A method and system for suppressing low-frequency resonance of a press

Abstract

The present invention provides a method and system for suppressing low-frequency resonance of a press, comprising the following steps: obtaining multiple modal vibration modes and corresponding vibration frequencies of the press through finite element analysis and vibration testing; determining the vibration frequency ranges at different component locations of the press body; and disposing at least one set of three-axis acceleration sensors and a resonance suppression unit at the peak location of the comprehensive vibration frequency within the press body. The resonance suppression unit includes nonlinear dynamic vibration absorbers distributed along the x-axis, y-axis, and z-axis, respectively. The three-axis acceleration sensors periodically collect vibration signals from the press, calculate and obtain the resonance frequencies of the press in the three axes, and adjust the vibration control efficiency of the nonlinear dynamic vibration absorbers distributed along the x-axis, y-axis, and z-axis accordingly, thereby suppressing the low-frequency resonance frequencies of the press in the vertical and horizontal directions to within a preset range. The present invention can achieve dynamic resonance suppression of the press in the vertical and horizontal directions.

Description

Technical Field

[0001] The present invention belongs to the technical field of presses, and in particular relates to a method and system for suppressing low-frequency resonance of a press. Background Art

[0002] A press is a type of mechanical equipment widely used in industrial manufacturing. It is mainly used in processes such as metal forming, stamping, and die forging. It can produce the required parts or products with special shapes by applying high pressure to cause the material to undergo plastic deformation.

[0003] Any press has a resonant frequency, which is determined by the physical properties of the press components, such as mass and stiffness. When the frequency of the periodic force generated by the press during stamping is close to or equal to the resonant frequency of the press, the press will resonate. The resonance phenomenon can easily lead to structural fatigue and loose connections of the press components, affecting the processing accuracy and operational safety of the press.

[0004] In the existing technology, the vibration isolation method for presses generally includes setting a vertically arranged vibration isolator at the bottom of the press to isolate the broadband vibration caused by impact. However, the traditional vibration isolator composed of springs and viscous dampers generally has a frequency greater than the resonant frequency of the press. The vibration isolation effect begins to occur in the frequency region of times, so it is only effective for isolating high-frequency vibration components, and cannot effectively isolate low-frequency vibrations and resonances induced by impact, nor can it effectively suppress the vibrations generated by the press in the horizontal direction. In addition, the vibration isolation method for the press also includes setting a tuned mass damper on the press body, but the conventional method of using a tuned mass damper is generally to set the vibration control efficiency of the tuned mass damper to a fixed parameter, that is, it is impossible to flexibly and accurately adjust the vibration control efficiency according to the actual vibration conditions of the press, resulting in poor resonance suppression effect of the press. For example, when the vibration control efficiency of the tuned mass damper is set too weak, the resonance of the press cannot be fully suppressed. When the vibration control efficiency of the tuned mass damper is set too strong, it will affect the normal stamping force release of the press. Summary of the Invention

[0005] The present invention provides a method and system for suppressing low-frequency resonance of a press, so as to solve the technical problem in the prior art that conventional presses cannot realize multi-directional resonance frequency detection and resonance frequency suppression functions during stamping operations.

[0006] To solve the above problems, the technical solution of the present invention is: a method for suppressing low-frequency resonance of a press, comprising the following steps:

[0007] S1: Through finite element analysis and vibration testing, obtain the multi-order modal vibration shapes and corresponding vibration frequencies of the press under theoretical conditions;

[0008] S2: Based on the multi-order modal vibration shapes and corresponding vibration frequency data of the press, determine the vibration frequency range of different components of the press body, and configure at least one set of three-axis acceleration sensors and resonance suppression units at the peak position of the comprehensive vibration frequency in the press body, wherein the resonance suppression unit includes nonlinear dynamic vibration absorbers distributed along the x-axis, y-axis, and z-axis respectively;

[0009] S3: The three-axis acceleration sensor periodically collects the vibration signal of the press, calculates and obtains the resonance frequency of the press in the three-axis direction, and the nonlinear dynamic vibration absorber distributed along the x-axis, y-axis and z-axis adjusts its vibration control efficiency accordingly based on the real-time resonance frequency of the press in the three-axis direction, thereby suppressing the low-frequency resonance frequency of the press in the vertical and horizontal directions to be within a preset range.

[0010] Preferably, in S1, finite element analysis and vibration simulation testing are used to obtain multi-order modal vibration shapes and corresponding vibration frequencies of pressure, which specifically includes the following steps:

[0011] S11: establishing a three-dimensional model of the press in the simulation software, simplifying the main structure of the three-dimensional model of the press, and eliminating unnecessary structural features in the three-dimensional model of the press;

[0012] S12: dividing the three-dimensional model of the press into a plurality of tetrahedral mesh units with a preset accuracy;

[0013] S13: defining material properties of different components of the press three-dimensional model in the simulation software, setting boundary conditions of the press three-dimensional model, and inputting simulated load conditions applied to the press three-dimensional model;

[0014] S14: Simulate and calculate the multi-order modal vibration shapes and corresponding vibration frequency data of the three-dimensional model of the press under different vibration simulation test conditions.

[0015] Preferably, in S3, the three-axis acceleration sensor collects the vibration signal of the press, and calculates and obtains the resonance frequency of the press in the three-axis directions, which specifically includes the following steps:

[0016] S31: The main controller obtains the production rhythm parameters of the press and evenly divides the single stamping action time of the press into several minimum resonance suppression cycles;

[0017] S32: The triaxial acceleration sensor uses the minimum resonance suppression period as a sampling period to collect the vibration signal of the press and transmits it to the main controller. The main controller uses the minimum resonance suppression period as a processing window to sequentially perform fast Fourier transform processing on the vibration signal of the press to obtain resonance spectrum diagrams of the press within several minimum resonance suppression periods.

