the brake actuator command value 502. For example, for thirty percent (30%) of the brake actuator command values ​​502, the estimated braking torque value 602 is 30756, which is the average value determined based on the historical braking torque values ​​506. In some implementations, a moving average is used. For example, after a certain number of historical braking torque values ​​506 are stored in table 600, a new historical braking torque value 506 added to table 600 replaces the oldest historical braking torque value 506 for the same brake actuator command value 502, and the average of the historical braking torque values ​​506 is recalculated to determine the estimated braking torque value 602 for the brake actuator command value 502. If enough historical braking torque values ​​506 are unavailable, an initial default braking torque value 504 is used to determine the estimated braking torque value 602.

[0052] In some implementations, the brake load mitigation system 134 includes different brake models 256 for different braking operating environments. In such implementations, a specific brake model 256 is selected for use in a particular situation based on braking operating environment values ​​from a braking operating environment sensor 234. For example, Figure 7 An example of a set 700 of tables for a specific implementation of braking model 256 is shown. Figure 7 In this example, table 600 is a first table associated with a first braking operating environment value (e.g., a first braking temperature value T1). In this example, the set of tables 700 also includes one or more additional tables associated with other braking operating environment values, such as a second table 704 associated with a second braking temperature value T2 and a third table 706 associated with a third braking temperature value T3. In this example, the estimated braking torque value can be interpolated between tables 600, 704, and 706, between brake actuator command values ​​502, or between both. For illustration, the estimated braking torque value for a brake actuator command value 502 at a braking temperature value between T2 and T1 at 45% of its rated value can be determined by interpolation between two estimated braking torque values: the estimated braking torque value associated with brake actuator command values ​​502 at 40% and 50% of their rated values ​​for braking temperature T1, and the estimated braking torque value associated with brake actuator command values ​​502 at 40% and 50% of their rated values ​​for braking temperature T2. Although in Figure 7 The braking temperature is used as an example, but in other examples, other braking operating environment values ​​besides braking temperature or in lieu of braking temperature are used.

[0053] Figure 8An example of a braking model 256, represented as a surface 812 in feature space 802 according to another specific implementation, is illustrated. Figure 8 In the feature space 802, there is a brake actuator command dimension 806, a brake torque dimension 808, and one or more brake operation environment dimensions 804. For ease of illustration, Figure 8 Only one braking operating environment dimension 804 is shown. However, in some implementations, the feature space 802 includes more than one braking operating environment dimension 804. For example, the feature space 802 may include a wheel temperature dimension and a wheel speed dimension, or some other combination of braking operating environment dimensions.

[0054] exist Figure 8 In the illustrated example, the coordinate position of a specific point on surface 812 in feature space 802 indicates the desired braking torque value for a given braking operating environment value and brake actuator command value. For illustration, in Figure 8 In the process, it can be based on the coordinates of the braking operation environment (e.g., Figure 8 The coordinates of the brake actuator command value (e.g., E3) and the coordinates of the brake actuator command value (e.g., Figure 8 The approximate percentage (75%) is used to identify point 810 on surface 812. The braking operating environment coordinates and the braking actuator command coordinates together specify a unique location on surface 812, and the estimated braking torque value for the unique location (e.g., point 810) is specified by the braking torque coordinates of point 810.

[0055] exist Figure 2 In this system, the fault-tolerant torque system 130 also includes a model updater 252. The model updater 252 is configured to update the braking model 256 when no sensor failure condition associated with the braking torque sensor 126 is detected. For example, the model updater 252 may store model update data that correlates the value from the brake actuator command 118 with the braking torque value from the braking torque signal 128. As another example, the model updater 252 may validate or update the parameters of the braking gain function (e.g., Equation 1) based on the value of the brake actuator command 118 and the braking torque value. In some implementations, the model update data also correlates the values ​​of braking operating environment data with the brake actuator command value and the braking torque signal.

[0056] Therefore, when a sensor malfunction is detected, the fault-tolerant torque system 130 enables fault-tolerant and reliable operation of the brake load mitigation system 134. For example, on an aircraft, the fault-tolerant torque system 130 determines the force or torque gain of each brake on a given landing gear and stores the information in the memory of the brake system control unit 220 to generate a brake model 256. The brake model 256 (by the model updater 252) is updated periodically or periodically to account for variations in the brake system 100 or other parts of the vehicle 200. During the initial learning phase (e.g., before sufficient operational data is available to generate a brake model 256 tailored for the brake system 100), the brake model 256 uses default values ​​(e.g., based on test or certification data of the vehicle or based on conservative engineering estimates). For example, during the initial learning phase, the fault-tolerant torque system 130 uses initial parameters of the brake model 256 to determine an estimated brake torque signal 132, and subsequently uses updated parameters generated by the model updater 252.

