A magnetic control negative stiffness adjusting method and an actuator

Abstract

The application discloses a kind of magnetic control negative stiffness adjusting methods, comprising the following steps: two magneto-rheological elastomer units are respectively arranged, and rigid member is connected between two magneto-rheological elastomer units;Pre-compression force perpendicular to two magneto-rheological elastomer units is applied to rigid member, so that deformation is generated in the direction of two magneto-rheological elastomer unit connecting line respectively and pre-shear force is generated, while negative stiffness force is generated in the direction perpendicular to two magneto-rheological elastomer unit connecting line;The same adjustable magnetic field of size is arranged on two magneto-rheological elastomer units respectively, and the size of magnetic field is controlled, so that the negative stiffness force value generated by two magneto-rheological elastomers can be controlled;The application can solve the current magneto-rheological elastomer vibration isolation mechanism stiffness value is higher and can only be positively regulated, it is difficult to carry out stiffness negative regulation, and then it is difficult to simultaneously exist for the equipment of direct disturbance and external disturbance, realize the technical problem of efficient vibration isolation and stability.

Description

Technical Field

[0001] This invention relates to the field of vibration reduction and isolation technology, specifically to a magnetically controlled negative stiffness adjustment method and actuator. Background Technology

[0002] With the trend of intelligent and precise equipment development, the adverse effects of vibration on the dynamic performance of equipment are becoming more prominent, and the demand for structural vibration suppression is increasing.

[0003] Vibration disturbance excitation can be divided into external disturbances applied to the foundation and direct disturbances applied directly to the equipment. For example, a precision lithography platform is subject to rotational excitation from the lithography operation equipment, air turbulence, and random pulsations from the ground; similarly, a building structure is subject to direct wind-induced vibrations and may also face seismic fluctuations from the foundation.

[0004] For external disturbances to the foundation, vibration isolation technology is generally used to reduce the system stiffness and isolate the transmission of disturbance energy; for direct disturbances, the system stability is generally improved by increasing the system stiffness.

[0005] However, when dealing with equipment subjected to both direct and external disturbances, there is a conflict in choosing the structural stiffness. Therefore, a vibration isolation and stabilization mechanism with adaptively adjustable system stiffness is needed.

[0006] Existing technologies include structural stiffness control techniques based on magnetorheological elastomer materials. Although using special materials can achieve high-stability vibration isolation for equipment subjected to both direct and external disturbances under specific conditions, it has the following drawbacks: conventional magnetorheological elastomer vibration isolation mechanisms can only perform positive stiffness control, while special magnetorheological elastomer vibration isolation mechanisms can perform bidirectional stiffness control, but its stiffness control is still positive control, only within the range of device stiffness control. Even if the initial stiffness is set to the intermediate stiffness, its minimum stiffness is still relatively large, and negative stiffness is not achieved. If a permanent magnet device is used to achieve magnetic field bias, the introduction of permanent magnet materials will lead to poor durability.

[0007] In summary, current magnetorheological elastomer vibration isolation mechanisms have high stiffness values ​​and can only be positively controlled, making it difficult to negatively control the stiffness. Consequently, they are unable to achieve efficient vibration isolation and stabilization for equipment that is simultaneously subjected to direct and external disturbances. Summary of the Invention

[0008] The purpose of this invention is to provide a magnetically controlled negative stiffness adjustment method and actuator to solve the technical problem that the current magnetorheological elastomer vibration isolation mechanism has a high stiffness value and can only be positively controlled, making it difficult to control the stiffness negatively, and thus making it difficult to achieve efficient vibration isolation and stabilization for equipment with both direct and external disturbances.

[0009] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0010] Firstly, based on the technical problems solved above, this invention discloses a method for adjusting magnetically controlled negative stiffness, comprising the following steps:

[0011] S1. Two magnetorheological elastomer units are set up respectively, and the two magnetorheological elastomer units are connected by rigid components.

[0012] S2. Apply a pre-compression force perpendicular to the two magnetorheological elastomer units to the rigid component, so that deformation and pre-shear force are generated in the direction of the line connecting the two magnetorheological elastomer units respectively, and negative stiffness force is generated in the direction perpendicular to the line connecting the two magnetorheological elastomer units.

[0013] S3. Adjustable magnetic fields of the same magnitude are set on the two magnetorheological elastomer units respectively. By adjusting the magnitude of the magnetic field, the negative stiffness force generated by the two magnetorheological elastomers can be controlled.

[0014] The magnetically controlled negative stiffness adjustment method disclosed in this invention utilizes a pre-sheared magnetorheological elastomer unit to provide negative stiffness force. By adjusting the magnitude of the magnetic field at the magnetorheological elastomer unit, the shear modulus of the magnetorheological elastomer unit can be adjusted, thereby adaptively controlling the magnitude of the negative stiffness force of the mechanism.

[0015] Preferably, in step S3, setting adjustable magnetic fields of the same magnitude on the two magnetorheological elastomer units means setting a first fixed magnetic guide plate and a second fixed magnetic guide plate at the upper and lower ends of the two magnetorheological elastomer units respectively. Excitation coils are wound in the middle of the first fixed magnetic guide plate and the second fixed magnetic guide plate. The excitation coils are used to pass current to generate a magnetic field. The currents passed through the two excitation coils are equal in magnitude and in the same direction.

