Six-degree-of-freedom low-frequency microvibration isolator based on vertical magnetization spatial electromagnetic array

Abstract

The six-degree-of-freedom low-frequency vibration isolator based on vertical magnetization spatial electromagnetic array belongs to the technical field of precision vibration isolation, comprising a top plate, a base plate and six sets of low-frequency electromagnetic vibration isolators arranged in a Stewart manner. The vibration isolator can realize low-frequency, ultra-low-frequency and even near-zero-frequency vibration isolation in six degrees of freedom in space, and has high stability and strong adaptability. The vertical magnetization spatial electromagnetic array negative stiffness structure in the low-frequency electromagnetic vibration isolator utilizes coaxially nested double magnetic ring arrays to achieve passive high negative stiffness characteristics, and utilizes the energized coil coaxially nested with the double magnetic ring array to generate a precisely controllable excitation magnetic flux, dynamically adjusting the bias magnetic field and the negative stiffness value, perfectly adapting to the changing needs of different vibration isolation load masses and excitation frequencies, and ensuring stable vibration isolation performance under various working conditions. The coaxially nested vertical magnetization double magnetic ring array enhances the excitation magnetic field on the working side, reduces the magnetic leakage of the low-frequency electromagnetic vibration isolator, and improves the magnetic field utilization rate.

Description

Technical Field

[0001] This invention belongs to the field of precision vibration isolation technology, specifically a six-degree-of-freedom low-frequency vibration isolation micro-vibrator based on a vertically magnetized spatial electromagnetic array. Background Technology

[0002] Low-frequency micro-amplitude vibration interference in the environment has become one of the key issues limiting the improvement of the accuracy of precision instrument assembly, testing, and experimentation. Equipping precision instruments with low-frequency vibration isolators has gradually become a major technical means to suppress environmental micro-vibrations in the field of ultra-precision engineering. Electromagnetic negative stiffness devices are widely used in parallel with positive stiffness isolators to construct adjustable quasi-zero stiffness isolators due to their characteristics of no mechanical friction, compact structure, adjustable stiffness, and ability to dynamically adapt to changes in vibration isolation load mass and excitation frequency. In the field of single-degree-of-freedom vibration isolation, there has been a lot of research on adjustable quasi-zero stiffness isolators. However, in the field of six-degree-of-freedom vibration isolation, which is more in line with reality, research on adjustable six-degree-of-freedom quasi-zero stiffness isolators is scarce.

[0003] Patents ZL201810300899.7, ZL201610834355.X, and ZL201610915703.6 disclose a six-degree-of-freedom micro-vibration isolation platform based on a combination of active and passive action. The technical solution employs high-precision, high-resolution sensors to dynamically monitor the load's motion and controls the actuator to adjust the applied force according to the vibration of the load platform, thereby achieving low-frequency vibration attenuation. The characteristics of this technical solution are: 1) It requires high-precision sensors and linear actuators to achieve accurate monitoring and attenuation of the load's motion, resulting in high cost. 2) It adopts an active negative stiffness structure composed of sensors, controllers, and actuators, leading to high system cost and energy consumption, and poor stability.

[0004] Patent No. ZL201811101215.7 discloses an electromagnetic six-degree-of-freedom variable stiffness vibration isolation system consisting of an upper plate, a base plate, and six electromagnetic vibration isolation units. Each electromagnetic vibration isolation unit includes a permanent magnet and electromagnetic coils arranged outside the permanent magnet. By changing the number of layers of the permanent magnet and coils, and adjusting the current, the strength of the magnetic field generated by the electromagnetic coils and the distribution of magnetic induction lines are altered, thereby achieving adjustable negative stiffness characteristics. This counteracts the positive stiffness of the helical springs, making the system exhibit near-zero stiffness and achieving optimal vibration isolation performance. The technical solution is characterized by: (1) The electromagnetic vibration isolation unit is composed of permanent magnets and electromagnetic coils. It can only generate negative stiffness characteristics under continuous energy input, and the system has high energy consumption; (2) The magnetization direction of the permanent magnets in the electromagnetic vibration isolation unit is the same. Only one side of the magnetic field is utilized, while the other side of the magnetic field is idle. The low magnetic field utilization rate results in a limited negative stiffness value. When applied to vibration isolation platforms with large load or high natural frequency, its stiffness control effect is minimal, and it is difficult to meet the requirements of low frequency, ultra-low frequency or even near-zero frequency vibration isolation.