[0057] Although sensor interface 224, control circuit 222, fault-tolerant torque system 130 and braking load reduction system 134 are in Figure 2 While depicted as separate components, in other implementations, the functions described for two or more of the sensor interface 224, control circuitry 222, fault-tolerant torque system 130, and brake load mitigation system 134 may be performed by a single component. In some implementations, each of the sensor interface 224, control circuitry 222, fault-tolerant torque system 130, and brake load mitigation system 134 corresponds to or includes hardware (e.g., an application-specific integrated circuit (ASIC) or a field-programmable gate array (FPGA)), or the operations described with reference to the sensor interface 224, control circuitry 222, fault-tolerant torque system 130, and brake load mitigation system 134 may be performed by a processor executing computer-readable instructions.

[0058] Figure 3 This illustrates implementation-specific examples. Figure 1 and Figure 2 A diagram of the braking system 100. Figure 3 The illustrated figures show a single wheel 204 and associated components (e.g., one or more struts 312, brake actuators 236, actuator sensors 238, brake clamps 314, one or more rotors 316, one or more brake torque sensors 126, and one or more brake operating environment sensors 234). When more than one wheel 204 of the vehicle 200 has brakes, the control circuitry 222, brake load mitigation system 134, fault-tolerant torque system 130, and components associated with each braked wheel 204 can be replicated.

[0059] exist Figure 3 In this configuration, brake pedal 332 is connected to brake pedal sensor 302. Brake pedal sensor 302 generates brake pedal input signal 304 based on the position of brake pedal 332. Brake pedal command logic 306 generates brake pedal command 106, which is provided to control circuit 222 and fault-tolerant torque system 130. Figure 3 In the illustrated implementation, the fault-tolerant torque system 130 uses brake pedal command 106 to determine the braking mode, which helps detect sensor malfunctions, as shown in the reference. Figure 4 As described.

[0060] The first node 108 of the control circuit 222 determines the brake pedal command 110 after brake load reduction compensation based on the difference between the brake pedal command 106 and the load reduction command 136 from the brake load reduction system 134. The load reduction command 136 is based on the brake torque signal 128 from the fault-tolerant torque system 130 or the estimated brake torque signal 132.

[0061] exist Figure 3 In this example, the second node 116 determines the brake actuator command 118 based on the brake pedal command 110 compensated for brake load reduction and one or more brake automation system commands 114 from the brake automation system 112. In this example, the brake automation system 112 includes a system or component that provides brake input via a mechanism other than the brake pedal 332. Figure 2 The automatic braking system 212 and the anti-skid system 214 are examples of this automatic braking system 112. Although Figure 3 The first node 108 and the second node 116 are exemplified as summation nodes. In other implementations, more complex control logic can be used.

[0062] exist Figure 3 In the example, brake actuator command 118 is provided to fault-tolerant torque system 130. Brake actuator command 118 is also provided to Figure 1 and Figure 2 The braking actuation system 120, in Figure 3 In this system, the braking actuation system 120 includes a third node 308, a brake actuator 236, an actuator sensor 238, and a compensator 322. The third node 308 generates a brake actuator signal 310 based on a brake actuator command 118 and an actuator compensation command 324 from the compensator 322. The compensator 322 generates the actuator compensation command 324 based on an actuator sensor signal 320 from the actuator sensor 238 associated with the brake actuator 236. For example, in... Figure 3In this example, compensator 322 can compensate for the servo or valve response characteristics of brake actuator 236. In another example, compensator 322 can be coupled to multiple brake actuators 236 and actuator sensors 238. In this example, compensator 322 can be used to adjust brake actuator signals 310 sent to multiple brake actuators 236 based on brake actuator command 118, to balance braking among the multiple brake actuators 236.

