Triboelectric magnetic repulsion structure vibration sensing device and control method thereof

Abstract

This invention relates to the field of vibration sensing and equipment condition monitoring technology, and particularly to a triboelectric magnetic repulsion structure vibration sensing device and its control method. The device includes a top end cover, a sensing unit, and a housing. The sensing unit includes an oscillator, a flexible support assembly, a magnetic repulsion assembly, and two opposing fixed and movable friction assemblies. The oscillator is connected to the housing via the flexible support assembly. The magnetic repulsion assembly provides a force to the oscillator towards the top end cover, causing the two friction assemblies to contact in a static state. When the object being measured vibrates, the oscillator moves relative to the housing, causing the two friction assemblies to contact and separate, outputting a triboelectric signal. After signal conditioning and feature extraction, the operating status is determined, and an alarm or control command is output. This invention does not require an external excitation power supply to generate the sensing signal and can be used for equipment vibration monitoring and operation control.

Description

Technical Field

[0001] This invention relates to the field of vibration sensing and equipment condition monitoring technology, and in particular to a triboelectric magnetic repulsion structure vibration sensing device and its control method. Background Technology

[0002] The equipment housing, transmission components, and actuators generate vibrations during operation. Parameters such as vibration frequency, vibration amplitude, and acceleration can be used to reflect the operating status of the equipment. By collecting and analyzing vibration signals, a basis can be provided for early warning of equipment anomalies and adjustment of operating parameters.

[0003] Vibration monitoring devices typically require converting the mechanical vibration of the object under test into electrical signals, which are then analyzed by signal processing equipment. For sensing elements that require external power supply, the power supply and signal lines increase the workload of installation and maintenance, and their use is limited in situations where installation space is limited or wiring conditions are poor.

[0004] Triboelectric vibration sensors utilize triboelectric charging and electrostatic induction to generate electrical signals, reducing the sensor's dependence on an external excitation power source. In devices employing a contact-separation method, the initial positional relationship between the two friction surfaces affects the vibration response. When the two friction surfaces initially have a gap, the relative displacement caused by the vibration needs to reach that gap for the two friction surfaces to make contact. For vibrations with small relative displacements, insufficient or no contact may occur, affecting signal output.

[0005] Furthermore, the support method and motion constraints of the oscillator also affect the contact separation process. The stiffness, damping, and installation status of the support structure will change the dynamic response of the oscillator; oscillation of the oscillator or local contact of the friction surface may also cause changes in the effective contact area in different vibration cycles, affecting the consistency of the output signal.

[0006] Therefore, this application designs a vibration sensing device that can operate in the initial contact state and takes into account axial motion, circumferential constraint and friction surface contact adaptability, and establishes a vibration monitoring and control method adapted to its electrical signal output. Summary of the Invention

[0007] This invention provides a triboelectric magnetic repulsion structure vibration sensing device and its control method. By cooperating with a flexible support and a magnetic repulsion support, the two friction components are brought into contact in a static state after assembly. The relative motion of the oscillator caused by the vibration of the object being measured generates a triboelectric signal, which improves the limitation of the initial gap on the response to small displacement vibrations and is used for equipment operation status monitoring and control.

[0008] A triboelectric magnetic repulsion vibration sensing device includes a top end cover, a sensing unit, and a housing. The top end cover is fixedly connected to the housing and forms an installation space. The sensing unit, located within the installation space, includes an oscillator, a fixed friction assembly, a movable friction assembly, a flexible support assembly, and a magnetic repulsion assembly. The fixed friction assembly is located inside the top end cover, and the movable friction assembly is located on the side of the oscillator facing the fixed friction assembly. The oscillator is connected to the housing via the flexible support assembly. The magnetic repulsion assembly is located between the bottom of the oscillator and the housing, providing a magnetic repulsion force towards the top end cover to the oscillator. This allows the fixed friction assembly and the movable friction assembly to contact each other in a static state after assembly, and to separate as the oscillator moves axially relative to the housing.

[0009] Furthermore, in order to better realize the present invention, the magnetic repulsion assembly includes a circular magnet and an annular magnet. The circular magnet is disposed on the oscillator, and the annular magnet is fixed inside the housing and located below the circular magnet. The circular magnet and the annular magnet are coaxial along the axial direction and spaced apart, and the magnetic poles on opposite sides are the same.

