Six-degree-of-freedom two-stage micro-vibration isolator based on negative stiffness and damping integrated regulation and control

Abstract

The invention discloses a six-degree-of-freedom two-stage micro-vibration isolator based on negative stiffness and damping integrated regulation and control, belongs to the technical field of precise vibration isolation, and realizes multi-degree-of-freedom near-full-band vibration isolation performance under variable load by utilizing twelve sets of low-frequency vibration isolation dampers which are connected with an upper plate and a base plate and are arranged in a Stewart mode. According to the low-frequency vibration isolation damper, a negative stiffness and damping integrated regulator and a spiral spring are connected in parallel to support a load platform, the negative stiffness and damping integrated regulator constructs a single-side high-flux-density excitation magnetic field through multiple layers of uniform-section magnetic ring arrays which are arranged in an array mode in the axial direction and vertically magnetized between the adjacent layers, and the magnetic field intensity of the non-working side is effectively weakened; the vertically magnetized fixed magnetic ring array and the moving magnetic ring array are coaxially nested to realize the high negative stiffness characteristic, and are coaxially nested with the coil to realize the high damping characteristic, and local low dynamic stiffness and adjustable high damping characteristics can be generated under the large bearing condition by regulating and controlling the energizing current of the coil; and the rigidity and damping parameters for realizing near-full-band high-performance vibration isolation at multiple degrees of freedom are accurately matched.

Description

Technical Field

[0001] The invention belongs to the technical field of precision vibration isolation, in particular to a six-degree-of-freedom two-stage micro-vibration isolation device based on integrated regulation of negative stiffness and damping. Background Art

[0002] Low-frequency micro-vibration has become one of the key factors restricting the improvement of precision in the installation, adjustment, testing and experiment of precision instruments and equipment. To solve this problem, configuring a low-frequency vibration isolation platform for precision equipment has become a key technical means in the field of ultra-precision engineering. The core of the performance of the vibration isolation platform lies in its stiffness and damping. These two parameters directly affect the vibration isolation platform's suppression effect on vibrations of various frequencies. Specifically, the vibration isolation platform has a "low-pass filtering" characteristic, and its stiffness characteristics determine the starting vibration isolation frequency and the vibration isolation bandwidth. The lower the stiffness, the lower the starting vibration isolation frequency and the wider the vibration isolation bandwidth; while the damping characteristics determine the vibration attenuation efficiency of the vibration isolation platform. Low damping is conducive to attenuating high-frequency vibrations, while high damping is conducive to reducing the platform's transmission rate to low-frequency vibrations. Therefore, precise control of these two parameters is the key to improving the overall performance of the vibration isolation platform and achieving high-precision vibration suppression.

[0003] At present, the research on control technology mainly focuses on single-degree-of-freedom vibration isolation systems, focusing on single-item adjustment of stiffness or damping. However, research on six degrees of freedom that are more in line with actual application scenarios and can fully and efficiently attenuate vibration interference in complex and changeable spatial environments is relatively scarce. In addition, single adjustment of stiffness or damping is prone to performance bottlenecks, and it is difficult to take into account the dual optimization of vibration isolation effect and vibration isolation bandwidth. How to achieve coordinated integrated control of vibration isolation stiffness and damping in six degrees of freedom to broaden the vibration isolation frequency band and improve vibration attenuation efficiency has become a major problem that restricts breakthroughs in all-round, full-band high-performance vibration isolation technology and meets high-precision application requirements.

[0004] Patent No. 201910634275.3 discloses a quasi-zero stiffness vibration isolation and energy harvesting system based on the Stewart platform. This technical solution uses annular permanent magnets and electromagnets arranged in a vertical array to provide semi-active negative stiffness to offset the positive stiffness of the diaphragm spring. The introduction of electromagnets makes the negative stiffness adjustable, adapting to changes in the mass of the vibration isolation load and the excitation frequency, increasing the vibration isolation frequency band, and achieving a lower frequency vibration isolation effect. The characteristics of this technical solution are: (1) The uniform magnetization of the annular permanent magnet causes the excitation magnetic field generated by it to be utilized only near the electromagnet side, with low magnetic field utilization and limited negative stiffness value, which has poor effect on the stiffness of heavy load or high-frequency vibration isolation systems; (2) It only has the stiffness control function, but cannot adjust the vibration isolation damping, which limits the improvement of the vibration attenuation rate and makes it difficult to achieve high-performance attenuation of full-band 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 above technical solutions are characterized in that: (1) for a magnetic ring uniformly magnetized in the radial or axial direction, the excitation magnetic field generated is only utilized on one side, the magnetic field utilization rate is low, the negative stiffness value generated is limited, and the stiffness of the heavy-load or high-frequency vibration isolation system is not effective; (2) it only has the stiffness control function, but cannot adjust the vibration isolation damping, which limits the improvement of the vibration attenuation rate and makes it difficult to achieve high-performance attenuation of full-band vibration; (3) it can only attenuate the 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 variable damping vibration isolator consisting of an air spring and six sets of magnetorheological dampers. The stiffness is adjusted by changing the amount of gas in the airbag through the air hole, and the damping force of each set of magnetorheological dampers is changed by adjusting the coil input current. The characteristics of this technical solution are: (1) Due to the limitations of the structure and material stiffness, the natural frequency of the air spring cannot be reduced to zero by adjusting the amount of gas in the airbag, 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. In high or low temperature environments, its damping performance may change and may even fail to work properly; (3) Long-term use or improper use may cause residue to form inside the magnetorheological damper, affecting the damping effect and service life; (4) The vibration attenuation rate can only reach 20dB / dec.

