Multi-degree-of-freedom dynamic lateral force loading device, test bench and control method thereof

Abstract

This application discloses a multi-degree-of-freedom dynamic lateral force loading device, test bench, and control method. The device includes a base frame (1), an orthogonal actuation system, and a dynamic controller (11). The base frame is provided with a guide rail fixing seat (2) that can slide along the crossbeam (14) of the test bench; the orthogonal actuation system includes two electric cylinders (7) arranged at a 90° angle, one end of which is hinged to the base frame, and the other end is connected in sequence to a force sensor (8) and a vibration damper mounting fixture (9), and the fixture is provided with two orthogonally arranged sensor fixing seats (10); the dynamic controller receives the target resultant force vector, controls the output of the two electric cylinders based on the vector decomposition principle, and performs closed-loop calibration through force sensor feedback to realize dynamic lateral force loading with continuously adjustable direction from 0° to 360° and programmable frequency from 0 to 10Hz. This application solves the problem that existing test benches cannot reproduce multi-angle dynamic lateral loads.

Description

Technical Field

[0001] This application relates to the field of vibration damper performance testing technology, and more specifically, to a multi-degree-of-freedom dynamic lateral force loading device for a vibration damper durability test bench, a vibration damper durability test bench including the device, and a corresponding multi-degree-of-freedom dynamic lateral force loading control method. Background Technology

[0002] Traditional vibration damper durability test benches typically simulate only the reciprocating motion of a piston along a single axis, failing to reproduce the multi-angle dynamic lateral loads experienced by vibration dampers during actual rail vehicle operation. This leads to discrepancies between test results and real-world conditions, reducing the effectiveness of durability testing. Some test benches incorporate lateral force loading mechanisms, but these have limitations, including: using a single actuator or fixed mechanical lever structure, resulting in a single force direction and inability to achieve 360° planar vector switching; relying on open-loop control methods such as mechanical counterweights and pneumatic pressure regulation, limiting the application of only static lateral forces or having insufficient upper limits on loading frequencies (typically <1Hz), and the inability to program dynamic load spectra. Existing technologies can only apply static lateral forces in a fixed direction, lacking the ability to adjust direction, perform dynamic loading, or apply lateral forces in any direction within a plane, resulting in a single force direction.

[0003] Therefore, there is an urgent need for a multi-angle dynamic lateral force loading device that can precisely control the direction and frequency, in order to solve the technical bottleneck of the lack of multi-directional dynamic load in the durability test of vibration dampers. Summary of the Invention

[0004] This application aims to provide a multi-angle dynamic lateral force loading device that can precisely control the direction and frequency. It can be flexibly installed on existing vibration damper durability test benches. It utilizes an orthogonal composite lateral force loading mechanism to apply multi-directional loads of different directions, magnitudes, and frequencies through a closed-loop dynamic control system.

[0005] To address the aforementioned technical problems, this application provides a multi-degree-of-freedom dynamic lateral force loading device in its first aspect, applied to a vibration damper durability test bench, comprising: a base frame for mounting on the vibration damper durability test bench; an orthogonal actuation system including two electric cylinders arranged orthogonally, one end of each electric cylinder being connected to the base frame via a hinge, and the other end being connected to a vibration damper mounting fixture via a force sensor, the vibration damper mounting fixture being used to fix the vibration damper to be tested on the outer periphery; and a dynamic controller electrically connected to the two electric cylinders and the two force sensors respectively, for receiving force signals fed back from the force sensors and generating output commands for the two electric cylinders.

[0006] In some embodiments, the base frame includes a plurality of guide rail fixing seats, which are slidably mounted on the crossbeam of the damper durability test bench and fixed by locking members to adjust the position of the lateral force applied to the damper.

[0007] In some embodiments, the guide rail mounting base has a clamping structure adapted to the cross-sectional shape of the beam of the damper durability test bench. The size of the clamping structure can be customized according to the cross-sectional size of the beam to avoid interference with the existing structure of the damper durability test bench.

[0008] In some embodiments, the base frame includes: four longitudinal beams, two transverse beams, and two actuator mounting seats; actuator mounting seats are respectively provided at both ends of the transverse beams for hinged connection of electric cylinders. The longitudinal beams and transverse beams are detachably assembled by bolts.

[0009] In some embodiments, the shock absorber mounting fixture is provided with two sensor mounting seats arranged orthogonally at 90°. A force sensor is fixedly connected to the upper end face of each sensor mounting seat, and an electric cylinder is fixedly connected to the upper end face of the force sensor. The shock absorber mounting fixture and the force sensor are connected by a detachable threaded connection, and the shock absorber mounting fixture includes replaceable sleeves with various inner diameter specifications to adapt to shock absorbers of different diameters.

