Three-degree-of-freedom micro-vibration isolator with adaptive co-regulation of stiffness and damping

Abstract

The three-degree-of-freedom micro-vibration isolator with stiffness and damping adaptive cooperative regulation belongs to the technical field of precision vibration isolation, and can realize three-degree-of-freedom near full-band vibration isolation performance under variable load. It comprises an upper plate, a base plate and three sets of low-frequency vibration isolation dampers connected between the upper plate and the base plate; the negative stiffness damping regulator in the low-frequency vibration isolation damper utilizes a multi-layer axial array of equal-section magnetic ring arrays with vertical magnetization between adjacent layers to construct a single-side high magnetic density excitation magnetic field, and coaxially nests the vertical magnetization permanent magnet ring array and the moving magnet ring array to generate high negative stiffness characteristics, and coaxially nests the coil to generate high damping characteristics; by real-time sensing the changes of the vibration isolation load mass or the excitation frequency, the size of the current in the energized coil is adjusted to generate a precisely controllable excitation magnetic flux, match the negative stiffness and damping requirements of near full-band vibration isolation, and achieve multi-directional, near full-band and high-performance vibration isolation effect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of precision vibration isolation, in particular to a three-degree-of-freedom micro-vibration isolator with adaptive and collaborative regulation of stiffness and damping. BACKGROUND

[0002] Low-frequency micro-amplitude vibration interference in the environment has become one of the key problems that limit the improvement of precision instrument equipment adjustment, testing and experimental precision. Providing low-frequency vibration isolation platforms for precision instruments and equipment has gradually become the main technical means to suppress environmental micro-vibration in the field of ultra-precision engineering. Stiffness and damping are the core parameters that determine the isolation bandwidth and isolation effect, and are directly related to the effect of the micro-vibration isolation platform on vibrations of different frequencies. How to effectively regulate them is the key to improving the isolation performance. Currently, the research on vibration isolation technology at home and abroad mainly focuses on single-degree-of-freedom systems, and focuses on the exploration of one-way adjustability of stiffness or damping.

[0003] However, in actual engineering applications, three-degree-of-freedom vibration isolation systems are particularly important because they can more comprehensively cope with complex spatial vibration environments, but research in this field is relatively scarce. Therefore, how to break through the limitations of existing technology and achieve integrated and collaborative regulation of vibration isolation stiffness and damping has become a key bottleneck in achieving high-performance vibration isolation in nearly full frequency bands and meeting high-precision requirements. Integrated and collaborative regulation of vibration isolation stiffness and damping means that the system can intelligently and real-time adjust the stiffness and damping parameters in a dynamically changing environment to achieve the optimal vibration suppression effect.

[0004] China Construction Eighth Engineering Corporation Limited (1. "A fabricated magnetic negative stiffness viscous damper", application number CN202310292721.3; 2. "A self-resetting SMA negative stiffness viscous damper", application number CN202320593107.6, a fabricated magnetic negative stiffness viscous damper;) discloses a negative stiffness damper composed of three magnetic negative stiffness structures arranged in an attractive manner and viscous liquid. The technical solution is characterized in that: (1) the direction of negative stiffness and damping generated by this structure is limited to single degree of freedom, and is not adjustable, making it difficult to effectively isolate multi-directional vibration interference, and lacking the ability to adaptively adjust with changes in load mass and excitation frequency; (2) the negative stiffness structure is composed of a same-direction magnetized permanent magnet piston and upper and lower fixed permanent magnets. The excitation magnetic field formed by the upper and lower fixed permanent magnets is symmetric about its height center, but only the magnetic field near the piston side produces negative stiffness characteristics, and the other side has high magnetic leakage, low magnetic field utilization rate, and limited negative stiffness value. The effect on the stiffness of heavy load or high frequency isolation system is very small; (3) the damping characteristics come from the damping force generated by the viscous liquid flowing through the gap between the piston and the cylinder when the permanent magnet piston moves, which converts vibration energy into heat energy. The properties of viscous liquid 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, or it may not work normally, affecting the damping effect and service life.

[0005] Patent No. 201410399913.5 discloses a magnetic negative stiffness damper that uses the relative motion of one or more pairs of axially magnetized first and second permanent magnets to produce negative stiffness characteristics, and uses the relative motion of the first magnet and the conductive tube to form an eddy current damping effect. The technical solution is characterized in that: (1) single degree of freedom magnetic negative stiffness damper is difficult to effectively isolate multi-directional vibration interference, and lacks the ability to adaptively adjust with changes in load mass and excitation frequency; (2) low magnetic field utilization rate, limited negative stiffness and damping value, poor effect on the stiffness and damping of heavy load or high frequency isolation system.

