Six-degree-of-freedom low-frequency micro-vibration isolator based on vertical magnetization space electromagnetic array

Abstract

A six-degree-of-freedom low-frequency micro-vibration isolator based on a vertical magnetization space electromagnetic array belongs to the technical field of precise vibration isolation and comprises an upper plate, a base plate and six sets of low-frequency electromagnetic vibration isolators connected with the upper plate and the base plate and arranged in a Stewart mode, low-frequency, ultra-low-frequency and even near-zero-frequency micro-vibration isolation can be achieved in six degrees of freedom in space, and the six-degree-of-freedom low-frequency micro-vibration isolator has high stability and high adaptability. According to the vertical magnetization space electromagnetic array negative stiffness structure in the low-frequency electromagnetic vibration isolator, the passive high negative stiffness characteristic is achieved through a coaxially-nested double-magnetic-ring array, precise and controllable excitation magnetic flux is generated through an electrified coil coaxially nested with the double-magnetic-ring array, and the bias magnetic field and the negative stiffness value are dynamically adjusted; the variable requirements of different vibration isolation load masses and excitation frequencies are perfectly met, and it is ensured that the stable vibration isolation performance can be kept under various working conditions. The coaxially nested vertical magnetization double-magnet ring array enhances the excitation magnetic field of the working side, reduces the magnetic leakage of the low-frequency electromagnetic vibration isolator, and improves the utilization rate of the magnetic field.

Description

Technical Field

[0001] The invention belongs to the technical field of precision vibration isolation, in particular to a six-degree-of-freedom low-frequency micro-vibration isolation device based on a vertically magnetized space electromagnetic array. Background Art

[0002] Low-frequency micro-vibration interference in the environment has become one of the key issues that restrict the improvement of precision in the installation, adjustment, testing and experimental accuracy of precision instruments and equipment. Equipping precision instruments and equipment with low-frequency vibration isolators has gradually become the main 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 stiffness quasi-zero stiffness isolators because of their characteristics such as no mechanical friction, compact structure, adjustable stiffness, and ability to dynamically adapt to changes in the isolation load mass and excitation frequency. In terms of single-degree-of-freedom vibration isolation, there have been many related studies on adjustable stiffness quasi-zero stiffness isolators, but in terms of six-degree-of-freedom vibration isolation, which is more in line with the reality, there is little research on adjustable stiffness six-degree-of-freedom quasi-zero stiffness isolators.

[0003] Patent Nos. ZL201810300899.7, ZL201610834355.X and ZL201610915703.6 disclose a six-degree-of-freedom micro-vibration isolation platform based on active and passive composite action. The technical solution uses high-precision, high-resolution sensors to dynamically monitor the movement of the load, and controls the actuator to adjust the force according to the vibration of the load platform, thereby achieving low-frequency vibration attenuation. The characteristics of this technical solution are: 1) High-precision sensors and linear drives are required to achieve accurate monitoring and attenuation of load movement, which is costly. 2) An active negative stiffness structure composed of sensors, controllers and actuators is used, which has 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. The electromagnetic vibration isolation unit includes a permanent magnet and an electromagnetic coil arranged outside the permanent magnet. By changing the number of layers of the permanent magnet and the coil and adjusting the current, the magnetic field strength and magnetic induction line distribution generated by the electromagnetic coil are changed, thereby realizing an adjustable negative stiffness characteristic, offsetting the positive stiffness of the coil spring, making the system appear to be quasi-zero stiffness to the outside, and achieving optimal vibration isolation performance. The technical solution is characterized in that: (1) the electromagnetic vibration isolation unit is composed of a permanent magnet and an electromagnetic coil, and can only produce negative stiffness characteristics under continuous energy input, resulting in high system energy consumption; (2) the permanent magnets in the electromagnetic vibration isolation unit have the same magnetization direction, and only one side of the magnetic field is utilized, while the other side of the magnetic field is idle. The low utilization rate of the magnetic field leads to a limited negative stiffness value; when applied to a vibration isolation platform with a large load or high natural frequency, its stiffness control effect is very small, and it is impossible or difficult to achieve the needs of low-frequency, ultra-low-frequency or even near-zero-frequency vibration isolation.