[0016] Preferably, in step S3, the ability to control the negative stiffness force generated by the two magnetorheological elastomers by adjusting the magnitude of the magnetic field means that when the current in the excitation coil is increased, the magnetic field generated in the magnetorheological elastomer unit can be increased, thereby increasing the modulus of the magnetorheological elastomer and the pre-shear force, and ultimately increasing the negative stiffness force of the magnetorheological elastomer body.

[0017] Secondly, the present invention also discloses a magnetically controlled negative stiffness actuator for implementing the magnetically controlled negative stiffness adjustment method described above, comprising a moving unit and a stator unit. The moving unit includes a first magnetorheological elastomer unit and a second magnetorheological elastomer unit. The first magnetorheological elastomer unit is driven to one end of a load connector via a first transmission link, and the other end of the load connector is driven to the second magnetorheological elastomer unit via a second transmission link.

[0018] The stator unit includes a first fixed magnetic plate and a second fixed magnetic plate;

[0019] The two ends of the first fixed magnetic plate are respectively fixedly connected to the top ends of the first magnetorheological elastomer unit and the second magnetorheological elastomer unit;

[0020] A first winding shaft is fixed in the middle of the first fixed magnetic plate, and a first excitation coil is wound around the outer periphery of the first winding shaft;

[0021] The two ends of the second fixed magnetic plate are respectively fixedly connected to the bottom ends of the first magnetorheological elastomer unit and the second magnetorheological elastomer unit;

[0022] A second winding shaft is fixed in the middle of the second fixed magnetic plate, and a second excitation coil is wound around the outer circumference of the second winding shaft;

[0023] There is a gap between the first excitation coil and the second excitation coil to accommodate the load connector;

[0024] In the initial state, the load connector is located outside the gap. In the working state, the load connector is pushed into the gap by an external force. The magnetorheological elastomers in the first and second magnetorheological elastomer units are pre-sheared and deformed outward, causing the magnetically controlled negative stiffness actuator to generate a negative stiffness force.

[0025] Preferably, the first magnetorheological elastomer unit is provided with a first connecting end, which is rotatably connected to one end of the first conductive link via a first ball bearing; the other end of the first conductive link is rotatably connected to one end of the load connector via a second ball bearing.

[0026] The second magnetorheological elastomer unit is provided with a second connecting end, which is rotatably connected to one end of the second conductive link through a third ball bearing; the other end of the second conductive link is rotatably connected to the other end of the load connector through a fourth ball bearing.

[0027] In this way, when the load connector receives pre-compression, the load connector can drive the first and second transmission links to move, thereby pushing the first and second magnetorheological elastomer units to deform and generate pre-shear force.

[0028] Preferably, the first magnetorheological elastomer unit includes a first intermediate connector, the first connecting end is located on the first intermediate connector, the first intermediate connector is a plate-shaped structure, and a first stacked magnetorheological elastomer and a second stacked magnetorheological elastomer are symmetrically fixed on both sides of the plate-shaped structure of the first intermediate connector.

[0029] A first stacked steel sheet is fixed on the side of the first stacked magnetorheological elastomer away from the first intermediate connector, and the other side of the first stacked steel sheet is fixedly connected to one end of the first fixed magnetic conductive plate.

[0030] A second layered steel sheet is fixed on the side of the second layered magnetorheological elastomer away from the first intermediate connector, and the other side of the second layered steel sheet is fixedly connected to one end of the second fixed magnetic guide plate.

[0031] The symmetrically distributed first and second layered magnetorheological elastomers can deform uniformly when the first intermediate connector is subjected to force, thereby generating a uniform pre-shear force.

[0032] Preferably, the second magnetorheological elastomer unit includes a second intermediate connector, the second connecting end is located on the second intermediate connector, the second intermediate connector is a plate-like structure, and a third stacked magnetorheological elastomer and a fourth stacked magnetorheological elastomer are symmetrically fixed on both sides of the plate-like structure of the second intermediate connector.

[0033] A third layer of steel sheet is fixed on the side of the third layer of magnetorheological elastomer away from the second intermediate connector, and the other side of the third layer of steel sheet is fixedly connected to the other end of the first fixed magnetic guide plate.

[0034] A fourth layer of steel sheet is fixed on the side of the fourth layer of magnetorheological elastomer away from the second intermediate connector, and the other side of the fourth layer of steel sheet is fixedly connected to the other end of the second fixed magnetic guide plate.

[0035] The symmetrically distributed third and fourth layer magnetorheological elastomers can deform uniformly when the second intermediate connector is subjected to force, thereby generating a uniform pre-shear force.

[0036] Preferably, the magnetically controlled negative stiffness actuator has a symmetrical structure, wherein the first excitation coil and the second excitation coil are symmetrically distributed vertically and have the same number of windings; the first transmission link and the second transmission link are symmetrically distributed around the first winding axis and the second winding axis and have equal lengths; the first magnetorheological elastomer unit and the second magnetorheological elastomer unit are symmetrically arranged horizontally around the first winding axis and the second winding axis.

[0037] Preferably, the current applied to the first excitation coil and the second excitation coil is in the same direction.

[0038] Applying current to the excitation coil can generate magnetic fields at the first and second magnetorheological elastomer units, respectively, thereby adjusting the shear modulus of the magnetorheological elastomer material and adaptively controlling the magnitude of the negative stiffness force of the mechanism.

