An experimental system and method for semi-active control of cantilever beam vibration with tip mass

Abstract

The present application belongs to the technical field of vibration control, and aims to solve the problem that the existing cantilever beam vibration test bench does not consider the influence of the oil cylinder and the roller on the dynamic characteristics of the cantilever beam in the design, lacks components for simulating the oil cylinder and the roller, and cannot simulate the vibration of the tunneling equipment when working. A kind of end concentrated mass cantilever beam vibration semi-active control experiment system and method is provided, compared with other cantilever beam vibration test benches, the support member for simulating the influence of the oil cylinder on the vibration is added, and the main frame, the equal cross section beam and the support are connected in a hinged manner, which can better study the dynamic characteristics and semi-active control method of a series of similar mechanisms such as tunneling equipment when working, is simple to operate, can quickly process and analyze various vibration signals, and can be used to verify and compare the effectiveness and practicability of the vibration caused by various tunneling equipment cutting arms when working and the semi-active control algorithm.

Description

Technical Field

[0001] This invention belongs to the field of cantilever beam vibration control technology, specifically relating to an experimental system and method for semi-active control of vibration of a cantilever beam with concentrated end mass. Background Technology

[0002] Coal is the main component of my country's energy structure. As the main equipment for coal mining, coal tunneling machines operate in harsh environments and face complex and variable working conditions. When cutting coal and rock at the mining face, the drum will generate strong vibrations and swings, applying severe impact loads to the cutting arm and even the entire tunneling equipment. This can lead to serious damage, failure, or even breakage of key components such as bolts, crossbeams, and rotary tables, seriously affecting the reliability, stability, and safety of the equipment operation.

[0003] Therefore, achieving vibration control of tunneling equipment, especially the cutting arm, is a research direction and challenge that urgently needs to be addressed. The cantilever beam structure is a common mechanical structure, and the cutting arm of tunneling equipment can be simplified into a cantilever beam with concentrated mass at its end. Vibration control experiments on tunneling equipment such as roadheaders, tunneling machines, and continuous mining machines can be conducted by designing a cantilever beam vibration test bench.

[0004] Currently, existing cantilever beam vibration control test benches, such as the technologies and methods provided in patents CN109211502A and CN221125401U, have the following shortcomings:

[0005] 1. Existing tunneling equipment controls the movement of the cutting arm through hydraulic cylinders. The test bench in the aforementioned patent did not consider the influence of the hydraulic cylinder structure on the vibration of the cantilever beam.

[0006] 2. In existing tunneling equipment, the end roller has a large mass, and the mass is not evenly distributed across the entire cantilever beam model. Summary of the Invention

[0007] In order to solve at least one of the above-mentioned technical problems in the prior art, the present invention provides an experimental system and method for semi-active control of vibration of a cantilever beam with concentrated end mass.

[0008] This invention is achieved using the following technical solution: a semi-active control experimental system for the vibration of a cantilever beam with concentrated end mass, comprising a cantilever beam vibration test bench, a dynamic vibration absorber, a vibration exciter, a sensor measurement module, a dynamic signal acquisition module, a power amplifier, a PLC control module, and a terminal;

[0009] The cantilever beam vibration test bench includes a main frame, a constant cross-section beam, a hydraulic cylinder simulated support, and counterweights. The main frame is a scaled-down model of the tunneling equipment body, the constant cross-section beam is a scaled-down model of the tunneling equipment cutting arm structure and is hinged to the main frame, the hydraulic cylinder simulated support is hinged between the main frame and the constant cross-section beam surface, and the position of the constant cross-section beam can be adjusted to the target position by replacing the hydraulic cylinder simulated support. The counterweights are installed on both sides of the main frame and at the end of the constant cross-section beam.

[0010] The dynamic vibration absorber includes a mass block, a magnetorheological damper, an elastic element, and a mounting assembly. By adjusting the mass of the mass block and the stiffness of the elastic element, the natural frequency of the dynamic vibration absorber can be adjusted to be close to the desired control mode frequency. The magnetorheological damper is used for semi-active control of a beam with a uniform cross-section. The dynamic vibration absorber can be set at a preset experimental position on the upper end of the beam with a uniform cross-section through the mounting assembly.

