Electromagnetic energy harvesting type nonlinear variable damping shock absorber and control method thereof

Abstract

The invention relates to an electromagnetic energy harvesting type nonlinear variable damping shock absorber and a control method thereof. The electromagnetic energy harvesting type nonlinear variable damping shock absorber comprises a box body (1), a spring-mass damping mechanism (2) and an electromagnetic energy harvesting mechanism (3). The spring-mass damping mechanism (2) comprises a mass block (21) arranged on the guide rail (22) in a sliding mode, a nonlinear spring (23) arranged perpendicular to the movement direction of the mass block (21) and a linear spring (24) arranged parallel to the movement direction of the mass block (21). The electromagnetic energy harvesting mechanism (3) comprises a permanent magnet (31) and a coil (32) used for generating current when the permanent magnet (31) rotates. And a transmission mechanism (4) capable of converting translation of the mass block (21) into rotation of the permanent magnet (31) is arranged between the spring-mass damping mechanism (1) and the electromagnetic energy harvesting mechanism (2). Compared with the prior art, by controlling the resistance value change of the variable resistor (52), the balance between the vibration reduction performance and the energy harvesting efficiency of the system can be realized.

Description

Technical Field

[0001] The invention relates to the technical field of structural vibration reduction, and in particular to an electromagnetic energy-harvesting nonlinear variable damping vibration reducer and a control method thereof. Background Art

[0002] Most building structures will inevitably encounter various forms of vibration. Unnecessary vibration will not only reduce the stability and safety of the building structure, accelerate the fatigue aging of structural materials, shorten their service life, but also seriously affect people's daily life and health. Therefore, it is very important to achieve effective control of structural vibration. At the same time, with the development of intelligent building structures, due to the needs of structural vibration control and structural health monitoring, a large number of sensor networks are often deployed in the structure to capture structural status data. In view of the demand for continuous power supply of large-scale sensor networks, as well as the urgent need to reduce dependence on traditional energy and reduce operation and maintenance costs, it is also particularly important to explore sustainable energy supply solutions. To this end, design research on the integration of vibration reduction and energy capture has gradually emerged. However, the existing vibration reduction-energy capture system is based on linear resonance, and its performance is limited by the frequency of environmental vibration, making it difficult to maintain high efficiency in a highly random vibration environment.

[0003] Therefore, developing a new dual-function shock absorber that can simultaneously achieve efficient structural vibration control and energy capture has extremely broad application prospects. Summary of the invention

[0004] The purpose of the present invention is to provide an electromagnetic energy-harvesting nonlinear variable damping vibration absorber and a control method thereof. The vibration absorber is nonlinear, and the vibration damping frequency band and the energy-harvesting frequency band are broadened, so that efficient structural vibration control and energy capture can be achieved simultaneously.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] An electromagnetic energy-harvesting nonlinear variable damping shock absorber comprises a box body, a spring-mass damping mechanism and an electromagnetic energy-harvesting mechanism arranged on the box body;

[0007] The spring-mass damping mechanism comprises a mass block, a guide rail, a nonlinear spring, and a linear spring, wherein the mass block is slidably arranged on the guide rail, the nonlinear spring is arranged axially perpendicular to the movement direction of the mass block, and the linear spring is arranged axially parallel to the movement direction of the mass block;

[0008] The electromagnetic energy capture mechanism comprises a permanent magnet and a coil capable of generating current when the permanent magnet rotates;

[0009] A transmission mechanism capable of converting the translation of the mass block into the rotation of the permanent magnet is arranged between the spring-mass damping mechanism and the electromagnetic energy capturing mechanism.

[0010] Preferably, one end of the nonlinear spring is connected to the mass block, and the other end is connected to the box.

[0011] Preferably, one end of the linear spring is connected to the mass block, and the other end is connected to the box.

[0012] Preferably, the nonlinear spring is a spring with fixed stiffness or variable stiffness, and its initial state is pre-stressed or not pre-stressed, and the linear spring is a spring with fixed stiffness.

[0013] Preferably, one end of the guide rail is provided with a limiting member for preventing the mass block from escaping from the guide rail, and the other end is connected to the box.

