A multi-stable electromagnetic energy-harvesting vibration absorber

Abstract

The application discloses a multi-stable electromagnetic energy capturing vibration absorber, and belongs to the field of vibration suppression and energy capturing. The multi-stable electromagnetic energy capturing vibration absorber comprises a nonlinear vibration suppression device and an electromagnetic multi-stable energy capturing oscillator installed thereon. The nonlinear vibration suppression device is designed based on the technical principle of a quasi-zero stiffness vibration isolator, multi-stable motion is realized through the structural design of the electromagnetic multi-stable energy capturing oscillator, and the vibration energy capturing performance is further improved. The problems that the existing vibration isolation-energy capturing integrated device can only realize single-stable small-amplitude oscillation, vibration energy cannot be fully converted, the potential well width is limited, and large-amplitude motion cannot be realized under low-frequency conditions are solved.

Description

Technical Field

[0001] This invention relates to the field of vibration suppression and energy capture, specifically to a multistable electromagnetic energy capture vibration absorber, used to achieve multistable oscillations, suppress vibration, and convert some vibration energy into electrical energy. Background Technology

[0002] Vibration is ubiquitous in nature and is a double-edged sword. On the one hand, vibration can transmit energy and information; on the other hand, it can cause structural fatigue, loosening of parts, and even structural damage, negatively impacting production and daily life. Therefore, vibration control and application have become a hot research area today.

[0003] Traditional linear vibration isolators, due to their high natural frequencies, struggle to suppress low-frequency or even ultra-low-frequency vibrations. Therefore, researchers have proposed quasi-zero stiffness vibration isolators. Quasi-zero stiffness isolators possess both low and high dynamic stiffness, along with excellent load-bearing capacity and a low natural frequency, enabling them to suppress low-frequency and even ultra-low-frequency vibrations. However, quasi-zero stiffness isolators exhibit resonance peaks in the low-frequency range, which can cause large-amplitude vibrations in the structure within a certain frequency range, leading to damage or detachment of the protected structure and potentially causing dangerous accidents. Furthermore, quasi-zero stiffness isolators exhibit unstable multi-value ranges in the low-frequency range, which can also negatively impact the protected equipment or structures. Additionally, traditional quasi-zero stiffness isolators are generally structurally complex, and some require external energy support, resulting in high production costs and significant manufacturing challenges.

[0004] Vibration energy can be captured to power devices such as microelectromechanical sensors, reducing their dependence on external power sources. However, most existing energy harvesters that capture vibration energy through electromagnetic conversion generally have limited applications and cannot achieve vibration suppression.

[0005] The design of an integrated vibration isolation and energy harvesting device, combining vibration energy harvesters and isolators, has attracted considerable attention. However, existing traditional quasi-zero stiffness integrated vibration isolation and energy harvesting devices can only achieve monostable small-amplitude oscillations, failing to adequately balance the device's vibration isolation and energy harvesting performance. This results in insufficient energy conversion during vibration, limited potential well width, and an inability to achieve large-amplitude motion under low-frequency conditions.

[0006] Therefore, there is a need to provide a multistable electromagnetic energy-harvesting vibration absorber that can both harvest energy from multistable oscillations and suppress low-frequency vibrations, in order to solve the above problems. Summary of the Invention

[0007] To overcome the shortcomings of existing technologies, this invention provides a multistable electromagnetic energy-harvesting vibration absorber. Based on the principle of quasi-zero stiffness vibration isolators, a nonlinear vibration suppression device is designed. A matching electromagnetic multistable energy-harvesting oscillator (a nonlinear oscillator) is installed on this nonlinear vibration suppression device. Vibration suppression is achieved through the nonlinear vibration suppression device, and a portion of the vibration energy is converted into electrical energy through the electromagnetic multistable energy-harvesting oscillator. The two work synergistically to form a nonlinear energy sink, achieving the effect of attenuating resonance peaks and shortening the unstable multi-value range. Furthermore, the structural design of the electromagnetic multistable energy-harvesting oscillator enables multistable motion, further improving the vibration energy harvesting performance.

[0008] The technical solution of the present invention is: a multistable electromagnetic energy harvesting vibration absorber, comprising: a nonlinear vibration suppression device and an electromagnetic multistable energy harvesting oscillator installed on the nonlinear vibration suppression device, wherein the nonlinear vibration suppression device is used to suppress vibration and transmit vibration energy to the electromagnetic multistable energy harvesting oscillator, and the electromagnetic multistable energy harvesting oscillator is used to convert vibration energy into electrical energy to supply electrical equipment.

[0009] The nonlinear vibration suppression device is a quasi-zero stiffness structure, which includes a main frame, a moving frame installed inside the main frame, and the moving frame and the main frame are elastically connected by a vertical spring assembly and a horizontal spring assembly. The moving frame is also vertically slidably connected to the main frame by a vertical slide rail assembly.