[0005] Patent No. ZL202011189248.9 discloses a six-degree-of-freedom microvibrator based on an active electromagnetic negative stiffness structure. This structure utilizes coaxially nested double magnetic rings to achieve non-adjustable negative stiffness in the vertical direction. A precisely controllable excitation flux generated by a coil coaxially nested with the double magnetic rings adjusts the bias magnetic field, thereby dynamically adjusting the negative stiffness value to adapt to changes in the vibration isolation load mass and excitation frequency. The key feature of this technical solution is that the bias magnetic field is provided by a fixed magnetic ring, requiring only a small current in the coil to generate the excitation flux to adjust the bias magnetic field, without the need for continuous high energy input, resulting in relatively low system energy consumption. The coaxially nested double magnetic rings employ a co-axial magnetization method, forming symmetrical excitation magnetic fields on the inner and outer sides of the rings. However, only the magnetic field on the outer side of the inner magnetic ring is effectively utilized, while the inner magnetic field remains idle. This design reduces the utilization rate of the magnetic field, resulting in a low negative stiffness value generated by the coaxial double magnetic ring. When facing the vibration isolation requirements of large load and high natural frequency, its stiffness control effect is minimal, and it is difficult or impossible to achieve low-frequency, ultra-low-frequency or even near-zero-frequency vibration isolation effects.

[0006] In summary, the innovation of vibration isolation structure and principle to provide a high magnetic field utilization and low energy consumption six-degree-of-freedom vibration isolator for applications with large load and high natural frequency, so as to achieve low-frequency, ultra-low-frequency and even near-zero-frequency vibration isolation effects under different load masses and excitation frequencies, is of great significance for further reducing the impact of environmental micro-vibration interference on the accuracy of precision instruments and equipment in assembly, testing and experimentation. Summary of the Invention

[0007] The purpose of this invention is to address the problems of high energy consumption and difficulty in generating sufficiently high negative stiffness to achieve low-frequency, ultra-low-frequency, and even near-zero-frequency vibration isolation effects when facing vibration isolation requirements with large loads and high natural frequencies, using existing six-degree-of-freedom quasi-zero stiffness adjustable vibration isolators. This invention proposes a six-degree-of-freedom low-frequency vibration isolator based on a vertically magnetized spatial electromagnetic array. This micro-vibration isolator not only achieves high-performance vibration isolation in six spatial degrees of freedom (translation along the x, y, and z axes and rotation about the x, y, and z axes), but also possesses high stability and strong adaptability. The negative stiffness structure of the vertically magnetized spatial electromagnetic array utilizes 2n+1 (n≥1, n∈N) + The layers are arranged in an axial array, and the vertically magnetized magnetic arrays of equal cross-sections are coaxially nested between adjacent layers. This enhances the excitation magnetic field on the working side, improves the magnetic field utilization rate, and reduces magnetic leakage. Furthermore, the energized coils coaxially nested with the vertically magnetized spatial magnetic ring array generate a precisely controllable excitation flux, and the negative stiffness is dynamically adjusted to adapt to changes in the vibration isolation load mass and excitation frequency.

[0008] The technical solution of this invention is:

[0009] A six-degree-of-freedom low-frequency isolator based on a vertically magnetized spatial electromagnetic array includes an upper plate, a base plate, and six sets of low-frequency electromagnetic isolators arranged in a Stewart configuration connecting the two. The upper plate has three translational degrees of freedom and three rotational degrees of freedom relative to the base plate. The top of each low-frequency electromagnetic isolator is connected to a fixing member at the bottom of the upper plate via an upper flexible hinge, and its bottom is connected to a fixing member at the top of the base plate via a lower flexible hinge. The axes of adjacent low-frequency electromagnetic isolators are perpendicular to each other. Each low-frequency electromagnetic isolator is composed of a negative stiffness structure of a vertically magnetized spatial electromagnetic array and a helical spring connected in parallel. The negative stiffness structure of the vertically magnetized spatial electromagnetic array includes a moving magnetic ring array, a moving magnetic array mounting component, a fixed magnetic ring array, a fixed magnetic array fixing component, a coil, an upper actuator, and a lower connector. The moving magnetic array mounting component, the moving magnetic ring array, the fixed magnetic ring array, the fixed magnetic array fixing component, and the coil are coaxially mounted and arranged sequentially from the axis outwards along the radius, with the overall structure being axially symmetrical. The moving magnetic array mounting component is an annular sleeve, with its top end fixedly connected to the upper actuator via a thread. The bottom is provided with an annular boss, and the boss has an annular groove. The top of the helical spring is coaxially fixed in the annular groove at the bottom of the moving magnetic array mounting component, and the bottom is coaxially nested and fixed in the annular groove at the bottom of the fixed magnetic array fixing component. The moving magnetic ring array is coaxially nested, tightly fitted, and fixedly installed on the outer side of the moving magnetic array mounting component, with a radial gap between it and the fixed magnetic ring array and the fixed magnetic array fixing component. The fixed magnetic array fixing component is an annular sleeve with deep grooves on both the inner and outer sides. The top of the sleeve maintains a certain gap with the upper flexible hinge in the axial direction, and its bottom is fixedly connected to the lower connector by threads. The fixed magnetic ring array is coaxially nested, tightly fitted, and fixedly installed in the deep groove on the inner side of the fixed magnetic array fixing component. The coil is symmetrical about the axial height of the fixed magnetic ring array and is coaxially nested, tightly fitted, and fixedly installed in the deep groove on the outer side of the fixed magnetic array fixing component. Its energizing current is adaptively adjusted by the controller according to the vibration acceleration of each degree of freedom. Both the moving magnetic ring array and the fixed magnetic ring array are composed of 2n+1 (n≥1, n∈N). + The array consists of axially arranged magnetic rings of equal cross-section, with adjacent layers being perpendicularly magnetized. The odd-numbered layers of magnetic rings have the same height, and the even-numbered layers have the same height. The magnetic rings in the same layer of the moving magnetic ring array and the fixed magnetic ring array have the same height. The first layer of magnetic rings in the moving magnetic ring array and the fixed magnetic ring array are magnetized in opposite directions radially, and their bottom surfaces coincide. On the right half of the front 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.

[0010] Preferably, the moving magnetic array mounting component, fixed magnetic ring fixing component, upper actuating component, lower connecting component, upper flexible hinge, lower flexible hinge and helical spring are made of non-magnetic or weakly magnetic aluminum alloy, titanium alloy or austenitic stainless steel.

[0011] Preferably, the precisely controllable drive current in the coil is generated by a linear regulator, a linear driver, a switching regulator, or a switching driver.

[0012] Preferably, the radially magnetized magnetic rings in the moving magnetic ring array and the fixed magnetic ring array are composed of multiple radially uniformly magnetized tile-shaped magnets spliced ​​together. 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°.

[0013] The technical innovation and positive effects of this invention are as follows:

[0014] (1) This technical solution employs a multi-layered, axially arranged array of uniform cross-section magnetic rings, with adjacent layers vertically magnetized. These rings are coaxially nested and connected in parallel with energized coils to achieve adjustable high negative stiffness. This allows the solution to adapt to changes in load weight and excitation frequency, achieving low-frequency, ultra-low-frequency, and even near-zero-frequency vibration isolation under variable load conditions. For heavy-load and high-natural-frequency vibration isolation platforms, the required negative stiffness for low-frequency vibration isolation is higher. This invention uses a multi-layered, axially arranged array of uniform cross-section magnetic rings with vertical magnetization between adjacent layers. This design not only effectively reduces magnetic leakage but also significantly enhances the magnetic field strength on the working side, thus achieving high negative stiffness. Furthermore, the energized coils, coaxially nested with the vertically magnetized magnetic ring array, generate a precisely controllable excitation flux, thereby adjusting the bias magnetic field around the moving magnetic ring array and making the negative stiffness adjustable. Therefore, this invention can adapt to changes in load weight and excitation frequency, and is particularly suitable for achieving low-frequency, ultra-low-frequency, and even near-zero-frequency vibration isolation under variable load conditions. This is one of its key innovations compared to existing technologies.

