A six-degree-of-freedom two-stage isolating microvibrator based on integrated control of negative stiffness damping.

Abstract

The six-degree-of-freedom two-stage vibration isolation micro-vibration device based on integrated negative stiffness damping control belongs to the field of precision vibration isolation technology. It utilizes twelve sets of low-frequency vibration isolation dampers arranged in a Stewart pattern, connecting the upper plate and the base plate, to achieve near-full-band vibration isolation performance under variable loads. The low-frequency vibration isolation damper consists of a negative stiffness damping integrated controller and a helical spring connected in parallel to support the load platform. The negative stiffness damping integrated controller utilizes a multi-layered, axially arranged array of uniform-section magnetic rings with perpendicular magnetization between adjacent layers to construct a single-sided high magnetic density excitation magnetic field, effectively weakening the magnetic field strength on the non-working side. Furthermore, the vertically magnetized fixed magnetic ring array and the moving magnetic ring array are coaxially nested to achieve high negative stiffness characteristics, and coaxially nested with the coil to achieve high damping characteristics. Adjusting the coil current can generate localized low dynamic stiffness and adjustable high damping characteristics under high load conditions, precisely matching the stiffness and damping parameters to achieve near-full-band high-performance vibration isolation in multiple degrees of freedom.

Description

Technical Field

[0001] This invention belongs to the field of precision vibration isolation technology, specifically a six-degree-of-freedom two-stage vibration isolation micro-vibrator based on integrated control of negative stiffness damping. Background Technology

[0002] Low-frequency micro-amplitude vibrations have become a key factor restricting the improvement of accuracy in the assembly, testing, and experimentation of precision instruments and equipment. To address this issue, configuring low-frequency vibration isolation platforms for precision equipment has become a crucial technical approach in the field of ultra-precision engineering. The core performance of a vibration isolation platform lies in its stiffness and damping, two parameters that directly affect its suppression effect on vibrations of various frequencies. Specifically, a vibration isolation platform exhibits "low-pass filtering" characteristics. Its stiffness determines the initial isolation frequency and isolation bandwidth; lower stiffness results in a lower initial isolation frequency and a wider isolation bandwidth. Damping characteristics, on the other hand, determine the platform's vibration attenuation efficiency. Low damping is beneficial for attenuating high-frequency vibrations, while high damping helps reduce the platform's transmission rate of low-frequency vibrations. Therefore, precise control of these two parameters is key to improving the overall performance of the vibration isolation platform and achieving high-precision vibration suppression.

[0003] Currently, research on control technologies mainly focuses on single-degree-of-freedom vibration isolation systems, emphasizing the adjustment of either stiffness or damping. However, research on six-degree-of-freedom systems, which are more suited to practical applications and can comprehensively and efficiently attenuate vibration interference from complex and variable spatial environments, is relatively scarce. Furthermore, adjusting stiffness or damping individually easily reaches performance bottlenecks, making it difficult to simultaneously optimize both vibration isolation effect and isolation bandwidth. How to achieve coordinated and integrated control of vibration isolation stiffness and damping in six degrees of freedom to broaden the isolation bandwidth and improve vibration attenuation efficiency has become a major challenge restricting breakthroughs in comprehensive, full-bandwidth high-performance vibration isolation technology and meeting the demands of high-precision applications.

[0004] Patent No. 201910634275.3 discloses a quasi-zero stiffness vibration isolation and energy harvesting system based on the Stewart platform. This technical solution utilizes a ring permanent magnet and electromagnets arranged in a vertical array to provide semi-active negative stiffness, which counteracts the positive stiffness of the diaphragm spring. The introduction of electromagnets makes the negative stiffness adjustable, adapting to changes in the vibration isolation load mass and excitation frequency, increasing the vibration isolation frequency band, and achieving a lower frequency vibration isolation effect. The features of this technical solution are: (1) The uniform magnetization of the ring permanent magnet results in the excitation magnetic field generated being utilized only near the electromagnet side, with low magnetic field utilization and limited negative stiffness value, which is not effective for the stiffness of heavy-load or high-frequency vibration isolation systems; (2) It only has stiffness adjustment function, but cannot adjust the vibration damping, which limits the improvement of vibration attenuation rate and makes it difficult to achieve high-performance attenuation of full-frequency vibration; (3) The vibration attenuation rate can only reach 20dB / dec.

[0005] Patents CN202011189248.9, CN201610915703.6, CN201610834355.X, CN201510395953.7, CN201810300899.7, CN201811101215.7 and CN202311199383.5 all disclose six-degree-of-freedom vibration isolators. The features of the above technical solutions are: (1) For a magnetic ring that is uniformly magnetized along the radial or axial direction, the excitation magnetic field generated is only utilized on one side, the magnetic field utilization rate is low, the generated negative stiffness value is limited, and the effect on the stiffness of heavy-load or high-frequency vibration isolation systems is not good; (2) It only has stiffness adjustment function, but cannot adjust vibration damping, which limits the improvement of vibration attenuation rate and makes it difficult to achieve high-performance attenuation of full-frequency vibration; (3) It can only attenuate vibration interference once, and the vibration attenuation rate can only reach 20dB / dec.

