A bidirectional adjustable electromagnetic quasi-zero stiffness vibration isolation device and control method

Abstract

This invention provides a bidirectional adjustable electromagnetic quasi-zero stiffness vibration isolation device and control method, belonging to the field of vibration isolation technology. The device includes a fixed support frame, a suspended support frame, a positive stiffness module, and a negative stiffness module. The fixed support frame includes upper and lower fixed plates spaced apart vertically; the suspended support frame is disposed therebetween and includes a horizontal support plate, a guide rod, and a loading platform; the positive stiffness module consists of a first disc-type motor assembly on the inner ring of the upper and lower fixed plates and an annular permanent magnet on the inner ring of the horizontal support plate, providing electromagnetic support force to form positive stiffness; the negative stiffness module consists of a second disc-type motor assembly on the outer ring of the upper and lower fixed plates and an annular magnetic plate on the outer ring of the horizontal support plate, providing electromagnetic attraction force to form negative stiffness; both are coaxially connected in parallel and act on the horizontal support plate. By independently or simultaneously adjusting the energizing current, the quasi-zero stiffness of the vibration isolation system is achieved. This invention has a compact, contactless structure and can achieve bidirectional dynamic adjustment of stiffness.

Description

Technical Field

[0001] This invention relates to the field of low-frequency isolation technology, and in particular to a bidirectional adjustable electromagnetic quasi-zero stiffness vibration isolation device and control method. Background Technology

[0002] The core design concept of quasi-zero stiffness vibration isolation technology is to make the overall stiffness of the system approach zero at the static equilibrium position through the coupling and control of positive and negative stiffness elements. This achieves extremely low natural frequency to efficiently isolate low-frequency vibrations while maintaining high static stiffness to constrain static deformation, thus accurately achieving the ideal vibration isolation goal of "high static and low dynamic".

[0003] Currently, electromagnetic quasi-zero stiffness isolators have become a research hotspot in the field of vibration control due to their excellent low-frequency vibration isolation performance. However, their insufficient structural compactness has always hindered their engineering application. These isolators require the integration of multiple core functional components, including permanent magnet arrays, electromagnetic excitation coils, stiffness adjustment mechanisms, and vibration sensing units. To avoid electromagnetic coupling interference and ensure uniform magnetic field distribution, necessary installation gaps and buffer spaces must be reserved between each component. Furthermore, traditional parallel spring configurations often increase the axial dimension of the isolator to meet the low-stiffness requirements for extension stroke, resulting in radial volume redundancy.

[0004] Furthermore, the stiffness adjustment capability of most current electromagnetic quasi-zero stiffness isolators is significantly limited, making it difficult to achieve continuous bidirectional switching between positive and negative stiffness. Existing designs often only allow for unidirectional fine-tuning within a fixed stiffness range, or only achieve a limited transition from positive stiffness to weak negative stiffness, failing to achieve bidirectional reversible conversion between positive and negative stiffness. This structural defect not only makes them unsuitable for applications with limited installation space, such as aerospace precision instruments and automotive electronic equipment, but also weakens their low-frequency vibration isolation advantages due to the increased inherent mass of the system, thus restricting the isolator's adaptive vibration isolation capability under complex and variable operating conditions.

[0005] Therefore, there is an urgent need for a bidirectional adjustable electromagnetic quasi-zero stiffness vibration isolation device and control method that can achieve bidirectional dynamic adjustment of stiffness and has a compact, non-contact structure. Summary of the Invention

[0006] The purpose of this invention is to provide a bidirectional adjustable electromagnetic quasi-zero stiffness vibration isolation device and control method, aiming to solve the technical problems of existing electromagnetic quasi-zero stiffness vibration isolators having a non-compact structure, limited unidirectional stiffness adjustment, and difficulty in bidirectional switching.

[0007] To achieve the above objectives, in a first aspect, the present invention provides a bidirectional adjustable electromagnetic quasi-zero stiffness vibration isolation device, comprising:

[0008] A fixed support frame, comprising an upper fixed plate and a lower fixed plate spaced apart vertically;

[0009] The suspended support frame is floating between an upper fixed plate and a lower fixed plate, and includes a horizontal support plate floating between the two fixed plates, a guide rod vertically mounted on the horizontal support plate, and a loading platform mounted on the top of the guide rod. The guide rod passes through the upper fixed plate so that the loading platform is located above the upper fixed plate.

[0010] The positive stiffness module includes a first disc motor assembly coaxially disposed on the lower surface of the upper fixed plate and the inner ring position of the upper surface of the lower fixed plate, and an annular permanent magnet disposed on the inner ring positions of the upper and lower surfaces of the horizontal support plate, for generating electromagnetic support force in the vertical direction and forming positive stiffness.

[0011] The negative stiffness module includes a second disc motor assembly coaxially disposed on the lower surface of the upper fixed plate and on the outer ring of the upper surface of the lower fixed plate, and an annular magnetic plate disposed on the outer ring of the upper and lower surfaces of the horizontal support plate, for generating electromagnetic attraction in the vertical direction and forming negative stiffness.

[0012] The positive stiffness module and the negative stiffness module are coaxially connected in parallel and act on the horizontal support plate. By independently adjusting the current of the positive and negative stiffness modules or adjusting the current of the positive and negative stiffness modules simultaneously, the quasi-zero stiffness of the vibration isolation system can be achieved.

[0013] As a further improvement to the above solution, the first disc motor assembly and the second disc motor assembly adopt a radially nested arrangement structure, so that the negative stiffness module covers the positive stiffness module in the radial direction, thereby achieving a compact overall structure.