[0039] The optimized solution involves connecting the present invention in parallel with a positive stiffness mechanism, and connecting the magnetically controlled negative stiffness actuator in parallel with a positive stiffness mechanism. The positive stiffness mechanism is installed on the load connector, which can achieve the characteristics of high stiffness in the initial state and ultra-low stiffness in the control state of the composite mechanism, even reaching near-zero stiffness, thereby realizing the mechanism's efficient vibration isolation and stabilization integrated function.

[0040] The present invention has the following beneficial effects: The magnetically controlled negative stiffness adjustment method disclosed in this invention utilizes a pre-sheared magnetorheological elastomer unit to provide negative stiffness force. By adjusting the magnetic field magnitude at the magnetorheological elastomer unit, the shear modulus of the magnetorheological elastomer unit can be adjusted, thereby adaptively controlling the magnitude of the negative stiffness force of the mechanism; The magnetically controlled negative stiffness actuator disclosed in this invention utilizes only the magnetorheological elastomer and the symmetrical structural geometry to achieve negative stiffness control of the magnetorheological structure, possessing simple structure and adaptive controllability characteristics. Its stiffness is negative under normal conditions, and its negative stiffness value can be further increased through electromagnetic field control; The present invention can solve the technical problem that the current magnetorheological elastomer vibration isolation mechanism has a high stiffness value and can only be positively controlled, making it difficult to perform negative stiffness control, and thus difficult to achieve efficient vibration isolation and stabilization for equipment with both direct and external disturbances. Attached Figure Description

[0041] To make the objectives, technical solutions, and advantages of the invention clearer, the invention will now be described in further detail with reference to the accompanying drawings, wherein:

[0042] Figure 1 This is a schematic diagram of the magnetically controlled negative stiffness actuator of the present invention.

[0043] Figure 2 This is a schematic diagram of the structure of the magnetically controlled negative stiffness actuator of the present invention after receiving pre-compression.

[0044] Figure 3 This is a cross-sectional view of the magnetically controlled negative stiffness actuator of the present invention.

[0045] Figure 4 This is an enlarged view of the first magnetorheological elastomer unit structure of the present invention.

[0046] Figure 5 This is an enlarged view of the second magnetorheological elastomer unit structure of the present invention.

[0047] Figure 6 This is a top-view schematic diagram of a simplified model of a magnetically controlled negative stiffness actuator according to an embodiment of the present invention, showing the actuator under no pre-compression force.

[0048] Figure 7 This is a top-view schematic diagram of the pre-compression force on a simplified model of the magnetically controlled negative stiffness actuator according to an embodiment of the present invention.

[0049] Figure 8This is a top-view schematic diagram of the generation of negative stiffness force in a simplified model of the magnetically controlled negative stiffness actuator according to an embodiment of the present invention.

[0050] Figure 9 This is a schematic diagram of the composite structure of the magnetically controlled negative stiffness actuator and the positive stiffness mechanism connected in parallel according to the present invention.

[0051] Figure 10 This is a schematic diagram of the positive stiffness mechanism of the present invention.

[0052] Explanation of reference numerals in the attached figures:

[0053] 100. First unit; 101. First layered magnetorheological elastomer; 102. First layered steel sheet; 103. First intermediate connector; 104. Second layered magnetorheological elastomer; 105. Second layered steel sheet; 200. Second unit; 201. Third layered magnetorheological elastomer; 202. Third layered steel sheet; 203. Second intermediate connector; 204. Fourth layered magnetorheological elastomer; 205. Fourth layered steel sheet; 301. First conductive link; 302. First ball bearing; 3 03. Second ball bearing; 304. Load connector; 305. Second transmission link; 306. Third ball bearing; 307. Fourth ball bearing; 308. Insertion hole; 401. First excitation coil; 402. Second excitation coil; 501. First fixed magnetic guide plate; 502. First winding shaft; 503. Second fixed magnetic guide plate; 504. Second winding shaft; 600. Stiffness mechanism; 601. Rubber pad; 602. Metal sheet; 603. Connecting plate; 604. Insertion post. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0055] It should be noted that similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the figures, or the orientation or positional relationship commonly used when the product is in use. They are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance. In addition, the terms "horizontal," "vertical," etc., do not indicate that the component is required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted. In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0056] This invention can be applied to equipment that simultaneously experiences direct and external disturbances and requires efficient vibration isolation and stabilization. It solves the technical problem that current magnetorheological elastomer vibration isolation mechanisms have high stiffness values ​​and can only be positively controlled, making it difficult to achieve negative stiffness control and thus difficult to achieve efficient vibration isolation and stabilization for equipment simultaneously experiencing direct and external disturbances.

[0057] Firstly, based on the technical problems solved above, this invention discloses a method for adjusting magnetically controlled negative stiffness, comprising the following steps:

[0058] S1. Two magnetorheological elastomer units are set up respectively, and the two magnetorheological elastomer units are connected by rigid components.

[0059] S2. Apply a pre-compression force perpendicular to the two magnetorheological elastomer units to the rigid component, so that deformation and pre-shear force are generated in the direction of the line connecting the two magnetorheological elastomer units respectively, and negative stiffness force is generated in the direction perpendicular to the line connecting the two magnetorheological elastomer units.

[0060] S3. Adjustable magnetic fields of the same magnitude are set on the two magnetorheological elastomer units respectively. By adjusting the magnitude of the magnetic field, the negative stiffness force generated by the two magnetorheological elastomers can be controlled.