[0018] S33: The main controller calculates the frequency component amplitude of each resonance spectrum graph respectively, and traverses all amplitude values ​​in the resonance spectrum graph, and sets the maximum amplitude value in each resonance spectrum graph as the resonance frequency of the current resonance suppression minimum period.

[0019] Preferably, the step of collecting the vibration signal of the press by the three-axis acceleration sensor in S32 further includes the following steps:

[0020] S321: The three-axis acceleration sensor collects the acceleration data of the press in the x-axis, y-axis and z-axis directions to form an acceleration sample set and transmits it to the main controller. The main controller filters the vibration signal of the press through a low-pass filter, a high-pass filter, a band-pass filter or a band-stop filter, and performs noise suppression on the vibration signal of the press through adaptive filtering, wavelet transform or spectral subtraction to obtain the pre-processed press vibration signal.

[0021] Preferably, the nonlinear dynamic vibration absorber adopts a disc spring to provide nonlinear stiffness characteristics, and the nonlinear dynamic vibration absorber is provided with a mass block for absorbing resonance energy;

[0022] In S3, the nonlinear dynamic vibration absorbers distributed along the x-axis, y-axis, and z-axis adjust their vibration control performance accordingly based on the real-time resonance frequency of the press in the three-axis directions, specifically including the following steps:

[0023] S34: Within any minimum resonance suppression period, based on the resonance frequencies of the press in the three axes, calculate the required suppression stiffness of the press in the three axes that matches the corresponding resonance frequencies. The calculation method of the required suppression stiffness is:

[0024]

[0025] Among them, k req To suppress the required stiffness, m is the mass of the mass block of the nonlinear dynamic vibration absorber, f dom is the resonant frequency of the press in the uniaxial direction;

[0026] S35: The calculation method of the disc spring stiffness of the nonlinear dynamic vibration absorber is:

[0027]

[0028] Among them, k z is the disk spring stiffness of the nonlinear dynamic vibration absorber, E is the elastic modulus of the disk spring of the nonlinear dynamic vibration absorber, t is the thickness of the disk spring of the nonlinear dynamic vibration absorber, K1 is the geometric coefficient of the disk spring of the nonlinear dynamic vibration absorber, and D is the coil diameter of the disk spring of the nonlinear dynamic vibration absorber;

[0029] S36: Establishing a pre-compression-stiffness relationship model of the disc spring of the nonlinear dynamic vibration absorber. The pre-compression-stiffness relationship model is expressed as:

[0030]

[0031] Among them, k base is the rigid reference parameter, β is the calibration coefficient, is the compression displacement of the disc spring of the nonlinear dynamic vibration absorber;

[0032] By adjusting the pre-compression amount of the disc spring of the nonlinear dynamic vibration absorber, the disc spring stiffness of the nonlinear dynamic vibration absorber is made close to the required stiffness of the press. Therefore, the main controller controls the disc spring compression displacement adjustment instruction of the nonlinear dynamic vibration absorber as follows:

[0033] .

[0034] Preferably, during a single stamping action of the press, the main controller adjusts the vibration control efficiency of the nonlinear dynamic vibration absorber in several resonance suppression minimum cycles through a PID closed-loop feedback control method, specifically: the low-frequency resonance frequency of the press is defined as the set value of the PID control within a preset range, the low-frequency resonance frequency of the press after adjustment in each resonance suppression minimum cycle is the process variable of the PID control, and the difference between the set value and the process variable of the press after adjustment in each resonance suppression minimum cycle is the error of the PID control.

[0035] Preferably, a method for suppressing low-frequency resonance of a press further includes the following steps:

[0036] S4: A resonance frequency alarm limit is set. When the three-axis acceleration sensor collects the vibration signal of the press and calculates that the resonance frequency of the press in the three-axis direction exceeds the resonance frequency alarm limit, the press stops the stamping operation and outputs an alarm signal.

[0037] Based on the same concept, the present invention further provides a press low-frequency resonance suppression system, which is used to perform any of the press low-frequency resonance suppression methods described above, comprising:

[0038] A press, comprising a body, a stamping slide assembly and a stamping platform;

[0039] A three-axis acceleration sensor is used to measure the vibration signals of the press in the x-axis, y-axis and z-axis directions;

[0040] A resonance suppression unit, the resonance suppression unit comprising nonlinear dynamic vibration absorbers distributed along the x-axis, y-axis, and z-axis, respectively, the resonance suppression unit being used to suppress low-frequency resonance of the press in the x-axis, y-axis, and z-axis directions;

[0041] The three-axis acceleration sensor and the resonance suppression unit are each provided with four groups, which are respectively arranged at the four corners of the top of the crossbeam of the fuselage.

[0042] Preferably, the nonlinear dynamic vibration absorber includes a mass block, a slide rail, a nonlinear disc spring and a ball screw servo motor;

[0043] The slide rail is extended along the height direction of the nonlinear dynamic vibration absorber, the mass block is slidably connected to the slide rail, the bottom of the mass block is provided with the nonlinear disc spring extended along the height direction of the nonlinear dynamic vibration absorber, the first end of the nonlinear disc spring abuts against the mass block, the ball screw servo motor is configured to drive the mass block to move, the mass block compresses the nonlinear disc spring, causing the nonlinear disc spring to produce a compressed displacement.