[0015] (2) This technical solution can achieve multi-degree-of-freedom precision low-frequency vibration isolation under heavy load conditions, creating an "ultra-quiet" working environment for advanced instruments and equipment, and significantly improving the accuracy of the equipment. By using a low-frequency electromagnetic vibration isolator composed of a negative stiffness structure of six vertically magnetized spatial electromagnetic arrays connected in parallel with a helical spring, the local low dynamic stiffness characteristics of six degrees of freedom can be achieved without changing the load-bearing capacity of the helical spring. This effectively reduces the natural frequency of the vibration isolation system and expands the vibration isolation bandwidth, thereby isolating vibrations from six degrees of freedom in space (translation along the x, y, and z axes and rotation around the x, y, and z axes), ensuring the normal operation of precision instruments and maintaining high precision. This is the second innovative point of this invention that distinguishes it from the prior art.

[0016] (3) This invention has the advantages of compact structure, convenient installation, and low maintenance cost. This allows the device to be easily integrated into existing instrument systems, improving the overall performance and reliability of the system. At the same time, the lower maintenance cost also reduces the operating cost and improves the economic efficiency of the device. This is the third innovative point that distinguishes this invention from the prior art. Attached Figure Description

[0017] Figure 1 A three-dimensional model of a six-degree-of-freedom low-frequency isolation micro-vibrator based on a vertically magnetized spatial electromagnetic array;

[0018] Figure 2 A three-dimensional cross-sectional schematic diagram of a low-frequency electromagnetic vibration isolator;

[0019] Figure 3 This is a front sectional view of a low-frequency electromagnetic vibration isolator.

[0020] Figures 4 to 10 A schematic diagram showing the relative positions and magnetization directions of the moving magnetic ring array and the fixed magnetic ring array when 4, 5, 6, 8, 10, 12 and 15 tile-shaped magnets are spliced ​​together to form a radially magnetized magnetic ring.

[0021] Part numbers in the diagram: 1. Moving magnetic ring array; 2. Moving magnetic array mounting component; 3. Fixed magnetic ring array; 4. Fixed magnetic array fixing component; 5. Coil; 61. Upper actuator; 62. Lower connector; 7. Helical spring; 81. Upper flexible hinge; 82. Lower flexible hinge; 9. Upper plate; 10. Base plate; 11. Vertical magnetized spatial electromagnetic array negative stiffness structure; 12. Fixing component; 13. Low-frequency electromagnetic vibration isolator. Detailed Implementation