[0007] In summary, how to provide a micro-vibration isolator that can adaptively and collaboratively adjust the vibration isolation stiffness and damping, and can perform multi-level and multi-freedom attenuation of vibration interference through innovation of vibration isolation structure and principle, and dynamically adjust the vibration isolation stiffness and damping based on the real-time perception of load mass changes and external six-degree-of-freedom excitation frequency fluctuations, and accurately match the stiffness and damping parameters to achieve all-round, near-full-band and high-performance vibration isolation, thereby isolating the influence of environmental micro-vibrations on precision instruments and equipment, creating a more stable and reliable environment for high-precision assembly, testing and experimental work, which is of strategic significance for promoting scientific and technological progress and accelerating industrial upgrading. Summary of the invention

[0008] The purpose of the present invention is to address the problem that the existing six-degree-of-freedom vibration isolators cannot take into account the coordinated adaptive regulation of stiffness and damping, and it is difficult to isolate environmental micro-vibration interference in an all-round, near-full-band, and efficient manner. A six-degree-of-freedom two-stage micro-vibration isolator based on the integrated regulation of negative stiffness and damping is proposed. Twelve sets of low-frequency vibration isolation dampers arranged by Stewart are connected to the upper plate and the base plate to achieve multi-degree-of-freedom near-full-band vibration isolation. These dampers are supported in parallel by negative stiffness damping regulators and spiral springs, and a single-sided high magnetic density magnetic field is constructed using a multi-layer vertical magnetization magnetic ring array to weaken the magnetic field on the non-working side. The fixed magnetic ring array and the dynamic magnetic ring array and the coil are coaxially nested to achieve high negative stiffness and eddy current damping. The coil current is regulated by a control algorithm based on acceleration and velocity composite feedback, which can produce low dynamic stiffness and low-frequency high damping and high-frequency low damping characteristics under large loads, accurately matching the requirements of multi-degree-of-freedom vibration isolation, adapting to load and frequency changes, and significantly improving the vibration attenuation rate.