[0014] Preferably, the transmission mechanism includes a gear-rack set, a fixed tube, a sliding tube, a fixed disk, and an end plate.

[0015] Preferably, one side of the end plate is connected to the mass block through an end plate connector, and the other side is connected to the sliding tube. The sliding tube is slidably connected to the fixed tube. The fixed tube is connected to the box body through a fixing device and a fixed tube connector. The gear-rack group is connected and fixed to the fixed tube through a fixing plate. The electromagnetic energy capture mechanism is connected to the fixed tube through a support member, and the gear-rack group is connected to the electromagnetic energy capture mechanism.

[0016] Further preferably, the relative positions of the fixed plate and the fixed tube are fixed and do not move with the sliding tube.

[0017] Further preferably, the sliding tube is provided with a groove for the fixed disk to pass through.

[0018] Preferably, the gear-rack set is arranged on a fixed plate through a support plate, and the gear set includes a first gear, a second gear, a third gear, a first rotating shaft, a second rotating shaft, and a rack.

[0019] Preferably, the first rotating shaft passes through the support plate, the first gear and the second gear are coaxially arranged with the first rotating shaft, the first gear is in contact with the rack, one end of the rack is connected to the end plate, and the other end passes through the fixed plate, the second rotating shaft passes through the fixed plate and is connected to the electromagnetic energy capturing mechanism, the second rotating shaft is coaxially arranged with the third gear, and the third gear is in vertical contact with the second gear.

[0020] Preferably, the radius of the first gear is smaller than the radius of the second gear, and the radius of the second gear is larger than the radius of the third gear, thereby greatly increasing the rotation speed of the rack transmission to the permanent magnet.

[0021] Preferably, the outer diameter of the sliding tube is smaller than or equal to the inner diameter of the fixed tube.

[0022] Preferably, the permanent magnet is coaxially arranged with the second rotating shaft, the coil is arranged around the permanent magnet, the axis of the coil coincides with the second rotating shaft, and there are multiple groups of the coil and the permanent magnet.

[0023] In the present invention, multiple groups of coils can be arranged around a single permanent magnet, and the multiple groups of coils are symmetrically arranged around the center of the permanent magnet to ensure the stability of the electromagnetic force.

[0024] Preferably, the mass block drives the end plate to move through the connecting piece, and the end plate slides along the axial direction of the fixed tube through the sliding tube. The rack can move along the axial direction with the end plate and drive the first gear to rotate. The first gear drives the first rotating shaft and the second gear to rotate at the same angular velocity. The second gear drives the third gear to rotate at the same linear velocity. The third gear drives the second rotating shaft to rotate at the same angular velocity. The rotation of the second rotating shaft drives the permanent magnet to rotate at the same angular velocity. The rotation of the permanent magnet causes the magnetic field to change, generates an induced electromotive force in the coil, and generates induced alternating current in the closed circuit.

[0025] Preferably, the coil is connected to an external circuit, and an induced current is generated in the coil when the permanent magnet rotates, and the induced current is alternating current.

[0026] Further preferably, the external circuit includes a rectifier for converting the alternating current in the coil into direct current, a variable resistor, a capacitor for collecting electric energy, and a control device for controlling the change in resistance of the variable resistor.

[0027] Further preferably, the rectifier is composed of a plurality of diodes connected in series and in parallel.

[0028] More preferably, the number of the capacitor is one or more.

[0029] Further preferably, the variable resistor is a thermistor, a photoresistor or other forms.

[0030] The present invention also provides a control method for the electromagnetic energy-harvesting nonlinear variable damping vibration absorber, which achieves a balance between the vibration reduction performance and the energy-harvesting efficiency of the system by controlling the change in the resistance value of the variable resistor. The control method is specifically as follows:

[0031] When the system's vibration reduction performance is poor and the energy capture efficiency is high, the control device controls the resistance of the variable resistor to decrease, so as to increase the induced current in the coil and enhance the electromagnetic induction effect, resulting in a corresponding increase in the surrounding magnetic field strength, thereby generating a greater resistance to the rotation of the permanent magnet. The reaction force of this resistance constitutes the damping force of the entire system, thereby enhancing the system's vibration reduction performance and reducing the system's energy capture efficiency;