[0022] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0023] A six-degree-of-freedom low-frequency vibration isolator based on a vertically magnetized spatial electromagnetic array includes an upper plate 9, a base plate 10, and six sets of low-frequency electromagnetic vibration isolators 13 connected to the upper plate 9 in a Stewart arrangement. The upper plate 9 has three translational degrees of freedom and three rotational degrees of freedom relative to the base plate 10. The top of each low-frequency electromagnetic vibration isolator 13 is connected to a fixing member 12 at the bottom of the upper plate 9 via an upper flexible hinge 81, and its bottom is connected to a fixing member 12 at the top of the base plate 10 via a lower flexible hinge 82. The axes of two adjacent low-frequency electromagnetic vibration isolators 13 are perpendicular to each other. Device 13 is composed of a vertically magnetized spatial electromagnetic array negative stiffness structure 11 connected in parallel with a helical spring 7. The vertically magnetized spatial electromagnetic array negative stiffness structure 11 includes a moving magnetic ring array 1, a moving magnetic array mounting component 2, a fixed magnetic ring array 3, a fixed magnetic array fixing component 4, a coil 5, an upper actuator 61, and a lower connector 62. The moving magnetic array mounting component 2, the moving magnetic ring array 1, the fixed magnetic ring array 3, the fixed magnetic array fixing component 4, and the coil 5 are coaxially mounted and arranged sequentially from the axis outward along the radius, with the overall structure being axially symmetrical. The moving magnetic array mounting component 2 is an annular sleeve, with a screw threaded through the top end. The coil spring 7 is fixedly connected to the upper actuator 61, and has an annular boss at the bottom with an annular groove inside the boss. The top end of the coil spring 7 is coaxially fixedly installed in the annular groove at the bottom of the moving magnetic array mounting part 2, and the bottom end is coaxially nested and fixedly installed in the annular groove at the bottom of the fixed magnetic array fixing part 4. The moving magnetic ring array 1 is coaxially nested, tightly fitted, and fixedly installed on the outer side of the moving magnetic array mounting part 2, with a radial gap between it and the fixed magnetic ring array 3 and the fixed magnetic array fixing part 4. The fixed magnetic array fixing part 4 is an annular sleeve with deep grooves on both the inner and outer sides along the circumference, and the top end is connected to the upper actuator 61. The flexible hinge 81 maintains a certain gap in the axial direction, and its bottom is fixedly connected to the lower connector 62 by a thread; the fixed magnetic ring array 3 is coaxially nested, tightly fitted, and fixedly installed in the deep groove inside the fixed magnetic array fixing part 4; the coil 5 is symmetrical about the axial height center of the fixed magnetic ring array 3, and is coaxially nested, tightly fitted, and fixedly installed in the deep groove outside the fixed magnetic array fixing part 4; its energizing current is adaptively adjusted by the controller according to the vibration acceleration of each degree of freedom; both the moving magnetic ring array 1 and the fixed magnetic ring array 3 are composed of 2n+1 (n≥1, n∈N) + The array consists of magnetic rings of equal cross-section arranged in an axial array, with adjacent layers being perpendicularly magnetized. The odd-numbered layers of magnetic rings have the same height, and the even-numbered layers have the same height. The magnetic rings in the same layer of the moving magnetic ring array 1 and the fixed magnetic ring array 3 have the same height. The first layer of magnetic rings in the moving magnetic ring array 1 and the fixed magnetic ring array 3 are magnetized in opposite directions radially, and their bottom surfaces coincide. On the right half of the front 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.

[0024] As a specific implementation, the moving magnetic array mounting component 2, the fixed magnetic array fixing component 4, the upper actuating component 61, the lower connecting component 62, the upper flexible hinge 81, the lower flexible hinge 82, and the helical spring 7 are made of non-magnetic or weakly magnetic aluminum alloy, titanium alloy, or austenitic stainless steel.

[0025] In one specific implementation, the precisely controllable drive current within coil 5 is generated by a linear regulator, a linear driver, a switching regulator, or a switching driver.

[0026] In one specific implementation, the radially magnetized magnetic rings in the moving magnetic ring array 1 and the fixed magnetic ring array 3 are composed of multiple radially uniformly magnetized tile-shaped magnets spliced ​​together. 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°.

[0027] The following is combined Figures 1-3 An embodiment of the present invention is given.

[0028] like Figure 1 As shown, the present invention includes an upper plate 9, a base plate 10, and six sets of low-frequency electromagnetic vibration isolators 13 connected to the upper plate 9 in a Stewart arrangement. The upper plate 9 has three degrees of freedom of translation along the x, y, and z axes and three degrees of freedom of rotation about the x, y, and z axes relative to the base plate 10. The top of the upper actuator 61 of each set of low-frequency electromagnetic vibration isolators 13 is connected to the fixing member 12 at the bottom of the upper plate 9 through four threaded holes evenly distributed on the upper flexible hinge 81. The bottom of the lower connector 62 of each set of low-frequency electromagnetic vibration isolators 13 is connected to the fixing member 12 on the base plate 10 through four threaded holes evenly distributed on the lower flexible hinge 82. The axes of two adjacent sets of low-frequency electromagnetic vibration isolators 13 are perpendicular to each other.