[0006] Patents CN202011189248.9, CN201610915703.6, CN201610834355.X, CN201510395953.7, CN201810300899.7, CN201811101215.7 and CN202311199383.5 all disclose multi-degree-of-freedom vibration isolators. The technical solutions of the above-mentioned patents are characterized in that: (1) for a magnetic ring uniformly magnetized in the radial or axial direction, only one side of the excitation magnetic field is utilized, the magnetic field utilization rate is low, the negative stiffness value generated is limited, and the effect on the stiffness of heavy load or high frequency isolation system is poor; (2) only has stiffness regulation function, but cannot adjust the isolation damping, limiting the improvement of vibration attenuation rate, and making it difficult to achieve high performance attenuation of full-band vibration.

[0007] In summary, how to design a three-degree-of-freedom micro-vibration isolator through vibration isolation structure and principle innovation, which can adaptively regulate the stiffness and damping of vibration isolation, can real-time perceive the changes of load mass and external excitation frequency, and regulate the stiffness and damping of vibration isolation according to the changes, so as to realize the precise cooperation between the two, and realize the high-performance vibration isolation effect of near full-band in multiple dimensions. This innovation not only effectively isolates the potential interference of environmental micro-vibration on precision instruments and equipment, but also provides a more stable and reliable operating environment for high-precision adjustment, testing and experimental work, which has far-reaching strategic significance for promoting scientific and technological progress and accelerating industrial upgrading. SUMMARY

[0008] The present application aims at the problem that the existing three-degree-of-freedom vibration isolator cannot simultaneously regulate the stiffness and damping, and is difficult to multi-directionally, near full-band and efficiently isolate the environmental micro-vibration interference, and proposes a three-degree-of-freedom micro-vibration isolator with adaptive and collaborative regulation of stiffness and damping, which is composed of an upper plate, a base plate and three sets of low-frequency vibration isolation dampers connecting the two. The negative stiffness damping regulator in the low-frequency vibration isolation damper utilizes a multi-layer axial array of equal-section magnetic ring arrays with vertical magnetization between adjacent layers to construct a single-side high magnetic density excitation magnetic field, and coaxially nests the vertical magnetization permanent ring array and the moving magnetic ring array to generate high negative stiffness characteristics, and coaxially nests the coil to generate adjustable high damping characteristics. By real-time perceiving the changes of vibration isolation load mass or excitation frequency, the size of the current in the energized coil is adjusted to generate a precisely controllable excitation magnetic flux, which matches the negative stiffness and damping requirements of near full-band vibration isolation, and achieves multi-directional, near full-band and high-performance vibration isolation effect.

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

[0010] The three-degree-of-freedom micro-vibration isolator with adaptive and collaborative regulation of stiffness and damping comprises an upper plate, a base plate and three sets of low-frequency vibration isolation dampers connecting the two, the upper plate has a degree of freedom of translational motion along the vertical z axis and a degree of freedom of rotation around the horizontal x and yThe top of each set of low-frequency vibration isolation dampers is connected with the fixing member at the bottom of the upper plate through the upper flexible hinge, and the connecting points are uniformly distributed along the circumference of the upper plate at intervals of 120°; the bottom of each set of low-frequency vibration isolation dampers is connected with the fixing member at the top of the base plate through the lower flexible hinge, and the connecting points are uniformly distributed along the circumference of the base plate at intervals of 120°; the low-frequency vibration isolation dampers are composed of a helical spring and a negative stiffness damping controller in parallel, the negative stiffness damping controller comprises a fixed magnet ring array, a fixed magnet array fixing member, a moving magnet ring array, a moving magnet array connecting member, a coil, a coil skeleton, a sensor, a signal conditioner, an acquisition instrument, a controller, a driver, an upper connecting member and a lower connecting member, the fixed magnet array fixing member, the fixed magnet ring array, the moving magnet array connecting member, the moving magnet ring array, the coil skeleton and the coil are coaxially nested, arranged in a gap outward along the radius from the shaft center, and the overall structure is axisymmetric; the fixed magnet array fixing member is a cylindrical structure with an inverted T-shaped cross section, the bottom thereof is fixedly connected with the coil skeleton through a thread, and the top thereof is kept a certain gap with the moving magnet array connecting member; the fixed magnet ring array is coaxially nested, tightly fitted and fixedly installed on the outer side surface of the fixed magnet array fixing member, and gaps are provided in the radial and axial directions; the moving magnet array connecting member is an annular sleeve, the top thereof is fixedly connected with the upper connecting member through a thread, the bottom thereof is provided with an annular boss, and an annular groove is arranged in the boss; the helical spring is coaxially nested with the moving magnet array connecting member and the coil skeleton, the top thereof is fixedly installed in the annular groove at the bottom of the moving magnet array connecting member, and the bottom thereof is fixedly installed in the annular groove on the bottom surface of the coil skeleton; the moving magnet ring array is coaxially nested, tightly fitted and fixedly installed on the outer side surface of the moving magnet array connecting member, and gaps are provided in the radial direction; the fixed magnet ring array and the moving magnet ring array are each composed of a plurality of layers (the number of layers is 2 n +1, wherein n ≥1, n ∈ N + ) are composed of equal-section magnetic rings arranged in an array along the axial direction and vertically magnetized between adjacent layers, wherein the heights of the magnetic rings of the odd-numbered layers are equal, and the heights of the magnetic rings of the even-numbered layers are equal; the first magnetic rings of the fixed magnet ring array and the moving magnet ring array are oppositely magnetized in the radial direction, in the right half of the front view, with each additional layer, the magnetization direction of the fixed magnet ring rotates clockwise by 90°, and the magnetization direction of the moving magnet ring rotates counterclockwise by 90°; the coil skeleton is an annular sleeve with a deep groove formed on the outer side surface along the circumference, the top thereof is kept a certain gap with the upper flexible hinge, and the bottom thereof is fixedly connected with the lower connecting member through a thread; the coil is coaxially nested, tightly fitted and fixedly installed on the outer side surface of the coil skeleton, the coil is connected with the output end of the driver, the input end of the driver is connected with the output end of the controller through a serial port or a network, the controller is integrated with a control algorithm based on acceleration and speed compound feedback, the input end of the controller reads the information of the acquisition instrument through a serial port or a network, the input end of the acquisition instrument is connected with the output end of the signal conditioner, and the input end of the signal conditioner is connected with the sensor.