[0010] Furthermore, in order to better realize the present invention, the oscillator includes a weight block and a circular magnet, the weight block being fixed to the upper end of the circular magnet; the movable friction component is disposed on the side of the weight block facing the fixed friction component, and a sponge adhesive is disposed between the weight block and the movable friction component.

[0011] Furthermore, to better realize the present invention, the flexible support assembly includes an upper film plate, a PDMS film, a lower film plate, and a key; the periphery of the PDMS film is sandwiched between the upper film plate and the lower film plate, and the central region is connected to the oscillator; the upper film plate, the PDMS film, and the lower film plate are respectively provided with corresponding film fixing holes in their circumferential directions, and the key passes through the film fixing holes; the upper film plate and the lower film plate are fixedly connected to the outer shell.

[0012] Furthermore, to better realize the present invention, the fixed friction assembly includes a first electrode layer and a nylon layer, with the first electrode layer disposed between the top end cap and the nylon layer; the movable friction assembly includes a second electrode layer and a PTFE layer, with the second electrode layer disposed between the sponge adhesive and the PTFE layer; both the first electrode layer and the second electrode layer are made of copper foil, the surfaces of the nylon layer and the PTFE layer are disposed opposite to each other, and the first electrode layer and the second electrode layer are respectively connected to signal lead wires.

[0013] Furthermore, in order to better realize the present invention, the top end cover includes an end shell and an acrylic plate. The end shell is provided with a circular groove and a wire hole. The acrylic plate is fixed in the circular groove, and the fixed friction assembly is disposed on the side of the acrylic plate facing the installation space. The signal lead wires of the fixed friction assembly and the movable friction assembly are led out through the wire hole.

[0014] Furthermore, in order to better realize the present invention, the outer shell includes a magnetic ring cover, a housing, and a base. The housing is disposed between the top end cover and the base. The base is provided with a magnetic ring holder, the annular magnet is installed in the magnetic ring holder, and the magnetic ring cover is pressed on top of the annular magnet and fixedly connected to the base.

[0015] Furthermore, in order to better realize the present invention, the top end cap, the peripheral fixing part of the sensing unit and the housing are connected by bolts; the top end cap, housing and base are made of non-magnetic material, and the base is used to rigidly connect with the object being measured.

[0016] A control method for a triboelectric magnetic repulsion structure vibration sensing device, applied to the aforementioned triboelectric magnetic repulsion structure vibration sensing device, includes the following steps: The outer casing is fixedly connected to the object being tested, so that the fixed friction component and the movable friction component remain in contact in a static state; When the object under test vibrates, the outer shell and the top end cap move with the object under test. Under the action of inertia, the oscillator generates axial movement relative to the outer shell, causing the fixed friction component and the movable friction component to make contact-separation movement and output a triboelectric signal. Signal conditioning and feature extraction of triboelectric signals are performed to obtain vibration characteristic parameters of the object under test; The operating status of the object under test is determined based on the vibration characteristic parameters, and alarm signals and control commands corresponding to the operating status are output to the equipment control system.

[0017] Furthermore, in order to better realize the present invention, the vibration characteristic parameters include at least one of vibration frequency, vibration amplitude and acceleration; the vibration characteristic parameters are compared with the corresponding preset safety thresholds, and when at least one vibration characteristic parameter exceeds the corresponding preset safety threshold, the tested object is determined to be in an abnormal vibration state, and at least one of alarm signal, shutdown control signal and operating parameter adjustment signal is output to the equipment control system.

[0018] The beneficial effects of this invention are: Compared to contact-separation structures that employ an initial separation arrangement, this invention allows the fixed friction component and the movable friction component to contact each other in a static state, eliminating the need to first cross a preset initial gap to establish frictional contact. When the relative action generated by vibration is sufficient to relieve the initial contact pressure, the two friction surfaces can separate and generate an electrical signal.

[0019] The magnetic repulsion assembly provides support towards the top end cap, while the flexible support assembly allows axial movement of the oscillator while constraining its lateral displacement and yaw. Together, they reduce reliance on mechanical spring supports and provide support conditions for the oscillator's contact-separation motion.

[0020] The sponge adhesive is placed between the load-bearing block and the moving friction component. It can adapt to the assembly error of the friction surface through local compression, mitigate the impact when contacting again, and help improve the consistency of the effective contact area.