[0005] Patent No. ZL202011189248.9 discloses a six-degree-of-freedom micro-vibration isolation device based on an active electromagnetic negative stiffness structure. The active electromagnetic negative stiffness structure uses coaxially nested double magnetic rings to achieve non-adjustable negative stiffness characteristics in the vertical direction, and uses a powered coil coaxially nested with the double magnetic rings to generate a precisely controllable excitation flux to adjust the bias magnetic field, thereby dynamically adjusting the negative stiffness value to adapt to changes in the mass of the vibration isolation load and the excitation frequency. The technical solution is characterized in that the bias magnetic field is provided by a fixed magnetic ring, and only a small current is required in the coil to generate an excitation flux to adjust the bias magnetic field without the need for continuous high energy input, and the system energy consumption is relatively low. The coaxially nested double magnetic rings adopt an axially unidirectional magnetization method to form a symmetrical excitation magnetic field on the inner and outer sides of the magnetic ring. However, only the magnetic field on the outside of the inner magnetic ring is effectively utilized, while the magnetic field on the inside is idle. This design reduces the utilization rate of the magnetic field, resulting in a lower negative stiffness value generated by the coaxial dual magnetic rings; when facing the vibration isolation requirements of large loads and high natural frequencies, its stiffness control effect is minimal, and it is impossible or difficult to achieve low-frequency, ultra-low-frequency or even near-zero-frequency vibration isolation effects.

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

[0007] The purpose of the present invention is to address the problem that the existing six-degree-of-freedom quasi-zero-stiffness vibration isolators with adjustable stiffness have high energy consumption and are difficult to generate sufficiently high negative stiffness to achieve low-frequency, ultra-low-frequency or even near-zero-frequency vibration isolation effects when facing the vibration isolation requirements of large loads and high natural frequencies. A six-degree-of-freedom low-frequency micro-vibration isolation device based on a vertically magnetized space electromagnetic array is proposed, which can not only achieve high-performance micro-vibration isolation in six degrees of freedom in space (translation along the x, y, and z axes and rotation around the x, y, and z axes), but also has high stability and strong adaptability. The negative stiffness structure of the vertically magnetized space electromagnetic array utilizes 2n+1 (n≥1, n∈N + ) layers are arranged in an axial array and the adjacent layers are coaxially nested with equal-section magnetic arrays that are perpendicularly magnetized, which enhances the excitation magnetic field on the working side, improves the magnetic field utilization rate, and reduces leakage magnetic flux; and uses the energized coils coaxially nested with the vertically magnetized spatial magnetic ring array to generate precisely controllable excitation flux, dynamically adjusting the negative stiffness to adapt to changes in the vibration isolation load mass and the excitation frequency.

[0008] The technical solution of the present invention is:

