Heavy-load precise micro-vibration isolation stiffness regulation and control configuration based on vertical magnetization space electromagnetic array

Abstract

The invention discloses a heavy-load precise micro-vibration isolation rigidity regulation and control configuration based on a vertical magnetization space electromagnetic array, and belongs to the technical field of precise vibration isolation. According to the vertical magnetization space electromagnetic array, 2n + 1 (n > = 1, n belongs to N +) layers are arranged in an array mode in the axial direction, a movable magnetic ring array and a fixed magnetic ring array are coaxially nested to construct a single-side high-flux-density magnetic field, wherein the movable magnetic ring array is composed of vertical magnetization uniform-section magnetic rings between the adjacent layers, and the high negative stiffness characteristic is achieved; and an acceleration feedback control algorithm is adopted to regulate and control the size and the direction of electrifying current in the coil so as to generate precise and controllable excitation magnetic flux and dynamically regulate the negative stiffness value. The vertical magnetization space electromagnetic array and the large-scale air floating micro-vibration isolator are connected in parallel to support the load platform, so that the local low dynamic stiffness characteristic can be generated under variable heavy load, the vibration isolation inherent frequency is effectively reduced, the vibration isolation frequency band is expanded to be close to a full frequency domain, and the vibration isolation efficiency is improved. And an ultra-quiet working environment is provided for tip instruments and equipment such as an ultra-precise photoetching machine, a high-resolution satellite camera and an ultra-precise machine tool, so that the leap-type improvement of the precision of the precise instruments and equipment is powerfully promoted.

Description

Technical Field

[0001] The invention belongs to the technical field of precision vibration isolation, in particular to a heavy-load precision micro-vibration isolation stiffness control configuration based on a vertically magnetized space electromagnetic array. Background Art

[0002] With the rapid iteration and upgrading of large-scale precision processing equipment, measuring instruments and large-scale cutting-edge scientific experimental systems, their processing and measurement accuracy has entered the nanometer and sub-nanometer levels, and their sensitivity to micro-vibrations in the environment has gradually increased. Even low-frequency, micro-vibration interference that cannot be detected by human senses can seriously affect the accuracy of large-scale precision processing equipment, measuring instruments and large-scale cutting-edge scientific experimental systems. Therefore, it is crucial to reduce or isolate environmental vibrations, especially low-frequency, micro-vibrations, which have an impact on the accuracy of high-end precision instruments and equipment in the fields of large-scale precision processing, measurement and cutting-edge scientific experiments.

[0003] Stiffness is the core determining parameter of the vibration isolation bandwidth, which directly affects the effect of the micro-vibration isolation platform in dealing with vibrations of different frequencies. Specifically, the starting vibration isolation frequency is exactly 1.414 times the natural frequency; when the stiffness decreases, the starting vibration isolation frequency decreases accordingly, thereby widening the vibration isolation bandwidth. The relative size of the starting vibration isolation frequency and the external micro-vibration excitation frequency is the key factor in determining whether the vibration excitation is enhanced or weakened. Therefore, by real-time monitoring of the frequency of external micro-vibrations, adaptively adjusting the vibration isolation stiffness, and ensuring that the vibration isolation frequency band fully covers the external micro-vibration range, it has become the key to improving vibration isolation performance.

[0004] The current research focus of stiffness control configurations is mostly on small optical micro-vibration isolation platforms and devices, whose mass is usually limited to between kilograms and hundreds of kilograms. However, facing high-end equipment such as large-scale precision processing equipment, high-precision measuring instruments, and large-scale cutting-edge scientific experimental systems that carry tens of tons to thousands of tons, the stiffness control effect is minimal. In addition, the current stiffness control configuration cannot accurately adjust the vibration isolation parameters in real time, resulting in a vibration isolation effect that is less than expected. Specifically, the design of the stiffness control configuration is often optimized for a specific load mass and excitation frequency, and can only achieve low-frequency vibration isolation under preset load conditions, and the initial vibration isolation frequency is fixed. Once the load mass or excitation frequency changes, the dynamic response characteristics of the vibration isolation system will fluctuate accordingly. In particular, when the excitation frequency is lower than the initial vibration isolation frequency, the vibration isolation platform not only cannot play a vibration isolation role, but may amplify the excitation, posing a potential threat to high-end instruments and equipment. Therefore, for large-scale precision air-floating micro-vibration isolation systems with large loads, large sizes, and structural complexity, how to achieve effective stiffness control has become a core problem in achieving high-performance vibration isolation technology.

