Multi-bench parallel pushing type multi-degree-of-freedom vibration test system and method

Abstract

The invention discloses a multi-bench parallel pushing type multi-degree-of-freedom vibration test system and method, and belongs to the field of vibration tests. The system comprises a master control unit, a sensor network and four vibration table single systems in a 2 * 2 rectangular array, wherein each single system comprises a working table, three vibration generators, three double-spherical hinge series decoupling devices and a power amplifier. Z-direction excitation is achieved through the two vertical vibration generators, Y-direction excitation is achieved through the horizontal vibration generator, and multi-degree-of-freedom motion constraint is released through the double-spherical-hinge series decoupling device. And the master control unit adopts a closed-loop cooperative control method based on the feedback of the sensor: comparing the actual excitation force with a preset thrust target value, calibrating the linear relationship between the output force and the proportionality coefficient of the driving signal through a two-point linear formula, inversely solving and correcting the driving signal, and compensating the individual difference, thereby realizing the high-precision synchronization of the 12 vibration generators. The system can reproduce five-degree-of-freedom coupling vibration of a large-span test piece, and is suitable for simulation of a transportation environment of a concrete precast beam more than 20 meters.

Description

Technical Field

[0001] This invention belongs to the field of vibration testing, specifically relating to a multi-degree-of-freedom vibration testing system and method with multiple units pushed in parallel, which can realize multi-degree-of-freedom vibration. Background Technology

[0002] Currently, there are several multi-degree-of-freedom electric vibration testing systems on the market, with worktable sizes typically around 1 meter. For electric vibration tables, the worktable size is usually less than 4 meters. For precast concrete beams that are often 20 meters long, existing extended worktable sizes cannot meet the requirements. To achieve vibration testing of ultra-large specimens, multiple units are usually pushed in parallel. However, most existing multi-unit parallel vibration testing systems can only achieve translational motion in a single direction, and cannot reproduce the multi-degree-of-freedom vibrations such as lateral swaying and forward / backward bumping that occur during the actual transportation of precast beams.

[0003] To address the vibration problem of large-sized specimens, the industry has proposed a technical approach of using multiple vibration devices working in parallel. For example, patent document CN114216637B discloses a multi-station synchronous vibration testing device that connects multiple vibration tables to a common fixture to increase the total thrust on large specimens. However, the design intent and implementation of such systems primarily focus on achieving synchronous superposition of excitation forces along a single axis (such as the X, Y, or Z axis), and their motion output is essentially a single-degree-of-freedom translation. It is difficult to reproduce the complex multi-degree-of-freedom coupled vibrations experienced by precast beams during actual transportation, such as the synthesis of movements like lateral swaying (Y-axis), vertical swaying (Z-axis), side rolling (around the X-axis), nodding (around the Y-axis), and head shaking (around the Z-axis).

[0004] Achieving high-precision coordination among multiple vibration devices is the core challenge of parallel-push technology. Some existing control methods, such as the "Control Method for Multi-Voscillating Table Parallel-Push Single-Axis Vibration Test" disclosed in patent document CN112444367B, focus on achieving signal equalization and synchronous control of multiple vibration tables under single-axis random vibration excitation through algorithms. While this method solves the synchronization problem of single-axis parallel-push, its control model and objectives are not extended to the coordinated generation and precise control of multi-degree-of-freedom, multi-axis coupled motion. For test scenarios requiring simulation of complex relative motion between the support frame and the beam (such as out-of-phase vibration of different support frames), existing control strategies lack corresponding modeling and control architectures.

[0005] In multi-degree-of-freedom vibration systems, when the worktable needs to achieve large-amplitude translation and rotation, the transmission mechanism connecting the vibration generator and the worktable faces problems of motion interference and internal force coupling. Existing conventional rigid connections or simple hinged methods are difficult to effectively release parasitic constraints generated by multi-degree-of-freedom motion while ensuring the transmission of excitation force, thus leading to motion distortion, additional stress, and even equipment damage.

