Determining the weight and balance of an aircraft and oscillating the shock struts of the aircraft to release a portion of the static friction force acting on the shock struts

Abstract

The present application relates to determining an aircraft weight and shaking a shock strut of an aircraft prior to balancing to release a portion of static friction acting on the shock strut. A system for an aircraft includes a shock strut of a landing gear. The system includes one or more excitation devices coupled to the shock strut. The one or more excitation devices are configured to shake the shock strut to enable the shock strut to transition from a first static state, in which an outer cylinder of the shock strut is stationary relative to an inner cylinder of the shock strut, to a dynamic state, in which the outer cylinder is moving relative to the inner cylinder, and from the dynamic state to a second static state. The system further includes a resonance system coupled to the one or more excitation devices. The resonance system is configured to provide a first signal to the one or more excitation devices to activate the one or more excitation devices to shake the shock strut.

Description

Technical Field

[0001] This disclosure generally relates to a portion of vibrating the shock absorber struts of an aircraft to release static friction forces acting on the struts before determining the aircraft's weight and balance. Background Technology

[0002] Aircraft weight and balance are factors affecting aircraft functionality. Aircraft weight and balance influence many factors associated with flight, including fuel requirements, runway length for takeoff and landing, horizontal stabilizer settings, handling characteristics, operational and performance parameters, etc. Commercial aircraft require weight and balance checks before each flight. The vast majority of commercial airlines and cargo operations rely on load masters to perform these checks. Weight and balance checks are based on the empty weight associated with the aircraft without passengers, crew, and cargo; fuel quantity; weighed cargo; estimated cargo weight; estimated passenger and crew weight and estimated baggage weight based on passenger and crew counts; other estimates; and combinations thereof. The aim is to reduce inaccuracies arising from the use of estimated weights based on one or more measurable conditions associated with the aircraft.

[0003] Weight scales can be used to determine the weight and balance of an aircraft. However, it is impractical to have weight scales at every loading and unloading point of an aircraft due to cost, increased turnaround time, maintenance requirements, and other factors. Systems that enable the determination of an aircraft's weight and balance without the use of weight scales (e.g., onboard and offboard weight and balance systems that receive input data transmitted from the aircraft and return output to the aircraft) are available, but such systems may require significant adjustments and maintenance. Many operators have disabled such systems due to the additional time and costs incurred from the unreliability associated with their functionality and accuracy. Aircraft with shock absorbers (e.g., passenger or cargo aircraft including landing gear systems with oleo-pneumatic shock absorbers) are expected to include systems configured to release a portion of the static friction in the shock absorbers through vibration before determining the aircraft's weight and balance, thereby facilitating accurate determination of the aircraft's weight and balance. Summary of the Invention

[0004] In a particular embodiment, a system for an aircraft includes a shock strut for landing gear. The system includes one or more excitation devices coupled to the shock strut. The one or more excitation devices are configured to vibrate the shock strut such that the shock strut can transition from the first static state to a dynamic state and from the dynamic state to the second static state, in which the outer cylinder of the shock strut is stationary relative to the inner cylinder of the shock strut, and in the dynamic state, the outer cylinder moves relative to the inner cylinder. The system also includes a resonant system coupled to the one or more excitation devices. The resonant system is configured to provide a first signal to the one or more excitation devices to activate the one or more excitation devices to vibrate the shock strut.

[0005] In another specific embodiment, an aircraft includes a plurality of landing gears. Each of the plurality of landing gears includes a shock absorber strut. The aircraft includes one or more excitation devices coupled to each shock absorber strut. The one or more excitation devices coupled to a particular shock absorber strut are configured to vibrate the particular shock absorber strut to enable the particular shock absorber strut to transition from a first static state to a dynamic state and from a dynamic state to a second static state, in which the outer cylinder of the particular shock absorber strut is stationary relative to the inner cylinder of the particular shock absorber strut, and in the dynamic state, the outer cylinder moves relative to the inner cylinder. The aircraft also includes one or more resonant systems coupled to the excitation devices. The one or more resonant systems are configured to provide a first signal to the excitation devices to activate the excitation devices to vibrate the shock absorber strut.

[0006] In another specific embodiment, a method includes receiving a request at a computer system of an aircraft to determine the weight of the aircraft. The aircraft includes a plurality of landing gears. Each of the plurality of landing gears includes a shock absorber strut. Furthermore, one or more excitation devices are coupled to each shock absorber strut. The one or more excitation devices coupled to a particular shock absorber strut are configured to vibrate the particular shock absorber strut to enable the particular shock absorber strut to transition from a first static state to a dynamic state and from a dynamic state to a second static state, in which the outer cylinder of the particular shock absorber strut is stationary relative to the inner cylinder of the particular shock absorber strut, and in the dynamic state, the outer cylinder moves relative to the inner cylinder. The method also includes, in response to the request, causing one or more resonant systems via the computer system to send a first signal to the excitation devices to activate the excitation devices to vibrate the shock absorber strut.

[0007] The features, functions and advantages described herein may be implemented independently in various embodiments or in combination in other embodiments, further details of which can be found in the following description and figures. Attached Figure Description

[0008] Figure 1 This is a block diagram of an aircraft.

[0009] Figure 2 A side view representation of the aircraft is depicted.

[0010] Figure 3 This is a flowchart of an implementation of a method that uses the aircraft's computer system to cause vibration of the damping struts to release static friction forces acting on the damping struts before determining the aircraft's weight and balance.

[0011] Figure 4 This is a flowchart illustrating the lifecycle of an aircraft.

[0012] Figure 5 It is a block diagram of a computing environment including a computing device configured to support aspects of computer-implemented methods and computer-executable program instructions (or code) according to the present disclosure. Detailed Implementation

[0013] This disclosure describes vibrating the oleo shock struts of an aircraft before determining its weight and balance to release a portion of the static friction forces acting on the struts. The aircraft carries passengers, cargo, or both, and includes multiple landing gears, each with an oleo shock strut. The oleo shock strut acts as a spring and damper system, wherein (1) the compression and expansion of a gas (e.g., nitrogen) behaves like a spring, and (2) a fluid (e.g., hydraulic fluid) passing through an orifice plate acts as a damper to accommodate the forces applied to the aircraft associated with landing and taxiing through heat generation and dissipation.

[0014] A weight and balance system determines the weight and balance of an aircraft. In some embodiments, the weight and balance system is an onboard weight and balance system that utilizes the aircraft's computer system to determine the aircraft's weight and balance based on sensor data and provides a first output associated with the weight and balance to one or more output devices. In other embodiments, the weight and balance system is an offboard weight and balance system. An offboard weight and balance system utilizes an external computer system to receive sensor data from the aircraft via a communication system, processes the sensor data to determine the aircraft's weight and balance, and provides the weight and balance as output to the aircraft's computer system. The aircraft's computer system provides a first output associated with the weight and balance to one or more output devices.

[0015] The weight of an aircraft is the sum of the vertical forces between the ground and each landing gear unit. Based on the vertical forces on the landing gear, the weight of the aircraft, and the effective contact area between the landing gear and the ground, as well as the axial distance between the landing gear and a reference point, the aircraft's balance is determined relative to one or more centers of gravity (CG) relative to the reference point. The weight and balance of the aircraft are determined based on the loads on the landing gear struts. The loads on the struts are determined based on the air pressure within the struts when they are in a static state after the transition from a dynamic to a static state, to allow calculations to compensate for the presence of static friction in the struts.

[0016] Each shock absorber strut of an aircraft's landing gear system supports a portion of the aircraft's weight. Each shock absorber strut includes an inner cylinder positioned within an outer cylinder, with gas residing in a chamber within the outer cylinder. The outer cylinder is coupled to a first support structure attached to the aircraft's fuselage. The inner cylinder is coupled to a second support structure (e.g., a wheel assembly) in contact with the ground. A torsion bar is pivotally coupled to the inner cylinder, the outer cylinder, and each other to prevent rotation of the inner cylinder relative to the outer cylinder, while still allowing the outer cylinder to move toward or away from the inner cylinder. Movement of the outer cylinder toward the inner cylinder results in compression of the gas, and movement of the outer cylinder away from the inner cylinder results in expansion of the gas. In other embodiments, the shock absorber struts, support structures, or both may have different configurations.

[0017] For a frictionless damping strut, changes in the load on the outer cylinder cause movement of the inner cylinder relative to the outer cylinder, and a corresponding change in the air pressure within the damping strut. The load on the damping strut is equal to the initial force exerted by the gas on it. This initial force is equal to the air pressure ( P ) multiplied by the surface area of ​​the applied force associated with the outer cylinder of the shock absorber strut ( A (The gas acts on the outer cylinder), and is orthogonal to the direction of travel of the outer cylinder relative to the inner cylinder. For frictionless gas struts, the change in gas pressure in the shock-absorbing strut due to temperature changes also causes the outer cylinder to move relative to the inner cylinder.

[0018] Real-world vibration damping struts are typically not frictionless systems. When a vibration damping strut is in a static state, changes in the load on it or changes in pressure within it due to temperature variations lead to changes in the static friction force acting on it. When the static friction force does not reach the point of breaking friction (e.g., the compression breaking friction force when the load increases and the expansion breaking friction force when the load decreases), the vibration damping strut remains in a static state, with the outer cylinder stationary relative to the inner cylinder, and the air pressure within the strut does not change unless there is a temperature change in the gas within the strut. The load on the vibration damping strut is induced by the first force caused by the air pressure within the strut (i.e.,... P Multiply AThe static friction force is supported by static friction. When the first force is less than the load on the shock absorber strut, the static friction force is a positive compressive static friction force; when the first force is equal to the load on the shock absorber strut, the static friction force is zero; and when the first force is greater than the load on the shock absorber strut, the static friction force is a negative expansive static friction force. When the breakthrough friction force is reached, the static friction force becomes dynamic friction force, and the outer cylinder moves relative to the inner cylinder.

[0019] Static friction can be high before reaching the breakthrough friction force. For example, for the nose landing gear strut of an aircraft weighing approximately 700,000 pounds, the compressive static friction may exceed 10,000 pounds (lbs) before the load added to the strut causes the compressive static friction to reach the breakthrough friction force. Similarly, for the main landing gear strut, the compressive static friction may exceed 52,000 pounds before the load added to the strut causes the compressive static friction to reach the breakthrough friction force. Determining an aircraft's weight and balance solely based on the air pressure within its struts without compensating for the struts' static friction can lead to significant errors.

[0020] When the load on the damper strut causes the static friction to exceed the compressive friction (i.e., an increase in load causes the static friction to exceed the compressive friction, or a decrease in load causes the static friction to exceed the expansive friction), the damper strut transitions from a first static state to a dynamic state, causing the outer cylinder to move relative to the inner cylinder, and a change in air pressure within the damper strut. This movement of the outer cylinder relative to the inner cylinder is a result of an imbalance between the load and the forces resisting the load, which are the first force caused by the air pressure within the damper strut and the dynamic friction between the outer and inner cylinders. The damper strut remains in the dynamic state until it transitions to a second static state, at which point the movement of the inner cylinder relative to the outer cylinder ceases, as the load is balanced by the first force caused by the air pressure within the damper strut plus the dynamic friction. At the transition between the dynamic and static states, the dynamic friction instantaneously transforms into static friction, and the dynamic friction is identical to the static friction, which is referred to herein as the friction at the dynamic-static transition. The frictional forces at the dynamic-to-static transition point are compressive friction when the air pressure in the damper strut increases during the dynamic state, and expansive friction when the air pressure in the damper strut decreases during the dynamic state. After transitioning to the second static state, the damper strut remains in the second static state until the static friction reaches another breakthrough frictional force due to changes in load, changes in static friction caused by temperature changes, or both.