[0005] Patent No. CN202010897879.X discloses a bistable nonlinear energy device based on electromagnetic negative stiffness. The upper and lower magnetic rings and the upper and lower coils exert attractive force on the middle magnetic ring to form an online adjustable electromagnetic negative stiffness spring. The electromagnetic negative stiffness spring and the pressure spring are connected in parallel to form a bistable nonlinear energy device. When the coil is not energized, the performance of the permanent magnetic negative stiffness is adjusted by adjusting the distance between the upper and lower magnetic rings and the middle magnetic ring. When the coil is energized, the electromagnetic negative stiffness performance is adjusted in real time by adjusting the current in the upper and lower coils and the distance between the upper and lower coils and the middle magnetic ring. Patent No. CN202211512185.5 discloses a low-frequency vibration isolation device based on linear magnetic negative stiffness, which realizes linear magnetic negative stiffness through three magnetic rings arranged with equal spacing along the axial direction and coaxial annular coils configured outside each permanent magnet, wherein the three annular coils are arranged vertically coaxially and symmetrically to form an attractive electromagnetic negative stiffness mechanism, and the three magnetic rings and three annular coils are arranged vertically coaxially and symmetrically to form a repulsive electromagnetic negative stiffness mechanism, and the coupling of the attractive electromagnetic negative stiffness mechanism and the repulsive electromagnetic negative stiffness mechanism realizes the nonlinear offset of the softening stiffness characteristic and the hardening stiffness characteristic. Patent No. CN202311009285.0 discloses a magnetic vibration isolation device and a vibration isolation method with adjustable stiffness, which realizes the adjustable negative stiffness characteristic through four cubic moving permanent magnets arranged inside the vibration isolator and a pair of cubic permanent magnets and a pair of electromagnets fixedly installed in a cross shape. Among them, the adjustable gap between the moving permanent magnet and the fixed permanent magnet realizes the coarse adjustment of the negative stiffness, and the current in the electromagnet realizes the fine adjustment of the negative stiffness. The above technical solutions are all composed of cubic permanent magnets or annular permanent magnets and other gap array arrangements, which have significant magnetic leakage problems and can provide relatively low negative stiffness values.

[0006] Professor Cui Junning of Harbin Institute of Technology proposed an ultra-low frequency air spring isolator (1. "Air spring isolator based on electromagnetic negative stiffness structure", ZL202010605223.6; 2. Ultra-low frequency air spring isolator based on axially magnetized magnetic ring negative stiffness structure, ZL202010606309.0; 3. Large-load ultra-low frequency air spring isolator based on negative stiffness magnetic spring, ZL202010605236.3; 4. Ultra-low frequency isolator based on vertically magnetized magnetic ring negative stiffness structure, ZL202010605241.4), which uses radially reversed magnetization, axially co-magnetized, and mutually perpendicular magnetization inner and outer magnetic rings to achieve negative stiffness characteristics, and uses the eddy currents generated by the relative motion of the inner and outer magnetic rings to work together with the built-in throttle holes to form an efficient damping mechanism, thereby effectively attenuating vibration energy and improving the stability and vibration isolation performance of the vibration isolation system. Patent No. CN202311375790.7 discloses a high linear magnetic negative stiffness mechanism with stator-motor staggered configuration, which coaxially nests stator magnetic rings and mover magnetic rings with the same excitation direction and repulsive magnetic force, and arranges them in multiple layers along the z direction or alternately in multiple columns along the horizontal direction to increase the negative stiffness value provided by the force between the stator magnetic ring and the mover magnetic ring in the z direction, and improves the linearity of the negative stiffness characteristics by setting an initial bias between the mover magnetic ring and the stator magnetic ring of the same layer. Compared with the control scheme based on the equal gap array arrangement of cubic permanent magnets, the scheme of coaxial nesting of inner and outer magnetic rings with radial reverse magnetization, axial same-direction magnetization, and perpendicular magnetization, and arranging them in equal gap arrays along a certain direction can improve the negative stiffness value. However, in the above technical solution, the stator and mover in the negative stiffness mechanism are both single magnetic rings that are radially magnetized or axially magnetized. For such magnetic rings that are uniformly magnetized in a certain direction, the excitation magnetic fields formed on the inside, outside, upper and lower sides are symmetrical, but only one side of the magnetic field is used, and the other side is idle, resulting in the magnetic field utilization rate of this solution still needs to be optimized, and the negative stiffness value generated has little effect on regulating the stiffness of large-scale precision micro-vibration isolation platforms of tens to thousands of tons. In addition, after the design of the above device is completed, the negative stiffness value cannot be adjusted, and only a specific vibration isolation frequency and vibration attenuation effect under a constant load can be achieved, and it cannot adapt to changes in load mass, excitation frequency and vibration isolation requirements.

[0007] In summary, how to design and implement a device that can flexibly adjust the stiffness of precision micro-vibration isolation under heavy load conditions through structural and principle innovation, effectively expand the vibration isolation frequency band, and enable it to adapt to changes in load mass and excitation frequency, thereby reducing the interference of environmental micro-vibration on precision instruments and equipment, and ensuring the optimal working environment, is of great significance for improving the accuracy of precision instruments and equipment. This innovation not only provides a solid guarantee for the optimization of the working environment of precision instruments and equipment, but also meets the extremely high requirements for accuracy and stability in current and future scientific research exploration and high-end industrial applications, and has important technical breakthroughs and application prospects. Summary of the invention