[0061] The magnetically controlled negative stiffness adjustment method disclosed in this invention utilizes a pre-sheared magnetorheological elastomer unit to provide negative stiffness force. By adjusting the magnitude of the magnetic field at the magnetorheological elastomer unit, the shear modulus of the magnetorheological elastomer unit can be adjusted, thereby adaptively controlling the magnitude of the negative stiffness force of the mechanism.

[0062] Preferably, in step S3, setting adjustable magnetic fields of the same magnitude on the two magnetorheological elastomer units means setting a first fixed magnetic guide plate and a second fixed magnetic guide plate at the upper and lower ends of the two magnetorheological elastomer units respectively. Excitation coils are wound in the middle of the first fixed magnetic guide plate and the second fixed magnetic guide plate. The excitation coils are used to pass current to generate a magnetic field. The currents passed through the two excitation coils are equal in magnitude and in the same direction.

[0063] Preferably, in step S3, the ability to control the negative stiffness force generated by the two magnetorheological elastomers by adjusting the magnitude of the magnetic field means that when the current in the excitation coil is increased, the magnetic field generated in the magnetorheological elastomer unit can be increased, thereby increasing the modulus of the magnetorheological elastomer and the pre-shear force, and ultimately increasing the negative stiffness force of the magnetorheological elastomer body.

[0064] Secondly, this invention also discloses a magnetically controlled negative stiffness actuator, please refer to [link to relevant documentation]. Figure 1 The magnetically controlled negative stiffness adjustment method described above includes a moving unit and a stator unit. The moving unit includes a first magnetorheological elastomer unit and a second magnetorheological elastomer unit. The first magnetorheological elastomer unit is connected to one end of the load connector 304 via a first transmission link 301, and the other end of the load connector 304 is connected to the second magnetorheological elastomer unit via a second transmission link 305.

[0065] The stator unit includes a first fixed magnetic plate 501 and a second fixed magnetic plate 503;

[0066] The two ends of the first fixed magnetic plate 501 are fixedly connected to the top ends of the first magnetorheological elastomer unit and the second magnetorheological elastomer unit, respectively.

[0067] A first winding shaft 502 is fixed in the middle of the first fixed magnetic plate 501, and a first excitation coil 401 is wound around the outer periphery of the first winding shaft 502.

[0068] The two ends of the second fixed magnetic plate 503 are respectively fixedly connected to the bottom ends of the first magnetorheological elastomer unit and the second magnetorheological elastomer unit.

[0069] The second fixed magnetic plate 503 has a second winding shaft 504 fixed in the middle, and a second excitation coil 402 is wound around the outer periphery of the second winding shaft 504;

[0070] There is a gap between the first excitation coil 401 and the second excitation coil 402 to accommodate the load connector 304.

[0071] In the initial state, the load connector 304 is located outside the gap. In the working state, the load connector 304 is pushed into the gap by an external force. The magnetorheological elastomers in the first magnetorheological elastomer unit and the second magnetorheological elastomer unit are pre-sheared and deformed outward, causing the magnetically controlled negative stiffness actuator to generate a negative stiffness force.

[0072] For preference, please refer to Figures 2 to 5 The first magnetorheological elastomer unit is provided with a first connecting end, which is rotatably connected to one end of the first conductive link 301 through a first ball bearing 302; the other end of the first conductive link 301 is rotatably connected to one end of the load connector 304 through a second ball bearing 303.

[0073] The second magnetorheological elastomer unit is provided with a second connecting end, which is rotatably connected to one end of the second conductive link 305 via a third ball bearing 306; the other end of the second conductive link 305 is rotatably connected to the other end of the load connector 304 via a fourth ball bearing 307.

[0074] In this way, when the load connector 304 receives pre-compression, the load connector 304 can drive the first transmission link 301 and the second transmission link 305 to move, thereby pushing the first magnetorheological elastomer unit and the second magnetorheological elastomer unit to deform and generate pre-shear force.

[0075] For preference, please refer to Figure 4 The first magnetorheological elastomer unit includes a first intermediate connector 103, the first connecting end is located on the first intermediate connector 103, the first intermediate connector 103 is a plate-shaped structure, and a first stacked magnetorheological elastomer 101 and a second stacked magnetorheological elastomer 104 are symmetrically fixed on both sides of the plate-shaped structure of the first intermediate connector 103, respectively.

[0076] A first stacked steel sheet 102 is fixed on the side of the first stacked magnetorheological elastomer 101 away from the first intermediate connector 103, and the other side of the first stacked steel sheet 102 is fixedly connected to one end of the first fixed magnetic conductive plate 501.

[0077] A second layered steel sheet 105 is fixed on the side of the second layered magnetorheological elastomer 104 away from the first intermediate connector 103, and the other side of the second layered steel sheet 105 is fixedly connected to one end of the second fixed magnetic plate 503.

[0078] The symmetrically distributed first layered magnetorheological elastomer 101 and second layered magnetorheological elastomer 104 can deform uniformly when the first intermediate connector 103 is subjected to force, thereby generating a uniform pre-shear force.

[0079] For preference, please refer to Figure 5 The second magnetorheological elastomer unit includes a second intermediate connector 203, the second connecting end is located on the second intermediate connector 203, the second intermediate connector 203 is a plate-shaped structure, and a third stacked magnetorheological elastomer 201 and a fourth stacked magnetorheological elastomer 204 are symmetrically fixed on both sides of the plate-shaped structure of the second intermediate connector 203, respectively.