[0006] In summary, the current technology has the following obvious gaps: there is a lack of a comprehensive vibration testing system that can simultaneously meet the requirements of installing ultra-large specimens, reproducing multi-degree-of-freedom coupled vibrations, achieving high-precision coordinated motion control of multiple exciters, and equipped with a large displacement motion decoupling mechanism. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a multi-stage parallel-push multi-degree-of-freedom vibration testing system. This system can accurately generate five-degree-of-freedom (Y-axis translation, Z-axis translation, rotation about the X-axis, rotation about the Y-axis, and rotation about the Z-axis) coupled vibrations of large-span specimens. It effectively solves the technical bottlenecks of insufficient platform size in existing single-stage systems and the limitation of traditional multi-stage parallel-push systems to single-axis translation. It is particularly suitable for simulating the real-world operating environment of large specimens exceeding 20 meters in length, such as precast concrete beams.

[0008] To achieve the above-mentioned technical objectives, the present invention employs the following technical means:

[0009] A multi-degree-of-freedom vibration testing system with multiple units pushed in parallel includes a central control unit, a sensor network, and four identical vibration table systems.

[0010] The four vibration table single systems form a 2×2 rectangular array; wherein, two vibration table single systems located in the same column form a dual system;

[0011] Each vibration table single system includes: a worktable, a first vibration generator, a second vibration generator, a third vibration generator, three double ball joint series decoupling devices, and a power amplifier to drive the three vibration generators;

[0012] The first and second vibration generators are installed vertically with their excitation force direction parallel to the Z-axis; the third vibration generator is installed horizontally with its excitation force direction parallel to the Y-axis; the main control unit generates and outputs control signals to each power amplifier, and receives the output feedback signals of each vibration generator through the sensor network. Based on the comparison between the output feedback signals and the preset thrust target value, the main control unit corrects the drive signal proportional coefficient of the vibration generator with abnormal output according to the linear relationship between the output force and the drive signal proportional coefficient pre-calibrated in the actual debugging, in order to compensate for the output deviation caused by individual differences, so as to achieve high-precision coordination of all vibration generators in terms of excitation force amplitude and phase, and enable the overall specimen installed on the four worktables to achieve multi-degree-of-freedom vibration.

[0013] Furthermore, the decoupling device is a double ball joint series structure, which includes two hydraulic ball joints connected in sequence. The housings of the two hydraulic ball joints are fixedly connected back to back by flanges, so that the device is rigid in the axial direction to transmit the excitation force, and flexible in the plane perpendicular to the axis to release displacement.

[0014] Furthermore, in each vibration table system, by controlling the excitation forces of the first vibration generator and the second vibration generator to be in phase, the worktable surface is driven to achieve Z-axis translation; by controlling the excitation forces of the first vibration generator and the second vibration generator to be out of phase, the worktable surface is driven to achieve X-axis rotation; and by controlling the excitation force of the third vibration generator, the worktable surface is driven to achieve Y-axis translation.

[0015] Furthermore, it also includes a load-bearing support system, which is located under each work surface and is equipped with support airbags for providing cushioning and posture adjustment, as well as safety protection devices to prevent the work surface from tipping over.

[0016] Furthermore, each vibration table system also includes a clamp disposed on the worktable surface, the clamp being used for fixed connection with the component to be tested.

[0017] Furthermore, each of the vibration table single systems is also extended with a fourth vibration generator, which is arranged along the X-axis and connected to the worktable surface through a decoupling device. This fourth vibration generator is used to drive the worktable surface to achieve X-axis translation, thereby extending the system into a six-degree-of-freedom vibration test system.

[0018] Furthermore, the multi-degree-of-freedom vibration includes Y-axis translation, Z-axis translation, rotation about the X-axis, rotation about the Y-axis, and rotation about the Z-axis; wherein:

[0019] The Y-axis translation is achieved by controlling the third vibration generator in the four single systems to move synchronously in the same direction;

[0020] The Z-axis translation is achieved by controlling the first and second vibration generators in the four single systems to move synchronously in the same direction.