[0063] exist Figure 3 In the specific example illustrated, in response to brake actuator signal 310, brake actuator 236 causes brake clamp 314 to contact or press against rotor 316, thereby braking wheel 204 and applying torque to structure 202 due to the braking force coupled to structure 202 via support rod 312. Brake torque sensor 126 is coupled to support rod 312, structure 202, or both, to generate brake torque signal 128 representing the braking torque applied to structure 202. In some implementations, the dimensions of support rod 312 are known and the braking torque can be indicated by measuring the braking force applied by brake clamp 314. In such implementations, a force sensor instead of a torque sensor can be used to measure the value representing the braking torque.

[0064] Braking torque signal 128 is provided to fault-tolerant torque system 130. Additionally, in some implementations, braking operating environment sensor 234 provides one or more braking operating environment signals 330 as inputs to fault-tolerant torque system 130. Fault-tolerant torque system 130 evaluates braking torque signal 128 (e.g., based on...) Figure 2 The fault-tolerant torque system 130 uses fault criterion 242 to determine whether a sensor fault condition is detected. If no sensor fault condition is detected, the fault-tolerant torque system 130 provides the braking torque signal 128 to the braking load mitigation system 134. In this case, the braking load mitigation system 134 generates a load mitigation command 136 based on the braking torque signal 128. In some implementations, when no sensor fault is detected, the fault-tolerant torque system 130 also uses the braking torque signal 128, the brake actuator command 118, and the braking operating environment signal 330 to generate model update data to update the braking model 256.

[0065] If the fault-tolerant torque system 130 detects a sensor failure, it provides an estimated braking torque signal 132 to the brake load mitigation system 134. In this case, the brake load mitigation system 134 generates a load mitigation command 136 based on the estimated braking torque signal 132. The fault-tolerant torque system 130 calculates or looks up the estimated braking torque value based on a similar value in response to the brake actuator command 118 and historical braking torque values ​​under similar braking operating conditions (such as those indicated by the brake operating environment signal 330). Additional details regarding the operation of the fault-tolerant torque system 130 are described below.

[0066] Figure 4 This is an example based on a specific implementation. Figures 1 to 3 A diagram of the braking system 100. Specifically, Figure 4 Further details of the fault-tolerant torque system 130 and the fault-tolerant torque system 130 and Figure 2 Interactions between other components of the vehicle 200.

[0067] exist Figure 4 In this configuration, brake pedal sensor 302 sends brake pedal input signal 304 to brake pedal command logic 306. Brake pedal command logic 306 generates a filtered position signal 404 by passing the brake pedal input signal 304 through an anti-aliasing filter 402. Brake pedal command logic 306 applies pedal gain 406 to the filtered position signal 404 to generate brake pedal command 106. Brake pedal command 106 is provided to control circuitry 222, which generates brake actuator command 118 in part based on brake pedal command 106. In some implementations, such as in... Figure 3 In the illustrated example, brake pedal command 106 is also provided to the fault-tolerant torque system 130. For illustration, in such an implementation, brake pedal command 106 can be provided to brake mode detector 424 to facilitate the detection of sensor malfunctions, as discussed further below. In other implementations, such as in... Figure 4 In the example shown, brake actuator command 118 is used for brake mode detection.

[0068] exist Figure 4 In the illustrated example, brake actuator command 118 is sent to brake actuation system 120. Brake actuation system 120 generates braking force (and corresponding braking torque) in response to braking by brake actuator command 118. Braking gain 410 describes the relationship between the value of brake actuator command 118 and the value of braking force or braking torque.

[0069] Braking torque sensor 126 generates a braking torque signal 128 representing the braking torque. Braking torque signal 128 is provided to fault-tolerant torque system 130. Additionally, in some implementations, braking operating environment sensor 234 provides braking operating environment signal 330 to fault-tolerant torque system 130. Figure 4 In the illustrated example, the braking operating environment sensor 234 includes one or more of a brake temperature sensor 412, a wheel temperature sensor 414, a wheel speed sensor 416, or a ground speed sensor 418.

[0070] exist Figure 4 In the example, the fault-tolerant torque system 130 uses a low-pass filter 420 to remove high-frequency components from the braking torque signal 128 to generate a filtered torque signal 422. The filtered torque signal 422, the braking operating environment signal 330, and the brake actuator command 118 (or brake pedal command 106) are provided as inputs to the sensor monitor 240.