[0080] A third-layer steel sheet 202 is fixed on the side of the third-layer magnetorheological elastomer 201 away from the second intermediate connector 203, and the other side of the third-layer steel sheet 202 is fixedly connected to the other end of the first fixed magnetic guide plate 501.

[0081] A fourth layer steel sheet 205 is fixed on the side of the fourth layer magnetorheological elastomer 204 away from the second intermediate connector 203, and the other side of the fourth layer steel sheet 205 is fixedly connected to the other end of the second fixed magnetic guide plate 503.

[0082] The symmetrically distributed third-layer magnetorheological elastomer 201 and fourth-layer magnetorheological elastomer 204 can deform uniformly when the second intermediate connector 203 is subjected to force, thereby generating a uniform pre-shear force.

[0083] All four magnetorheological elastomers mentioned above can undergo elastic deformation and can also change their physical properties under the action of an external magnetic field, exhibiting different stiffness and damping characteristics.

[0084] For preference, please refer to Figure 1 The magnetically controlled negative stiffness actuator has a symmetrical structure. The first excitation coil 401 and the second excitation coil 402 are symmetrically distributed vertically and have the same number of coils. The first transmission link 301 and the second transmission link 305 are symmetrically distributed around the first winding shaft 502 and the second winding shaft 504 and have the same length. The first magnetorheological elastomer unit and the second magnetorheological elastomer unit are symmetrically arranged horizontally around the first winding shaft 502 and the second winding shaft 504.

[0085] Preferably, the current applied to the first excitation coil 401 and the second excitation coil 402 is in the same direction.

[0086] Applying current to the excitation coil can generate magnetic fields at the first and second magnetorheological elastomer units, respectively, thereby adjusting the shear modulus of the magnetorheological elastomer material and adaptively controlling the magnitude of the negative stiffness force of the mechanism.

[0087] For preference, please refer to Figure 9 The present invention is connected in parallel with a positive stiffness mechanism 600, and a magnetically controlled negative stiffness actuator is connected in parallel with a positive stiffness mechanism 600. The positive stiffness mechanism 600 is installed on the load connector 304, which can realize the characteristics of high stiffness in the initial state and ultra-low stiffness in the control state of the composite mechanism, and even reach quasi-zero stiffness, so as to realize the efficient vibration isolation and stabilization integrated function of the mechanism.

[0088] Preferably, the positive stiffness mechanism 600 employs a laminated rubber vibration isolation unit; please refer to [link / reference]. Figure 10 The laminated rubber vibration isolation unit includes multiple layers of rubber sheets 601 and multiple layers of metal sheets 602. The rubber sheets 601 and metal sheets 602 are alternately stacked and bonded together to form a columnar structure with vibration isolation and buffering capabilities. The positive stiffness mechanism 600 also includes a connecting plate 603. The connecting plate 603 is located on top of the alternately stacked and bonded rubber sheets 601 and metal sheets 602. The connecting plate 603 is provided with a plug-in post 604, and the corresponding load connector 304 is provided with a plug hole. The plug-in post 604 is plugged into the plug hole to realize the installation of the positive stiffness mechanism 600 on the load connector 304.

[0089] Its working principle is as follows: When the laminated rubber vibration isolation unit is subjected to external vibration or impact, the rubber sheet of the vibration isolation unit will be subjected to shear force, which will cause the rubber to undergo elastic deformation. Due to the high softness and low hardness of the rubber, it can effectively absorb and disperse the vibration energy transmitted by the structure.

[0090] The working process of this invention is as follows: In the initial state, the first and second magnetorheological elastomer units are not pre-sheared, and the mechanism has no negative stiffness characteristics. Pressure is applied to the load connector 304, and the first and second magnetorheological elastomer units are subjected to lateral pre-compression. After lateral pre-compression, each stacked magnetorheological elastomer in the first and second magnetorheological elastomer units is subjected to pre-shearing. At this time, the mechanism exhibits negative stiffness characteristics in the pre-compression direction, and its negative stiffness force is provided by the pre-sheared first and second magnetorheological elastomer units; simultaneously... In the pre-shear state, a closed magnetic circuit is formed between the first magnetorheological elastomer unit and the first fixed magnetic plate 501, and between the second magnetorheological elastomer unit and the second fixed magnetic plate 503. Current is applied to the first excitation coil 401 and the second excitation coil 402 respectively, forming a controllable magnetic field in the first and second magnetorheological elastomer units. By increasing the magnetic field of the first and second magnetorheological elastomer units, the modulus of each magnetorheological elastomer is increased, thereby increasing the pre-shear force and ultimately increasing the negative stiffness value of the mechanism, realizing adaptive control of the magnitude of the negative stiffness force of the mechanism.

[0091] The magnetically controlled negative stiffness adjustment method and actuator disclosed in this invention have the following technical effects: To overcome the shortcomings of existing magnetorheological elastomer vibration isolation mechanisms, this invention proposes a magnetically controlled negative stiffness actuator. This invention utilizes only the magnetorheological elastomer and structural geometric features to achieve negative stiffness control of the magnetorheological structure, possessing simple structure and adaptive controllability. Its stiffness is negative under normal conditions, and its negative stiffness value can be further increased through electromagnetic field control. This solves the technical problem that current magnetorheological elastomer vibration isolation mechanisms have high stiffness values ​​and can only be positively controlled, making it difficult to achieve negative stiffness control, and thus difficult to achieve efficient vibration isolation and stabilization for equipment with both direct and external disturbances. The negative stiffness actuator is controllable and adjustable, simple in structure, and low in energy consumption, and can be used in engineering applications requiring low-energy, high-stability adaptive negative stiffness forces. Furthermore, by connecting it in parallel with a traditional positive stiffness vibration isolation mechanism, it can achieve high initial stiffness, ultra-low stiffness in the control state, and even near-zero stiffness, ultimately realizing the mechanism's efficient integrated vibration isolation and stabilization function.