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

[0010] A six-degree-of-freedom two-stage micro-vibration isolation device based on integrated control of negative stiffness damping includes an upper plate, a middle plate, a base plate, and twelve sets of low-frequency vibration isolation dampers connected in a Stewart manner. 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. Among them, the top of six sets of low-frequency vibration isolation dampers are connected to the fixing part at the bottom of the upper plate through an upper flexible hinge, and the bottom thereof is connected to the fixing part at the top of the middle plate through a lower flexible hinge. The top of another six sets of low-frequency vibration isolation dampers are connected to the fixing part at the bottom of the middle plate through an upper flexible hinge, and the bottom thereof is connected to the fixing part at the top of the base plate through a lower flexible hinge. The axes of two adjacent low-frequency vibration isolation dampers are perpendicular to each other. The low-frequency vibration isolation damper is integrated with a coil spring and negative stiffness damping. The regulator is constructed in parallel, and the negative stiffness damping integrated regulator 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 skeleton, a sensor, a signal conditioner, a collector, a controller, a driver, an upper connecting part and a lower connecting part. The fixed magnetic ring fixing part, the fixed magnetic ring array, the moving magnetic ring connecting part, the moving magnetic ring array, the coil skeleton and the coil are coaxially nested and arranged in sequence from the axis along the radius outward, and the overall structure is axially symmetrical; the fixed magnetic ring fixing part is a cylindrical structure with an inverted T-shaped cross-section, the bottom of which is fixedly connected to the coil skeleton by a thread, and the top maintains a certain gap with the moving magnetic ring connecting part; the fixed magnetic ring array is coaxially nested, tightly matched, and fixedly installed on the outer side of the fixed magnetic ring fixing part, and there is a gap with the moving magnetic ring connecting part in the radial and axial directions. ; The moving magnetic ring connecting piece is an annular sleeve, the top of which is fixedly connected to the upper connecting piece by a thread, and an annular boss is arranged at the bottom, and an annular groove is arranged in the boss; the spiral spring is coaxially nested with the moving magnetic ring connecting piece and the coil skeleton, and the top of which is fixedly installed in the annular groove at the bottom of the moving magnetic ring connecting piece, and the bottom is fixedly installed in the annular groove on the bottom surface of the coil skeleton; the moving magnetic ring array is coaxially nested, tightly fitted, and fixedly installed on the outer side surface of the moving magnetic ring connecting piece, and a gap is provided with the coil skeleton along the radial direction; the fixed magnetic ring array and the moving magnetic ring array are both composed of multiple layers of equal-section magnetic rings arranged in an axial array and vertically magnetized between adjacent layers, wherein the heights of the odd-numbered magnetic rings are equal, and the heights of the even-numbered magnetic rings are equal; the first layer of the fixed magnetic ring array and the moving magnetic ring array are magnetized in opposite directions along the radial direction, and in the positive On the right half of the cross-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 skeleton is an annular sleeve with deep grooves on the outer side along the circumference, the top of which maintains a certain gap with the upper flexible hinge, and the bottom is fixedly connected to the lower connecting piece by a thread; the coil is coaxially nested, tightly fitted, and fixedly installed on the outer side of the coil skeleton, the coil is connected to the output end of the driver, and the input end of the driver is connected to the output end of the controller through a serial port or a network. The controller integrates a control algorithm based on composite feedback of acceleration and velocity, and its input end reads the information of the collector through a serial port or a network, the input end of the collector is connected to the output end of the signal conditioner, and the input end of the signal conditioner is connected to the sensor.

[0011] The input end of the driver is connected to the output end of the collector, the input end of the collector is connected to the output end of the signal conditioner, the input end of the signal conditioner is connected to the sensor, and the collector is connected to the controller through a serial port or a network.

[0012] Preferably, the number of layers of the fixed magnetic ring array and the dynamic magnetic ring array is 2n+1, where n≥1, n∈N + .

[0013] Preferably, the heights of the magnetic rings in the same layer of the fixed magnetic ring array and the moving magnetic ring array are equal.

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

[0015] Preferably, the height of the coil is equal to the height of the fixed magnetic ring array, and is symmetrical about the axial height center of the fixed magnetic ring array.

[0016] Preferably, the driver is a linear regulator, a linear driver, a switching regulator or a switching driver.

[0017] Preferably, the radially magnetized magnetic rings in the fixed magnetic ring array and the moving 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°.

[0018] 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.

[0019] Preferably, the signal conditioner includes an amplifier and a filter, the gain and bandwidth of the amplifier are adjustable, the filter can realize a high-pass filtering function, and its cut-off frequency is adjustable.

[0020] Preferably, the fixed magnetic ring fixing part, the moving magnetic ring connecting part, the upper connecting part, 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.

[0021] Preferably, the coil skeleton is made of ceramic, granite, fiberglass or hard plastic.

[0022] The technical innovation and good effects of the present invention are:

[0023] (1) This technical solution uses the vertical magnetization of the fixed magnetic ring array and the dynamic magnetic ring array to coaxially nest to achieve high negative stiffness characteristics, and coaxial nesting with the coil to achieve adjustable high damping characteristics, high magnetic field utilization, and low system energy consumption. The low-frequency vibration isolation damper uses 2n+1 (n≥1, n∈N + ) layers are arranged in an axial array, and an equal-section magnetic ring array with perpendicular magnetization between adjacent layers constructs a unilateral high magnetic density excitation magnetic field, and the vertically magnetized fixed magnetic ring array and the dynamic magnetic ring array and the coil are coaxially nested to achieve high negative stiffness and adjustable high damping characteristics. The unilateral high magnetic density excitation magnetic field can not only effectively weaken the magnetic field strength on the non-working side, but also significantly enhance the magnetic field strength on the working side, improve the negative stiffness and damping value of the low-frequency vibration isolation damper, and expand the vibration isolation frequency band and damping adjustment range. This is one of the innovative points that distinguish the present invention from the prior art.