[0021] The sensing unit generates a triboelectric signal using contact separation motion, and the signal generation process does not require an external excitation power source. After processing by external equipment, the output signal can be used for vibration feature extraction, abnormal state detection, alarm functions, or equipment operation control. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the vibration sensing device of the present invention; Figure 2 This is an exploded structural diagram of the vibration sensing device of the present invention; Figure 3 This is a schematic cross-sectional view of the vibration sensing device of the present invention. Figure 4 This is one of the structural schematic diagrams of some of the sensing units of the present invention; Figure 5 This is a second schematic diagram of the structure of some sensing units of the present invention; Figure 6 This is a schematic diagram of the top end cap of the present invention; Figure 7 This is a schematic diagram of the structure of the base of the present invention; Figure 8 This is a flowchart illustrating the operation of the vibration sensing device of the present invention.

[0023] In the picture, 1. Top end cap, 2. Sensing unit, 3. Housing, 4. Vibrator, 5. Fixed friction assembly, 6. Movable friction assembly, 11. End shell, 12. Acrylic sheet, 13. Copper foil, 14. Nylon layer, 22. Sponge adhesive, 23. Weight block, 24. Upper platen of film, 25. PDMS film, 26. Lower platen of film, 27. Circular magnet, 28. Ring magnet, 29. Pin, 31. Ring magnet cover, 32. Housing, 33. Base, 111. Wire hole, 112. Circular groove, 241. Film fixing hole, 331. Ring magnet holder. Detailed Implementation

[0024] 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 a part of the embodiments of the present invention, and not all of them. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0025] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0026] Figures 1-8 As a specific embodiment of the present invention, such as Figures 1 to 5 As shown, the vibration sensing device includes a top end cover 1, a sensing unit 2, and a housing 3. The top end cover 1 is mounted on the upper end of the housing 3, and the two together form an installation space for accommodating the sensing unit 2.

[0027] The sensing unit 2 includes an oscillator 4, a fixed friction assembly 5, a movable friction assembly 6, a flexible support assembly, and a magnetic repulsion assembly. The fixed friction assembly 5 is mounted on the side of the top end cover 1 facing the installation space, and the movable friction assembly 6 is mounted on the upper side of the oscillator 4, with their friction surfaces arranged opposite each other along the axial direction.

[0028] The periphery of the flexible support assembly is fixed to the housing 3, and its central portion is connected to the oscillator 4, positioning the oscillator 4 in the center of the installation space. A magnetic repulsion assembly is disposed between the oscillator 4 and the bottom of the housing 3, providing a force to the oscillator 4 towards the top end cap 1. The flexible support assembly and the magnetic repulsion assembly together influence the movement of the oscillator 4 relative to the housing 3.

[0029] The top end cap 1, the peripheral fixing part of the flexible support assembly, and the outer shell 3 are connected by circumferentially arranged bolts. The bolt connection fixes the outer support part of the sensing unit 2, without directly locking the oscillator 4 to the outer shell 3, so as to retain the axial movement capability of the oscillator 4.

[0030] The bottom of the outer casing 3 is fixedly connected to the object being measured. During installation, the axis of the device should be aligned with the main vibration direction to be monitored, and the mounting surface should be in contact with the object, with the connecting parts tightened to reduce the impact of loose installation on the measurement results. This embodiment is mainly used to obtain vibration information of the object being measured along the axis of the device, and does not directly use the output of a single device as the independent vibration measurement results in three directions.

[0031] like Figure 2 , Figure 3 and Figure 6 As shown, the top end cap 1 includes an end shell 11 and an acrylic plate 12. A circular groove 112 is provided inside the end shell 11, and the acrylic plate 12 is embedded in the circular groove 112 and fixed.

[0032] The acrylic plate 12 provides a support surface for the fixed friction assembly 5. The fixed friction assembly 5 includes a first electrode layer and a nylon layer 14, wherein the first electrode layer is composed of copper foil 13. From the top end cap 1 toward the oscillator 4, the acrylic plate 12, the first electrode layer, and the nylon layer 14 are arranged in sequence, and the surface of the nylon layer 14 facing away from the first electrode layer is the fixed friction surface.

[0033] During bonding, the first electrode layer and the acrylic plate 12, and the nylon layer 14 and the first electrode layer should be kept flat to avoid obvious wrinkles or localized lifting. The wire connection position of the first electrode layer should be set in an area that does not affect effective frictional contact, so that the wire connection does not protrude from the relative contact area of ​​the two friction surfaces.