[0010] In some embodiments, the hinge structure between the electric cylinder and the base frame is a single-axis hinge or a ball hinge, used to compensate for the influence of base frame assembly errors on the direction of force application.

[0011] In a second aspect, this application provides a vibration damper durability test bench, comprising: a test bench base, equipped with an axial actuation system for driving the piston of the vibration damper to perform axial reciprocating motion; a multi-degree-of-freedom dynamic lateral force loading device as described in any of the preceding claims, mounted on the crossbeam of the test bench base; and a main controller, communicatively connected to the axial actuation system and the dynamic controller, for coordinating and controlling the timing of axial motion and lateral loading.

[0012] In a third aspect, this application provides a multi-degree-of-freedom dynamic lateral force loading control method using the aforementioned device. The method includes the following steps: mounting a vibration damper on a durability test bench and fixing the vibration damper mounting fixture to the outer periphery of the damper; inputting the magnitude and direction of the target resultant force vector into the dynamic controller; the dynamic controller calculating and generating output commands for two orthogonal electric cylinders based on the target resultant force vector; real-time feedback of the actual output force from a force sensor, with the dynamic controller correcting the output commands based on the feedback value; and simultaneously applying a preset lateral force while the vibration damper is subjected to axial piston movement. This method achieves time synchronization between axial movement and lateral loading, significantly improving the loading accuracy of the lateral force and providing a standardized operating procedure.

[0013] In some embodiments, the step of the dynamic controller calculating and generating the output force command includes: decomposing the target resultant force vector into two orthogonal force components, the magnitudes of which are determined by multiplying the magnitude of the target resultant force vector by the trigonometric function value of the corresponding direction angle.

[0014] In some embodiments, by adjusting the ratio of the output values ​​of the two electric cylinders, the direction of the resultant force can be continuously adjusted within the range of 0° to 360°.

[0015] In some embodiments, the magnitude of the resultant force is precisely adjusted by synchronously adjusting the output values ​​of the two electric cylinders.

[0016] In some embodiments, the dynamic controller supports constant force static loading mode, frequency sweep sine wave dynamic loading mode, and random spectrum load dynamic loading mode. The constant force mode is used to simulate long-term static lateral force action to test the static creep and sealing performance of the vibration damper; the frequency sweep sine wave mode is used to test the frequency response characteristics of the vibration damper under lateral excitation at different frequencies; the random spectrum mode is based on data collected from actual lines to most realistically simulate the random lateral loads of rail vehicles in actual operation.

[0017] In some embodiments, the frequency range of the swept sinusoidal dynamic loading mode is 0 to 10 Hz, and the sweep frequency pattern is linear or logarithmic. The 0~10Hz frequency range covers the lateral excitation frequency range of most passenger car suspension systems; linear / logarithmic sweep frequency is selectable to meet different testing requirements.

[0018] In some embodiments, the random spectrum load dynamic loading mode generates a random load spectrum based on lateral force data collected from actual roads. By importing data collected from actual roads, load reproduction from "road to laboratory" is achieved, greatly improving the accuracy and confidence of vibration damper fatigue life assessment.

[0019] In some embodiments, the method further includes: the dynamic controller communicating with the main control system of the damper durability test bench to synchronously collect force data of the axial piston movement of the damper, and combining this with lateral force data fed back by the force sensor to generate a dynamometer diagram reflecting the influence of lateral force on the damper's damping characteristics. The generated comprehensive dynamometer diagram can intuitively display how the damping force-displacement curve of the damper changes when lateral forces of different directions, magnitudes, and frequencies are applied, and can quantitatively analyze phenomena such as damping force attenuation, hysteresis loop area change, and dynamometer diagram distortion caused by lateral force.

[0020] In some embodiments, the steps of the dynamic controller performing closed-loop control include: receiving the target resultant force vector input by the operator, generating initial commands for the two electric cylinders according to a vector decomposition algorithm, reading the feedback value of the force sensor in real time during the operation of the electric cylinders, comparing it with the target value, and correcting the output command. Through real-time closed-loop correction, the force sensor feedback is read at a sampling frequency of over 1000Hz, and the output command is quickly corrected using algorithms such as PID, so that the actual resultant force vector tracks the target value in real time; even under rapidly changing operating conditions such as frequency sweep or random spectrum, the loading error can be guaranteed to be within the allowable range; and long-term errors caused by factors such as electric cylinder wear, temperature drift, and installation gaps are automatically compensated.