[0009] A six-degree-of-freedom low-frequency micro-vibration isolator based on a vertically magnetized space electromagnetic array comprises an upper plate, a base plate and six sets of low-frequency electromagnetic vibration isolators connected in a Stewart manner. The upper plate has three translational degrees of freedom and three rotational degrees of freedom relative to the base plate. The top of the low-frequency electromagnetic vibration isolator is connected to a fixing at the bottom of the upper plate through an upper flexible hinge, and the bottom is connected to a fixing at the top of the base plate through a lower flexible hinge. The axes of two adjacent low-frequency electromagnetic vibration isolators are perpendicular to each other. The low-frequency electromagnetic vibration isolator is composed of a vertically magnetized space electromagnetic array negative stiffness structure and a spiral spring in parallel. The vertically magnetized space electromagnetic array negative stiffness structure comprises a moving magnetic ring array, a moving magnetic array mounting part, a fixed magnetic ring array, a fixed magnetic array fixing part, a coil, an upper actuator and a lower connecting part. The moving magnetic array mounting part, the moving magnetic ring array, the fixed magnetic ring array, the fixed magnetic array fixing part and the coil are coaxially mounted and arranged in sequence from the axis along the radius outward, and the overall structure is axisymmetric. The moving magnetic array mounting part is an annular sleeve, and the top end is fixedly connected to the upper actuator through a thread. An annular boss is arranged at the bottom, and an annular groove is arranged inside the boss; the top of the spiral spring is coaxially fixedly installed in the annular groove at the bottom of the moving magnetic array mounting piece, and the bottom is coaxially nested and fixedly installed in the annular groove at the bottom of the fixed magnetic array mounting piece; the moving magnetic ring array is coaxially nested, tightly matched, and fixedly installed on the outer side of the moving magnetic array mounting piece, and a gap is arranged radially with the fixed magnetic ring array and the fixed magnetic array fixing piece; the fixed magnetic array fixing piece is an annular sleeve with deep grooves arranged along the circumference on both the inner and outer sides, and a certain gap is maintained axially between the top and the upper flexible hinge, and the bottom is fixedly connected to the lower connecting piece through a thread; the fixed magnetic ring array is coaxially nested, tightly matched, and fixedly installed in the deep groove on the inner side of the fixed magnetic array fixing piece, the coil is symmetrical about the axial height center of the fixed magnetic ring array, and is coaxially nested, tightly matched, and fixedly installed in the deep groove on the outer side of the fixed magnetic array fixing piece, and the current is adaptively feedback adjusted by the controller according to the vibration acceleration of each degree of freedom; the moving magnetic ring array and the fixed magnetic ring array are both composed of 2n+1(n≥1, n∈N + ) layers are arranged in an axial array and adjacent layers are magnetized perpendicularly to each other, wherein the heights of the odd-numbered layers of magnetic rings are equal, the heights of the even-numbered layers of magnetic rings are 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; the first layer of magnetic rings in the moving magnetic ring array and the fixed magnetic ring array are magnetized in opposite directions along the radial direction, and their bottom surfaces coincide; 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.

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

[0011] 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.

[0012] 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°.

[0013] The technical innovation and good effects of the present invention are:

[0014] (1) This technical solution adopts a multi-layer array of equal-section magnetic rings arranged in an axial array and magnetized vertically between adjacent layers, which is coaxially nested and connected in parallel with the energized coil to achieve an adjustable high negative stiffness characteristic, which can adapt to changes in load weight and excitation frequency, and achieve low-frequency, ultra-low-frequency and even near-zero-frequency vibration isolation effects under variable large loads. For vibration isolation platforms with heavy loads and high natural frequencies, the higher the negative stiffness required to achieve low-frequency vibration isolation; the present invention adopts a design of multi-layer equal-section magnetic rings arranged in an axial array and magnetized vertically between adjacent layers, which not only effectively reduces leakage magnetic flux, but also significantly enhances the magnetic field strength on the working side, thereby achieving high negative stiffness characteristics. In addition, a precisely controllable excitation magnetic flux is generated by a energized coil coaxially nested with the vertically magnetized magnetic ring array, thereby adjusting the bias magnetic field around the moving magnetic ring array, making the negative stiffness adjustable. Therefore, the present 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 with variable large loads, which is one of its important innovations that distinguish it from the prior art.

[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 cutting-edge instruments and equipment, and significantly improving the accuracy of the equipment. By using a low-frequency electromagnetic vibration isolator composed of six vertically magnetized spatial electromagnetic array negative stiffness structures in parallel with a coil spring, the local low dynamic stiffness characteristics of six degrees of freedom can be achieved without changing the bearing capacity of the coil spring, effectively reducing the natural frequency of the vibration isolation system and expanding the vibration isolation bandwidth, thereby isolating vibrations from the six degrees of freedom in space (translation along the x, y, z axes and rotation around the x, y, z axes), ensuring the normal operation of precision instruments and maintaining high precision. This is the second innovation that distinguishes the present invention from the prior art.