[0011] The excitation point of the vibrator can be connected to a beam with a uniform cross-section or a dynamic vibration absorber to realize modal analysis experiments and semi-active vibration control experiments. The sensors of the sensor measurement module are set at the corresponding test nodes. The dynamic signal acquisition module is used to receive the excitation signal sent by the terminal and the measurement data returned by the sensor measurement module, and can transmit the excitation signal and measurement data to the power amplifier and the terminal respectively. The power amplifier is used to drive the vibrator to excite the cantilever beam vibration test bench. The PLC control module is used to send electrical signals to the dynamic vibration absorber based on the measurement data returned by the sensor measurement module to realize semi-active control.

[0012] Preferably, the main frame is an H-shaped structure, with a constant cross-section beam hinged at the middle frame of the main frame. The counterweights are installed in the reserved holes on the main frame and the constant cross-section beam by bolts, and the number of counterweights can be adjusted. The counterweights are used to simulate the concentrated mass represented by the tunneling equipment drum and to increase the mass of the main frame, so as to reduce the vibration of the main frame when the constant cross-section beam is excited.

[0013] Preferably, the mounting assembly of the dynamic vibration absorber includes a vibration absorber base and a stud. The vibration absorber base is mounted on the beam with a uniform cross-section via the stud. The elastic element includes a guide rail and a compression spring that is movably sleeved outside the guide rail. The guide rail is fixedly inserted into a hole at the upper end of the stud. The mass block is slidably connected to the guide rail and located at the upper end of the compression spring. A linear bearing is installed in the hole corresponding to the guide rail at the mass block. The mass block and the vibration absorber base are connected by a magnetorheological rheostat. The position of the mass block is changed by changing the damping force of the magnetorheological rheostat based on the PLC control module.

[0014] Preferably, the stud is an irregularly shaped stud, and the stud head has two concentric holes from the top down. The two concentric holes are used to install the guide rail and the compression spring, respectively. The side wall of the stud head has a threaded hole on the inward side. The guide rail is locked onto the stud by a screw inserted into the threaded hole.

[0015] Preferably, the sensor measurement module includes an accelerometer, a force sensor, a miniature tensile sensor, and a laser displacement sensor, used to measure acceleration, force conditions, and displacement of the target node during the experiment;

[0016] Accelerometers are installed at equal intervals on the surface of the beam with uniform cross-section or on the mass block; force sensors are installed at the connection between the exciter and the beam with uniform cross-section or at the connection between the exciter and the base of the vibration absorber; miniature tension sensors are installed at the connection between the mass block and the magnetorheological damper; and laser displacement sensors are installed at the end of the beam with uniform cross-section.

[0017] Preferably, the dynamic signal acquisition module includes a dynamic signal acquisition card, a signal source card, and a speed / counter measurement card. The dynamic signal acquisition card is used to acquire sensor signals, the signal source card sends excitation signals to the power amplifier, and the speed / counter measurement card is used for speed or frequency counting. The terminal is used to calculate the modes of the test object and their frequency response curves. The power amplifier is used to adjust the amplitude of the output signal to meet the excitation force required for the experiment.

[0018] This invention also provides an experimental method for semi-active control of vibration of a cantilever beam with concentrated end mass, comprising the following steps:

[0019] S1: Assemble the cantilever beam vibration test bench, select the hydraulic cylinder to simulate the support so that the position of the beam with uniform cross-section is the target position, select the counterweight block with preset weight to simulate the concentrated mass represented by the drum of the tunneling equipment and increase the mass of the main frame; connect the excitation point of the vibrator to the end of the beam with uniform cross-section.

[0020] S2: Accelerometers are placed at equal intervals on the surface of the beam with uniform cross-section, and force sensors are installed at the connection between the exciter and the beam with uniform cross-section.

[0021] S3: Connect the exciter, sensor measurement module, dynamic signal acquisition module, power amplifier, and terminal;

[0022] S4: Start the above experimental setup and excite the end of the beam with uniform cross-section;

[0023] S5: The terminal determines the amplitude and shape of the output signal and adjusts it through the power amplifier (11);

[0024] S6: Calculate and plot the frequency characteristics of the entire end-concentrated mass cantilever beam vibration test bench, identify the natural frequencies and mode shapes of each mode, and denote the experimentally obtained natural frequencies as α. i For i = 1, 2, 3, ..., the frequencies calculated by ANSYS are β. i ,i=1,2,3,…, if Then check and modify the simulation model and experimental model, and repeat the above process until...