[0024] (2) This technical solution can sense the fluctuations of load mass and external excitation frequency in real time, and adjust the vibration isolation stiffness and damping accordingly, so as to achieve precise coordination between the two and achieve near full-band and high-performance vibration isolation effects in six degrees of freedom. The low-frequency vibration isolation damper uses a vertically magnetized fixed magnetic ring array and a dynamic magnetic ring array, and coaxially nested coils to achieve high negative stiffness and eddy current damping characteristics; when the load mass changes or the external excitation frequency fluctuates, the sensor instantly captures these dynamic changes and feeds the information back to the controller. The controller uses a control algorithm based on acceleration and velocity composite feedback to adjust the current in the coil, accurately adjust 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 and the coil spring are connected in parallel 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 innovation of the present invention that distinguishes it from the prior art.

[0025] (3) The present invention adopts a double-layer vibration isolation structure, which can effectively attenuate vibration interference from three translational degrees of freedom and three rotational degrees of freedom. The double-layer vibration isolation structure is composed of twelve sets of low-frequency vibration isolation dampers connected to the upper plate and the base plate in a Stewart manner, which can increase the vibration attenuation rate from 20dB / Dec to 40dB / Dec. Faced with the same vibration interference, the double-layer vibration isolation structure can more efficiently reduce the transmission and amplification of vibration, thereby ensuring that the system has higher stability and reliability. The double-layer vibration isolation system is significantly better than the single-layer vibration isolation system in terms of medium and high frequency vibration isolation effect, and can still obtain a considerable vibration isolation effect when the mass ratio is less than the integral type. In addition, by optimizing structural parameters such as damping ratio, mass ratio and stiffness ratio, a better low-frequency vibration isolation effect can be achieved than the equivalent linear vibration isolation system. This is the third innovation that distinguishes the present invention from the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1It is a three-dimensional model of a six-degree-of-freedom two-stage micro-vibrator based on integrated control of negative stiffness and damping;

[0027] Figure 2 This is a schematic diagram of the arrangement of twelve sets of low-frequency vibration isolation dampers;

[0028] Figure 3 is a three-dimensional cross-sectional schematic diagram of a low-frequency vibration isolation damper;

[0029] Figure 4 It is a front cross-sectional view of the low frequency vibration isolation damper;

[0030] Description of the part numbers in the figure: 1 substrate, 2 fixed magnetic ring array, 3 fixed magnetic ring fixing part, 4 dynamic magnetic ring array, 5 dynamic magnetic ring connecting part, 6 coil, 7 coil skeleton, 8 upper plate, 9 sensor, 10 signal conditioner, 11 collector, 12 controller, 13 driver, 14 negative stiffness damping integrated controller, 15 coil spring, 161 upper connecting part, 162 lower connecting part, 171 upper flexible hinge, 172 lower flexible hinge, 18 fixing part, 19 low-frequency vibration isolation damper, 20 middle plate. DETAILED DESCRIPTION

[0031] The specific implementation modes of the present invention are described in detail below with reference to the accompanying drawings.