[0021] The rotation around the X-axis is achieved by controlling the first and second vibration generators in each single system to vibrate in opposite directions; the rotation around the Y-axis is achieved by controlling the Z-axis vibration generators of the two single systems in the same dual system to output different magnitudes of excitation force.

[0022] The rotation around the Z-axis is achieved by controlling the Y-axis vibration generators of two single systems within the same dual system to vibrate in opposite directions.

[0023] Another aspect of the present invention discloses a collaborative control method for the aforementioned multi-unit parallel-push multi-degree-of-freedom vibration testing system, comprising the following steps:

[0024] S01: The main control unit outputs the initial drive signal to the power amplifiers of all vibration generators;

[0025] S02: Real-time acquisition of the actual excitation force output by each vibration generator through a sensor network;

[0026] S03: The main control unit compares the actual excitation force output by each vibration generator with the preset thrust target value to determine whether there is a vibration generator with abnormal output.

[0027] S04: If there is a vibration generator with abnormal output, the drive signal proportional coefficient is recalculated based on the linear relationship between the output force and the drive signal proportional coefficient pre-calibrated in the actual debugging of the vibration generator. The original drive signal proportional coefficient is replaced with the corrected drive signal proportional coefficient to obtain the corrected drive signal and output it to the corresponding power amplifier. Then, return to step S02. If there is no abnormal output, the current drive signal is maintained so that all vibration generators work together.

[0028] Furthermore, in step S03, the specific method for determining whether there is a vibration generator with abnormal output is as follows:

[0029] Calculate the actual excitation force of each vibration generator. Compared with the preset thrust target value relative error ,like If the relative error exceeds a preset threshold, the vibration generator is determined to have an abnormal output. The preset threshold value ranges from 1% to 5%.

[0030] Furthermore, in step S04, the specific method for recalculating the drive signal proportional coefficient is as follows: based on the pre-calibrated linear relationship between the output force and the drive signal proportional coefficient:

[0031] ,

[0032] in:

[0033] : Drive signal proportional coefficient, i.e., drive signal proportional coefficient, 0 < ≤ 1;

[0034] : The actual maximum thrust of the i-th vibration generator;

[0035] The preset thrust target value Substitute this linear relationship, and follow = The inverse kinematics yields the proportional coefficient of the drive signal that makes the output force of the vibration generator equal to the preset thrust target value. , as the corrected driving signal scaling factor;

[0036] The calibration method for the linear relationship is as follows: Before the formal test, the vibration generator is powered on and debugged at least twice, different levels of drive signals are applied, the corresponding actual output force is measured, the coordinate points of the drive signal proportional coefficient and the output force are obtained, and the linear relationship between the actual output force of the vibration generator and the drive signal proportional coefficient is established by substituting them into the two-point linear formula.

[0037] Beneficial effects:

[0038] First, it achieves accurate reproduction of multi-degree-of-freedom vibrations in large-sized specimens:

[0039] This invention utilizes four single-system vibration tables arranged in a 2×2 rectangular array, corresponding one-to-one with the transport support frame positions of large specimens such as precast beams. Each single system contains three vibration generators (two vertical and one horizontal), providing three-degree-of-freedom driving capability. Two single systems in the same row form a dual system, which, through hierarchical coordination control by the central control unit, can ultimately accurately generate five-degree-of-freedom (Y-axis translation, Z-axis translation, rotation about the X-axis, rotation about the Y-axis, and rotation about the Z-axis) coupled vibrations of large-span specimens. This effectively solves the technical bottlenecks of insufficient table size in existing single-systems and the limitation of traditional multi-system parallel systems to achieving only single-axis translation, making it particularly suitable for simulating the real-world operating environment of large specimens exceeding 20 meters in length, such as precast concrete beams.