[0025] S7: Separate the vibrator from the beam with equal cross-section, connect the vibration absorber base to the vibrator, install an acceleration sensor on the mass block, and install a force sensor at the connection between the vibration absorber base and the vibrator.

[0026] S8: Use a vibrator to excite the dynamic vibration absorber and calculate the natural frequency γ of the dynamic vibration absorber. If i is the modal order for which vibration reduction is to be performed, then repeat step S8 until...

[0027] S9: Separate the vibration absorber base from the vibrator, connect the excitation point of the vibrator to the end of the constant cross-section beam, install the dynamic vibration absorber at the preset position of the constant cross-section beam, install an acceleration sensor on the mass block, install a force sensor at the connection between the vibrator and the constant cross-section beam, install a miniature tensile and compressive sensor at the connection between the magnetorheological damper and the vibration absorber base, distribute acceleration sensors evenly on the constant cross-section beam, and install a laser displacement sensor at the end;

[0028] S10: Excite the end of the beam with uniform cross section, and control the damping force of the magnetorheological damper (6) by the PLC control module to complete the semi-active vibration control.

[0029] S11: Recalculate and plot the frequency characteristics of the system, determine the natural frequencies and mode shapes of each mode, and compare them with the frequency characteristic curves before the addition of the dynamic vibration absorber to verify the control effect of the algorithm.

[0030] Preferably, the vibration direction of the exciter is perpendicular to the upper surface of the beam with a uniform cross-section.

[0031] Compared with the prior art, the beneficial effects of the present invention are:

[0032] This invention designs a corresponding test bench for tunneling equipment. Compared with other cantilever beam vibration test benches, it adds a support component to simulate the vibration effect of the hydraulic cylinder's traction motion and uses a hinged connection to connect the main frame, the equal-section beam, and the support. This allows for better research on the dynamic characteristics and semi-active control methods of tunneling equipment and a series of similar mechanisms during operation.

[0033] The experimental system and method provided by this invention are simple to operate and can quickly process and analyze various vibration signals. They can be used to verify and compare the vibrations caused by the cutting arm of various tunneling equipment during operation, as well as the effectiveness and practicality of the semi-active control algorithm. This provides an efficient and accurate platform for subsequent experimental research on the semi-active control of cantilever equipment. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a perspective view of the cantilever beam vibration test bench provided by the present invention;

[0036] Figure 2 This is a front view of the cantilever beam vibration test bench provided by the present invention;

[0037] Figure 3 This is a right view of the cantilever beam vibration test bench provided by the present invention;

[0038] Figure 4 A top view of the cantilever beam vibration test bench provided by the present invention;

[0039] Figure 5 A schematic diagram of the experimental system for cantilever beam vibration modal analysis provided by the present invention;

[0040] Figure 6 A schematic diagram of the semi-active control experimental system for cantilever beam vibration provided by the present invention;

[0041] Figure 7 The three-view and oblique view of the irregular stud of the dynamic vibration absorber provided by the present invention;

[0042] Figure 8 The experimental flowchart for cantilever beam vibration modal analysis provided by this invention;

[0043] Figure 9 The experimental flowchart for the semi-active control of cantilever beam vibration provided by this invention.

[0044] In the diagram: 1-Main frame; 2-Equal cross-section beam; 3-Hydraulic cylinder simulated support; 4-Counterweight; 5-Mass block; 6-Magnetorheological damper; 7-Elastic element; 8-Vibration absorber base; 9-Stud; 10-Dynamic signal acquisition module; 11-Power amplifier; 12-Vibrator; 13-Sensor measurement module; 14-Terminal; 15-PLC control module. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described 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 implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] It should be noted that the structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should fall within the scope of the technical content disclosed in the present invention. It should be noted that in this specification, relational terms such as "first" and "second" are only used to distinguish one entity from several other entities, and do not necessarily require or imply any actual relationship or order between these entities.

[0047] This invention provides an embodiment:

[0048] like Figures 1 to 9 As shown, a semi-active control experimental system for the vibration of a cantilever beam with concentrated end mass includes a cantilever beam vibration test bench, a dynamic vibration absorber, a vibration exciter 12, a sensor measurement module 13, a dynamic signal acquisition module 10, a power amplifier 11, a PLC control module 15, and a terminal 14.