[0032] A six-degree-of-freedom two-stage micro-vibration isolation device based on integrated control of negative stiffness damping comprises 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 manner. The upper plate 8 has three translational degrees of freedom and three rotational degrees of freedom relative to the middle plate 20 and the middle plate 20 has three translational degrees of freedom relative to the base plate 1. Among them, the tops of six sets of low-frequency vibration isolation dampers 19 are connected to the fixing member 18 at the bottom of the upper plate 8 through an upper flexible hinge 171, and the bottoms thereof are connected to the fixing member 18 at the top of the middle plate 1 through a lower flexible hinge 172. The tops of the other six sets of low-frequency vibration isolation dampers 19 are connected to the fixing member 18 at the bottom of the middle plate 20 through an upper flexible hinge 171, and the bottoms thereof are connected to the fixing member 18 at the top of the base plate 1 through a lower flexible hinge 172. The fixing piece 18 of the lower part is connected, and the axes of two adjacent low-frequency vibration isolation dampers 19 are perpendicular to each other; the low-frequency vibration isolation damper 19 is composed of a coil spring 15 and a negative stiffness damping integrated regulator 14 in parallel, and the negative stiffness damping integrated regulator 14 includes a fixed magnetic ring array 2, a fixed magnetic ring fixing piece 3, a moving magnetic ring array 4, a moving magnetic ring connecting piece 5, a coil 6, a coil skeleton 7, a sensor 9, a signal conditioner 10, a collector 11, a controller 12, a driver 13, an upper connecting piece 161 and a lower connecting piece 162, the fixed magnetic ring fixing piece 3, the fixed magnetic ring array 2, the moving magnetic ring connecting piece 5, the moving magnetic ring array 4, the coil skeleton 7 and the coil 6 are coaxially nested, and are arranged in sequence from the axis along the radius outward, and the overall structure is axially symmetrical; the fixed magnetic ring fixing piece 3, the fixed magnetic ring array 2, the moving magnetic ring connecting piece 5, the moving magnetic ring array 4, the coil skeleton 7 and the coil 6 are coaxially nested, and are arranged in sequence from the axis along the radius outward, and the overall structure is axially symmetrical; The fixed part 3 is a cylindrical structure with an inverted T-shaped cross-section, the bottom of which is fixedly connected to the coil skeleton 7 by a thread, and the top maintains a certain gap with the dynamic magnetic ring connecting part 5; the fixed magnetic ring array 2 is coaxially nested, tightly matched, and fixedly installed on the outer side of the fixed magnetic ring fixing part 3, and has gaps with the dynamic magnetic ring connecting part 5 in the radial and axial directions; the dynamic magnetic ring connecting part 5 is an annular sleeve, the top of which is fixedly connected to the upper connecting part 161 by a thread, and an annular boss is arranged at the bottom, and an annular groove is arranged in the boss; the spiral spring 15 is coaxially nested with the dynamic magnetic ring connecting part 5 and the coil skeleton 7, the top of which is fixedly installed in the annular groove at the bottom of the dynamic magnetic ring connecting part 5, and the bottom is fixedly installed in the annular groove on the bottom surface of the coil skeleton 7; the dynamic magnetic ring array 4 is coaxially nested, tightly matched, and fixedly installed on the outer side of the fixed magnetic ring fixing part 3, and has gaps with the dynamic magnetic ring connecting part 5 in the radial and axial directions; the dynamic magnetic ring connecting part 5 is an annular sleeve, the top of which is fixedly connected to the upper connecting part 161 by a thread, and an annular boss is arranged at the bottom, and an annular groove is arranged in the boss; the spiral spring 15 is coaxially nested with the dynamic magnetic ring connecting part 5 and the coil skeleton 7, and the top of which is fixedly installed in the annular groove at the bottom of the dynamic magnetic ring connecting part 5, and the bottom is fixedly installed in the annular groove on the bottom surface of the coil skeleton 7; It is matched and fixedly installed on the outer side of the moving magnetic ring connector 5, and has a gap with the coil skeleton 7 along the radial direction; the fixed magnetic ring array 2 and the moving magnetic ring array 4 are both composed of multiple layers of equal-section magnetic rings arranged in an axial array and vertically magnetized between adjacent layers, wherein the heights of the odd-numbered layers of magnetic rings are equal, and the heights of the even-numbered layers of magnetic rings are equal; 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, and on the right half of the front cross-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 skeleton 7 is an annular sleeve with deep grooves on the outer side along the circumference, the top of which maintains a certain gap with the upper flexible hinge 171, and the bottom is fixedly connected to the lower connector 162 through a thread;The coil 6 is coaxially nested, tightly matched, and fixedly mounted on the outer side of the coil frame 7. The coil 6 is connected to the output end of the driver 13. The input end of the driver 13 is connected to the output end of the collector 11. The input end of the collector 11 is connected to the output end of the signal conditioner 10. The input end of the signal conditioner 10 is connected to the sensor 9. The collector 11 is connected to the controller 12 via a serial port or a network.

[0033] As a specific implementation, the number of layers of the fixed magnetic ring array 2 and the moving magnetic ring array 4 is 2n+1, where n≥1, n∈N + .

[0034] As a specific implementation manner, 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.

[0035] As a specific implementation manner, 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 .

[0036] As a specific implementation manner, 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 center of the fixed magnetic ring array 2 .

[0037] As a specific implementation, the driver 13 is a linear regulator, a linear driver, a switching regulator or a switching driver.

[0038] As a specific implementation method, the radially magnetized magnetic rings in the fixed magnetic ring array 2 and the moving magnetic ring array 4 are composed of 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°.

[0039] As a specific implementation, the 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.

[0040] As a specific implementation, the signal conditioner 10 includes an amplifier and a filter. The gain and bandwidth of the amplifier are adjustable. The filter can realize a high-pass filtering function, and its cut-off frequency is adjustable.

[0041] As a 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 coil spring 15 are non-magnetic or weakly magnetic aluminum alloy, titanium alloy or austenitic stainless steel.

[0042] As a specific implementation, the material of the coil skeleton 7 is ceramic, granite, fiberglass or hard plastic.

[0043] Combine the following Figure 1 to Figure 4 An embodiment of the present invention is given.