[0029] like Figure 2 and Figure 3As shown, each low-frequency electromagnetic vibration isolator 13 is composed of a vertically magnetized spatial electromagnetic array negative stiffness structure 11 and a helical spring 7 connected in parallel. The vertically magnetized spatial electromagnetic array negative stiffness structure 11 includes a moving magnetic ring array 1, a moving magnetic array mounting component 2, a fixed magnetic ring array 3, a fixed magnetic array fixing component 4, a coil 5, an upper actuator 61, and a lower connector 62. The moving magnetic array mounting component 2, the moving magnetic ring array 1, the fixed magnetic ring array 3, the fixed magnetic array fixing component 4, and the coil 5 are coaxially mounted and arranged sequentially from the axis outward along the radius, with the overall structure being axially symmetrical. The moving magnetic array mounting component 2 is an annular sleeve made of 7075 aluminum alloy. Its top end is fixedly connected to the upper actuator 61 through four threaded holes evenly distributed along the circumference, and an annular boss is provided at the bottom, with an annular groove inside the boss. The positive stiffness characteristic of the helical spring 7 is used to achieve stable support for the vibration isolation load, and its top end... The moving magnetic array 1 is coaxially fixed in the annular groove at the bottom of the moving magnetic array mounting part 2, and coaxially nested and fixed in the annular groove at the bottom of the fixed magnetic array fixing part 4. The moving magnetic ring array 1 is coaxially nested, tightly fitted and fixed in the outer side of the moving magnetic array mounting part 2, with a radial gap of 5mm to 20mm between it and the fixed magnetic ring array 3 and the fixed magnetic array fixing part 4. The fixed magnetic array fixing part 4 is an annular sleeve with deep grooves on both the inner and outer sides. The top end maintains a certain gap with the upper flexible hinge 81 in the axial direction, and its bottom is fixedly connected to the lower connector 62 by threads. The fixed magnetic ring array 3 is coaxially nested, tightly fitted and fixed in the deep groove on the inner side of the fixed magnetic array fixing part 4. The coil 5 is symmetrical about the axial height center of the fixed magnetic ring array 3, and coaxially nested, tightly fitted and fixed in the deep groove on the outer side of the fixed magnetic array fixing part 4.

[0030] Both the moving magnetic ring array 1 and the fixed magnetic ring array 3 are composed of 2n+1 (n≥1, n∈N) +The array consists of uniformly cross-sectional magnetic rings arranged in an axial array, with adjacent layers perpendicularly magnetized. All rings are made of N50 neodymium iron boron, with a remanent magnetic induction of 1.43 T and a relative permeability of 1.03. The inner and outer radii of the moving magnetic ring array 1 are 1.3 mm and 6.4 mm, respectively. The height of odd-numbered moving magnetic rings is 2 mm, and the height of even-numbered moving magnetic rings is 3.4 mm. The inner and outer radii of the fixed magnetic ring array 3 are 7 mm and 10 mm, respectively. The height of odd-numbered fixed magnetic rings is 2 mm, and the height of even-numbered fixed magnetic rings is 3.4 mm. The first layer of the moving magnetic ring array 1 is magnetized radially towards the axis, while the first layer of the fixed magnetic ring array 3 is magnetized radially outward from the axis, with their bottom surfaces coinciding. In the right half of the front sectional view, with each additional layer, the magnetization direction of the moving magnetic rings rotates 90° clockwise, and the magnetization direction of the fixed magnetic rings rotates 90° counterclockwise. When the heights of the magnetic rings in the same layer in the moving magnetic ring array 1 and the fixed magnetic ring array 3 are equal, the negative stiffness value of the vertically magnetized spatial electromagnetic array can be maximized. Compared with the negative stiffness structure composed of coaxially nested radially reverse magnetized magnetic rings, the negative stiffness value can be increased by up to 155 times under the same size conditions. Compared with the negative stiffness structure composed of coaxially nested axially oriented magnetized magnetic rings, the negative stiffness value can be increased by up to 21.4 times under the same size conditions.

[0031] Coil 5 is formed by winding insulated copper enameled wire, with a circular cross-section. Coil 5 is symmetrical about the axial height of the fixed magnetic ring array 3. A precisely controllable drive current, generated by a linear regulator, linear driver, switching regulator, or switching driver, flows through coil 5, with a maximum current density of 5 A / mm². 2 When the vertically magnetized spatial electromagnetic array negative stiffness structure 11 is working, the control signal is amplified by the power amplifier, and the output drive current is applied to the coil 5. According to the law of electromagnetic induction, a precisely controllable excitation flux is generated around the energized coil 5. The excitation flux and the bias magnetic field generated by the fixed magnetic ring array 3 around the moving magnetic ring array 1 are superimposed to form the magnetic field that realizes the negative stiffness characteristic. When a counterclockwise current flows through the coil 5, the magnetic force generated by the excitation flux and the bias magnetic field on the moving magnetic ring array 1 is in the same direction, and both cause the moving magnetic ring array 1 to deviate from the static equilibrium position under external excitation interference. The current in the coil increases the negative stiffness value, and vice versa.