[0049] The cantilever beam vibration test bench includes a main frame 1, a constant cross-section beam 2, a hydraulic cylinder simulated support 3, and counterweights 4. The main frame 1 is a scaled-down model of the tunneling equipment body, placed horizontally on the ground. The constant cross-section beam 2 is a scaled-down model of the tunneling equipment cutting arm structure and is hinged to the main frame 1. The hydraulic cylinder simulated support 3 is hinged between the main frame 1 and the constant cross-section beam 2. By replacing the hydraulic cylinder simulated support 3, the position of the constant cross-section beam 2 can be adjusted to the target position. The hydraulic cylinder simulated support 3 can be designed with different lengths, widths, and thicknesses, thereby adjusting the position and stress of the constant cross-section beam 2 by changing different supports. The counterweights 4 are installed on both sides of the main frame 1 and at the end of the constant cross-section beam 2.

[0050] The dynamic vibration absorber includes a mass block 5, a magnetorheological damper 6, an elastic element 7, and a mounting assembly. By adjusting the mass of the mass block 5 and the stiffness of the elastic element, the natural frequency of the dynamic vibration absorber can be adjusted to be close to the desired control mode frequency. The magnetorheological damper 6 is used for semi-active control of the beam 2 with uniform cross section. The dynamic vibration absorber can be set at a preset experimental position on the upper end of the beam 2 with uniform cross section through the mounting assembly.

[0051] The excitation point of the vibrator 12 can be connected to the uniform cross-section beam 2 or the dynamic vibration absorber to realize modal analysis experiments and semi-active vibration control experiments; the vibration direction of the vibrator 12 is perpendicular to the upper surface of the uniform cross-section beam 2. The sensors of the sensor measurement module 13 are set at the corresponding test nodes. The dynamic signal acquisition module 10 is used to receive the excitation signal sent by the terminal and the measurement data returned by the sensor measurement module 13, and can transmit the excitation signal and measurement data to the power amplifier 11 and the terminal 14 respectively; the power amplifier 11 is used to drive the vibrator 12 to excite the cantilever beam vibration test bench; the PLC control module 15 is used to send electrical signals to the dynamic vibration absorber based on the measurement data returned by the sensor measurement module 13 to realize semi-active control.

[0052] In this embodiment, the main frame 1 has an H-shaped structure with support parts on both sides and a connecting part in the middle. The support parts have holes on the top for installing and adjusting the number and position of the counterweights 4. The upper surface of the connecting part is designed with four hinges, which are hinged to the constant cross-section beam 2 through pins. Without the hydraulic cylinder simulating support 3, the constant cross-section beam 2 can rotate freely above the horizontal angle with the center of the hinge as the origin. The front surface of the connecting part is designed with two hinges, which are hinged to the hydraulic cylinder simulating support 3. The constant cross-section beam 2 is hinged to the middle frame of the main frame 1. The counterweights 4 are installed with bolts at the reserved holes on the main frame 1 and the constant cross-section beam 2, and the number can be adjusted. The counterweights 4 are used to simulate the concentrated mass represented by the drum of the tunneling equipment and increase the mass of the main frame 1, so as to reduce the vibration of the main frame when the constant cross-section beam 2 is excited, thereby making the whole model closer to the actual working situation of the tunneling equipment.

[0053] The mounting components of the dynamic vibration absorber include a vibration absorber base 8 and a stud 9. The vibration absorber base 8 is mounted on the constant cross-section beam 2 via the stud 9. The elastic element 7 includes a guide rail and a compression spring that is movably sleeved outside the guide rail. The guide rail is fixedly inserted into a hole at the upper end of the stud 9. The mass block 5 is slidably connected to the guide rail and located at the upper end of the compression spring, ensuring that the mass block 5 moves only in the direction perpendicular to the upper surface of the constant cross-section beam 2 during vibration. Preferably, the guide rail surface is smooth and the mass is less than one-third of the mass block. A linear bearing is installed in the hole corresponding to the guide rail at the mass block 5. The linear bearing is used to reduce the friction generated between the elastic element 7 guide rail and the mass block 5 during movement. The mass block 5 and the elastic element 7 are appropriately adjusted and replaced according to the modal analysis results.