[0071] exist Figure 4 In this configuration, sensor monitor 240 includes a braking mode detector 424. Braking mode detector 424 determines whether the braking operation should be evaluated by the fault-tolerant torque system 130. Since the function of the brake load mitigation system 134 is to limit the load applied to a specific structure of the vehicle during braking, factors contributing to the application of load to that specific structure are considered to determine whether the braking operation should be evaluated by the fault-tolerant torque system 130. For example, braking mode detector 424 may consider braking operation environment information determined based on braking operation environment signal 330, such as wheel speed or ground speed. In this example, if the wheel speed or ground speed is less than a threshold, braking mode detector 424 may determine that the fault-tolerant torque system 130 does not need to evaluate the braking operation, in which case the fault-tolerant torque system 130 does not take any further action. As another example, braking mode detector 424 may consider the magnitude of the braking operation, such as that indicated by brake pedal command 106 or brake actuator command 118. In this example, if the magnitude of the braking operation is less than a threshold, the braking mode detector 424 can determine that the fault-tolerant torque system 130 does not need to evaluate the braking operation, and in this case, the fault-tolerant torque system 130 does not take any further action.

[0072] If the braking mode detector 424 determines that the braking operation should be evaluated by the fault-tolerant torque system 130, the sensor monitor 240 compares the braking torque signal 128, the filtered torque signal 422, or both, with the fault criterion 242. Figure 4 In the example, if no fault is detected, valid sensor data 426 is provided to model updater 252, and braking torque signal 128 is provided to braking load mitigation system 134 to generate load mitigation command 136. Alternatively, in Figure 4In the example, if a fault is detected, a fault indication signal 434 is provided to the torque estimator 250, and the torque estimator 250 determines an estimated braking torque signal 132 based on the model output 442. The estimated braking torque signal 132 is provided to the braking load relief system 134 to generate a load relief command 136.

[0073] Valid sensor data 426 includes data from braking torque signal 128 and brake actuator command 118. In some implementations, valid sensor data 426 also includes data from braking operating environment signal 330. Model updater 252 uses valid sensor data 426 to generate model update data 432 to update braking model 256. As an example, model updater 252 stores historical data 428 indicating historical values ​​of valid sensor data 426 (e.g., valid historical braking torque signal values, corresponding brake actuator command values, and corresponding brake temperature values). Model updater 252 adds valid sensor data 426 as one or more data entries in historical data 428, and calculator 430 of model updater 252 determines model update data 432 based on valid sensor data 426 and historical data 428. For example, as referenced... Figure 6 As described, calculator 430 can determine the average or moving average of historical data 428. As another example, calculator 430 can... Figure 8 The feature space 802 is shifted or the surface 812 is modified to generate model update data 432. As another example, the calculator 430 can update the braking gain parameter used by the torque estimation function (e.g., Equation 1 above). In some implementations, historical data 428 (including valid sensor data 426) can be used to update or modify the threshold 508 used by the fault criterion 242, as referenced. Figure 5 As described, model update data 432 is stored in memory 436 to update one or more tables 438 of braking model 256, update one or more parameters 440 of braking model 256, or both.

[0074] The fault indication signal 434 causes the torque estimator 250 to generate an estimated braking torque signal 132 based on the model output 442, which is based on the brake actuator command 118 and the braking model 256. In some implementations, the torque estimator 250 also generates the estimated braking torque signal 132 based on the braking operating environment signal 330. As a first example, when the braking model 256 includes a table 438 or other data structures storing estimated braking torque values ​​for a specific brake actuator command value (such as...), the estimated braking torque signal 132 is generated. Figures 5 to 7As illustrated, when the brake actuator command 118 is used, the torque estimator 250 looks up the estimated value of the brake torque signal 132 from table 438 or other data structures. As a second example, when the brake model 256 includes a function parameter 440 (e.g., the brake gain parameter of Equation 1), the torque estimator 250 calculates the estimated value of the brake torque signal 132 based on the value of the brake actuator command 118 and the brake gain parameter value.

[0075] Figure 9 It is based on a specific implementation. Figures 1 to 4 A flowchart illustrating an example of method 900 implemented by braking system 100. For example, method 900 may be initiated, executed, or controlled by fault-tolerant torque system 130 or one or more of its components.