[0014] As a further improvement to the above solution, the two first disc motor assemblies are arranged opposite each other, and the two annular permanent magnets are suspended between the two first disc motor assemblies through the horizontal support plate. The upper surface of the inner ring of the horizontal support plate is provided with a convex ring, and one annular permanent magnet is arranged on the upper surface of the convex ring so that the upper air gap and the lower air gap of the positive stiffness module are different in the initial state.

[0015] The two second disc motor assemblies are arranged vertically opposite each other, and the two annular magnetic plates are suspended between the two second disc motor assemblies through the horizontal support plate.

[0016] The inner diameter of the second disc motor assembly is larger than the outer diameter of the first disc motor assembly, and there is a preset interval in the radial direction.

[0017] As a further improvement to the above solution, the first disc motor assembly and the second disc motor assembly have the same structure, each including an annular stator core and a plurality of coil windings disposed on the annular stator core. Each coil winding unit is arranged in parallel and generates an axial magnetic field after each coil winding is energized, which is used to generate electromagnetic force with the annular permanent magnet or the annular magnetic guide plate.

[0018] As a further improvement to the above solution, in the positive stiffness module, the magnetic field generated by the first disc motor assembly interacts with the magnetic field of the ring permanent magnet to form a restoring force that increases with the increase of vertical displacement, so that the system exhibits positive stiffness characteristics.

[0019] In the negative stiffness module, the magnetic field generated by the second disc motor assembly forms an electromagnetic attraction with the annular magnetic plate, and the electromagnetic attraction exhibits negative stiffness characteristics as the vertical displacement changes.

[0020] As a further improvement to the above solution, this device also includes a controller, a force sensor, a current sensor, a displacement sensor, and an acceleration sensor.

[0021] The force sensor is mounted on the loading platform and is used to detect the load mass in real time.

[0022] The current sensor is installed in the power supply circuit of each disc motor assembly to detect the actual operating current of each disc motor assembly.

[0023] The displacement sensor and acceleration sensor are both mounted on the horizontal support plate and are used to detect the displacement and acceleration of the protected object, respectively.

[0024] The controller is connected to the force sensor, current sensor, displacement sensor and acceleration sensor respectively, and is used to adjust the current of each disc motor assembly according to load changes, current feedback and vibration signals.

[0025] As a further improvement to the above solution, the fixed support frame also includes several support columns, which are evenly arranged around the upper and lower fixed plates to form a stable external frame together with the upper and lower fixed plates.

[0026] The lower surface of the upper fixing plate and the upper surface of the lower fixing plate are provided with a number of locking blocks. Correspondingly, the bottom surface of each annular stator core is provided with a locking groove. Each disc motor assembly is positioned on the corresponding fixing plate through the locking groove and locking blocks, and then fixedly connected to the corresponding fixing plate by welding or other means.

[0027] As a further improvement to the above solution, the controller can synchronously adjust the current of the positive stiffness module and / or the negative stiffness module when the load increases or decreases, so as to achieve bidirectional dynamic adjustment of positive stiffness and negative stiffness and maintain the quasi-zero stiffness state of the vibration isolation device.

[0028] Secondly, the present invention also provides a control method for a bidirectional adjustable electromagnetic quasi-zero stiffness vibration isolation device as described in the first aspect, comprising the following steps:

[0029] S1. Initial current is supplied to each of the first disc motor components in the positive stiffness module to generate electromagnetic support force between the first disc motor component and the corresponding permanent magnet, so as to balance the gravity of the load on the platform and establish the initial static equilibrium state of the vibration isolation device.

[0030] An initial current is supplied to each of the second disc motor assemblies in the negative stiffness module, so that an electromagnetic attraction is formed between the second disc motor assembly and the corresponding annular magnetic plate, so that the system forms a negative stiffness characteristic near the static equilibrium state.

[0031] S2. Load change information on the load platform is collected in real time by force sensors installed on the load platform, and the load change information is transmitted to the controller. The controller adjusts the current of the disc motor assembly in the positive stiffness module and / or negative stiffness module respectively, so that the system always maintains a quasi-zero stiffness state under load changes.

[0032] As a further improvement to the above scheme, when an increase in load is detected, the current of the positive stiffness module is increased to enhance the supporting force, and / or the current of the negative stiffness module is increased so that the system still maintains quasi-zero stiffness.

[0033] When a decrease in load is detected, the current supplied to the positive stiffness module is reduced, and / or the current supplied to the negative stiffness module is reduced, so that the system returns to the quasi-zero stiffness operating point.

[0034] As a further improvement to the above solution, when the current sensor detects a deviation between the actual current of each disc motor component and the set current, the controller compensates for the deviation by adjusting the power supply voltage to maintain the quasi-zero stiffness state of the system.

[0035] Because the present invention adopts the above technical solutions, the beneficial effects of this application are as follows:

[0036] This invention provides a bidirectional adjustable electromagnetic quasi-zero stiffness vibration isolation device. Firstly, by coaxially connecting a positive stiffness module and a negative stiffness module in parallel on the upper and lower sides of the same horizontal support plate, and independently controlling their energizing current using first and second disc-type motor assemblies, this device breaks through the limitation of traditional vibration isolators having only one direction of stiffness adjustment. The positive stiffness module is supported by the electromagnetic repulsion between the first disc-type motor assembly and the ring-shaped permanent magnet, while the negative stiffness module cancels out the positive stiffness through the electromagnetic attraction between the second disc-type motor assembly and the ring-shaped magnetic plate. This parallel decoupling control allows the overall system stiffness to be dynamically adjusted bidirectionally over a wide range based on the actual load or environmental vibration characteristics, by independently adjusting the energizing current of the positive and negative stiffness modules or adjusting their energizing currents simultaneously.