[0032] Since the number of layers of the moving magnetic ring array 1 and the fixed magnetic ring array 3 satisfies 2n+1 (n≥1, n∈N) +The overall structure is symmetrical about the nth layer of magnetic rings. The magnetic force on the moving magnetic ring array 1 is zero, and it is in equilibrium. Under axial micro-perturbation excitation, the moving magnetic ring array 1 will move relative to the fixed magnetic ring array 3. At this time, the axial equilibrium of the moving magnetic ring array 1 is broken, while the radial equilibrium remains. The axial magnetic force of the fixed magnetic ring array 3 on the moving magnetic ring array 1 is in the same direction as the vibration, causing it to continue to move away from the equilibrium position. Without external force, the equilibrium cannot be restored. That is, the axial magnetic force of the vertically magnetized spatial electromagnetic array negative stiffness structure 11 exhibits negative stiffness characteristics. When it is connected in parallel with the helical spring 7 to support the vibration isolation load, the vibration isolation bandwidth can be adjusted by generating negative stiffness characteristics without affecting the load-bearing capacity of the helical spring 7.

[0033] The moving magnetic ring array 1, the fixed magnetic ring array 3, and the energized coil 5 work together to generate adjustable high negative stiffness characteristics, enabling the six-degree-of-freedom low-frequency vibration isolation micro-vibrator to adaptively adjust according to actual working conditions, thereby achieving low-frequency, ultra-low-frequency, and even near-zero-frequency vibration isolation effects. When the load mass or excitation frequency changes, the controller adaptively adjusts the magnitude and direction of the current in coil 5 based on the vibration acceleration of each degree of freedom, precisely controlling the magnitude and direction of the excitation flux. This changes the magnitude and direction of the magnetic force on the moving magnetic ring array 1, adjusting the negative stiffness value to adapt to changes in the vibration isolation load mass and excitation frequency. Specifically, when the load mass increases, the controller adaptively increases the current in coil 5 based on the vibration acceleration of each degree of freedom to enhance the repulsive force of the negative stiffness structure 11 of the vertically magnetized spatial electromagnetic array, thereby providing greater negative stiffness to balance the increased load mass, ensuring that the vibration isolation system can still achieve near-full-frequency isolation bandwidth under a larger load. Furthermore, when the excitation frequency is reduced to near or below the natural frequency of the precision vibration isolation system, the controller adaptively adjusts the magnitude and direction of the current flowing through the coil 5 according to the vibration acceleration of each degree of freedom, so as to enhance the negative stiffness value of the negative stiffness structure 11 of the vertical magnetized spatial electromagnetic array, thereby effectively reducing the natural frequency of the vibration isolation, avoiding the resonance region, ensuring that the vibration isolation system is free from resonance interference, and guaranteeing its long-term stable operation and high reliability.

[0034] The radial magnetization process of a magnetic ring is complex and the magnetization effect cannot be guaranteed. Therefore, it is usually made by splicing together multiple tile-shaped magnets that are uniformly magnetized in the radial direction. Figures 4 to 10 The diagram shows the relative positions and magnetization directions of the moving magnetic ring array 1 and the fixed magnetic ring array 3 when 4, 5, 6, 8, 10, 12 and 15 tile-shaped magnets are spliced ​​together to form a radial magnetized magnetic ring. The gap between adjacent tile-shaped magnets is usually no more than 3° to ensure the continuity and uniformity of the magnetic field.