[0011] Preferably, the height of the stator magnetic ring array is equal to the height of the stator magnetic ring array.

[0012] Preferably, the bottom surface of the first layer of the stator magnetic ring array coincides with the bottom surface of the first layer of the stator magnetic ring array.

[0013] Preferably, the height of the coil is equal to the height of the stator magnetic ring array, and the coil is symmetric about the axial height center of the stator magnetic ring array.

[0014] Preferably, the driver is a linear voltage regulator, a linear driver, a switching voltage regulator, or a switching driver.

[0015] Preferably, the stator magnetic ring array and the stator magnetic ring array are made of multiple radially uniform magnet tiles, and the number of tiles can be 4, 5, 6, 8, 10, 12, and 15, and the gap between adjacent tiles is not more than 3°.

[0016] Preferably, the sensor is a single three-degree-of-freedom velocity sensor or acceleration sensor, or a sensor group composed of a translational degree-of-freedom velocity sensor or acceleration sensor and a two-rotational degree-of-freedom velocity sensor or acceleration sensor.

[0017] Preferably, the signal conditioner includes an amplifier and a filter, the gain and bandwidth of the amplifier are adjustable, and the filter can realize high-pass filtering function, and the cutoff frequency is adjustable.

[0018] Preferably, the materials of the stator magnetic array fixing member, the stator magnetic array connecting member, the upper connecting member, the lower connecting member, the upper flexible hinge, the lower flexible hinge, and the coil skeleton are non-magnetic or weakly magnetic aluminum alloy, titanium alloy, or austenitic stainless steel.

[0019] Preferably, the material of the coil skeleton is ceramic, granite, glass steel, or hard plastic.

[0020] The technical innovation and good effects of the present application are as follows:

[0021] (1) The technical scheme utilizes the coaxial nesting of the vertical magnetic stator magnetic ring array and the stator magnetic ring array to generate high negative stiffness characteristics, and the coaxial nesting with the coil to generate adjustable high damping characteristics, the magnetic field utilization rate is high, and the system energy consumption is low. The low-frequency vibration isolation damper utilizes the coaxial nesting of the vertical magnetic stator magnetic ring array and the stator magnetic ring array to generate high negative stiffness characteristics, and the coaxial nesting with the coil to generate adjustable high damping characteristics, the magnetic field utilization rate is high, and the system energy consumption is low. n +1( n ≥1, n e N +) Layer along the axial array, the vertical magnetization of adjacent layers, the cross section of the magnetic ring array is constructed on one side of the high magnetic density excitation magnetic field, and the vertical magnetization of the magnetic ring array is coaxially nested with the dynamic magnetic ring array and the coil to generate high negative stiffness and adjustable damping characteristics. The single-sided high magnetic density excitation magnetic field can not only effectively weaken the magnetic field strength of the non-working side, but also can significantly enhance the magnetic field strength of the working side, improve the negative stiffness and damping value of the low-frequency vibration isolator, and expand the vibration isolation frequency band and damping adjustment range. This is one of the innovations of the present application which is different from the prior art.