[0034] The side wall of the end shell 11 is provided with a wire hole 111. The first electrode layer and the second electrode layer are respectively connected to signal lead wires, and the two wires are led to external signal processing equipment through the wire hole 111. The first electrode layer and the second electrode layer constitute different electrical signal terminals and are not directly short-circuited inside the device.

[0035] like Figures 2 to 5 As shown, the oscillator 4 includes a weight block 23 and a circular magnet 27. The upper end of the weight block 23 and the circular magnet 27 are fixedly connected, and the two move together during operation.

[0036] The weight block 23 provides inertial mass, which, together with the mass of the circular magnet 27 and the follower components, constitutes the effective kinematic mass of the oscillator 4. The mass selection needs to be coordinated with the flexible support components, the magnetic repulsion components, and the target vibration frequency band; increasing the mass of the weight block 23 is not the only way to improve the response across all frequency bands.

[0037] The movable friction assembly 6 is positioned above the load-bearing block 23 and includes a second electrode layer and a PTFE layer. PTFE is polytetrafluoroethylene. The second electrode layer is composed of copper foil 13, which is independent of the first electrode layer.

[0038] From the weight block 23 toward the top end cap 1, the layers are, in sequence, sponge adhesive 22, second electrode layer, and PTFE layer. The surface of the PTFE layer facing away from the second electrode layer is the movable friction surface, which is opposite to the fixed friction surface of the nylon layer 14.

[0039] The sponge 22 connects the load-bearing block 23 to the movable friction assembly 6 and provides compressible cushioning support. When the two friction surfaces come into contact, the sponge 22 can produce local deformation to accommodate small-range non-parallelism or flatness differences between the friction surfaces.

[0040] The compression of the sponge adhesive 22 should match the initial contact pressure after assembly. Insufficient compression may result in only partial contact between the two friction surfaces; excessive compression may increase the force required to release the contact during vibration. Therefore, when determining the thickness and compression degree of the sponge adhesive 22, both the initial contact condition and the separation condition under the target vibration conditions should be checked simultaneously.

[0041] The wires connecting the second electrode layer move locally with the oscillator 4. The wires are kept within the installation space to allow for sufficient movement, and avoid the gap between the circular magnet 27 and the ring magnet 28 and the contact area of ​​the two friction surfaces, so as to prevent the wires from being pinched or exerting significant tension on the oscillator 4.

[0042] like Figures 2 to 6 As shown, the flexible support assembly includes an upper film platen 24, a PDMS film 25, a lower film platen 26, and pins 29. PDMS is polydimethylsiloxane.

[0043] The PDMS film 25 is sandwiched between the upper film plate 24 and the lower film plate 26. Each of the three plates has a corresponding film fixing hole 241 in its circumferential direction. The pin 29 passes through the corresponding film fixing hole 241 to limit the interlayer positional displacement.

[0044] The upper film pressure plate 24 and the lower film pressure plate 26 are fixedly connected to the outer shell 3, forming a clamping effect on the periphery of the PDMS film 25. The pin 29 engages with the film fixing hole 241 to achieve positioning. The clamping effect between the pressure plates is used to keep the periphery of the film fixed, avoiding the need for the wall of the film fixing hole 241 to bear all the repeated loads.

[0045] The oscillator 4 is connected to the central region of the PDMS film 25. The portion of the PDMS film 25 between the central connection region and the peripheral clamping region is a deformable region. When the oscillator 4 moves axially, this region deforms accordingly; when the oscillator 4 deviates from the central position or tilts, the deformation of the film also constrains it.

[0046] A set of circular magnets 27 are held at the center of the PDMS film 25 by magnetic clamping. In this method, the magnetic attraction occurs between mutually attracting magnetic components; the PDMS film 25 is in the clamping position and does not rely on the PDMS material itself for magnetic adsorption. During assembly, the center clamping area should correspond to the center of the two pressure plates, and damage to the film should be avoided at the clamping edges.

[0047] The central clamping relationship and the magnetic repulsion relationship between the circular magnet 27 and the ring magnet 28 are respectively set: the former is used to maintain the connection between the center of the thin film and the oscillator 4, and the latter is used to provide axial magnetic repulsion support. The surface of the circular magnet 27 opposite to the ring magnet 28 should maintain the same pole as the opposite surface of the ring magnet 28.

