A method and system for measuring the compression of a tire of a swing arm landing gear

Abstract

This invention relates to the field of aircraft landing gear drop test measurement technology, and in particular to a method and system for measuring tire compression of rocker arm landing gear. By setting a rigid, large-area reflector at the tail end of the lower rocker arm, even with the complex motion trajectory of the tire contact point during impact, the reflector surface can always produce a stable reference reflective point under a preset light source, which can be continuously tracked by an optical sensor. Instead of tracking and measuring the instantaneous position of the tire contact point, key data directly related to the movement of the tail end of the lower rocker arm can be indirectly and reliably obtained by stably measuring the vertical displacement of this reflective point. Based on this, the invention, combined with the vertical deflection distance determined by the geometry of the rocker arm assembly, can accurately separate the pure tire compression from the measured comprehensive vertical displacement, thereby eliminating the influence of the rocker arm rotation component and the complex trajectory of the contact point on the measurement results, significantly improving the accuracy of tire compression measurement.

Description

Technical Field

[0001] This invention relates to the field of aircraft landing gear drop test measurement technology, and in particular to a method and system for measuring the tire compression of rocker-arm landing gear. Background Technology

[0002] Landing gear drop tests are a crucial verification method for assessing the landing gear's shock absorption characteristics and structural strength. By conducting simulated landing impact tests, these tests provide data support for analyzing the design and safety performance of the landing gear. The compression of the landing gear tires during drop tests is a core measurement parameter that reflects the load distribution among the various landing gear components. This is essential for analyzing the impact load transmission path and evaluating the effectiveness of the landing gear cushioning system, and is necessary data for landing gear tire selection and accurate calibration of the overall aircraft dynamics model.

[0003] However, for a rocker arm landing gear, due to its unique rocker arm structure—that is, the linkage between the rocker arm and the shock absorber—the rotational motion of the rocker arm around its hinge point and the compression deformation of the tire itself are coupled during landing impact. The superposition of these two motion trajectories makes it extremely difficult to distinguish the tire compression from the vertical displacement component driven by the rocker arm rotation from the overall vertical displacement. Furthermore, the rapid instantaneous deformation of the tire under impact load and its dynamic change in stiffness further increase measurement errors, making it difficult to accurately obtain the tire compression of the rocker arm landing gear during drop tests.

[0004] For measuring tire compression in aircraft landing gear, existing technologies have proposed various solutions, but all have certain limitations and are unsuitable for measuring tire compression in rocker-arm landing gear. For example, one publicly available image measurement method uses a calibrated high-speed camera to photograph wheel axle markers and indirectly calculates tire compression through coordinate transformation. While this method alleviates some of the errors associated with contact measurements, it relies on expensive image acquisition and processing hardware, has a cumbersome operational process, and cannot achieve real-time processing and output of measurement data, making it difficult to meet the high-efficiency and high-real-time measurement requirements of rocker-arm landing gear testing. Another technical solution uses a device with a movable measuring rod to measure the tire compression by calculating the height difference before and after compression. Although this method is simple in structure and easy to use, its measurement path is limited to the vertical direction, which cannot adapt to the complex movement trajectory of the tire contact point during impact in rocker-arm landing gear, thus limiting its applicability. In addition, some technical solutions propose using a measurement device combining linear displacement sensors and triaxial tilt sensors to achieve real-time measurement. However, this device has a relatively complex structure and requires extremely high sensor installation accuracy and calibration, increasing the complexity of test preparation and system uncertainty.

[0005] Therefore, existing tire compression measurement technologies are still insufficient to meet the comprehensive requirements of rocker-arm landing gear for high-precision, high-real-time performance, and low-cost tire compression measurement in drop tests. Summary of the Invention

[0006] The present invention aims to provide a method and system for measuring the tire compression of a rocker arm landing gear, so as to provide a convenient and accurate method for obtaining the tire compression of a rocker arm landing gear during a drop test, thereby improving the accuracy of the tire compression measurement of the rocker arm landing gear.

[0007] To achieve the above objectives, the first aspect of the present invention provides a method for measuring tire compression of a rocker-arm landing gear, applicable to rocker-arm landing gears and tires. The rocker-arm landing gear is equipped with a landing gear buffer and a rocker arm assembly. The upper intersection point of the landing gear buffer is movably connected to the upper rocker arm of the rocker arm assembly, and the lower intersection point of the landing gear buffer is movably connected to the lower rocker arm of the rocker arm assembly. The intersection point of the movably connected upper and lower rocker arms is the intersection point of the rocker arm assembly. The tail end of the lower rocker arm is movably connected to the wheel axle of the tire. The method includes the following steps: A reflector is provided at the tail end of the lower rocker arm; The lower edge of the tire is brought into critical contact with the ground, so that the reflective point of the reflector relative to the preset light source is located at the center of the wheel axle. The initial vertical distance of the reflective point relative to the light source is then obtained, and the initial state data of the rocker arm landing gear and the tire are obtained. The rocker arm landing gear and the tires are driven to perform a drop-shock motion, and the reflector rotates together with the lower rocker arm. At any moment during the drop motion, the current vertical distance of the reflective point relative to the light source is obtained, and then the current vertical displacement is calculated based on the initial vertical distance and the current vertical distance, and the current state data of the rocker arm landing gear and the tires are obtained. Based on the initial state data and the current state data, the vertical deflection distance of the reflective point is obtained, and then the current vertical displacement is subtracted from the vertical deflection distance to obtain the current tire compression, thus completing the tire compression measurement.

[0008] The aforementioned method for measuring tire compression of a rocker arm landing gear utilizes a rigid, large-area reflector at the tail end of the lower rocker arm as a rigid component that moves synchronously with the lower rocker arm. This ensures that during drop tests, even if the rocker arm landing gear experiences complex motion trajectories at the tire contact point during impact, the reflector surface will always produce a stable reference reflective point under a preset light source that can be continuously tracked by an optical sensor. This eliminates the need for the system to directly track or measure the instantaneous position of the tire contact point. Instead, it indirectly and reliably obtains key data directly related to the movement of the tail end of the lower rocker arm by stably measuring the vertical displacement of the reflective point.

[0009] Based on this, the present invention combines the vertical deflection distance determined by the geometry of the rocker arm assembly, which can accurately separate the pure tire compression from the measured comprehensive vertical displacement, thereby eliminating the influence of the rocker arm rotation component and the complex trajectory of the contact point on the measurement results, and significantly improving the accuracy of tire compression measurement.

[0010] Meanwhile, this invention achieves non-contact measurement and fast response through optical means, enabling real-time and continuous measurement of the dynamic compression process in tire drop tests.

[0011] In summary, this invention provides a tire compression measurement method that is adaptable to complex tire movements, highly accurate, and easy to implement, through a simple and easy-to-install optical measurement mechanism for rocker-arm landing gear drop tests.