[0040] Second, a double ball joint series decoupling device is adopted to eliminate motion interference and internal force coupling:

[0041] Each vibration generator is connected to the worktable via a double ball joint series decoupling device. This structure effectively releases the multi-directional constraints generated by the worktable during large displacement movements with multiple degrees of freedom, significantly reduces motion interference and internal stress, ensures efficient and pure transmission of excitation force, thereby improving the fidelity of vibration simulation and protecting the equipment from damage caused by motion coupling.

[0042] Third, an adaptive correction algorithm based on individual transfer coefficient calibration is introduced to achieve high-precision collaborative control: the central control unit receives output feedback from each vibration generator in real time through a sensor network and adaptively corrects the drive signal. Specifically, the actual excitation force is compared with the preset thrust target value. For vibration generators with abnormal output, the corrected drive signal is calculated based on their pre-calibrated input-output transfer coefficient. This method can automatically identify and compensate for output deviations caused by individual differences in vibration generators and power amplifiers, ensuring that the 12 vibration generators maintain strict synchronization of excitation force amplitude and phase under complex multi-degree-of-freedom excitation, greatly improving the control accuracy and experimental repeatability of the multi-unit parallel drive system. The independent method claim further clarifies the closed-loop correction process, forming complete technical protection.

[0043] Fourth, by adding a vibration generator in the X-direction to each single system, it can be flexibly expanded into a six-degree-of-freedom system to adapt to a wider range of testing needs.

[0044] Fifth, it possesses six degrees of freedom expansion capabilities to adapt to a wider range of experimental needs:

[0045] Each single system can be expanded to include a fourth vibration generator arranged along the X-axis and connected to the worktable via a double ball joint series decoupling device. This allows the system to be flexibly expanded into a six-degree-of-freedom vibration testing system to meet a wider range of testing needs, demonstrating the forward-looking and scalable nature of the technical solution.

[0046] Sixth, this invention provides a hierarchical coordinated control logic to synthesize simple excitation units into complex multi-degree-of-freedom motion: Through a hierarchical control logic of "single-system control of basic three degrees of freedom and dual-system coordinated synthesis of five degrees of freedom," this invention provides a core control method for synthesizing the output of simple excitation units into complex multi-degree-of-freedom vibrations with high precision and structure. This control logic is clear and hierarchical, providing a reliable technical path for the engineering implementation of multi-unit parallel systems. Attached Figure Description

[0047] Figure 1 It is a top view of a single system in a multi-stage parallel-push multi-degree-of-freedom vibration system;

[0048] Figure 2 It is a front view of a single system in a multi-stage parallel-push multi-degree-of-freedom vibration system;

[0049] Figure 3 This is a front view of a dual-system structure in a multi-stage parallel-push multi-degree-of-freedom vibration system.

[0050] Figure 4 This is a top view of a dual-system structure in a multi-stage parallel-push multi-degree-of-freedom vibration system;

[0051] Figure 5 This is a schematic diagram of the overall vibration system structure of a multi-unit parallel-push multi-degree-of-freedom vibration system;

[0052] Figure 6 This is a schematic diagram of the displacement of a single ball joint as a decoupling device;

[0053] Figure 7 This is a displacement diagram of a double ball joint series as a decoupling device;

[0054] Figure 8 This is a schematic diagram of the rotation of the worktable in a single system;

[0055] Figure 9 This is a schematic diagram of the dual-system worktable rotation;

[0056] Figure 10 This is a schematic diagram of the rotation of the worktable surface of the overall vibration system;

[0057] Figure 11 It is a single-system X-axis translational motion;

[0058] Figure 12 This is a control flowchart for a multi-unit parallel-push multi-degree-of-freedom vibration system.