[0006] Patent CN202211463942.4 discloses a multi-degree-of-freedom variable stiffness and variable damping vibration isolator composed of an air spring and six sets of magnetorheological dampers. The stiffness is adjusted by changing the amount of gas in the air chamber through the air hole, and the damping force of each set of magnetorheological dampers is changed by adjusting the input current of the coil. The technical solution is characterized by: (1) Due to the limitation of structural and material stiffness, the natural frequency of the air spring cannot be reduced to zero by adjusting the amount of gas in the air chamber, so it is difficult to achieve low-frequency or even near-zero frequency vibration isolation; (2) The properties of magnetorheological fluid are unstable and easily affected by external environmental factors such as temperature and humidity. Under high temperature or low temperature environment, its damping performance may change, and it may even fail to work properly; (3) Long-term use or improper use may cause slag to be generated inside the magnetorheological damper, affecting the damping effect and service life; (4) The vibration attenuation rate can only reach 20dB / dec.

[0007] In summary, the key challenge lies in developing a vibration isolation micro-vibration device that can adaptively and collaboratively adjust the vibration isolation stiffness and damping, and can perform multi-level, multi-freedom attenuation of vibration interference through innovative vibration isolation structures and principles. This device should be able to dynamically adjust the vibration isolation stiffness and damping based on real-time sensing of load mass changes and fluctuations in the external six-degree-of-freedom excitation frequency, precisely matching the stiffness and damping parameters to achieve all-round, near-full-band, and high-performance vibration isolation. This would isolate the impact of environmental micro-vibrations on precision instruments and equipment, creating a more stable and reliable environment for high-precision assembly, testing, and experimental work. This is of strategic significance for promoting technological progress and accelerating industrial upgrading. Summary of the Invention

[0008] The purpose of this invention is to address the problem that existing six-degree-of-freedom vibration isolators cannot simultaneously achieve adaptive control of stiffness and damping, making it difficult to achieve comprehensive, near-full-band, and efficient isolation of environmental micro-vibration interference. This invention proposes a six-degree-of-freedom two-stage micro-vibration isolator based on integrated control of negative stiffness and damping. It employs twelve sets of low-frequency vibration dampers arranged in a Stewart configuration, connected to the upper and lower plates, to achieve multi-degree-of-freedom near-full-band vibration isolation. These dampers are supported by a negative stiffness damping controller and helical springs in parallel. A multi-layered vertically magnetized magnetic ring array constructs a high magnetic flux density magnetic field on one side, weakening the magnetic field on the non-working side. The fixed and moving magnetic ring arrays, along with the coaxial nesting of coils, achieve high negative stiffness and eddy current damping. A control algorithm based on acceleration and velocity composite feedback is used to regulate the coil current, enabling low dynamic stiffness and low-frequency high-damping, high-frequency low-damping characteristics under heavy loads. This precisely matches the multi-degree-of-freedom vibration isolation requirements, adapts to load and frequency changes, and significantly improves the vibration attenuation rate.

[0009] The technical solution of this invention is:

[0010] A six-degree-of-freedom two-stage vibration isolator based on integrated negative stiffness damping control includes an upper plate, a middle plate, a base plate, and twelve sets of low-frequency vibration isolation dampers arranged in a Stewart configuration connecting the three. The upper plate has three translational degrees of freedom relative to the middle plate, and the middle plate has three rotational degrees of freedom relative to the base plate. The tops of six sets of low-frequency vibration isolation dampers are connected to the bottom of the upper plate via upper flexible hinges, and their bottoms are connected to the top of the middle plate via lower flexible hinges. The tops of the other six sets of low-frequency vibration isolation dampers are connected via upper flexible hinges. It is connected to the fixing part at the bottom of the middle plate, and its bottom is connected to the fixing part at the top of the base plate through the lower flexible hinge. The axes of two adjacent low-frequency vibration damping devices are perpendicular to each other. The low-frequency vibration damping device is composed of a helical spring and a negative stiffness damping integrated controller connected in parallel. The negative stiffness damping integrated controller includes a fixed magnetic ring array, a fixed magnetic ring fixing part, a moving magnetic ring array, a moving magnetic ring connecting part, a coil, a coil frame, a sensor, a signal conditioner, a data acquisition instrument, a controller, a driver, an upper connecting part and a lower connecting part, a fixed magnetic ring fixing part, a fixed ... frame, a sensor, a signal conditioner, a data acquisition instrument, a controller, a driver, an upper connecting part and a lower connecting part, a fixed magnetic ring fixing part, a fixed magnetic ring array, a moving magnetic ring connecting part, a coil frame The magnetic ring connector, moving magnetic ring array, coil frame, and coil are coaxially nested and arranged outwards from the axis, forming an axially symmetrical overall structure. The fixed magnetic ring fixing component is a cylindrical structure with an inverted T-shaped cross-section. Its bottom is fixedly connected to the coil frame by threads, while its top maintains a certain gap with the moving magnetic ring connector. The fixed magnetic ring array is coaxially nested, tightly fitted, and fixedly installed on the outer side of the fixed magnetic ring fixing component, with gaps in both the radial and axial directions between it and the moving magnetic ring connector. The moving magnetic ring connector is an annular sleeve, with its top fixed to the upper connector by threads. The connection features an annular boss at the bottom with an annular groove inside. A helical spring is coaxially nested with the moving magnetic ring connector and the coil frame, its top fixedly installed in the annular groove at the bottom of the moving magnetic ring connector, and its bottom fixedly installed in the annular groove on the bottom surface of the coil frame. The moving magnetic ring array is coaxially nested, tightly fitted, and fixedly installed on the outer side of the moving magnetic ring connector, with a radial gap between it and the coil frame. Both the fixed magnetic ring array and the moving magnetic ring array consist of multiple layers of uniform cross-section magnetic rings arranged axially and perpendicularly magnetized between adjacent layers, with two layers in each array. n +1, where, n ≥1, n∈N +The odd-numbered magnetic ring layers have equal heights, and the even-numbered magnetic ring layers have equal heights. The first layer of the fixed magnetic ring array and the moving magnetic ring array are magnetized in opposite radial directions. On the right half of the front sectional view, with each additional layer, the magnetization direction of the fixed magnetic ring rotates 90° clockwise, and the magnetization direction of the moving magnetic ring rotates 90° counterclockwise. The coil frame is an annular sleeve with deep grooves along its circumference on its outer side. Its top maintains a certain gap with the upper flexible hinge, and its bottom is fixedly connected to the lower connector by threads. The coil is coaxially nested, tightly fitted, and fixedly installed on the outer side of the coil frame. The coil is connected to the output terminal of the driver, and the input terminal of the driver is connected via a serial port or network. The system is connected to the output of a controller, which integrates a control algorithm based on a composite feedback of acceleration and velocity. Its input reads information from a data acquisition unit via a serial port or network. The input of the data acquisition unit is connected to the output of a signal conditioner, and the input of the signal conditioner is connected to a sensor. The sensor captures changes in load mass or fluctuations in the external excitation frequency and feeds this information back to the controller. The controller employs a control algorithm based on a composite feedback of acceleration and velocity to adjust the current flowing through the coil, thereby controlling the vibration isolation stiffness and damping parameters, producing high damping characteristics for low-frequency vibrations and low damping characteristics for high-frequency vibrations.