[0021] The breakthrough friction of the strut after the transition to a dynamic state due to load changes is detectable (e.g., based on analysis of pressure data, orientation data associated with the outer and inner cylinders, or both), varies with the load on the strut (e.g., the first compression breakthrough friction for low load and low pressure is greater than the second compression breakthrough friction for high load and high pressure), is not always repeatable, and is difficult to predict accurately. The dynamic-static transition is detectable (e.g., based on analysis of pressure data, orientation data, or both), repeatable, and the load on the strut can be determined with acceptable accuracy based on measurable conditions (e.g., pressure, gas temperature, or both) by compensating for the static friction at the dynamic-static transition. At the dynamic-static transition of a particular strut, when the gas temperature in the strut is within a specific temperature range, the load can be determined solely based on pressure (i.e., pressure, gas temperature, or both). P Multiply A The load determined on the damping strut is within approximately 2.5% of the actual load on the damping strut (e.g., the load determined using a calibrated weight scale).

[0022] A correction factor applied to the load determined based on the pressure at the dynamic-static transition (e.g., a 2.5% correction to account for static friction at the dynamic-static transition when the gas temperature in the strut is within a specific temperature range) improves the accuracy of the determined load and subsequent values ​​(e.g., the weight and balance of the aircraft) based on the load. The correction factor results in a higher load when the dynamic state prior to the dynamic-static transition indicates that the friction at the transition is compressive friction, and a lower load when the dynamic state prior to the transition indicates that the friction at the transition is expansive friction. The correction factor can be adjusted for operation under very cold or very hot conditions (e.g., gas temperatures in the strut below -15 degrees Celsius or above 35 degrees Celsius). In some embodiments, experimentally determined correction factors for the aircraft at different temperatures, empirically determined correction factors for different temperatures, or both are stored in a table and utilized when performing calculations to determine the weight of the aircraft. When the current temperature does not correspond to a temperature in the table, interpolation techniques (e.g., linear interpolation) can be used to determine the correction factor.

[0023] Before determining the weight and balance of the aircraft, the aircraft undergoes one or more actions configured to cause the shock absorber struts to transition from a first static state to a dynamic state and from a dynamic state to a second static state. One or more actions may include applying vibration to the shock absorber struts to cause them to undergo transitions from the first static state to the dynamic state and from the dynamic state to the second static state; applying mechanical forces to the shock absorber struts that cause the outer cylinder to travel relative to the inner cylinder upon removal (e.g., applying a force to a torsion link of the shock absorber strut coupled to the outer cylinder using a jack or actuator, such that the outer cylinder moves relative to the inner cylinder when the force is released); changing the pressure in each gas strut by adding or removing gas or fluid until the outer cylinder of the shock absorber strut begins to move relative to the inner cylinder; gliding the aircraft to induce forces applied to the shock absorber struts that cause the outer cylinder to move relative to the inner cylinder, and so on. Applying vibration to the shock absorber strut to cause the outer cylinder to travel relative to the inner cylinder provides the system with several advantages over other actions, including the elimination of the need to perform one or more tasks after the action (e.g., moving the aircraft to a location and adding or releasing gas or fluid from the gas strut), less weight added to the aircraft (compared to the weight and modifications required by systems that apply mechanical force to the shock absorber strut and systems that change pressure by adding and / or releasing gas or fluid from the shock absorber strut), less modification to the landing gear, and no human intervention required (aside from the input to start the action).

[0024] Before determining the weight and balance of the aircraft, one or more excitation devices are coupled to the outer cylinder of each damper strut and a first signal is provided to the excitation devices to cause vibration of the excitation devices. The vibration of the damper strut by the one or more excitation devices causes axial, circumferential, radial, or a combination thereof propagation of vibration within the outer cylinder. The first signal sent to the one or more excitation devices of the damper strut includes one or more frequencies that cause resonance in the outer cylinder, which increases the amplitude of the vibration applied to the outer cylinder by the one or more excitation devices. The damping ratio of the outer cylinder allows resonance without a sufficiently large steady-state change in amplitude to affect the sealing of the damper strut or otherwise damage the damper strut.

[0025] The resonance of the outer cylinder of the damping strut makes its behavior more like a frictionless damping strut, creating reduced compressive breakthrough friction and increased expansionary breakthrough friction associated with the strut. The damping strut is designed such that, over a wide pressure range, the reduced compressive breakthrough friction when the outer cylinder vibrates is slightly higher than, at, or slightly lower than the compressive friction at the dynamic-static transition point when the excitation device is not activated, and that, over a wide pressure range, the increased expansionary breakthrough friction when the outer cylinder vibrates is slightly higher than, at, or slightly lower than the expansionary friction corresponding to the dynamic-static transition point when the excitation device is not activated.

[0026] When one or more excitation devices coupled to the shock absorber strut are activated, the outer cylinder moves relative to the inner cylinder when the static friction force is greater than or equal to the decreasing compressive breakthrough force or when the static friction force is less than or equal to the increasing expansion breakthrough force. When movement of the outer cylinder relative to the inner cylinder of the shock absorber strut is detected, activation of one or more excitation devices for the shock absorber strut is stopped, and the outer cylinder continues to move relative to the inner cylinder until a dynamic-to-static transition occurs for the shock absorber strut. The loads on the shock absorber strut are determined using appropriate correction factors based on the behavior during the dynamic state prior to the dynamic-to-static transition. If the outer cylinder moves towards the inner cylinder and the air pressure increases during the dynamic state, the friction force at the dynamic-to-static transition is compressive friction; and if the outer cylinder moves away from the inner cylinder and the air pressure decreases, the friction force at the dynamic-to-static transition is expansion friction. The loads on the shock absorber struts of each landing gear after subjecting the shock absorber struts to vibration are used to determine the vertical loads on the landing gear, and the vertical loads on the landing gear are used to determine the weight and balance of the aircraft.

[0027] When one or more excitation devices coupled to the damper strut are activated, the outer cylinder remains stationary relative to the inner cylinder as the static friction force is between decreasing compressive breakthrough friction and increasing expansion breakthrough friction. In response to the damper strut remaining in a static state, when vibration is applied to the damper strut, the damper strut may undergo one or more iterations of additional vibrations of greater amplitude, longer duration, or both, to determine whether the damper strut will undergo a dynamic-static transition.

[0028] If one or more iterations result in a dynamic state and a corresponding dynamic-static transition, an appropriate correction factor is used to determine the vertical load on the landing gear based on whether the friction at the dynamic-static transition is compressive or expansive friction. If one or more iterations do not result in a dynamic state and a corresponding dynamic-static transition for one or more damping struts, the friction is determined for one or more damping struts based on the response of other damping struts to the applied vibration caused by the excitation device or based on the most recent dynamic-static transition that occurred before the activation of the excitation device. For example, if the first damping strut of the first main landing gear is stationary during the vibration of the damping strut, and the second damping strut of the second main landing gear changes to a dynamic state and the friction at the dynamic-static transition is determined to be expansive friction, the same correction factor used to determine the vertical load on the second main landing gear (e.g., a correction factor of -0.025) is used to determine the vertical load on the first main landing gear. In some embodiments, no correction factor is determined based on the behavior of other damping struts to determine the damping strut that remains stationary during the vibration of the damping strut. For example, if the first damping strut of the nose landing gear is stationary during the vibration of the damping strut, the use of a correction factor in determining the vertical load on the nose landing gear can be ignored because the magnitude of the vertical load on the nose landing gear is much smaller than that on the main landing gear, and the larger error associated with the nose landing gear will not have a significant impact on the errors associated with the aircraft's weight and balance. The aircraft's output weight and balance may include markers or warnings indicating which damping struts have not undergone a dynamic-to-static transition due to activation of the excitation equipment, indications that the weight and balance may have greater errors due to the damping strut(s) that have not undergone a dynamic-to-static transition, or both.

[0029] The aircraft's weight and balance unit obtains the aircraft's weight and balance. In embodiments where the weight and balance unit is an onboard weight and balance system, the weight and balance unit determines the weight and balance based on input data determined from sensor data and parameters associated with the aircraft. In embodiments where the weight and balance unit obtains the weight and balance from an external weight and balance system, the weight and balance unit provides input data to the external weight and balance system, and the aircraft's weight and balance are provided as outputs from the external weight and balance system.

[0030] The weight and balance unit provides the aircraft's weight and balance, obtained from the weight and balance unit, as data to one or more of the aircraft's flight computers. After the aircraft's load / unload cycle is completed, the aircraft's pilot can access the aircraft's weight and balance, presented as graphical images, numerical values, or a combination thereof. Based on the aircraft's weight, the pilot can determine whether the fuel load is appropriate for the aircraft and, if necessary, add more fuel or remove some fuel. When the aircraft's weight, balance, or both exceed weight and balance limits, the flight computers (one or more) can also provide warnings to the aircraft's pilot via visual output, audio output, tactile output, or a combination thereof.

[0031] Additionally, the onboard weight and balance unit can provide the obtained weight and balance to the loading supervisor responsible for loading / unloading the aircraft. The loading supervisor determines an estimate of the weight and balance and compares the estimated weight and balance with the weight and balance provided by the weight and balance unit. If there is a significant difference between the weight and balance values ​​determined by the loading supervisor and the values ​​provided by the onboard weight and balance system, the loading supervisor and / or pilot can resolve the cause of the difference before releasing the aircraft for flight.

[0032] The technical advantage of vibrating the aircraft's struts to release a portion of the static friction acting on them before determining the aircraft's weight and balance using a weight and balance unit is that the weight and balance unit provides a repeatable, reliable, and accurate determination of the aircraft's weight and CG while the aircraft is at the gate or stand without requiring a weighing scale. The accuracy of the determined weight can consistently be within approximately 3%, 2.5%, or 1% of the aircraft's actual weight. Vibration of the struts is accomplished by activating an excitation device coupled to the struts. The technical advantage of using an excitation device to vibrate the struts before determining the aircraft's weight and balance is that the system is relatively lightweight and simple (compared to systems that induce a dynamic state in the struts by adjusting air pressure or applying mechanical forces to the struts to allow relative movement of the strut cylinders when the mechanical forces are removed), and using an excitation device does not require additional personnel as much as moving the aircraft to cause movement of the outer cylinder of the strut relative to the inner cylinder.

[0033] The accompanying drawings and the following description illustrate specific exemplary embodiments. It should be understood that those skilled in the art will be able to design various arrangements, which, although not explicitly described or shown herein, embody the principles set forth herein and are included within the scope of the claims accompanying 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.

[0034] This document describes specific embodiments with reference to the accompanying drawings. Throughout the description, common features are identified by common reference numerals. In some drawings, multiple instances of a particular type of feature are used. Although these features are physically and / or logically different, the same reference numerals are used for each feature, and different instances are distinguished by adding letters to the reference numerals. When this document refers to a feature as a group or a type (e.g., when no specific feature is referred to), reference numerals are used without distinguishing letters. However, when this document refers to a specific feature among multiple features of the same type, reference numerals are used along with distinguishing letters. For example, referencing… Figure 2 Multiple landing gears 104 are shown and associated with reference numerals 104A-104C. When referring to a specific one of the landing gears 104 (e.g., landing gear 104A), the distinguishing letter "A" is used. However, when referring to any one of these landing gears 104, reference numeral 104 is used without the distinguishing letter.