[0048] The thickness, effective deformation area, and assembly tension of the PDMS film 25 affect the support stiffness. During assembly, the film should be subjected to relatively uniform circumferential force to avoid excessive tension on one side and significant slack on the other. The deformable area of ​​the film should not form continuous frictional contact with the housing 32 to avoid further restricting the movement of the oscillator 4.

[0049] In this embodiment, the suspension support refers to the oscillator 4 being supported by a flexible film and magnetic repulsion, rather than the oscillator 4 being completely detached from the mechanical connection and freely magnetically levitated.

[0050] like Figure 2 , Figure 3 , Figure 5 and Figure 7 As shown, the outer casing 3 includes a magnetic pressure cap 31, a housing 32, and a base 33. The housing 32 is located between the top end cap 1 and the base 33, and the base 33 supports the magnetic repulsion assembly and is used to connect the object under test.

[0051] The base 33 is provided with a magnetic ring holder 331, and the annular magnet 28 is installed in the magnetic ring holder 331. The magnetic ring holder 331 provides positional constraint for the annular magnet 28. The magnetic ring cover 31 is pressed on top of the annular magnet 28 and is fixedly connected to the base 33 by bolts, thereby restricting the movement of the annular magnet 28 during operation.

[0052] The circular magnet 27 is positioned above the annular magnet 28, and the two are coaxially arranged along the axis of the device, with the same magnetic poles on opposite sides. A gap is maintained between the two magnets so that the circular magnet 27 does not collide with the annular magnet 28 or the annular magnet cover 31 within a predetermined working stroke when it moves with the oscillator 4.

[0053] In the vertical orientation shown in the diagram, the ring magnet 28 provides an upward magnetic repulsion force to the circular magnet 27. The oscillator 4 is simultaneously subjected to gravity, the elastic force of the PDMS film 25, and the contact reaction force when the two friction components come into contact.

[0054] The initial contact state after assembly is determined by the aforementioned forces and cannot be judged solely based on the fact that the magnetic repulsion force is greater than the gravity of the oscillator 4. The initial deformation of the PDMS film 25 should also be considered to ensure that the movable friction component 6 can contact the fixed friction component 5 and form an initial contact pressure that meets the contact requirements.

[0055] When determining the structural dimensions, the initial contact pressure can be determined by selecting the specifications of the circular magnet 27 and the ring magnet 28, the initial spacing, the mass of the load block 23, and the assembly state of the PDMS film 25. These parameters are determined before assembly, and no additional active adjustment mechanism is required beyond the attached drawings.

[0056] The initial contact pressure should not be too high. When the object under test vibrates, the two friction surfaces will only effectively separate when the relative dynamic action of the oscillator 4 is sufficient to reduce the contact pressure to zero and form a separation displacement. Therefore, initial contact does not mean that the device can produce a recognizable output for arbitrarily small vibrations. Its lower limit of response needs to be determined under specific assembly conditions and measurement circuit conditions.

[0057] The top end cap 1, housing 32, and base 33 are made of non-magnetic material to reduce the influence of the outer shell structure on the internal magnetic field distribution. Non-magnetic material is not the same as magnetic shielding material. When using it, attention should still be paid to the possible influence of strong external magnetic fields and nearby ferromagnetic objects on the magnetic repulsion support state.

[0058] This embodiment can be assembled in the following order.

[0059] First, place the ring magnet 28 into the ring magnet holder 331 of the base 33, check the installation direction and the orientation of the magnetic poles, then install and tighten the ring magnet cover 31. After tightening, check whether the ring magnet 28 is loose, to avoid using the magnet body as a part that requires significant compression deformation.

[0060] Next, place the PDMS film 25 between the upper film platen 24 and the lower film platen 26, align the film fixing holes 241, insert the key pins 29, and evenly clamp the periphery of the film. Keep the oscillator 4 in the center area of ​​the film and check the relative position between the oscillator 4 and the pressure plate.

[0061] Subsequently, the weight block 23 is fixedly connected to the circular magnet 27. A sponge adhesive 22, a second electrode layer, and a PTFE layer are sequentially applied to the weight block 23 to form a movable friction assembly 6. The acrylic plate 12 is fixed in the circular groove 112 of the end shell 11, and then a first electrode layer and a nylon layer 14 are applied to form a fixed friction assembly 5.