[0016] (3) The present invention has the advantages of compact structure, easy installation and low maintenance cost. This enables the device to be easily integrated into the existing instrument system, improving the overall performance and reliability of the system. At the same time, the lower maintenance cost also reduces the use cost and improves the economy of the device. This is the third innovative point that distinguishes the present invention from the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is 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 It is a three-dimensional cross-sectional schematic diagram of a low-frequency electromagnetic vibration isolator;

[0019] Figure 3 It is a front cross-sectional view of the low-frequency electromagnetic vibration isolator;

[0020] Figures 4 to 10 Schematic diagram of the relative position and magnetization direction 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] Explanation of the part numbers in the figure: 1 moving magnetic ring array, 2 moving magnetic array mounting part, 3 fixed magnetic ring array, 4 fixed magnetic array fixing part, 5 coil, 61 upper actuator, 62 lower connecting part, 7 spiral spring, 81 upper flexible hinge, 82 lower flexible hinge, 9 upper plate, 10 base plate, 11 vertical magnetization space electromagnetic array negative stiffness structure, 12 fixing part, 13 low-frequency electromagnetic vibration isolator. DETAILED DESCRIPTION

[0022] The specific implementation modes of the present invention are described in detail below with reference to the accompanying drawings.

[0023] A six-degree-of-freedom low-frequency micro-vibration isolator based on a vertically magnetized space electromagnetic array comprises an upper plate 9, a base plate 10 and six sets of low-frequency electromagnetic vibration isolators 13 connected to the upper plate 9 and arranged in a Stewart manner. 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 the low-frequency electromagnetic vibration isolator 13 is connected to the fixing part 12 at the bottom of the upper plate 9 through an upper flexible hinge 81, and the bottom is connected to the fixing part 12 at the top of the base plate 10 through a lower flexible hinge 82. The axes of two adjacent low-frequency electromagnetic vibration isolators 13 are perpendicular to each other. The device 13 is composed of a vertical magnetization space electromagnetic array negative stiffness structure 11 and a coil spring 7 in parallel; the vertical magnetization space electromagnetic array negative stiffness structure 11 includes a moving magnetic ring array 1, a moving magnetic array mounting part 2, a fixed magnetic ring array 3, a fixed magnetic array fixing part 4, a coil 5, an upper actuator 61 and a lower connecting part 62, the moving magnetic array mounting part 2, the moving magnetic ring array 1, the fixed magnetic ring array 3, the fixed magnetic array fixing part 4 and the coil 5 are coaxially installed and arranged in sequence from the axis along the radius outward, and the overall structure is axisymmetric; the moving magnetic array mounting part 2 is an annular sleeve, and the top is connected by a spiral spring. The groove is fixedly connected to the upper actuator 61, an annular boss is arranged at the bottom, and an annular groove is arranged in the boss; the top of the coil spring 7 is coaxially fixedly installed in the annular groove at the bottom of the dynamic magnetic array mounting member 2, and the bottom is coaxially nested and fixedly installed in the annular groove at the bottom of the fixed magnetic array fixing member 4; the dynamic magnetic ring array 1 is coaxially nested, tightly matched, and fixedly installed on the outer side of the dynamic magnetic array mounting member 2, and a gap is provided radially with the fixed magnetic ring array 3 and the fixed magnetic array fixing member 4; the fixed magnetic array fixing member 4 is an annular sleeve with deep grooves on both the inner and outer sides along the circumference, and the top is fixed to the upper The flexible hinge 81 maintains a certain gap in the axial direction, and its bottom is fixedly connected to the lower connecting piece 62 through a thread; the fixed magnetic ring array 3 is coaxially nested, tightly matched, and fixedly installed in the deep groove on the inner side of the fixed magnetic array fixing piece 4, and the coil 5 is symmetrical about the axial height center of the fixed magnetic ring array 3, and is coaxially nested, tightly matched, and fixedly installed in the deep groove on the outer side of the fixed magnetic array fixing piece 4, and its power-on current is adaptively feedback-adjusted by the controller according to the vibration acceleration of each degree of freedom; the dynamic magnetic ring array 1 and the fixed magnetic ring array 3 are both composed of 2n+1 (n≥1, n∈N + ) layers are arranged in an axial array and adjacent layers are magnetized perpendicularly to each other, wherein the heights of the odd-numbered layers of magnetic rings are equal, the heights of the even-numbered layers of magnetic rings are equal, and 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 first layer of magnetic rings in the moving magnetic ring array 1 and the fixed magnetic ring array 3 are magnetized in opposite directions in the radial direction, and their bottom surfaces coincide; 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.