[0012] Furthermore, the initial state data includes a first initial horizontal distance from the lower intersection of the landing gear buffer to the intersection of the rocker arm assembly, and a second initial horizontal distance from the center of the wheel axle to the lower intersection of the landing gear buffer; the current state data includes a first current horizontal distance from the lower intersection of the landing gear buffer to the intersection of the rocker arm assembly, and a second current horizontal distance from the center of the wheel axle to the lower intersection of the landing gear buffer. The step of obtaining the vertical deflection distance of the reflective point based on the initial state data and the current state data includes: The first horizontal displacement of the lower intersection point of the landing gear buffer relative to the intersection point of the rocker arm assembly is obtained based on the first initial horizontal distance and the first current horizontal distance. The second horizontal displacement of the center of the wheel axle relative to the lower intersection point of the landing gear buffer is obtained based on the second initial horizontal distance and the second current horizontal distance; The total horizontal displacement of the center of the wheel axle relative to the intersection point of the rocker arm assembly is obtained based on the first horizontal displacement and the second horizontal displacement. The vertical deflection distance of the reflective point is obtained based on the total horizontal displacement.

[0013] In this implementation, the complex spatial motion of the rocker arm landing gear and tires in the drop test is decomposed into key displacement components along the horizontal direction for measurement and synthesis. That is, the first horizontal displacement and the second horizontal displacement are used to characterize the local geometric changes caused by the compression of the buffer and the rotation of the rocker arm, respectively. Then, the total horizontal displacement is used to comprehensively reflect the overall horizontal motion of the wheel axle center relative to the hinge point of the rocker arm assembly.

[0014] Based on the total horizontal displacement, and according to the specific geometric configuration of the rocker arm assembly, the vertical deflection distance of the reflective point caused by the pure rotation of the rocker arm can be calculated deterministically. This avoids the difficulty of directly measuring angles or spatial coordinates, and significantly reduces the difficulty of tire compression and device requirements.

[0015] At the same time, by using this total horizontal displacement, the vertical displacement component introduced by the rocker arm rotation in the current vertical displacement can be separated, thereby subtracting the deflection distance from the current vertical displacement to obtain the pure tire compression, which improves the accuracy and reliability of the tire compression measurement and calculation results.

[0016] Further, acquiring the initial state data of the rocker arm landing gear and the tires includes: The following parameters are obtained: a first distance between the upper intersection point of the landing gear buffer and the intersection point of the rocker arm assembly; a second distance between the lower intersection point of the landing gear buffer and the intersection point of the rocker arm assembly; a third distance between the upper intersection point of the landing gear buffer and the lower intersection point of the landing gear buffer; a fourth distance between the lower intersection point of the landing gear buffer and the center of the wheel axle; a first angle between the first distance and the second distance; a second angle between the fourth distance and the direction of gravity; and a third angle between the first distance and the direction of gravity. The first initial horizontal distance is obtained based on the second distance, the first included angle, and the third included angle; the second initial horizontal distance is obtained based on the fourth distance and the second included angle. The acquisition of the current status data of the rocker arm landing gear and the tires includes: The axial displacement of the upper intersection point and the lower intersection point of the landing gear buffer is obtained, and the current distance between the upper and lower intersection points is calculated based on the axial displacement and the third distance; the change value of the first included angle is obtained based on the first distance, the second distance and the current distance between the upper and lower intersection points. The first current horizontal distance is obtained based on the second distance, the third included angle, and the change value of the first included angle; the second current horizontal distance is obtained based on the fourth distance, the second included angle, and the change value of the first included angle.

[0017] In this implementation, by acquiring and processing a series of key static geometric parameters and dynamic changes between the rocker arm landing gear components, a geometric kinematic calculation model of the rocker arm landing gear and tires is constructed. Thus, without directly measuring the complex spatial trajectory of the drop test, the intermediate variables for solving the tire compression are indirectly calculated.

[0018] Specifically, in the static initial state where the tires and the ground are in critical contact, the geometric parameters reflecting the initial configuration of the landing gear, such as the first distance, the second distance, the third distance, the fourth distance, and each key angle, are measured to provide accurate initial static data for indirectly calculating relevant dynamic variables during the subsequent drop test.

[0019] During the dynamic motion of the drop test, this invention directly measures the axial displacement of the landing gear buffer, combines it with the initial third distance of the landing gear buffer, determines the real-time change of the distance between the upper and lower intersection points of the buffer, and then calculates the change value of the first included angle based on geometric relationships such as the triangle cosine theorem; and then links the linear compression motion of the buffer with the rotational motion of the rocker arm through geometric constraints.

[0020] Subsequently, based on the dynamically changing angle value, the first current horizontal distance and the second current horizontal distance can be updated and calculated in real time. This transforms the spatial position and angle changes that are difficult to measure directly in the drop test into the measurement of the easily obtainable buffer stroke change, which significantly simplifies the measuring device and the measuring process. While possessing the accuracy of tire compression measurement, it also has good engineering practicality and reliability.

[0021] It should be noted that the landing gear damper, as the core shock-absorbing component of the rocker arm landing gear, is typically an oil-pneumatic or hydropneumatic damping strut. Its structure mainly includes an outer cylinder and an inner cylinder, or a cylinder and a piston rod, which can generate relative linear motion along the axial direction. In drop tests, when the landing gear is subjected to a vertical impact load, the damper dissipates energy through the compression and flow of its internal medium. Specifically, this is manifested in the dynamic change of the distance between its upper and lower intersection points with the load; that is, the current distance between the upper and lower intersection points changes dynamically with the load, and this change is the axial displacement.

[0022] This axial linear motion, through the hinged relationship between the upper and lower intersection points and the rocker arm assembly, directly drives the rocker arm to rotate around its assembly intersection points, thus constituting the unique coupled kinematic characteristics of the rocker arm landing gear. This invention, by accurately measuring this axial displacement and combining it with the fixed geometric dimensions of the rocker arm assembly, reversely solves for the real-time rotation angle and other derived geometric parameters of the rocker arm. This allows for the precise separation of the pure tire compression from the measured comprehensive vertical displacement, thereby eliminating the influence of the rocker arm rotation component and the complex trajectory of the contact point on the measurement results.

[0023] Further, obtaining the vertical deflection distance of the reflective point based on the total horizontal displacement includes: Based on the total horizontal displacement and the first angle change value, the vertical deflection distance of the reflective point is obtained.

[0024] It should be noted that this invention establishes a definite trigonometric relationship between the vertical deflection of the reflective point and the horizontal movement of the tail end of the lower rocker arm to which it is attached during the rotation of the rocker arm around its component intersection point. The specific form of this relationship is determined by the real-time rotation angle of the rocker arm, i.e., the change value of the first included angle. Therefore, by substituting the total horizontal displacement, which characterizes the overall horizontal position change of the wheel axle center, and the change value of the first included angle, which precisely characterizes the change of the rocker arm's own rotation angle, into the corresponding geometric relationship, the vertical deflection distance component of the reflective point caused purely by the rotation of the rocker arm can be directly calculated.