[0062] After completing the wire connection between the two electrodes, install the flexible support assembly into the outer casing 3, making the circular magnet 27 and the ring magnet 28 coaxial and with the same relative magnetic poles. Organize the internal wires to prevent them from entering the movement interval and friction contact area.

[0063] Finally, install the top end cap 1 and gradually tighten the connecting bolts circumferentially. During the tightening process, check the alignment of the two friction surfaces, the compression of the sponge adhesive 22, and the deformation of the PDMS film 25 to avoid significant tilting caused by tightening on one side.

[0064] After assembly, first check whether the two friction surfaces are in contact when stationary. Then apply a small axial reciprocating excitation to check whether the oscillator 4 can separate and re-engage the two friction surfaces, and whether there is any internal collision, jamming, or wire pulling. After passing the inspection, proceed with measurement and calibration.

[0065] When stationary, the movable friction component 6 contacts the fixed friction component 5 under the combined action of the magnetic repulsion component and the flexible support component. The nylon layer 14 and the PTFE layer form a triboelectric interface through contact. When the object under test vibrates, the base 33, the housing 32, the top end cap 1, and the fixed friction component 5 move with the object under test. The oscillator 4 is subjected to inertia, magnetic repulsion, and thin film elasticity, and its movement is not completely synchronized with that of the outer shell 3, thus forming axial relative motion.

[0066] During the vibration phase, which reduces the initial contact pressure, if the dynamic action reaches the separation condition, the movable friction component 6 moves away from the fixed friction component 5, increasing the distance between the two friction surfaces. As the relative position changes, the potential relationship between the first electrode layer and the second electrode layer changes, generating an electrical signal after being connected to the measurement circuit.

[0067] In the subsequent motion phase, the oscillator 4 returns relative to the top end cap 1, the distance between the two friction surfaces decreases, and they come into contact again. The sponge adhesive 22 undergoes local compression upon re-contact, mitigating the contact impact. As the tested object continues to vibrate, the above process repeats, generating a time-varying electrical signal related to the contact-separation motion.

[0068] The waveform and amplitude of the triboelectric signal are also affected by factors such as contact area, surface condition, input impedance of the measuring circuit, ambient humidity, and excitation frequency. Therefore, this embodiment establishes the correspondence between the output signal and the measured vibration parameters through calibration, and does not directly regard the uncalibrated voltage amplitude as mechanical displacement or acceleration.

[0069] This device does not require an external excitation power supply when generating sensing signals. The external signal conditioning circuit, data acquisition equipment, host computer, and equipment control system can each use their own power supply methods. This embodiment does not assume that the triboelectric output can directly supply all of the above-mentioned devices.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention, as long as they do not depart from the spirit and scope of the technical solutions of the present invention, should be covered within the scope of the claims of the present invention.

Claims

1. A triboelectric magnetic repulsion structure vibration sensing device, comprising a top end cap (1), a sensing unit (2), and a housing (3), characterized in that: The top end cap (1) is fixedly connected to the outer shell (3) and forms an installation space. The sensing unit (2) is set in the installation space and includes an oscillator (4), a fixed friction assembly (5), a movable friction assembly (6), a flexible support assembly, and a magnetic repulsion assembly. The fixed friction assembly (5) is set inside the top end cap (1), and the movable friction assembly (6) is set on the side of the oscillator (4) facing the fixed friction assembly (5). The oscillator (4) is connected to the outer shell (3) through the flexible support assembly. The magnetic repulsion assembly is set between the bottom of the oscillator (4) and the outer shell (3) and provides magnetic repulsion force to the oscillator (4) towards the top end cap (1), so that the fixed friction assembly (5) and the movable friction assembly (6) are in contact in the static state after assembly, and can undergo contact separation movement with the axial movement of the oscillator (4) relative to the outer shell (3).

2. The triboelectric magnetic repulsion structure vibration sensing device according to claim 1, characterized in that: The magnetic repulsion assembly includes a circular magnet (27) and an annular magnet (28). The circular magnet (27) is disposed on the oscillator (4), and the annular magnet (28) is fixed inside the housing (3) and located below the circular magnet (27). The circular magnet (27) and the annular magnet (28) are coaxially spaced along the axial direction, and the magnetic poles on opposite sides are the same.