[0076] Method 900 includes: at block 902, receiving at least a brake actuator command. For example, Figures 1 to 4 The fault-tolerant torque system 130 receives a brake actuator command 118 from the control circuit 222. Method 900 may further include, at block 902, receiving additional signals including a brake torque signal and / or one or more brake operating environment signals. For example, Figures 1 to 4 The fault-tolerant torque system 130 receives a braking torque signal 128 from the braking torque sensor 126 and a braking operating environment signal 330 from the braking operating environment sensor 234. In some cases, the braking torque sensor 126 may experience a fault condition that causes the fault-tolerant torque system 130 to fail to receive the braking torque signal 128 when it is expected (e.g., during braking operations that generate significant braking torque). This condition results in the detection of a fault condition, as discussed further below.

[0077] Method 900 includes performing a braking mode detection at block 904, wherein block 904 includes determining at block 906 whether braking has been applied. For example, the determination of whether braking has been applied may be based on brake pedal command 106 or brake actuator command 118. If it is determined at block 906 that no braking has been applied, method 900 returns to block 902 to await the reception of a subsequent signal.

[0078] If the determination at block 906 indicates that braking has been applied, method 900 continues at block 908 to determine whether the speed of vehicle 200 is greater than a threshold. For example, the wheel speed value or ground speed value from the braking operation environment signal 330 can be compared to the threshold. If the determination at block 908 indicates that the speed of vehicle 200 is less than (or less than or equal to) the threshold, method 900 returns to block 902 to await the reception of subsequent signals. If the determination at block 908 indicates that the speed of vehicle 200 is greater than the threshold, method 900 determines at block 910 whether a fault condition has been detected. In implementations where the braking operation environment sensor 234 is not used to generate the braking operation environment signal 330, the decision at block 908 is omitted.

[0079] If a braking torque signal 128 is received at block 902, determining whether a fault condition is detected at block 910 involves comparing the value indicated by the braking torque signal 128 with fault criterion 242 to determine whether the braking torque signal value is valid. If the value indicated by the braking torque signal 128 is valid (e.g., if the value of the braking torque signal is within the threshold range indicated by fault criterion 242), block 910 indicates that no fault is detected, and method 900 proceeds to block 912. If the value indicated by the braking torque signal 128 is invalid (e.g., if the value of the braking torque signal 128 is outside the threshold range indicated by fault criterion 242), block 910 indicates that a fault is detected, and method 900 proceeds to block 914. Additionally, in some implementations, if a braking torque signal 128 is not received at block 902 when a braking torque signal 128 is expected (e.g., when the braking mode detection in block 904 indicates that braking has been applied and the vehicle is moving at a speed greater than a threshold), block 910 indicates that a fault is detected.

[0080] If the determination at block 910 indicates that no fault condition was detected, then the braking torque signal 128 is considered to include valid sensor data 426, and method 900 includes, at block 912, updating the braking model based on the valid sensor data 426. For example, the valid sensor data 426 may be provided to a model updater 252, which may update the braking model 256.

[0081] If the determination at block 910 indicates that a fault condition has been detected, then method 900 includes, at block 914, generating an estimated braking torque signal 132 based on braking model 256. For example, torque estimator 250 may use braking model 256 and brake actuator command 118 to determine the value of the estimated braking torque signal 132.

[0082] Additionally, if the determination at block 910 indicates that no fault condition is detected, the value indicated by the braking torque signal 128 is provided to the braking load relief system 134. Alternatively, if the determination at block 910 indicates that a fault condition is detected, an estimated braking torque signal 132 is provided to the braking load relief system 134.

[0083] Figure 10 It is based on a specific implementation. Figures 1 to 4 A flowchart of another example of method 1000 implemented by braking system 100. For example, method 1000 may be initiated, executed or controlled by fault-tolerant torque system 130 or its components.

[0084] Method 1000 includes, at block 1002, determining whether a sensor malfunction condition is detected based on a braking torque signal 128 from a braking torque sensor 126. For example, a sensor monitor 240 of a fault-tolerant torque system 130 determines whether a sensor malfunction condition is detected based on the braking torque signal 128 from the braking torque sensor 126. In some implementations, the fault-tolerant torque system 130 also uses other data to determine whether a sensor malfunction condition is detected, such as the value of a brake pedal command 106, the value of a brake actuator command 118, the value of a brake operating environment signal 330, or a combination thereof.

[0085] Method 1000 includes: when it is determined at block 1004 that no sensor fault condition is detected, at block 1012, generating a braking actuation signal based on the braking torque signal. For example, as Figure 3 As shown, when there is no sensor malfunction, the fault-tolerant torque system 130 provides a braking torque signal 128 to the braking load relief system 134, and the braking load relief system 134 generates a load relief command 136 based on the braking torque signal 128. In this example, the control circuit 222 uses the load relief command 136 and the brake pedal command 106 to generate a brake actuator command 118. Therefore, in this case, the brake actuator command 118 is based on the braking torque signal 128.