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

[0025] As a specific implementation, the precisely controllable driving current in the coil 5 is generated by a linear regulator, a linear driver, a switching regulator or a switching driver.

[0026] As a specific implementation method, the radially magnetized magnetic rings in the moving magnetic ring array 1 and the fixed magnetic ring array 3 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°.

[0027] Combine the following Figure 1 to Figure 3 An embodiment of the present invention is given.

[0028] like Figure 1 As shown, the present invention comprises an upper plate 9, a base plate 10 and six sets of low-frequency electromagnetic vibration isolators 13 connected to the upper plate 9 and arranged in a Stewart manner. 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 around 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, and the bottom of the lower connecting member 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 set of low-frequency electromagnetic vibration isolators 13 is composed of a vertically magnetized space electromagnetic array negative stiffness structure 11 and a coil spring 7 in parallel; the vertically magnetized space electromagnetic array negative stiffness structure 11 includes a moving magnetic ring array 1, a moving magnetic array mounting member 2, a fixed magnetic ring array 3, a fixed magnetic array fixing member 4, a coil 5, an upper actuator 61 and a lower connecting member 62, the moving magnetic array mounting member 2, the moving magnetic ring array 1, the fixed magnetic ring array 3, the fixed magnetic array fixing member 4 and the coil 5 are coaxially installed, and are arranged in sequence from the axis along the radius outward, and the overall structure is axially symmetrical; the moving magnetic array mounting member 2 is an annular sleeve, and the material is 7075 aluminum alloy, and its top is fixedly connected to the upper actuator 61 through four threaded holes evenly distributed along the circumference, and an annular boss is arranged at the bottom, and an annular groove is arranged in the boss; the positive stiffness characteristics of the coil spring 7 are used to achieve stable support of the vibration isolation load, and its top It is coaxially fixedly installed in the annular groove at the bottom of the moving magnetic array mounting part 2, and the bottom 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, and a gap of 5mm to 20mm is provided radially with 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 provided along the circumference on both the inner and outer sides, and a certain gap is maintained axially between the top and the upper flexible hinge 81, and the bottom is fixedly connected to the lower connecting part 62 by a thread; the fixed magnetic ring array 3 is coaxially nested, tightly fitted, and fixedly installed in the deep groove on the inner side of the fixed magnetic array fixing part 4, and 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 on the outer side of the fixed magnetic array fixing part 4.

[0030] The moving magnetic ring array 1 and the fixed magnetic ring array 3 are both composed of 2n+1 (n≥1, n∈N +) layers are arranged in an axial array and adjacent layers are magnetized perpendicularly to each other. The material of the magnetic rings is N50 grade neodymium iron boron, with a residual magnetic induction intensity of 1.43T and a relative magnetic permeability of 1.03. The inner radius and outer radius of the moving magnetic ring array 1 are 1.3mm and 6.4mm respectively, the height of the moving magnetic rings of the odd-numbered layers is 2mm, and the height of the moving magnetic rings of the even-numbered layers is 3.4mm. The inner radius and outer radius of the fixed magnetic ring array 3 are 7mm and 10mm respectively, the height of the fixed magnetic rings of the odd-numbered layers is 2mm, and the height of the fixed magnetic rings of the even-numbered layers is 3.4mm. The first layer of the moving magnetic ring array 1 is magnetized along the radius to the axis, and the first layer of the fixed magnetic ring array 3 is magnetized from the axis along the radius to the outside, and their bottom surfaces overlap; on the right half of the front section 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. 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 vertical magnetization space electromagnetic array can be maximized; compared with the negative stiffness structure composed of coaxial nesting of radially oppositely magnetized magnetic rings, the negative stiffness value can be increased by 155 times under the same size condition; compared with the negative stiffness structure composed of coaxial nesting of axially same-direction magnetized magnetic rings, the negative stiffness value can be increased by 21.4 times under the same size condition.