[0059] Among them, 1 is a single system, 1.1 is a vibration generator, 1.2 is a decoupling device, 1.3 is a clamp, 1.4 is a base, 1.5 is a load-bearing support system, 1.6 is a support airbag, 1.7 is a worktable, 1.8 is a safety protection device, 2 is a support frame, 2.1 is a front support frame, 2.2 is a rear support frame, 3 is a precast beam, r is the center distance between the two spherical bodies at both ends of the ball joint, and θ is the yaw angle. Detailed Implementation

[0060] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0061] In this application, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0062] This invention proposes a multi-stage, parallel-push-type multi-degree-of-freedom vibration testing system. The key technology of this system lies in:

[0063] 1. Decoupling of large displacement motions on each worktable; 2. Multi-degree-of-freedom vibration control strategy for large-span specimens; 3. High-precision collaborative control of multiple vibration generators.

[0064] I. System Overall Architecture and Hardware Composition:

[0065] like Figures 1-6 As shown, the multi-stage parallel-pushing multi-degree-of-freedom vibration test system of the present invention is a total system composed of four identical vibration table single systems.

[0066] System Layout: The four shaking table single systems are arranged in a 2x2 rectangular array. This layout strictly corresponds to the position of the precast beam transport support frame. Specifically, two shaking table single systems located in the same column (along the length of the precast beam) constitute a "dual system" to simulate a set of support frames. Single System Structure: As shown Figure 1 As shown, each shaking table system is a functionally independent basic unit, mainly including the following components:

[0067] Workbench 1.7: A local structure used to install and fix the specimen by means of clamp 1.3.

[0068] Vibration Generator 1.1: Each single system is equipped with three units. Their installation orientation is specifically designed: two units (denoted as the first and second vibration generators) are installed vertically (Z-axis) with their excitation force direction parallel to the Z-axis; the third unit is installed horizontally (Y-axis) with its excitation force direction parallel to the Y-axis.

[0069] Decoupling device 1.2: Three sets in total, connected between the output terminals of the three vibration generators 1.1 and the worktable 1.7 respectively. For their specific layout in a single system, please refer to [reference needed]. Figure 1 This decoupling device employs a double-ball-joint series structure, consisting of two hydraulic ball joints connected sequentially. The housings of the two hydraulic ball joints are fixedly connected back-to-back via flanges, making the device axially rigid to transmit excitation force and flexible in a plane perpendicular to the axis to release displacement. This structure is one of the key innovations, allowing the worktable to effectively release motion constraints from the vibration generator during multi-degree-of-freedom large displacement movements, avoiding the generation of parasitic internal forces, and ensuring excitation force transmission efficiency and motion fidelity.

[0070] The load-bearing support system 1.5 is located below the worktable 1.7 and is used to bear most of the static load of the specimen. Support airbags 1.6 are installed on it to provide cushioning and assist in fine-tuning the posture; a safety protection device 1.8 is also provided to prevent the worktable from tipping over in extreme situations.

[0071] Power amplifier (not shown separately in the figure): used to receive control signals and drive the corresponding vibration generator.

[0072] Base 1.4: Provides a stable mounting foundation for the entire single system.

[0073] Control and Sensing: The system has a central control unit (or main control unit), which connects all power amplifiers via a cable network to output drive signals. Simultaneously, force sensors are placed on each vibration generator, forming a sensor network to measure and feed back the actual output excitation force to the central control unit in real time, thus forming a closed-loop control circuit.

[0074] II. Implementation of Multi-Degree-of-Freedom Vibration Control Strategies:

[0075] The core of this invention lies in using a hierarchical control strategy to transform simple single-point excitation into complex overall multi-degree-of-freedom motion.

[0076] Single-system degree of freedom realization (3 degrees of freedom):

[0077] Y-axis translation: Controlling the output of the third vibration generator (Y-axis) can drive the worktable to move horizontally along the Y-axis.

[0078] Z-axis translation: By controlling the first vibration generator and the second vibration generator (Z-axis) to output excitation forces of the same phase and magnitude, the worktable can be driven to move vertically along the Z-axis.

[0079] Rotation around the X-axis: Control the first vibration generator and the second vibration generator to output excitation forces with opposite phase (such as a phase difference of π) to form a couple, which can drive the worktable to rotate around the X-axis.