[0035] As used herein, various terms are used only for the purpose of describing particular embodiments and are not intended to be limiting. For example, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Furthermore, some features described herein are singular in some embodiments and plural in others. For illustration, Figure 1 An aircraft 100 comprising one or more resonant systems 128 is depicted, indicating that in some embodiments, the aircraft 100 includes a single resonant system 128, and in other embodiments, the aircraft 100 includes multiple resonant systems 128. For ease of reference herein, these features are generally introduced as “one or more features”, where the description of a feature is used instead of “features” (e.g., a computer system), and subsequent references to “(one or more) feature(s)”, where the description of a feature is used instead of a feature (e.g., (one or more) computer systems), unless intended for a particular singular or plural feature.

[0036] The terms “comprise,” “comprises,” and “comprising” are used interchangeably with “include,” “includes,” or “including.” Additionally, the term “wherein” is used interchangeably with the term “where.” As used herein, “exemplary” indicates an example, implementation, and / or aspect and should not be construed as restrictive or indicating a preference or preferred implementation. As used herein, ordinal numbers (such as “first,” “second,” “third,” etc.) used to modify elements (such as structures, components, operations, etc.) do not themselves indicate any priority or order of that element relative to another element, but merely distinguish that element from another element with the same name (if no ordinal number is used). As used herein, the term “set / group” refers to a grouping of one or more elements, and the term “multiple” refers to multiple elements. As used herein, A “and / or” B may mean “A and B” or “A or B,” or both “A and B” and “A or B” are applicable or acceptable.

[0037] As used herein, unless the context otherwise indicates, “generate,” “calculate,” “use,” “select,” “access,” and “determine” are interchangeable. For example, “generate,” “calculate,” or “determine” a parameter (or signal) can refer to actively generating, calculating, or determining the parameter (or signal), or it can refer to using, selecting, or accessing a parameter (or signal) that has already been generated (e.g., by another component or device). As used herein, “coupling” can include “communication coupling,” “electrical coupling,” or “physical coupling,” and may also (or alternatively) include any combination thereof. Two devices (or components) may be coupled directly or indirectly (e.g., communication coupling, electrical coupling, or physical coupling) 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 coupled devices (or components) may be included in the same or different devices and may be connected via electronics, one or more connectors, or inductive coupling. In some implementations, two communication-coupled devices (or components) (e.g., in electrical communication) can directly or indirectly (e.g., via one or more wires, buses, networks, etc.) send and receive electrical signals (digital or analog signals). As used herein, "direct coupling" is used to describe two devices coupled (e.g., communication coupling, electrical coupling, or physical coupling) without intermediate components.

[0038] Figure 1A block diagram of an aircraft 100 is depicted. The aircraft includes a body 102 (e.g., fuselage, wings, tail, etc.), multiple landing gears 104 coupled to the body 102, an engine 106 coupled to the body 102 to provide power to the aircraft 100, one or more fuel tanks 108 configured to contain fuel for the engine 106, a computer system 110 within the body 102, and a sensor system 112 configured to provide data to the computer system 110. Specific features of the aircraft 100 are described in... Figure 1 The annotations are provided. It should be understood that aircraft 100 includes many additional features common to private, commercial, or military aircraft (e.g., communication systems, control surfaces, airflow sensors, navigation sensors, etc.), even if these features are not explicitly stated in the annotations. Figure 1 The aircraft 100 can be piloted by one or more pilots on board, can be remotely controlled by one or more pilots, and can be an autonomous aircraft or a combination thereof. The aircraft 100 can be a fixed-wing craft, a rotary-wing craft, or a hybrid-powered aircraft.

[0039] When the aircraft 100 is not in flight, the landing gear 104 supports the aircraft 100 on the ground. In some embodiments, the landing gear 104 includes a nose landing gear, a right main landing gear, and a left main landing gear. Each landing gear 104 includes a shock absorber strut 114, which is coupled to the fuselage 102 via a first support structure 116 and to a second support structure 118 (e.g., wheels, axles, supports, brakes, etc.), which is in contact with the ground when the aircraft 100 is not in flight.

[0040] Each damping strut 114 is an oil strut, which includes an outer cylinder 120 and an inner cylinder 122, the inner cylinder 122 being partially positioned within the outer cylinder 120 to allow the outer cylinder 120 to move relative to the inner cylinder 122 along the longitudinal axis of the damping strut 114. Figure 1 The inner cylinder 122 depicted includes a portion shown in dashed lines to indicate that this portion is located inside the outer cylinder 120. The torsion link 124 of the damping strut 114 is pivotally coupled to the outer cylinder 120, the inner cylinder 122, and each other to prevent the outer cylinder 120 from rotating relative to the inner cylinder 122, while allowing the outer cylinder 120 to move toward or away from the inner cylinder 122.

[0041] Each damping strut 114 includes a gas (e.g., nitrogen) and a fluid (e.g., hydraulic fluid) within an internal chamber formed by an outer cylinder 120 and an inner cylinder 122. In some embodiments, one or more separators are positioned between the gas and fluid (e.g., to suppress fluid bubbling). Each damping strut 114 includes a bearing (e.g., a DU bearing having a porous bronze interlayer impregnated with a fluoropolymer, resulting in reduced friction and increased wear resistance) to allow the outer cylinder 120 to move relative to the inner cylinder 122. The bearings include a first bearing coupled to the inner cylinder 122 near its end, positioned within the outer cylinder 120, and a second bearing coupled to the outer cylinder 120 near its end (where the inner cylinder 122 enters the outer cylinder 120). Multiple seals near the second bearing retain the fluid and gas within the damping strut 114. The movement of the outer cylinder 120 of the shock absorber strut 114 relative to the inner cylinder 122 forces fluid through the orifice plate and alters the fluid level and air pressure within the internal chamber. As described herein, the outer cylinder 120 is coupled to a first support structure 116, and the inner cylinder 122 is coupled to a second support structure 118. In other embodiments, the outer cylinder 120 is coupled to the second support structure 118, and the inner cylinder 122 is coupled to the first support structure 116.

[0042] One or more excitation devices 126 are coupled to each damper strut 114. The excitation devices 126(s) for the damper strut 114 are coupled to the outer surface of the outer cylinder 120 of the damper strut 114. The outer surface includes a mount for each excitation device 126, which allows the excitation device 126 to be attached to the outer cylinder 120 (e.g., threaded onto a shaft). The excitation device 126 can be any type of device configured to provide vibration to the outer cylinder 120. In some embodiments, the excitation device 126 is an electromagnetic vibrator, a piezoelectric actuator, or a combination thereof.

[0043] The excitation device 126 is activated by a first signal received from one or more resonant systems 128. The one or more resonant systems 128 may be line-replaceable units (LRUs) 130 of the computer system 110. Each resonant system 128 includes a controller 132 to generate a second signal with a specific frequency at a specific amplitude and duration (e.g., 1s, 3s, 5s, or some other time amount) in response to an activation signal received from one or more flight computers 134 of the computer system 110. The activation signal may be provided from the one or more flight computers 134 in response to user input (e.g., input from a loading supervisor or ground crew), or may be automatically generated in response to the flight computers 134 determining that one or more rules (e.g., completion of a loading / unloading cycle) are met.

[0044] A second signal is provided to amplifier 136, which maintains the same frequency and duration but increases the power of the second signal as an input to the first signal provided as input to one or more excitation devices 126 coupled to the resonant system 128, causing vibration of the one or more excitation devices 126 and the damping strut 114. The gain of the amplifier can be 2, 5, 10, or some other gain. In some embodiments, amplifier 136 causes the power of the first signal to increase over the entire duration of the first signal. The one or more frequencies included in the first signal, the duration of the first signal, and the gain and power distribution applied by amplifier 136 can be determined experimentally based on the response of one or more representative damping struts 114 (e.g., representative damping struts 114 of the nose landing gear 104 and representative damping struts 114 of the main landing gear 104 of a particular type of aircraft 100), and can be determined experimentally for each aircraft 100 during the manufacture of aircraft 100 or after replacement of one or more landing gears 104, or a combination thereof.

[0045] For each damping strut 114 that includes more than one excitation device 126, the resonant system 128 of the damping strut 114 includes a synchronizer 138 coupled to an amplifier 136 to adjust the phase of a first signal provided to the excitation device 126, thereby controlling the amount of disturbance generated by vibration in the outer cylinder 120 caused by the excitation device 126. Figure 1 Synchronizers 138 of the resonant system(s) 128 depicted are shown in dashed lines to indicate that synchronizers 138 for a particular resonant system 128 are optional and may not be present in embodiments that include a single excitation device 126 attached to a damping strut 114 coupled to the particular resonant system 128.

[0046] In some embodiments, the aircraft 100 includes a resonant system 128 for each damping strut 114. In other embodiments, the aircraft includes a single resonant system 128 for all damping struts 114, or the aircraft 100 includes a first resonant system 128 for one or more first damping struts 114 having a first characteristic and a second resonant system 128 for one or more damping struts 114 having a second characteristic. For example, a first damping strut 114 coupled to the first resonant system 128 is a component of the nose landing gear 104, and a second damping strut 114 coupled to the second resonant system 128 is a component of the main landing gear 104, resonating at a different frequency than the damping strut 114 of the nose landing gear 104. When the second resonant system 128 provides a first signal to the excitation device 126 associated with the two damping struts 114 of the main landing gear 104, the resonant system 128 includes a splitter 140 coupled to an amplifier 136 and a controller 132. When the controller 132 determines that the first damping strut 114 has transitioned to a dynamic state during the provision of the first signal to the first damping strut 114, the controller sends a signal to the splitter 140 to stop providing the first signal to the first damping strut 114. Figure 1 The shunt 140 of the resonant system(s) 128 depicted in the figure is shown in dashed lines to indicate that the shunt 140 for a particular resonant system 128 is optional and may not be present for an embodiment in which a particular resonant system 128 is coupled to one or more excitation devices 126 attached to only one damping strut 114.

[0047] When the aircraft 100 is on the ground, the gas in each shock absorber strut 114 supports a portion of the weight of the aircraft 100. The load on the shock absorber strut 114 in a static state is equal to the first force (i.e., air pressure multiplied by the surface area of ​​the shock absorber strut 114 to which the force is applied). A The vertical ground load of the landing gear 104 includes the vertical component of the load on the shock absorber strut 114 plus the weight of the inner cylinder 122, the weight of the fluid in the internal chamber, and the weight of the second support structure 118.

[0048] Computer system 110 includes one or more flight computers 134 (e.g., a primary flight computer and one or more standby flight computers), auxiliary computers, and LRUs 130 communicatively coupled to the one or more flight computers 134 via a data bus. Each of the one or more flight computers 134 includes one or more processors 142 and memory 144. Memory 144 includes instructions 146 and data 148 used and generated by the one or more processors 142. Instructions 146 include a plurality of flight systems 150 associated with the operation of aircraft 100, configured to facilitate the operation and use of aircraft 100 and weight and balance unit 152. Data 148 includes information used during the execution of instructions 146 by the one or more processors 142 and outputs generated by the one or more processors 142 during the execution of instructions 146. Data 148 is stored in a data structure in memory 144.