[0021] The beneficial effects of this application are as follows: Through vector synthesis control of orthogonal electric cylinders, dynamic loading in any direction within a 360° plane can be achieved, accurately reproducing lateral torque and alternating tension / compression; the electric cylinders connect the damper's force application point through a hinge mechanism, achieving interference-free multi-directional force transmission; static and dynamic lateral forces can be applied, and multi-dimensional loads can be applied simultaneously in a single test through programming, shortening the verification cycle for complex working conditions; combined with durability test conditions, it can better simulate and analyze the performance of the damper in real-world applications, providing a high-confidence test environment for damper fatigue life assessment. Attached Figure Description

[0022] The above and other objects, features, and advantages of exemplary embodiments of this application will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings. Embodiments of this application are illustrated in the drawings by way of example and not limitation, wherein:

[0023] Figure 1 This is a schematic diagram of the overall structure of the multi-degree-of-freedom dynamic lateral force loading device for a vibration damper durability test bench according to an embodiment of this application. Figure 2 This is a schematic diagram of a vibration damper durability test bench according to an embodiment of this application; Figure 3 This is a schematic diagram illustrating the lateral force direction control principle of an embodiment of this application; Figure 4 This is a flowchart of the closed-loop control of the dynamic controller according to an embodiment of this application.

[0024] In the accompanying drawings, the same or corresponding reference numerals indicate the same or corresponding parts: 1-Base frame, 2-Guide rail fixing seat, 3-Longitudinal beam, 4-Cross beam, 5-Actuator mounting seat, 7-Electric cylinder, 8-Force sensor, 9-Damper mounting fixture, 10-Sensor fixing seat, 11-Dynamic controller, 12-Hinge, 13-Bolt, 14-Test bench crossbeam, 15-Damper. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] It should be understood that the terms "comprising" and "including" used in the specification and claims of this application indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0027] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application. As used in this specification and claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0028] The specific embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0029] like Figure 1 As shown in the figure, this embodiment provides a multi-degree-of-freedom dynamic lateral force loading device for a vibration damper durability test bench. The device mainly includes a base frame 1, an orthogonal actuation system, and a dynamic controller 11.

[0030] like Figure 2 As shown, this application also provides a vibration damper durability test bench, which includes a test bench base, an axial actuation system disposed on the test bench base, and the aforementioned multi-degree-of-freedom dynamic lateral force loading device installed on the crossbeam 14 of the test bench base.

[0031] The base frame 1 is used for mounting to the vibration damper durability test bench and serves as the supporting foundation for the entire loading device. The base frame 1 consists of four guide rail fixing seats 2, four longitudinal beams 3, two transverse beams 4, and two actuator mounting seats 5. The vibration damper mounting fixture 9 is connected to the electric cylinder 7 via a force sensor 8 and is used to clamp the vibration damper 15.

[0032] The guide rail fixing seat 2 is the connecting component between the base frame 1 and the vibration damper durability test bench. Each guide rail fixing seat 2 is slidably mounted on the crossbeam 14 of the vibration damper durability test bench and can slide in a direction parallel to the axial direction of the vibration damper 15. By sliding the guide rail fixing seat 2, the application position of the lateral load on the vibration damper 15 can be adjusted to adapt to different specifications of vibration dampers or different lateral force application point requirements. After the guide rail fixing seat 2 slides to the desired position, it is locked and fixed by bolts 13 and other locking components to prevent displacement during the test. The guide rail fixing seat 2 has a clamping structure that is adapted to the cross-sectional shape of the crossbeam 14 of the vibration damper durability test bench. The size of this clamping structure can be customized according to the cross-sectional dimensions of the crossbeam 14, as long as it avoids interference with the existing structure of the vibration damper durability test bench. This modular design allows the device to be flexibly adapted to various existing test bench frames.

[0033] The support frame is assembled from four longitudinal beams 3 and two transverse beams 4 using bolts 13. Both the longitudinal beams 3 and transverse beams 4 are made of profiles (such as square steel or aluminum profiles), connected by bolts to form a stable rectangular frame structure. This assembly method is simple in structure, easy to disassemble and transport, and also allows for easy adjustment of the frame size according to different testing requirements. Actuator mounting seats 5 are provided at both ends of the two transverse beams 4, used to hinge one end of the electric cylinder 7. The actuator mounting seats 5 have hinge holes for mounting hinges 12.

[0034] The damper mounting clamp 9 is used to help fix the damper 15 and ensure that the damper 15 maintains the correct posture during the test.

[0035] The orthogonal actuation system is the core execution part of this device, comprising two electric cylinders 7 arranged orthogonally (one on each side, or one each in the X and Y directions). Each electric cylinder 7 is a high-precision servo electric cylinder, which has advantages such as fast response speed, high positioning accuracy, and programmable output control. The rear end of the cylinder body of the electric cylinder 7 is provided with a hinge lug that mates with the hinge structure.