[0054] The mass block 5 and the vibration absorber base 8 are connected by a magnetorheological rheostat 6. The output of the magnetorheological rheostat 6 can be controlled by changing the input current value; the larger the current, the greater the damping force. The position of the mass block 5 is changed by changing the damping force of the magnetorheological rheostat 6 based on the PLC control module 15. The stud 9 is an irregular stud, and the stud head has two concentric holes from the top downwards. The two concentric holes are used to install the guide rail and the compression spring, respectively. The side wall of the stud head has a threaded hole on the inward side. The guide rail is locked onto the stud 9 by screws inserted into the threaded holes.

[0055] The sensor measurement module 13 includes an accelerometer, a force sensor, a miniature tension sensor, and a laser displacement sensor, used to measure acceleration, force conditions, and displacement of the target node during the experiment. The accelerometer is installed at equal intervals on the surface of the uniform cross-section beam 2 or at the mass block 5. The force sensor is installed at the connection between the exciter 12 and the uniform cross-section beam 2 or at the connection between the exciter 12 and the vibration absorber base 8. The miniature tension sensor is installed at the connection between the mass block 5 and the magnetorheological damper 6. The laser displacement sensor is installed at the end of the uniform cross-section beam 2.

[0056] The dynamic signal acquisition module 10 includes a dynamic signal acquisition card, a signal source card, and a speed / counter measurement card. The dynamic signal acquisition card is used to acquire sensor signals, the signal source card sends excitation signals to the power amplifier, and the speed / counter measurement card is used for speed or frequency counting. The terminal 14 is used to calculate the modes of the test object and their frequency response curves. The power amplifier 11 is used to adjust the amplitude of the output signal to meet the excitation force required for the experiment.

[0057] A semi-active experimental method for controlling the vibration of a cantilever beam with concentrated end mass includes the following steps:

[0058] S1: Assemble the cantilever beam vibration test bench, select the hydraulic cylinder to simulate the support 3 so that the position of the beam 2 with the constant cross section is the target position, select the counterweight block 4 with the preset weight to simulate the concentrated mass represented by the tunneling equipment drum and increase the mass of the main frame 1; connect the excitation point of the vibrator 12 to the end of the beam 2 with the constant cross section.

[0059] S2: On the central axis of the uniform cross-section beam 2, accelerometers are set at equal intervals on the surface of the uniform cross-section beam 2, and force sensors are installed at the connection between the exciter 12 and the uniform cross-section beam 2.

[0060] S3: Connect the exciter 12, sensor measurement module 13, dynamic signal acquisition module 10, power amplifier 11, and terminal 14;

[0061] S4: Start the above experimental setup and excite the end of beam 2 with uniform cross section;

[0062] S5: Terminal 14 determines the amplitude and shape of the output signal and adjusts it through power amplifier (11);

[0063] S6: Calculate and plot the frequency characteristics of the entire end-concentrated mass cantilever beam vibration test bench, identify the natural frequencies and mode shapes of each mode, and denote the experimentally obtained natural frequencies as α. i For i = 1, 2, 3, ..., the frequencies calculated by ANSYS are β. i ,i=1,2,3,…, if Then check and modify the simulation model and experimental model, and repeat the above process until...

[0064] S7: Separate the vibrator 12 from the beam 2 with equal cross section, and connect the vibration absorber base 8 to the vibrator 12. Install an acceleration sensor on the mass block 5, and install a force sensor at the connection between the vibration absorber base 8 and the vibrator 12.

[0065] S8: Use exciter 12 to excite the dynamic vibration absorber, and calculate the natural frequency γ of the dynamic vibration absorber. If %, and i represents the modal order for which vibration reduction is to be performed, then repeat step S8 until...

[0066] S9: Separate the vibration absorber base 8 from the vibrator 12, connect the excitation point of the vibrator 12 to the end of the constant cross-section beam 2, install the dynamic vibration absorber at the preset position of the constant cross-section beam 2, install an acceleration sensor on the mass block 5, install a force sensor at the connection between the vibrator 12 and the constant cross-section beam 2, install a miniature tensile and compressive sensor at the connection between the magnetorheological damper 6 and the vibration absorber base 8, distribute acceleration sensors evenly on the constant cross-section beam 2, and install a laser displacement sensor at the end;

[0067] S10: Excite the end of the beam 2 with equal cross section. The PLC control module 15 controls the damping force of the magnetorheological damper (6) to complete the semi-active vibration control.