[0049] The weight and balance unit 152 obtains the weight and balance of the aircraft 100 and provides a first output associated with the weight and balance to an output device. The first output may include the total weight of the aircraft 100, the zero-fuel weight of the aircraft 100 (i.e., total weight minus fuel weight), the position of the center of gravity of the aircraft 100, warnings associated with the weight of the aircraft 100, warnings associated with the center of gravity of the aircraft 100, other information, or combinations thereof. The output device includes one or more display devices 154 of the aircraft 100 (e.g., flight displays and one or more displays located in a personnel-accessible cargo hold of the aircraft 100 associated with loading / unloading of the aircraft 100), one or more flight computers 134, one or more external devices 156 (e.g., portable devices associated with a loading supervisor), audio devices, haptic devices, other types of output devices, or combinations thereof.

[0050] In some embodiments, the weight and balance unit 152 is an onboard weight and balance system that determines the weight and balance of the aircraft 100 based on data received from sensor system 112 and (one or more) resonant systems 128, as well as first information associated with the aircraft 100 stored in data 148. In other embodiments, the weight and balance unit 152 receives data from sensor system 112 and information from (one or more) resonant systems 128, processes the data and information into inputs for an offboard weight and balance system, sends the inputs to an offboard weight and balance system (e.g., one of external devices 156) to determine the weight and balance of the aircraft based on the inputs and the first information associated with the aircraft 100, and receives an output from the offboard weight and balance system indicating the weight and balance of the aircraft 100.

[0051] The first information used to determine the weight and balance of the aircraft 100 includes parameters associated with the aircraft 100 (e.g., rake angles of the shock absorber struts 114, and the force-applied surface area of ​​each shock absorber strut 114 used to determine the first force acting on the shock absorber struts 114). A The information includes: a correction factor for the damping strut 114 used to compensate for frictional forces acting on it at the dynamic-static transition point; the weight of the fluid in the inner cylinder 122 and the damping strut 114; the weight of the second support structure 118; the axial distance from the reference point to the effective contact area between the landing gear 104 and the ground for each landing gear 104 based on the coordinate system; the average aerodynamic chord associated with the wing of the aircraft 100; the longitudinal distance from the reference point to the leading edge of the average aerodynamic chord; and other information or combinations thereof. The first information is stored in data 148, a memory associated with the off-board weight and balance system, or both.

[0052] Sensor system 112 provides sensor data from the sensors to computer system 110 for storage and use by flight computer(s) 134 and LRU 130. Sensor data includes pressure data from pressure sensor 158, temperature data from temperature sensor 160, azimuth data from one or more orientation sensors 162, and attitude data (e.g., roll and pitch angles) from the outputs of one or more attitude sensors 164 associated with the aircraft 100. Computer system 110 includes one or more data filters for the sensor data, which reduce fluctuations present in the sensor data. Each shock absorber strut 114 includes one or more pressure sensors 158 and one or more temperature sensors 160, the pressure sensors 158 being configured to measure air pressure within the shock absorber strut 114, and the temperature sensors 160 being used to measure the gas temperature within the shock absorber strut 114.

[0053] One or more orientation sensors 162 are coupled to each shock absorber strut 114 to provide sensor data used to determine whether the shock absorber strut 114 is in a dynamic or static state, whether a dynamic state results in gas compression of the shock absorber strut, or both. The orientation sensors 162 may include an angle detector for detecting the angle between torsion links 124, an orientation sensor for detecting the distance between a first point on a first torsion link and a second point on a second torsion link, an optical sensor for reading an indicia on the inner cylinder 122 indicating the orientation of the outer cylinder 120 relative to the inner cylinder 122, one or more optical sensors indicating the exposed chrome height of the inner cylinder 122, other types of sensors, or combinations thereof. Comparison of historical data from the orientation sensors 162 with current data from the orientation sensors 162 can also be used to evaluate the operational health of the shock absorber strut 114.

[0054] One or more attitude sensors 164 may be part of the inertial navigation system of the aircraft 100, or may be a separate system. When the aircraft 100 is on the ground, the attitude sensors 164 indicate the pitch angle and roll angle of the aircraft 100. In determining the weight and balance of the aircraft 100, an onboard weight and balance system or an offboard weight and balance system uses appropriate trigonometric relationships to compensate for the pitch angle, roll angle, or both.

[0055] During the use of the aircraft 100, the weight and balance unit 152 is used to obtain the weight and balance of the aircraft 100 by: calculating the weight and balance when the weight and balance unit 152 is an onboard weight and balance system; and by receiving an output indicating the weight and balance when the weight and balance of the aircraft 100 is determined by an offboard weight and balance system. The weight of the aircraft 100 is indicated as the total weight. At a specific time after activating one or more resonant systems 128 to vibrate the damping strut 114 to cause the damping strut 114 to transition from a first static state to a dynamic state and from a dynamic state to a second static state, the total weight of the aircraft 100 is determined using the following equation: in GW It is the total weight of the aircraft 100. i It is the index of landing gear 104 of aircraft 100. n It refers to the number of landing gear units, 104. F V,i It's landing gear. i Vertical force on the ground.

[0056] The balance of aircraft 100 (expressed as the CG of aircraft 100 relative to one or more axes of a three-dimensional Cartesian coordinate system, where the reference point is located at the origin of the coordinate system) is based on the moment of the vertical forces on landing gear 104 relative to the reference point and the total weight of aircraft 100. For aircraft, CG calculations are typically performed only along the longitudinal axis of the coordinate system. The longitudinal axis is aligned with the fore-and-aft direction of aircraft 100 and is orthogonal to the vertical axis (i.e., the altitude axis) passing through the reference point and the center of the Earth. For other aircraft 100 (e.g., helicopters) and some aircraft, CG calculations are performed along the longitudinal axis and the left and right axes of the coordinate system orthogonal to the longitudinal and vertical axes. When the shock absorber strut 114 is in a static state, the equation for the center of gravity of aircraft 100 relative to the reference point along the longitudinal axis of aircraft 100 is: in CG long It is the center of gravity of the aircraft 100 relative to a reference point along the longitudinal axis at a specific time. d long,i It is along the longitudinal axis from the landing gear i The distance from the effective contact point on the ground to the reference point, and This is the pitch angle of the aircraft 100. For an aircraft 100 having two main landing gears 104 and one nose landing gear 104 at a certain distance from the reference point, the longitudinal CG at a specific time is: in, d M It is the distance along the longitudinal axis from the reference point to the effective contact point of the main landing gear on the ground. F N It is the vertical force on the front landing gear. d N It is the distance along the longitudinal axis from the reference point to the effective contact point of the nose landing gear on the ground, and CG height It is the height center of gravity of the aircraft 100 relative to the ground along its vertical axis.

[0057] In some implementations, the longitudinal CG is expressed as a percentage of the average aerodynamic chord of the aircraft 100. The percentage of the average aerodynamic chord is determined by the following equation: in CG (% MAC () is the percentage of the mean aerodynamic chord. LeMAC It is the distance along the longitudinal axis from the leading edge of the mean aerodynamic chord to the reference point, and MACIt is the mean aerodynamic chord.

[0058] For the implementation method of determining left-right balance, the center of gravity of the aircraft 100 relative to a reference point is determined with respect to the left-right axis of the aircraft 100 using the following equation: in It is the center of gravity of the aircraft 100 relative to the reference point along the left and right axes. It is along the left and right axis from the landing gear i The distance from the effective contact point on the ground to the reference point, and φ It is the roll angle of the aircraft at 100.

[0059] The vertical force on one of the landing gear 104 is the vertical force applied to the shock absorber strut 114 of the landing gear 104 plus the weight of the landing gear 104 not supported by the gas in the shock absorber strut 114 (e.g., the inner cylinder 122 of the shock absorber strut 114, the fluid in the shock absorber strut 114, wheels, tires, axles, supports, brakes, etc.). When the shock absorber strut 114 of the landing gear 104 is in a static state, the vertical force on a particular landing gear 104 on the ground is determined using the following equation: Where L is the vertical load on the shock absorber strut 114 of a specific landing gear 104, which is gas-supported in the shock absorber strut 114, and M UN The weight of a specific landing gear 104 that is not gas-supported by the shock-absorbing strut 114 is determined based on parameters associated with the aircraft 100.

[0060] The vertical load on the shock absorber strut 114 is the load on the shock absorber strut 114 adjusted relative to the angle of the shock absorber strut 114 with respect to the ground. When the shock absorber strut 114 is extended, the shock absorber strut 114 has a rake angle relative to the axis perpendicular to the longitudinal axis of the aircraft 100, which is the rake angle of the shock absorber strut 114. γ When the aircraft 100 is on the ground, it has a pitch angle θ relative to the ground. The vertical load on the shock absorber strut 114 is given by the following equation: in F S It is the load (force) on the shock absorber strut 114.

[0061] The load on the damping strut 114 when it is at the dynamic-to-static transition point is given by the following equation: in P It is the air pressure in the shock absorber strut 114. A It is the surface area of ​​the shock-absorbing strut 14 where the force is applied. P·A It is the first force acting on the shock absorber strut, and F F It is the frictional force at the dynamic-to-static transition point. When the first force is less than the load, the frictional force at the dynamic-to-static transition point is compressive friction, or when the first force is greater than the load, the frictional force at the dynamic-to-static transition point is expansive friction.

[0062] Analysis of sensor data (e.g., orientation sensor data, pressure sensor data, or both) determines whether the damper strut 114 is at a dynamic-to-static transition point, and whether the frictional force at this transition point is compressive or expansive. For example, analysis of the sensor data indicates that the outer cylinder 120 of the damper strut is moving towards the inner cylinder 122 of the damper strut 114, or that the air pressure data indicates an increase in air pressure, or both. This indicates that the damper strut 114 is in a dynamic state, and the frictional force at the dynamic-to-static transition point will be compressive friction. Conversely, a dynamic-to-static transition is indicated when the orientation data indicates that the outer cylinder 120 has stopped moving relative to the inner cylinder 122, or when the air pressure has stopped changing, or both. When the frictional force is either compressive or expansive, the load on the damper strut 114 at the dynamic-to-static transition point is given by the following equation: in, It is the magnitude of the compressive friction force, and It is the magnitude of the expansion friction force.

[0063] The magnitudes of the frictional forces (compressive and expansive friction) at the dynamic-static transition point are modeled as a shift from the first force by a correction factor, which is represented by the following equation: in c It is a correction factor. Substituting the frictional force from equation (11) into equation (9) and the factored result into equation (7), the following equation is provided to determine the vertical load on the damping strut 114 at the dynamic-static transition when the frictional force is compressive friction: Similarly, substituting the frictional force from equation (11) into equation (9), and substituting the result of factorization into equation (8), provides the following equation for determining the vertical load on the damping strut 114 at the dynamic-static transition when the frictional force is expansive friction: When the aircraft 100 lands, it taxis to a position (e.g., a gate or parking position). Upon arrival at this position, one or more flight computers 134 can activate the weight and balance unit 152 to determine the weight and balance of the aircraft 100 without using the resonant system 128. The resonant system 128 is not required because the shock absorber struts 114 are at or near the dynamic-static transition, and the friction force of each shock absorber strut 114 is compressive friction.