[0032] When the system has good vibration reduction performance but poor energy capture efficiency, the control device controls the resistance of the variable resistor to increase, so as to reduce the induced current in the coil and weaken the electromagnetic induction effect. The magnetic field reduces the resistance to the rotation of the permanent magnet, and the vibration reduction performance of the system is reduced, thereby increasing the movement amplitude of the mass block and improving the energy capture efficiency. This weakens the vibration reduction performance of the system, improves the energy capture efficiency of the system, and achieves a balance between the overall vibration reduction performance and energy capture efficiency of the system.

[0033] The present invention aims to provide an electromagnetic energy-capturing nonlinear variable damping shock absorber, which can capture the mechanical energy of structural vibration and convert and store it into electrical energy, which can be used for structural health monitoring, sensor networks in structural vibration control systems or other low-power electronic equipment to power supply, thereby reducing operational energy consumption. In addition, the shock absorber uses nonlinear stiffness to broaden its vibration reduction frequency band and energy capture frequency band, and uses a variable nonlinear damping mechanism to achieve the best balance between the shock absorber's vibration reduction and energy capture performance, thereby simultaneously achieving the dual goals of efficient vibration control and energy capture of the shock absorber.

[0034] Conventional linear dampers have limitations in practical applications. Usually, the main structure has a first-order natural frequency ω1. Similarly, conventional linear tuned dampers also have a tuning frequency ω2, which is determined by the spring stiffness k and mass m of the damper (frequency calculation formula: ω2 = (k / m) 0.5 ). Among external excitations, the components with frequencies close to ω1, that is, components that easily cause resonance, have a significant impact on the main structure. Therefore, traditional designs often set the tuning frequency ω2 of the linear tuned damper to be close to the first-order natural frequency ω1 of the main structure in order to maximize the transfer of structural vibration energy to the damper. However, this design has an inherent defect: it only exhibits an effective vibration reduction effect for excitations with frequencies close to ω1. For linear energy harvesters, the principle is similar and they can only capture excitation energy with frequencies close to ω1.

[0035] The excitations faced by civil engineering structures are often random, and their energy is distributed in different frequency bands, such as natural phenomena such as earthquakes and wind loads. This randomness greatly reduces the vibration reduction effect of traditional linear dampers, because their narrow working frequency band limits their ability to cope with complex excitation environments. However, the electromagnetic energy-harvesting nonlinear variable damping shock absorber of the present invention does not have a constant damper stiffness k, but changes with the change of the excitation, resulting in its vibration reduction frequency ω2 also being dynamically adjusted accordingly (frequency calculation formula: ω2 = (k / m) 0.5 ). Compared with the traditional linear tuned damper, the electromagnetic energy harvesting nonlinear variable damping vibration absorber of the present invention exhibits a wider operating frequency band, so that it can more effectively cope with the complex and changeable excitation environment in the field of civil engineering.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] (1) The electromagnetic energy-harvesting nonlinear variable damping vibration absorber provided by the present invention has nonlinear stiffness characteristics. Compared with traditional passive linear vibration absorbers, it has achieved a significant expansion in the vibration reduction frequency band and energy-harvesting frequency band. At the same time, its vibration reduction performance and energy-harvesting efficiency are also greatly improved. The vibration absorber has stronger vibration reduction robustness and power supply stability, and is more suitable for complex and changeable vibration environments.

[0038] (2) In the present invention, the introduction of the variable resistor mechanism can flexibly adjust the optimal balance between the vibration reduction performance and the energy capture efficiency of the vibration absorber, and effectively avoid the disadvantages of insufficient vibration reduction performance or energy capture effect of the vibration absorber under certain working conditions; while ensuring basic vibration reduction, the vibration absorber also ensures the maximization of the energy capture efficiency, which is more conducive to achieving the dual goals of efficient vibration reduction and energy capture.

[0039] (3) The shock absorber of the present invention is a semi-active shock absorber. Even if the power is cut off under extreme working conditions, the shock absorber can still continue to function by relying on the passive control mechanism, effectively avoiding the potential risk of failure of traditional active shock absorbers due to power cuts under extreme working conditions.