[0092] To further illustrate the magnetically controlled negative stiffness actuator of the present invention, the following application embodiments are disclosed.

[0093] This embodiment provides a magnetically controlled negative stiffness actuator with an overall symmetrical structure, including a moving part and a stator. The moving part includes a first magnetorheological elastomer unit and a second magnetorheological elastomer unit. The first magnetorheological elastomer unit is connected to one end of a load connector 304 via a first transmission link 301, and the other end of the load connector 304 is connected to the second magnetorheological elastomer unit via a second transmission link 305.

[0094] The first magnetorheological elastomer unit is provided with a first connecting end, which is rotatably connected to one end of the first conductive link 301 via a first ball bearing 302; the other end of the first conductive link 301 is rotatably connected to one end of the load connector 304 via a second ball bearing 303; the second magnetorheological elastomer unit is provided with a second connecting end, which is rotatably connected to one end of the second conductive link 305 via a third ball bearing 306; the other end of the second conductive link 305 is rotatably connected to the other end of the load connector 304 via a fourth ball bearing 307; the first conductive link 301 and the second conductive link 305 are symmetrically distributed about the first winding shaft 502 and the second winding shaft 504, and are of equal length; thus, when the load connector 304 is pre-compressed, the load connector 304 can drive the first conductive link 301 and the second conductive link 305 to move, thereby pushing the first magnetorheological elastomer unit and the second magnetorheological elastomer unit to deform and generate pre-shear force.

[0095] The stator unit includes a first fixed magnetic plate 501 and a second fixed magnetic plate 503;

[0096] The first magnetorheological elastomer unit includes a first intermediate connector 103, the first connecting end is located on the first intermediate connector 103, the first intermediate connector 103 is a plate-shaped structure, and a first stacked magnetorheological elastomer 101 and a second stacked magnetorheological elastomer 104 are symmetrically fixed on both sides of the plate-shaped structure of the first intermediate connector 103, respectively.

[0097] A first stacked steel sheet 102 is fixed on the side of the first stacked magnetorheological elastomer 101 away from the first intermediate connector 103, and the other side of the first stacked steel sheet 102 is fixedly connected to one end of the first fixed magnetic conductive plate 501.

[0098] A second layered steel sheet 105 is fixed on the side of the second layered magnetorheological elastomer 104 away from the first intermediate connector 103, and the other side of the second layered steel sheet 105 is fixedly connected to one end of the second fixed magnetic plate 503.

[0099] The second magnetorheological elastomer unit includes a second intermediate connector 203, the second connecting end is located on the second intermediate connector 203, the second intermediate connector 203 is a plate-shaped structure, and a third stacked magnetorheological elastomer 201 and a fourth stacked magnetorheological elastomer 204 are symmetrically fixed on both sides of the plate-shaped structure of the second intermediate connector 203, respectively.

[0100] A third-layer steel sheet 202 is fixed on the side of the third-layer magnetorheological elastomer 201 away from the second intermediate connector 203, and the other side of the third-layer steel sheet 202 is fixedly connected to the other end of the first fixed magnetic guide plate 501.

[0101] A fourth layer steel sheet 205 is fixed on the side of the fourth layer magnetorheological elastomer 204 away from the second intermediate connector 203, and the other side of the fourth layer steel sheet 205 is fixedly connected to the other end of the second fixed magnetic guide plate 503.

[0102] The symmetrically distributed first-layer magnetorheological elastomer 101 and second-layer magnetorheological elastomer 104 can deform uniformly when the first intermediate connector 103 is subjected to force, thereby generating a uniform pre-shear force; the symmetrically distributed third-layer magnetorheological elastomer 201 and fourth-layer magnetorheological elastomer 204 can deform uniformly when the second intermediate connector 203 is subjected to force, thereby generating a uniform pre-shear force; each of the above magnetorheological elastomers can undergo elastic deformation, and can also change its physical properties under the action of an external magnetic field, exhibiting different stiffness and damping characteristics.

[0103] A first winding shaft 502 is fixed in the middle of the first fixed magnetic plate 501, and a first excitation coil 401 is wound around the outer periphery of the first winding shaft 502; the two ends of the second fixed magnetic plate 503 are fixedly connected to the bottom ends of the first magnetorheological elastomer unit and the second magnetorheological elastomer unit, respectively; a second winding shaft 504 is fixed in the middle of the second fixed magnetic plate 503, and a second excitation coil 402 is wound around the outer periphery of the second winding shaft 504; the first excitation coil 401 and the second excitation coil 402 are symmetrically distributed vertically and have the same number of turns; the first magnetorheological elastomer unit and the second magnetorheological elastomer unit are symmetrically arranged horizontally with the first winding shaft 502 and the second winding shaft 504 as the center; there is a gap between the first excitation coil 401 and the second excitation coil 402 to accommodate the load connector 304.