[0022] (2) The technical scheme can sense the fluctuation of load quality and external excitation frequency in real time, and adjust the vibration isolation stiffness and damping according to the fluctuation, so as to realize the precise cooperation between the two, and achieve the effect of nearly full-band and high-performance vibration isolation in three degrees of freedom. The low-frequency vibration isolator utilizes the coaxial nesting of the vertical magnetization of the magnetic ring array and the dynamic magnetic ring array and the coil to generate high negative stiffness and high damping characteristics; when the load quality changes or the external excitation frequency fluctuates, the sensor captures these dynamic changes in real time and feeds back the information to the controller. The controller adjusts the current in the coil by integrating the control algorithm based on acceleration and speed composite feedback, accurately adjusts the vibration isolation stiffness and damping parameters, and ensures the cooperation between the two when the load platform is supported in parallel with the spiral spring, so as to reduce the vibration isolation frequency to nearly zero frequency, greatly improve the vibration attenuation rate, and thus achieve the optimal state of nearly full-band high-performance vibration isolation in three degrees of freedom. This is the second innovation of the present application which is different from the prior art.

[0023] (3) The present application realizes the cooperative regulation of the stiffness and damping parameters of the micro-vibration isolator by generating adjustable high negative stiffness and low-frequency high damping, high-frequency low damping. By utilizing the dynamic response, the stiffness and damping of the spiral spring are cooperatively regulated to match the stiffness and damping parameters of the nearly full-band vibration isolation range and the full-frequency high-performance vibration isolation, so as to maximize the vibration isolation frequency band and the vibration isolation effect. This cooperative regulation design effectively avoids the performance bottleneck that may be encountered by single parameter adjustment, gives the precision vibration isolation system stronger environmental adaptability and dynamic adjustment capability, so that it can flexibly cope with complex scenes such as changes in load quality, fluctuations in excitation frequency and diversified vibration isolation requirements. This is the third innovation of the present application which is different from the prior art. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a three-dimensional model of the three-degree-of-freedom micro-vibration isolator with stiffness and damping adaptive cooperative regulation.

[0025] Figure 2 It is a schematic diagram of the arrangement of three sets of low-frequency vibration isolators.

[0026] Figure 3 It is a three-dimensional sectional view of the low-frequency vibration isolator.

[0027] Figure 4A front view of the low-frequency vibration isolation damper.

[0028] Figure number explanation: 1 substrate, 2 fixed magnet ring array, 3 fixed magnet array fixing part, 4 moving magnet ring array, 5 moving magnet array connecting part, 6 coil, 7 coil skeleton, 8 upper plate, 9 sensor, 10 signal conditioner, 11 acquisition instrument, 12 controller, 13 driver, 14 negative stiffness damping controller, 15 spiral 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. DETAILED DESCRIPTION

[0029] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0030] The three-degree-of-freedom micro-vibration isolator with stiffness and damping adaptive cooperative control includes an upper plate 8, a substrate 1, and three sets of low-frequency vibration isolation dampers 19 connecting the two, the upper plate 8 has a degree of freedom of moving along the vertical z axis and a degree of freedom of rotating around the horizontal x and yThe top of each set of low-frequency vibration isolation dampers 19 is connected to the fixed part 18 at the bottom of the upper plate 8 through the upper flexible hinge 171, and the connection points are evenly distributed at an interval of 120° along the circumference of the upper plate 8; the bottom of each set of low-frequency vibration isolation dampers 19 is connected to the fixed part 18 at the top of the base plate 1 through the lower flexible hinge 172, and the connection points are evenly distributed at an interval of 120° along the circumference of the base plate 1; characterized in that: the low-frequency vibration isolation dampers 19 are composed of a spiral spring 15 and a negative stiffness damping controller 14 in parallel, the negative stiffness damping controller 14 includes a fixed magnet ring array 2, a fixed magnet array fixing part 3, a moving magnet ring array 4, a moving magnet array connecting part 5, a coil 6, a coil skeleton 7, a sensor 9, a signal conditioner 10, a collection instrument 11, a controller 12, a driver 13, an upper connecting part 161 and a lower connecting part 162, the fixed magnet array fixing part 3, the fixed magnet ring array 2, the moving magnet array connecting part 5, the moving magnet ring array 4, the coil skeleton 7 and the coil 6 are coaxially nested, arranged in a gap along the radius outward from the shaft center, and the overall structure is axisymmetric; the fixed magnet array fixing part 3 is a cylindrical structure with an inverted T-shaped cross section, the bottom is fixedly connected with the coil skeleton 7 through threads, and the top keeps a certain gap with the moving magnet array connecting part 5; the fixed magnet ring array 2 is coaxially nested and tightly fitted and fixedly installed on the outer side surface of the fixed magnet array fixing part 3, and gaps are provided in the radial and axial directions with the moving magnet array connecting part 5; the moving magnet array connecting part 5 is an annular sleeve, the top end is fixedly connected with the upper connecting part 161 through threads, the bottom is provided with an annular boss, and an annular groove is arranged in the boss; the spiral spring 15 is coaxially nested with the moving magnet array connecting part 5 and the coil skeleton 7, the top end is fixedly installed in the annular groove at the bottom of the moving magnet array connecting part 5, and the bottom is fixedly installed in the annular groove on the bottom surface of the coil skeleton 7; the moving magnet ring array 4 is coaxially nested, tightly fitted and fixedly installed on the outer side surface of the moving magnet array connecting part 5, and gaps are provided in the radial direction with the coil skeleton 7; the fixed magnet ring array 2 and the moving magnet ring array 4 are each composed of multiple layers (the number of layers is 2 n +1, wherein n ≥1, n ∈ N +) along the axial array, the vertical magnetization between adjacent layers, wherein the height of the odd layer magnetic ring is equal, the height of the even layer magnetic ring is equal; the first layer magnetic ring of the fixed magnetic ring array 2 and the moving magnetic ring array 4 is radially magnetized, and in the right half of the front view, the magnetization direction of the fixed magnetic ring rotates clockwise by 90°, and the magnetization direction of the moving magnetic ring rotates counterclockwise by 90° with each layer increasing; the coil skeleton 7 is an annular sleeve with a deep groove on the outer side along the circumference, and the top is kept a certain gap with the upper flexible hinge 171, and the bottom is fixedly connected with the lower connecting piece 162 through threads; the coil 6 is coaxially nested, tightly fitted and fixedly installed on the outer side of the coil skeleton 7, the coil 6 is connected with the output end of the driver 13, the input end of the driver 13 is connected with the output end of the controller 12 through a serial port or a network, the controller 12 is integrated with a control algorithm based on acceleration and speed compound feedback, the input end of the controller 12 reads the information of the acquisition instrument 11 through a serial port or a network, the input end of the acquisition instrument 11 is connected with the output end of the signal conditioner 10, and the input end of the signal conditioner 10 is connected with the sensor 9.