[0011] The driver's input is connected to the data acquisition unit's output, the data acquisition unit's input is connected to the signal conditioner's output, the signal conditioner's input is connected to the sensor, and the data acquisition unit is connected to the controller via a serial port or network.

[0012] Preferably, the heights of the fixed magnetic ring array and the moving magnetic ring array in the same layer are equal.

[0013] Preferably, the bottom surface of the first layer of magnetic rings in the fixed magnetic ring array coincides with the bottom surface of the first layer of magnetic rings in the moving magnetic ring array.

[0014] Preferably, the height of the coil is equal to the height of the fixed magnetic ring array, and is symmetrical about the axial height of the fixed magnetic ring array.

[0015] Preferably, the driver is a linear regulator, a linear driver, a switching regulator, or a switching driver.

[0016] Preferably, the radially magnetized magnetic rings in the fixed magnetic ring array and the moving magnetic ring array are composed of multiple radially uniformly magnetized tile-shaped magnets spliced ​​together. The number of tile-shaped magnets is 4, 5, 6, 8, 10, 12 or 15, and the gap between adjacent tile-shaped magnets does not exceed 3°.

[0017] Preferably, the sensor is a single six-degree-of-freedom velocity sensor or acceleration sensor, or a sensor group consisting of velocity sensors or acceleration sensors with three translational degrees of freedom and three rotational degrees of freedom.

[0018] Preferably, the signal conditioner includes an amplifier and a filter, wherein the gain and bandwidth of the amplifier are adjustable, the filter can perform high-pass filtering, and its cutoff frequency is adjustable.

[0019] Preferably, the materials of the fixed magnetic ring fixing component, the moving magnetic ring connecting component, the upper connecting component, the lower connecting component, the upper flexible hinge, the lower flexible hinge, and the helical spring are non-magnetic or weakly magnetic aluminum alloy, titanium alloy, or austenitic stainless steel.

[0020] Preferably, the material of the coil frame is ceramic, granite, fiberglass, or rigid plastic.

[0021] The technical innovation and positive effects of this invention are as follows:

[0022] (1) This technical solution utilizes a vertically magnetized fixed magnetic ring array and a moving magnetic ring array coaxially nested to achieve high negative stiffness characteristics, and a coaxially nested coil to achieve adjustable high damping characteristics. It boasts high magnetic field utilization and low system energy consumption. The low-frequency vibration isolation damper utilizes 2 n A single-sided high magnetic density excitation magnetic field is constructed by an array of uniform cross-section magnetic rings arranged axially along the +1 layer and perpendicularly magnetized between adjacent layers. n ≥1, n∈N + Furthermore, by coaxially nesting a vertically magnetized fixed magnetic ring array with a moving magnetic ring array and coils, high negative stiffness and adjustable high damping characteristics are achieved. The unilateral high magnetic density excitation magnetic field not only effectively weakens the magnetic field strength on the non-working side but also significantly enhances the magnetic field strength on the working side, thereby improving the negative stiffness and damping value of the low-frequency vibration isolation damper and expanding the vibration isolation frequency band and damping adjustment range. This is one of the innovative points that distinguishes this invention from existing technologies.

[0023] (2) This technical solution can sense the fluctuations in load mass and external excitation frequency in real time, and adjust the vibration isolation stiffness and damping accordingly to achieve precise coordination between the two, realizing near-full-band and high-performance vibration isolation in six degrees of freedom. The low-frequency vibration isolation damper utilizes a vertically magnetized fixed magnetic ring array and a moving magnetic ring array, with coils coaxially nested to achieve high negative stiffness and eddy current damping characteristics. When the load mass changes or the external excitation frequency fluctuates, the sensor captures these dynamic changes in real time and feeds the information back to the controller. The controller adopts a control algorithm based on acceleration and velocity composite feedback to adjust the current in the coil, precisely control the vibration isolation stiffness and damping parameters, and ensure high damping for low-frequency vibrations and low damping for high-frequency vibrations. When the low-frequency vibration isolation damper is connected in parallel with the helical spring to support the load platform, the vibration isolation frequency can be reduced to near zero frequency, and the vibration attenuation rate can be greatly improved, thereby achieving the optimal state of near-full-band high-performance vibration isolation in multiple degrees of freedom. This is the second innovative point of this invention that distinguishes it from the prior art.