[0025] The above calculation steps avoid additional vertical measurement steps, eliminate potential independent sources of measurement error in this direction, and simplify the measurement device and calculation path. Furthermore, since both the total horizontal displacement and the change in the first included angle are intermediate results obtained from reliable measurements and geometric derivations in the aforementioned steps, the accuracy of the final vertical deflection distance value is enhanced, which is beneficial for ultimately improving the accuracy of tire compression measurement.

[0026] Furthermore, the preset light source is a laser sensor set at a preset reference point on the ground. The laser sensor emits a laser perpendicular to the ground, so that the reflective point of the reflector relative to the laser is located at the center of the wheel axle. Then, the initial vertical distance of the reflective point relative to the laser sensor is obtained through the laser sensor, or the current vertical distance of the reflective point relative to the laser sensor is obtained through the laser sensor.

[0027] In this implementation, by fixing the origin and direction of the measurement coordinate system to a ground reference point unaffected by the movement of the test piece, and defining a clear vertical measurement axis using a vertical laser beam, the laser sensor can quickly and non-contactly acquire the precise distance of the reflective point relative to itself. Simultaneously, by initially adjusting the laser spot to coincide with the wheel axle center, a direct geometric correspondence is established between the reflective point, the wheel axle center, and the ground reference point in the vertical direction. This provides accurate static baseline data for subsequently correlating the measured vertical displacement with the spatial motion changes at the tail end of the lower rocker arm, thus providing a reliable and efficient core data acquisition method for the entire tire compression measurement method, improving the accuracy and response speed of tire compression measurement.

[0028] Furthermore, obtaining the axial displacement of the upper intersection point and the lower intersection point of the landing gear buffer includes: arranging a wire-type displacement sensor in the axial direction of the landing gear buffer; The axial displacement of the upper intersection point and the lower intersection point of the landing gear buffer is obtained by the pull-wire displacement sensor.

[0029] In this implementation, a wire-type displacement sensor is directly installed along the axial direction of the landing gear buffer to obtain the axial displacement between its upper and lower intersection points. The wire-type displacement sensor features good linearity, strong resistance to shock vibration, and flexible installation, making it suitable for measurement environments with severe, instantaneous impacts, such as drop tests. This wire-type displacement sensor can directly capture the linear compression or elongation displacement of the buffer under impact loads, and is easily recorded and processed synchronously by the data acquisition system.

[0030] This implementation avoids the cumulative errors that may be introduced by complex spatial coordinate back calculations or indirect derivations. At the same time, the installation of this sensor usually does not require complex modifications to the landing gear buffer body, making installation simple and having minimal impact on the mechanical properties of the test piece itself. Thus, while ensuring measurement accuracy, it significantly improves the practicality and reliability of the entire measurement system.

[0031] A second aspect of the present invention provides a rocker arm landing gear tire compression measurement system, applicable to rocker arm landing gears and tires. The rocker arm landing gear includes a landing gear buffer and a rocker arm assembly. The upper intersection point of the landing gear buffer is movably connected to the upper rocker arm of the rocker arm assembly, and the lower intersection point of the landing gear buffer is movably connected to the lower rocker arm of the rocker arm assembly. The intersection point of the movably connected upper and lower rocker arms is the intersection point of the rocker arm assembly. The tail end of the lower rocker arm is movably connected to the tire axle. The measurement system includes: A reflector is set at the tail end of the lower rocker arm, a laser sensor is set at a preset reference point on the ground, and a wire-type displacement sensor is set along the axial direction of the landing gear buffer, wherein the laser sensor emits a laser perpendicular to the ground. The initial data measurement module is used to bring the lower edge of the tire to a critical contact state with the ground, so that the reflective point of the reflector relative to the laser is located at the center of the wheel axle. Then, the laser sensor obtains the initial vertical distance of the reflective point relative to the light source, and obtains the initial state data of the rocker arm landing gear and the tire. The drop test module is used to drive the rocker arm landing gear and the tire to perform drop test movements, and to make the reflector rotate together with the lower rocker arm; The current data measurement module is used to obtain the current vertical distance of the reflective point relative to the light source at any moment during the drop motion through the laser sensor, and then calculate the current vertical displacement based on the initial vertical distance and the current vertical distance, and obtain the current state data of the rocker arm landing gear and the tire through the pull-wire displacement sensor. The tire compression calculation module is used to obtain the vertical deflection distance of the reflective point based on the initial state data and the current state data, and then subtract the vertical deflection distance from the current vertical displacement to obtain the current tire compression, thus completing the tire compression measurement.

[0032] Furthermore, the initial state data includes a first initial horizontal distance from the lower intersection of the landing gear buffer to the intersection of the rocker arm assembly, and a second initial horizontal distance from the center of the wheel axle to the lower intersection of the landing gear buffer; the current state data includes a first current horizontal distance from the lower intersection of the landing gear buffer to the intersection of the rocker arm assembly, and a second current horizontal distance from the center of the wheel axle to the lower intersection of the landing gear buffer. The step of obtaining the vertical deflection distance of the reflective point based on the initial state data and the current state data includes: The first horizontal displacement of the lower intersection point of the landing gear buffer relative to the intersection point of the rocker arm assembly is obtained based on the first initial horizontal distance and the first current horizontal distance. The second horizontal displacement of the center of the wheel axle relative to the lower intersection point of the landing gear buffer is obtained based on the second initial horizontal distance and the second current horizontal distance; The total horizontal displacement of the center of the wheel axle relative to the intersection point of the rocker arm assembly is obtained based on the first horizontal displacement and the second horizontal displacement. The vertical deflection distance of the reflective point is obtained based on the total horizontal displacement.

[0033] Further, acquiring the initial state data of the rocker arm landing gear and the tires includes: The following parameters are obtained: a first distance between the upper intersection point of the landing gear buffer and the intersection point of the rocker arm assembly; a second distance between the lower intersection point of the landing gear buffer and the intersection point of the rocker arm assembly; a third distance between the upper intersection point of the landing gear buffer and the lower intersection point of the landing gear buffer; a fourth distance between the lower intersection point of the landing gear buffer and the center of the wheel axle; a first angle between the first distance and the second distance; a second angle between the fourth distance and the direction of gravity; and a third angle between the first distance and the direction of gravity. The first initial horizontal distance is obtained based on the second distance, the first included angle, and the third included angle; the second initial horizontal distance is obtained based on the fourth distance and the second included angle. The acquisition of current status data of the rocker arm landing gear and the tires via the wire-type displacement sensor includes: The axial displacement of the upper intersection point and the lower intersection point of the landing gear buffer are obtained by the pull-wire displacement sensor, and the current distance between the upper and lower intersection points is calculated based on the axial displacement and the third distance; the change value of the first included angle is obtained based on the first distance, the second distance and the current distance between the upper and lower intersection points. The first current horizontal distance is obtained based on the second distance, the third included angle, and the change value of the first included angle; the second current horizontal distance is obtained based on the fourth distance, the second included angle, and the change value of the first included angle.