[0037] Secondly, this invention employs a coaxial layout with nested inner and outer rings, arranging the components providing positive and negative stiffness at the inner and outer ring positions of the horizontal support plate, upper fixed plate, and lower fixed plate, respectively. This coaxial design avoids redundant stacking of multiple adjustment mechanisms, achieving complex bidirectional stiffness adjustment functions while maximizing the compression of the device's radial and axial dimensions, thus solving the problems of bulky structure and low integration in existing electromagnetic quasi-zero stiffness vibration isolators.

[0038] Furthermore, since both the positive and negative stiffness modules are based on electromagnetic force, their response speed is fast and their adjustability is strong. By adjusting the current in real time, the device can quickly compensate for positive stiffness when the weight of the platform changes, and precisely match negative stiffness to offset the residual stiffness of the system, allowing the system to maintain a near-zero stiffness operating point for a long time. This not only ensures effective isolation from ultra-low frequency vibrations, but also overcomes the technical defects of traditional mechanical near-zero stiffness mechanisms, which are extremely sensitive to initial loads and difficult to dynamically adjust.

[0039] In addition, the suspension support frame adopts a design where guide rods pass through the fixed plate. Combined with the electromagnetic components symmetrically arranged on the upper and lower parts of the horizontal support plate, it can ensure that the vertical movement trajectory of the suspension system is controlled, reduce lateral interference caused by eccentric loads, and enhance the reliability of the system in high-precision vibration isolation scenarios. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0041] Figure 1 This is a three-dimensional schematic diagram of a bidirectional adjustable electromagnetic quasi-zero stiffness vibration isolation device disclosed in this invention;

[0042] Figure 2 This is a three-dimensional cross-sectional schematic diagram of a bidirectional adjustable electromagnetic quasi-zero stiffness vibration isolation device disclosed in this invention.

[0043] Figure 3 This is a front sectional view of a bidirectional adjustable electromagnetic quasi-zero stiffness vibration isolation device (without fixed support frame) disclosed in this invention.

[0044] Figure 4 This is a three-dimensional schematic diagram of the fixed support frame disclosed in this invention;

[0045] Figure 5 This is a three-dimensional schematic diagram of the positive stiffness module disclosed in this invention;

[0046] Figure 6 This is a three-dimensional schematic diagram of the negative stiffness module disclosed in this invention;

[0047] Figure 7 This is a three-dimensional schematic diagram of the suspended support frame disclosed in this invention;

[0048] Figure 8 This is a schematic diagram of the control principle of a bidirectional adjustable electromagnetic quasi-zero stiffness vibration isolation device disclosed in this invention, which detects and compensates for the mismatch between positive and negative stiffness caused by coil damage.

[0049] Figure 9 This is a schematic diagram of the parallel connection of the coil windings of a bidirectional adjustable electromagnetic quasi-zero stiffness vibration isolation device disclosed in this invention.

[0050] Figure label:

[0051] 1. Fixed support frame; 11. Upper fixed plate; 12. Lower fixed plate; 13. Support column; 2. Suspended support frame; 21. Horizontal support plate; 22. Guide rod; 23. Loading platform; 3. Positive stiffness module; 31. First disc motor assembly; 32. Ring permanent magnet; 4. Negative stiffness module; 41. Second disc motor assembly; 42. Ring magnetic plate; 5. Ring stator core; 6. Coil winding.

[0052] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0053] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] It should be noted that all directional indicators (such as up, down, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0055] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.

[0056] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0057] Example 1

[0058] See Figures 1-7 The present invention provides a bidirectional adjustable electromagnetic quasi-zero stiffness vibration isolation device, including a fixed support frame 1, a suspended support frame 2, and a nested positive stiffness module 3 and a negative stiffness module 4.

[0059] The fixed support frame 1 forms an external frame through an upper fixed plate 11 and a lower fixed plate 12 that are spaced apart and arranged in parallel. The upper fixed plate 11 and the lower fixed plate 12 form a stable external frame through a number of support columns 13, and the number of support columns 13 are evenly arranged around the circumference of the fixed plate.

[0060] The suspended support frame 2, serving as the main body for vibration isolation, is vertically and flexibly positioned within the gap between the upper and lower fixed plates 12. It includes a horizontal support plate 21, a guide rod 22 vertically positioned on the upper surface of the horizontal support plate 21, and a loading platform 23 positioned at the top of the guide rod 22. The horizontal support plate 21 is placed within the space formed by the upper and lower fixed plates 12, and the top of the guide rod 22 passes through the upper fixed plate 11 so that the loading platform 23 is positioned directly above the upper fixed plate 11. This arrangement not only enables the vertical transmission of loads by the guide rod 22 passing through the upper fixed plate 11, but also ensures the axial stability of the suspension system during vertical floating by the limiting effect of the upper fixed plate 11 on the guide rod 22, effectively preventing horizontal swaying caused by eccentric loads.

[0061] The positive stiffness module 3 is located in the inner ring region of the device. Borrowing from the pressure difference mechanism of the upper and lower air chambers of a pneumatic spring, it transforms traditional pneumatic drive into electromagnetic control, achieving contactless positive stiffness output. Specifically, a first disc motor assembly 31 is installed on the lower surface of the inner ring of the upper fixed plate 11 and the upper surface of the inner ring of the lower fixed plate 12, respectively; correspondingly, annular permanent magnets 32 are arranged on the upper and lower surfaces of the inner ring of the horizontal support plate 21. During operation, different magnitudes of current are passed through the upper air gap d1 and the lower air gap d2, causing the upper and lower electromagnetic fields to interact with the permanent magnets and generate a vertical electromagnetic support force. That is, the gap between the first disc motor assembly 31 on the upper fixed plate 11 and the annular permanent magnet 32 ​​on the upper surface of the horizontal support plate 21 is the upper air gap d1; the gap between the second disc motor assembly 41 on the lower fixed plate 12 and the annular permanent magnet 32 ​​on the lower surface of the horizontal support plate 21 is the lower air gap d2. The electromagnetic support force not only balances the load on the platform 23, but also forms the system's reference positive stiffness due to the characteristic that the electromagnetic force changes with the air gap. This setup, by adjusting the magnetic field strength of the upper and lower air gaps through current differences, effectively simulates the contactless drive logic of the pressure difference between the upper and lower air chambers of a pneumatic spring, avoiding mechanical contact losses. By independently adjusting the current magnitude, different load weights can be compensated in real time, ensuring that the device is always in the optimal balance position.