[0024] (3) This invention employs a double-layer vibration isolation structure, which can efficiently attenuate vibration interference from three translational degrees of freedom and three rotational degrees of freedom. The double-layer vibration isolation structure is constructed using twelve sets of low-frequency vibration dampers arranged in a Stewart manner connecting the upper plate and the base plate, increasing the vibration attenuation rate from 20dB / Dec to 40dB / Dec. Faced with the same vibration interference, this double-layer vibration isolation structure can more efficiently reduce the transmission and amplification of vibration, thereby ensuring higher system stability and reliability. The double-layer vibration isolation system is significantly better than the single-layer vibration isolation system in mid-to-high frequency vibration isolation, and still achieves a considerable vibration isolation effect even when the overall mass ratio is less than the total mass ratio. Furthermore, by optimizing structural parameters such as damping ratio, mass ratio, and stiffness ratio, a better low-frequency vibration isolation effect than the equivalent linear vibration isolation system can be achieved. This is the third innovative point that distinguishes this invention from the prior art. Attached Figure Description

[0025] Figure 1 A three-dimensional model of a six-degree-of-freedom two-stage isolating microvibrator based on integrated control of negative stiffness damping;

[0026] Figure 2 A schematic diagram showing the arrangement of twelve sets of low-frequency vibration isolation dampers;

[0027] Figure 3 A three-dimensional cross-sectional schematic diagram of a low-frequency vibration isolation damper;

[0028] Figure 4 This is a front cross-sectional view of a low-frequency vibration isolation damper.

[0029] Part numbers in the diagram: 1. Base plate; 2. Fixed magnetic ring array; 3. Fixed magnetic ring fixture; 4. Moving magnetic ring array; 5. Moving magnetic ring connector; 6. Coil; 7. Coil frame; 8. Upper plate; 9. Sensor; 10. Signal conditioner; 11. Acquisition device; 12. Controller; 13. Driver; 14. Negative stiffness damping integrated controller; 15. Helical spring; 161. Upper connector; 162. Lower connector; 171. Upper flexible hinge; 172. Lower flexible hinge; 18. Fixture; 19. Low-frequency vibration damper; 20. Middle plate. Detailed Implementation

[0030] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0031] A six-degree-of-freedom two-stage vibration isolator based on integrated negative stiffness damping control includes an upper plate 8, a middle plate 20, a base plate 1, and twelve sets of low-frequency vibration isolation dampers 19 connected to the three in a Stewart arrangement. The upper plate 8 has three translational degrees of freedom relative to the middle plate 20, and the middle plate 20 has three rotational degrees of freedom relative to the base plate 1. The tops of six sets of low-frequency vibration isolation dampers 19 are connected to the bottom fixing members 18 of the upper plate 8 via upper flexible hinges 171, and their bottoms are connected to the top fixing members 18 of the middle plate 1 via lower flexible hinges 172. The tops of the other six sets of low-frequency vibration isolation dampers 19 are connected to the top fixing members 18 of the middle plate 1 via upper flexible hinges 172. The hinge 171 is connected to the fixing member 18 at the bottom of the middle plate 20, and its bottom is connected to the fixing member 18 at the top of the base plate 1 through the lower flexible hinge 172. The axes of two adjacent low-frequency vibration dampers 19 are perpendicular to each other. The low-frequency vibration damper 19 is composed of a helical spring 15 and a negative stiffness damping integrated controller 14 connected in parallel. The negative stiffness damping integrated controller 14 includes a fixed magnetic ring array 2, a fixed magnetic ring fixing member 3, a moving magnetic ring array 4, a moving magnetic ring connecting member 5, a coil 6, a coil frame 7, a sensor 9, a signal conditioner 10, a data acquisition unit 11, a controller 12, a driver 13, and an upper connecting member 161. The lower connector 162, the fixed magnetic ring fixing component 3, the fixed magnetic ring array 2, the moving magnetic ring connecting component 5, the moving magnetic ring array 4, the coil frame 7, and the coil 6 are coaxially nested and arranged outward from the axis along the radius, with the overall structure being axially symmetrical; the fixed magnetic ring fixing component 3 is a cylindrical structure with an inverted T-shaped cross-section, its bottom is fixedly connected to the coil frame 7 by threads, and its top maintains a certain gap with the moving magnetic ring connecting component 5; the fixed magnetic ring array 2 is coaxially nested, tightly fitted, and fixedly installed on the outer side of the fixed magnetic ring fixing component 3, and has gaps with the moving magnetic ring connecting component 5 in both the radial and axial directions; the moving magnetic ring connecting component 5 is an annular sleeve, its top end The coil spring 15 is fixedly connected to the upper connector 161 by threads, and an annular boss is provided at the bottom with an annular groove inside the boss. The coil spring 15 is coaxially nested with the moving magnetic ring connector 5 and the coil frame 7. Its top end is fixedly installed in the annular groove at the bottom of the moving magnetic ring connector 5, and its bottom end is fixedly installed in the annular groove at the bottom of the coil frame 7. The moving magnetic ring array 4 is coaxially nested, tightly fitted, and fixedly installed on the outer side of the moving magnetic ring connector 5, with a radial gap between it and the coil frame 7. Both the fixed magnetic ring array 2 and the moving magnetic ring array 4 are composed of multiple layers of uniform cross-section magnetic rings arranged in an axial array and perpendicularly magnetized between adjacent layers, with two layers in each case. n +1, where, n ≥1, n∈N +The odd-numbered layers of magnetic rings have equal heights, and the even-numbered layers have equal heights. The first layers of the fixed magnetic ring array 2 and the moving magnetic ring array 4 are magnetized in opposite directions radially. On the right half of the front sectional view, with each additional layer, the magnetization direction of the fixed magnetic ring rotates 90° clockwise, and the magnetization direction of the moving magnetic ring rotates 90° counterclockwise. The coil frame 7 is an annular sleeve with deep grooves along its outer circumference. Its top maintains a certain gap with the upper flexible hinge 171, and its bottom is fixedly connected to the lower connector 162 by threads. The coil 6 is coaxially nested, tightly fitted, and fixedly installed on the outer side of the coil frame 7. The coil 6 is connected to the output end of the driver 13, driving... The input terminal of the device 13 is connected to the output terminal of the data acquisition unit 11. The input terminal of the data acquisition unit 11 is connected to the output terminal of the signal conditioner 10. The input terminal of the signal conditioner 10 is connected to the sensor 9. The data acquisition unit 11 is connected to the controller 12 via a serial port or network. The sensor 9 captures changes in load mass or fluctuations in external excitation frequency and feeds the information back to the controller 12. The controller 12 uses a control algorithm based on acceleration and velocity composite feedback to adjust the current flowing in the coil 6, regulate the vibration isolation stiffness and damping parameters, and generate high damping characteristics for low-frequency vibration and low damping characteristics for high-frequency vibration.