[0044] Preferably, four groups of vertically arranged vibration isolators are respectively provided at the four corners of the bottom of the fuselage, and the vibration isolators are used to isolate the high-frequency vibration generated by the press during the stamping operation;

[0045] The nonlinear dynamic vibration absorber also includes a damper, in which a silicon-based damping fluid is provided. The second end of the nonlinear disc spring abuts against the movable end surface of the damper. The damper is configured such that the ball screw servo motor drives the mass block to move, and the mass block compresses the nonlinear disc spring, causing the nonlinear disc spring to compress the silicon-based damping fluid inside the damper, thereby adjusting the vibration control performance of the nonlinear dynamic vibration absorber.

[0046] Due to the adoption of the above technical solution, the present invention has the following advantages and positive effects compared with the prior art:

[0047] The present invention provides a method and system for suppressing low-frequency resonance of a press. Finite element analysis and vibration simulation tests determine that the top crossbeam of the press body is the peak position of the comprehensive vibration frequency. Therefore, three-axis acceleration sensors and resonance suppression units are respectively arranged at the four corners of the top of the crossbeam of the press. The resonance suppression unit includes nonlinear dynamic vibration absorbers distributed along the x-axis, y-axis and z-axis respectively. During the stamping operation of the press, the three-axis acceleration sensor collects the vibration signal of the press, and the main controller calculates and obtains the resonance frequency of the press in the three-axis direction. The nonlinear dynamic vibration absorbers distributed along the x-axis, y-axis and z-axis adjust their vibration control efficiency accordingly based on the real-time resonance frequency of the press in the three-axis direction, thereby suppressing the low-frequency resonance frequency of the press in the vertical and horizontal directions within a preset range, fully improving the stamping accuracy, stability and production efficiency of the press, and avoiding unnecessary energy consumption. The method has important theoretical and practical application value for promoting the research and manufacture of high-precision, low-vibration and noise, and environmentally friendly large-scale stamping equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 A flow chart of a method for suppressing low-frequency resonance of a press provided by the present invention;

[0049] Figure 2 A schematic structural diagram of a press provided by the present invention;

[0050] Figure 3 A schematic structural diagram of the nonlinear dynamic vibration absorber provided by the present invention;

[0051] Figure 4 Comparison diagram of the resonance frequency of the press provided by the present invention near the 2 Hz frequency band in one direction;

[0052] Figure 5 A comparison diagram of the resonance frequencies of the press provided by the present invention near the 6 Hz frequency band in one direction.

[0053] Explanation of the reference numerals: 1: press; 11: crossbeam; 12: stamping slide; 13: column; 14: stamping platform; 15: base; 16: vibration isolator; 2: nonlinear dynamic vibration absorber; 21: mass block; 22: ball screw servo motor; 23: disc spring; 24: slide rail; 25: damper. DETAILED DESCRIPTION

[0054] The advantages and features of the present invention will become more apparent from the following description and claims.

[0055] First embodiment

[0056] See Figure 1-Figure 3This embodiment provides a method for suppressing low-frequency resonance of a press, which is used to achieve dynamic suppression of resonance of a press 1 in the vertical and horizontal directions, and includes the following steps:

[0057] S1: Through finite element analysis and vibration simulation testing, obtain the multi-order modal vibration shapes and corresponding vibration frequencies of the press 1 under theoretical conditions.

[0058] S2: Based on the multi-order modal vibration modes and corresponding vibration frequency data of the press 1, the vibration frequency range at different component positions of the press 1 entity is determined, the comprehensive vibration frequency peak position in the press 1 entity is selected, and at least one set of three-axis acceleration sensors and one set of resonance suppression units are configured at the comprehensive vibration frequency peak position in the press 1 entity. The resonance suppression unit includes nonlinear dynamic vibration absorbers 2 distributed along the x-axis, y-axis and z-axis respectively.

[0059] In this embodiment, simulation results indicate that the top of press 1 (crossbeam 11) is the peak location of the integrated vibration frequency. Triaxial acceleration sensors and nonlinear dynamic vibration absorbers 2 distributed along the x-, y-, and z-axes are installed at the four corners of press beam 11. For press 1 facing the observer, the x-axis represents the horizontal direction of press 1, the y-axis represents the horizontal direction of press 1, and the z-axis represents the vertical direction.

[0060] Among them, the nonlinear dynamic vibration absorber 2, also known as a nonlinear energy well, is composed of a nonlinear equivalent spring-mass system installed on a vibrating machine. Its core mechanism does not rely on matching a fixed resonant frequency, but rather on capturing transient resonance and absorbing energy, that is, utilizing nonlinear target energy transfer and adaptive frequency response to achieve broadband vibration absorption. Therefore, it has excellent robustness in adapting to changes in the resonant frequency of the press 1, and has broadband energy dissipation capabilities.

[0061] S3: The three-axis acceleration sensor periodically collects the vibration signal of the press 1, calculates and obtains the resonance frequency of the press 1 in the three-axis direction, and the nonlinear dynamic vibration absorber 2 distributed along the x-axis, y-axis and z-axis adjusts its vibration control efficiency accordingly based on the real-time resonance frequency of the press 1 in the three-axis direction, thereby suppressing the low-frequency resonance frequency of the press 1 in the vertical and horizontal directions to be within a preset range.

[0062] In summary, this embodiment provides a method for suppressing low-frequency resonance of a press. At the peak position of the comprehensive vibration frequency of the press 1, the vibration frequency of the press 1 in the three-axis direction is detected by a three-axis acceleration sensor. When the vibration frequency exceeds a preset threshold, the nonlinear dynamic vibration absorber 2 in the corresponding direction dynamically adjusts its vibration control efficiency to suppress the resonance frequency of the press 1 in this direction within a preset range. By cooperating with four groups of three-axis acceleration sensors and the resonance suppression unit, it is ensured that the vertical and horizontal low-frequency resonances of the press 1 caused by the stamping work excitation are effectively suppressed, thereby improving the processing accuracy and equipment stability of the press 1 during the stamping operation.