[0008] The core goal of the present invention is to solve the negative impact of environmental vibration interference on precision instruments and equipment. In view of the current lack of research on heavy-duty precision micro-vibration isolation stiffness control mechanisms, a heavy-duty precision micro-vibration isolation stiffness control configuration based on a vertically magnetized space electromagnetic array is designed. The vertically magnetized space electromagnetic array uses 2n+1 (n≥1, n∈N + ) layers are arranged in an axial array, and the dynamic magnetic ring array and the fixed magnetic ring array, which are composed of equal-section magnetic rings with perpendicular magnetization between adjacent layers, are coaxially nested to construct a single-sided high magnetic field, which effectively weakens the magnetic field strength on the non-working side, and significantly enhances the magnetic field strength on the working side, achieving high negative stiffness characteristics; in addition, the acceleration feedback control algorithm is used to control the magnitude and direction of the current in the coil to generate precisely controllable excitation flux and dynamically adjust the negative stiffness value. The vertically magnetized space electromagnetic array and the large air-floating micro-vibrator are connected in parallel to support the load platform, which can produce local low dynamic stiffness characteristics under variable heavy loads, effectively reduce the natural frequency of vibration isolation, and expand the vibration isolation frequency band to the nearly full frequency domain, providing an "ultra-quiet" working environment for cutting-edge instruments and equipment such as ultra-precision lithography machines, high-resolution satellite cameras, and ultra-precision machine tools, thereby effectively promoting a leap-forward improvement in the accuracy of precision instruments and equipment.

[0009] The technical solution of the present invention is:

[0010] The heavy-load precision micro-vibration isolation stiffness control configuration based on the vertical magnetization space electromagnetic array can produce an adjustable high negative stiffness characteristic sufficient to control the heavy-load precision micro-vibration isolation stiffness of tens of tons to thousands of tons, and expand the vibration isolation frequency band to nearly the entire frequency domain, characterized in that: it includes a load platform, a large air-floating micro-vibrator and a vertical magnetization space electromagnetic array; the large air-floating micro-vibrator includes an upper cover plate, an elastic membrane, a gas tank and compressed gas, the upper cover plate is fixedly connected to the load platform, and forms a closed air chamber with the elastic membrane and the gas tank, and compressed gas is introduced into the closed air chamber; the vertical magnetization space electromagnetic array includes a moving magnetic array mounting part, a moving magnetic ring array, a fixed magnetic ring array, a fixed magnetic array fixing part and a coil which are coaxially installed and arranged in sequence from the axis along the radius outward, the moving magnetic ring array and the fixed magnetic ring array are both composed of 2n+1 layers of equal-section magnetic rings arranged in an axial array and vertically magnetized between adjacent layers, where n≥1, n∈N +, and the heights of the odd-numbered layers of magnetic rings are all equal, the heights of the even-numbered layers of magnetic rings are all equal, and the heights of the magnetic rings in the same layer in the moving magnetic ring array and the fixed magnetic ring array are equal; on the right half of the front section view, the first layer of the moving magnetic ring array and the fixed magnetic ring array are magnetized in the opposite direction in the radial direction, and with each additional layer, the magnetization direction of the moving magnetic ring rotates 90° clockwise, and the magnetization direction of the fixed magnetic ring rotates 90° counterclockwise; the moving magnetic ring array is tightly matched and fixedly installed on the outer side of the moving magnetic array mounting piece, and the moving magnetic array mounting piece is a cylindrical structure with an I-shaped cross-section, the top of which is fixedly connected to the load platform, and the bottom maintains a certain gap with the ground, radially with the fixed magnetic ring array , the fixed magnetic array fixture maintains a certain gap; the fixed magnetic array fixture is a circular ring structure with deep grooves on both inner and outer sides along the circumference, the bottom is fixed, and the top maintains a certain gap with the load platform; the fixed magnetic ring array is tightly fitted and fixedly installed in the deep groove on the inner side of the fixed magnetic array fixture, and the coil is tightly fitted and fixedly installed in the deep groove on the outer side of the fixed magnetic array fixture, and a precisely controllable driving current is passed through it. The driving current is output by the driver, and the driver is driven by a controller loaded with an acceleration feedback control strategy. By adjusting the virtual mass, the negative stiffness value of the vertically magnetized space electromagnetic array is equivalently regulated.

[0011] Preferably, the vertical magnetization space electromagnetic array and the large air-floating isolation micro-vibrator are arranged in adjacent gaps or the vertical magnetization space electromagnetic array is coaxially nested and fixedly installed in the gas tank of the large air-floating isolation micro-vibrator.

[0012] Preferably, the height of the coil is equal to the height of the moving magnetic ring array and the fixed magnetic ring array.

[0013] Preferably, the gap between the bottom of the moving magnetic array mounting piece and the ground and the gap between the top of the fixed magnetic array fixing piece and the load platform are both greater than the sum of the floating height of the large air-floating micro-vibrator and the maximum vibration amplitude of the load platform.

[0014] Preferably, the bottom of the first layer of magnetic rings in the moving magnetic ring array overlaps with the bottom of the first layer of magnetic rings in the fixed magnetic ring array.