[0040] (4) The shock absorber of the present invention is integrated with a spring-mass damping mechanism, an electromagnetic energy capture mechanism, a transmission mechanism, an external circuit and other parts, and has a high degree of modularization, which is conducive to mass production in practical applications, convenient installation and rapid maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a structural schematic diagram of the electromagnetic energy-harvesting nonlinear variable damping vibration absorber of the present invention;

[0042] Figure 2 for Figure 1 AA cross-sectional diagram of FIG.

[0043] Figure 3 for Figure 1 BB cross-section diagram;

[0044] Figure 4 It is a detailed structural diagram of the transmission mechanism of the present invention (side view);

[0045] Figure 5 Detailed structural diagram of the transmission mechanism of the present invention (top view);

[0046] Figure 6 A detailed structural diagram of the electromagnetic energy capture mechanism of the present invention;

[0047] Figure 7 is a cross-sectional view of the electromagnetic energy capture mechanism of the present invention;

[0048] Figure 8 A detailed structural diagram of the external circuit of the present invention;

[0049] Fig. 9 It is a schematic diagram of the structure of a conventional tuned mass damper of comparative example 1;

[0050] In all drawings, the same reference numerals are used to denote the same components or structures, wherein:

[0051] 1-box, 2-spring-mass damping mechanism, 21-mass block, 22-guide rail, 23-nonlinear spring, 24-linear spring, 25-limiting member, 3-electromagnetic energy capture mechanism, 31-permanent magnet, 32-coil, 4-transmission mechanism; 41-gear-rack group, 42-fixed tube, 43-sliding tube, 44-fixed disk, 45-end plate, 411-support plate, 412-first gear, 413-second gear, 414-third gear, 415-first rotating shaft, 416-second rotating shaft, 417-rack, 5-external circuit, 51-rectifier, 52-variable resistor, 53-capacitor, 54-control device, 6-end plate connector, 7-fixing device, 8-fixed tube connector, 9-support, 10-traditional tuned mass damper; 11-cylinder. DETAILED DESCRIPTION

[0052] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0053] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0054] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0055] In the following implementation manners or examples, unless otherwise specified, functional components or structures are conventional components or conventional structures used in the art to achieve corresponding functions.

[0056] Example 1

[0057] An electromagnetic energy-harvesting nonlinear variable damping vibration absorber, such as Figure 1 As shown, it includes a box body 1, in which a spring-mass damping mechanism 2 and an electromagnetic energy capture mechanism 3 are arranged; the spring-mass damping mechanism 2 includes a mass block 21 that can slide along a guide rail 22, a nonlinear spring 23 arranged perpendicular to the movement direction of the mass block 21, and a linear spring 24 arranged parallel to the movement direction of the mass block 21; the electromagnetic energy capture mechanism 3 includes a permanent magnet 31 and a coil 32, and when the permanent magnet 31 rotates, the coil 32 can generate an induced current; the present invention also includes a transmission mechanism 4 arranged between the spring-mass damping mechanism 1 and the electromagnetic energy capture mechanism 2, and the transmission mechanism 4 is used to convert the translational motion of the mass block 21 into the rotational motion of the permanent magnet 31.

[0058] Example 2

[0059] An electromagnetic energy-harvesting nonlinear variable damping vibration absorber, such as Figures 2 to 8 As shown, it includes a box body 1 and a spring-mass damping mechanism 2 and an electromagnetic energy capture mechanism 3 arranged on the box body 1.

[0060] The spring-mass damping mechanism 2 is composed of a mass block 21, a guide rail 22, a nonlinear spring 23 and a linear spring 24. The mass block 21 slides along the guide rail 22, and a limit member 25 is provided at one end of the guide rail 22 to prevent the mass block 21 from derailing, wherein the nonlinear spring 23 is connected to the mass block 21 perpendicular to the movement direction of the mass block 21, and the linear spring 24 is connected to the mass block 21 parallel to the movement direction of the mass block 21.