[0104] In the initial state, the load connector 304 is located outside the gap, the magnetorheological elastomer is not sheared, and the structure has no negative stiffness characteristics;

[0105] In the working state, after pre-compression, each stacked magnetorheological elastomer in the first magnetorheological elastomer unit and the second magnetorheological elastomer unit is subjected to pre-shearing action of the same magnitude but different directions. The load connector 304 is pushed into the gap by external force, so that the connecting holes / pins of the first intermediate connector 103, the second intermediate connector 203, the first conductive link 301, the second conductive link 305, and the load connector 304 are on the same straight line. At this time, the magnetorheological elastomers in the first magnetorheological elastomer unit and the second magnetorheological elastomer unit are pre-sheared and deformed outward.

[0106] Meanwhile, in the pre-shear direction, the magnetically controlled negative stiffness actuator exhibits negative stiffness characteristics, and its negative stiffness force is provided by each stacked magnetorheological elastomer in the first and second magnetorheological elastomer units during pre-shear.

[0107] In addition, by applying currents in the same direction to the first excitation coil 401 and the second excitation coil 402, controllable magnetic fields can be generated at the first magnetorheological elastomer unit and the second magnetorheological elastomer unit, respectively. By increasing the magnetic field of the shear-type laminated magnetorheological elastomer unit, the shear modulus of the magnetorheological elastomer material is increased, thereby increasing the pre-shear force, and finally increasing the negative stiffness value of the magnetically controlled negative stiffness actuator, so as to realize the adaptive control of the magnitude of the negative stiffness force of the magnetically controlled negative stiffness actuator.

[0108] Based on the above structure and working process, Figures 6 to 8 Perform force analysis, Figures 6 to 8 The image shown is a top view of a magnetically controlled negative stiffness actuator, and the figure specifies... Planar coordinate system, as shown in the diagram. The horizontal axis of the coordinate system Extending to the right in a positive direction, Perpendicular to the coordinate system It extends downwards in a positive direction.

[0109] If not pre-compressed, please refer to Figure 6 The structure does not exhibit negative stiffness; for pre-compression, please refer to [reference needed]. Figure 7 The first magnetorheological elastomer unit and the second magnetorheological elastomer unit will provide The force in the direction, wherein the force value of the second magnetorheological elastic element is

[0110] (1);

[0111] In equation (1), The stiffness of the second magnetorheological elastic element is given by [reference]. This represents the pre-compression displacement of the second magnetorheological elastomer unit.

[0112] exist In terms of direction, the first and second magnetorheological elastomer units, which are symmetrical from left to right, provide the same force value but opposite directions, and the resultant force is zero.

[0113] exist After the direction of the disturbance is applied, the first and second transmission links and Direction creates an angle ,make The first magnetorheological elastomer unit and the second magnetorheological elastomer unit output... Directional negative stiffness force and Directional displacement The relationship is as follows:

[0114] (2);

[0115] In equation (2), The stiffness of the first magnetorheological elastomer unit or the second magnetorheological elastomer unit. This refers to the pre-compression displacement of either the first or second magnetorheological elastomer unit. The length of the transmission link. For perturbation excitation force.

[0116] Through force right Taking the derivative, we obtain the structural stiffness as:

[0117] (3);

[0118] right exist Performing a 0th-order Taylor expansion on the position, we obtain

[0119] (4);

[0120] In equation (4), The stiffness of the magnetically controlled negative stiffness actuator can be determined from equation (4). Stiffness of the first magnetorheological elastomer unit or the second magnetorheological elastomer unit Pre-compression displacement of the first magnetorheological elastomer unit or the second magnetorheological elastomer unit Length of the first or second conductive link Related.

[0121] When current is input into the first and second excitation coils of the negative stiffness actuator, a magnetic field is generated at the shear-type laminated magnetorheological elastomer, increasing the modulus of the magnetorheological elastomer material. Consequently, the stiffness of the first and second magnetorheological elastomer units increases. This will increase the pre-compression displacement. and the length of the transmission link Since the applied magnetic current remains unchanged, the negative stiffness force of the negative stiffness actuator will increase. That is, as the applied magnetic control current increases, the negative stiffness force of the negative stiffness actuator in this embodiment will increase, thereby enabling the adjustment of the negative stiffness force of the actuator through magnetic control.

[0122] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Under the teachings of the present invention, modifications can be made to these features and embodiments to adapt to specific situations and materials without departing from the spirit and scope of the invention. The embodiments described in this invention are only a part of the embodiments of the invention, not all of them. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. 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. Therefore, the invention is not limited to the specific embodiments disclosed herein, and 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 present invention.