[0034] Further, obtaining the vertical deflection distance of the reflective point based on the total horizontal displacement includes: Based on the total horizontal displacement and the first angle change value, the vertical deflection distance of the reflective point is obtained. Attached Figure Description

[0035] Figure 1 This is a flowchart illustrating a method for measuring tire compression of a rocker-arm landing gear according to an embodiment of the present invention. Figure 2 This is a schematic diagram comparing the critical contact of a tire with the ground and the compression state of a tire, provided by an embodiment of the present invention. Figure 3 This is a schematic diagram of the wire-type displacement sensor, laser sensor, and reflective point position structure provided in the embodiments of the present invention; Figure 4 This is a schematic diagram of the first principle of the rocker arm landing gear tire compression measurement method provided in this embodiment of the invention; Figure 5 This is a schematic diagram of the second principle of the rocker arm landing gear tire compression measurement method provided in this embodiment of the invention; Figure 6 This is a schematic diagram of the tire compression change curve during the entire drop test measured according to an embodiment of the present invention; Figure 7 This is a schematic diagram of a rocker arm landing gear tire compression measurement system provided in an embodiment of the present invention; The components include: 1. Landing gear buffer; 2. Tire; 3. Axle; 4. Reflector; 5. Ground; 6. Rocker arm assembly; 7. Wire-type displacement sensor; 8. Reflector point; 9. Laser sensor. Detailed Implementation

[0036] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that the following detailed descriptions are exemplary and intended to provide further detailed explanation of the invention. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein in the specification is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings, are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings are used to distinguish different objects, not to describe a particular order.

[0037] It should be understood that although the steps in the flowcharts of the accompanying figures are shown sequentially as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the accompanying figures may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the sub-steps or stages of other steps.

[0038] Before describing this application in detail with reference to the accompanying drawings and embodiments, the terms and application scenarios involved in this application will first be explained.

[0039] Drop tests simulate landing impact conditions to verify the core performance of the landing gear, including its shock absorption, energy dissipation, and structural strength. The results provide crucial support for design optimization and safety certification. Tire compression, as a core measurement parameter in the test, directly affects the transmission of impact loads and the effectiveness of the cushioning system. Its data reflects the load distribution pattern, helps avoid the risks of overload or insufficient energy absorption, and provides key input for wheel selection and dynamic model calibration. It is an essential step in ensuring the effectiveness of the test and the reliability of the landing gear design.

[0040] Due to the structural characteristics of the rocker arm and the shock absorber being linked, measuring tire compression in rocker-arm landing gear presents significant challenges. During landing impact, the rotation of the rocker arm around the hinge point is coupled with the tire compression deformation, and the motion trajectories of the two are superimposed, making it difficult to directly distinguish between the pure tire compression and the displacement driven by the rocker arm. At the same time, the rapid instantaneous deformation and dynamic changes in stiffness of the tire under impact load further exacerbate measurement errors, making it difficult to accurately obtain tire compression data.

[0041] In the relevant technical field, an image measurement method for tire compression and axle displacement in a drop test has been disclosed. The method involves capturing axle markers with a calibrated high-speed camera, obtaining the axle position through coordinate transformation, and then calculating the compression. Although this method alleviates the error problem of traditional measurement, it suffers from high hardware investment costs, cumbersome operation procedures, and the inability to achieve real-time output of measurement data. It is still difficult to meet the high-efficiency and accurate measurement requirements of rocker-arm landing gear.

[0042] In addition, a measuring device and method for measuring the compression of aircraft tires have been disclosed in the related technical field. The tire compression is measured by calculating the height difference before and after tire compression using a measuring device with a movable measuring rod. Although the method is simple to calculate and easy to use, it is not suitable for measuring the compression of rocker arm landing gear tires because it can only move in the vertical direction.

[0043] In addition, a device and method for measuring the compression of aircraft tires has been proposed in the related technical field. It uses a linear displacement sensor and a triaxial tilt sensor. Although it can measure the compression of tires in real time, the device is complex and requires high installation accuracy.

[0044] With the development of aircraft, in order to achieve higher measurement standards for rocker arm landing gear drop tests and meet the requirements for accurate real-time dynamic measurement of tire compression, this invention proposes a dynamic measurement method that is simple to install and highly practical.

[0045] Please refer to Figure 1 and Figure 2 To achieve the above objectives, the first aspect of the present invention provides a method for measuring the tire compression of a rocker-arm landing gear, applicable to rocker-arm landing gear and tire 2. The rocker-arm landing gear is provided with a landing gear buffer 1 and a rocker arm assembly 6. The upper intersection point of the landing gear buffer 1 is movably connected to the upper rocker arm of the rocker arm assembly 6, and the lower intersection point of the landing gear buffer 1 is movably connected to the lower rocker arm of the rocker arm assembly 6. The intersection point of the movably connected upper and lower rocker arms is the intersection point of the rocker arm assembly 6. The tail end of the lower rocker arm is movably connected to the wheel axle 3 of the tire 2. The method includes the following steps: S1. A reflector 4 is installed at the tail end of the lower rocker arm.

[0046] S2. Make the lower edge of the tire 2 be in critical contact with the ground 5, so that the reflector 4 and the reflective point 8 of the preset light source are located at the center of the wheel axle 3, and then obtain the initial vertical distance of the reflective point 8 relative to the light source, and obtain the initial state data of the rocker arm landing gear and the tire 2.

[0047] For details, please refer to Figure 2 , Figure 2This diagram illustrates a comparison between a tire's critical contact with the ground and its compression state. As shown in the diagram, in the initial static stage, when tire 2 is critically in contact with the ground, the distance between the center of wheel axle 3 and the ground is equal to the tire radius. During the drop motion, the tire is compressed by the ground, and the distance between wheel axle 3 and the ground changes. The difference in height between this change and the initial static stage represents the current tire compression. .

[0048] S3. Drive the rocker arm landing gear and the tire 2 to perform a drop vibration movement, and make the reflector 4 rotate together with the lower rocker arm.

[0049] S4. At any moment during the drop motion, obtain the current vertical distance of the reflector point 8 relative to the light source, and then calculate the current vertical displacement based on the initial vertical distance and the current vertical distance. And obtain the current status data of the rocker arm landing gear and the tire 2.

[0050] S5. Obtain the vertical deflection distance of the reflective point 8 based on the initial state data and the current state data. This will further reduce the current vertical displacement. Subtract the vertical deflection distance To obtain the current tire compression Complete the tire compression measurement.