[0061] In this embodiment, the nonlinear spring 23 is a spring with fixed stiffness or variable stiffness, and its initial state is pre-stressed or not pre-stressed, and the linear spring 24 is a spring with fixed stiffness.

[0062] The electromagnetic energy-capturing mechanism 3 includes a permanent magnet 31 and a coil 32. The external circuit 5 includes a rectifier 51, a variable resistor 52, a capacitor 53 and a control device 54. The rectifier 51 is used to convert the alternating current in the coil 32 into direct current, the capacitor 53 can collect electric energy, and the control device 54 can control the resistance change of the variable resistor 52 to balance the vibration reduction performance and the energy-capturing efficiency.

[0063] A transmission mechanism 4 is provided between the spring-mass damping mechanism 2 and the electromagnetic energy capture mechanism 3. In this embodiment, the translational motion of the mass block 21 is converted into the rotational motion of the permanent magnet 31 through the transmission mechanism 4. The transmission mechanism 4 is composed of a gear-rack set 41, a fixed tube 42, a sliding tube 43, a fixed disk 44 and an end plate 45. One side of the end plate 45 is connected to the mass block 21 through an end plate connector 6, and the other side is connected to the sliding tube 43. A sliding connection is formed between the sliding tube 43 and the fixed tube 42, and the fixed tube 42 is fixed to the box 1 through a fixing device 7 and a fixed tube connector 8.

[0064] The gear-rack set 41 is arranged on the fixed disk 44 through the support plate 411, and the gear-rack set 41 includes a first gear 412, a second gear 413, a third gear 414, a first rotating shaft 415, a second rotating shaft 416 and a rack 417. Among them, the first rotating shaft 415 passes through the support plate 411 and is coaxially arranged with the first gear 412 and the second gear 413. The first gear 415 contacts the rack 417, one end of the rack 417 is connected to the end plate 45, and the other end passes through the fixed disk 44. The second rotating shaft 416 passes through the fixed disk 44, and the third gear 414 is in vertical contact with the second gear 413. The permanent magnet 31 is coaxially arranged with the second rotating shaft 416, and the coil 32 is arranged around the permanent magnet 31, and the axis of the coil 32 coincides with the second rotating shaft 416.

[0065] In this embodiment, the outer diameter of the sliding tube 43 is smaller than or equal to the inner diameter of the fixed tube 42, the radius of the first gear 412 is smaller than the radius of the second gear 413, the radius of the second gear 413 is larger than the radius of the third gear 414, and there are multiple groups of coils 32 and permanent magnets 31.

[0066] In this embodiment, the movement of the mass block 21 is transmitted to the end plate 45 through the connecting member 6, and the end plate 45 slides axially along the fixed tube 42 through the sliding tube 43. As the end plate 45 moves, the rack 417 also moves axially and causes the first gear 412 to rotate. This rotational motion is transmitted through the first rotating shaft 415, causing the second gear 413 to rotate at a synchronous angular velocity. Subsequently, the rotation of the second gear 413 drives the third gear 414 to rotate at a consistent linear velocity, and the rotation of the third gear 414 drives the permanent magnet 31 to rotate at the same angular velocity through the second rotating shaft 416. The rotation of the permanent magnet 31 causes the magnetic field around it to change, thereby inducing an electromotive force in the surrounding coil 32. When the circuit is closed, alternating current is generated therein.

[0067] This embodiment achieves a balance between the vibration reduction performance and the energy capture efficiency of the system by controlling the change in the resistance value of the variable resistor 52. The control method is as follows:

[0068] When the vibration reduction performance of the system is poor and the energy capture efficiency is high, the control device 54 controls the resistance of the variable resistor 52 to decrease, so as to increase the induced current in the coil 32 and enhance the electromagnetic induction effect, resulting in a corresponding increase in the surrounding magnetic field strength, thereby generating a greater resistance to the rotation of the permanent magnet 31. The reaction force of this resistance constitutes the damping force of the entire system, thereby enhancing the vibration reduction performance of the system and reducing the energy capture efficiency of the system.