[0015] Preferably, the large air-floating micro-vibrator is sealed by a steel ring, an O-ring, a diaphragm or a pressure self-sealing method.

[0016] Preferably, the precisely controllable driving current in the coil is generated by a linear regulator, a linear driver, a switching regulator or a switching driver.

[0017] Preferably, the pressure of the compressed gas is 0.1 MPa to 0.8 MPa.

[0018] Preferably, the radially magnetized magnetic rings in the moving magnetic ring array and the fixed magnetic ring array are composed of a plurality of tile-shaped magnets uniformly magnetized in the radial direction, the number of tile-shaped magnets can be 4, 5, 6, 8, 10, 12 and 15, and the gap between adjacent tile-shaped magnets does not exceed 3°.

[0019] Preferably, the moving magnetic array mounting piece and the fixed magnetic array fixing piece are made of non-magnetic or weakly magnetic aluminum alloy or titanium alloy metal materials.

[0020] The technical innovation and good effects of the present invention are:

[0021] (1) The present invention innovatively proposes a vertical magnetization space electromagnetic array with zero magnetic force and adjustable high negative stiffness characteristics, which can achieve stiffness control for heavy-load precision isolation and expand the vibration isolation frequency band to nearly the entire frequency domain. The vertical magnetization space electromagnetic array uses 2n+1(n≥1, n∈N + ) layers are arranged in an axial array, and the adjacent layers are magnetized with equal cross-section magnetic rings. The dynamic magnetic ring array and the fixed magnetic ring array are coaxially nested to construct a unilateral high magnetic field. The high-amplitude negative stiffness characteristics generated are sufficient to regulate the stiffness parameters of large-scale precision micro-vibration isolation devices weighing tens of tons to thousands of tons; in addition, the overall structure is symmetrical about the n+1th layer of magnetic rings, and the magnetic force on the dynamic magnetic ring array is zero; therefore, when the vertically magnetized space electromagnetic array and the large air-floating micro-vibrator are connected in parallel to support the load platform, the local low dynamic stiffness characteristics can be achieved without affecting the load-bearing mass, effectively expanding the vibration isolation bandwidth, and realizing near full-band vibration isolation, providing a "super-quiet" working environment for cutting-edge instruments and equipment, thereby effectively promoting a leap-forward improvement in the accuracy of precision instruments and equipment. This is one of the innovative points of the present invention that distinguishes it from the prior art.

[0022] (2) The present invention can operate stably in a complex and changeable working environment, and can adapt to changes in the mass and excitation frequency of heavy-duty micro-vibration isolation loads. The vertically magnetized space electromagnetic array coaxially nests the coil with the vertically magnetized moving magnetic ring array and the fixed magnetic ring array, and uses the acceleration feedback control algorithm to precisely control the driving current in the coil, thereby equivalently controlling the negative stiffness value through the adjustment of the virtual mass. It can not only effectively respond to the dynamic characteristics adjustment of the vibration isolation system caused by changes in load mass, but also prevent potential instability and performance degradation. At the same time, when the external excitation frequency changes, the vibration isolation frequency can be adjusted in real time to avoid the resonance area, ensuring that the vibration isolation system is free from interference from the resonance phenomenon, and consolidating the long-term stable operation and high reliability of the vibration isolation system. This is the second innovation that distinguishes the present invention from the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A three-dimensional view of an electromagnetic array in perpendicularly magnetized space;

[0024] Figure 2 It is a front cross-sectional view of a vertically magnetized space electromagnetic array;

[0025] Figure 3 and Figure 4 They are respectively a three-dimensional diagram and a front cross-sectional view of the first embodiment of the heavy-load precision isolation micro-vibration stiffness control configuration based on a vertically magnetized space electromagnetic array;

[0026] Figure 5 and Figure 6 They are respectively a three-dimensional diagram and a front cross-sectional view of the second embodiment of the heavy-load precision isolation micro-vibration stiffness control configuration based on a vertically magnetized space electromagnetic array.

[0027] Explanation of the part numbers in the figure: 1 ground, 2 dynamic magnetic ring array, 3 dynamic magnetic array mounting, 4 fixed magnetic ring array, 5 fixed magnetic array fixing, 6 load platform, 7 vertical magnetization space electromagnetic array, 8 large air-floating micro-vibrator, 9 upper cover, 10 elastic membrane, 11 gas tank, 12 compressed gas, 13 coil. DETAILED DESCRIPTION

[0028] The specific implementation modes of the present invention are described in detail below with reference to the accompanying drawings.