[0010] The electromagnetic multistable energy-harvesting oscillator includes two end caps arranged vertically opposite each other, referred to as the upper end cap and the lower end cap. A plastic tube is vertically installed between the two end caps, and an optical axis is coaxially inserted inside the plastic tube. The optical axis passes through the upper end cap, and a counterweight is installed at its end outside the upper end cap, while a moving magnet is installed at its end inside the plastic tube. The optical axis and the upper end cap are slidably connected. End magnets are installed on the opposite surfaces of the two end caps, and the end magnets are located inside the plastic tube. A coil is wound around the outside of the plastic tube, and the coil is connected to an external power supply device. Two annular magnets are coaxially sleeved outside the plastic tube, and the two annular magnets are installed between the two end caps through a screw mounting assembly. The lower end cap of the plastic tube is installed on a moving frame. When the moving frame vibrates, the moving magnets move between the two end magnets, the magnetic flux of the coil changes, and a current is generated to supply power to the electrical equipment.

[0011] A further technical solution of the present invention is as follows: the horizontal spring assembly includes a horizontal guide rail, which is installed inside the frame of the motion frame and extends horizontally through the motion frame. Two horizontal sliders are slidably installed on the horizontal guide rail, and a connector is installed on each horizontal slider. The two connectors face each other and are elastically connected by a horizontal spring. The end of the connector facing away from the horizontal spring is hinged to the main frame via a connecting rod. One end of the connecting rod is hinged to the connector, and the other end is hinged to the main frame.

[0012] A further technical solution of the present invention is: the motion frame is a hollow frame structure, which does not restrict the displacement of the two connecting parts along the horizontal guide rail; a load-bearing platform is fixedly installed on the upper end face of the motion frame, and an electromagnetic multi-stable energy-harvesting oscillator is installed on the load-bearing platform.

[0013] A further technical solution of the present invention is as follows: the main frame is an irregular frame structure, including a bottom plate, two side plates and a back plate. The two side plates are symmetrically installed at both ends of the back plate, and the back plate is installed on the bottom plate. The side plates are provided with mounting ears on their inner sides. Multiple mounting holes are provided horizontally in a straight line on the mounting ears. Pins are inserted through the mounting holes and are used for hinged connection between the connecting rod and the main frame. The distance between the connecting rods on both sides can be adjusted by adjusting the hole positions when the connecting rod and the main frame are hinged.

[0014] A further technical solution of the present invention is: the vertical slide rail assembly includes a vertical guide rail, the vertical guide rail and the horizontal guide rail are spatially perpendicular, and it is installed on the inner side of the back plate of the main frame. A vertical slider is slidably installed on the vertical guide rail, and the vertical slider is fixedly connected to the side wall of the moving frame; when the moving frame vibrates, it moves up and down along the vertical guide rail with the vertical slider.

[0015] A further technical solution of the present invention is: the vertical spring assembly includes a vertical spring, the lower end of the vertical spring is fixedly connected to the main frame through a set of fastening connectors, and the upper end of the vertical spring is fixedly connected to the lower end face of the motion frame through another set of fastening connectors.

[0016] A further technical solution of the present invention is as follows: the end cap is made of plastic, and two coaxial annular protrusions are provided in the middle of one side of the end cap. The inner annular protrusion is higher than the outer annular protrusion. The center of the inner annular protrusion is provided with a through hole along the axial direction. The annular protrusions of the two end caps are opposite to each other. The two ends of the plastic tube are respectively embedded in the gap between the corresponding two annular protrusions and glued and fixed. The outer diameter of the inner annular protrusion is in contact with the inner diameter of the plastic tube. The end magnet is fixedly installed on the end face of the inner annular protrusion.

[0017] A further technical solution of the present invention is: a linear bearing is installed in the through hole of the upper end cover, the optical axis is inserted into the linear bearing, and the linear bearing is used for sliding connection between the optical axis and the upper end cover.

[0018] A further technical solution of the present invention is as follows: the lead screw mounting assembly includes two lead screws and multiple acrylic plates. The two lead screws are fixedly connected between two end caps and are parallel and equidistant from the plastic tube. Each annular magnet is clamped and fixed by two upper and lower acrylic plates. The two ends of the acrylic plates are respectively fitted onto the two lead screws and their installation positions are locked by fasteners. The center of the acrylic plate is provided with a through hole for fitting onto the outside of the plastic tube. The installation positions of the two annular magnets in the axial direction of the lead screws are adjustable.

[0019] A further technical solution of the present invention is that the magnetic poles of the two end magnets are in the same direction, with the north pole pointing upwards and the south pole pointing downwards; the magnetic poles of the moving magnet and the two ring magnets are in the same direction, and are opposite to the magnetic poles of the end magnets.

[0020] The beneficial effects of the present invention are as follows: The present invention provides a multistable electromagnetic energy trapping vibration absorber, which is a combined device with vibration suppression and vibration energy capture and conversion into electrical energy. In this device, the nonlinear vibration suppression device achieves vibration suppression and transfers the vibration energy to the electromagnetic multistable energy trapping oscillator, which then converts part of the vibration energy into electrical energy.

[0021] This application utilizes the principle of quasi-zero stiffness vibration isolators to design a nonlinear vibration suppression device. In this device, the moving frame and the main frame are elastically connected via vertical and horizontal spring assemblies. The moving frame is also vertically slidably connected to the main frame via a vertical slide rail assembly. The vertical spring assembly provides positive stiffness to the nonlinear vibration suppression device, while the horizontal spring assembly provides negative stiffness. Together, the vertical and horizontal spring assemblies form a quasi-zero stiffness. To avoid the resonance peaks and unstable multi-value ranges inherent in quasi-zero stiffness vibration isolators, an electromagnetic multi-stable energy-harvesting oscillator is designed and installed on the nonlinear vibration suppression device to form a nonlinear energy sink, thereby attenuating resonance peaks and shortening the unstable multi-value range. The nonlinear energy sink enables targeted transfer of vibration energy, achieving optimal vibration isolation performance while maximizing energy harvesting.