[0068] S11: Recalculate and plot the frequency characteristics of the system, determine the natural frequencies and mode shapes of each mode, and compare them with the frequency characteristic curves before the addition of the dynamic vibration absorber to verify the control effect of the algorithm.

[0069] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A semi-active control experimental system for the vibration of a cantilever beam with concentrated end mass, characterized in that: It includes a cantilever beam vibration test bench, a dynamic vibration absorber, a vibrator (12), a sensor measurement module (13), a dynamic signal acquisition module (10), a power amplifier (11), a PLC control module (15), and a terminal (14). The cantilever beam vibration test bench includes a main frame (1), a beam with equal cross-section (2), a hydraulic cylinder simulation support (3), and a counterweight (4). The main frame (1) is a scaled-down model of the tunneling equipment body. The beam with equal cross-section (2) is a scaled-down cutting arm structure of the tunneling equipment and is hinged to the main frame (1). The hydraulic cylinder simulation support (3) is hinged between the main frame (1) and the beam with equal cross-section (2). The position of the beam with equal cross-section (2) can be adjusted to the target position by replacing the hydraulic cylinder simulation support (3). The counterweight (4) is installed on both sides of the main frame (1) and at the end of the beam with equal cross-section (2). The dynamic vibration absorber includes a mass block (5), a magnetorheological damper (6), an elastic element (7), and a mounting assembly. By adjusting the mass of the mass block (5) and the stiffness of the elastic element, the natural frequency of the dynamic vibration absorber is adjusted to be close to the desired control mode frequency. The magnetorheological damper (6) is used to perform semi-active control on the equal cross-section beam (2). The dynamic vibration absorber can be set at a preset experimental position on the upper end of the equal cross-section beam (2) through the mounting assembly. The excitation point of the exciter (12) can be connected to a beam (2) with a uniform cross section or a dynamic vibration absorber to realize modal analysis experiments and semi-active vibration control experiments; the sensors of the sensor measurement module (13) are set at the corresponding test nodes, and the dynamic signal acquisition module (10) is used to receive the excitation signal sent by the terminal and the measurement data returned by the sensor measurement module (13), and can transmit the excitation signal and measurement data to the power amplifier (11) and the terminal (14) respectively; the power amplifier (11) is used to drive the exciter (12) to excite the cantilever beam vibration test platform; the PLC control module (15) is used to send electrical signals to the dynamic vibration absorber based on the measurement data returned by the sensor measurement module (13) to realize semi-active control.

2. The semi-active control experimental system for vibration of a cantilever beam with concentrated end mass according to claim 1, characterized in that: The main frame (1) is an H-shaped structure. The equal cross-section beam (2) is hinged to the middle frame of the main frame (1). The counterweight (4) is installed by bolts at the reserved holes on the main frame (1) and the equal cross-section beam (2) and the number can be adjusted. The counterweight (4) is used to simulate the concentrated mass represented by the tunneling equipment drum and increase the mass of the main frame (1) to reduce the vibration of the main frame when the equal cross-section beam (2) is excited.

3. The semi-active control experimental system for vibration of a cantilever beam with concentrated end mass according to claim 1, characterized in that: The mounting components of the dynamic vibration absorber include a vibration absorber base (8) and a stud (9). The vibration absorber base (8) is set at the beam (2) with equal cross section through the stud (9). The elastic element (7) includes a guide rail and a compression spring that is movably sleeved outside the guide rail. The guide rail is fixedly inserted into the hole at the upper end of the stud (9). The mass block (5) is slidably connected to the guide rail and located at the upper end of the compression spring. A linear bearing is installed in the hole corresponding to the guide rail at the mass block (5). The mass block (5) and the vibration absorber base (8) are connected through a magnetorheological rheostat (6). The damping force of the magnetorheological rheostat (6) is changed based on the PLC control module (15) to change the position of the mass block (5).

4. The semi-active control experimental system for vibration of a cantilever beam with concentrated end mass according to claim 3, characterized in that: The stud (9) is an irregular stud, and the stud head has two concentric holes from the top down. The two concentric holes are used to install the guide rail and the compression spring, respectively. The side wall of the stud head has a threaded hole on the inside. The guide rail is locked onto the stud (9) by a screw inserted into the threaded hole.