[0031] As a specific embodiment, the height of the same layer magnetic ring of the fixed magnetic ring array 2 and the moving magnetic ring array 4 is equal.

[0032] As a specific embodiment, the bottom surface of the first layer magnetic ring in the fixed magnetic ring array 2 coincides with the bottom surface of the first layer magnetic ring in the moving magnetic ring array 4.

[0033] As a specific embodiment, the height of the coil 6 is equal to the height of the fixed magnetic ring array 2, and is symmetric about the axial height center of the fixed magnetic ring array 2.

[0034] As a specific embodiment, the driver 13 is a linear voltage stabilizer, a linear driver, a switching type voltage stabilizer or a switching type driver.

[0035] As a specific embodiment, the radially magnetized magnetic ring in the fixed magnetic ring array 2 and the moving magnetic ring array 4 is spliced by a plurality of radially uniform magnetized tile-shaped magnets, the number of tile-shaped magnets can be 4, 5, 6, 8, 10, 12 and 15, and the gap between adjacent tile-shaped magnets is not more than 3°.

[0036] As a specific embodiment, the sensor 9 is a single three-degree-of-freedom velocity sensor or acceleration sensor, or a sensor group composed of a translational degree-of-freedom and two rotational degrees-of-freedom velocity sensor or acceleration sensor.

[0037] As a specific embodiment, the signal conditioner 10 includes an amplifier and a filter, the gain and bandwidth of the amplifier are adjustable, the filter can realize high-pass filtering function, and the cutoff frequency is adjustable.

[0038] As a specific embodiment, the material of the fixed magnet array fixing member 3, the moving magnet array 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 is non-magnetic or weakly magnetic aluminum alloy, titanium alloy or austenitic stainless steel.

[0039] As a specific embodiment, the material of the coil former 7 is ceramic, granite, glass fiber reinforced plastic or hard plastic.

[0040] An embodiment of the present application is given below. Figures 1-4 An embodiment of the present application is given below.

[0041] As shown in Figure 1 and Figure 2 , the present application comprises the upper plate 8, the base plate 1 and three sets of low-frequency vibration isolation dampers 19 connecting the two. The upper plate 8 has the freedom of translation along the vertical z-axis and the freedom of rotation around the horizontal x and y axes relative to the base plate 1. The top of each set of low-frequency vibration isolation dampers 19 is connected to the fixing member 18 on the bottom of the upper plate 8 through the four evenly distributed threaded holes on the upper flexible hinge 171, and the connection points are evenly distributed along the circumference of the upper plate 8 at an interval of 120°. The bottom of each set of low-frequency vibration isolation dampers 19 is connected to the fixing member 18 on the top of the base plate 1 through the four evenly distributed threaded holes on the lower flexible hinge 172, and the connection points are evenly distributed along the circumference of the base plate 1 at an interval of 120°.