[0063] The specific implementation steps and functions of the method for suppressing low-frequency resonance of a press provided by this embodiment will be further described in detail below:

[0064] Preferably, in one embodiment, the method of obtaining the multi-order modal shapes and corresponding vibration frequencies of the pressure by using finite element analysis and vibration simulation testing in S1 specifically includes the following steps:

[0065] S11: Create a three-dimensional model of press 1 in simulation software (such as ANSYS, ABAQUS, NASTRAN, etc.), simplify the main structure of the three-dimensional model of press 1, eliminate unnecessary structural features in the three-dimensional model of press 1, such as deleting the process fillets and chamfers of all parts, and properly repair the three-dimensional model by filling, merging faces, etc., thereby improving the subsequent simulation calculation efficiency and analyticity of the three-dimensional model of press 1.

[0066] S12: The three-dimensional model of the press 1 is segmented into a plurality of tetrahedral mesh cells with a predetermined accuracy. Each tetrahedral mesh cell has nodes, and adjacent tetrahedral mesh cells are connected by nodes. In this embodiment, the tetrahedral mesh cell size is controlled to 30 mm * 30 mm * 30 mm. The refined tetrahedral mesh cells are used to ensure the accuracy and convergence of the calculation results.

[0067] S13: Define the material properties of different components of the three-dimensional model of Press 1 in the simulation software, such as elastic modulus, Poisson's ratio, density, etc., to ensure that different components in the three-dimensional model of Press 1 can accurately and truly reflect the physical properties of the actual materials.

[0068] Set the boundary conditions of the 3D model of Press 1, such as the fixed point and symmetry plane of Press 1.

[0069] And according to the actual working condition of the press 1, the simulated load conditions applied to the three-dimensional model of the press 1 are input into the simulation software, such as the external loads such as applied force, pressure, temperature, etc. that each component in the three-dimensional model of the press 1 bears during the stamping process of the stamping machine.

[0070] S14: Simulate and calculate the multi-order modal vibration shapes and corresponding vibration frequency data of the three-dimensional model of the press 1 under different vibration simulation test conditions.

[0071] By analyzing the multi-order modal vibration modes and corresponding vibration frequency data of the press 1, the vibration frequency ranges at different parts of the press 1 entity can be obtained. In this embodiment, the peak value of the three-axis comprehensive vibration frequency measured at the position of the crossbeam 11 of the press 1 is the highest, so the crossbeam 11 of the press 1 is selected as the layout position of the three-axis acceleration sensor and the resonance suppression unit. When the resonance suppression at the position of the crossbeam 11 of the press 1 is within the preset range, it means that the overall resonance suppression of the press 1 is within the preset range.

[0072] Preferably, in one embodiment, in S3, a three-axis acceleration sensor collects vibration signals of the press 1, and calculates and obtains the resonance frequencies of the press 1 in the three-axis directions, which specifically includes the following steps:

[0073] S31: The main controller obtains the production rhythm parameters of the press 1, such as the number of punching times per minute, and further evenly divides the single punching action time of the press 1 into several resonance suppression minimum cycles.

[0074] S32: The triaxial acceleration sensor uses the minimum resonance suppression period as its sampling period to collect vibration signals from press 1 and transmit them to the main controller. In this embodiment, the main controller is responsible for digitally processing the vibration signals and controlling the operating parameters of press 1 and the vibration control performance of nonlinear dynamic vibration absorber 2. Using the minimum resonance suppression period as its processing window, the main controller sequentially performs fast Fourier transform (FFT) processing on the vibration signals of press 1, converting the acceleration signals in the time domain into frequency domain representations. The main controller then obtains resonance spectra of press 1 within several minimum resonance suppression periods. The resonance spectra reflect the changes in the resonance frequency of press 1 within a single minimum resonance suppression period.

[0075] S33: The main controller calculates the amplitude of the frequency component of each resonance spectrum diagram respectively, and traverses all the amplitude values ​​in the resonance spectrum diagram, and sets the maximum amplitude value in each resonance spectrum diagram as the resonance frequency of the current minimum resonance suppression period. Within the current minimum resonance suppression period, the nonlinear dynamic vibration absorber 2 adjusts its vibration control efficiency based on the resonance frequency.

[0076] It is worth noting that, in this embodiment, any set of triaxial acceleration sensors and nonlinear dynamic vibration absorbers 2 operates independently. For example, if the triaxial acceleration sensor at the first position of the crossbeam 11 of the press 1 detects resonance in the x-axis direction at the first position of the press 1, but no resonance is detected in the y-axis and z-axis directions, then the nonlinear dynamic vibration absorber 2 located at the first position of the crossbeam 11 of the press 1 and arranged along the x-axis adjusts its vibration control efficiency, while the nonlinear dynamic vibration absorbers 2 arranged along the y-axis and z-axis do not participate in the vibration control efficiency adjustment.

[0077] In other embodiments, the number of three-axis acceleration sensors and resonance suppression units is not limited to four groups. Several groups of three-axis acceleration sensors and resonance suppression units are arranged at different positions of the press 1, which can independently detect the vibration frequency of the press 1 at different positions, thereby improving the detection accuracy of abnormal vibration when a single component of the press 1 is separated from the press 1 due to vibration. The arrangement of four groups of three-axis acceleration sensors and resonance suppression units is for the purpose of achieving the optimal balance between cost and resonance suppression effect.