[0022] This application utilizes the structural design of an electromagnetic multistable energy-harvesting oscillator to achieve multistable motion, further improving vibration energy harvesting performance. The oscillator slides vertically through a plastic tube, with a moving magnet installed at the end of the optical axis inside the tube. End magnets are located at both ends of the plastic tube. A coil is wound around the outer wall of the tube and fitted with two ring magnets. By adjusting the orientation of each magnet and its poles, when the electromagnetic multistable energy-harvesting oscillator vibrates up and down with the moving frame, the optical axis moves vertically, causing the moving magnets to move vertically, resulting in a change in the magnetic flux in the coil and the generation of current. During operation, the multistable energy-harvesting oscillator achieves tristable motion, generating large-amplitude multistable oscillations and achieving efficient conversion of vibration energy. By adjusting the installation positions of the two ring magnets and the distance between them, the potential well width can be varied to adapt to different external excitation conditions, achieving tristable oscillation and thus improving energy harvesting efficiency.

[0023] The overall manufacturing process of this structure is simple and easy to commercialize. It can simultaneously achieve vibration suppression and energy capture, protecting the equipment it houses while supplying power to some microelectromechanical sensors and other electrical devices. It has broad application prospects in aerospace, rail transportation, machining, offshore wind power and other fields. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a front view of the overall structure of a multistable electromagnetic energy trapping vibration absorber according to the present invention;

[0026] Figure 2 This is a left view of the overall structure of a multistable electromagnetic energy trapping vibration absorber according to the present invention;

[0027] Figure 3 This is a top view of the overall structure of a multistable electromagnetic energy trapping vibration absorber according to the present invention;

[0028] Figure 4 This is a rear view of the overall structure of a multistable electromagnetic energy trapping vibration absorber according to the present invention;

[0029] Figure 5 This is a schematic diagram illustrating the installation method and magnet arrangement of the electromagnetic multistable energy-harvesting oscillator in this invention.

[0030] Figure 6 This is a schematic diagram of the linear bearing installed on the upper end cover of the present invention;

[0031] Figure 7 This is a schematic diagram of the nonlinear vibration suppression device in this invention (to show the internal structure, half of the support platform, part of the moving frame, and a connecting rod are hidden in the figure).

[0032] Figure 8 This is a schematic diagram showing the installation relationship of the main frame, vertical guide rail, and pin shaft in this invention;

[0033] Figure 9 This is a schematic diagram showing the installation position relationship between the motion frame and the vertical slider in this invention;

[0034] Figure 10 This is a schematic diagram showing the installation positional relationship of the motion frame, support platform, horizontal guide rail, vertical spring, and vertical slider in this invention;

[0035] Figure 11 This is a schematic diagram illustrating the connection between the vertical spring and the motion frame in this invention;

[0036] Figure 12 This is a schematic diagram showing the installation position relationship of the horizontal spring, horizontal guide rail, horizontal slider, connector, clamping plate, connecting rod, and pin in this invention (one connecting rod is hidden in the figure).

[0037] Figure 13 This is the phase diagram of the electromagnetic multistable energy-harvesting oscillator in this invention;

[0038] Figure 14 A comparison of the amplitude-frequency curves of the nonlinear vibration suppression device with and without an electromagnetic multistable energy-harvesting oscillator;

[0039] Figure 15 The experimental results of the multistable electromagnetic energy trapping vibration absorber of this invention are shown in the figure.

[0040] In the diagram: 1. Electromagnetic multi-stable energy-harvesting oscillator; 11. Counterweight; 12. Optical axis; 13. End magnet; 14. Acrylic plate; 15. Ring magnet; 16. Moving magnet; 17. Coil; 18. Lead screw; 19. Plastic tube; 110. Upper end cover; 111. Lower end cover; 112. Linear bearing; 113. Inner annular boss; 114. Outer annular boss; 2. Nonlinear vibration suppression device; 21. Main frame; 22. Vertical 23. Guide rail, 24. Support platform, 25. Vertical slider, 26. Horizontal spring, 27. Connector, 28. Linkage rod, 29. Horizontal slider, 20. Horizontal guide rail, 210. Fixed rod, 211. Moving frame, 212. Vertical spring, 213. Clamping plate, 214. Pin, 215. Slide groove, 216. Mounting hole, 217. Smooth hole, 218. Base plate, 219. Side plate, 220. Back plate, 221. Mounting ear, 222. Assembly hole. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] An embodiment of the multistable electromagnetic energy trapping vibration absorber of the present invention, such as... Figure 1-4As shown, the device includes an electromagnetic multistable energy-harvesting oscillator 1 and a nonlinear vibration suppression device 2. This structure can simultaneously achieve vibration suppression and energy harvesting. The nonlinear vibration suppression device 2 is a quasi-zero stiffness structure used for vibration suppression and transferring vibration energy to the electromagnetic multistable energy-harvesting oscillator 1. The electromagnetic multistable energy-harvesting oscillator 1 is mounted on the nonlinear vibration suppression device 2 and has an electromagnetic conversion function, used to convert vibration energy into electrical energy to supply electrical equipment. This solves the problem that existing traditional quasi-zero stiffness vibration isolation and energy harvesting integrated devices can only achieve monostable small-amplitude oscillations, and cannot well balance the vibration isolation and energy harvesting performance of the device, resulting in insufficient conversion of vibration energy, limited potential well width, and inability to achieve large-amplitude motion under low-frequency conditions.