[0062] The negative stiffness module 4 surrounds the positive stiffness module 3 in a coaxial nested arrangement. A second disc motor assembly 41 is mounted on the lower surface of the inner ring of the upper fixed plate 11 and the upper surface of the outer ring of the lower fixed plate 12, respectively. Grooves are provided on the upper surface of the outer ring of the horizontal support plate 21, and annular magnetic plates 42 are provided within these grooves. When energized, the second disc motor assembly 41 and the annular magnetic plate 42 generate an electromagnetic attraction. Since the direction of the attraction is the same as the direction of the displacement deviation, it exhibits a tendency to become unstable, thus introducing negative stiffness characteristics into the system. Unlike the negative stiffness generated by the tilted arrangement of traditional mechanical springs, the negative stiffness achieved through electromagnetic attraction in this embodiment does not involve mechanical friction, and the adjustment range is continuous, enabling more precise counteraction of the residual stiffness generated by the positive stiffness module 3.

[0063] The positive stiffness module 3 and the negative stiffness module 4 are arranged coaxially in the vertical direction and act in parallel on the horizontal support plate 21. By independently adjusting the current of the positive stiffness module 3 and the negative stiffness module 4, or by simultaneously adjusting the current of the positive and negative stiffness modules, the magnitudes of the positive stiffness and negative stiffness can be increased or decreased respectively. The system can switch bidirectionally between different states, such as positive stiffness being greater than negative stiffness, positive stiffness being less than negative stiffness, and the two canceling each other out. This enables bidirectional dynamic adjustment of the system stiffness over a wide range.

[0064] In actual operation, when an external stimulus is applied to the loading platform 23, the suspended support frame 2 will cause the horizontal support plate 21 to undergo vertical displacement. At this time:

[0065] The first disc motor assembly 31 generates a corresponding electromagnetic force according to the displacement of the horizontal support plate 21, forming a positive stiffness support to prevent the suspended support frame 2 from sinking or floating excessively.

[0066] At the same time, the horizontal support plate 21 is displaced relative to the second disc motor assembly 41 on both sides, generating an attractive force in the same direction as the displacement, thus creating a negative stiffness effect.

[0067] Positive stiffness and negative stiffness act in parallel in the vertical direction. Through reasonable design, they cancel each other out within a certain displacement range, achieving a near-zero stiffness equilibrium state, thereby effectively isolating external low-frequency vibrations.

[0068] Specifically, the current of the two disc motor assemblies is adjusted independently by the controller:

[0069] By adjusting the current of the positive stiffness module 3 and / or the negative stiffness module 4, when the adjusted current makes the positive stiffness and negative stiffness numerically equal and cancel each other out, the system enters a quasi-zero stiffness state. At this time, the device has an extremely low natural frequency, which can effectively isolate ultra-low frequency micro-vibrations. According to the operating conditions, such as active vibration suppression or rapid reset, the current of one of the modules can be dynamically increased or decreased to achieve quasi-zero stiffness of the vibration isolation system.

[0070] This coaxial nesting and independently adjustable method, while ensuring a compact structure, completely solves the technical shortcomings of traditional vibration isolators, such as limited stiffness adjustment range and difficulty in achieving bidirectional dynamic switching. The layout of the inner and outer rings makes full use of space, enabling this device to still have extremely strong nonlinear stiffness fitting capabilities while being miniaturized.

[0071] In a preferred embodiment, two first disc motor assemblies 31 are arranged vertically opposite each other, with their mounting references maintaining coaxiality to ensure symmetry in the magnetic field distribution. Two corresponding annular permanent magnets 32 are assembled and positioned via a horizontal support plate 21, and are suspended between the two first disc motor assemblies 31 by the magnetic field force generated by the first disc motor assemblies 31. The upper surface of the inner ring of the horizontal support plate 21 has a convex ring, and one of the annular permanent magnets 32 is disposed on the upper surface of the convex ring, so that the upper and lower air gaps of the positive stiffness module 3 are different in the initial state. This suspended arrangement effectively eliminates mechanical contact friction between the annular permanent magnet 32 ​​and the first disc motor assemblies 31, reducing component wear and energy loss due to friction. Furthermore, the horizontal support plate 21 provides a stable assembly carrier for the annular permanent magnet 32, ensuring structural posture consistency in the suspended state.

[0072] Correspondingly, this embodiment also includes two second disc motor assemblies 41, which are also vertically aligned and positioned opposite each other, with their installation positions coaxial with the first disc motor assembly 31. Two annular magnetic plates 42 are assembled via the same horizontal support plate 21 and, under the influence of the magnetic field generated by the second disc motor assemblies 41, are suspended between them. Similarly, the suspended arrangement of the annular magnetic plates 42 avoids mechanical friction with the second disc motor assemblies 41, extending the service life of the components. Furthermore, the coordinated assembly of the annular magnetic plates 42 and the horizontal support plate 21 works in conjunction with the suspended posture of the annular permanent magnet 32, improving the overall structural suspension stability.