[0078] Preferably, in one embodiment, in S32, the three-axis acceleration sensor collects the vibration signal of the press 1, and further comprises the following steps:

[0079] S321: The three-axis acceleration sensor collects the acceleration data of the press 1 in the x-axis, y-axis and z-axis directions to form an acceleration sample set and transmits it to the main controller. The main controller filters the vibration signal of the press 1 through a low-pass filter, a high-pass filter, a band-pass filter or a band-stop filter, and performs noise suppression on the vibration signal of the press 1 through adaptive filtering, wavelet transform or spectral subtraction, so that the vibration signal is free of noise interference, thereby obtaining the preprocessed vibration signal of the press 1.

[0080] Preferably, in one embodiment, the nonlinear dynamic vibration absorber 2 includes a mass block 21, a slide rail 24, a nonlinear disc spring 23, and a ball screw servo motor 22. The slide rail 24 extends along the height direction of the nonlinear dynamic vibration absorber 2 (e.g., if the nonlinear dynamic vibration absorber 2 is arranged along the x-axis, its slide rail 24 is also arranged along the x-axis). The mass block 21 is slidably connected to the slide rail 24. A nonlinear disc spring 23 is provided at the bottom of the mass block 21 and extends along the height direction of the nonlinear dynamic vibration absorber 2. The first end of the nonlinear disc spring 23 abuts the mass block 21. The ball screw servo motor 22 is configured to drive the mass block 21 to move. The mass block 21 compresses the nonlinear disc spring 23, causing the nonlinear disc spring 23 to produce a compressed displacement.

[0081] Among them, the nonlinear dynamic vibration absorber 2 uses a disc spring 23 to provide nonlinear stiffness characteristics, and uses a mass block 21 to absorb resonance energy. That is, when it is detected that the press 1 has enhanced resonance, the ball screw servo motor 22 can adjust the disc spring 23 to stretch, so that the resonance energy absorption performance of the mass block 21 is correspondingly enhanced. Conversely, when it is detected that the press 1 has weakened resonance, the ball screw servo motor 22 can adjust the disc spring 23 to contract, so that the resonance energy absorption performance of the mass block 21 is correspondingly weakened.

[0082] In S3, the nonlinear dynamic vibration absorbers 2 distributed along the x-axis, y-axis, and z-axis adjust their vibration control performance accordingly based on the real-time resonance frequency of the press 1 in the three-axis directions, specifically including the following steps:

[0083] S34: Within any minimum resonance suppression period, based on the resonance frequencies of the press 1 in the three axial directions, the required suppression stiffness of the press 1 in the three axial directions that matches the corresponding resonance frequencies (i.e., the external force stiffness required to suppress the resonance of the press 1 and adjust it to within a preset range) is calculated. The required suppression stiffness is calculated as follows:

[0084]

[0085] Among them, k req To suppress the required stiffness, m is the mass of the mass block 21 of the nonlinear dynamic vibration absorber 2, and f dom is the resonance frequency of the press 1 in a single axis direction.

[0086] S35: For the nonlinear dynamic vibration absorber 2 structure provided in this embodiment, the stiffness of the disc spring 23 of the nonlinear dynamic vibration absorber 2 is calculated as follows:

[0087]

[0088] Among them, k z is the stiffness of the disc spring 23 of the nonlinear dynamic vibration absorber 2, E is the elastic modulus of the disc spring 23 of the nonlinear dynamic vibration absorber 2, t is the thickness of the disc spring 23 of the nonlinear dynamic vibration absorber 2, K1 is the geometric coefficient of the disc spring 23 of the nonlinear dynamic vibration absorber 2 (related to the inner diameter, outer diameter and thickness ratio, determined by empirical formula or experiment), and D is the coil diameter of the disc spring 23 of the nonlinear dynamic vibration absorber 2.

[0089] S36: Establishing a pre-compression amount-stiffness relationship model of the disc spring 23 of the nonlinear dynamic vibration absorber 2. The pre-compression amount-stiffness relationship model is expressed as:

[0090]

[0091] Among them, k baseis the stiffness reference parameter (the initial stiffness of the disc spring 23 without precompression or with a reference precompression amount), β is the calibration coefficient (obtained from the stiffness test curve of the disc spring 23), is the compression displacement of the disc spring 23 of the nonlinear dynamic vibration absorber 2.

[0092] By adjusting the pre-compression amount of the disc spring 23 of the nonlinear dynamic vibration absorber 2, the stiffness of the disc spring 23 of the nonlinear dynamic vibration absorber 2 is made close to the required stiffness of the press 1. That is, the required stiffness is provided by the nonlinear dynamic vibration absorber 2. Therefore, the main controller controls the compression displacement adjustment instruction of the disc spring 23 of the nonlinear dynamic vibration absorber 2 as follows:

[0093]

[0094] In this way, the nonlinear dynamic vibration absorber 2 achieves the dynamic suppression function of the press 1 resonance.

[0095] Preferably, in one embodiment, during a single stamping action of the press 1, the main controller adjusts the vibration control efficiency of the nonlinear dynamic vibration absorber 2 in several resonance suppression minimum cycles through a PID closed-loop feedback control method, specifically: the low-frequency resonance frequency of the press 1 is defined as the set value of the PID control within a preset range, the low-frequency resonance frequency of the press 1 after adjustment in each resonance suppression minimum cycle is the process variable of the PID control, and the difference between the set value and the process variable of the press 1 after adjustment in each resonance suppression minimum cycle is the error of the PID control.

[0096] With the help of PID control, the dynamic response speed and stability of the nonlinear dynamic vibration absorber 2 can be improved, ensuring that the resonance of the press 1 can be effectively suppressed and accurately adjusted.

[0097] Preferably, in one embodiment, the method for suppressing low-frequency resonance of the press 1 further includes the following steps:

[0098] S4: A resonance frequency alarm limit is set. When the three-axis acceleration sensor collects the vibration signal of the press 1 and the calculated resonance frequency of the press 1 in the three-axis direction exceeds the resonance frequency alarm limit, it means that the resonance of the press 1 is too high and has exceeded the safe and controllable range. The press 1 stops the stamping operation and outputs an alarm signal.