[0036] Two electric cylinders 7 are respectively mounted on corresponding actuator mounting bases 5. Specifically, the rear end of the cylinder body (or the distal end of the piston rod) of each electric cylinder 7 is connected to the actuator mounting base 5 via a hinge 12. The hinge 12 can be a single-axis hinge or a ball joint, allowing the electric cylinder 7 to swing within a certain angle range around the hinge point during force application. This hinged connection method can compensate for installation errors generated during frame assembly, avoid additional interference to the direction of force application due to axis misalignment, and ensure that the force applied by the electric cylinder 7 can be accurately transmitted along the design direction.

[0037] Each electric cylinder 7 has a force sensor 8 connected to the front end (or output end) of its piston rod. The force sensor 8 is a high-precision strain gauge force sensor with threaded holes on both ends for connecting the electric cylinder 7 and the vibration damper mounting fixture 9. The force sensor 8 is used to detect the force applied by the electric cylinder 7 to the vibration damper mounting fixture 9 in real time. The other end of the force sensor 8 is connected to the vibration damper mounting fixture 9 via a threaded connection. The vibration damper mounting fixture 9 is used to securely clamp the vibration damper 15 under test (i.e., the damper cylinder body). The threaded connection between the vibration damper mounting fixture 9 and the force sensor 8 facilitates easy assembly and disassembly, and allows for easy replacement of fixtures of different specifications.

[0038] Specifically, the shock absorber mounting fixture 9 is equipped with two sensor mounting seats 10. These two sensor mounting seats 10 are arranged orthogonally at 90°, and the upper and lower end faces of each sensor mounting seat 10 are parallel. The lower (inner) end face is fixedly connected to the main body of the shock absorber mounting fixture 9, and the upper (outer) end face is fixedly connected to the force sensor 8. The output end of the electric cylinder 7 is fixedly connected to the upper end face of the force sensor 8. In this way, the tension or pressure applied by the two electric cylinders 7 is orthogonal in space and does not interfere with each other. That is, when the two electric cylinders 7 output forces Fx and Fy respectively, these two forces combine into a resultant force F on the shock absorber mounting fixture 9. The direction of this resultant force is determined by the ratio of Fx and Fy, and its magnitude is determined by the square root of the sum of the squares of Fx and Fy.

[0039] The damper mounting fixture 9 can be configured and replaced according to the different diameters of the damper 15. For example, for dampers of different diameters, fixture sleeves with different inner diameters can be selected and quickly replaced via threaded connections to meet the testing needs of various specifications of dampers.

[0040] The dynamic controller 11 is the intelligent control core of the device, electrically connected to the two electric cylinders 7 and the two force sensors 8. The dynamic controller 11 integrates a microprocessor, signal conditioning circuitry, power drive module, and human-machine interface (such as a touchscreen, buttons, and a display). The dynamic controller 11 receives real-time force signals from the force sensors 8 and generates output commands for each of the two electric cylinders 7. The dynamic controller 11 also has a communication interface for communicating with the main control system of the vibration damper durability test bench to achieve data exchange and collaborative control.

[0041] like Figure 3 As shown, this application achieves the synthesis of lateral forces of arbitrary direction and magnitude in a plane by independently controlling the output of two orthogonally arranged electric cylinders 7.

[0042] Let the output force of the X-axis electric cylinder be Fx, and the output force of the Y-axis electric cylinder be Fy (Fx and Fy can be positive values ​​representing thrust and negative values ​​representing tension). Then the resultant force vector F = (Fx, Fy). The magnitude of the resultant force F is determined by the following formula: |F| = The angle θ between the direction of the resultant force F and the X-axis satisfies: tanθ = Fy / Fx.

[0043] Therefore, by independently controlling Fx and Fy, the entire XY plane vector space can be covered: Direction control: By adjusting the ratio of Fx to Fy, the direction of the resultant force can be continuously adjusted within the range of 0° to 360°. For example, if a resultant force direction of 45° is required, set Fx = Fy; if a resultant force direction of 90° (vertically upward) is required, set Fx = 0, and Fy is a positive thrust; if a resultant force direction of -90° (vertically downward) is required, set Fx = 0, and Fy is a negative tension (i.e., a pulling force).

[0044] Size control: Adjustment The value of k allows for precise adjustment of the output force. For example, while keeping the direction angle θ constant, multiplying both Fx and Fy by the same coefficient k will increase the magnitude of the resultant force to k times its original value, while keeping the direction unchanged.

[0045] Specific application examples: A downward force of 1500N needs to be applied (-Y direction): Let Fx=0, Fy=-1500N (that is, apply a pulling force of 1500N to the electric cylinder in the Y direction).