5. The semi-active control experimental system for vibration of a cantilever beam with concentrated end mass according to claim 1, characterized in that: The sensor measurement module (13) includes an accelerometer, a force sensor, a miniature tension sensor and a laser displacement sensor, used to measure acceleration, force conditions and displacement of target nodes during the experiment; Accelerometers are installed at equal intervals on the surface of the beam (2) or on the mass block (5), force sensors are installed at the connection between the exciter (12) and the beam (2) or the connection between the exciter (12) and the shock absorber base (8), miniature tension sensors are installed at the connection between the mass block (5) and the magnetorheological damper (6), and laser displacement sensors are installed at the end of the beam (2).

6. The semi-active control experimental system for vibration of a cantilever beam with concentrated end mass according to claim 1, characterized in that: The dynamic signal acquisition module (10) includes a dynamic signal acquisition card, a signal source card, and a speed / counter measurement card. The dynamic signal acquisition card is used to acquire sensor signals, the signal source card sends excitation signals to the power amplifier, and the speed / counter measurement card is used for speed or frequency counting. The terminal (14) is used to calculate the modes of the test object and their frequency response curves. The power amplifier (11) is used to adjust the amplitude of the output signal to meet the excitation force required for the experiment.

7. A semi-active control experimental method for the vibration of a cantilever beam with concentrated end mass, based on the semi-active control experimental system for the vibration of a cantilever beam with concentrated end mass as described in any one of claims 1 to 6, characterized in that, Includes the following steps: S1: Assemble the cantilever beam vibration test bench, select the hydraulic cylinder to simulate the support (3) so that the position of the equal cross section beam (2) is the target position, select the counterweight block (4) with preset weight to simulate the concentrated mass represented by the tunneling equipment drum and increase the mass of the main frame (1); connect the excitation point of the vibrator (12) to the end of the equal cross section beam (2); S2: The acceleration sensors are set at equal intervals on the surface of the beam (2) with equal cross-section, and the force sensor is installed at the connection between the exciter (12) and the beam (2) with equal cross-section; S3: Connect the exciter (12), sensor measurement module (13), dynamic signal acquisition module (10), power amplifier (11), and terminal (14); S4: Start the vibrator (12) to vibrate the end of the beam (2) with uniform cross section; S5: The terminal (14) determines the amplitude and shape of the output signal and adjusts it through the power amplifier (11); S6: Calculate and plot the frequency characteristics of the entire end-concentrated mass cantilever beam vibration test bench, identify the natural frequencies and mode shapes of each mode, and denote the experimentally obtained natural frequencies as follows: The frequencies obtained from ANSYS calculations are as follows: ,like Then check and modify the simulation model and experimental model, and repeatedly record the natural frequencies obtained from the experiment and the frequencies calculated by ANSYS, while calculating... ,until ; S7: Separate the vibrator (12) from the beam (2) with equal cross section, connect the vibration absorber base (8) to the vibrator (12), install an acceleration sensor on the mass block (5), and install a force sensor at the connection between the vibration absorber base (8) and the vibrator (12); S8: Excite the dynamic vibration absorber using the exciter (12) and calculate the natural frequency of the dynamic vibration absorber. ,like , To determine the modal order for which vibration reduction is to be performed, repeat step S8 until... ; S9: Separate the vibration absorber base (8) from the exciter (12), connect the excitation point of the exciter (12) to the end of the equal cross-section beam (2), install the dynamic vibration absorber at the preset position of the equal cross-section beam (2), install an acceleration sensor on the mass block (5), install a force sensor at the connection between the exciter (12) and the equal cross-section beam (2), install a miniature tensile and compressive sensor at the connection between the magnetorheological damper (6) and the vibration absorber base (8), distribute acceleration sensors evenly on the equal cross-section beam (2), and install a laser displacement sensor at the end; S10: Excite the end of the beam (2) with equal cross section, and control the damping force of the magnetorheological damper (6) by the PLC control module (15) to complete the semi-active vibration control. S11: Recalculate and plot the frequency characteristics of the system, determine the natural frequencies and mode shapes of each mode, and compare them with the frequency characteristic curves before the addition of the dynamic vibration absorber to verify the control effect of the algorithm.

8. The experimental method for semi-active control of vibration of a cantilever beam with concentrated end mass according to claim 7, characterized in that: The vibration direction of the exciter (12) is perpendicular to the upper surface of the beam (2) with uniform cross section.

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