[0064] The weight and balance unit 152 updates the first data structure with data for each shock absorber strut 114. The first data structure includes information for each shock absorber strut 114, which can be used by the weight and balance system to determine the weight and balance of the aircraft. The information in the first data structure includes, for each shock absorber strut, the latest dynamic-static transition pressure entry and friction type entry for the shock absorber strut 114 without activating the excitation device(s) 126 coupled to the shock absorber strut 114; and, after the activation cycle of the resonant system(s) 128, warning indicators, gas temperature entries, pressure entries, and friction type entries for each shock absorber strut. The weight and balance unit 152 updates the entries in the first data structure for each shock absorber strut 114 (which correspond to the latest dynamic-static transition pressure entry without activating the excitation device(s) 126, and the latest dynamic-static transition friction type entry (whose value corresponds to compressive friction)).

[0065] The aircraft 100 undergoes loading / unloading cycles (e.g., passenger and crew disembarkation and boarding, cargo and baggage loading and unloading, waste removal, refueling, food and beverage resupply, etc.). During the loading / unloading cycle, the weight and balance unit monitors sensor data from the shock absorber struts 114 to determine the occurrence of a dynamic-to-static transition, the air pressure of the shock absorber struts 114 undergoing the dynamic-to-static transition at the transition point, and the type of friction force of the shock absorber struts 114 undergoing the dynamic-to-static transition. The weight and balance unit updates the corresponding entries in the first data structure for the shock absorber struts 114 undergoing the dynamic-to-static transition during the loading / unloading cycle.

[0066] After the loading / unloading cycle is completed, flight computer(s)134 receives input to begin determining the weight and balance of aircraft 100. This input may be user input from a loading supervisor or ground crew associated with aircraft 100, or it may be automatic input in response to a part of computer system 110 determining that the aircraft is in a ready-to-depart condition. In response to this input, weight and balance unit 152 sends an activation signal to resonant system(s)128.

[0067] For each resonant system 128 coupled to only one specific damping strut 114, the activation signal causes the controller 132 of the resonant system 128 to set a counter to zero; set the values ​​of the gas temperature entry, the gas pressure entry, and the friction type indicator in the data structure for the resonant system 128 to zero; and set the warning indicator for the specific damping strut 114 to logical true in the data structure. The counter increments by 1 each time the first signal sent to one or more excitation devices 126 attached to the specific damping strut 114 does not cause one or more excitation devices 126 to transition the specific damping strut 114 to a dynamic state.

[0068] Controller 132 generates a second signal with one or more frequencies at a specific amplitude and a first duration, and sends the second signal and a counter to amplifier 136. The first duration is based on the counter value. For example, when the counter is 0, the total duration of the second signal is 5 seconds (evenly distributed among the frequencies included in the signal), and the total duration of the second signal increases by 5 seconds for each increment of the counter. As another example, the total duration of the second signal is 5 seconds when the counter is 0 or 1, and the total duration of the second signal increases by 5 seconds when the counter is 2. Other total durations, other duration variations, or no change in duration may also be implemented.

[0069] Amplifier 136 generates a first signal having one or more frequencies and a first duration, but increases power based on the value of a counter, and provides the first signal to one or more excitation devices 126 associated with a specific damping strut 114. For example, when the counter is 0, the power of the first signal is increased to twice its original value; when the counter is 1, the power of the first signal is increased to 2.5 times its original value; and when the counter is 2, the power of the first signal is increased to 2.75 times its original value. Other modes of increasing power may also be implemented.

[0070] During the provision of a first signal to a specific damping strut 114, controller 132 analyzes sensor data associated with the specific damping strut 114 to determine whether the specific damping strut 114 has transitioned to a dynamic state. For example, controller 132 analyzes orientation data from one or more orientation sensors 162 associated with the specific damping strut 114 to determine the change in the orientation of the outer cylinder 120 relative to the inner cylinder 122 of the specific damping strut at the current time relative to the orientation of the outer cylinder 120 relative to the inner cylinder 122 before the first signal was provided to one or more excitation devices 126 attached to the specific damping strut 114, and analyzes air pressure data of the specific damping strut 114 to determine the change in air pressure of the specific damping strut 114 at the current time relative to the air pressure of the specific damping strut 114 before the first signal was provided to one or more excitation devices 126 attached to the specific damping strut 114. When the change in orientation meets a first threshold (e.g., the change in orientation is greater than 0.1 inches), the change in air pressure meets a second threshold (e.g., the change in air pressure is greater than 50 psi), or both, the controller 132 determines that a particular shock absorber strut 114 transitions to a dynamic state.

[0071] In response to providing a first signal to a specific damping strut 114, the resonant system 128 performs one or more iterations of the following procedure. Each time the specific damping strut 114 does not transition to a dynamic state during the provision of the first signal to one or more excitation devices 126 of the specific damping strut 114, the controller 132 increments a counter by 1. When the counter value is less than a threshold (e.g., 3, 4, or some other number), a new second signal with one or more frequencies and durations is generated based on the counter, and the second signal is provided to the amplifier 136 for amplification based on the counter value. The amplifier 136 provides the first signal to the specific damping strut 114 and determines whether the first signal causes the specific damping strut 114 to transition to a dynamic state. If the specific damping strut 114 does not undergo a transition to a dynamic state in response to the activation of the first signal by one or more excitation devices 126, the procedure is repeated. If a specific damping strut 114 transitions to a dynamic state while providing a first signal to one or more excitation devices 126, the controller 132 causes the amplifier 136 to stop providing the first signal to the specific damping strut 114; determines the type of friction force (e.g., compression or expansion) associated with the specific damping strut 114 at the dynamic-to-static transition; changes the type of the friction indicator based on the type (e.g., 1 for compression static friction and 2 for expansion static friction); determines the gas temperature of the specific damping strut 114 and sets the value of the gas temperature entry to that gas temperature; determines the gas pressure of the specific damping strut 114 at the dynamic-to-static transition and sets the value of the gas pressure entry to that gas pressure; changes the warning indicator to logical false; and sends this data structure as input to the weight and balance unit 152. If the counter equals a threshold, the controller 132 determines the gas temperature of the specific damping strut 114 and sets the gas temperature entry to that gas temperature; determines the gas pressure of the specific damping strut 114 and sets the gas pressure entry to that gas pressure; and sends this data structure as input to the weight and balance unit 152.

[0072] For each resonant system 128 coupled to two or more damping struts 114, the activation signal causes the controller 132 of the resonant system 128 to set a counter to zero, set the friction type indicator in the data structure of the resonant system 128 for each of the two or more damping struts 114 to 0, set the warning indicator for each of the two or more damping struts 114 to logical true in the data structure, and set the gas temperature and pressure entries in the data structure for each of the two or more damping struts 114 to 0. The counter increments by 1 when one or more of the damping struts 114 coupled to the resonant system 128 fails to transition to a dynamic state in response to one or more first signals provided to the excitation devices 126 attached to the two or more damping struts 114.

[0073] The controller 132 of the resonant system 128 generates a second signal with one or more frequencies at a specific amplitude and a first duration, and sends the second signal and a counter to the amplifier 136. The first duration may be based on the counter value. The amplifier 136 generates a first signal with one or more frequencies and the same first duration as the second signal, but increases the power based on the counter value. The amplifier 136 provides the first signal to one or more excitation devices 126 associated with two or more damping struts 114.

[0074] During the provision of a first signal to a damping strut 114 coupled to the resonant system 128 (dampening strut 114 does not transition to a dynamic state based on vibration caused by the first signal), controller 132 analyzes sensor data to determine whether one or more of the damping struts 114 that did not previously transition to a dynamic state due to the provision of one or more first signals to one or more excitation devices coupled to one or more damping struts 114 will transition to a dynamic state due to the current application of one or more first signals to one or more excitation devices coupled to the one or more damping struts 114. For example, for each of one or more shock absorber struts 114, controller 132 determines the change in the orientation of the outer cylinder 120 of the shock absorber strut 114 relative to the inner cylinder 122 relative to the orientation of the outer cylinder 120 of the shock absorber strut 114 relative to the orientation of the inner cylinder 122 of the shock absorber strut 114 before providing one or more first signals to the one or more excitation devices 126 attached to the shock absorber strut 114, and determines the change in the air pressure of the shock absorber strut 114 at the current time relative to the air pressure of the shock absorber strut 114 before providing the first signal to the one or more excitation devices 126 attached to the shock absorber strut 114. When the change in orientation satisfies a first threshold, the change in air pressure satisfies a second threshold, or both, controller 132 determines that the shock absorber strut 114 transitions to a dynamic state.

[0075] In response to providing one or more first signals to one or more damping struts 114 associated with the resonant system 128, the resonant system 128 performs one or more iterations of the following procedure. When one or more damping struts 114 transition to a dynamic state, the controller includes logic that stops transmitting one or more first signals to the one or more damping struts 114 transitioning to the dynamic state and stops sending additional one or more first signals generated after incrementing a counter to the one or more damping struts 114 transitioning to the dynamic state; determines the friction type of each damping strut 114 transitioning to the dynamic state at the dynamic-static transition; sets the warning indicator of each damping strut 114 transitioning to the dynamic state to logic false; and sets the friction indicator in a data structure to a value corresponding to the friction type at the dynamic-static transition for each damping strut 114 transitioning to the dynamic state; determines the gas temperature and pressure of each damping strut 114 at the dynamic-static transition for the one or more damping struts 114 transitioning to the dynamic state due to the first signal; and stores these values ​​in the corresponding gas temperature and pressure entries. If all warning indicators of the damping struts 114 associated with the resonant system 128 in the data structure have logical false values, the controller 132 sends the data structure as input to the weight and balancing unit 152. If the data structure includes warning indicators with logical true values, the controller 132 includes logic that increments a counter by 1, and if the counter is less than a threshold, causes the amplifier 136 to generate a new first signal and send it to one or more excitation devices 126 attached to one or more damping struts 114 with warning indicators (which have logical true values), and repeats this procedure. If the counter is at the threshold, the controller 132 determines the gas temperature and pressure of each damping strut (where the warning indicator is logical true) and stores these values ​​in the corresponding gas temperature and pressure entries, and sends the data structure as input to the weight and balancing unit 152.

[0076] When the weight and balance unit 152 receives input from one or more resonant systems 128 in response to one or more activation signals sent to the resonant systems 128, the weight and balance unit 152 updates the first data structure with the corresponding entries of the input received from the resonant systems 128 and obtains the weight and balance of the aircraft 100. When the weight and balance system is an onboard weight and balance unit 152, the weight and balance unit determines the weight and balance of the aircraft 100, and when the weight and balance system is an offboard weight and balance system, the weight and balance unit 152 sends the first data structure to the offboard weight and balance system.