3. The triboelectric magnetic repulsion structure vibration sensing device according to claim 2, characterized in that: The oscillator (4) includes a weight block (23) and a circular magnet (27). The weight block (23) is fixed to the upper end of the circular magnet (27). The movable friction component (6) is located on the side of the weight block (23) facing the fixed friction component (5). A sponge adhesive (22) is provided between the weight block (23) and the movable friction component (6).

4. The triboelectric magnetic repulsion structure vibration sensing device according to claim 1, characterized in that: The flexible support assembly includes an upper film plate (24), a PDMS film (25), a lower film plate (26), and a key (29). The periphery of the PDMS film (25) is sandwiched between the upper film plate (24) and the lower film plate (26), and the central area is connected to the oscillator (4). The upper film plate (24), the PDMS film (25), and the lower film plate (26) are respectively provided with corresponding film fixing holes (241) in the circumferential direction, and the key (29) passes through the film fixing holes (241). The upper film plate (24) and the lower film plate (26) are fixedly connected to the outer shell (3).

5. The triboelectric magnetic repulsion structure vibration sensing device according to claim 3, characterized in that: The fixed friction assembly (5) includes a first electrode layer and a nylon layer (14), with the first electrode layer disposed between the top end cap (1) and the nylon layer (14); the movable friction assembly (6) includes a second electrode layer and a PTFE layer, with the second electrode layer disposed between the sponge adhesive (22) and the PTFE layer; both the first electrode layer and the second electrode layer are made of copper foil (13), and the surfaces of the nylon layer (14) and the PTFE layer are disposed opposite to each other, with signal lead wires connected to the first electrode layer and the second electrode layer respectively.

6. The triboelectric magnetic repulsion structure vibration sensing device according to claim 1, characterized in that: The top end cap (1) includes an end shell (11) and an acrylic plate (12). The end shell (11) is provided with a circular groove (112) and a wire hole (111). The acrylic plate (12) is fixed in the circular groove (112). The fixed friction assembly (5) is provided on the side of the acrylic plate (12) facing the installation space. The signal lead wires of the fixed friction assembly (5) and the movable friction assembly (6) are led out through the wire hole (111).

7. The triboelectric magnetic repulsion structure vibration sensing device according to claim 1, characterized in that: The outer casing (3) includes a magnetic ring cover (31), a housing (32) and a base (33). The housing (32) is located between the top end cover (1) and the base (33). The base (33) is provided with a magnetic ring holder (331). A ring magnet (28) is installed in the magnetic ring holder (331). The magnetic ring cover (31) is pressed on top of the ring magnet (28) and fixedly connected to the base (33).

8. The triboelectric magnetic repulsion structure vibration sensing device according to claim 1, characterized in that: The top end cap (1), the peripheral fixed part of the sensing unit (2) and the outer shell (3) are connected by bolts; the top end cap (1), the outer shell (32) and the base (33) are made of non-magnetic material, and the base (33) is used to rigidly connect with the object being measured.

9. A control method for a triboelectric magnetic repulsion structure vibration sensing device, applied to the triboelectric magnetic repulsion structure vibration sensing device according to any one of claims 1 to 8, characterized in that, Includes the following steps: The outer shell (3) is fixedly connected to the object being tested, so that the fixed friction assembly (5) and the movable friction assembly (6) remain in contact in a static state; When the object under test vibrates, the outer shell (3) and the top end cap (1) move with the object under test. The oscillator (4) moves axially relative to the outer shell (3) under inertia, causing the fixed friction assembly (5) and the movable friction assembly (6) to make contact separation and output a frictional electrical signal. Signal conditioning and feature extraction of triboelectric signals are performed to obtain vibration characteristic parameters of the object under test; The operating status of the object under test is determined based on the vibration characteristic parameters, and alarm signals and control commands corresponding to the operating status are output to the equipment control system.

10. The control method of the triboelectric magnetic repulsion structure vibration sensing device according to claim 9, characterized in that: The vibration characteristic parameters include at least one of vibration frequency, vibration amplitude, and acceleration; the vibration characteristic parameters are compared with the corresponding preset safety thresholds, and when at least one vibration characteristic parameter exceeds the corresponding preset safety threshold, the tested object is determined to be in an abnormal vibration state, and at least one of an alarm signal, a shutdown control signal, and an operating parameter adjustment signal is output to the equipment control system.

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