Claims

1. A six-degree-of-freedom low-frequency isolator based on a vertically magnetized spatial electromagnetic array, comprising an upper plate (9), a base plate (10), and six sets of low-frequency electromagnetic isolators (13) connected to the upper plate (9) in a Stewart arrangement. The upper plate (9) has three translational degrees of freedom and three rotational degrees of freedom relative to the base plate (10). The top of each low-frequency electromagnetic isolator (13) is connected to a fixing member (12) at the bottom of the upper plate (9) via an upper flexible hinge (81), and its bottom is connected to a fixing member (12) at the top of the base plate (10) via a lower flexible hinge (82). The axes of two adjacent low-frequency electromagnetic isolators (13) are perpendicular to each other. The low-frequency electromagnetic vibration isolator (13) is composed of a vertically magnetized spatial electromagnetic array negative stiffness structure (11) and a helical spring (7) connected in parallel. The vertically magnetized spatial electromagnetic array negative stiffness structure (11) includes a moving magnetic ring array (1), a moving magnetic array mounting component (2), a fixed magnetic ring array (3), a fixed magnetic array fixing component (4), a coil (5), an upper actuator (61), and a lower connector (62). The moving magnetic array mounting component (2), the moving magnetic ring array (1), the fixed magnetic ring array (3), the fixed magnetic array fixing component (4), and the coil (5) are coaxially mounted and arranged sequentially from the axis outward along the radius. The structure is axially symmetrical; the moving magnetic array mounting part (2) is an annular sleeve, with its top end fixedly connected to the upper actuator (61) by a thread, and an annular boss provided at the bottom, with an annular groove provided inside the boss; the top end of the helical spring (7) is coaxially fixedly installed in the annular groove at the bottom of the moving magnetic array mounting part (2), and its bottom end is coaxially nested and fixedly installed in the annular groove at the bottom of the fixed magnetic array fixing part (4); the moving magnetic ring array (1) is coaxially nested, tightly fitted, and fixedly installed on the outer side of the moving magnetic array mounting part (2), with a radial gap between it and the fixed magnetic ring array (3) and the fixed magnetic array fixing part (4); the fixed magnetic array fixing part... The fixed component (4) is an annular sleeve with deep grooves on both the inner and outer sides. The top end of the sleeve maintains a certain gap with the upper flexible hinge (81) in the axial direction, and the bottom end is fixedly connected to the lower connector (62) by threads. The magnetic ring array (3) is coaxially nested, tightly fitted, and fixedly installed in the deep groove inside the fixed magnetic array fixed component (4). The coil (5) is symmetrical about the axial height of the fixed magnetic ring array (3) and is coaxially nested, tightly fitted, and fixedly installed in the deep groove outside the fixed magnetic array fixed component (4). Its energizing current is adaptively adjusted by the controller according to the vibration acceleration of each degree of freedom. Both the moving magnetic ring array (1) and the fixed magnetic ring array (3) are composed of 2n+1 (n≥1) layers of magnetic rings with equal cross-sections arranged in an axial array and perpendicularly magnetized between adjacent layers. The odd-numbered layers of magnetic rings have equal heights, and the even-numbered layers of magnetic rings have equal heights. The magnetic rings in the same layer of the moving magnetic ring array (1) and the fixed magnetic ring array (3) have equal heights. The first layer of magnetic rings in the moving magnetic ring array (1) and the fixed magnetic ring array (3) are magnetized in opposite directions radially, and their bottom surfaces coincide. On the right half of the front 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.

2. The six-degree-of-freedom low-frequency isolator based on a vertically magnetized spatial electromagnetic array according to claim 1, characterized in that: The moving magnetic array mounting component (2), the fixed magnetic array fixing component (4), the upper actuating component (61), the lower connecting component (62), the upper flexible hinge (81), the lower flexible hinge (82), and the helical spring (7) are made of non-magnetic or weakly magnetic aluminum alloy, titanium alloy, or austenitic stainless steel.

3. The six-degree-of-freedom low-frequency isolating micro-vibrator based on a vertically magnetized spatial electromagnetic array according to claim 1, characterized in that: The precisely controllable drive current in the coil (5) is generated by a linear regulator, a linear driver, a switching regulator, or a switching driver.

4. The six-degree-of-freedom low-frequency isolator based on a vertically magnetized spatial electromagnetic array according to claim 1, characterized in that: The radially magnetized magnetic rings in the moving magnetic ring array (1) and the fixed magnetic ring array (3) are composed of multiple radially uniformly magnetized tile-shaped magnets spliced ​​together. 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°.

Images