[0044] like Figures 1 to 4 As shown, the six-degree-of-freedom two-stage micro-vibration isolation device based on integrated control of negative stiffness damping 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 manner. The upper plate 8 has three degrees of freedom along the x, y, and z axes and three degrees of freedom around the x, y, and z axes relative to the middle plate 20. The middle plate 20 has three degrees of freedom along the x, y, and z axes and three degrees of freedom around the x, y, and z axes relative to the base plate 1. Among them, the top ends of six sets of low-frequency vibration isolation dampers 19 are connected to the fixing part 18 at the bottom of the upper plate 8 through four threaded holes evenly distributed on the upper flexible hinge 171, and the bottom ends are connected to the fixing part 18 at the top of the middle plate 1 through four threaded holes evenly distributed on the lower flexible hinge 172. The top ends of another six sets of low-frequency vibration isolation dampers 19 are connected to the fixing part 18 at the bottom of the middle plate 20 through four threaded holes evenly distributed on the upper flexible hinge 171, and the bottom ends are connected to the fixing part 18 at the top of the base plate 1 through four threaded holes evenly distributed on the lower flexible hinge 172. The axes of two adjacent low-frequency vibration isolation dampers 19 are perpendicular to each other.

[0045] Each set of low-frequency vibration isolation damper 19 is composed of a coil spring 15 and a negative stiffness damping integrated regulator 14 in parallel. The negative stiffness damping integrated regulator 14 includes a fixed magnetic ring array 2, a fixed magnetic ring fixing part 3, a dynamic magnetic ring array 4, a dynamic magnetic ring connecting part 5, a coil 6, a coil skeleton 7, a sensor 9, a signal conditioner 10, a collector 11, a controller 12, a driver 13, an upper connecting part 161 and a lower connecting part 162. The fixed magnetic ring fixing part 3, the fixed magnetic ring array 2, the dynamic magnetic ring connecting part 5, the dynamic magnetic ring array 4, the coil skeleton 7 and the coil 6 are coaxially nested and arranged in sequence from the axis along the radius outward, and the overall structure is axially symmetrical; the fixed magnetic ring fixing part 3 is a cylindrical structure with an inverted T-shaped cross-section, and the material is 7075 aluminum alloy, and its bottom It is fixedly connected to the coil frame 7 through four threaded holes evenly distributed along the circumference, and a certain gap is maintained between the top and the moving magnetic ring connector 5; the fixed magnetic ring array 2 is coaxially nested, tightly matched, and fixedly installed on the outer side of the fixed magnetic ring fixture 3, and there are gaps with the moving magnetic ring connector 5 in the radial and axial directions; the moving magnetic ring connector 5 is an annular sleeve, made of 7075 aluminum alloy, and its top is fixedly connected to the upper connector 161 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 spiral spring 15 is coaxially nested with the moving magnetic ring connector 5 and the coil frame 7, and its top is fixedly installed in the annular groove at the bottom of the moving magnetic ring connector 5, and its bottom is fixedly installed in the annular groove at the bottom of the coil frame 7. The spiral spring 15 is a left-handed cylindrical spiral spring made of stainless steel, and its positive stiffness characteristics are used to achieve stable support of vibration isolation loads; the moving magnetic ring array 4 is coaxially nested, tightly matched, and fixedly installed on the outer side of the moving magnetic ring connector 5, and there are gaps with the coil frame 7 in the radial direction. The coil skeleton 7 is an annular sleeve made of 99 alumina ceramics, with deep grooves 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 connecting piece 162 through four threaded holes evenly distributed along the circumference.

[0046] The moving magnetic ring array 4 and the fixed magnetic ring array 2 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 fixed magnetic ring array 2 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 moving magnetic ring array 4 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 fixed magnetic ring array 2 is magnetized along the radius to the axis, and the first layer of the moving magnetic ring array 4 is magnetized from the axis along the radius to the outside. On the right half of the front section view, with each additional layer of magnetic rings, 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 6 is formed by winding an insulated copper enameled wire, and its cross section is circular. It is coaxially nested, tightly fitted, and fixedly mounted on the outer side of the coil skeleton 7. The coil 6 is symmetrical about the axial height center of the fixed magnetic ring array 2 and the dynamic magnetic ring array 4. 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 output end of the controller 12 through a serial port or a network. The controller 12 integrates a control algorithm based on the composite feedback of acceleration and velocity, and its input end reads the information of the collector 11 through a serial port or a network. The input end of the collector 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. When the low-frequency vibration isolation damper 19 is working, the sensor 9 will collect the vibration of the vibration isolation load supported by the upper plate 8 in six degrees of freedom in real time. These vibration signals are then processed by the signal conditioner 10, amplified to a detectable electrical signal level, and high-frequency interference and DC bias are filtered out at the same time. The processed signal is transmitted from the collector 11 to the controller 12. After the operation is processed, the controller 12 sends the voltage control signal to the driver 13 through the serial port or the network. The driver 13 converts the received voltage control voltage signal into a corresponding control current and loads it onto the coil 6.