[0099] See Figure 4-Figure 5 , is a comparison diagram of the resonance test frequencies near the 2 Hz frequency band and the 6 Hz frequency band in one direction after the press 1 is equipped with a three-axis acceleration sensor and a resonance suppression unit in this embodiment. It can be seen from the figure that the resonance of the press 1 in its resonance zone is significantly suppressed.

[0100] Second embodiment

[0101] Based on the same concept, the present invention also provides a press low-frequency resonance suppression system for executing the press low-frequency resonance suppression method described in the first embodiment, comprising a press 1, a triaxial acceleration sensor and a resonance suppression unit.

[0102] The main structure of the press 1 includes a fuselage, a stamping slide assembly, and a stamping platform 14. The top of the fuselage is a crossbeam 11 component, the side is provided with a column 13 component for support, and the bottom is a base 15. The stamping slide assembly and the stamping platform 14 are arranged in the internal cavity space of the fuselage. The stamping slide assembly is movably arranged in the space above the stamping platform 14. The stamping slide assembly includes a power system and a stamping slide 12. During the stamping operation of the lower press, the stamping slide 12 is pressed vertically from top to bottom onto the stamping platform 14, applying pressure to the workpiece on the stamping platform 14.

[0103] The three-axis acceleration sensor is used to measure acceleration data of the press 1 in the x-axis, y-axis and z-axis directions, which in this embodiment is the vibration signal of the press 1 in the x-axis, y-axis and z-axis directions.

[0104] The resonance suppression unit includes nonlinear dynamic vibration absorbers 2 distributed along the x-axis, y-axis and z-axis respectively. The resonance suppression unit is used to suppress low-frequency resonance of the press 1 in the x-axis, y-axis and z-axis directions.

[0105] In this embodiment, four groups of triaxial acceleration sensors and resonance suppression units are provided, respectively arranged at the four corners of the top of the fuselage cross beam 11. Specifically, with respect to the press machine 1 facing the observer, the first position at a corner of the top of the fuselage cross beam 11 is used for illustration. The x-axis nonlinear dynamic vibration absorber 2 is vertically arranged on the lateral side wall of the first position at the top of the fuselage cross beam 11, the y-axis nonlinear dynamic vibration absorber 2 is vertically arranged on the longitudinal side wall of the first position at the top of the fuselage cross beam 11, and the z-axis nonlinear dynamic vibration absorber 2 is vertically arranged on the vertical top surface of the first position at the top of the fuselage cross beam 11.

[0106] It is also worth noting that, in this embodiment, the three-axis acceleration sensor at each corner position on the top of the fuselage cross beam 11 and the resonance suppression unit are an integral structure, that is, the resonance suppression unit only adjusts the vibration control performance accordingly based on the vibration signal measured by the corresponding three-axis acceleration sensor.

[0107] Preferably, in one embodiment, the nonlinear dynamic vibration absorber 2 includes a mass block 21 , a slide rail 24 , a nonlinear disc spring 23 and a ball screw servo motor 22 .

[0108] The slide rail 24 extends along the height of the nonlinear dynamic vibration absorber 2. The mass 21 is slidably connected to the slide rail 24 and can slide along the extension direction of the slide rail 24. This allows the mass 21 to vary its height within the nonlinear dynamic vibration absorber 2. Nonlinear disc springs 23 are installed at the bottom of the mass 21, extending along the height of the nonlinear dynamic vibration absorber 2. Two sets of nonlinear disc springs 23 are symmetrically located on either side of the bottom of the mass 21. The first ends (top ends) of the nonlinear disc springs 23 abut the bottom surface of the mass 21. The ball screw servo motor 22 is configured to drive the mass 21 toward or away from the nonlinear disc spring 23. The mass 21 compresses the nonlinear disc spring 23, causing the nonlinear disc spring 23 to produce a compressive displacement (including expansion of the nonlinear disc spring 23 when the mass 21 moves upward and contraction of the nonlinear disc spring 23 when the mass 21 moves downward). In the nonlinear dynamic vibration absorber 2, when the ball screw servo motor 22 adjusts the expansion of the disc spring 23, the resonant energy absorption performance of the mass 21 is enhanced. Conversely, when the ball screw servo motor 22 adjusts the contraction of the disc spring 23, the resonant energy absorption performance of the mass 21 is weakened. In this embodiment, by controlling the compressive displacement of the mass 21 and the nonlinear disc spring 23, the vibration control performance of the nonlinear dynamic vibration absorber 2 can be dynamically adjusted, fully adapting to the resonance suppression requirements of the press 1 at different times. The nonlinear stiffness and damping of the vibration absorber are adjusted according to the vibration characteristics of the press 1 to match the vibration absorption frequency range.

[0109] Preferably, in one embodiment, the press machine 1 body is provided with four groups of vertically arranged vibration isolators 16 at the four corners of the bottom of its base 15. The vibration isolators 16 are used to isolate the high-frequency vibrations generated by the press machine 1 during the stamping operation. By isolating and eliminating the high-frequency vibrations generated by the press machine 1 during the stamping operation, the detection accuracy of the three-axis acceleration sensor only for low-frequency resonance is improved.

[0110] Furthermore, the nonlinear dynamic vibration absorber 2 also includes a damper 25, the interior of the damper 25 is filled with a silicon-based damping fluid, and the second end (bottom end) of the nonlinear disc spring 23 abuts against the movable end surface of the damper 25. Applying pressure to the movable end surface of the damper 25 can change the viscosity of the silicon-based damping fluid inside the damper 25, that is, when the silicon-based damping fluid is compressed, its viscosity increases, and conversely, when the silicon-based damping fluid expands, its viscosity decreases.