[0043] like Figures 7-12 As shown, the nonlinear vibration suppression device 2 mainly includes a main frame 21, a motion frame 211, a vertical spring assembly, a horizontal spring assembly, and a vertical slide rail assembly.

[0044] The main frame 21, serving as the main support component of the device, is an irregular frame structure. (See reference...) Figure 8 It includes a base plate 218, two side plates 219, and a back plate 220. The two side plates 219 are symmetrically mounted at both ends of the back plate 220, which is mounted on the base plate 218. The two side plates 219 and the back plate 220 form a three-sided enclosure above the base plate 218, together with the base plate 218, forming the installation space within the main frame 21 for installing the remaining components of the nonlinear vibration suppression device 2. The inner side of the side plates 219 is provided with mounting ears 221, and the mounting ears 221 are provided with multiple horizontal mounting holes 216 for connecting with the horizontal spring assembly.

[0045] The moving frame 211 is elastically connected to the main frame 21 via a vertical spring assembly and a horizontal spring assembly. The moving frame 211 is also vertically slidably connected to the main frame 21 via a vertical slide rail assembly. The vertical spring assembly provides positive stiffness for the nonlinear vibration suppression device, while the horizontal spring assembly provides negative stiffness. Together, the vertical and horizontal spring assemblies form a quasi-zero stiffness. The vertical slide rail assembly provides sliding track support for the moving frame 211 during elastic vibration, thus defining the direction of movement of the moving frame 211.

[0046] For details, please refer to Figure 10 , Figure 7 The motion frame 211 is a hollow frame structure with a square shape. It is located on the base plate 218 inside the main frame 21. The bottom of the motion frame 211 is elastically connected to the base plate 218 through a vertical slide rail assembly, and is also elastically connected to the side plates 219 on both sides through a horizontal spring assembly that runs through the motion frame 211.

[0047] The horizontal spring assembly mainly includes a horizontal guide rail 29, two horizontal sliders 28, two connecting pieces 26, a horizontal spring 25, four connecting rods 27, two clamping plates 213, four pins 214, and multiple nuts. The horizontal guide rail 29 is installed inside the frame of the motion frame 211 and is fixedly connected to the bottom wall of the motion frame 211, and horizontally passes through the motion frame 211. The two horizontal sliders 28 are slidably installed on the horizontal guide rail 29. Each horizontal slider 28 is equipped with a connecting piece 26, and the two connecting pieces 26 face each other. A horizontal spring 25 is installed between the two connecting pieces 26. One end of the horizontal spring 25 is fixedly connected to one side of the connecting piece 26, and the other end of the horizontal spring 25 is fixedly connected to the other side of the connecting piece 26. The connection structures at both ends of the horizontal spring 25 and the connecting piece 26 are the same, both connected by a clamping plate 213 and two sets of bolts and nuts. The clamping plate 213 is inserted perpendicularly to the axial direction of the horizontal spring 25 into the inner side of the end ring at the end of the horizontal spring 25. The through holes at both ends of the clamping plate 213 are aligned with the corresponding threaded holes on the connecting piece 26. The clamping plate 213 and the connecting piece 26 are fixed by bolts and nuts, realizing the elastic connection of the two connecting pieces 26 through the horizontal spring 25. The ends of the two connecting pieces 26 facing away from the horizontal spring 25 are both hinged to the main frame 21 by a connecting rod 27. A pin 214 is installed at the end of the connecting piece 26 facing away from the horizontal spring 25. A pin 214 is also installed in the mounting hole 216 of the mounting ear 221. One end of the connecting rod 27 is hinged to the pin 214 of the connecting piece 26, and the other end is hinged to the pin 214 of the mounting hole 216 of the main frame 21, so as to ensure that the connecting rod 27 can rotate freely. To achieve motion stability, two connecting rods 27 are provided on the same side, clamping the connecting piece 26 and the mounting ear 221 between the two connecting rods 27. External threads are provided at both ends of the pin 214, and the connecting rods 27 are locked with nuts after installation to prevent them from falling off. The horizontal spring assembly provides negative stiffness for the nonlinear vibration suppression device 2. The hollow structure of the motion frame 211 does not restrict the movement of the two connecting pieces 26 along the horizontal guide rail 29.

[0048] Since the mounting ears 221 have three horizontally aligned mounting holes 216, the distance between the two connecting rods 27 can be adjusted by connecting the connecting rods 27 to different mounting holes 216, thereby changing the structural parameters and achieving near-zero stiffness under different working conditions. It should be noted that the connecting rods 27 on both sides are symmetrically installed relative to the horizontal spring 25. The hollow structure of the motion frame 211 does not affect the displacement of the two connecting parts 26 along the horizontal guide rail. A load-bearing platform 23 is fixedly installed on the upper end face of the motion frame 211 for mounting the electromagnetic multistable energy-harvesting oscillator 1.