[0047] Since the number of layers of the moving magnetic ring array 4 and the fixed magnetic ring array 2 satisfies 2n+1 (n≥1, n∈N +), and 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 dynamic magnetic ring array 4. Therefore, the overall structure of the negative stiffness damping integrated regulator 14 is symmetrical about the n+1th layer of magnetic rings. Under this design, the magnetic force on the dynamic magnetic ring array 4 is zero and is in a balanced state. When the negative stiffness damping integrated regulator 14 is connected in parallel with the coil spring 15, it does not affect the bearing capacity of the coil spring 15. However, under axial micro-disturbance excitation, the dynamic magnetic ring array 4 will move relative to the fixed magnetic ring array 2 and the coil 6. At this time, the axial equilibrium state of the dynamic magnetic ring array 4 is broken, while the radial balance is still maintained. At this time, the axial magnetic force of the fixed magnetic ring array 2 acting on the dynamic magnetic ring array 4 is the same as the vibration direction, so that it continues to move away from the equilibrium position, and in the absence of external force, the balance cannot be restored by itself, that is, the axial magnetic force of the fixed magnetic ring array 2 acting on the dynamic magnetic ring array 4 presents a negative stiffness characteristic. This characteristic can regulate the vibration isolation bandwidth of the coil spring 15 by only generating negative stiffness characteristics without affecting the load of the coil spring 15. When the dynamic magnetic ring array 4 moves relative to the coil 6, the magnetic flux passing through the coil 6 changes; under the coupling of the magnetic field and the electric field, the dynamic magnetic ring array 4 will be subjected to a damping force that is positively correlated with the movement speed and in the opposite direction, thereby converting the vibration energy into electrical energy and dissipating it in the form of heat energy.

[0048] The low-frequency vibration isolation damper 19 can sense the fluctuations of the load mass and the external excitation frequency in real time, and adjust the vibration isolation stiffness and damping accordingly, so as to achieve precise coordination between the two and achieve near full-band and high-performance vibration isolation effects. The low-frequency vibration isolation damper 19 uses the coaxial nesting of the vertically magnetized fixed magnetic ring array 2 and the dynamic magnetic ring array 4 and the coil 6 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 in the coil 6, accurately adjust the vibration isolation stiffness and damping parameters, and ensure that the synergy between the two reduces the vibration isolation frequency to near zero frequency when supporting the load platform in parallel with the coil spring 15, greatly improving the vibration attenuation rate, thereby achieving the optimal state of near full-band high-performance vibration isolation in multiple degrees of freedom, and effectively promoting the leapfrog improvement of the accuracy of precision instruments and equipment. Specifically, when the load mass increases, the controller 12 will increase the current in the coil 6 to enhance the axial magnetic force of the negative stiffness damping integrated regulator 14, so that it can 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 effects under a large 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 12 will adjust the magnitude and direction of the current in the coil 6 to enhance the negative stiffness value of the negative stiffness damping integrated regulator 14, 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 ensuring its long-term stable operation and high reliability.