[0051] The aforementioned method for measuring tire compression of a rocker arm landing gear, by setting a rigid, large-area reflector 4 at the tail end of the lower rocker arm as a rigid component that moves synchronously with the lower rocker arm, ensures that during the drop test, even if the rocker arm landing gear experiences a complex motion trajectory at the tire 2 contact point during the impact, the surface of the reflector 4 can always generate a stable reference reflective point 8 under a preset light source, which can be continuously tracked by an optical sensor. This allows the system to obtain key data directly related to the movement of the tail end of the lower rocker arm indirectly and reliably by measuring the vertical displacement of the reflective point 8, without directly tracking or measuring the instantaneous position of the tire 2 contact point.

[0052] Based on this, the present invention incorporates the vertical deflection distance determined by the geometry of the rocker arm assembly 6. It can accurately separate the pure tire compression from the measured comprehensive vertical displacement, thereby eliminating the influence of the rocker arm rotation component and the complex trajectory of the contact point on the measurement results, and significantly improving the accuracy of tire compression measurement.

[0053] Meanwhile, this invention achieves non-contact measurement and fast response through optical means, enabling real-time and continuous measurement of the dynamic compression process in tire drop tests.

[0054] In summary, this invention provides a tire compression measurement method that is adaptable to the complex movements of the tire 2, highly accurate, and easy to implement, through a simple and easy-to-install optical measurement mechanism.

[0055] Further, please refer to Figure 5 , Figure 5 In the diagram, A1 is the upper intersection point of landing gear buffer 1, A2 is the lower intersection point of landing gear buffer 1, B is the intersection point of the rocker arm assembly, and C is the center position of wheel axle 3. The initial state data includes the first initial horizontal distance from the lower intersection point of landing gear buffer 1 to the intersection point of the rocker arm assembly 6. l 1, and the second initial horizontal distance from the center of the axle 3 to the lower intersection point of the landing gear buffer 1. l 3; The current status data includes the first current horizontal distance from the lower intersection point of the landing gear buffer 1 to the intersection point of the rocker arm assembly 6. l 2, and the second current horizontal distance from the center of the axle 3 to the lower intersection point of the landing gear buffer 1. l 4; The vertical deflection distance of the reflective point 8 is obtained based on the initial state data and the current state data. ,include: Based on the first initial horizontal distance l 1 and the first current horizontal distance l 2. Obtain the first horizontal displacement of the lower intersection point of the landing gear buffer 1 relative to the intersection point of the rocker arm assembly 6. l h ; Based on the second initial horizontal distance l 3 and the second current horizontal distance l 4. Obtain the second horizontal displacement of the center of the wheel axle 3 relative to the lower intersection point of the landing gear buffer 1. l lz ; Based on the first horizontal displacement l h and the second horizontal displacement l lz Obtain the total horizontal displacement of the center of the wheel axle 3 relative to the intersection point of the rocker arm assembly 6. L ; Based on the total horizontal displacement L Obtain the vertical deflection distance of the reflective point 8. .

[0056] In this implementation, the complex spatial motion of the rocker-arm landing gear and tire 2 during the drop test is decomposed into key horizontal displacement components for measurement and synthesis. That is, the first horizontal displacement is measured first. lh With the second horizontal displacement l lz The local geometric changes caused by buffer compression and rocker arm rotation are characterized respectively, and then expressed through the total horizontal displacement. L It comprehensively reflects the overall horizontal movement of the center of wheel axle 3 relative to the hinge point of rocker arm assembly 6.

[0057] Based on this total horizontal displacement L Based on the specific geometric configuration of the rocker arm assembly 6, the vertical deflection distance of the reflector point 8 caused by the pure rotation of the rocker arm can be calculated deterministically. This avoids the difficulty of directly measuring angles or spatial coordinates, significantly reducing the difficulty of tire compression and the requirements for equipment.

[0058] At the same time, through this total horizontal displacement L It can separate the current vertical displacement. The vertical displacement component introduced by the rotation of the rocker arm, thus from the current vertical displacement Subtracting this deflection distance from the value yields the pure tire compression, improving the accuracy and reliability of tire compression measurement calculations.

[0059] Further, please refer to Figure 4 The acquisition of initial state data for the rocker arm landing gear and the tire 2 includes: Obtain the first distance L1 between the upper intersection point of the landing gear buffer 1 and the intersection point of the rocker arm assembly 6, the second distance L2 between the lower intersection point of the landing gear buffer 1 and the intersection point of the rocker arm assembly 6, and the third distance between the upper intersection point of the landing gear buffer 1 and the lower intersection point of the landing gear buffer 1. l 3. The first angle between the lower intersection point of the landing gear buffer and the center of the wheel axle 3, the fourth distance L4, the first distance L1, and the second distance L2. The second angle between the fourth distance L4 and the direction of gravity and the third angle between the first distance L1 and the direction of gravity. ; Based on the second distance L2 and the first included angle and the third included angle Obtain the first initial horizontal distance l 1; Based on the fourth distance L4 and the second included angle Obtain the second initial horizontal distance l 3.

[0060] For details, please refer to Figure 4In the diagram, A1 is the upper intersection point of landing gear buffer 1, A2 is the lower intersection point of landing gear buffer 1, B is the intersection point of rocker arm assembly 6, and C is the center position of wheel axle 3. Therefore, the first initial horizontal distance from the lower intersection point of landing gear buffer 1 to the intersection point of rocker arm assembly 6 is... The second initial horizontal distance from the center of the axle 3 to the lower intersection point of the landing gear buffer 1. .

[0061] The step of acquiring the current status data of the rocker arm landing gear and the tire 2 includes: Obtain the axial displacement L5 between the upper intersection point and the lower intersection point of the landing gear buffer 1, and then, based on the axial displacement L5 and the third distance... l 3. Calculate the current distance between the upper and lower intersection points. Based on the first distance L1, the second distance L2, and the current distance of the upper and lower intersection points. Get the change value of the first included angle ; Based on the second distance L2 and the third included angle and the change value of the first included angle Get the first current horizontal distance l 2; Based on the fourth distance L4 and the second included angle and the change value of the first included angle Get the second current horizontal distance l 4.

[0062] For details, please refer to Figure 4 During a drop test of the landing gear, the tires are compressed, and the current distance between the upper and lower intersection points... .

[0063] Please refer to Figure 4 and Figure 5 Using the cosine formula, we can obtain the current value of the first included angle at the current moment. .

[0064] Therefore, the first angle change value .

[0065] Therefore, after the landing gear buffer 1 is compressed, the first current horizontal distance from the lower intersection of the landing gear buffer 1 to the intersection of the rocker arm assembly 6 is... .

[0066] At this time, the lower intersection point of the landing gear buffer 1 is at a first horizontal displacement relative to the intersection point of the rocker arm assembly 6. .

[0067] Similarly, the second current horizontal distance from the center of the wheel axle 3 to the lower intersection point of the landing gear buffer 1 .

[0068] At this time, the center of the wheel axle 3 is in a second horizontal displacement relative to the lower intersection point of the landing gear buffer 1. .