[0046] A horizontal force of 1000N needs to be applied to the left (-X direction): Let Fx = -1000N (tension), Fy = 0.

[0047] A force of 1500N needs to be applied at a 45° angle to the X-axis: Let Fx = Fy = 1060.7N (because 1060.7² + 1060.7² = 1500²).

[0048] A force of 1000N needs to be applied in the upper left 45° direction (135°): Let Fx = -707.1N (tension) and Fy = +707.1N (thrust).

[0049] The dynamic controller 11 internally stores the aforementioned vector decomposition algorithm. The operator only needs to input the magnitude and direction angle of the target resultant force on the control interface, and the controller automatically calculates Fx and Fy, and drives the two electric cylinders to output the corresponding tension or pressure.

[0050] Dynamic controller 11 performs as follows Figure 4The closed-loop control flow is shown below. In specific operation, the damper 15 to be tested is first installed on the durability test bench, and the damper mounting fixture 9 is fixed to the outer periphery of the damper 15. Then, test parameters are set on the human-machine interface of the dynamic controller 11, including the target force value (magnitude), direction angle, loading speed, and control mode (static loading, dynamic loading, or frequency sweep test). After loading is started, the dynamic controller 11 performs vector decomposition according to the resultant force vector algorithm, calculates Fx and Fy, and drives the two electric cylinders 7 to execute. The force sensor 8 measures the current actual output force in real time and feeds the signal back to the dynamic controller 11. The dynamic controller 11 compares the actual value with the target value. If the deviation is within the allowable range (e.g., ±1%), the current command is maintained and loading continues; if the deviation exceeds the allowable range, the output command of the electric cylinder 7 is corrected according to the magnitude and direction of the deviation (e.g., through a PID algorithm) until the deviation returns to the allowable range. Meanwhile, the display shows the resultant force vector loading status in real time (such as vector diagrams, numerical values, etc.). Combined with the existing damper force value dynamometer diagram on the durability test bench, the influence of lateral force loading conditions on the damper 15 damping characteristics can be analyzed in real time.

[0051] Specifically, the steps of “generating output commands based on vector decomposition algorithm” include: First, the dynamic controller (11) receives the target resultant force magnitude F and target direction angle θ input by the operator; second, the controller calls the internally stored trigonometric function table or calculates the values ​​of cosθ and sinθ through the CORDIC algorithm; then, the target output values ​​of the X-direction electric cylinder and the Y-direction electric cylinder are calculated according to the formulas Fx = F·cosθ and Fy = F·sinθ respectively; finally, these target values ​​are converted into corresponding current or voltage commands and sent to the servo driver of the electric cylinder (7).

[0052] Dynamic Controller 11 supports the following three main loading modes: Constant force static loading mode: The dynamic controller 11 controls two electric cylinders 7 to output a lateral force of constant magnitude and direction. This mode is used to simulate the durability performance of the shock absorber under static lateral force, such as the constant lateral force experienced by the shock absorber when a rail vehicle is parked on a slope for a long time.

[0053] Sweep-frequency sinusoidal dynamic loading mode: The dynamic controller 11 controls the two electric cylinders 7 to output a sinusoidal lateral force with a continuously varying frequency according to a preset law (such as linear or logarithmic), while maintaining a constant target force amplitude. The sweep frequency range can be arbitrarily set between 0 and 10 Hz, and the sweep frequency law can be selected as linear or logarithmic. This mode is used to test the dynamic response characteristics of the vibration damper under lateral excitation at different frequencies, such as simulating the alternating lateral force borne by the vibration damper when a rail vehicle passes through a turnout at different operating speeds.

[0054] Random Spectrum Load Dynamic Loading Mode: The dynamic controller 11 calculates and controls the two electric cylinders 7 to output corresponding random lateral forces in real time based on pre-imported random load spectrum data (such as lateral force time history data collected from actual roads). This mode can most realistically simulate the complex random lateral loads that the shock absorber experiences during actual road driving.

[0055] The dynamic controller 11 supports a dynamic loading frequency range of 0 to 10 Hz, which can meet the simulation requirements of most dynamic lateral forces.

[0056] This device is mounted on the crossbeam 14 of an existing vibration damper durability test bench via a guide rail fixing seat 2. During installation, first, the guide rail fixing seat 2 is fitted onto the crossbeam 14 and slid to the desired position (aligning the lateral force application point with the appropriate part of the vibration damper 15), then tightened with bolts 13. The vibration damper mounting clamp 9 is fixed to the outer periphery of the vibration damper 15. The axial actuation system of the durability test bench drives the piston of the vibration damper 15 to perform axial reciprocating motion (simulating the vertical vibration of a rail vehicle during operation). Simultaneously, the dynamic controller 11 of this device applies a preset planar lateral force.