[0031] The coil 5 is formed by winding an insulated copper enameled wire, and has a circular cross section. The coil 5 is symmetrical about the axial height center of the fixed magnetic ring array 3. A precisely controllable driving current generated by a linear regulator, a linear driver, a switching regulator or a switching driver is passed through the coil 5, and the maximum current density is 5A / mm 2 . When the vertical magnetization space electromagnetic array negative stiffness structure 11 is working, the control signal is amplified by the power amplifier, and the output drive current is loaded into the coil 5. According to the law of electromagnetic induction, a precisely controllable excitation flux is generated around the energized coil 5, and the excitation flux is superimposed with the bias magnetic field generated by the fixed magnetic ring array 3 around the moving magnetic ring array 1 to form a magnetic field that realizes the negative stiffness characteristic. When a counterclockwise current is passed through the coil 5, the excitation flux and the bias magnetic field have the same direction of magnetic force on the moving magnetic ring array 1, and both cause the moving magnetic ring array 1 to deviate from the static equilibrium position under external excitation interference, and 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 a state of equilibrium. Under the excitation of axial micro-disturbance, the moving magnetic ring array 1 will move relative to the fixed magnetic ring array 3. At this time, the axial equilibrium state of the moving magnetic ring array 1 is broken, while the radial direction is still balanced. The axial magnetic force of the fixed magnetic ring array 3 acting 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 balance cannot be restored. That is, the axial magnetic force of the negative stiffness structure 11 of the vertical magnetization space electromagnetic array presents a negative stiffness characteristic. When it is connected in parallel with the coil spring 7 to support the vibration isolation load, its vibration isolation bandwidth can be regulated by only generating a negative stiffness characteristic without affecting the load-bearing capacity of the coil spring 7.