[0080] Achieving dual-system degrees of freedom (5 degrees of freedom):

[0081] A dual system comprises two parallel single systems (e.g.) Figure 5 (Single systems A and B in the example). Based on the three degrees of freedom of the single system, by coordinating the outputs of the corresponding vibration generators in the two single systems, two additional rotational degrees of freedom can be generated:

[0082] Rotation around the Y-axis (nodding): This causes the two single-system Z-axis vibration generators (A1, A2 and B1, B2) to output forces of different magnitudes, forming a torque around the Y-axis.

[0083] Rotation about the Z-axis (head shaking): This causes the Y-axis vibration generators (A3 and B3) of the two single systems to output forces in opposite directions, forming a torque about the Z-axis. Therefore, a dual system can achieve translation in the Y and Z axes, and rotation about the X, Y, and Z axes, for a total of five degrees of freedom.

[0084] Total system degrees of freedom realized:

[0085] The entire system consists of two dual systems (simulating the front and rear beam support frames). The main control unit implements unified or differentiated coordinated control of the two dual systems according to the experimental requirements. For example, to achieve pure Y-axis translation, it is necessary to control all Y-axis vibration generators (A3, B3, C3, D3) of the four single systems to move synchronously in the same direction. Table 1 details the required combinations of excitation force directions for each vibration generator (A1~D3) to achieve "local multi-degree-of-freedom vibration" and "overall multi-degree-of-freedom vibration" (arrows indicate whether the directions are consistent). By programming the control logic in Table 1, the various vibration modes experienced by the beam during transportation can be accurately reproduced. Table 1 Multi-degree-of-freedom control strategy

[0086] Note: The arrows in the table only indicate whether the directions of each vibration generator are consistent.

[0087] III. Implementation of High-Precision Collaborative Control Methods

[0088] The multi-stage parallel-push multi-degree-of-freedom vibration system comprises 12 vibration generators. High-precision coordinated control among these generators is crucial for accurate testing. During testing, it is essential to ensure that the excitation force amplitudes output by each generator are consistent, and that the phase difference is consistent or zero. Taking the superimposed Y-axis translational vibration around the X-axis of the overall multi-degree-of-freedom vibration as an example, the following conditions must be met: the excitation force amplitudes of all 12 generators are consistent; the directions of A1, B1, C1, and D1 are consistent (zero phase difference); the directions of A2, B2, C2, and D2 are consistent, and opposite to the directions of A3, B3, C3, and D3 (phase difference of π / 2).

[0089] During actual operation, although the input signals from the main control unit are consistent, the outputs of each vibration generator exhibit certain deviations due to individual differences. Therefore, the input signals of each vibration generator must be corrected to ensure high-precision coordinated control of the system. The control flowchart is as follows: Figure 12 As shown, the central control unit inputs the same initial signal to the power amplifier, which amplifies the electrical signal and inputs it to each vibration generator. The sensors feed back the collected output force to the central control unit. The central control unit's built-in program compares each output force with a preset thrust target value, identifies abnormal values ​​in the output force, and corrects the initial signal. The corrected value is then input back to the power amplifier to obtain a new output force, thus completing high-precision coordinated control between the vibration generators.

[0090] Specifically, outlier detection:

[0091] Rated maximum thrust of a single vibration generator , It represents the magnetic flux density. This is the effective length of the moving coil winding. The maximum current of the moving coil is preset to a target thrust value of [value missing]. Let the drive signal scaling factor be... ( Theoretically, all 12 vibration generators should have the same maximum thrust Fmax. However, due to individual differences in the vibration generators and power amplifiers, their maximum thrust values ​​will vary. Therefore, when the same proportional coefficient is applied to the input drive signal, the actual output force will differ. There will also be some differences for (i=1~12), This is the actual output force of the i-th vibration generator. Output force error. ,when (Not necessarily 1%, can be adjusted according to the required test accuracy) the corresponding output force of the vibration generator. It is considered an outlier.