[0029] The heavy-load precision micro-vibration isolation stiffness control configuration based on the vertical magnetization space electromagnetic array can produce an adjustable high negative stiffness characteristic sufficient to control the heavy-load precision micro-vibration isolation stiffness of tens of tons to thousands of tons, and expand the vibration isolation frequency band to nearly the entire frequency domain. It is characterized by: comprising a load platform 6, a large air-floating micro-vibration isolation device 8 and a vertical magnetization space electromagnetic array 7; the large air-floating micro-vibration isolation device 8 comprises an upper cover plate 9, an elastic membrane 10, a gas tank 11 and compressed gas 12, and the upper cover plate 9 is fixedly connected to the load platform 6 The vertical magnetization space electromagnetic array 7 comprises a coaxially mounted moving magnetic array mounting member 3, a moving magnetic ring array 2, a fixed magnetic ring array 4, a fixed magnetic array fixing member 5 and a coil 13, which are arranged in sequence along the radius from the axis. The moving magnetic ring array 2 and the fixed magnetic ring array 4 are both composed of 2n+1 layers of equal-section magnetic rings arranged in an axial array and perpendicularly magnetized between adjacent layers, wherein n≥1, n∈N +, and the heights of the odd-numbered layers of magnetic rings are all equal, the heights of the even-numbered layers of magnetic rings are all equal, and the heights of the magnetic rings in the same layer in the moving magnetic ring array 2 and the fixed magnetic ring array 4 are equal; the first layer of the moving magnetic ring array 2 and the fixed magnetic ring array 4 are magnetized in the opposite direction in the radial direction, and on the right half of the front cross-sectional view, with each additional layer, the magnetization direction of the moving magnetic ring rotates 90° clockwise, and the magnetization direction of the fixed magnetic ring rotates 90° counterclockwise; the moving magnetic ring array 2 is tightly matched and fixedly mounted on the outer side of the moving magnetic array mounting member 3, and the moving magnetic array mounting member 3 is a cylindrical structure with an I-shaped cross-section, the top of which is fixedly connected to the load platform 6, and the bottom maintains a certain gap with the ground 1, and is radially spaced from the fixed magnetic ring array 4. The fixed magnetic array fixture 5 maintains a certain gap; the fixed magnetic array fixture 5 is a circular ring structure with deep grooves on both the inner and outer sides along the circumference, the bottom is fixed, and the top maintains a certain gap with the load platform 6; the fixed magnetic ring array 4 is tightly fitted and fixedly installed in the deep groove on the inner side of the fixed magnetic array fixture 5, and the coil 13 is tightly fitted and fixedly installed in the deep groove on the outer side of the fixed magnetic array fixture 5, and a precisely controllable driving current is passed therein, and the driving current is output by the driver, and the driver is driven by a controller loaded with an acceleration feedback control strategy. By adjusting the virtual mass, the negative stiffness value of the vertical magnetization space electromagnetic array 7 is equivalently regulated.

[0030] As a specific implementation, the vertical magnetization space electromagnetic array 7 and the large air-floating isolation micro-vibrator 8 are arranged in adjacent gaps or the vertical magnetization space electromagnetic array 7 is coaxially nested and fixedly installed in the gas tank 11 of the large air-floating isolation micro-vibrator 8 .

[0031] As a specific implementation, the height of the coil 13 is equal to the height of the moving magnetic ring array 2 and the fixed magnetic ring array 4 .

[0032] As a specific implementation, the gap between the bottom of the moving magnetic array mounting component 3 and the ground 1 and the gap between the top of the fixed magnetic array fixing component 5 and the load platform 6 are both greater than the sum of the floating height of the large air-floating micro-vibrator 8 and the maximum vibration amplitude of the load platform 6.

[0033] As a specific implementation manner, the bottom of the first layer of magnetic rings in the moving magnetic ring array 2 coincides with the bottom of the first layer of magnetic rings in the fixed magnetic ring array 4 .

[0034] As a specific implementation, the large air-floating micro-vibrator 8 adopts a steel ring seal, an O-type seal, a diaphragm seal or a pressure self-sealing method.

[0035] As a specific implementation, the precisely controllable driving current in the coil 13 is generated by a linear regulator, a linear driver, a switching regulator or a switching driver.

[0036] As a specific implementation, the pressure of the compressed gas 12 is 0.1 MPa to 0.8 MPa.

[0037] As a specific implementation method, the radially magnetized magnetic rings in the moving magnetic ring array 2 and the fixed magnetic ring array 4 are spliced ​​by multiple tile-shaped magnets that are uniformly magnetized radially. The number of tile-shaped magnets can be 4, 5, 6, 8, 10, 12 and 15, and the gap between adjacent tile-shaped magnets does not exceed 3°.

[0038] As a specific implementation, the moving magnetic array mounting member 3 and the fixed magnetic array fixing member 5 are made of non-magnetic or weakly magnetic aluminum alloy or titanium alloy metal materials.

[0039] Combine the following Figure 1 to Figure 4 An embodiment of the present invention is given.