[0111] In this embodiment, the damper 25 is configured such that, when the ball screw servo motor 22 drives the mass 21 to move, the mass 21 compresses the nonlinear disc spring 23, causing the nonlinear disc spring 23 to further compress the silicon-based damping fluid within the damper 25, thereby adjusting the vibration control performance of the nonlinear dynamic vibration absorber 2. Specifically, when the ball screw servo motor 22 adjusts the disc spring 23 to expand, the pressure on the silicon-based damping fluid within the damper 25 decreases, the viscosity of the silicon-based damping fluid decreases, and the vibration absorption effect of the damper 25 is enhanced. In combination with the nonlinear disc spring 23 and the mass 21, the resonance energy absorption performance of the mass 21 is improved. Conversely, when the ball screw servo motor 22 adjusts the disc spring 23 to contract, the pressure on the silicon-based damping fluid within the damper 25 increases, the viscosity of the silicon-based damping fluid increases, and the vibration absorption performance of the damper 25 is weakened. In combination with the nonlinear disc spring 23 and the mass 21, the resonance energy absorption performance of the mass 21 is reduced. The cooperation between the nonlinear disc spring 23 and the damper 25 can improve the vibration control performance release efficiency of the nonlinear dynamic vibration absorber 2 .

[0112] In summary, the present invention provides a method and system for suppressing low-frequency resonance of a press. Finite element analysis and vibration simulation tests determine that the top crossbeam 11 of the press 1 is the peak location of the comprehensive vibration frequency. Therefore, three-axis acceleration sensors and resonance suppression units are respectively arranged at the four corners of the top crossbeam 11 of the press 1. The resonance suppression unit includes nonlinear dynamic vibration absorbers 2 distributed along the x-axis, y-axis, and z-axis, respectively. During the stamping operation of the press 1, the three-axis acceleration sensors collect vibration signals of the press 1 in the three-axis directions. The main controller calculates and obtains the resonance frequencies of the press 1 in the three-axis directions. The nonlinear dynamic vibration absorbers 2 distributed along the x-axis, y-axis, and z-axis adjust their vibration control efficiency accordingly based on the real-time resonance frequencies of the press 1 in the three-axis directions, thereby suppressing the low-frequency resonance frequencies of the press 1 in the vertical and horizontal directions to within a preset range, fully improving the stamping accuracy, stability, and production efficiency of the press 1, and avoiding unnecessary energy consumption. This method has important theoretical and practical application value for promoting the research and manufacture of high-precision, low-vibration and noise, and environmentally friendly large-scale stamping equipment.

[0113] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they still fall within the scope of protection of the present invention.

Claims

1. A method for suppressing low-frequency resonance of a press, characterized in that: The steps include: S1: Through finite element analysis and vibration testing, obtain the multi-order modal vibration shapes and corresponding vibration frequencies of the press under theoretical conditions; S2: Based on the multi-order modal vibration shapes and corresponding vibration frequency data of the press, determine the vibration frequency range of different components of the press body, and configure at least one set of three-axis acceleration sensors and resonance suppression units at the peak position of the comprehensive vibration frequency in the press body, wherein the resonance suppression unit includes nonlinear dynamic vibration absorbers distributed along the x-axis, y-axis, and z-axis respectively; S3: The three-axis acceleration sensor periodically collects the vibration signal of the press, calculates and obtains the resonance frequency of the press in the three-axis direction, and the nonlinear dynamic vibration absorber distributed along the x-axis, y-axis and z-axis adjusts its vibration control efficiency accordingly based on the real-time resonance frequency of the press in the three-axis direction, thereby suppressing the low-frequency resonance frequency of the press in the vertical and horizontal directions to be within a preset range.

2. The method for suppressing low-frequency resonance of a press machine according to claim 1, wherein: Finite element analysis and vibration simulation testing are used in S1 to obtain the multi-order modal vibration shapes and corresponding vibration frequencies of the pressure, which specifically includes the following steps: S11: establishing a three-dimensional model of the press in the simulation software, simplifying the main structure of the three-dimensional model of the press, deleting the process fillets and chamfers of all components in the three-dimensional model of the press, and repairing the three-dimensional model of the press by filling and merging surfaces; S12: dividing the three-dimensional model of the press into a plurality of tetrahedral mesh units with a preset accuracy; S13: defining material properties of different components of the press three-dimensional model in the simulation software, setting boundary conditions of the press three-dimensional model, and inputting simulated load conditions applied to the press three-dimensional model; S14: Simulate and calculate the multi-order modal vibration shapes and corresponding vibration frequency data of the three-dimensional model of the press under different vibration simulation test conditions.

3. The method for suppressing low-frequency resonance of a press machine according to claim 1, wherein: In S3, the three-axis acceleration sensor collects the vibration signal of the press and calculates and obtains the resonance frequency of the press in the three-axis directions, which specifically includes the following steps: S31: The main controller obtains the production rhythm parameters of the press and evenly divides the single stamping action time of the press into several minimum resonance suppression cycles; S32: The triaxial acceleration sensor uses the minimum resonance suppression period as a sampling period to collect the vibration signal of the press and transmits it to the main controller. The main controller uses the minimum resonance suppression period as a processing window to sequentially perform fast Fourier transform processing on the vibration signal of the press to obtain resonance spectrum diagrams of the press within several minimum resonance suppression periods. S33: The main controller calculates the frequency component amplitude of each resonance spectrum graph respectively, and traverses all amplitude values ​​in the resonance spectrum graph, and sets the maximum amplitude value in each resonance spectrum graph as the resonance frequency of the current resonance suppression minimum period.