[0049] like Figure 7 , Figure 10 , Figure 11As shown, the vertical spring assembly includes a vertical spring 212 and two sets of fastening connectors. The fastening connectors include a clamping plate 213 and a bolt and nut assembly. The vertical spring 212 is perpendicular to the horizontal spring 25. The lower end of the vertical spring 212 is fixedly connected to the base plate 218 of the main frame 21 via the clamping plate 213 and the bolt and nut assembly. The upper end of the vertical spring 212 is fixedly connected to the lower end face of the moving frame 211 via another clamping plate 213 and the bolt and nut assembly. The two ends of the vertical spring 212 are fixedly installed in the same way: the clamping plate 213 is inserted axially into the inner side of the end ring of the vertical spring 212, perpendicular to its axis, and then fastened to the clamping plate 213 and the connected component (base plate 218 or moving frame 211) via bolts and nuts. The vertical spring 212 generates positive stiffness for the nonlinear vibration suppression device 2. The horizontal spring assembly and the vertical spring assembly together form quasi-zero stiffness.

[0050] like Figure 7-9 As shown, the vertical slide rail assembly includes a vertical guide rail 22 and a vertical slider 24. The vertical guide rail 22 and the horizontal guide rail 29 are spatially perpendicular. The vertical slide rail 22 is installed on the inner side of the back plate 220 of the main frame 21. The vertical slide rail 22 has multiple mounting holes. Bolts are passed through the mounting holes of the vertical slide rail 22 and the slide grooves 215 provided in the back plate 220 in sequence, and locked with nuts to fix the vertical guide rail 22 and the main frame 21. The vertical slider 24 is slidably installed on the vertical guide rail 22 and can move up and down along the vertical guide rail 22. The vertical slider 24 is fixedly connected to the side wall of the moving frame 211 by screws. When the moving frame 211 vibrates, it will move up and down along the vertical guide rail 22 with the vertical slider 24. The side wall of the motion frame 211 has eight holes for connecting with the vertical slider 24. Four adjacent holes can be selected to fix the vertical slider 24 as needed. By selecting different upper and lower connecting holes, the compression of the vertical spring 212 can be adjusted to accommodate different loads and thus adjust the vibration parameters. The vertical slide rail assembly restricts the motion frame 211 to move only up and down along the vertical guide rail 22.

[0051] like Figure 1 , Figure 5 , Figure 6 As shown, the electromagnetic multistable energy-harvesting oscillator 1 is installed on the nonlinear vibration suppression device 2 to convert vibration energy into electrical energy to supply electrical equipment.

[0052] The electromagnetic multistable energy-harvesting oscillator 1 includes two end caps, a plastic tube 19, an optical axis 12, a linear bearing 112, a counterweight 11, a moving magnet 16, two end magnets 13, two annular magnets 15, four acrylic plates 14, two lead screws 18, and multiple nuts. The two end caps have identical structures and are positioned opposite each other. The one located at the upper end is designated as the upper end cap 110, and the one located at the lower end is designated as the lower end cap 111. The end caps are made of plastic, and each end cap has two coaxial annular bosses in the middle of one side. The inner annular boss 113 is higher than the outer annular boss 114. The center of the inner annular boss has an axial through hole. The annular bosses of the two end caps face each other and are used to install the plastic tube 19. The plastic tube 19 is vertically installed between the two end caps. Both ends of the plastic tube 19 are embedded in the gaps between the corresponding two layers of annular bosses and glued in place. The outer diameter of the inner annular boss 113 contacts the inner diameter of the plastic tube 19.

[0053] A linear bearing 112 is installed in the through hole of the upper end cover 110. The optical axis 12 passes through the linear bearing 112, with one end of the optical axis 12 extending into the plastic tube 19 and the other end located outside the upper end cover 110. The optical axis 12 and the upper end cover 110 are slidably connected by the linear bearing 112. A counterweight 11 is installed at the end of the optical axis 12 outside the upper end cover 110, and a moving magnet 16 is installed at the end of the optical axis 12 inside the plastic tube 19. End magnets 13 are glued to the end faces of the annular bosses 113 in the inner layers of both end covers, and the end magnets 13 are located inside the plastic tube 19. The end magnets 13 are annular, allowing the optical axis 12, which passes through the upper end cover 110, to pass through the central hole of the end magnet 13 installed in the upper end cover 110.

[0054] A coil 17 is wound around the outer wall of a plastic tube 19, and the coil 17 is connected to an external power supply. Two annular magnets 15 are coaxially sleeved on the outside of the plastic tube 19, and the two annular magnets 15 are mounted between two end caps via a screw mounting assembly. Specifically, the screw mounting assembly includes two screws 18, four acrylic plates 14, and multiple nuts. The two screws 18 are fixedly connected between the two end caps and are parallel and equidistant from the plastic tube 19. The screws 18 have external threads, and both ends are fixedly connected to the end caps by two nuts. The end caps have through holes for connecting the screws 18. Each annular magnet 15 is clamped and fixed by two upper and lower acrylic plates 14, which are fixed and clamped by bolts and nuts. The acrylic plates 14 have through holes at both ends corresponding to the screws 18 on both sides, and the installation height of the acrylic plates 14, that is, the installation height of the annular magnet 15 along the axial direction of the screws 18, is locked by the upper and lower nuts. The acrylic plate 14 has a through hole in its center for fitting onto the plastic tube 19. By loosening the nut locking the acrylic plate 14, the axial mounting position of the annular magnet 15 on the lead screw 18 can be adjusted, thereby adjusting the distance between the two annular magnets 15. Adjusting the mounting position of the annular magnets 15 allows for variations in the potential well width to adapt to different external excitation conditions, enabling the electromagnetic multistable energy-harvesting oscillator 1 to achieve multistable large-amplitude oscillations and improving energy harvesting performance.