[0057] The dynamic controller 11 can communicate with the main control system of the vibration damper durability test bench. On one hand, the dynamic controller 11 sends the current lateral force data to the main control system; on the other hand, the main control system sends the force data of the axial piston movement of the vibration damper 15 (e.g., dynamometer diagram data) to the dynamic controller 11. The dynamic controller 11 synchronously fuses the lateral force data and axial force data to generate a comprehensive dynamometer diagram reflecting the influence of the lateral force on the damping characteristics of the vibration damper 15. Operators can analyze this dynamometer diagram to evaluate the impact of the lateral force on the damper's damping force, hysteresis characteristics, fatigue life, and other performance indicators.

[0058] like Figure 2 As shown, the vibration damper durability test bench includes a test bench base, an axial actuation system, a multi-degree-of-freedom dynamic lateral force loading device as described above, and a main controller.

[0059] The test bench base is used to install and support the various components. An axial actuation system (typically a hydraulic servo actuator or an electric cylinder) is mounted on the test bench base to drive the piston of the damper 15 in axial reciprocating motion, simulating the vertical vibration of a rail vehicle during operation. A multi-degree-of-freedom dynamic lateral force loading device is mounted on the crossbeam 14 of the test bench base via its guide rail mounting base 2. The main controller is communicatively connected to the axial actuation system and the dynamic controller 11 to coordinate the timing relationship between axial motion and lateral loading. For example, the main controller can control the axial motion to trigger a lateral force loading event at a specific phase angle to simulate specific operating conditions (such as the lateral impact of a rail vehicle passing through a rail joint).

[0060] This application also provides a multi-degree-of-freedom dynamic lateral force loading control method using the above-mentioned device, comprising the following detailed steps: Step S1: Install the vibration damper. Install the vibration damper 15 to be tested on the vibration damper durability test bench, ensuring that the piston rod of the vibration damper 15 is connected to the axial actuation system, and the cylinder of the vibration damper 15 is fixed by the vibration damper mounting clamp 9.

[0061] Step S2: Set test parameters. Input the magnitude, direction angle, and loading waveform (such as constant force, swept sine wave, random spectrum, etc.) of the target resultant force vector on the human-machine interface of the dynamic controller 11. The operator can also select a pre-stored test condition template.

[0062] Step S3: Vector Decomposition. Based on the input resultant force vector target value, the dynamic controller 11 calculates the target output values ​​Fx and Fy of the two electric cylinders 7 using a vector decomposition algorithm (Fx=F·cosθ, Fy=F·sinθ). The magnitudes of the two component forces are determined by multiplying the magnitude of the target resultant force vector by the trigonometric function value of the corresponding direction angle. This step automatically calculates the output command from the target resultant force to the two electric cylinders. The operator only needs to input the magnitude and direction of the target resultant force, ensuring the uniqueness of the direction and the accuracy of the magnitude of the resultant force.

[0063] Step S4: Drive the electric cylinder. The dynamic controller 11 sends output commands to the X-axis electric cylinder and the Y-axis electric cylinder respectively, driving the electric cylinder 7 to output thrust or pull force according to the target output force value.

[0064] Step S5: Real-time Feedback and Closed-Loop Correction. Force sensor 8 measures the actual output force of electric cylinder 7 in real time and feeds the signal back to dynamic controller 11. Dynamic controller 11 compares the actual value with the target value and calculates the deviation. If the deviation exceeds the allowable range, it corrects the output force command of electric cylinder 7 using PID or other control algorithms until the deviation converges. This step achieves real-time closed-loop correction, enabling the actual resultant force vector to track the target value in real time. Even under rapidly changing operating conditions such as frequency sweep or random spectrum, it ensures that the loading error remains within the allowable range (e.g., ±1% or ±5N). It automatically compensates for long-term errors caused by factors such as electric cylinder wear, temperature drift, and installation gaps.

[0065] Step S6: Direction and Magnitude Adjustment. During the experiment, the direction of the resultant force can be continuously adjusted within the range of 0° to 360° by adjusting the ratio of the output values ​​of the two electric cylinders 7; the magnitude of the resultant force can be precisely adjusted by simultaneously adjusting the output values ​​of the two electric cylinders 7. This step achieves continuous adjustment in any direction from 0° to 360°, with a stepless adjustment process, avoiding shocks and abrupt changes during direction switching; at the same time, it achieves continuous and precise adjustment of the magnitude of the resultant force, with the adjustment range limited only by the rated output of the electric cylinders.