[0069] Therefore, the total horizontal displacement from the center of wheel axle 3 to the intersection point of rocker arm assembly 6 is shown in the following formula: In this implementation, by acquiring and processing a series of key static geometric parameters and dynamic changes between the rocker arm landing gear components, a geometric kinematic calculation model of the rocker arm landing gear and tire 2 is constructed. Thus, without directly measuring the complex spatial trajectory of the drop test, the intermediate variables for solving the tire compression are indirectly calculated.

[0070] Specifically, in the static initial state where the tire 2 and the ground 5 are in critical contact, the first distance L1, the second distance L2, and the third distance are measured. l 3. The fourth distance L4 and the geometric parameters of each key angle reflect the initial configuration of the landing gear, providing accurate initial static data for the indirect calculation of relevant dynamic variables during the subsequent drop test.

[0071] During the dynamic motion of the drop test, this invention directly measures the axial displacement L5 of the landing gear buffer 1, combined with the initial third distance of the landing gear buffer 1. l 3. Determine the real-time change in the distance between the upper and lower intersection points of the buffer, and then calculate the change value of the first included angle based on geometric relationships such as the triangle cosine theorem. Furthermore, the linear compression motion of the buffer is linked to the rotational motion of the rocker arm through geometric constraints.

[0072] Subsequently, based on this dynamically changing angle value, the first current horizontal distance can be updated and calculated in real time. l 2 and the second current horizontal distance l 4. The spatial position and angle changes that are difficult to measure directly in the drop test are transformed into the measurement of the buffer stroke changes that are easy to obtain, which significantly simplifies the measuring device and the measuring process. While having the accuracy of tire compression measurement, it also has good engineering practicality and reliability.

[0073] It should be noted that the landing gear buffer 1, as the core shock-absorbing component of the rocker arm landing gear, is typically an oil-pneumatic or hydropneumatic buffer strut. Its structure mainly includes an outer cylinder and an inner cylinder, or a cylinder and a piston rod, which can generate relative linear motion along the axial direction. In drop tests, when the landing gear is subjected to a vertical impact load, the buffer dissipates energy through the compression and flow of its internal medium. Specifically, this is manifested in the dynamic change of the distance between its upper and lower intersection points with the load, i.e., the current distance between the upper and lower intersection points. As the load changes dynamically, this change is the axial displacement L5.

[0074] This axial linear motion, through the hinged connection between the upper and lower intersection points and the rocker arm assembly 6, directly drives the rocker arm to rotate around its assembly intersection points, thus constituting the unique coupled kinematic characteristics of the rocker arm landing gear. This invention, by accurately measuring this axial displacement L5 and combining it with the fixed geometric dimensions of the rocker arm assembly 6, reversely solves for the real-time rotation angle and other derived geometric parameters of the rocker arm. This allows for the precise separation of the pure tire compression from the measured comprehensive vertical displacement, thereby eliminating the influence of the rocker arm rotation component and the complex trajectory of the contact point on the measurement results.

[0075] Furthermore, the statement based on the total horizontal displacement L Obtain the vertical deflection distance of the reflective point 8. ,include: Based on the total horizontal displacement L and the change value of the first included angle Obtain the vertical deflection distance of the reflective point 8. .

[0076] For details, please refer to Figure 4 The vertical deflection distance of the reflective point 8 .

[0077] It should be noted that the present invention establishes a definite trigonometric relationship between the vertical deflection of the reflective point 8 and the horizontal movement of the tail end of the lower rocker arm to which it is attached during the rotation of the rocker arm around its component intersection point. The specific form of this relationship is determined by the real-time rotation angle of the rocker arm, i.e., the change value of the first included angle. This is determined by the total horizontal displacement, which characterizes the overall horizontal position change of the wheel axle 3 center. L The change in the included angle with the first angle that accurately represents the change in the rocker arm's own rotation angle. By substituting the corresponding geometric relationships, the vertical deflection distance of the reflector point 8 caused purely by the rotation of the rocker arm can be directly calculated. Quantity.

[0078] The above calculation steps avoid additional vertical measurement steps, eliminate potential independent sources of measurement error in this direction, and simplify the measuring device and calculation path. Simultaneously, due to the total horizontal displacement... L Change value of the first included angle All of these are intermediate results obtained from reliable measurements and geometric derivations in the aforementioned steps, which enhances the final vertical deflection distance. The accuracy of the value helps to ultimately improve the accuracy of tire compression measurement.

[0079] Ultimately, as Figure 4 and Figure 5 As shown, the final tire compression is obtained. As shown in the following formula: Furthermore, such as Figure 3 As shown, the preset light source is a laser sensor 9 set at a preset reference point on the ground 5. The laser sensor 9 emits a laser perpendicular to the ground 5, so that the reflective point 8 of the reflector 4 relative to the laser is located at the center position of the wheel axle 3. Then, the initial vertical distance of the reflective point 8 relative to the laser sensor 9 can be obtained through the laser sensor 9, or the current vertical distance of the reflective point 8 relative to the laser sensor 9 can be obtained through the laser sensor 9.

[0080] In this implementation, by fixing the origin and direction of the measurement coordinate system to the ground reference point 5, which is unaffected by the movement of the test piece, and defining a clear vertical measurement axis using a vertical laser beam, the laser sensor 9 can quickly and non-contactly acquire the precise distance of the reflective point 8 relative to itself. Simultaneously, by initially adjusting the laser spot to coincide with the center of the wheel axle 3, a direct geometric correspondence is established between the reflective point 8, the center of the wheel axle 3, and the ground reference point 5 in the vertical direction. This provides accurate static baseline data for subsequently correlating the measured vertical displacement with the spatial motion change process of the lower rocker arm's tail end, thus providing a reliable and efficient core data acquisition method for the entire tire compression measurement method, improving the accuracy and response speed of tire compression measurement.

[0081] Furthermore, such as Figure 3 As shown, obtaining the axial displacement L5 between the upper intersection point and the lower intersection point of the landing gear buffer 1 includes: setting a wire-type displacement sensor 7 in the axial direction of the landing gear buffer 1. The axial displacement L5 between the upper intersection point and the lower intersection point of the landing gear buffer 1 is obtained by the pull-wire displacement sensor 7.

[0082] In this implementation, the axial displacement L5 between the upper and lower intersection points of the landing gear buffer 1 is obtained by directly installing a wire-type displacement sensor 7 along its axial direction. The wire-type displacement sensor 7 features good linearity, strong resistance to shock vibration, and flexible installation, making it suitable for measurement environments with severe, instantaneous impacts, such as drop tests. This wire-type displacement sensor 7 can directly capture the linear compression or elongation displacement of the buffer under impact loads, and is easily recorded and processed synchronously by the data acquisition system.

[0083] This implementation avoids the cumulative errors that may be introduced by complex spatial coordinate back calculation or indirect derivation. At the same time, the installation of this sensor usually does not require complex modifications to the landing gear buffer 1 body, making installation simple and having minimal impact on the mechanical properties of the test piece itself. Thus, while ensuring measurement accuracy, it significantly improves the practicality and reliability of the entire measurement system.