[0073] Furthermore, in this embodiment, the inner diameter of the second disc motor assembly 41 is set to be larger than the outer diameter of the first disc motor assembly 31, and a preset interval is reserved between the two in the radial direction. This arrangement allows the first disc motor assembly 31 and the second disc motor assembly 41 to form a radially nested layout, effectively saving radial installation space and adapting to the miniaturization design requirements of the equipment; at the same time, the preset radial interval can avoid mutual interference caused by the superposition of magnetic fields during operation, ensuring the independence of their respective magnetic fields and operational stability, thereby ensuring the operating accuracy of the entire equipment.

[0074] In a preferred embodiment, the first disc motor assembly 31 and the second disc motor assembly 41 have the same structure, each including an annular stator core 5 and a plurality of coil windings 6 disposed on the annular stator core 5, wherein the coil windings 6 are connected in parallel. The annular stator core 5 is fixedly disposed on a corresponding fixed plate, and the coil windings 6 are evenly distributed circumferentially within the annular stator core 5 to generate an axial magnetic field when energized.

[0075] When current is applied to the coil winding 6 of the second disc motor assembly 41, according to the principle of electromagnetism, the coil winding 6 generates a constant axial magnetic field. This axial magnetic field acts on the annular magnetic plate, causing the magnetic induction intensity inside the annular magnetic plate to increase. Due to the existence of the magnetic field gradient, the magnetic plate is subjected to axial attraction and moves closer to the second disc motor assembly 41, which is manifested as an attraction force, thereby applying an electromagnetic attraction force to the suspension support frame 2.

[0076] When current is applied to the coil winding 6 of the first disc motor assembly 31, according to the principle of electromagnetism, the coil winding 6 will generate a stable axial magnetic field, causing the magnetic moment of the annular permanent magnet 32 ​​to interact with the magnetic field generated by the coil winding 6, thus generating an electromagnetic force. By reasonably designing the current direction of the annular stator core 5 winding and the magnetic pole direction of the annular permanent magnet 32 ​​in the disc motor assembly, the direction of the electromagnetic force can be controlled to make it exhibit a repulsive force, thereby applying an electromagnetic support force to the suspension support frame 2.

[0077] By adjusting the energizing current of the disc motor assembly, the amplitude of the electromagnetic force can be changed, causing the positive stiffness module 3 or the negative stiffness module 4 to exhibit different stiffness characteristics near the equilibrium position.

[0078] Because the coil windings 6 are connected in parallel, while ensuring sufficient axial magnetic field strength, it helps to reduce the operating voltage and current load of individual windings, improves the working stability and reliability of the disc motor assembly, and avoids affecting the overall performance of the vibration isolation device due to local winding overload. Simultaneously, the axial magnetic field's action allows the electromagnetic force to act directly on the horizontal support plate 21 in the vertical direction, facilitating a compact structural arrangement and reducing radial space occupation, thus meeting the structural requirements of this invention for a compact bidirectional adjustable electromagnetic quasi-zero stiffness vibration isolation device.

[0079] Furthermore, since the disc motor assembly and the annular permanent magnet 32 ​​or the annular magnetic guide plate 42 transmit force through non-contact electromagnetic interaction, friction and wear caused by mechanical contact can be effectively avoided, thereby improving the stability and service life of the vibration isolation device during long-term operation.

[0080] In a preferred embodiment, the positive stiffness module 3 and the negative stiffness module 4 are arranged coaxially in the vertical direction and act together on the horizontal support plate 21 of the suspension support frame 2 to adjust the equivalent stiffness characteristics of the vibration isolation device in the vertical direction.

[0081] The positive stiffness module 3 employs a structure in which a first disc motor assembly 31 and a ring-shaped permanent magnet 32 ​​cooperate. When energized, the first disc motor assembly 31 generates a magnetic field in its axial direction. This magnetic field interacts with the magnetic field of the ring-shaped permanent magnet 32, located within the inner ring of the horizontal support plate 21, forming an electromagnetic support force in the vertical direction. When the suspended support frame 2 undergoes vertical displacement relative to the fixed support frame 1, the relative air gap between the first disc motor assembly 31 and the ring-shaped permanent magnet 32 ​​changes accordingly, causing the electromagnetic support force to increase with the increase of vertical displacement, thereby forming a positive stiffness with restoring characteristics near the equilibrium position. In this way, a stable load-bearing capacity can be provided for the vibration isolation system without the need for the introduction of mechanical elastic elements.

[0082] The negative stiffness module 4 adopts a structure in which a second disc motor assembly 41 cooperates with an annular magnetic guide plate 42. When the second disc motor assembly 41 is energized, the magnetic field generated forms magnetic flux coupling with the annular magnetic guide plate 42 in the vertical direction, thereby generating an electromagnetic attraction force pointing towards the disc motor assembly. As the vertical displacement of the suspension support frame 2 changes, the magnetic circuit conditions between the disc motor assembly and the annular magnetic guide plate 42 change, causing the electromagnetic attraction force to exhibit a negative stiffness characteristic that varies with displacement near the equilibrium position. The introduction of this negative stiffness module 4 can effectively counteract part of the restoring force generated by the positive stiffness module 3, providing conditions for achieving a quasi-zero stiffness state.

[0083] By arranging the positive stiffness module 3 and the negative stiffness module 4 in parallel in the same structure and adjusting their energization states respectively, the system stiffness can be flexibly adjusted between positive stiffness, negative stiffness and quasi-zero stiffness states while maintaining the compact structure and non-contact operation of the device. This effectively solves the problem that the stiffness adjustment range of existing electromagnetic vibration isolation devices is limited and it is difficult to achieve bidirectional switching.

[0084] In a preferred embodiment, the device is also equipped with a controller, a force sensor, a current sensor, a displacement sensor, and an acceleration sensor.