[0032] In one specific implementation, the heights of the magnetic rings in the same layer of the fixed magnetic ring array 2 and the moving magnetic ring array 4 are equal.

[0033] In one specific implementation, the bottom surface of the first layer of magnetic rings in the fixed magnetic ring array 2 coincides with the bottom surface of the first layer of magnetic rings in the moving magnetic ring array 4.

[0034] In one specific implementation, the height of coil 6 is equal to the height of the fixed magnetic ring array 2, and is symmetrical about the axial height of the fixed magnetic ring array 2.

[0035] In one specific implementation, the driver 13 is a linear regulator, a linear driver, a switching regulator, or a switching driver.

[0036] In one specific implementation, the radially magnetized magnetic rings in the fixed magnetic ring array 2 and the moving magnetic ring array 4 are composed of multiple radially uniformly magnetized tile-shaped magnets spliced ​​together. The number of tile-shaped magnets is 4, 5, 6, 8, 10, 12 or 15, and the gap between adjacent tile-shaped magnets does not exceed 3°.

[0037] In one specific implementation, sensor 9 is a single six-degree-of-freedom velocity sensor or acceleration sensor, or a sensor group consisting of velocity sensors or acceleration sensors with three translational degrees of freedom and three rotational degrees of freedom.

[0038] In one specific implementation, the signal conditioner 10 includes an amplifier and a filter. The gain and bandwidth of the amplifier are adjustable, and the filter can perform high-pass filtering and its cutoff frequency is adjustable.

[0039] In one specific implementation, the materials of the fixed magnetic ring fixing part 3, the moving magnetic ring connecting part 5, the upper connecting part 161, the lower connecting part 162, the upper flexible hinge 171, the lower flexible hinge 172 and the helical spring 15 are non-magnetic or weakly magnetic aluminum alloy, titanium alloy or austenitic stainless steel.

[0040] In one specific implementation, the coil frame 7 is made of ceramic, granite, fiberglass, or rigid plastic.

[0041] The following is combined Figures 1-4 An embodiment of the present invention is given.

[0042] like Figures 1 to 4 As shown, the six-degree-of-freedom two-stage vibration isolator based on integrated negative stiffness damping control includes an upper plate 8, a middle plate 20, a base plate 1, and twelve sets of low-frequency vibration dampers 19 connected to the three in a Stewart manner. The upper plate 8 has a relative distance from the middle plate 20 along... x , y , z The three degrees of freedom of axis translation and the rotation around the axis x , y , z The three degrees of freedom of rotation of the shaft, the middle plate 20 relative to the base plate 1 has a lateral direction. x , y , z The three degrees of freedom of axis translation and the rotation around the axis x , y , z The shaft has three degrees of freedom for rotation. The tops of six sets of low-frequency vibration dampers 19 are connected to the fixing member 18 at the bottom of the upper plate 8 via four evenly distributed threaded holes on the upper flexible hinge 171, and their bottoms are connected to the fixing member 18 at the top of the middle plate 1 via four evenly distributed threaded holes on the lower flexible hinge 172. The tops of the other six sets of low-frequency vibration dampers 19 are connected to the fixing member 18 at the bottom of the middle plate 20 via four evenly distributed threaded holes on the upper flexible hinge 171, and their bottoms are connected to the fixing member 18 at the top of the base plate 1 via four evenly distributed threaded holes on the lower flexible hinge 172. The axes of two adjacent low-frequency vibration dampers 19 are perpendicular to each other.