[0086] Method 1000 includes: when a sensor fault condition is detected at block 1004, accessing a braking model from memory accessible to the braking system control unit at block 1006. For example, Figure 2 The braking system control unit 220 accesses the braking model 256. In some implementations, for example... Figures 5 to 7As illustrated, braking model 256 includes multiple data entries representing historical braking torque values ​​506 corresponding to various brake actuator command values ​​502. In some such implementations, the multiple data entries also include one or more default braking torque values ​​504, each of which represents the braking torque used for a corresponding braking command value, until a sufficient number of historical braking torque values ​​506 have been accumulated. In other implementations, braking model 256 includes a parameter 440 of a braking gain function (e.g., Equation 1), and the value of parameter 440 of the braking gain function is based on historical braking torque values ​​and corresponding braking command values. In some such implementations, an initial parameter value or a default parameter value of parameter 440 can be used until parameter 440 is updated to generate updated parameter values ​​based on model update data 432.

[0087] Method 1000 further includes, at block 1008, generating an estimated braking torque signal 132 based on braking model 256 and braking actuator command 118. For example, torque estimator 250 generates the estimated braking torque signal 132 based on braking model 256 and braking actuator command 118. Braking actuator command 118 is generated in such a way that the load applied to structure 202 of vehicle 200 due to braking is limited to less than a specified load limit. In some implementations, the estimated braking torque value of estimated braking torque signal 132 is determined by interpolation between braking torque values ​​from braking model 256.

[0088] Method 1000 further includes: at block 1010, generating a load relief command 136 based on the estimated braking torque signal 132. For example, as Figures 1 to 4 As shown, when a sensor malfunction is detected, the brake load reduction system 134 generates a load reduction command 136 based on the estimated brake torque signal 132.

[0089] Therefore, when a sensor is present, method 1000 allows the operation of the brake load mitigation system to continue. The disclosed fault-tolerant brake load mitigation system and method use a vehicle-specific braking model that is generated and / or updated in the absence of sensor failure to generate an estimated braking torque signal 132 when the braking torque signal 128 is unavailable or unreliable (e.g., due to sensor failure). Because the braking model is tailored to a specific vehicle, the estimated braking torque signal 132 reliably limits the load on the vehicle structure, thereby enabling the vehicle to operate without imposing additional operational restrictions (e.g., operating weight restrictions or braking distance restrictions).

[0090] Figure 11 This is an example indicating that includes Figure 2The flowchart illustrates a method 1100 for the lifecycle of a vehicle comprising structure 202, sensor 230, and braking system control unit 220. The vehicle may include an aircraft or a land vehicle.

[0091] During pre-production, exemplary method 1100 includes: at 1102, a vehicle (e.g., Figure 2 Vehicle 200 or Figure 12 The specifications and design of the aircraft (1200). During the specification and design of the vehicle, method 1100 may include: the specification and design of structure 202, sensor 230, and braking system control unit 220. Method 1100 includes: material procurement at 1104, which may include procuring materials for structure 202, sensor 230, and braking system control unit 220.

[0092] During production, method 1100 includes: component and sub-assembly manufacturing at 1106 and system integration of the vehicle at 1108. For example, method 1100 may include component and sub-assembly manufacturing of structure 202, sensor 230, and braking system control unit 220, as well as system integration of structure 202, sensor 230, and braking system control unit 220. Method 1100 includes: certifying and delivering the vehicle at 1110, and putting the vehicle into service at 1112. Certification and delivery may include certifying structure 202, sensor 230, and braking system control unit 220 to put them into service. During customer service, the vehicle may be scheduled for routine maintenance and servicing (which may also include modification, reconfiguration, refurbishment, etc.). Method 1100 includes: performing maintenance and servicing on the vehicle at 1114, which may include performing maintenance and servicing on structure 202, sensor 230, and braking system control unit 220.

[0093] Each process of Method 1100 may be performed or executed by a system integrator, a third party, and / or an operator (e.g., a customer). For the purposes of this specification, a system integrator may include, but is not limited to, any number of manufacturers and major system subcontractors; a third party may include, but is not limited to, any number of vendors, subcontractors, and suppliers; and an operator may be an airline, leasing company, military entity, service provider, etc.