[0066] Step S7: Loading Mode Selection. Based on the experimental requirements, select either the constant force static loading mode, the frequency-sweeping sine wave dynamic loading mode, or the random spectrum load dynamic loading mode. In dynamic loading mode, the loading frequency can be programmed within the range of 0 to 10 Hz, and the frequency sweep pattern can be linear or logarithmic. If the random spectrum mode is selected, a random load spectrum is generated based on the lateral force data collected from the actual line, achieving load reproduction from the line to the laboratory.

[0067] Step S8: Linkage Analysis with the Test Bench. The dynamic controller 11 communicates with the main control system of the damper durability test bench, synchronously acquiring force data of the axial piston movement of the damper 15, and combining it with the lateral force data fed back by the force sensor 8 to generate a dynamometer diagram reflecting the influence of lateral force on the damping characteristics of the damper 15. This dynamometer diagram can intuitively display how the damping force-displacement curve of the damper changes when lateral forces of different directions, magnitudes, and frequencies are applied. It can quantitatively analyze phenomena such as damping force attenuation, hysteresis loop area change, and dynamometer diagram distortion caused by lateral force.

[0068] Step S9: Synchronous loading. While the damper 15 is subjected to axial piston movement, the dynamic controller 11 controls the lateral force loading device to synchronously apply a preset dynamic lateral force spectrum, thereby realizing the coordinated simulation of axial movement and lateral load.

[0069] Step S10: Data recording and analysis. The dynamic controller 11 records the data from the force sensor 8 in real time and merges it with the axial force data from the durability test bench to generate a comprehensive dynamometer diagram, which is used to analyze the performance of the vibration damper 15 under combined loads.

[0070] The working principle of the multi-degree-of-freedom dynamic lateral force loading device for the vibration damper durability test bench of this application is as follows: The base frame 1 is mounted on the crossbeam 14 of the durability test bench via guide rail fixing seats 2, and its position can be adjusted by sliding along the axial direction. Two orthogonally arranged electric cylinders 7 are respectively connected to the actuator mounting seats 5 of the base frame 1 via hinges 12, and the other end is connected to the damper mounting fixture 9 via force sensors 8. The two sensor fixing seats 10 on the damper mounting fixture 9 are arranged orthogonally at 90° to ensure that the forces applied by the two electric cylinders 7 form an orthogonal force system on the damper 15.

[0071] The dynamic controller 11 receives the target resultant force vector (magnitude F and direction angle θ) set by the operator, and calculates the target output force values ​​of the two electric cylinders 7 according to the vector decomposition formulas Fx=F·cosθ and Fy=F·sinθ. Then, the dynamic controller 11 drives the two electric cylinders 7 to output Fx and Fy respectively. The two forces combine into a resultant force F on the damper mounting fixture 9. The direction of this resultant force is consistent with the target direction, and the magnitude is consistent with the target force value.

[0072] During the loading process, two force sensors 8 detect the actual output force of the electric cylinder 7 in real time and feed the signal back to the dynamic controller 11. The dynamic controller 11 compares the actual value with the target value and corrects the output force command of the electric cylinder 7 through a closed-loop control algorithm (such as PID) so that the actual resultant force vector always tracks the target value.

[0073] The dynamic controller 11 supports multiple loading modes: constant force mode outputs a constant lateral force; frequency sweep mode outputs a sinusoidal lateral force with continuously varying frequency; and random spectrum mode outputs a random lateral force based on actual road data. The loading frequency can reach 0~10Hz.

[0074] This device can communicate with the main control system of the durability testing bench to achieve coordinated control of axial motion and lateral load. During the test, the dynamic controller 11 generates a comprehensive dynamometer diagram, which visually demonstrates the influence of lateral force on the damping characteristics of the shock absorber.

[0075] Based on the above principles, this device enables the application of lateral force to the vibration damper at any angle, size, and programmable dynamic frequency within a 360° plane, solving the problems of single lateral force direction, inability to be dynamically programmed, and low frequency in existing technologies.

[0076] The multi-degree-of-freedom dynamic lateral force loading device for shock absorber durability testing provided in this application has a simple structure and is easy to install. It can be flexibly adapted to existing testing benches and can accurately simulate the multi-angle dynamic lateral loads borne by the shock absorber during vehicle operation, significantly improving the authenticity and effectiveness of durability testing, and has good industrial practical value.

[0077] The above description is merely a preferred embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A multi-degree-of-freedom dynamic lateral force loading device applied to a shock absorber durability test bench, characterized in that, include: The base frame (1) is used for mounting to the vibration damper durability test bench; The orthogonal actuation system includes two electric cylinders (7) arranged in an orthogonal direction. One end of each electric cylinder (7) is connected to the base frame (1) by a hinge, and the other end is connected to a damper mounting fixture (9) through a force sensor (8). The damper mounting fixture (9) is used to fix the damper (15) to be tested on the outer periphery. The dynamic controller (11) is electrically connected to the two electric cylinders (7) and the two force sensors (8) respectively. It is used to receive the real-time force signal fed back by the force sensors (8) and, based on the magnitude and direction of the preset resultant force vector target value, calculate and generate the output command of each of the two electric cylinders (7) according to the vector decomposition algorithm, so as to apply a dynamic lateral force with continuously adjustable direction and programmable frequency to the damper (15) in the orthogonal plane.