[0040] The heavy-load precision micro-vibration isolation stiffness control configuration based on the vertical magnetization space electromagnetic array is composed of a load platform 6, a vertical magnetization space electromagnetic array 7 and a large air-floating micro-vibrator 8. The vertical magnetization space electromagnetic array 7 and the large air-floating micro-vibrator 8 are arranged in adjacent gaps and support the load platform 6 in parallel. The large air-floating micro-vibrator 8 stably supports the load platform 6 of tens of tons to thousands of tons in an air-floating manner, and effectively isolates vibrations in the medium and high frequency bands. The vertical magnetization space electromagnetic array 7 uses an active and passive composite magnetic levitation method to produce an adjustable high negative stiffness characteristic, and supports the load platform 6 in parallel with the large air-floating micro-vibrator 8. Under the condition of not affecting the load mass, it can produce a locally adjustable low dynamic stiffness characteristic, so as to reduce the natural frequency of the vibration isolation, expand the vibration isolation frequency band to the nearly full frequency domain, and adapt to the changes in the load mass and the excitation frequency, providing an "ultra-quiet" working environment for cutting-edge instruments and equipment such as ultra-precision lithography machines, high-resolution satellite cameras, and ultra-precision machine tools.

[0041] As the core equipment of ultra-precision air-floating micro-vibration isolation technology, the large-scale air-floating micro-vibration isolation device 8 is a non-metallic spring that fills compressed gas 12 in the elastic membrane 10 and uses the compressibility of the gas to achieve elastic support. Structurally, the large-scale air-floating micro-vibration isolation device 8 is composed of an upper cover plate 9, an elastic membrane 10, a gas tank 11 and compressed gas 12. The upper cover plate 9 is fixedly connected to the load platform 6, and forms a closed air chamber with the elastic membrane 10 and the gas tank 11 through a steel ring seal, an O-ring seal, a diaphragm seal or a pressure self-sealing method. A compressed gas 12 of 0.1MPa to 0.8MPa is passed into the closed air chamber. When external micro-vibration interference acts on the large-scale air-floating micro-vibration isolation device 8, the compressed gas 12 in the closed air chamber will be compressed and expanded accordingly according to the frequency and amplitude of the micro-vibration, thereby effectively absorbing and dissipating the vibration energy and achieving the vibration isolation effect. At the same time, by adjusting the pressure of the compressed gas 12 in the closed air chamber, stable support for different load masses and high-performance vibration isolation effects in the medium and high frequency bands can be achieved.

[0042] The vertical magnetization space electromagnetic array 7 includes a moving magnetic array mounting part 3, a moving magnetic ring array 2, a fixed magnetic ring array 4, a fixed magnetic array fixing part 5 and a coil 13 which are coaxially mounted and arranged in sequence from the axis along the radius outward. The moving magnetic ring array 2 is tightly matched and fixedly mounted on the outer side of the moving magnetic array mounting part 3. The moving magnetic array mounting part 3 is a cylindrical structure with an I-shaped cross-section, the top of which is fixedly connected to the load platform 6, and the bottom maintains a gap of 30mm to 100mm with the ground 1, which is greater than the sum of the floating height of the large air-floating micro-vibrator 8 and the maximum vibration amplitude of the load platform 6. The moving magnetic array mounting part 3 maintains a certain gap with the fixed magnetic ring array 4 and the fixed magnetic array fixing part 5 in the radial direction. The fixed magnetic array fixing part 5 is a circular ring structure with deep grooves on both the inner and outer sides along the circumference, the bottom of which is fixed, and the top of which maintains a gap of 30mm to 100mm with the load platform 6, which is greater than the sum of the floating height of the large air-floating micro-vibrator 8 and the maximum vibration amplitude of the load platform 6. The fixed magnetic ring array 4 is tightly matched and fixedly installed in the deep groove on the inner side of the fixed magnetic array fixture 5, and the coil 13 is tightly matched and fixedly installed in the deep groove on the outer side of the fixed magnetic array fixture 5, and a precisely controllable driving current is passed through it. Among them, the dynamic magnetic array mounting part 3 and the fixed magnetic array fixture 5 are non-magnetic or weakly magnetic aluminum alloy and titanium alloy materials, and the magnetic rings are all N44H brand Ru-Fe-B permanent magnets, with a remanence of 13.54kGs, an intrinsic coercive force of 12.66kOe, and a relative magnetic permeability μ r =1.23.

[0043] The first layer of the moving magnetic ring array 2 and the fixed magnetic ring array 4 are magnetized in opposite directions in the radial direction. On the right half of the front cross-sectional view, with each additional layer of magnetic rings, the magnetization direction of the moving magnetic ring rotates 90° clockwise, and the magnetization direction of the fixed magnetic ring rotates 90° counterclockwise. The radially magnetized magnetic rings in the moving magnetic ring array 2 and the fixed magnetic ring array 4 are both composed of 8 42° tile-shaped magnets, and the gap between adjacent tile-shaped magnets is 3°. A precisely controllable drive current generated by a linear regulator, a linear driver, a switching regulator or a switching driver is passed into the coil 13. When the height of the same layer of magnetic rings in the moving magnetic ring array 2 and the fixed magnetic ring array 4 is equal, the negative stiffness value of the vertically magnetized space electromagnetic array 7 is the largest. Compared with the stiffness control configuration composed of coaxial nesting of radially oppositely magnetized magnetic rings, the negative stiffness value can be increased by up to 155 times under the same size conditions; compared with the stiffness control configuration composed of coaxial nesting of axially same-direction magnetized magnetic rings, the negative stiffness value can be increased by up to 21.4 times under the same size conditions.