[0033] The dynamic magnetic ring array 1, the fixed magnetic ring array 3 and the energized coil 5 cooperate to produce an adjustable high negative stiffness characteristic, so that the six-degree-of-freedom low-frequency micro-vibration isolation device can be adaptively adjusted according to the actual working conditions, thereby achieving low-frequency, ultra-low-frequency and even near-zero-frequency vibration isolation effects. When the load mass or the excitation frequency changes, the controller adaptively feedbacks and adjusts the magnitude and direction of the energized current in the coil 5 according to the vibration acceleration of each degree of freedom, which can precisely control the magnitude and direction of the excitation flux, and can change the magnitude and direction of the magnetic force on the dynamic magnetic ring array 1, so as to adjust the negative stiffness value, and thus adapt to the changes in the vibration isolation load mass and the excitation frequency. Specifically, when the load mass increases, the controller adaptively increases the energized current in the coil 5 according to the vibration acceleration of each degree of freedom, so as to enhance the repulsive force of the vertical magnetization space electromagnetic array negative stiffness structure 11, so that it provides a greater negative stiffness to balance the increased load mass, thereby ensuring that the vibration isolation system can still achieve a near full-frequency vibration isolation bandwidth under a larger load mass. In addition, when the excitation frequency is reduced to a level close to or lower than the natural frequency of the precision micro-vibration isolation system, the controller adaptively feedback-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 vertically magnetized space electromagnetic array, thereby effectively reducing the natural frequency of the vibration isolation, avoiding the resonance area, 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 the magnetic ring is complicated and the magnetization effect cannot be guaranteed. Therefore, it is usually made by splicing multiple tile-shaped magnets that are uniformly magnetized in the radial direction. Figures 4 to 10 Schematic diagram of the relative position and magnetization direction 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 respectively spliced ​​to form a radial magnetization 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 micro-vibration isolator based on a vertically magnetized space electromagnetic array, comprising an upper plate (9), a base plate (10) and six sets of low-frequency electromagnetic vibration isolators (13) connected to the upper plate (9) and arranged in a Stewart manner, wherein 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 the low-frequency electromagnetic vibration isolator (13) is connected to a fixing member (12) at the bottom of the upper plate (9) through an upper flexible hinge (81), and the bottom thereof is connected to a fixing member (12) at the top of the base plate (10) through a lower flexible hinge (82), and the axes of two adjacent low-frequency electromagnetic vibration isolators (13) are perpendicular to each other; characterized in that: The low-frequency electromagnetic vibration isolator (13) is composed of a vertical magnetization space electromagnetic array negative stiffness structure (11) and a coil spring (7) in parallel; the vertical magnetization space electromagnetic array negative stiffness structure (11) comprises a moving magnetic ring array (1), a moving magnetic array mounting member (2), a fixed magnetic ring array (3), a fixed magnetic array fixing member (4), a coil (5), an upper actuator (61) and a lower connecting member (62); the moving magnetic array mounting member (2), the moving magnetic ring array (1), the fixed magnetic ring array (3), the fixed magnetic array fixing member (4) and the coil (5) are coaxially mounted and arranged in sequence from the axis along the radius outward, and the overall structure The structure is axially symmetrical; the moving magnetic array mounting member (2) is an annular sleeve, the top end of which is fixedly connected to the upper actuator (61) through a thread, and the bottom end is provided with an annular boss, and an annular groove is provided in the boss; the top end of the spiral spring (7) is coaxially fixedly mounted in the annular groove at the bottom end of the moving magnetic array mounting member (2), and the bottom end is coaxially nested and fixedly mounted in the annular groove at the bottom end of the fixed magnetic array fixing member (4); the moving magnetic ring array (1) is coaxially nested, tightly matched, and fixedly mounted on the outer side surface of the moving magnetic array mounting member (2), and a gap is provided in the radial direction with the fixed magnetic ring array (3) and the fixed magnetic array fixing member (4); the fixed magnetic array fixing member (4) is fixedly mounted on the outer side surface of the moving magnetic array mounting member (2); The fixed member (4) is an annular sleeve with deep grooves formed along the circumference on both the inner and outer sides, the top end of which maintains a certain gap with the upper flexible hinge (81) in the axial direction, and the bottom end of which is fixedly connected to the lower connecting member (62) through a thread; the fixed magnetic ring array (3) is coaxially nested, tightly fitted, and fixedly installed in the deep groove on the inner side of the fixed magnetic array fixing member (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 on the outer side of the fixed magnetic array fixing member (4); the current passing through the coil is adaptively feedback-regulated by a controller according to the vibration acceleration of each degree of freedom. The invention discloses a method for manufacturing a magnetic ring array for a moving magnetic ring. The invention discloses a method for manufacturing a moving magnetic ring array for a moving magnetic ring array. The moving magnetic ring array (1) and the fixed magnetic ring array (3) are both composed of 2n+1 (n≥1) layers of magnetic rings of equal cross-section arranged in an axial array and magnetized perpendicularly between adjacent layers, wherein the heights of the magnetic rings of odd-numbered layers are equal, the heights of the magnetic rings of even-numbered layers are equal, and the heights of the magnetic rings of the same layer in the moving magnetic ring array (1) and the fixed magnetic ring array (3) are equal; the first layers of magnetic rings of the moving magnetic ring array (1) and the fixed magnetic ring array (3) are magnetized in opposite directions in the radial direction, and their bottom surfaces overlap; 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.

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

3. The six-degree-of-freedom low-frequency isolation micro-vibrator based on a vertically magnetized spatial electromagnetic array according to claim 1, characterized in that: The precisely controllable driving 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 isolation micro-vibrator 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 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°.

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