Claims

1. A method for adjusting magnetically controlled negative stiffness, characterized in that, Applicable to a magnetically controlled negative stiffness actuator, comprising the following steps: S1. Two magnetorheological elastomer units are set up respectively, and the two magnetorheological elastomer units are connected by rigid parts. S2. Apply a pre-compression force perpendicular to the two magnetorheological elastomer units to the rigid component, so that deformation and pre-shear force are generated in the direction of the line connecting the two magnetorheological elastomer units respectively, and negative stiffness force is generated in the direction perpendicular to the line connecting the two magnetorheological elastomer units. S3. Adjustable magnetic fields of the same magnitude are set on the two magnetorheological elastomer units respectively. By adjusting the magnitude of the magnetic field, the negative stiffness force generated by the two magnetorheological elastomers can be controlled. The magnetically controlled negative stiffness actuator includes a moving unit and a stator unit. The moving unit includes a first magnetorheological elastomer unit and a second magnetorheological elastomer unit. The first magnetorheological elastomer unit is connected to one end of the load connector via a first transmission link, and the other end of the load connector is connected to the second magnetorheological elastomer unit via a second transmission link. The stator unit includes a first fixed magnetic plate and a second fixed magnetic plate; The two ends of the first fixed magnetic plate are respectively fixedly connected to the top ends of the first magnetorheological elastomer unit and the second magnetorheological elastomer unit; A first winding shaft is fixed in the middle of the first fixed magnetic plate, and a first excitation coil is wound around the outer periphery of the first winding shaft; The two ends of the second fixed magnetic plate are respectively fixedly connected to the bottom ends of the first magnetorheological elastomer unit and the second magnetorheological elastomer unit; A second winding shaft is fixed in the middle of the second fixed magnetic plate, and a second excitation coil is wound around the outer circumference of the second winding shaft; There is a gap between the first excitation coil and the second excitation coil to accommodate the load connector; In the initial state, the load connector is located outside the gap. In the working state, the load connector is pushed into the gap by an external force. The magnetorheological elastomers in the first and second magnetorheological elastomer units are pre-sheared and deformed outward, causing the magnetically controlled negative stiffness actuator to generate a negative stiffness force.

2. The magnetically controlled negative stiffness adjustment method according to claim 1, characterized in that, In step S3, setting adjustable magnetic fields of the same magnitude on the two magnetorheological elastomer units means setting a first fixed magnetic guide plate and a second fixed magnetic guide plate at the upper and lower ends of the two magnetorheological elastomer units respectively. Excitation coils are wound in the middle of the first fixed magnetic guide plate and the second fixed magnetic guide plate. The excitation coils are used to pass current to generate a magnetic field. The currents passed through the two excitation coils are equal in magnitude and in the same direction.

3. The magnetically controlled negative stiffness adjustment method according to claim 2, characterized in that, In step S3, the ability to control the negative stiffness force generated by the two magnetorheological elastomers by adjusting the magnitude of the magnetic field means that when the current in the excitation coil is increased, the magnetic field generated in the magnetorheological elastomer unit can be increased, thereby increasing the modulus of the magnetorheological elastomer and the pre-shear force, and ultimately increasing the negative stiffness force of the magnetorheological elastomer body.

4. The magnetically controlled negative stiffness adjustment method according to claim 1, characterized in that, The first magnetorheological elastomer unit is provided with a first connecting end, which is rotatably connected to one end of the first conductive link through a first ball bearing; the other end of the first conductive link is rotatably connected to one end of the load connector through a second ball bearing. The second magnetorheological elastomer unit is provided with a second connecting end, which is rotatably connected to one end of the second conductive link via a third ball bearing; the other end of the second conductive link is rotatably connected to the other end of the load connector via a fourth ball bearing. In this way, when the load connector receives pre-compression, the load connector can drive the first and second transmission links to move, thereby pushing the first and second magnetorheological elastomer units to deform and generate pre-shear force.

5. The magnetically controlled negative stiffness adjustment method according to claim 4, characterized in that, The first magnetorheological elastomer unit includes a first intermediate connector, the first connecting end is located on the first intermediate connector, the first intermediate connector is a plate-shaped structure, and a first stacked magnetorheological elastomer and a second stacked magnetorheological elastomer are symmetrically fixed on both sides of the plate-shaped structure of the first intermediate connector. A first stacked steel sheet is fixed on the side of the first stacked magnetorheological elastomer away from the first intermediate connector, and the other side of the first stacked steel sheet is fixedly connected to one end of the first fixed magnetic conductive plate. A second layered steel sheet is fixed on the side of the second layered magnetorheological elastomer away from the first intermediate connector, and the other side of the second layered steel sheet is fixedly connected to one end of the second fixed magnetic guide plate.

6. The magnetically controlled negative stiffness adjustment method according to claim 5, characterized in that, The second magnetorheological elastomer unit includes a second intermediate connector, the second connecting end is located on the second intermediate connector, the second intermediate connector is a plate-like structure, and a third stacked magnetorheological elastomer and a fourth stacked magnetorheological elastomer are symmetrically fixed on both sides of the plate-like structure of the second intermediate connector, respectively. A third layer of steel sheet is fixed on the side of the third layer of magnetorheological elastomer away from the second intermediate connector, and the other side of the third layer of steel sheet is fixedly connected to the other end of the first fixed magnetic guide plate. A fourth layer of steel sheet is fixed on the side of the fourth layer of magnetorheological elastomer away from the second intermediate connector, and the other side of the fourth layer of steel sheet is fixedly connected to the other end of the second fixed magnetic guide plate.

7. The magnetically controlled negative stiffness adjustment method according to claim 6, characterized in that, The magnetically controlled negative stiffness actuator has a symmetrical structure. The first excitation coil and the second excitation coil are symmetrically distributed vertically and have the same number of windings. The first and second transmission links are symmetrically distributed around the first and second winding axes and have equal lengths. The first magnetorheological elastomer unit and the second magnetorheological elastomer unit are symmetrically arranged horizontally around the first and second winding axes.

8. The magnetically controlled negative stiffness adjustment method according to claim 7, characterized in that, The currents applied to the first excitation coil and the second excitation coil are in the same direction.

9. The magnetically controlled negative stiffness adjustment method according to claim 8, characterized in that, A magnetically controlled negative stiffness actuator is connected in parallel with a positive stiffness mechanism, which is mounted on a load connector.

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