[0055] The lower end cap 111 is horizontally placed on the support platform 23 and in contact with the surface of the support platform 23. Two optical holes 217 are provided on the support platform 23 corresponding to the positions of the two lead screws 18. The lower ends of the two lead screws 18 pass through the corresponding optical holes 217 on the support platform 23 and are locked in place by nuts. This achieves a fixed connection between the electromagnetic multistable energy harvesting oscillator 1 and the nonlinear vibration suppression device 2.

[0056] The magnetic pole orientations of each magnet in the electromagnetic multistable energy-harvesting oscillator 1 are set as follows: Figure 5 As shown, the magnetic poles of the two end magnets 13 are in the same direction, with the north pole pointing upwards and the south pole pointing downwards. The magnetic poles of the moving magnet 16 are in the same direction as those of the two ring magnets 15, with the north pole pointing downwards and the south pole pointing upwards. This magnetic pole orientation enables the electromagnetic multistable energy-harvesting oscillator 1 to form a tristable motion during operation, generating multistable large-amplitude oscillations and achieving efficient conversion of vibrational energy.

[0057] To prevent the metal structure from affecting the moving magnet 16, the optical axis 12 of the electromagnetic multi-stable energy-harvesting oscillator 1 is made of aluminum, the lead screw 18 is made of aluminum, the bolts and nuts are all made of aluminum, and the rest of the parts are made of plastic.

[0058] To prevent the main frame 21 from deforming during vibration, a fixing rod 210 is installed between the two side plates 219 of the main frame 21. The fixing rod 210 is a long threaded rod, with both ends inserted into the corresponding mounting holes on the side plates 219, and fixed by nuts screwed onto the side plates 219. The fixing rod 210 effectively prevents the main frame 21 from deforming due to excessive force of the horizontal spring 25, which would affect the performance of the multistable electromagnetic energy harvesting vibration absorber.

[0059] The nonlinear vibration suppression device 2 has multiple mounting holes on its base plate 218 and back plate 220 for fixing the main frame 21 with fasteners, thus installing the entire multistable electromagnetic energy harvesting vibration absorber in the required installation environment to achieve vibration suppression and energy harvesting. When the main frame 21 vibrates, it drives the moving frame 211 to vibrate, causing the optical axis 12 to vibrate up and down, which in turn causes the moving magnet 16 to move between the two end magnets 13, cutting magnetic field lines. The magnetic flux of the coil 17 changes, generating current to supply power to the electrical equipment.

[0060] The effectiveness of the multistable electromagnetic energy trapping vibration absorber is verified by establishing a mathematical model.

[0061] The stiffness of vertical spring 212 is The stiffness of the horizontal spring 25 is The original lengths of both springs are The length of link 27 is The distance between the fixed points of the two connecting rods 27 on the main frame 21 is The distance between the two ring magnets 15 is The distance between the two end magnets 13 is The inner diameter of the ring magnet 15 is The outer diameter is Thickness is The inner diameters of the end magnet 13 and the moving magnet 16 are both The outer diameter is The thickness of the end magnet 13 is The thickness of the moving magnet 16 is .

[0062] The restoring force of the electromagnetic multistable energy-harvesting oscillator 1 can be obtained using finite element analysis software and expressed in polynomial form:

[0063] (1)

[0064] In the formula, For the vertical displacement of the moving magnet 16, , , This is the nonlinear stiffness coefficient.

[0065] refer to Figure 13 It can be seen that, since the phase diagram contains three potential wells, the electromagnetic multistable energy-harvesting oscillator 1 can achieve tristable large-amplitude motion.

[0066] The restoring force of the nonlinear vibration suppression device 2 is:

[0067] (2)

[0068] In the formula, This represents the vertical displacement of the load-bearing platform 23.

[0069] The dynamic equation of the multi-steady electromagnetic energy trapping vibration absorber is:

[0070] (3)

[0071] In the formula, The total mass of the counterweight 11, the optical axis 12, and the moving magnet 15 is... The mass of the object to be supported on the load-bearing platform 23. Damping for electromagnetic multistable energy-harvesting oscillator 1, This is the damping of the nonlinear vibration suppression device 2. The acceleration of the moving magnet 16, The speed of the moving magnet 16 For the acceleration of the load-bearing platform 23, Let be the velocity of the support platform 23. Using the above formula, the amplitude-frequency response curve of the multi-steady-state electromagnetic energy-harvesting vibration absorber is obtained, see... Figure 14 .

[0072] refer to Figure 14 It can be seen that when the electromagnetic multi-stable energy-harvesting oscillator 1 is installed in the nonlinear vibration suppression device 2, it can effectively suppress the resonance peak, shorten the unstable multi-value range, and enhance the vibration suppression effect.