[0044] Since the number of layers of the moving magnetic ring array 2 and the fixed magnetic ring array 4 satisfies 2n+1 (n≥1, n∈N +), the overall structure is symmetrical about the n+1th layer of magnetic rings, and the magnetic force on the moving magnetic ring array 2 is zero, and it is in a state of equilibrium. Under the excitation of axial micro-disturbance, the moving magnetic ring array 2 and the fixed magnetic ring array 4 will move relative to each other. At this time, the axial equilibrium state of the moving magnetic ring array 2 is broken, while the radial direction is still balanced. The axial magnetic force of the fixed magnetic ring array 4 acting on the moving magnetic ring array 2 is in the same direction as the vibration, causing it to continue to move away from the equilibrium position. Without the action of external force, the balance cannot be restored. In other words, the axial magnetic force of the vertically magnetized space electromagnetic array 7 presents a negative stiffness characteristic. When it is connected in parallel with the large air-floating micro-vibrator 8 to support the load platform 6, it can produce local low dynamic stiffness characteristics under variable heavy loads, effectively reduce the natural frequency of the vibration isolation, and expand the vibration isolation frequency band to nearly the full frequency domain.

[0045] When the inner radius and outer radius of the moving magnetic ring array 2 are 13mm and 64mm respectively, the height of the odd-numbered moving magnetic rings is 20mm, and the height of the even-numbered moving magnetic rings is 34mm; the inner radius and outer radius of the fixed magnetic ring array 4 are 70mm and 100mm respectively, the height of the odd-numbered fixed magnetic rings is 20mm, and the height of the even-numbered fixed magnetic rings is 34mm; the first layer of moving magnetic rings is magnetized along the radius toward the axis, and the first layer of fixed magnetic rings is magnetized from the axis along the radius outward, when the driving current of the coil 13 is zero, the four vertical magnetization spatial electromagnetic arrays 7 with the above-mentioned structural parameters can reduce the stiffness of the 53.13-ton large air-floating micro-vibration isolation platform by 28.40%, increase the attenuation rate of ground random vibration from 70.85% to 75.44%, reduce the peak value of the vibration transmission rate from 15.61dB to 3.94dB, and attenuate by 74.76%, thereby achieving the expansion of the vibration isolation bandwidth and the improvement of the vibration isolation performance. When the load mass or the excitation frequency changes, the controller uses the acceleration feedback control algorithm to analyze and accurately calculate the vibration signal to generate a control voltage. The driver converts the control voltage into a control current of the control coil 13, and then adjusts the excitation magnetic field, changes the negative stiffness value of the vertical magnetization space electromagnetic array 7, so as to match the stiffness parameters of the near full-frequency vibration isolation bandwidth, so that the effective vibration isolation range can include the excitation frequency or match the load mass, thereby achieving the effect of near full-frequency vibration isolation.

[0046] Figure 5 and Figure 6They are respectively a three-dimensional diagram and a front cross-sectional view of the second embodiment of the heavy-load precision isolation micro-vibration stiffness control configuration based on the vertical magnetization space electromagnetic array. Among them, the vertical magnetization space electromagnetic array 7 is coaxially nested and fixedly installed in the gas tank 11, and supports the load platform 6 in parallel with the large air-floating isolation micro-vibrator 8. The top of the dynamic magnetic array mounting part 3 is fixedly connected to the bottom of the upper cover plate 9, and its bottom maintains a gap of 30mm to 100mm with the upper surface of the lower bottom plate of the gas tank 11, which is greater than the sum of the floating height of the large air-floating isolation micro-vibrator 8 and the maximum vibration amplitude of the load platform 6. The bottom of the fixed magnetic array fixing part 5 is fixedly installed in the main air chamber of the large air-floating isolation micro-vibrator 8, and is fixedly connected to the upper surface of the lower bottom plate of the gas tank 11, and its top maintains a gap of 30mm to 100mm with the bottom of the upper cover plate 9.