[0042] As shown in Figures 1-4As shown, each set of low-frequency vibration isolation damper 19 is composed of a helical spring 15 and a negative stiffness damping controller 14 in parallel, the negative stiffness damping controller 14 includes a fixed magnet ring array 2, a fixed magnet array fixing piece 3, a moving magnet ring array 4, a moving magnet array 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 magnet array fixing piece 3, the fixed magnet ring array 2, the moving magnet array connecting piece 5, the moving magnet ring array 4, the coil skeleton 7 and the coil 6 are coaxially nested, arranged in a radial outward gap from the shaft center, and the overall structure is axisymmetric; the fixed magnet array fixing piece 3 is a cylindrical structure with an inverted T-shaped cross section, made of 7075 aluminum alloy, fixedly connected with the coil skeleton 7 through four evenly distributed threaded holes on the bottom, and kept a certain gap with the moving magnet array connecting piece 5 on the top; the fixed magnet ring array 2 is coaxially nested, tightly fitted and fixedly installed on the outer side of the fixed magnet array fixing piece 3, and gaps are provided in the radial and axial directions with the moving magnet array connecting piece 5; the moving magnet array connecting piece 5 is an annular sleeve made of 7075 aluminum alloy, fixedly connected with the upper connecting piece 161 through four evenly distributed threaded holes on the top, provided with an annular boss on the bottom, and an annular groove is arranged in the boss; the helical spring 15 is coaxially nested with the moving magnet array connecting piece 5 and the coil skeleton 7, fixedly installed in the annular groove on the bottom of the moving magnet array connecting piece 5 on the top, and fixedly installed in the annular groove on the bottom surface of the coil skeleton 7 on the bottom. The helical spring 15 is a left-handed cylindrical helical spring made of stainless steel, and its positive stiffness characteristic is used to stably support the vibration isolation load. The moving magnet ring array 4 is coaxially nested, tightly fitted and fixedly installed on the outer side of the moving magnet array connecting piece 5, and gaps are provided in the radial direction with the coil skeleton 7. The moving magnet ring array 4 and the fixed magnet ring array 2 are both composed of 2 n +1( n ≥1, n e N + ) layers of equal-section magnetic rings arranged in an axial array and vertically magnetized between adjacent layers, the material of the magnetic rings is N50 grade neodymium iron boron, the residual magnetic induction intensity is 1.43T, and the relative magnetic permeability is 1.03. The inner radius and outer radius of the fixed magnet ring array 2 are 1.3mm and 6.4mm respectively, the height of the odd-numbered layer of moving magnet rings is 2mm, and the height of the even-numbered layer of moving magnet rings is 3.4mm. The inner radius and outer radius of the moving magnet ring array 4 are 7mm and 10mm respectively, the height of the odd-numbered layer of fixed magnet rings is 2mm, and the height of the even-numbered layer of fixed magnet rings is 3.4mm.

[0043] The first layer of magnetic rings of the fixed magnetic ring array 2 and the moving magnetic ring array 4 are radially magnetized in opposite directions, and on the right half of the front view, the magnetization direction of the fixed magnetic ring rotates clockwise by 90° and the magnetization direction of the moving magnetic ring rotates counterclockwise by 90° with each added layer. The coil skeleton 7 is an annular sleeve made of 99 alumina ceramic, and a deep groove is formed on the outer side along the circumference, the top is kept a certain gap with the upper flexible hinge 171, and the bottom is fixedly connected with the lower connecting piece 162 through four evenly distributed threaded holes along the circumference. The coil 6 is formed by winding insulated copper enameled wire, and the cross section is circular, coaxially nested, tightly fitted and fixedly installed on the outer side of the coil skeleton 7, and the coil 6 is centrally symmetric about the axial height of the fixed magnetic ring array 2 and the moving magnetic ring array 4. The coil 6 is connected with the output end of the driver 13, the input end of the driver 13 is connected with 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 speed compound feedback, the input end of the controller 12 reads the information of the acquisition instrument 11 through a serial port or a network, the input end of the acquisition instrument 11 is connected with the output end of the signal conditioner 10, and the input end of the signal conditioner 10 is connected with the sensor 9. When the low-frequency vibration isolation damper 19 is working, the sensor 9 can collect the vibrations of the vibration isolation load supported by the upper plate 8 in three 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 at the same time filtered to remove high-frequency interference and DC bias. The processed signal is transmitted to the controller 12 by the acquisition instrument 11, and after being processed by the control algorithm based on acceleration and speed compound feedback, the controller 12 sends a voltage control signal to the driver 13 through a serial port or a network. The driver 13 converts the received voltage control voltage signal into a corresponding control current and loads it onto the coil 6.