[0073] refer to Figure 15 It can be seen that by manufacturing an experimental prototype and installing it on a vibration table to conduct a fixed-frequency vibration experiment of 1-15Hz, the nonlinear vibration suppression device 2 exhibits resonance peaks and anti-resonance peaks. Furthermore, at frequencies above 6Hz, the amplitude response of the nonlinear vibration suppression device 2 is less than the amplitude of the external excitation, indicating that the multi-stable electromagnetic energy trapping vibration absorber can effectively suppress low-frequency vibrations.

[0074] The multistable electromagnetic energy trapping vibration absorber described in this application is assembled through the following steps:

[0075] First, attach the end magnet 13 to the inner annular protrusion 113 of the upper end cover 110 and the lower end cover 111, with the magnetic poles of the magnets aligned according to... Figure 5 As shown, the optical axis 12 is passed through the hole with a linear bearing 112 on the upper end cover 110, and a moving magnet 16 is installed at the lower end of the optical axis 12. The magnetic poles of the moving magnet 16 are oriented according to... Figure 5 As shown, a counterweight 11 is installed at the upper optical axis 12 end.

[0076] The second step involves using bolts to clamp two acrylic plates 14 onto both sides of the annular magnet 15, placing them appropriately over the plastic tube 19 covering the coil 17, and securing them with lead screws 18 and nuts. This completes the installation of the two annular magnets 15. The end cap structure assembled in the first step is then fixed to both ends of the plastic tube 19. Adjusting the vertical distance between the two annular magnets allows for different multistable trap widths to accommodate varying external excitation intensities. The electromagnetic multistable energy trap oscillator 1 is now installed.

[0077] The third step is to install the vertical guide rail 22 on the slide groove 215 of the back plate 220 of the main frame 21 using bolts, and install the vertical slider 24 on the vertical guide rail 22. Use screws to fix the vertical slider 24 to the mounting hole on the back of the motion frame 211, so that the motion frame 211 and the vertical slider 24 can move together in the vertical direction. The lower end of the vertical spring 212 is fixed by a clamping plate 213, bolts and nuts and the bottom plate 218 of the main frame 21, and the upper end is fixed by another clamping plate 213, bolts and nuts and the motion frame 211.

[0078] Fourth, a horizontal guide rail 29 is fixedly mounted on the motion frame 211 using screws. Two horizontal sliders 28 are installed on the horizontal guide rail 29, and two horizontal connectors 26 are installed on the horizontal sliders. One end of each of the four horizontal connecting rods 27 is hinged to the horizontal connector 26, and the other end is hinged to the pin 214 inserted into the mounting hole 216 of the main frame 21 (the pin 214 can be inserted into different mounting holes 216 to adjust the distance between the horizontal connecting rods 27 on both sides), allowing the horizontal connecting rods 27 to rotate freely (see details). Figure 7 ).

[0079] Fifth step: Use clamp 213 and bolts and nuts to fix the horizontal spring 25 between the two connecting parts 26, and use screws to fix the load-bearing platform 23 on the moving frame 211. Install the fixing rod 210 on the main frame, adjust the nut on the fixing rod 210 to prevent the deformation of the main frame 21. The nonlinear vibration suppression device 2 is now installed.

[0080] Step 6: Install the lead screw 18 from the electromagnetic multistable energy harvesting oscillator 1 into the hole on the support platform 23 and secure it with a nut. The multistable vibration suppression-energy harvesting integrated device is now installed.

[0081] Step 7: Apply a vertical external excitation to the main frame 21, and the multistable vibration suppression-energy harvesting integrated device begins to work. Since the nonlinear vibration suppression device 2 is a quasi-zero stiffness structure with a low natural frequency, it can achieve low-frequency vibration isolation, protecting the structure on the support platform 23. The electromagnetic multistable energy harvesting oscillator 1 installed on the support platform 23 can suppress the resonance peak of the nonlinear vibration suppression device 2, shorten the unstable range, and further improve vibration suppression performance. The vibration energy transmitted to the electromagnetic multistable energy harvesting oscillator 1 will cause the moving magnet 16 to move vertically, resulting in a change in the magnetic flux in the coil 17. The coil 17 generates current, providing energy to the electrical appliances connected to the coil.

[0082] One application embodiment of the multistable electromagnetic energy harvesting vibration absorber described in this application:

[0083] The multistable electromagnetic energy harvesting vibration absorber described in this application is suitable for energy harvesting and vibration suppression in low-frequency and ultra-low-frequency vibration environments, including but not limited to aerospace, rail transportation, machining, and offshore wind power. Installing this integrated multistable vibration suppression and energy harvesting device can protect equipment and provide energy to its microelectromechanical sensors. For example, installing this multistable electromagnetic energy harvesting vibration absorber under the aircraft cockpit and fixing the seat to the support platform 23 (holes can be drilled or a connection structure designed on the support platform according to the specific situation of the seat) can reduce the impact of aircraft structural vibration on the pilot. Furthermore, the vibration energy captured by the electromagnetic multistable energy harvesting oscillator 1 can provide energy for low-power sensors on the aircraft.