[0092] Outlier correction:

[0093] The actual output force of the vibration generator Before the formal test, two power-on debugging sessions were conducted, and the coordinates of two points were obtained for each vibration generator. From this, the actual maximum thrust value of each vibration generator can be calculated.

[0094] The first input is a sine sweep signal on the order of 50%, and the second input is a sine sweep signal on the order of 80% (the magnitude is adjusted by controlling the drive voltage).

[0095] The measured output is the acceleration response measured by the accelerometer, and then the actual output force is indirectly obtained through F=ma (m is the mass of the moving coil + the mass of the load).

[0096] The coordinate refers to the ratio of the drive signal proportionality coefficient to the output force coordinate, for example (50%). ), (80%) ). (50%, ), (80%) Substituting into the two-point line formula, we get... The linear relationship.

[0097] The output force of the vibration generator can then be obtained. satisfy of value.

[0098] Iterative loop: The corrected signal is output again, new feedback force is collected, and the judgment and correction steps are repeated until the output force error of all vibration generators is within the allowable range, thereby achieving high-precision coordination of the system.

[0099] If the test requires translation in the X-axis (forward direction), a fourth vibration generator equipped with a decoupling device can be added to each single system in the X-axis direction of the worktable surface (e.g., ...). Figure 11 As shown in the figure, this extends the system to achieve six degrees of freedom vibration.

[0100] Any adaptive changes made according to actual needs are within the scope of protection of this invention.

[0101] It should be noted that, for those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered as exemplary and non-limiting in all respects, and the scope of the present invention is defined by the appended claims rather than the foregoing description. Therefore, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention; at the same time, for those skilled in the art, there will be changes in specific implementation methods and application scope based on the ideas of the present invention. In summary, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A multi-unit parallel-push multi-degree-of-freedom vibration testing system, characterized in that, It includes a central control unit, a sensor network, and four identical shaking table systems; The four vibration table single systems form a 2×2 rectangular array; wherein, two vibration table single systems located in the same column form a dual system; Each vibration table single system includes: a worktable, a first vibration generator, a second vibration generator, a third vibration generator, three double ball joint series decoupling devices, and a power amplifier to drive the three vibration generators; The first and second vibration generators are installed vertically with their excitation force direction parallel to the Z-axis; the third vibration generator is installed horizontally with its excitation force direction parallel to the Y-axis. The main control unit generates and outputs control signals to each power amplifier and receives output feedback signals from each vibration generator through the sensor network. Based on the comparison between the output feedback signal and the preset thrust target value, the main control unit corrects the drive signal proportional coefficient of the vibration generator with abnormal output according to the linear relationship between the output force and the drive signal proportional coefficient pre-calibrated in the actual debugging. This is to compensate for the output deviation caused by individual differences, achieve high-precision coordination of all vibration generators in terms of excitation force amplitude and phase, and enable the overall specimen mounted on the four worktables to achieve multi-degree-of-freedom vibration.

2. The multi-unit parallel-push multi-degree-of-freedom vibration testing system according to claim 1, characterized in that, The decoupling device is a double ball joint series structure, which includes two hydraulic ball joints connected in sequence. The housings of the two hydraulic ball joints are fixedly connected back to back by flanges, so that the decoupling device is rigid in the axial direction to transmit the excitation force, and flexible in the plane perpendicular to the axis to release the displacement.

3. The multi-unit parallel-push multi-degree-of-freedom vibration testing system according to claim 1, characterized in that, In each vibration table system, by controlling the excitation forces of the first vibration generator and the second vibration generator to be in phase, the worktable surface is driven to achieve Z-axis translation; by controlling the excitation forces of the first vibration generator and the second vibration generator to be out of phase, the worktable surface is driven to achieve X-axis rotation; and by controlling the excitation force of the third vibration generator, the worktable surface is driven to achieve Y-axis translation.

4. The multi-unit parallel-push multi-degree-of-freedom vibration testing system according to claim 1, characterized in that, It also includes a load-bearing support system, which is located under each work surface and is equipped with support airbags for providing cushioning and posture adjustment, as well as safety protection devices to prevent the work surface from tipping over.