[0094] Aspects of this disclosure can be described in the context of vehicle examples. Specific examples of vehicles are as follows: Figure 12 The aircraft shown is 1200.

[0095] exist Figure 12In the example, aircraft 1200 includes a fuselage 1250, which includes a structure 202. Aircraft 1200 also includes multiple systems 1220 and an interior 1252. Examples of the multiple systems 1220 include one or more of a propulsion system 1222, an electrical system 1224, an environmental system 1226, a hydraulic system 1228, and a braking system 100. Braking system 100 includes... Figure 2 The sensor 230 and braking system control unit 220 are included. The aircraft 1200 may also include any number of other systems.

[0096] In some implementations, non-transitory computer-readable media store instructions that, when executed by one or more processors, cause one or more processors to initiate, execute, or control operations to perform some or all of the functions described above. For example, the instructions can be executed to implement Figures 1 to 10 One or more of the operations or methods. In some implementations, Figures 1 to 10 One or more of the operations or methods may be implemented by one or more processors (e.g., one or more central processing units (CPUs), one or more graphics processing units (GPUs), one or more digital signal processors (DSPs)) executing instructions, by dedicated hardware circuitry, or any combination thereof.

[0097] The examples described herein are intended to provide a general understanding of the structure of various implementations. The examples are not intended as a complete description of all elements and features of apparatuses and systems utilizing the structures or methods described herein. Many other implementations may become apparent to those skilled in the art upon review of this disclosure. Other implementations can be utilized and derived from this disclosure, allowing for structural and logical substitutions and changes without departing from the scope of this disclosure. For example, method operations may be performed in a different order than those shown in the figures, or one or more method operations may be omitted. Therefore, this disclosure and the accompanying drawings are to be considered illustrative rather than restrictive.

[0098] Furthermore, while specific examples have been illustrated and described herein, it should be understood that any subsequent arrangements designed to achieve the same or similar results may replace the specific implementations shown. This disclosure is intended to cover any and all subsequent adaptations or variations of the various implementations. Combinations of the above implementations and other implementations not specifically described herein will be apparent to those skilled in the art upon review of the description.

[0099] This abstract of disclosure is provided so that it will not be used to interpret or limit the scope or meaning of the claims. Furthermore, in the specific embodiments described above, various features may be combined together or described in a single implementation for the purposes of this disclosure. The examples above are illustrative but not limiting of this disclosure. It should also be understood that many modifications and variations are possible based on the principles of this disclosure. As reflected in the appended claims, the claimed subject matter may involve fewer features than those in any of the disclosed examples. Therefore, the scope of this disclosure is defined by the appended claims and their equivalents.

Claims

1. A braking system control unit (220), the braking system control unit (220) comprising: One or more sensor interfaces (224) are configured to receive a braking torque signal (128) from a braking torque sensor (126). A torque estimator (250) is configured to generate an estimated braking torque signal (132) based at least in part on a braking model (256) and a braking actuator command (118). as well as A control circuit (222) is configured to generate the brake actuator command to actuate the brake actuator (236) of the braking system (100), wherein the brake actuator command is generated based on a brake pedal command (106) and a load relief command (136), and wherein the load relief command is based on the brake torque signal or the estimated brake torque signal, depending on whether a sensor malfunction condition associated with the brake torque sensor is detected.

2. The braking system control unit according to claim 1, further comprising: A model updater (252) is configured to update the braking model by storing model update data (432) when no sensor fault condition associated with the braking torque sensor is detected, the model update data (432) associating the brake actuator command value from the brake actuator command with the brake torque value from the brake torque signal.

3. The braking system control unit according to claim 2, wherein, The one or more sensor interfaces are also configured to receive sensor data from one or more braking operating environment sensors (234), and wherein the model update data also associates the brake actuator command value and the braking torque value with braking operating environment values ​​from the sensor data.

4. The braking system control unit according to claim 3, wherein, The one or more braking operation environment sensors measure one or more of ground speed, wheel speed, wheel temperature, and brake temperature.

5. The braking system control unit according to claim 1, wherein, The braking model includes one or more tables (438), each table including multiple braking torque values ​​(602) and corresponding multiple braking actuator command values, wherein the estimated braking torque signal is determined at least in part based on the braking actuator command values ​​from the braking actuator commands by looking up a specific braking torque value in the one or more tables.