[0084] Further, please refer to Figure 6 Based on the laser sensor 9 and the wire-type displacement sensor 7, the current tire compression at each moment during the drop motion is measured. This allows you to obtain the current tire compression. The time history curve, also known as the compression curve, is as follows: Figure 6 As shown in the figure; the horizontal axis represents the sampling time, and the vertical axis represents the current tire compression. .

[0085] As shown in the figure, when the current tire compression A value greater than 0 indicates the downward compression distance of tire 2. When the current tire compression amount... A value less than 0 indicates the distance the tire jumps off the ground, representing the current tire compression. When the value is 0, it means that tire 2 is just touching the ground 5.

[0086] Finally, by analyzing the compression curve, we can further analyze and measure the motion changes of the rocker arm landing gear tire 2 throughout the entire drop test.

[0087] Please refer to Figure 7 The second aspect of the present invention provides a rocker arm landing gear tire compression measurement system, applicable to rocker arm landing gear and tire 2. The rocker arm landing gear is provided with a landing gear buffer 1 and a rocker arm assembly 6. The upper intersection point of the landing gear buffer 1 is movably connected to the upper rocker arm of the rocker arm assembly 6, and the lower intersection point of the landing gear buffer 1 is movably connected to the lower rocker arm of the rocker arm assembly 6. The intersection point of the movably connected upper and lower rocker arms is the intersection point of the rocker arm assembly 6. The tail end of the lower rocker arm is movably connected to the wheel axle 3 of the tire 2. The measurement system includes: A reflector 4 is set at the tail end of the lower rocker arm, a laser sensor 9 is set at a preset reference point on the ground 5, and a wire-type displacement sensor 7 is set in the axial direction of the landing gear buffer 1, wherein the laser sensor 9 emits a laser perpendicular to the ground 5. The initial data measurement module 100 is used to make the lower edge of the tire 2 in a critical contact state with the ground 5, so that the reflector 4 and the reflective point 8 of the laser are located at the center position of the wheel axle 3, and then the laser sensor 9 obtains the initial vertical distance of the reflective point 8 relative to the light source, and obtains the initial state data of the rocker arm landing gear and the tire 2. The drop test module 200 is used to drive the rocker arm landing gear and the tire 2 to perform drop test movements, and to make the reflector 4 rotate together with the lower rocker arm; The current data measurement module 300 is used to acquire the current vertical distance of the reflective point 8 relative to the light source at any moment during the earthquake motion via the laser sensor 9, and then calculate the current vertical displacement based on the initial vertical distance and the current vertical distance. The current status data of the rocker arm landing gear and the tire 2 are obtained through the pull-wire displacement sensor 7. The tire compression calculation module 400 is used to obtain the vertical deflection distance of the reflective point 8 based on the initial state data and the current state data. This will further reduce the current vertical displacement. Subtract the vertical deflection distance To obtain the current tire compression Complete the tire compression measurement.

[0088] The method and system for measuring tire compression of a rocker-arm landing gear provided by the present invention have at least the following advantages compared with the prior art: First, the present invention utilizes a simple measuring device and a precise measuring method to achieve real-time dynamic measurement of tire pressure. The measured data can be used to evaluate the actual working performance of the tire, providing a reliable experimental basis for optimizing the cushioning performance of the landing gear system.

[0089] Secondly, the measurement method described in this invention is used to measure the tire compression of rocker-arm landing gear, which can significantly improve the efficiency and accuracy of drop tests. At the same time, it solves the problem of high cost of high-speed camera measurement hardware. It has the advantages of being easy to use, simple to install, reducing test investment costs, and fast measurement, and is suitable for widespread use in landing gear drop tests.

[0090] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0091] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described; however, any combination of these technical features that does not contradict each other should be considered within the scope of this specification.

[0092] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various improvements and substitutions without departing from the concept of this application, and these improvements and substitutions should also be considered within the scope of protection of this invention. Therefore, the scope of protection of this application should be determined by the appended claims.

Claims

1. A method for measuring the tire compression of a rocker arm landing gear, characterized in that, This method is applicable to rocker-arm landing gear and tires. The rocker-arm landing gear is equipped with a landing gear buffer and a rocker arm assembly. The upper intersection point of the landing gear buffer is movably connected to the upper rocker arm of the rocker arm assembly, and the lower intersection point of the landing gear buffer is movably connected to the lower rocker arm of the rocker arm assembly. The intersection point of the movably connected upper and lower rocker arms is the intersection point of the rocker arm assembly. The tail end of the lower rocker arm is movably connected to the wheel axle of the tire. The method includes the following steps: A reflector is provided at the tail end of the lower rocker arm; The lower edge of the tire is brought into critical contact with the ground, so that the reflective point of the reflector relative to the preset light source is located at the center of the wheel axle. The initial vertical distance of the reflective point relative to the light source is then obtained, and the initial state data of the rocker arm landing gear and the tire are obtained. The rocker arm landing gear and the tires are driven to perform a drop-shock motion, and the reflector rotates together with the lower rocker arm. At any moment during the drop motion, the current vertical distance of the reflective point relative to the light source is obtained, and then the current vertical displacement is calculated based on the initial vertical distance and the current vertical distance, and the current state data of the rocker arm landing gear and the tires are obtained. Based on the initial state data and the current state data, the vertical deflection distance of the reflective point is obtained, and then the current vertical displacement is subtracted from the vertical deflection distance to obtain the current tire compression, thus completing the tire compression measurement.

2. The method for measuring tire compression of a rocker-arm landing gear according to claim 1, characterized in that, The initial state data includes a first initial horizontal distance from the lower intersection of the landing gear buffer to the intersection of the rocker arm assembly, and a second initial horizontal distance from the center of the wheel axle to the lower intersection of the landing gear buffer; the current state data includes a first current horizontal distance from the lower intersection of the landing gear buffer to the intersection of the rocker arm assembly, and a second current horizontal distance from the center of the wheel axle to the lower intersection of the landing gear buffer. The step of obtaining the vertical deflection distance of the reflective point based on the initial state data and the current state data includes: The first horizontal displacement of the lower intersection point of the landing gear buffer relative to the intersection point of the rocker arm assembly is obtained based on the first initial horizontal distance and the first current horizontal distance. The second horizontal displacement of the center of the wheel axle relative to the lower intersection point of the landing gear buffer is obtained based on the second initial horizontal distance and the second current horizontal distance; The total horizontal displacement of the center of the wheel axle relative to the intersection point of the rocker arm assembly is obtained based on the first horizontal displacement and the second horizontal displacement. The vertical deflection distance of the reflective point is obtained based on the total horizontal displacement.