[0069] When the system has good vibration reduction performance but poor energy capture efficiency, the control device 54 controls the resistance of the variable resistor 52 to increase, so as to reduce the induced current in the coil 32 and weaken the electromagnetic induction effect. The magnetic field reduces the resistance to the rotation of the permanent magnet 31, and the vibration reduction performance of the system is reduced, thereby increasing the movement amplitude of the mass block 21 and improving the energy capture efficiency, thereby weakening the vibration reduction performance of the system and improving the energy capture efficiency of the system, thereby achieving a balance between the overall vibration reduction performance and energy capture efficiency of the system.

[0070] Comparative Example 1

[0071] A conventional tuned mass damper 10 (TMD), such as Fig. 9 As shown, the damper is a linear damper, comprising a housing 1, a guide mechanism, a stiffness element, a mass block 21 and a damping element arranged in the housing 1. The guide mechanism is used to guide the mass block 21 to slide along a predetermined direction, and the guide mechanism is composed of two parallel guide rails 22, and the mass block 21 is slidably connected to the guide rails 22; the stiffness element is composed of a linear spring 24, which is arranged axially parallel to the movement direction of the mass block 21, and its two ends are respectively connected to the inner wall of the housing 1 and the mass block 21; the damping element is an oil cylinder 11, which is connected to the mass block 21 and the housing 1 through a connecting piece.

[0072] The preliminary simulation results show that under white noise excitation, the peak displacement and root mean square displacement of the single-degree-of-freedom structure of the conventional tuned mass damper are reduced by 6.66% and 17.39% respectively; the peak displacement and root mean square displacement of the single-degree-of-freedom structure of the electromagnetic energy-harvesting nonlinear variable damping vibration absorber of the present invention are reduced by 9.02% and 20.17% respectively. Compared with the conventional tuned mass damper, the vibration reduction performance of the electromagnetic energy-harvesting nonlinear variable damping vibration absorber of the present invention on the peak displacement and root mean square displacement of the structure is improved by 35.35% and 15.98% respectively.

[0073] In summary, the electromagnetic energy-harvesting nonlinear variable damping vibration absorber of the present invention has a broadened vibration-damping frequency band and an energy-harvesting frequency band, and can simultaneously achieve efficient structural vibration control and energy capture.

[0074] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. An electromagnetic energy harvesting type nonlinear variable damping vibration absorber, characterized in that: It comprises a box body (1), and a spring-mass damping mechanism (2) and an electromagnetic energy capture mechanism (3) arranged on the box body (1); The spring-mass damping mechanism (2) comprises a mass block (21), a guide rail (22), a nonlinear spring (23), and a linear spring (24); the mass block (21) is slidably arranged on the guide rail (22); the nonlinear spring (23) is arranged axially perpendicular to the movement direction of the mass block (21); and the linear spring (24) is arranged axially parallel to the movement direction of the mass block (21); The electromagnetic energy capture mechanism (3) comprises a permanent magnet (31) and a coil (32) capable of generating current when the permanent magnet (31) rotates; A transmission mechanism (4) capable of converting the translation of the mass block (21) into the rotation of the permanent magnet (31) is provided between the spring-mass damping mechanism (1) and the electromagnetic energy capturing mechanism (3).

2. The electromagnetic energy harvesting type nonlinear variable damping vibration absorber according to claim 1, characterized in that: One end of the nonlinear spring (23) is connected to the mass block (21), and the other end is connected to the box (1); One end of the linear spring (24) is connected to the mass block (21), and the other end is connected to the box (1).

3. The electromagnetic energy harvesting type nonlinear variable damping vibration absorber according to claim 2, characterized in that: The nonlinear spring (23) is a spring with fixed stiffness or variable stiffness, and its initial state is pre-stressed or not pre-stressed, and the linear spring (24) is a spring with fixed stiffness.

4. The electromagnetic energy harvesting type nonlinear variable damping vibration absorber according to claim 1, characterized in that: One end of the guide rail (22) is connected to the box body (1), and the other end is provided with a limiting member (25) for preventing the mass block (21) from falling off the guide rail (22).