[0084] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A multi-stable electromagnetic energy-harvesting vibration absorber, characterized by, include: A nonlinear vibration suppression device and an electromagnetic multistable energy-harvesting oscillator installed on the nonlinear vibration suppression device. The nonlinear vibration suppression device is used to suppress vibration and transfer vibration energy to the electromagnetic multistable energy-harvesting oscillator. The electromagnetic multistable energy-harvesting oscillator is used to convert vibration energy into electrical energy to supply electrical equipment. The nonlinear vibration suppression device is a quasi-zero stiffness structure, which includes a main frame, a moving frame installed inside the main frame, and the moving frame and the main frame are elastically connected by a vertical spring assembly and a horizontal spring assembly. The moving frame is also vertically slidably connected to the main frame by a vertical slide rail assembly. The electromagnetic multistable energy-harvesting oscillator includes two end caps arranged vertically opposite each other, referred to as the upper end cap and the lower end cap. A plastic tube is vertically installed between the two end caps, and an optical axis is coaxially installed inside the plastic tube. The optical axis passes through the upper end cap, and a counterweight is installed at its end outside the upper end cap, while a moving magnet is installed at its end inside the plastic tube. The optical axis and the upper end cap are slidably connected. End magnets are installed on the opposite surfaces of the two end caps, and the end magnets are located inside the plastic tube. A coil is wound around the outside of the plastic tube, and the coil is connected to an external power supply device. Two annular magnets are coaxially fitted around the plastic tube, and the two annular magnets are mounted between two end caps via a screw mounting assembly; the lower end cap of the plastic tube is mounted on the moving frame; when the moving frame vibrates, the moving magnets move between the two end magnets, the magnetic flux of the coil changes, and a current is generated to supply power to the electrical equipment.

2. The multi-stable electromagnetic energy-harvesting vibration absorber of claim 1, wherein, The horizontal spring assembly includes a horizontal guide rail, which is installed inside the frame of the motion frame and runs horizontally through the motion frame. Two horizontal sliders are slidably installed on the horizontal guide rail, and a connector is installed on each horizontal slider. The two connectors face each other and are elastically connected by a horizontal spring. The end of the connector facing away from the horizontal spring is hinged to the main frame through a connecting rod. One end of the connecting rod is hinged to the connector, and the other end is hinged to the main frame.

3. The multistable electromagnetic energy trapping vibration absorber according to claim 2, characterized in that, The motion frame is a hollow frame structure, which does not restrict the displacement of the two connecting parts along the horizontal guide rail. A load-bearing platform is fixedly installed on the upper end of the motion frame, and an electromagnetic multi-stable energy-harvesting oscillator is installed on the load-bearing platform.

4. The multistable electromagnetic energy trapping vibration absorber according to claim 2, characterized in that, The main frame is an irregular frame structure, which includes a base plate, two side plates and a back plate. The two side plates are symmetrically installed at both ends of the back plate, and the back plate is installed on the base plate. The side plates are provided with mounting ears on their inner sides. Multiple mounting holes are provided in a horizontal line on the mounting ears. Pins are inserted into the mounting holes and are used for hinged connection between the connecting rods and the main frame. The distance between the connecting rods on both sides can be adjusted by adjusting the hole positions when the connecting rods and the main frame are hinged.

5. The multistable electromagnetic energy harvesting vibration absorber according to claim 4, characterized in that, The vertical slide rail assembly includes a vertical guide rail, which is spatially perpendicular to the horizontal guide rail. It is installed on the inner side of the back plate of the main frame. A vertical slider is slidably installed on the vertical guide rail, and the vertical slider is fixedly connected to the side wall of the moving frame. When the moving frame vibrates, it moves up and down along the vertical guide rail with the vertical slider.

6. The multistable electromagnetic energy trapping vibration absorber according to claim 1, characterized in that, The vertical spring assembly includes a vertical spring, the lower end of which is fixedly connected to the main frame via a set of fastening connectors, and the upper end of which is fixedly connected to the lower end face of the moving frame via another set of fastening connectors.

7. The multistable electromagnetic energy trapping vibration absorber according to claim 1, characterized in that, The end cap is made of plastic. Two coaxial annular protrusions are provided in the middle of one side of the end cap. The inner annular protrusion is higher than the outer annular protrusion. The center of the inner annular protrusion has a through hole along the axial direction. The annular protrusions of the two end caps are opposite each other. The two ends of the plastic tube are respectively embedded in the gap between the corresponding two annular protrusions and glued and fixed. The outer diameter of the inner annular protrusion is in contact with the inner diameter of the plastic tube. The end magnet is fixedly installed on the end face of the inner annular protrusion.

8. The multistable electromagnetic energy trapping vibration absorber according to claim 1, characterized in that, A linear bearing is installed in the through hole of the upper end cover, and the optical axis is inserted into the linear bearing. The linear bearing is used for the sliding connection between the optical axis and the upper end cover.

9. The multistable electromagnetic energy harvesting vibration absorber according to claim 1, characterized in that, The lead screw mounting assembly includes two lead screws and multiple acrylic plates. The two lead screws are fixedly connected between two end caps and are parallel and equidistant from the plastic tube. Each annular magnet is clamped and fixed by two upper and lower acrylic plates. The two ends of the acrylic plates are respectively fitted onto the two lead screws and their installation positions are locked by fasteners. The acrylic plates have a through hole in the center for fitting onto the outside of the plastic tube. The installation positions of the two annular magnets in the axial direction of the lead screws are adjustable.

10. The multistable electromagnetic energy trapping vibration absorber according to claim 1, characterized in that, The two end magnets have the same magnetic pole direction, with the north pole pointing upwards and the south pole pointing downwards; the magnetic pole direction of the moving magnet and the two ring magnets are the same, and are opposite to the magnetic pole direction of the end magnets.

Images