2. The apparatus of claim 1, wherein, The base frame (1) includes multiple guide rail fixing seats (2), which are slidably mounted on the crossbeam (14) of the damper durability test bench and fixed by locking members to adjust the position of the lateral force applied on the damper (15).

3. The apparatus of claim 2, wherein, The guide rail fixing seat (2) has a clamping structure that is adapted to the cross-sectional shape of the crossbeam (14) of the vibration damper durability test bench. The size of the clamping structure can be customized according to the cross-sectional size of the crossbeam (14) to avoid interference with the existing structure of the vibration damper durability test bench.

4. The apparatus according to claim 1, characterized in that, The base frame (1) includes 4 longitudinal beams (3), 2 transverse beams (4) and 2 actuator mounting seats (5). The actuator mounting seats (5) are respectively provided at both ends of the transverse beams (4). The longitudinal beams (3) and transverse beams (4) are detachably assembled by bolts (13).

5. The apparatus according to claim 1, characterized in that, The damper mounting fixture (9) is provided with two sensor mounting seats (10) arranged orthogonally at 90°. The upper end face of each sensor mounting seat (10) is fixed to the force sensor (8), and the electric cylinder (7) is fixed to the upper end face of the force sensor (8). The damper mounting fixture (9) and the force sensor (8) are detachably threaded. The damper mounting fixture (9) includes a replaceable sleeve to adapt to dampers (15) of different diameters.

6. A vibration damper durability testing bench, characterized in that, include: The test bench base is equipped with an axial actuation system for driving the piston of the damper (15) to perform axial reciprocating motion; The multi-degree-of-freedom dynamic lateral force loading device as described in any one of claims 1 to 5 is installed on the crossbeam (14) of the test bench base; and The main controller is communicatively connected to the axial actuation system and the dynamic controller (11) and is used to coordinate the timing of axial motion and lateral loading.

7. A method for controlling multi-degree-of-freedom dynamic lateral force loading using the device described in any one of claims 1 to 5, characterized in that, Includes the following steps: Input the magnitude and direction of the target resultant force vector into the dynamic controller (11); The dynamic controller (11) generates output commands for two orthogonal electric cylinders (7) based on the resultant force vector of the target; The force sensor (8) provides real-time feedback on the actual output force, and the dynamic controller (11) corrects the output force command based on the feedback value. While the damper (15) is subjected to axial piston movement, a preset lateral force is applied simultaneously.

8. The method according to claim 7, characterized in that, The dynamic controller (11) calculates and generates the output force command by decomposing the target resultant force vector into two orthogonal component forces, the magnitudes of which are determined by multiplying the magnitude of the target resultant force vector by the trigonometric function value of the corresponding direction angle.

9. The method according to claim 8, characterized in that, By adjusting the ratio of the output values ​​of the two electric cylinders (7), the direction of the resultant force can be continuously adjusted within the range of 0° to 360°.

10. The method according to claim 8, characterized in that, By synchronously adjusting the output values ​​of the two electric cylinders (7), the magnitude of the resultant force can be precisely adjusted.

11. The method according to claim 7, characterized in that, The dynamic controller (11) supports constant force static loading mode, frequency sweep sine wave dynamic loading mode and random spectrum load dynamic loading mode.

12. The method according to claim 11, characterized in that, The frequency range of the sweeping sine wave dynamic loading mode is 0 to 10 Hz, and the sweeping pattern is linear or logarithmic.

13. The method according to claim 11, characterized in that, The random spectrum load dynamic loading mode generates a random load spectrum based on lateral force data collected from actual roads.

14. The method according to claim 7, characterized in that, Also includes: The dynamic controller (11) communicates with the main control system of the damper durability test bench, synchronously collects the force data of the axial piston movement of the damper (15), and combines the lateral force data fed back by the force sensor (8) to generate a dynamometer diagram reflecting the influence of the lateral force on the damping characteristics of the damper (15).

15. The method according to claim 7, characterized in that, The steps of the dynamic controller (11) to perform closed-loop control include: receiving the target resultant force vector input by the operator, generating the initial commands of the two electric cylinders (7) according to the vector decomposition algorithm, reading the feedback value of the force sensor (8) in real time during the operation of the electric cylinders (7), comparing it with the target value, and correcting the output command.

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