[0085] Specifically, to ensure the stable operation of the vibration isolation device under varying load conditions, a force sensor (not shown in the figure) is installed on the loading platform 23 to detect changes in external load in real time. The force sensor employs a non-contact measurement method. The sensor signal output is connected to the controller to provide real-time displacement feedback information.

[0086] The controller receives real-time force signals from the force sensor and calculates the current load change based on these signals. According to the set control algorithm, the controller determines whether the actual stiffness state of the current system deviates from the quasi-zero stiffness point. If a deviation from the target equilibrium position is detected, the controller will adjust one or more of the following control parameters in real time:

[0087] Adjusting the power supply current of the two first disc motor assemblies 31 changes the electromagnetic force they generate, thereby adjusting the restoring force of the positive stiffness module 3.

[0088] Alternatively, the power supply current of the two second disc motor assemblies 41 can be adjusted to change the electromagnetic force they generate, thereby adjusting the attractive force of the negative stiffness module 4.

[0089] Alternatively, the current of two pairs of disc motor assemblies can be adjusted simultaneously to achieve coordinated control of positive and negative stiffness, enabling bidirectional adjustment.

[0090] Through the above control methods, the controller can dynamically compensate for stiffness deviations caused by external disturbances, load changes, or system parameter drift, so that the system always maintains or approaches the quasi-zero stiffness operating point, thereby improving the stability and reliability of vibration isolation effect.

[0091] During operation, when the suspended support frame 2 experiences vertical displacement due to external vibration, the force sensor captures the displacement signal in real time and transmits it to the controller. The controller calculates the required compensation current value based on its built-in control logic and adjusts the two pairs of disc motor assemblies via the drive circuit. By adding a force sensor and controller, and introducing a feedback-based current control mechanism, the adaptive capability and control accuracy of the vibration isolation device are further enhanced. This allows the vibration isolation system to dynamically adjust according to actual working conditions, improving its adaptability to different loads and excitation frequencies, making it particularly suitable for applications requiring high vibration isolation accuracy.

[0092] In this embodiment, a current sensor (not shown in the figure) is installed on each disc motor assembly to detect the current in the coil winding 6 of each disc motor assembly in real time. The current sensor employs various measurement methods, such as Hall effect current sensors or precision shunt resistors. The current sensor signal output is connected to a subsequent controller to provide real-time current feedback information.

[0093] The controller receives real-time current signals from the current sensor and calculates the current state of coil winding 6 based on these signals. According to the set control algorithm, the controller determines whether the actual current state of the current system deviates from the set current. If the actual current deviates from the set current, the controller will adjust the voltage source voltage in real time, thereby adjusting the restoring force of the positive stiffness module 3, or the attractive force of the negative stiffness module 4, or simultaneously adjusting the electromagnetic forces of the positive and negative stiffness modules, so that the positive and negative stiffness modules are rematched to maintain quasi-zero stiffness characteristics.

[0094] Through the above control methods, the controller can compensate for current deviations caused by coil damage, etc., so that the system always maintains or approaches the operating point of near-zero stiffness, thereby improving the stability and reliability of vibration isolation effect.

[0095] Both the displacement sensor and the acceleration sensor are mounted on the horizontal support plate 21. They are used to detect the displacement and acceleration signals of the protected object in real time, respectively. The displacement sensor can capture the vertical fluctuation of the object, while the acceleration sensor can sense the vibration intensity and motion trend. The two work together to collect vibration-related signals, providing the controller with comprehensive feedback on the object's motion state, avoiding the control blind spot caused by single parameter detection, and improving the vibration suppression capability of the vibration isolation device.

[0096] The controller establishes signal connections with force sensors, current sensors, displacement sensors, and acceleration sensors, respectively, and can synchronously receive load mass signals, operating current signals of each disc motor assembly, object displacement signals, and acceleration signals. Based on the load changes detected by the force sensors and the actual operating current feedback from the current sensors, the controller adjusts the energizing current of the disc motor assemblies in the positive stiffness module 3 and negative stiffness module 4. In this way, when the load increases or decreases, the energizing state of each disc motor assembly can be adjusted synchronously, allowing the system to re-establish balance under new load conditions and maintain the required stiffness characteristics. Simultaneously, closed-loop correction is performed based on current feedback and vibration signals to ensure precise matching between the output force of each disc motor assembly and the load and attitude control requirements, effectively improving the device's operating accuracy and anti-interference capability.

[0097] By introducing a collaborative working mechanism of force sensors, current sensors, displacement sensors, acceleration sensors, and controllers into the vibration isolation device, real-time sensing of load changes and effective adjustment of electromagnetic forces can be achieved without increasing the mechanical contact structure. This is beneficial to improving the adaptability and working stability of the vibration isolation device under different working conditions, thereby alleviating the problem of insensitive adjustment or insufficient stability of existing electromagnetic quasi-zero stiffness vibration isolation devices when the load changes.

[0098] In a preferred embodiment, the fixed support frame 1 further includes a plurality of support columns 13. Specifically, the plurality of support columns 13 are evenly arranged circumferentially along the upper fixed plate 11 and the lower fixed plate 12, and their two ends are respectively connected to the upper fixed plate 11 and the lower fixed plate 12, forming a stable external frame. The circumferentially evenly arranged design allows the supporting force to be evenly distributed along the circumference of the fixed plate, avoiding frame deformation caused by local force concentration, providing a stable installation reference for the upper and lower opposing disc motor assemblies, ensuring the symmetry of the magnetic field distribution of the motor assembly, and indirectly improving the operational stability of the suspension structure.