Claims

1. A six-degree-of-freedom two-stage microvibrator based on integrated control of negative stiffness and damping, characterized by: The invention comprises 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 a fixing member (18) at the bottom of the upper plate (8) through an upper flexible hinge (171), and the bottoms thereof are connected to a fixing member (18) at the top of the middle plate (1) through a lower flexible hinge (172). The tops of the other six sets of low-frequency vibration isolation dampers (19) are connected to a fixing member (18) at the bottom of the middle plate (20) through an upper flexible hinge (171). 8), the bottom of which is connected to the fixing member (18) at the top of the base plate (1) through a lower flexible hinge (172), and the axes of two adjacent low-frequency vibration isolation dampers (19) are perpendicular to each other; the low-frequency vibration isolation damper (19) is composed of a coil spring (15) and a negative stiffness damping integrated controller (14) in parallel, and the negative stiffness damping integrated controller (14) includes a fixed magnetic ring array (2), a fixed magnetic ring fixing member (3), a dynamic magnetic ring array (4), a dynamic magnetic ring connecting member (5), a coil (6), a coil skeleton (7), a sensor (9), a signal conditioner (10), a collector (11), a controller (12), a driver (13), an upper connecting member (161) and a lower connecting member (162 ), the fixed magnetic ring fixing part (3), the fixed magnetic ring array (2), the dynamic magnetic ring connecting part (5), the dynamic magnetic ring array (4), the coil skeleton (7) and the coil (6) are coaxially nested and arranged in sequence from the axis along the radius outward, and the overall structure is axially symmetrical; the fixed magnetic ring fixing part (3) is a cylindrical structure with an inverted T-shaped cross-section, the bottom of which is fixedly connected to the coil skeleton (7) by a thread, and the top of which maintains a certain gap with the dynamic magnetic ring connecting part (5); the fixed magnetic ring array (2) is coaxially nested, tightly matched, and fixedly installed on the outer side surface of the fixed magnetic ring fixing part (3), and has a gap with the dynamic magnetic ring connecting part (5) in the radial direction and the axial direction; the dynamic magnetic ring connecting part (5) is an annular sleeve, the top of which is connected to the upper connecting part (16) by a thread. 1) fixedly connected, an annular boss is arranged at the bottom, and an annular groove is arranged in the boss; the spiral spring (15) is coaxially nested with the moving magnetic ring connecting piece (5) and the coil frame (7), and its top end is fixedly installed in the annular groove at the bottom of the moving magnetic ring connecting piece (5), and the bottom end is fixedly installed in the annular groove on the bottom surface of the coil frame (7); the moving magnetic ring array (4) is coaxially nested, tightly matched, and fixedly installed on the outer side surface of the moving magnetic ring connecting piece (5), and a gap is provided with the coil frame (7) in the radial direction; the fixed magnetic ring array (2) and the moving magnetic ring array (4) are both composed of multiple layers of equal-section magnetic rings arranged in an axial array and perpendicularly magnetized between adjacent layers, wherein the heights of the odd-numbered layers of magnetic rings are equal, and the heights of the even-numbered layers of magnetic rings are equal;The first layers of the fixed magnetic ring array (2) and the moving magnetic ring array (4) are magnetized in opposite directions in the radial direction. On the right half of the front cross-sectional view, with each additional layer, 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 skeleton (7) is an annular sleeve with deep grooves formed along the circumference of the outer side surface. The top of the coil skeleton maintains a certain gap with the upper flexible hinge (171), and the bottom is fixedly connected to the lower connecting piece (162) through a thread. The coil (6) is coaxially nested, tightly matched, and fixedly installed on the line. On the outer side of the coil frame (7), the coil (6) is connected to the output end of the driver (13), the input end of the driver (13) is connected to the output end of the controller (12) through a serial port or a network, the controller (12) integrates a control algorithm based on acceleration and velocity composite feedback, the input end of the controller (12) reads information from the collector (11) through a serial port or a network, the input end of the collector (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).

2. The six-degree-of-freedom two-stage micro-vibration isolation device based on integrated control of negative stiffness and damping according to claim 1 is characterized in that: The number of layers of the fixed magnetic ring array (2) and the dynamic magnetic ring array (4) is 2n+1, where n≥1, n∈N + .

3. The six-degree-of-freedom two-stage micro-vibration isolation device based on integrated control of negative stiffness and damping according to claims 1 and 2 is characterized in that: 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.

4. The six-degree-of-freedom two-stage micro-vibration isolation device based on integrated control of negative stiffness and damping according to claims 1 to 3, characterized in that: The bottom surface of the first layer of magnetic rings in the fixed magnetic ring array (2) overlaps with the bottom surface of the first layer of magnetic rings in the moving magnetic ring array (4).

5. The six-degree-of-freedom two-stage micro-vibration isolation device based on integrated control of negative stiffness and damping according to claim 1 is 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 center of the fixed magnetic ring array (2).

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

7. The six-degree-of-freedom two-stage micro-vibration isolation device based on integrated control of negative stiffness and damping according to claims 1 to 4, characterized in that: The radially magnetized magnetic rings in the fixed magnetic ring array (2) and the moving magnetic ring array (4) are formed by splicing a plurality of tile-shaped magnets uniformly magnetized in the radial direction. The number of tile-shaped magnets can be 4, 5, 6, 8, 10, 12 or 15, and the gap between adjacent tile-shaped magnets does not exceed 3°.

8. The six-degree-of-freedom two-stage micro-vibration isolation device based on integrated control of negative stiffness and damping according to claim 1 is characterized in that: The 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.

9. The six-degree-of-freedom two-stage micro-vibration isolation device based on integrated control of negative stiffness and damping according to claim 1 is characterized in that: The signal conditioner (10) comprises an amplifier and a filter. The gain and bandwidth of the amplifier are adjustable. The filter can realize a high-pass filtering function and its cut-off frequency is adjustable.

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

11. The six-degree-of-freedom two-stage micro-vibration isolation device based on integrated control of negative stiffness and damping according to claim 1 is characterized in that: The material of the coil frame (7) is ceramic, granite, glass fiber reinforced plastic or hard plastic.

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