[0044] Since the number of layers of the moving magnetic ring array 4 and the fixed magnetic ring array 2 satisfies the relationship of 2 n +1( n ≥1, n e 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 moving magnetic ring array 4, the overall structure of the negative stiffness damping regulator 14 is centrally symmetric about the first nThe +1 layer magnetic ring is symmetrical up and down. In this design, the magnetic force acting on the moving magnetic ring array 4 is zero, and it is in a state of balance. When the negative stiffness damping controller 14 is connected in parallel with the helical spring 15, it does not affect the load capacity of the helical spring 15. However, under the excitation of axial micro-disturbance, the moving magnetic ring array 4 will move relative to the fixed magnetic ring array 2 and the coil 6, at which time the axial balance state of the moving magnetic ring array 4 is broken, while the radial balance is still maintained. At this time, the axial magnetic force acting on the moving magnetic ring array 4 by the fixed magnetic ring array 2 is in the same direction as the vibration direction, so that it continues to move away from the balance position, and under the action of no external force, the balance cannot be restored by itself, that is, the axial magnetic force acting on the moving magnetic ring array 4 by the fixed magnetic ring array 2 presents a negative stiffness characteristic. This characteristic can regulate the vibration isolation bandwidth of the helical spring 15 without affecting its load, and only by generating a negative stiffness characteristic. 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 action of the magnetic field and the electric field, the moving magnetic ring array 4 will be subjected to a damping force which is positively correlated with the speed of movement and is in the opposite direction, thereby converting vibration energy into electrical energy and dissipating it in the form of heat energy.

[0045] The low-frequency vibration isolation damper 19 can sense the fluctuations of the load mass and external excitation frequency in real time, and accordingly regulate the vibration isolation stiffness and damping to achieve precise coordination between the two, achieving near full-band and high-performance vibration isolation effect. The low-frequency vibration isolation damper 19 utilizes the vertically magnetized fixed magnetic ring array 2 and moving magnetic ring array 4, and the coil 6 coaxially nested to generate high negative stiffness and high damping characteristics; when the load mass changes or the external excitation frequency fluctuates, the sensor 9 captures these dynamic changes in real time and feeds back the information to the controller 12. The controller 12 uses a control algorithm based on acceleration and speed compound feedback to adjust the current in the coil 6, accurately regulating the vibration isolation stiffness and damping parameters, ensuring the synergy between the two, when the helical spring 15 is connected in parallel to support the load platform, the vibration isolation frequency is reduced to near zero frequency, greatly improving the vibration attenuation rate, so as to achieve the optimal state of near full-band high-performance vibration isolation in multiple degrees of freedom, and powerfully promote the leap-forward improvement of the precision 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 controller 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 effect under large load mass. In addition, when the excitation frequency is reduced to near or below the natural frequency of the precision micro-vibration isolation system, the controller 12 will adjust the size and direction of the current in the coil 6 to enhance the negative stiffness value of the negative stiffness damping controller 14, thereby effectively reducing the vibration isolation natural frequency, avoiding the resonance region, ensuring that the vibration isolation system is not disturbed by resonance, and ensuring its long-term stable operation and high reliability.