[0043] Each low-frequency vibration damper 19 is composed of a helical spring 15 and a negative stiffness damping integrated controller 14 connected in parallel. The negative stiffness damping integrated controller 14 includes a fixed magnetic ring array 2, a fixed magnetic ring fixing component 3, a moving magnetic ring array 4, a moving magnetic ring connecting component 5, a coil 6, a coil frame 7, a sensor 9, a signal conditioner 10, a data acquisition unit 11, a controller 12, a driver 13, an upper connecting component 161, and a lower connecting component 162. The fixed magnetic ring fixing component 3, the fixed magnetic ring array 2, the moving magnetic ring connecting component 5, the moving magnetic ring array 4, the coil frame 7, and the coil 6 are coaxially nested and arranged sequentially from the axis outward along the radius, with the overall structure being axially symmetrical. The fixed magnetic ring fixing component 3 is a cylindrical structure with an inverted T-shaped cross-section, made of 7075 aluminum alloy, and its bottom... The coil frame 7 is fixedly connected to the coil coil 7 via four threaded holes evenly distributed around its circumference, with a certain gap between its top and the moving magnetic ring connector 5. The fixed magnetic ring array 2 is coaxially nested, tightly fitted, and fixedly installed on the outer side of the fixed magnetic ring fixing part 3, with gaps in both the radial and axial directions between it and the moving magnetic ring connector 5. The moving magnetic ring connector 5 is an annular sleeve made of 7075 aluminum alloy, with its top end fixedly connected to the upper connector 161 via four threaded holes evenly distributed around its circumference, and an annular boss with an annular groove inside the boss. The helical spring 15 is coaxially nested with the moving magnetic ring connector 5 and the coil frame 7, with its top end fixedly installed in the annular groove at the bottom of the moving magnetic ring connector 5 and its bottom end fixedly installed in the annular groove on the bottom surface of the coil frame 7. The helical spring 15 is a left-handed cylindrical helical spring made of stainless steel, and its positive stiffness characteristic is used to achieve stable support for vibration isolation loads. The moving magnetic ring array 4 is coaxially nested, tightly fitted, and fixedly installed on the outer side of the moving magnetic ring connector 5, with a radial gap between it and the coil frame 7. The coil frame 7 is an annular sleeve made of 99% alumina ceramic. Deep grooves are opened on its outer side along the circumference. The top maintains a certain gap with the upper flexible hinge 171, and the bottom is fixedly connected to the lower connector 162 through four threaded holes evenly distributed along the circumference.

[0044] Both the moving magnetic ring array 4 and the fixed magnetic ring array 2 consist of 2 n It consists of +1 layers of uniform cross-section magnetic rings arranged in an axial array, with adjacent layers perpendicularly magnetized. n ≥1, n∈N +The magnetic rings are all made of N50 neodymium iron boron, with a remanent magnetic induction of 1.43T and a relative permeability of 1.03. The inner and outer radii of the fixed magnetic ring array 2 are 1.3mm and 6.4mm, respectively. The height of the odd-numbered moving magnetic rings is 2mm, and the height of the even-numbered moving magnetic rings is 3.4mm. The inner and outer radii of the moving magnetic ring array 4 are 7mm and 10mm, respectively. The height of the odd-numbered fixed magnetic rings is 2mm, and the height of the even-numbered fixed magnetic rings is 3.4mm. The first layer of the fixed magnetic ring array 2 is magnetized radially towards the axis, while the first layer of the moving magnetic ring array 4 is magnetized radially outward from the axis. In the right half of the front sectional view, with each additional layer of magnetic rings, the magnetization direction of the fixed magnetic rings rotates 90° clockwise, and the magnetization direction of the moving magnetic rings rotates 90° counterclockwise. Coil 6 is formed by winding insulated copper enameled wire. It has a circular cross-section and is coaxially nested, tightly fitted, and fixedly mounted on the outer side of coil frame 7. Coil 6 is symmetrical about the axial height of the fixed magnetic ring array 2 and the moving magnetic ring array 4. Coil 6 is connected to the output of driver 13. The input of driver 13 is connected to the output of controller 12 via a serial port or network. Controller 12 integrates a control algorithm based on composite acceleration and velocity feedback. Its input reads information from acquisition unit 11 via a serial port or network. The input of acquisition unit 11 is connected to the output of signal conditioner 10, and the input of signal conditioner 10 is connected to sensor 9. When low-frequency vibration damper 19 is working, sensor 9 collects the vibration of the vibration-damping load supported by upper plate 8 in six degrees of freedom in real time. These vibration signals are then processed by signal conditioner 10, amplified to a detectable electrical signal level, and simultaneously filtered out high-frequency interference and DC bias. The processed signal is transmitted from the acquisition unit 11 to the controller 12. After processing, the controller 12 sends the voltage control signal to the driver 13 via a serial port or network. The driver 13 then converts the received voltage control signal into a corresponding control current and applies it to the coil 6.