5. The multi-unit parallel-push multi-degree-of-freedom vibration testing system according to claim 1, characterized in that, Each vibration table system also includes a clamp disposed on the worktable surface, the clamp being used for fixed connection with the component to be tested.

6. The multi-unit parallel-push multi-degree-of-freedom vibration testing system according to claim 1, characterized in that, Each of the vibration table systems is further extended with a fourth vibration generator, which is arranged along the X-axis and connected to the worktable surface through a decoupling device. This fourth vibration generator is used to drive the worktable surface to achieve X-axis translation, thus extending the system into a six-degree-of-freedom vibration test system.

7. The multi-unit parallel-push multi-degree-of-freedom vibration testing system according to claim 1, characterized in that, The multi-degree-of-freedom vibration includes Y-axis translation, Z-axis translation, rotation about the X-axis, rotation about the Y-axis, and rotation about the Z-axis; wherein: The Y-axis translation is achieved by controlling the third vibration generator in the four single systems to move synchronously in the same direction; The Z-axis translation is achieved by controlling the first and second vibration generators in the four single systems to move synchronously in the same direction. The rotation around the X-axis is achieved by controlling the first and second vibration generators in each individual system to vibrate in the opposite direction. The rotation around the Y-axis is achieved by controlling the Z-axis vibration generators of two single systems within the same dual system to output different magnitudes of excitation force; The rotation around the Z-axis is achieved by controlling the Y-axis vibration generators of two single systems within the same dual system to vibrate in opposite directions.

8. The collaborative control method for a multi-unit parallel-push multi-degree-of-freedom vibration testing system according to any one of claims 1 to 7, characterized in that, Includes the following steps: S01: The main control unit outputs the initial drive signal to the power amplifiers of all vibration generators; S02: Real-time acquisition of the actual excitation force output by each vibration generator through a sensor network; S03: The main control unit compares the actual excitation force output by each vibration generator with the preset thrust target value to determine whether there is a vibration generator with abnormal output. S04: If there is a vibration generator with abnormal output, the drive signal proportional coefficient is recalculated based on the linear relationship between the output force and the drive signal proportional coefficient pre-calibrated in the actual debugging of the vibration generator. The original drive signal proportional coefficient is replaced with the corrected drive signal proportional coefficient to obtain the corrected drive signal and output it to the corresponding power amplifier. Then, return to step S02. If there is no abnormal output, the current drive signal is maintained so that all vibration generators work together.

9. The collaborative control method for a multi-unit parallel-push multi-degree-of-freedom vibration testing system according to claim 8, characterized in that, In step S03, the specific method for determining whether there is a vibration generator with abnormal output is as follows: Calculate the actual excitation force of each vibration generator. Compared with the preset thrust target value relative error ,like If the relative error exceeds a preset threshold, the vibration generator is determined to have an abnormal output. The preset threshold value ranges from 1% to 5%.

10. The collaborative control method for a multi-unit parallel-push multi-degree-of-freedom vibration testing system according to claim 8, characterized in that, In step S04, the specific method for recalculating the drive signal proportional coefficient is as follows: based on the pre-calibrated linear relationship between the output force and the drive signal proportional coefficient: ， in: : Drive signal proportional coefficient, 0 < ≤ 1; : The actual maximum thrust of the i-th vibration generator; The preset thrust target value Substitute this linear relationship, and follow = The inverse kinematics yields the proportional coefficient of the drive signal that makes the output force of the vibration generator equal to the preset thrust target value. , as the corrected driving signal scaling factor; The calibration method for the linear relationship is as follows: Before the formal test, the vibration generator is powered on and debugged at least twice, different levels of drive signals are applied, the corresponding actual output force is measured, the coordinate points of the drive signal proportional coefficient and the output force are obtained, and the linear relationship between the actual output force of the vibration generator and the drive signal proportional coefficient is established by substituting them into the two-point straight line formula.

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