[0077] The weight and balance system (i.e., the weight and balance unit 152 when it is an onboard weight and balance system; or a non-onboard weight and balance system) analyzes a first data structure to determine whether any warning indicators associated with the shock absorber strut 114 are logically true. If one or more warning indicators are logically true, the weight and balance system determines the type of friction associated with each shock absorber strut 114 having a warning indicator that is logically true. This type is determined based on the type associated with another shock absorber strut 114, the type of the shock absorber strut 114 prior to the use of one or more excitation devices 126 attached to the shock absorber strut 114 having a warning indicator that is true, or both. For example, if the first shock absorber strut 114 of the right main landing gear 104 has a warning indicator that is logically true, and the left main landing gear 102 has a warning indicator that is logically false, the weight and balance system changes the value of the friction type of the shock absorber strut 114 of the right main landing gear 104 to a value corresponding to the friction type of the shock absorber strut 114 of the left main landing gear 104. As another example, if all shock absorber struts 114 have warning indicators that are logically true, the weight and balance system changes the friction type of each shock absorber strut 114 to a value corresponding to the type of the most recent dynamic-static transition prior to the activation of the excitation device 126. The weight and balance system includes several rules for handling different cases when one or more warning indicators of one or more shock absorber struts 114 are logically true. This could include changing one or more friction type indicators to values ​​corresponding to compressive friction or static friction when determining the weight and balance of the aircraft, or leaving one or more friction type indicators unchanged to indicate that the correction factor associated with the corresponding shock absorber strut is not used.

[0078] After using rules to process any warning indicators as logically true, the weight and balance system determines the weight and balance of the aircraft 100 based on the appropriate entries in the first data structure and the parameters associated with the aircraft 100. For each landing gear 104, when the friction type indicator of the shock absorber strut 114 in the first data structure indicates compressive friction, the vertical load on the shock absorber strut 114 is determined using equation (12) with an appropriate correction factor; when the friction type indicator of the shock absorber strut 114 in the first data structure indicates expansive friction, the vertical load on the shock absorber strut 114 is determined using equation (13) with an appropriate correction factor; and when the friction type indicator of the shock absorber strut 114 in the first data structure does not indicate compressive or expansive friction, the vertical load on the shock absorber strut 114 is determined using equation (12) or (13) with a correction value of 0. In some embodiments, when the gas temperature of the damping strut 114 in the first data structure is within a specific temperature range, an appropriate correction factor for the damping strut 114 may be a first value (e.g., 0.025); when the gas temperature of the damping strut 114 in the first data structure is above the specific temperature range, an appropriate correction factor for the damping strut 114 may be a second value (e.g., 0.023); and when the gas temperature of the damping strut 114 in the first data structure is below the specific temperature range, an appropriate correction factor for the damping strut 114 may be a third value (e.g., 0.027). In other embodiments, an appropriate correction factor is determined based on one or more correction factor values ​​retrieved from a correction factor table based on the gas temperature of the damping strut 114 in the first data structure.

[0079] The vertical load on the ground for each landing gear 104 is determined using equation (6), which uses the appropriate vertical load of the shock absorber struts 114 of the landing gear 104. The weight of the aircraft 100 is then determined using equation (1), and one or more CGs are determined using one or more of equations (2)-(5). If the weight and balance system is an off-board weight and balance system, the weight and balance system sends its output back to the weight and balance unit 152, which includes the weight of the aircraft 100 and the determined CG as the balance of the aircraft 100.

[0080] The weight and balance unit 152 provides a first output to one or more flight computers 134, indicating the weight and balance of the aircraft 100. The first output includes the weight of the aircraft 100, the balance of the aircraft 100 (as one or more CGs), and logical truth values ​​associated with each shock absorber strut 114 having a logically true warning indicator in a first data structure. The flight computers generate information based on the first output to one or more output devices (e.g., one or more display devices 154, one or more external devices 156 associated with the loading supervisor, warnings to audio or haptic devices, etc.).

[0081] The weight and balance unit 152 stores historical data about warning indicators that are true. If a warning indicator for a particular damping strut 114 is logically true for a threshold number of consecutive load / unload cycles (e.g., 5, 6, or some other number of consecutive load cycles), the weight and balance unit 152 causes the scheduling of maintenance for the resonant system 128 and excitation device(s) 126 associated with the particular damping strut.

[0082] Figure 2 A side view depicting a portion of an embodiment of an aircraft 100 on ground 202. Figure 2 The ground 202 depicted is horizontal relative to a Earth-based coordinate system having a first axis 204; a second axis orthogonal to the first axis 204; and a third axis orthogonal to the first axis 204, the second axis, and passing through the Earth's center. In other cases, the ground 202 may form a non-zero angle relative to the first axis 204, the second axis, or both. The aircraft 100 includes a longitudinal axis 206, which is the longitudinal axis of the aircraft 100 relative to its coordinate system, and a pitch angle... θ It is the angle between the first axis 204 and the front and rear axes 206.

[0083] The friction surfaces of the shock absorber strut 114 of the nose landing gear 104A (e.g., a portion of the outer surface of the inner cylinder 122, a portion of the inner surface of the outer cylinder 120, and the contact surface of the bearing) have a first tilt angle γ relative to the aircraft coordinate system (e.g., the perpendicular 208A relative to the front and rear axes 206). A .exist Figure 2 In this embodiment, the right main landing gear 104B and the left main landing gear are each offset by the same longitudinal distance from a reference point, and by the same left-right distance from the first axis 204. Each friction surface of the right main landing gear 104B and the left main landing gear forms a second tilt angle γ relative to the aircraft coordinate system (e.g., the perpendicular 208B relative to the front-rear axis 206). B Tilt angle γ A γ BThe values ​​of the offset distance are part of the landing gear configuration of the aircraft 100 and are stored in data 148 of memory 144, memory of the off-board weight and balance system, or both. These values ​​are used by the weight and balance system (e.g., weight and balance unit 152 when it is an on-board weight and balance system) to obtain the weight and CG of the aircraft 100. In some embodiments, the tilt angle γ A γ B One or both of them are zero.

[0084] Figure 2 The computer system 110 and weight and balance unit 152 depicted are shown in dashed lines to indicate that the computer system 110 and weight and balance unit are not visible from the outside of the aircraft 100. During the execution of the weight and balance unit 152, the computer system 110 obtains the weight and balance of the aircraft 100 by performing calculations or by receiving weight and balance in response to inputs provided to the off-board weight and balance system by the weight and balance unit 152. An excitation device 126 is coupled to the shock absorber struts 114 of the landing gear 104A, 104B. The excitation device is configured to vibrate the shock absorber struts 114 in response to signals received from the computer system 110. The excitation device 126 is electrically coupled to the computer system 110 via wiring (not shown) or wirelessly.

[0085] Figure 3 A flowchart depicts an implementation of method 300, which uses the aircraft's computer system to cause vibration damping struts to release a portion of the static friction acting on the struts before determining the aircraft's weight and balance. Method 300 can be derived from... Figure 1 The computer system 110 of the aircraft 100 depicted in the figure is executed. Method 300 utilizes one or more flight computers 134 and one or more resonant systems 128.

[0086] At block 302, method 300 includes receiving a request to determine the weight of the aircraft at the aircraft's computer system. The aircraft includes a plurality of landing gears, and each of the plurality of landing gears includes a shock absorber strut. One or more excitation devices are coupled to each shock absorber strut. The one or more excitation devices coupled to a particular shock absorber strut are configured to vibrate the particular shock absorber strut to enable the particular shock absorber strut to transition from a first static state to a dynamic state and from a dynamic state to a second static state, in which the outer cylinder of the particular shock absorber strut is stationary relative to the inner cylinder of the particular shock absorber strut, and in the dynamic state, the outer cylinder moves relative to the inner cylinder. For example, after a loading / unloading cycle of the aircraft 100 is completed, the aircraft 100's computer system 110 receives user input from a loading supervisor or ground crew, or the computer system determines that the loading / unloading cycle has been completed, and in response to the user input, the determination that the loading / unloading cycle has been completed, or both, the computer system 110 sends a request to determine the aircraft weight and balance to one or more flight computers 134.

[0087] At block 304, method 300 includes, in response to the request, causing one or more resonant systems via a computer system to send a first signal to an excitation device to activate the excitation device to vibrate the damping strut. For example, one or more processors 142 of flight computer(s) 134 execute weight and balance unit 152 to send an activation signal to each of the one or more resonant systems 128. In response to the activation signal(s), the one or more resonant systems perform one or more iterations by generating the first signal and providing it to the excitation device 126 of the damping strut 114 attached to the landing gear 104 of the aircraft, up to a threshold number of iterations.

[0088] The controller 132 of each resonant system 128 processes sensor data (e.g., temperature data, pressure data, and positioning data) associated with the damping struts 114 coupled to the resonant system 128 to determine whether the damping struts 114 have transitioned from a static state to a dynamic state in response to vibrations supplied to the damping struts 114 by one or more excitation devices 126 attached to the damping struts 114. If all damping struts coupled to the resonant system 128 have transitioned to a dynamic state or a threshold number of iterations has been exceeded, the controller provides input data to the weight and balancing unit 152 based on the sensor data associated with the damping struts 114.

[0089] At block 306, method 300 includes obtaining aircraft weight and balance at a computer system based on input received from one or more resonant systems. For example, in response to one or more activation signals sent to resonant system(s) 128, processor(s) 142 of flight computer(s) 134 updates values ​​in a first data structure for execution of weight and balance unit 152 based on input received from resonant system(s) 128. Execution of weight and balance unit 152 causes weight and balance unit 152 to obtain aircraft weight and balance either by calculating aircraft weight and balance or by receiving aircraft weight and balance in response to sending the first data structure to an off-board weight and balance system.

[0090] Furthermore, at block 308, method 300 includes providing a first output based on aircraft weight and balance from a computer system to one or more output devices. For example, execution of weight and balance unit 152 by processor 142 of flight computer 134 causes weight and balance unit 152 to provide information on aircraft weight and balance, as well as information identifying any landing gear 104 of shock absorber 114 that has not transitioned to a dynamic state in response to vibrations caused by excitation devices 126 attached to shock absorber 114, to flight system 150 executed by processor 142 of flight computer 134. Flight system 150 automatically provides output to one or more output devices (e.g., display device 154, external device 156, audio device, haptic device, or other device) in response to user input or in response to the satisfaction of one or more conditions.

[0091] Figure 4 This is a flowchart illustrating a method 400 for representing the lifecycle of an aircraft 100, which includes... Figure 1 The depicted aircraft includes a computer system 110 and a shock absorber strut 114 with attached excitation devices 126. During pre-production, the exemplary method 400 includes the specifications and design of the aircraft 100 at block 402. During the specification and design of the aircraft 100, method 400 may include the specifications and design of the resonant system 128, the weight and balance unit 152 of the flight computer(s) 134, predictions of parameter values ​​associated with the aircraft 100 (which are subsequently used by the computer system 110), the specifications of the shock absorber strut 114 and the excitation mount of the shock absorber strut 114, and the specifications of the excitation devices 126(s) of each shock absorber strut 114. These parameters include the tilt angle of the extended landing gear 104 and the applied force surface area of ​​each shock absorber strut 114. AThe parameters include the weight of each landing gear 104 not supported by the gas-operated shock-absorbing strut 114 associated with the landing gear 104, and the axial distance from the reference point to the effective ground contact position of the landing gear 104 relative to the reference point relative to the coordinate system. After the aircraft 100 is manufactured, the values ​​of these parameters can be adjusted to correspond to the actual values.

[0092] At box 404, method 400 includes material procurement, which may include procuring computer system 110 and other components of aircraft 100. During production, method 400 includes component and sub-assembly manufacturing at box 406 and system integration of aircraft 100 at box 408.

[0093] At box 410, method 400 includes the certification and delivery of aircraft 100, and at box 412, putting aircraft 100 into service. Certification and delivery may include the certification of computer system 110 to put aircraft 100 into service. At box 414, method 400 includes performing maintenance and servicing on aircraft 100, which may include modification, reconfiguration, refurbishment, replacement, etc., of one or more systems of aircraft 100. Maintenance and servicing of computer system 110 may include updating correction factors based on a comparison of calculated weight with the actual weight from a calibration scale where aircraft 100 is located.