Claims

1. A three-degree-of-freedom micro-vibration isolator with stiffness and damping adaptive co-regulation, comprising an upper plate (8), a base plate (1) and three sets of low-frequency vibration isolation dampers (19) connecting the two, the upper plate (8) has a degree of freedom of translation along the vertical z axis and a degree of freedom of rotation around the horizontal x and y axis relative to the base plate (1), the top end of each set of low-frequency vibration isolation dampers (19) is connected to the fixed part (18) at the bottom of the upper plate (8) through an upper flexible hinge (171), and the connection points are uniformly distributed at an interval of 120° on the circumference of the upper plate (8); the bottom of each set of low-frequency vibration isolation dampers (19) is connected to the fixed part (18) at the top of the base plate (1) through a lower flexible hinge (172), and the connection points are uniformly distributed at an interval of 120° on the circumference of the base plate (1); characterized in that: The low-frequency vibration isolation damper (19) is composed of a helical spring (15) and a negative stiffness damping controller (14) in parallel, the negative stiffness damping controller (14) comprising a fixed magnet ring array (2), a fixed magnet array fixing piece (3), a moving magnet ring array (4), a moving magnet array connecting piece (5), a coil (6), a coil skeleton (7), a sensor (9), a signal conditioner (10), an acquisition instrument (11), a controller (12), a driver (13), an upper connecting piece (161) and a lower connecting piece (162), the fixed magnet array fixing piece (3), the fixed magnet ring array (2), the moving magnet array connecting piece (5), the moving magnet ring array (4), the coil skeleton (7) and the coil (6) are coaxially nested, arranged outward along the radius gap from the shaft center, and the overall structure is axisymmetric; the fixed magnet array fixing piece (3) is a cylindrical structure with an inverted T-shaped cross section, the bottom is fixedly connected with the coil skeleton (7) through threads, and the top keeps a certain gap with the moving magnet array connecting piece (5); the fixed magnet ring array (2) is coaxially nested, tightly fitted and fixedly installed on the outer side surface of the fixed magnet array fixing piece (3), and gaps are provided in the radial and axial directions; the moving magnet array connecting piece (5) is an annular sleeve, the top end is fixedly connected with the upper connecting piece (161) through threads, the bottom is provided with an annular boss, and an annular groove is arranged in the boss; the helical spring (15) is coaxially nested with the moving magnet array connecting piece (5) and the coil skeleton (7), the top end is fixedly installed in the annular groove at the bottom of the moving magnet array connecting piece (5), and the bottom is fixedly installed in the annular groove on the bottom surface of the coil skeleton (7); the moving magnet ring array (4) is coaxially nested, tightly fitted and fixedly installed on the outer side surface of the moving magnet array connecting piece (5), and gaps are provided in the radial direction; the fixed magnet ring array (2) and the moving magnet ring array (4) each comprise a plurality of layers (the number of layers is 2 n +1, wherein n ≥1, n ∈ N + ) The equal cross section magnetic rings are arranged in axial array and vertically magnetized between adjacent layers, wherein the heights of the odd layer magnetic rings are equal and the heights of the even layer magnetic rings are equal; the first layer magnetic rings of the fixed magnetic ring array (2) and the moving magnetic ring array (4) are radially and oppositely magnetized, and in the right half of the front view, with each layer increased, the magnetization direction of the fixed magnetic ring rotates clockwise by 90° and the magnetization direction of the moving magnetic ring rotates counterclockwise by 90°; the coil skeleton (7) is an annular sleeve with deep grooves opened on the outer side surface along the circumference, the top of which keeps a certain gap with the upper flexible hinge (171) and the bottom of which is fixedly connected with the lower connecting piece (162) through screw threads; the coil (6) is coaxially nested, tightly fitted and fixedly installed on the outer side surface of the coil skeleton (7), the coil (6) is connected with the output end of the driver (13), the input end of the driver (13) is connected with the output end of the controller (12) through a serial port or a network, the controller (12) is integrated with a control algorithm based on acceleration and speed compound feedback, the input end of the controller (12) reads the information of the acquisition instrument (11) through a serial port or a network, the input end of the acquisition instrument (11) is connected with the output end of the signal conditioner (10), and the input end of the signal conditioner (10) is connected with the sensor (9).

2. The stiffness and damping co-adapted tri-DOF microvibro-isolator according to claim 1, wherein: The height of the fixed magnetic ring array (2) is equal to the height of the same layer magnetic ring of the moving magnetic ring array (4).

3. The stiffness and damping co-adapted tri-DOF microvibro-isolator of claim 1, wherein: The bottom surface of the first layer magnetic ring of the fixed magnetic ring array (2) coincides with the bottom surface of the first layer magnetic ring of the moving magnetic ring array (4).

4. The stiffness and damping co-adapted tri-DOF microvibro-isolator of claim 1, wherein: The height of the coil (6) is equal to the height of the fixed magnetic ring array (2), and is symmetric about the axial height center of the fixed magnetic ring array (2).

5. The stiffness and damping co-adapted tri-DOF microvibro-isolator of claim 1, wherein: The driver (13) is a linear voltage regulator, a linear driver, a switching voltage regulator or a switching driver.

6. The stiffness and damping co-adapted tri-DOF microvibro-isolator of claim 1, wherein: The magnetic rings along the radial magnetization in the fixed magnetic ring array (2) and the moving magnetic ring array (4) are spliced by multiple tiles of the radial uniform magnetization tile-shaped magnet, the number of the tiles of the tile-shaped magnet can be 4, 5, 6, 8, 10, 12 and 15, and the gap between the adjacent tile-shaped magnets is not more than 3°.

7. The stiffness and damping co-adapted tri-DOF microvibro-isolator of claim 1, wherein: The sensor (9) is a single three-degree-of-freedom velocity sensor or acceleration sensor, or a sensor group composed of a velocity sensor or acceleration sensor with one translational degree of freedom and two rotational degrees of freedom.

8. The stiffness and damping co-adapted tri-DOF microvibro-isolator of claim 1, wherein: The signal conditioner (10) includes an amplifier and a filter, the gain and bandwidth of the amplifier are adjustable, the filter can realize high-pass filtering function, and the cutoff frequency thereof is adjustable.

9. The stiffness and damping co-adapted tri-DOF microvibro-isolator of claim 1, wherein: The materials of the fixed magnetic array fixing member (3), the moving magnetic array 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 skeleton (7) are non-magnetic or weakly magnetic aluminum alloy, titanium alloy or austenitic stainless steel.

10. The stiffness and damping co-adapted tri-DOF microvibro-isolator of claim 1, wherein: The material of the coil skeleton (7) is ceramic, granite, glass steel or hard plastic.

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