[0045] Since the number of layers in both the moving magnetic ring array 4 and the fixed magnetic ring array 2 satisfies 2 n The relationship is +1, where... n ≥1, n∈N + Furthermore, the bottom surface of the first layer of magnetic rings in the fixed magnetic ring array 2 coincides with the bottom surface of the first layer of magnetic rings in the moving magnetic ring array 4. Therefore, the overall structure of the negative stiffness damping integrated controller 14 is related to the first... n+1 layer of magnetic rings are symmetrical. In this design, the magnetic force on the moving magnetic ring array 4 is zero, and it is in a balanced state. When the negative stiffness damping integrated controller 14 is connected in parallel with the helical spring 15, it does not affect the load-bearing capacity of the helical spring 15. However, under axial micro-perturbation excitation, the moving magnetic ring array 4 will move relative to the fixed magnetic ring array 2 and the coil 6. At this time, the axial balance of the moving magnetic ring array 4 is broken, while the radial balance remains. At this time, the axial magnetic force of the fixed magnetic ring array 2 acting on the moving magnetic ring array 4 is in the same direction as the vibration, causing it to continue to move away from the balance position. Without the action of external force, the balance cannot be restored on its own, that is, the axial magnetic force of the fixed magnetic ring array 2 acting on the moving magnetic ring array 4 exhibits negative stiffness characteristics. This characteristic can be used to control the vibration isolation bandwidth by generating negative stiffness characteristics without affecting the load of the helical spring 15. When the moving magnetic ring array 4 moves relative to the coil 6, the magnetic flux passing through the coil 6 changes. Under the coupling effect of the magnetic field and the electric field, the moving magnetic ring array 4 will be subjected to a damping force that is positively correlated with the speed of movement and opposite in direction, thereby converting the vibration energy into electrical energy and dissipating it in the form of heat energy.

[0046] The low-frequency vibration damper 19 can sense fluctuations in load mass and external excitation frequency in real time, and adjust the vibration isolation stiffness and damping accordingly to achieve precise coordination between the two, resulting in near-full-band and high-performance vibration isolation. The low-frequency vibration damper 19 utilizes a vertically magnetized fixed magnetic ring array 2, a moving magnetic ring array 4, and a coil 6 coaxially nested to achieve high negative stiffness and high damping characteristics. When the load mass changes or the external excitation frequency fluctuates, the sensor 9 instantly captures these dynamic changes and feeds the information back to the controller 12. The controller 12 uses a control algorithm based on acceleration and velocity composite feedback to adjust the current flowing through the coil 6, precisely controlling the vibration isolation stiffness and damping parameters. This ensures that the synergistic effect between the two, when used in parallel with the helical spring 15 to support the load platform, reduces the vibration isolation frequency to near zero frequency, significantly improving the vibration attenuation rate. This achieves the optimal state of near-full-band high-performance vibration isolation in multiple degrees of freedom, powerfully promoting a leapfrog improvement in the precision of precision instruments and equipment. Specifically, when the load mass increases, the controller 12 increases the current flowing through the coil 6 to enhance the axial magnetic force of the integrated negative stiffness damping controller 14. This allows it to provide greater negative stiffness and damping to balance the increased load mass, thereby ensuring that the vibration isolation system can still achieve high performance and near-full-band vibration isolation under heavy loads. Furthermore, when the excitation frequency decreases to near or below the natural frequency of the precision vibration isolation system, the controller 12 adjusts the magnitude and direction of the current flowing through the coil 6 to enhance the negative stiffness value of the integrated negative stiffness damping controller 14. This effectively reduces the natural frequency of the vibration isolation system, avoids resonance regions, ensures the vibration isolation system is free from resonance interference, and guarantees its long-term stable operation and high reliability.