[0094] Each process of Method 400 may be performed or implemented by a systems integrator, a third party, and / or an operator (e.g., a customer). For the purposes of this description, a systems integrator may include, but is not limited to, any number of aircraft manufacturers and main system subcontractors; a third party may include, but is not limited to, any number of suppliers, subcontractors, and vendors; and an operator may be an airline, leasing company, military entity, service organization, etc.

[0095] Figure 5 This is an illustration of a block diagram of a computing environment 500, which includes a computing device 502 configured to support implementations of computer-implemented methods and computer-executable program instructions (or code) according to this disclosure. For example, the computing device 502 or a portion thereof may execute instructions to perform or cause the device to perform reference. Figures 1-4 The operation described. In the implementation, computing device 502 is aircraft 100, computer system 110, (one or more) resonant system 128, LRU 130, controller 132, (one or more) flight computer 134, amplifier 136, synchronizer 138 and splitter, or components thereof.

[0096] Computing device 502 includes one or more processors 504. Processor 504 communicates with system memory 506, one or more storage devices 508, one or more input / output interfaces 510, one or more communication interfaces 512, or combinations thereof. System memory 506 includes non-transitory computer-readable media, including volatile memory devices (e.g., random access memory (RAM) devices), non-volatile memory devices (e.g., read-only memory (ROM) devices, programmable read-only memory, and flash memory), or both. System memory 506 includes an operating system 514, which may include a basic input / output system for booting computing device 502 and a complete operating system enabling computing device 502 to interact with users, other programs, and other devices. System memory 506 includes one or more application programs 516 (e.g., instructions) executable by processor 504. For example, when computing device 502 is a flight computer 134, one or more application programs 516 include flight system 150 and weight and balance unit 152.

[0097] In some configurations, processor 504 communicates with one or more storage devices 508. For example, storage device 508 includes non-transitory computer-readable media, which may include non-volatile storage devices such as disks, optical discs, or flash memory devices. Storage device 508 may include removable and non-removable memory devices. Storage device 508 may be configured to store an operating system, an image of the operating system, application programs, and program data. In certain embodiments, system memory 506, storage device 508, or both include tangible computer-readable media incorporated into the hardware, and these media are not signals.

[0098] In some configurations, processor 504 communicates with one or more input / output interfaces 510, which enable computing device 502 to communicate with one or more input / output devices 518 (e.g., display devices 154) to facilitate user interaction. Input / output interfaces 510 may include serial interfaces (e.g., Universal Serial Bus (USB) interfaces or Institute of Electrical and Electronics Engineers (IEEE) interfaces), parallel interfaces, display adapters, audio adapters, and other interfaces (“IEEE” is a registered trademark of Institute of Electrical and Electronics Engineers, Inc., Piscataway, New Jersey). Input / output devices 518 may include keyboards, pointing devices, displays (e.g., one or more monitors, one or more meters, etc.), speakers, microphones, touchscreens, rotatable selectors, joysticks, knobs, sliders, switches, and other devices. Processor 504 detects interactive events based on user input received via input / output interfaces 510. Additionally, processor 504 sends displays to display devices via input / output interfaces 510.

[0099] In some configurations, processor 504 may communicate with one or more devices 520 via one or more communication interfaces 512. The one or more devices 520 may include external computing devices contacted via a communication network and controllers, sensors, and other devices coupled to computing device 502 via wired or wireless local connections. For example, when computing device 502 is part of computer system 110, computing device 502 is configured to communicate with devices external to aircraft 100 (e.g., external devices 156 (e.g., portable devices)) via communication interfaces 512. The one or more communication interfaces 512 may include wired Ethernet interfaces, IEEE 802 wireless interfaces, other wireless communication interfaces, one or more converters that convert analog signals to digital signals, electrical signals to optical signals, one or more converters that convert received optical signals to electrical signals, or other network interfaces.

[0100] 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 may be executable to implement the joint provisions herein. Figures 1-5 One or more operations or methods are described. In some implementations, this document is combined with... Figures 1-5 Some or all of the described one or more operations or methods may be implemented by one or more processors executing instructions (e.g., one or more central processing units (CPUs), one or more graphics processing units (GPUs), one or more digital signal processors (DSPs), one or more application-specific integrated circuits (ASICs), etc.), special-purpose hardware circuitry systems, or both.

[0101] Specific aspects of this disclosure are described below by a set of interconnected examples: According to Example 1, a system for an aircraft includes: a landing gear damping strut; one or more excitation devices coupled to the damping strut, wherein the one or more excitation devices are configured to vibrate the damping strut to enable the damping strut to transition from a first static state to a dynamic state and from the dynamic state to a second static state, in the first static state, an outer cylinder of the damping strut being stationary relative to an inner cylinder of the damping strut, and in the dynamic state, the outer cylinder moving relative to the inner cylinder; and a resonant system coupled to the one or more excitation devices, wherein the resonant system is configured to provide a signal to the one or more excitation devices to activate the one or more excitation devices to vibrate the damping strut.

[0102] Example 2 includes a system according to Example 1, wherein the resonant system includes a controller, an amplifier, a synchronizer, or a combination thereof.

[0103] Example 3 includes the system according to Example 1 or Example 2, and further includes one or more orientation sensors coupled to the shock absorber strut, wherein the one or more orientation sensors are configured to determine the travel of the inner cylinder relative to the outer cylinder.

[0104] Example 4 includes a system according to any one of Examples 1 to 3, wherein the excitation device in the one or more excitation devices includes an electromagnetic vibrator, a piezoelectric actuator, or both.

[0105] Example 5 includes the system according to any one of Examples 1 to 4, and further includes one or more pressure sensors coupled to the shock absorber strut, wherein the one or more pressure sensors are configured to measure air pressure in the shock absorber strut.

[0106] Example 6 includes the system according to Example 5, and further includes a computer system configured to determine the vertical ground load of the landing gear, the weight of the aircraft, the center of gravity of the aircraft, or a combination thereof, based on the output of the one or more pressure sensors after the one or more excitation devices are activated.

[0107] According to Example 7, an aircraft includes: a plurality of landing gears, each of the plurality of landing gears including a shock absorber strut; one or more excitation devices coupled to each shock absorber strut, wherein the one or more excitation devices coupled to a particular shock absorber strut are configured to vibrate the particular shock absorber strut to enable the particular shock absorber strut to transition from a first static state to a dynamic state and from the dynamic state to a second static state, in the first static state, an outer cylinder of the particular shock absorber strut being stationary relative to an inner cylinder of the particular shock absorber strut, and in the dynamic state, the outer cylinder being movable relative to the inner cylinder; and one or more resonant systems coupled to the excitation devices, wherein the one or more resonant systems are configured to provide a first signal to the excitation devices to activate the excitation devices to vibrate the shock absorber strut.

[0108] Example 8 includes the aircraft described in Example 7, and further includes one or more controllers, one or more amplifiers, or both, configured to provide a first signal to each of the one or more excitation devices.

[0109] Example 9 includes an aircraft according to Example 8, wherein the particular shock absorber strut is a component of the nose landing gear, and wherein the one or more controllers include a first controller configured to provide the first signal to each of the one or more excitation devices coupled to the particular shock absorber strut.

[0110] Example 10 includes an aircraft according to Example 8, wherein the particular shock absorber strut is a component of a first main landing gear, and wherein the one or more controllers include a second controller configured to provide the first signal to each of the one or more excitation devices coupled to the particular shock absorber strut.

[0111] Example 11 includes an aircraft according to Example 10, wherein the second controller is further configured to provide the first signal to one or more second excitation devices coupled to the second shock absorber strut, and wherein the second shock absorber strut is a component of the second main landing gear.

[0112] Example 12 includes an aircraft according to any one of Examples 7 to 11, and further includes a plurality of pressure sensors coupled to the shock absorber strut, wherein each of the plurality of pressure sensors is configured to measure air pressure in the corresponding shock absorber strut.

[0113] Example 13 includes the aircraft according to Example 12, and further includes a computer system configured to determine the vertical ground load of each landing gear based on the output of the one or more pressure sensors, and wherein the computer system is also configured to determine the weight of the aircraft, the center of gravity of the aircraft, or both, based on the vertical ground load.

[0114] According to Example 14, a method includes: receiving a request at a computer system of an aircraft to determine the weight of the aircraft, wherein the aircraft includes a plurality of landing gears, and each of the plurality of landing gears includes a shock absorber strut, wherein one or more excitation devices are coupled to each shock absorber strut, and wherein the one or more excitation devices coupled to a particular shock absorber strut are configured to vibrate the particular shock absorber strut to enable the particular shock absorber strut to transition from the first static state to the dynamic state and from the dynamic state to the second static state, wherein in the first static state the outer cylinder of the particular shock absorber strut is stationary relative to the inner cylinder of the particular shock absorber strut, and in the dynamic state the outer cylinder moves relative to the inner cylinder; and in response to the request, causing one or more resonant systems via the computer system to send a first signal to the excitation devices to vibrate the shock absorber strut.

[0115] Example 15 includes the method according to Example 14, and further includes: determining at the computer system a change in the orientation of the outer cylinder of the first shock absorber relative to the inner cylinder of the first shock absorber caused by vibration of the first shock absorber in response to a first signal sent to one or more excitation devices in the excitation device, wherein the orientation of the outer cylinder relative to the inner cylinder before and after the first shock absorber vibrates in response to the first signal for a first time period is determined based on the outputs of one or more orientation sensors coupled to the first shock absorber; and determining, via the computer system, a vertical ground load of a first landing gear including the first shock absorber, based on the outputs of one or more pressure sensors coupled to the first shock absorber to measure air pressure in the first shock absorber in response to the change in orientation satisfying a first threshold.

[0116] Example 16 includes the method according to Example 15, and further includes: in response to the change in orientation not satisfying the first threshold, and in response to a second determination that the iterative cycle count of the resonant systems coupled to the first damping strut in the one or more resonant systems satisfies the threshold: generating a new first signal via the computer system; providing the new first signal to the one or more excitation devices via the computer system for a longer second time period to vibrate the first damping strut; and in response to determining that a second change in the orientation of the outer cylinder relative to the inner cylinder satisfies the first threshold, determining the vertical ground load of the first landing gear via the computer system based on the output of the one or more pressure sensors.

[0117] Example 17 includes the method according to Example 16, wherein the second time period is longer than the first time period, wherein the power of the new first signal is greater than the power of the first signal, or both.

[0118] Example 18 includes the method according to any one of Examples 15 to 18, and further includes: in response to a change in orientation not satisfying a first threshold, and in response to determining that the activation cycle number of the one or more excitation devices does not satisfy a second threshold: determining the vertical ground load of the first landing gear via the computer system based on the output of the one or more pressure sensors; and generating an alarm based on the vertical ground load of the landing gear that is associated with the weight of the aircraft, the center of gravity of the aircraft, or both.

[0119] Example 19 includes a method according to any one of Examples 14 to 18, wherein one or more pressure sensors are coupled to each shock absorber strut to measure air pressure in each shock absorber strut, and further includes: after providing the first signal, determining, via the computer system, a vertical ground load of each landing gear based on the output of the one or more pressure sensors; and determining, via the computer system, the weight of the aircraft, the center of gravity of the aircraft, or both, based on the vertical ground load of each landing gear.