[0099] Furthermore, the lower surface of the upper fixing plate 11 and the upper surface of the lower fixing plate 12 are each provided with a plurality of locking blocks. Correspondingly, the bottom surface of the annular stator core 5 of each disc motor assembly is provided with a slot that matches the locking block. Each disc motor assembly is positioned and installed on the corresponding fixing plate through the cooperation of the slot and the locking block, and then connected to the corresponding fixing plate as a whole by welding or other methods. This assembly structure does not require complex fasteners, and can quickly realize the positioning and assembly of motor assemblies, improving assembly efficiency. At the same time, the matching cooperation of the locking block and the slot can limit the horizontal displacement of the motor assembly, prevent the motor assembly from shifting during operation, ensure the relative positional accuracy of the motor assembly and the suspended part, and thus improve the overall operational stability of the device.

[0100] In a preferred embodiment, the controller coordinates the operating states of the positive stiffness module 3 and the negative stiffness module 4 to maintain the quasi-zero stiffness characteristics of the vibration isolation device under varying load conditions. The controller is electrically connected to the disc motor assemblies of the positive stiffness module 3 and the negative stiffness module 4, respectively, and is used to adjust the energizing current of each disc motor assembly.

[0101] When the load on the loading platform 23 increases, the controller synchronously increases the current of the positive stiffness module 3 and / or the negative stiffness module 4 based on the load detection results. Specifically, by increasing the current of the positive stiffness module 3, the electromagnetic support force it generates increases accordingly to meet the load-bearing requirements of the new load; and / or, by synchronously adjusting the current of the negative stiffness module 4, its negative stiffness characteristics change accordingly, thereby maintaining a matching relationship between positive and negative stiffness near the new equilibrium position. This synchronous adjustment method avoids system stiffness deviation caused by adjusting only a single stiffness module.

[0102] When the load on the loading platform 23 decreases, the controller synchronously reduces the current of the positive stiffness module 3 and / or the negative stiffness module 4 according to the load change, so that the electromagnetic support force and electromagnetic attraction force decrease accordingly, thereby allowing the suspended support frame 2 to return to a new equilibrium position and maintain the matching relationship between positive stiffness and negative stiffness.

[0103] Specifically, when adjusting the energizing current of the positive stiffness module 3, the energizing current I1 of the first disc motor assembly 31, i.e., the first upper disc motor assembly, set on the upper fixed plate 11, is calculated according to the following formula:

[0104] ;

[0105] The current I2 of the first disc motor assembly 31, which is installed on the lower fixed plate 12, is calculated according to the following formula:

[0106] ;

[0107] When adjusting the energizing current of the negative stiffness module 4, the energizing current of the second disc motor assembly 41... The following formula is used to calculate:

[0108] ;

[0109] The upper air gap height is the positive stiffness. The air gap height under positive stiffness. δ represents the linear current density amplitude of the excitation coil of the second disc motor assembly 41, which is also the current carrying current of the second disc motor assembly 41; δ represents the height of the upper or lower air gap for negative stiffness (when quasi-zero stiffness is achieved, the upper and lower air gaps for negative stiffness are equal); and S represents the cross-sectional area of ​​the excitation coil. The number of turns of the positive stiffness coil. =1, harmonic coefficient; , These are the upper and lower Cartier coefficients for positive stiffness, respectively. The Cattell coefficient represents the negative stiffness. denoted as , where is the magnetic flux density of the toroidal permanent magnet 32. denoted by the perpendicular depth to the paper surface, where m is the load weight, and g is the acceleration due to gravity. Permeability of free space; The perpendicular depth to the paper surface is the negative stiffness, and p is the pole logarithm. is the polar moment, cosh is the hyperbolic cosine function, and sinh is the hyperbolic sine function.

[0110] Given that the structural parameters such as positive stiffness module 3, negative stiffness module 4, and external load are fixed, the excitation current required to achieve the quasi-zero stiffness state of the system can be calculated based on the above three formulas.

[0111] The controller can synchronously and bidirectionally adjust the current of the positive stiffness module 3 and the negative stiffness module 4 under different operating conditions of increased or decreased load, so that the overall stiffness of the system can be stably maintained in a quasi-zero stiffness state. This adjustment process does not rely on changes in the mechanical structure, but is achieved through current regulation, which helps to improve the adaptability and operational stability of the vibration isolation device to load changes, thereby alleviating the technical problems of the limited stiffness adjustment range and difficulty in achieving bidirectional stable adjustment of existing electromagnetic quasi-zero stiffness vibration isolation devices.

[0112] Example 2

[0113] This invention also provides a control method for a bidirectional adjustable electromagnetic quasi-zero stiffness vibration isolation device as described in Embodiment 1. The aim is to achieve precise regulation of the overall system stiffness and stable maintenance of the quasi-zero state through decoupling control of the currents in the positive and negative stiffness modules 4. This control method dynamically adjusts the currents in the first disc motor assembly 31 and / or the second disc motor assembly 41 through real-time monitoring and feedback control to ensure that the device maintains good vibration isolation performance under different load conditions. The steps include:

[0114] S1. Establish initial normal stiffness to stably support the load:

[0115] First, different initial currents are passed through the coil windings 6 of the two first disc motor assemblies 31, the first upper disc motor assembly and the first lower disc motor assembly with different air gap heights, respectively. Electromagnetic support forces are generated between the two first disc motor assemblies 31 and the corresponding annular permanent magnets 32, respectively generating an upward electromagnetic force F1 and a downward electromagnetic force F2, and F2 > F1. The load gravity mg is monitored by a force sensor to balance and the current is finely adjusted to F2 = F1 + mg to establish an initial positive stiffness to stably support the load.

[0116] Specifically, the change in load gravity mg is monitored in real time by a force sensor; based on the monitoring results, the current of coil winding 6 is adjusted until the balance condition F2=F1+mg is met.

[0117] At this point, the device establishes its initial positive stiffness, and the positive stiffness module 3, consisting of two first disc motor assemblies 31, two annular permanent magnets 32, and a horizontal support plate 21, begins to stably support the load, and the system enters a state of static equilibrium.