6. The braking system control unit according to claim 1, further comprising a sensor monitor (240) configured to detect sensor malfunction based on a comparison of a measured braking torque value of the braking torque signal with one or more fault criteria (242).

7. The braking system control unit according to claim 6, wherein, At least one of the one or more fault criteria is based on one or more historical braking torque values ​​(506) and one or more brake actuator command values ​​associated with the one or more historical braking torque values.

8. The braking system control unit according to claim 1, wherein, The control circuit is also configured to generate the braking actuator command such that the load applied to the structure (202) of the aircraft (1200) due to braking is less than a specified load limit (254).

9. The braking system control unit according to claim 1, wherein, The braking model includes one or more data tables (438), and each of the one or more data tables includes a sliding average of historical braking torque values ​​(506) for each of the plurality of brake actuator command values.

10. The braking system control unit according to claim 1, wherein, The braking model includes parameters (440) of the braking gain function, wherein the parameters are based on one or more historical braking torque values.

11. The braking system control unit according to claim 1, wherein, The torque estimator is configured to generate the estimated braking torque signal using default parameter values ​​of the braking model during a first time period, and is configured to generate the estimated braking torque signal using updated parameter values ​​of the braking model during a second time period after the first time period, wherein the default parameter values ​​are based on test data, and wherein the updated parameter values ​​are based on sensor data values ​​from the braking system.

12. The braking system control unit according to claim 1, wherein, The braking model is configured to indicate the estimated braking torque value based on the value of the brake actuator command and the braking operating environment value.

13. A method (1000) for reducing braking load, the method comprising the following steps: At the brake system control unit, it is determined (1002) whether a sensor malfunction condition is detected based on the brake torque signal (128) from the brake torque sensor (126); In response to the detection of the sensor malfunction: Access (1006) the braking model (256) from the memory (436) accessible by the braking system control unit. Based on the braking model and brake actuator command (118), generate (1008) an estimated braking torque signal (132); and The estimated braking torque signal is used to generate a load reduction command (136) (1010).

14. The method of claim 13, further comprising the step of: In response to the absence of a detected sensor malfunction, the load reduction command is generated (1012) based on the braking torque signal.

15. The method according to claim 13, wherein, The braking model includes multiple data entries, which represent historical braking torque values ​​(506) corresponding to various brake actuator command values ​​(502).

16. The method according to claim 15, wherein, The plurality of data entries also include one or more default data entries (504), wherein each of the one or more default data entries represents a default braking torque value corresponding to a corresponding brake actuator command value.

17. The method according to claim 13, wherein, The braking model includes parameters (440) of a braking gain function, wherein the values ​​of the parameters of the braking gain function are based on historical braking torque values ​​and corresponding braking actuator command values.

18. The method according to claim 13, wherein, The estimated braking torque value of the estimated braking torque signal is determined by interpolation between historical braking torque values ​​from the braking model.

19. The method of claim 13, further comprising the step of: The brake pedal command is determined based on the brake pedal sensor (302).

20. The method according to claim 13, wherein, The braking actuator command is generated in such a way that the load applied to the structure (202) of the aircraft (1200) due to braking is limited to less than a specified load limit (254).

21. A vehicle (200) comprising: One or more wheels (204) are connected to the structure (202); One or more braking systems (100), each braking system (100) including one or more sensors (230) and one or more brake actuators (236); as well as One or more braking system control units (220), each braking system control unit (220) including: One or more sensor interfaces (224) are configured to receive a braking torque signal (128) from a braking torque sensor (126). A torque estimator (250) configured to generate an estimated braking torque signal (132) based at least in part on a braking model (256) and a brake actuator command (118); and A control circuit (222) is configured to generate the brake actuator command to actuate one or more of the brake actuators, wherein the brake actuator command is generated based on a brake pedal command (106) and a load relief command (136), and wherein the load relief command is based on the brake torque signal or the estimated brake torque signal.

22. The vehicle according to claim 21, further comprising: At least one of the automatic braking system (212) and anti-skid system (214) connected to the one or more braking system control units, wherein the brake actuator command is based at least in part on a signal (114) from at least one of the automatic braking system and the anti-skid system.

23. The vehicle according to claim 21, wherein, The one or more braking system control units include a braking load reduction system (134) configured to generate the load reduction command to limit the load applied to a portion of the structure due to braking to less than a specified load limit (254).

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