[0120] Example 20 includes the method according to any one of Examples 14 to 19, wherein a first weight of the aircraft is determined after the aircraft has come to a stop following taxiing to a gate or parking position.

[0121] The illustrations in this document are intended to provide a general understanding of the structure of various embodiments. These illustrations 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 embodiments may be apparent to those skilled in the art upon review of this disclosure. Other embodiments may be utilized and derived from this disclosure, allowing for structural and logical substitutions and variations without departing from the scope of this disclosure. For example, method operations may be performed in a different order than those shown in the drawings, or one or more method operations may be omitted. Therefore, this disclosure and the drawings should be considered illustrative rather than restrictive.

[0122] Furthermore, although specific examples have been shown and described herein, it should be understood that any subsequent arrangements designed to achieve the same or similar results may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all subsequent adaptations or variations of the various embodiments. In retrospect, combinations of the above embodiments and other embodiments not specifically described herein will be apparent to those skilled in the art.

[0123] The abstract of this disclosure is intended not to be construed as limiting 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 embodiment for the purpose of simplifying 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 cover fewer features than any of the disclosed examples. Therefore, the scope of this disclosure is defined by the appended claims and their equivalents.

[0124] In addition, this application also includes embodiments according to the following terms.

[0125] Clause 1. A system for an aircraft 200, said system comprising: Shock absorber strut 114 of landing gear 104; One or more excitation devices 126 coupled to the damping strut, wherein the one or more excitation devices are configured to vibrate the damping strut to enable the damping strut to transition from a first static state to a dynamic state and from the dynamic state to a second static state, in the first static state in which the outer cylinder 120 of the damping strut is stationary relative to the inner cylinder 122 of the damping strut, and in the dynamic state in which the outer cylinder moves relative to the inner cylinder; and A resonant system 128 is coupled to the one or more excitation devices, wherein the resonant system is configured to provide a signal to the one or more excitation devices to activate the one or more excitation devices.

[0126] Clause 2. The system according to Clause 1, wherein the resonant system includes a controller 132, an amplifier 136, a synchronizer 138, or a combination thereof.

[0127] Clause 3. The system according to Clause 1 further includes one or more orientation sensors 162 coupled to the shock absorber strut, wherein the one or more orientation sensors are configured to determine the travel of the inner cylinder relative to the outer cylinder.

[0128] Clause 4. The system according to Clause 1, wherein the excitation device in the one or more excitation devices includes an electromagnetic vibrator, a piezoelectric actuator, or both.

[0129] Clause 5. The system according to Clause 1 further includes one or more pressure sensors 158 coupled to the shock absorber strut, wherein the one or more pressure sensors are configured to measure air pressure in the shock absorber strut.

[0130] Clause 6. The system according to Clause 5 further includes a computer system 110 configured to determine the vertical ground load of the landing gear, the weight of the aircraft, the center of gravity of the aircraft, or a combination thereof, based on the output of the one or more pressure sensors after activation of the one or more excitation devices.

[0131] Clause 7. An aircraft 100 comprising: Multiple landing gears 104, wherein each of the multiple landing gears includes a shock-absorbing strut 114; One or more excitation devices 126 coupled to each damper strut, wherein the one or more excitation devices coupled to a particular damper strut are configured to vibrate the particular damper strut to enable the particular damper strut to transition from a first static state to a dynamic state and from the dynamic state to a second static state, in which the outer cylinder 120 of the particular damper strut is stationary relative to the inner cylinder 122 of the particular damper strut, and in the dynamic state, the outer cylinder moves relative to the inner cylinder; and One or more resonant systems 128 are coupled to the excitation device, wherein the one or more resonant systems are configured to provide a first signal to the excitation device to activate the excitation device.

[0132] Clause 8. The aircraft pursuant to Clause 7 further includes one or more controllers 132, one or more amplifiers 136, or both, configured to provide a first signal to each of the one or more excitation devices.

[0133] Clause 9. The aircraft as described in Clause 8, wherein the particular shock absorber strut is a component of the nose landing gear, and wherein the one or more controllers include a first controller configured to provide the first signal to each of the one or more excitation devices coupled to the particular shock absorber strut.

[0134] Clause 10. The aircraft as described in Clause 8, wherein the particular shock absorber strut is a component of the first main landing gear, and wherein the one or more controllers include a second controller configured to provide the first signal to each of the one or more excitation devices coupled to the particular shock absorber strut.

[0135] Clause 11. The aircraft according to Clause 10, wherein the second controller is further configured to provide the first signal to one or more second excitation devices coupled to the second shock absorber strut, and wherein the second shock absorber strut is a component of the second main landing gear.

[0136] Clause 12. The aircraft according to Clause 7 further includes a plurality of pressure sensors 158 coupled to the shock absorber strut, wherein each of the plurality of pressure sensors is configured to measure air pressure in the corresponding shock absorber strut.

[0137] Clause 13. The aircraft according to Clause 12 further includes a computer system 110, wherein the computer system is configured to determine the vertical ground load of each landing gear based on the output of the one or more pressure sensors, and wherein the computer system is also configured to determine the weight of the aircraft, the center of gravity of the aircraft, or both, based on the vertical ground load.

[0138] Clause 14. A method 300, comprising: A request to determine the weight of the aircraft is received at the computer system 110 of the aircraft 100, wherein the aircraft includes a plurality of landing gears 104, and each of the plurality of landing gears includes a shock absorber strut 114, wherein one or more excitation devices 126 are coupled to each shock absorber strut, and wherein the one or more excitation devices coupled to a particular shock absorber strut are configured to vibrate the particular shock absorber strut to enable the particular shock absorber strut to transition from a first static state to a dynamic state and from the dynamic state to a second static state, in which the outer cylinder of the particular shock absorber strut is stationary relative to the inner cylinder of the particular shock absorber strut, and in the dynamic state, the outer cylinder moves relative to the inner cylinder; and In response to the request, the computer system causes one or more resonant systems 128 to send a first signal to the excitation device to vibrate the damping strut.

[0139] Clause 15. The method described pursuant to Clause 14 further includes: The computer system determines the change in orientation of the outer cylinder 120 of the first damping strut relative to the inner cylinder 122 of the first damping strut due to vibration of the first damping strut in response to a first signal sent to one or more excitation devices in the excitation device, wherein the orientation of the outer cylinder relative to the inner cylinder before and after the first damping strut vibrates in response to the first signal for a first time period is determined based on the output of one or more orientation sensors 162 coupled to the first damping strut; and In response to a change in orientation satisfying a first threshold, the computer system determines the vertical ground load of the first landing gear, including the first shock absorber, based on the output of one or more pressure sensors coupled to the first shock absorber strut to measure air pressure in the first shock absorber strut.

[0140] Clause 16. The method according to Clause 15 further comprises, in response to a change in orientation not satisfying the first threshold, and in response to a second determination that the iterative cycle count of the resonant systems coupled to the first damping strut in the one or more resonant systems satisfies the threshold: A new first signal is generated via the computer system; The computer system provides the new first signal to the one or more excitation devices for a second time period to vibrate the first damping strut; and In response to determining that a second change in the orientation of the outer cylinder relative to the inner cylinder satisfies the first threshold, the vertical ground load of the first landing gear is determined by the computer system based on the output of the one or more pressure sensors.

[0141] Clause 17. The method according to Clause 16, wherein the second time period is longer than the first time period, wherein the power of the new first signal is greater than the power of the first signal, or both.

[0142] Clause 18. The method according to Clause 15 further includes, in response to a change in orientation not satisfying the first threshold, and in response to determining that the activation cycle number of the one or more excitation devices has not satisfied a second threshold: Based on the outputs of the one or more pressure sensors, the vertical ground load of the first landing gear is determined via the computer system; and An alarm is generated based on the vertical ground load of the landing gear and is associated with the weight of the aircraft, the center of gravity of the aircraft, or both.

[0143] Clause 19. The method according to Clause 14, wherein one or more pressure sensors are coupled to each shock absorber strut to measure the air pressure in each shock absorber strut, and the method further comprises: After providing the first signal, the vertical ground load of each landing gear is determined via the computer system based on the outputs of the one or more pressure sensors; and The weight of the aircraft, the center of gravity of the aircraft, or both, are determined via the computer system based on the vertical ground load of each landing gear.

[0144] Clause 20. The method according to Clause 14, wherein the first weight of the aircraft is determined after the aircraft has come to a stop following taxiing to the gate or parking position.

Claims

1. A system for an aircraft (200), the system comprising: Shock-absorbing struts (114) for landing gear (104); One or more excitation devices (126) coupled to the damping strut, wherein the one or more excitation devices are configured to vibrate the damping strut to enable the damping strut to transition from a first static state to a dynamic state and from the dynamic state to a second static state, in the first static state in which the outer cylinder (120) of the damping strut is stationary relative to the inner cylinder (122) of the damping strut, and in the dynamic state in which the outer cylinder moves relative to the inner cylinder; and A resonant system (128) coupled to the one or more excitation devices, wherein the resonant system is configured to provide a signal to the one or more excitation devices to activate the one or more excitation devices.

2. The system according to claim 1, wherein the resonant system comprises a controller (132), an amplifier (136), a synchronizer (138), or a combination thereof.

3. The system of claim 1 further includes one or more orientation sensors (162) coupled to the shock absorber strut, wherein the one or more orientation sensors are configured to determine the travel of the inner cylinder relative to the outer cylinder.

4. The system of claim 1, wherein the excitation device in the one or more excitation devices comprises an electromagnetic vibrator, a piezoelectric actuator, or both.

5. The system of claim 1 further includes one or more pressure sensors (158) coupled to the shock absorber strut, wherein the one or more pressure sensors are configured to measure air pressure in the shock absorber strut.

6. The system of claim 5, further comprising a computer system (110) configured to determine the vertical ground load of the landing gear, the weight of the aircraft, the center of gravity of the aircraft, or a combination thereof, based on the output of the one or more pressure sensors after activation of the one or more excitation devices.

7. An aircraft (100) comprising: Multiple landing gears (104), each of the multiple landing gears including a shock-absorbing strut (114). One or more excitation devices (126) coupled to each damping strut, wherein the one or more excitation devices coupled to a particular damping strut are configured to vibrate the particular damping strut to enable the particular damping strut to transition from a first static state to a dynamic state and from the dynamic state to a second static state, in the first static state in which the outer cylinder (120) of the particular damping strut is stationary relative to the inner cylinder (122) of the particular damping strut, and in the dynamic state in which the outer cylinder moves relative to the inner cylinder; as well as One or more resonant systems (128) coupled to the excitation device, wherein the one or more resonant systems are configured to provide a first signal to the excitation device to activate the excitation device.

8. The aircraft of claim 7 further includes one or more controllers (132), one or more amplifiers (136), or both, configured to provide a first signal to each of the one or more excitation devices.

9. The aircraft of claim 8, wherein the particular shock absorber strut is a component of the nose landing gear, and wherein the one or more controllers include a first controller configured to provide the first signal to each of the one or more excitation devices coupled to the particular shock absorber strut.

10. The aircraft of claim 8, wherein the particular shock absorber strut is a component of the first main landing gear, and wherein the one or more controllers include a second controller configured to provide the first signal to each of the one or more excitation devices coupled to the particular shock absorber strut.

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