3. The method for measuring tire compression of a rocker-arm landing gear according to claim 2, characterized in that, The acquisition of initial state data for the rocker-arm landing gear and the tires includes: The following parameters are obtained: a first distance between the upper intersection point of the landing gear buffer and the intersection point of the rocker arm assembly; a second distance between the lower intersection point of the landing gear buffer and the intersection point of the rocker arm assembly; a third distance between the upper intersection point of the landing gear buffer and the lower intersection point of the landing gear buffer; a fourth distance between the lower intersection point of the landing gear buffer and the center of the wheel axle; a first angle between the first distance and the second distance; a second angle between the fourth distance and the direction of gravity; and a third angle between the first distance and the direction of gravity. The first initial horizontal distance is obtained based on the second distance, the first included angle, and the third included angle; the second initial horizontal distance is obtained based on the fourth distance and the second included angle. The acquisition of the current status data of the rocker arm landing gear and the tires includes: The axial displacement of the upper intersection point and the lower intersection point of the landing gear buffer is obtained, and the current distance between the upper and lower intersection points is calculated based on the axial displacement and the third distance; the change value of the first included angle is obtained based on the first distance, the second distance and the current distance between the upper and lower intersection points. The first current horizontal distance is obtained based on the second distance, the third included angle, and the change value of the first included angle; the second current horizontal distance is obtained based on the fourth distance, the second included angle, and the change value of the first included angle.

4. The method for measuring tire compression of a rocker-arm landing gear according to claim 3, characterized in that, The step of obtaining the vertical deflection distance of the reflective point based on the total horizontal displacement includes: Based on the total horizontal displacement and the first angle change value, the vertical deflection distance of the reflective point is obtained.

5. The method for measuring tire compression of a rocker-arm landing gear according to claim 3, characterized in that, The preset light source is a laser sensor set at a preset reference point on the ground. The laser sensor emits a laser perpendicular to the ground, so that the reflective point of the reflector relative to the laser is located at the center of the wheel axle. Then, the initial vertical distance of the reflective point relative to the laser sensor is obtained through the laser sensor, or the current vertical distance of the reflective point relative to the laser sensor is obtained through the laser sensor.

6. The method for measuring tire compression of a rocker-arm landing gear according to claim 3, characterized in that, The step of obtaining the axial displacement of the upper intersection point and the lower intersection point of the landing gear buffer includes: setting a wire-type displacement sensor in the axial direction of the landing gear buffer; The axial displacement of the upper intersection point and the lower intersection point of the landing gear buffer is obtained by the pull-wire displacement sensor.

7. A rocker arm landing gear tire compression measurement system, characterized in that, This measurement system is applicable to rocker-arm landing gear and tires. The rocker-arm landing gear includes a landing gear buffer and a rocker arm assembly. The upper intersection point of the landing gear buffer is movably connected to the upper rocker arm of the rocker arm assembly, and the lower intersection point of the landing gear buffer is movably connected to the lower rocker arm of the rocker arm assembly. The intersection point of the movably connected upper and lower rocker arms is the intersection point of the rocker arm assembly. The tail end of the lower rocker arm is movably connected to the wheel axle of the tire. The system includes: A reflector is set at the tail end of the lower rocker arm, a laser sensor is set at a preset reference point on the ground, and a wire-type displacement sensor is set along the axial direction of the landing gear buffer, wherein the laser sensor emits a laser perpendicular to the ground. The initial data measurement module is used to bring the lower edge of the tire to a critical contact state with the ground, so that the reflective point of the reflector relative to the laser is located at the center of the wheel axle. Then, the laser sensor obtains the initial vertical distance of the reflective point relative to the light source, and obtains the initial state data of the rocker arm landing gear and the tire. The drop test module is used to drive the rocker arm landing gear and the tire to perform drop test movements, and to make the reflector rotate together with the lower rocker arm; The current data measurement module is used to obtain the current vertical distance of the reflective point relative to the light source at any moment during the drop motion through the laser sensor, and then calculate the current vertical displacement based on the initial vertical distance and the current vertical distance, and obtain the current state data of the rocker arm landing gear and the tire through the pull-wire displacement sensor. The tire compression calculation module is used to obtain the vertical deflection distance of the reflective point based on the initial state data and the current state data, and then subtract the vertical deflection distance from the current vertical displacement to obtain the current tire compression, thus completing the tire compression measurement.

8. The rocker arm landing gear tire compression measurement system according to claim 7, characterized in that, The initial state data includes a first initial horizontal distance from the lower intersection of the landing gear buffer to the intersection of the rocker arm assembly, and a second initial horizontal distance from the center of the wheel axle to the lower intersection of the landing gear buffer; the current state data includes a first current horizontal distance from the lower intersection of the landing gear buffer to the intersection of the rocker arm assembly, and a second current horizontal distance from the center of the wheel axle to the lower intersection of the landing gear buffer. The step of obtaining the vertical deflection distance of the reflective point based on the initial state data and the current state data includes: The first horizontal displacement of the lower intersection point of the landing gear buffer relative to the intersection point of the rocker arm assembly is obtained based on the first initial horizontal distance and the first current horizontal distance. The second horizontal displacement of the center of the wheel axle relative to the lower intersection point of the landing gear buffer is obtained based on the second initial horizontal distance and the second current horizontal distance; The total horizontal displacement of the center of the wheel axle relative to the intersection point of the rocker arm assembly is obtained based on the first horizontal displacement and the second horizontal displacement. The vertical deflection distance of the reflective point is obtained based on the total horizontal displacement.

9. A rocker arm landing gear tire compression measurement system according to claim 8, characterized in that, The acquisition of initial state data for the rocker-arm landing gear and the tires includes: The following parameters are obtained: a first distance between the upper intersection point of the landing gear buffer and the intersection point of the rocker arm assembly; a second distance between the lower intersection point of the landing gear buffer and the intersection point of the rocker arm assembly; a third distance between the upper intersection point of the landing gear buffer and the lower intersection point of the landing gear buffer; a fourth distance between the lower intersection point of the landing gear buffer and the center of the wheel axle; a first angle between the first distance and the second distance; a second angle between the fourth distance and the direction of gravity; and a third angle between the first distance and the direction of gravity. The first initial horizontal distance is obtained based on the second distance, the first included angle, and the third included angle; the second initial horizontal distance is obtained based on the fourth distance and the second included angle. The acquisition of current status data of the rocker arm landing gear and the tires via the wire-type displacement sensor includes: The axial displacement of the upper intersection point and the lower intersection point of the landing gear buffer are obtained by the pull-wire displacement sensor, and the current distance between the upper and lower intersection points is calculated based on the axial displacement and the third distance; the change value of the first included angle is obtained based on the first distance, the second distance and the current distance between the upper and lower intersection points. The first current horizontal distance is obtained based on the second distance, the third included angle, and the change value of the first included angle; the second current horizontal distance is obtained based on the fourth distance, the second included angle, and the change value of the first included angle.

10. A rocker arm landing gear tire compression measurement system according to claim 9, characterized in that, The step of obtaining the vertical deflection distance of the reflective point based on the total horizontal displacement includes: Based on the total horizontal displacement and the first angle change value, the vertical deflection distance of the reflective point is obtained.

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