Claims

1. The heavy-load precision micro-vibration isolation stiffness control configuration based on the vertical magnetization space electromagnetic array can produce adjustable high negative stiffness characteristics sufficient to control the heavy-load precision micro-vibration isolation stiffness of tens of tons to thousands of tons, and expand the vibration isolation frequency band to nearly the full frequency domain, characterized by: The invention comprises a load platform (6), a large air-floating micro-vibrator (8) and a vertical magnetization space electromagnetic array (7); the large air-floating micro-vibrator (8) comprises an upper cover plate (9), an elastic membrane (10), a gas tank (11) and compressed gas (12); the upper cover plate (9) is fixedly connected to the load platform (6) and forms a closed air chamber with the elastic membrane (10) and the gas tank (11); the compressed gas (12) is introduced into the closed air chamber; the vertical magnetization space electromagnetic array (7) comprises a moving magnetic array mounting part (3), a moving magnetic ring array (2), a fixed magnetic ring array (4), a fixed magnetic array fixing part (5) and a coil (13) which are coaxially mounted and sequentially arranged from the axis along the radius outward; the moving magnetic ring array (2) and the fixed magnetic ring array (4) are both composed of 2n+1 layers of magnetic rings of equal cross-section arranged in an axial array and vertically magnetized between adjacent layers, wherein n≥1, n∈N + , and the heights of the odd-numbered layers of magnetic rings are all equal, the heights of the even-numbered layers of magnetic rings are all equal, and the heights of the magnetic rings of the same layer in the moving magnetic ring array (2) and the fixed magnetic ring array (4) are equal; the first layers of the moving magnetic ring array (2) and the fixed magnetic ring array (4) are magnetized in opposite directions in the radial direction, and on the right half of the front cross-sectional view, with each additional layer, the magnetization direction of the moving magnetic ring rotates 90° clockwise, and the magnetization direction of the fixed magnetic ring rotates 90° counterclockwise; the moving magnetic ring array (2) is tightly matched and fixedly mounted on the outer side of the moving magnetic array mounting member (3), and the moving magnetic array mounting member (3) is a cylindrical structure with an I-shaped cross section, the top of which is fixedly connected to the load platform (6), the bottom of which maintains a certain gap with the ground (1), and the radial direction is spaced apart from the fixed magnetic ring array. (4), the fixed magnetic array fixing part (5) maintains a certain gap; the fixed magnetic array fixing part (5) is a circular ring structure with deep grooves on both the inner and outer sides along the circumference, the bottom of which is fixed, and the top of which maintains a certain gap with the load platform (6); the fixed magnetic ring array (4) is tightly matched and fixedly installed in the deep groove on the inner side of the fixed magnetic array fixing part (5), and the coil (13) is tightly matched and fixedly installed in the deep groove on the outer side of the fixed magnetic array fixing part (5), and a precisely controllable driving current is passed through it. The driving current is output by a driver, and the driver is driven by a controller with a loading acceleration feedback control strategy. By adjusting the virtual mass, the negative stiffness value of the vertical magnetization space electromagnetic array (7) is equivalently controlled.

2. The heavy-load precision isolation micro-vibration stiffness control configuration based on the vertical magnetization space electromagnetic array according to claim 1 is characterized by: The vertical magnetization space electromagnetic array (7) and the large air-floating isolation micro-vibrator (8) are arranged in adjacent gaps, or the vertical magnetization space electromagnetic array (7) is coaxially nested and fixedly installed in the gas tank (11) of the large air-floating isolation micro-vibrator (8).

3. The heavy-load precision isolation micro-vibration stiffness control configuration based on the vertical magnetization space electromagnetic array according to claim 1 is characterized by: The height of the coil (13) is equal to the height of the moving magnetic ring array (2) and the fixed magnetic ring array (4).

4. The heavy-load precision isolation micro-vibration stiffness control configuration based on the vertical magnetization space electromagnetic array according to claim 1 is characterized by: The gap between the bottom of the moving magnetic array mounting component (3) and the ground (1) and the gap between the top of the fixed magnetic array fixing component (5) and the load platform (6) are both greater than the sum of the floating height of the large air-floating micro-vibrator (8) and the maximum vibration amplitude of the load platform (6).

5. The heavy-load precision isolation micro-vibration stiffness control configuration based on the vertical magnetization space electromagnetic array according to claims 1 and 3 is characterized in that: The bottom of the first layer of magnetic rings in the moving magnetic ring array (2) overlaps with the bottom of the first layer of magnetic rings in the fixed magnetic ring array (4).

6. The heavy-load precision isolation micro-vibration stiffness control configuration based on the vertical magnetization space electromagnetic array according to claims 1 and 2 is characterized in that: The large air-floating micro-vibrator (8) adopts a steel ring seal, an O-type seal, a diaphragm seal or a pressure self-sealing method.

7. The heavy-load precision isolation micro-vibration stiffness control configuration based on the vertical magnetization space electromagnetic array according to claim 1 is characterized by: The precisely controllable driving current in the coil (13) is generated by a linear regulator, a linear driver, a switching regulator or a switching driver.

8. The heavy-load precision isolation micro-vibration stiffness control configuration based on the vertical magnetization space electromagnetic array according to claim 1 is characterized by: The pressure of the compressed gas (12) is 0.1 MPa to 0.8 MPa.

9. The heavy-load precision isolation micro-vibration stiffness control configuration based on the vertical magnetization space electromagnetic array according to claims 1, 3 and 5 is characterized in that: The radially magnetized magnetic rings in the moving magnetic ring array (2) and the fixed magnetic ring array (4) are formed by splicing a plurality of tile-shaped magnets uniformly magnetized in the radial direction. The number of tile-shaped magnets can be 4, 5, 6, 8, 10, 12 or 15, and the gap between adjacent tile-shaped magnets does not exceed 3°.

10. The heavy-load precision isolation micro-vibration stiffness control configuration based on the vertical magnetization space electromagnetic array according to claim 1 is characterized by: The moving magnetic array mounting piece (3) and the fixed magnetic array fixing piece (5) are made of non-magnetic or weakly magnetic aluminum alloy or titanium alloy metal materials.

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