5. The electromagnetic energy harvesting type nonlinear variable damping vibration absorber according to claim 1, characterized in that: The transmission mechanism (4) comprises a gear-rack set (41), a fixed tube (42), a sliding tube (43), a fixed disk (44), and an end plate (45); One side of the end plate (45) is connected to the mass block (21) via an end plate connector (6), and the other side is connected to a sliding tube (43). The sliding tube (43) is slidably connected to a fixed tube (42). The fixed tube (42) is connected to the housing (1) via a fixing device (7) and a fixed tube connector (8). The gear-rack set (41) is connected to the fixed tube (42) via a fixing plate (44). The electromagnetic energy capture mechanism (3) is connected to the fixed tube (42) via a supporting member (9). The gear-rack set (41) is connected to the electromagnetic energy capture mechanism (3).

6. The electromagnetic energy harvesting type nonlinear variable damping vibration absorber according to claim 5, characterized in that: The gear-rack set (41) is arranged on a fixed plate (44) via a support plate (411), and the gear set (41) comprises a first gear (412), a second gear (413), a third gear (414), a first rotating shaft (415), a second rotating shaft (416), and a rack (417); The first rotating shaft (415) passes through the support plate (411); the first gear (412) and the second gear (413) are coaxially arranged with the first rotating shaft (415); the first gear (412) contacts with a rack (417); one end of the rack (417) is connected to the end plate (45) and the other end passes through the fixed plate (44); the second rotating shaft (416) passes through the fixed plate (44) and is connected to the electromagnetic energy capture mechanism (3); the second rotating shaft (416) and the third gear (414) are coaxially arranged; the third gear (414) and the second gear (413) are in vertical contact.

7. The electromagnetic energy harvesting type nonlinear variable damping vibration absorber according to claim 6, characterized in that: The radius of the first gear (412) is smaller than the radius of the second gear (413), and the radius of the second gear (413) is larger than the radius of the third gear (414); the outer diameter of the sliding tube (43) is smaller than or equal to the inner diameter of the fixed tube (42).

8. The electromagnetic energy harvesting type nonlinear variable damping vibration absorber according to claim 6, characterized in that: The permanent magnet (31) is coaxially arranged with the second rotating shaft (416), the coil (32) is arranged around the permanent magnet (31), the axis of the coil (32) coincides with the second rotating shaft (416), and there are multiple groups of the coil (32) and the permanent magnet (31).

9. The electromagnetic energy harvesting type nonlinear variable damping vibration absorber according to claim 1, characterized in that: The coil (32) is connected to an external circuit (5), and when the permanent magnet (31) rotates, an induced current is generated in the coil (32), and the induced current is alternating current; The external circuit (5) comprises a rectifier (51) for converting the alternating current in the coil (32) into direct current, a variable resistor (52), a capacitor (53) for collecting electric energy, and a control device (54) for controlling the change in resistance of the variable resistor (52).

10. A control method for an electromagnetic energy harvesting type nonlinear variable damping vibration absorber according to any one of claims 1 to 9, characterized in that: By controlling the change in resistance of the variable resistor (52), a balance between the vibration reduction performance and the energy capture efficiency of the system is achieved. The specific control method is as follows: When the vibration reduction performance of the system is poor and the energy capture efficiency is high, the control device (54) controls the resistance of the variable resistor (52) to decrease, so as to increase the induced current in the coil (32), enhance the electromagnetic induction effect, and cause the surrounding magnetic field strength to increase accordingly, thereby generating a greater resistance to the rotation of the permanent magnet (31). The reaction force of this resistance constitutes the damping force of the entire system, thereby enhancing the vibration reduction performance of the system and reducing the energy capture efficiency of the system; When the vibration reduction performance of the system is good but the energy capture efficiency is poor, the control device (54) controls the resistance value of the variable resistor (52) to increase, so as to reduce the induced current in the coil (32), weaken the electromagnetic induction effect, reduce the obstruction of the magnetic field on the rotation of the permanent magnet (31), reduce the vibration reduction performance of the system, and further increase the movement amplitude of the mass block (21), thereby improving the energy capture efficiency, thereby weakening the vibration reduction performance of the system, improving the energy capture efficiency of the system, and achieving a balance between the overall vibration reduction performance and the energy capture efficiency of the system.

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