Claims

1. A six-degree-of-freedom two-stage isolating microvibrator based on integrated control of negative stiffness damping, characterized in that: The system includes an upper plate (8), a middle plate (20), a base plate (1), and twelve sets of low-frequency vibration dampers (19) arranged in a Stewart configuration. The upper plate (8) has three translational degrees of freedom relative to the middle plate (20), and the middle plate (20) has three rotational degrees of freedom relative to the base plate (1). The tops of six sets of low-frequency vibration dampers (19) are connected to the bottom fixings (18) of the upper plate (8) via upper flexible hinges (171), and their bottoms are connected to the top fixings (18) of the middle plate (1) via lower flexible hinges (172). The tops of the other six sets of low-frequency vibration dampers (19) are connected to the bottom of the middle plate (20) via upper flexible hinges (171). The fixing member (18) is connected, and its bottom is connected to the fixing member (18) at the top of the substrate (1) through the lower flexible hinge (172). The axes of two adjacent low-frequency vibration dampers (19) are perpendicular to each other. The low-frequency vibration damper (19) is composed of a helical spring (15) and a negative stiffness damping integrated controller (14) connected in parallel. The negative stiffness damping integrated controller (14) includes a fixed magnetic ring array (2), a fixed magnetic ring fixing member (3), a moving magnetic ring array (4), a moving magnetic ring connector (5), a coil (6), a coil frame (7), a sensor (9), a signal conditioner (10), a data acquisition device (11), a controller (12), a driver (13), and an upper connector (161). The coil (6) is coaxially nested with the lower connector (162), the fixed magnetic ring fixing part (3), the fixed magnetic ring array (2), the moving magnetic ring connector (5), the moving magnetic ring array (4), the coil frame (7), and the coil (6), and arranged sequentially from the axis along the radius outwards. The overall structure is axially symmetrical. The fixed magnetic ring fixing part (3) is a cylindrical structure with an inverted T-shaped cross section. Its bottom is fixedly connected to the coil frame (7) by a thread, and its top maintains a certain gap with the moving magnetic ring connector (5). The fixed magnetic ring array (2) is coaxially nested, tightly fitted, and fixedly installed on the outer side of the fixed magnetic ring fixing part (3). It has gaps in both the radial and axial directions with the moving magnetic ring connector (5). The moving magnetic ring connector (5) is an annular sleeve. The top of the coil spring (15) is fixedly connected to the upper connector (161) by a thread, and the bottom is provided with an annular boss and an annular groove. The coil spring (15) is coaxially nested with the moving magnetic ring connector (5) and the coil frame (7). The top of the coil spring (15) is fixedly installed in the annular groove at the bottom of the moving magnetic ring connector (5), and the bottom is fixedly installed in the annular groove at the bottom of the coil frame (7). The moving magnetic ring array (4) is coaxially nested, tightly fitted and fixedly installed on the outer side of the moving magnetic ring connector (5), and has a radial gap with the coil frame (7). The fixed magnetic ring array (2) and the moving magnetic ring array (4) are both composed of multiple layers of axially arranged magnetic rings with perpendicular magnetization between adjacent layers, and the number of layers is 2. n +1, where, n ≥1, n∈N + The odd-numbered magnetic rings have the same height, and the even-numbered magnetic rings have the same height. The first layer of the fixed magnetic ring array (2) and the moving magnetic ring array (4) are magnetized in opposite directions along the radial direction. On the right half of the front sectional view, with each additional layer, the magnetization direction of the fixed magnetic ring rotates 90° clockwise, and the magnetization direction of the moving magnetic ring rotates 90° counterclockwise. The coil frame (7) is an annular sleeve with deep grooves on its outer side along the circumference. Its top maintains a certain gap with the upper flexible hinge (171), and its bottom is fixedly connected to the lower connector (162) by threads. The coil (6) is coaxially nested, tightly fitted, and fixedly installed on the outer side of the coil frame (7). The coil (6) is connected to the output end of the driver (13), and the input end of the driver (13) is connected to the control via a serial port or network. The output of the device (12) is connected to the controller (12), which integrates a control algorithm based on acceleration and velocity composite feedback. Its input end reads the information of the acquisition instrument (11) through a serial port or network. The input end of the acquisition instrument (11) is connected to the output end of the signal conditioner (10), and the input end of the signal conditioner (10) is connected to the sensor (9). The sensor (9) captures the change in load mass or the fluctuation of external excitation frequency and feeds the information back to the controller (12). The controller (12) adopts a control algorithm based on acceleration and velocity composite feedback to adjust the current in the coil (6), regulate the vibration isolation stiffness and damping parameters, and generate high damping characteristics for low-frequency vibration and low damping characteristics for high-frequency vibration.

2. The six-degree-of-freedom two-stage isolating microvibrator based on integrated control of negative stiffness damping according to claim 1, characterized in that: The fixed magnetic ring array (2) and the moving magnetic ring array (4) have the same height of magnetic rings in the same layer.

3. The six-degree-of-freedom two-stage isolating microvibrator based on integrated control of negative stiffness damping according to claim 1, characterized in that: The bottom surface of the first layer of magnetic rings in the fixed magnetic ring array (2) coincides with the bottom surface of the first layer of magnetic rings in the moving magnetic ring array (4).

4. The six-degree-of-freedom two-stage isolating microvibrator based on integrated control of negative stiffness damping according to claim 1, characterized in that: The height of the coil (6) is equal to the height of the fixed magnetic ring array (2), and is symmetrical about the axial height of the fixed magnetic ring array (2).

5. The six-degree-of-freedom two-stage isolating microvibrator based on integrated control of negative stiffness damping according to claim 1, characterized in that: The driver (13) is a linear regulator, a linear driver, a switching regulator, or a switching driver.

6. The six-degree-of-freedom two-stage isolating microvibrator based on integrated control of negative stiffness damping according to any one of claims 1 to 3, characterized in that: The radially magnetized magnetic rings in the fixed magnetic ring array (2) and the moving magnetic ring array (4) are composed of multiple radially uniformly magnetized tile-shaped magnets spliced ​​together. The number of tile-shaped magnets is 4, 5, 6, 8, 10, 12 or 15, and the gap between adjacent tile-shaped magnets does not exceed 3°.

7. The six-degree-of-freedom two-stage isolating microvibrator based on integrated control of negative stiffness damping according to claim 1, characterized in that: The sensor (9) is a single six-degree-of-freedom velocity sensor or acceleration sensor, or a sensor group consisting of three translational degrees of freedom and three rotational degrees of freedom velocity sensors or acceleration sensors.

8. The six-degree-of-freedom two-stage isolating microvibrator based on integrated control of negative stiffness damping according to claim 1, characterized in that: The signal conditioner (10) includes an amplifier and a filter. The gain and bandwidth of the amplifier are adjustable, and the filter can perform high-pass filtering and its cutoff frequency is adjustable.

9. The six-degree-of-freedom two-stage isolating microvibrator based on integrated control of negative stiffness damping according to claim 1, characterized in that: The materials of the fixed magnetic ring fixing part (3), the moving magnetic ring connecting part (5), the upper connecting part (161), the lower connecting part (162), the upper flexible hinge (171), the lower flexible hinge (172) and the helical spring (15) are non-magnetic or weakly magnetic aluminum alloy, titanium alloy or austenitic stainless steel.

10. The six-degree-of-freedom two-stage isolating microvibrator based on integrated control of negative stiffness damping according to claim 1, characterized in that: The coil frame (7) is made of ceramic, granite, fiberglass or hard plastic.

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