4. The method for suppressing low-frequency resonance of a press machine according to claim 3, wherein: In S32, the three-axis acceleration sensor collects the vibration signal of the press, and further includes the following steps: S321: The three-axis acceleration sensor collects the acceleration data of the press in the x-axis, y-axis and z-axis directions to form an acceleration sample set and transmits it to the main controller. The main controller filters the vibration signal of the press through a low-pass filter, a high-pass filter, a band-pass filter or a band-stop filter, and performs noise suppression on the vibration signal of the press through adaptive filtering, wavelet transform or spectral subtraction to obtain the pre-processed press vibration signal.

5. The method for suppressing low-frequency resonance of a press machine according to claim 3, wherein: The nonlinear dynamic vibration absorber adopts a disc spring to provide nonlinear stiffness characteristics, and the nonlinear dynamic vibration absorber is provided with a mass block for absorbing resonance energy; In S3, the nonlinear dynamic vibration absorbers distributed along the x-axis, y-axis, and z-axis adjust their vibration control performance accordingly based on the real-time resonance frequency of the press in the three-axis directions, specifically including the following steps: S34: Within any minimum resonance suppression period, based on the resonance frequencies of the press in the three axes, calculate the required suppression stiffness of the press in the three axes that matches the corresponding resonance frequencies. The calculation method of the required suppression stiffness is: Among them, k req To suppress the required stiffness, m is the mass of the mass block of the nonlinear dynamic vibration absorber, f dom is the resonant frequency of the press in the uniaxial direction; S35: The calculation method of the disc spring stiffness of the nonlinear dynamic vibration absorber is: Among them, k z is the disk spring stiffness of the nonlinear dynamic vibration absorber, E is the elastic modulus of the disk spring of the nonlinear dynamic vibration absorber, t is the thickness of the disk spring of the nonlinear dynamic vibration absorber, K1 is the geometric coefficient of the disk spring of the nonlinear dynamic vibration absorber, and D is the coil diameter of the disk spring of the nonlinear dynamic vibration absorber; S36: Establishing a pre-compression-stiffness relationship model of the disc spring of the nonlinear dynamic vibration absorber. The pre-compression-stiffness relationship model is expressed as: Among them, k base is the rigid reference parameter, β is the calibration coefficient, is the compression displacement of the disc spring of the nonlinear dynamic vibration absorber; By adjusting the pre-compression amount of the disc spring of the nonlinear dynamic vibration absorber, the disc spring stiffness of the nonlinear dynamic vibration absorber is made close to the required stiffness of the press. Therefore, the main controller controls the disc spring compression displacement adjustment instruction of the nonlinear dynamic vibration absorber as follows: 。 6. The method for suppressing low-frequency resonance of a press machine according to claim 5, wherein: During a single stamping action of the press, the main controller adjusts the vibration control efficiency of the nonlinear dynamic vibration absorber in several resonance suppression minimum cycles through a PID closed-loop feedback control method, specifically: the low-frequency resonance frequency of the press is defined as the set value of the PID control within a preset range, the low-frequency resonance frequency of the press after adjustment in each resonance suppression minimum cycle is the process variable of the PID control, and the difference between the set value and the process variable of the press after adjustment in each resonance suppression minimum cycle is the error of the PID control.

7. The method for suppressing low-frequency resonance of a press machine according to claim 1, wherein: The following steps are also included: S4: A resonance frequency alarm limit is set. When the three-axis acceleration sensor collects the vibration signal of the press and calculates that the resonance frequency of the press in the three-axis direction exceeds the resonance frequency alarm limit, the press stops the stamping operation and outputs an alarm signal.

8. A press low-frequency resonance suppression system, characterized in that: The method for suppressing low-frequency resonance of a press machine according to any one of claims 1 to 7 comprises: A press, comprising a body, a stamping slide assembly and a stamping platform; A three-axis acceleration sensor is used to measure the vibration signals of the press in the x-axis, y-axis and z-axis directions; A resonance suppression unit, the resonance suppression unit comprising nonlinear dynamic vibration absorbers distributed along the x-axis, y-axis, and z-axis, respectively, the resonance suppression unit being used to suppress low-frequency resonance of the press in the x-axis, y-axis, and z-axis directions; The three-axis acceleration sensor and the resonance suppression unit are each provided with four groups, which are respectively arranged at the four corners of the top of the crossbeam of the fuselage.

9. The press low-frequency resonance suppression system according to claim 8, characterized in that: The nonlinear dynamic vibration absorber includes a mass block, a slide rail, a nonlinear disc spring and a ball screw servo motor; The slide rail is extended along the height direction of the nonlinear dynamic vibration absorber, the mass block is slidably connected to the slide rail, the bottom of the mass block is provided with the nonlinear disc spring extended along the height direction of the nonlinear dynamic vibration absorber, the first end of the nonlinear disc spring abuts against the mass block, the ball screw servo motor is configured to drive the mass block to move, the mass block compresses the nonlinear disc spring, causing the nonlinear disc spring to produce a compressed displacement.

10. The press low-frequency resonance suppression system according to claim 9, characterized in that: Four groups of vertically arranged vibration isolators are respectively provided at the four corners of the bottom of the fuselage, and the vibration isolators are used to isolate the high-frequency vibration generated by the press during the stamping operation; The nonlinear dynamic vibration absorber also includes a damper, in which a silicon-based damping fluid is provided. The second end of the nonlinear disc spring abuts against the movable end surface of the damper. The damper is configured such that the ball screw servo motor drives the mass block to move, and the mass block compresses the nonlinear disc spring, causing the nonlinear disc spring to compress the silicon-based damping fluid inside the damper, thereby adjusting the vibration control performance of the nonlinear dynamic vibration absorber.

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