[0118] S2. Adjust the current to position the support plate at the center of the air gap:

[0119] After the positive stiffness is established, continue to adjust the coil current of the negative stiffness part so that the horizontal support plate 21 is at the center of the set air gap.

[0120] Specifically, the position of the horizontal support plate 21 when in equilibrium is monitored in real time using displacement sensors;

[0121] Based on the monitoring results, adjust the current amplitude until the horizontal support plate 21 is centered in the set air gap. At this point, the system's equilibrium position is at the set equilibrium position.

[0122] S3. Establish initial negative stiffness and maintain quasi-zero stiffness:

[0123] Once the positive stiffness is established, an initial current is supplied to the coil windings 6 of the two second disc motor assemblies 41, creating an electromagnetic attraction between the two second disc motor assemblies 41 and the annular magnetic plate 42, thus forming an initial negative stiffness. By introducing negative stiffness in the initial equilibrium state, part of the restoring force generated by the positive stiffness module 3 can be offset, thereby allowing the system to exhibit a lower equivalent stiffness near the equilibrium position, creating conditions for achieving a quasi-zero stiffness state.

[0124] S4. Real-time monitoring and dynamic adjustment to maintain near-zero stiffness:

[0125] During normal operation of the device, the vertical displacement x of the horizontal support plate 21 is acquired in real time by a displacement sensor, and the load change is acquired in real time by a force sensor. The two sensors feed back the acquired signals to the controller in real time.

[0126] The controller dynamically adjusts the current of the disc motor assembly based on the received displacement x and load information to maintain the quasi-zero stiffness state of the entire vibration isolation device.

[0127] The specific control strategy is as follows:

[0128] S31. When the load increases:

[0129] Positive stiffness adjustment: The controller increases the current in the coil winding 6 of the first disc motor assembly 31, thereby increasing the electromagnetic repulsion to support the new load;

[0130] Negative stiffness adjustment: and / or, increase the current of the second disc motor assembly 41, enhance the magnetic field effect, and increase the electromagnetic force of the negative stiffness module 4;

[0131] Through bidirectional adjustment, the positive stiffness module 3 and the negative stiffness module 4 work together to maintain the quasi-zero stiffness state of the system under new load conditions.

[0132] When the load decreases:

[0133] Stiffness adjustment: The controller reduces the current in the coil winding 6 of the first disc motor assembly 31, reduces the electromagnetic repulsion to accommodate the reduced load, and guides the vertical conductive support plate back to the static equilibrium position.

[0134] Negative stiffness adjustment: and / or, reduce the DC current of the second disc motor assembly 41, reduce the magnetic field strength, and reduce the electromagnetic force of the negative stiffness module 4;

[0135] Bidirectional adjustment function: Through bidirectional adjustment, it is ensured that the positive and negative stiffness modules 4 can still maintain a near-zero stiffness state together after the load is reduced.

[0136] The control method provided by this invention dynamically controls the balance between the positive stiffness electromagnetic force and the load gravity mg by adjusting the current in real time through the first disc motor assembly 31, thereby achieving on-demand adjustment of the positive stiffness. Combined with the current adjustment of the second disc motor assembly 41, it actively controls the electromagnetic force of the negative stiffness module 4. This bidirectional adjustment allows the device to maintain a quasi-zero stiffness state through current feedback adjustment when the load changes, thus solving the technical problem of the non-adjustable stiffness of traditional vibration isolation devices. This ensures that a quasi-zero stiffness state can be maintained under multiple operating conditions, effectively suppressing low-frequency vibrations and improving vibration isolation performance. The compact bidirectional adjustment structure decouples the positive and negative stiffness, adapting to different load ranges through independent current control. The electromagnetic effect of the negative stiffness module 4, due to the absence of mechanical contact, further reduces the system's natural frequency. Combined with the positive stiffness module 3, it effectively extends the vibration isolation frequency band, especially targeting low-frequency vibrations that are difficult to suppress by traditional devices. The real-time feedback from the displacement sensor and force sensor forms a dual closed-loop adjustment, and the accuracy of the current adjustment is directly related to the stiffness balance state. Compared to open-loop vibration isolators, this invention reduces stiffness drift caused by environmental interference and improves long-term operational reliability through a closed-loop link of sensor-controller-actuator (disc motor assembly).

[0137] In a preferred embodiment, to improve the stability of the vibration isolation device during operation, a current sensor is installed in the power supply circuit of each disc motor assembly to detect the actual operating current of the disc motor assembly in real time. The controller is pre-set with a target current value corresponding to the current operating state and uses this target current value as a reference for current adjustment.

[0138] See Figure 8 and Figure 9 When a coil winding 6 is damaged, and the current sensor detects a deviation between the actual current of the disc motor assembly and the target current value, the controller judges the deviation and compensates for it by adjusting the supply voltage of the disc motor assembly, so that the actual operating current approaches the target current value. By adjusting the supply voltage, the current output of the disc motor assembly can be stabilized without changing the structure of the vibration isolation device, thereby ensuring that the electromagnetic forces generated by the positive stiffness module 3 and the negative stiffness module 4 are within the expected range.

[0139] By using the above-mentioned current deviation detection and compensation methods, the influence of current deviation caused by factors such as power supply fluctuations, temperature rise, or load changes on electromagnetic force can be effectively reduced, and the matching relationship between positive stiffness and negative stiffness can be kept stable. This is beneficial for maintaining the quasi-zero stiffness state of the system near the equilibrium position during operation, thereby improving the operational reliability and long-term stability of the vibration isolation device.

[0140] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A bidirectional adjustable electromagnetic quasi-zero stiffness vibration isolation device, characterized in that, include: A fixed support frame, comprising an upper fixed plate and a lower fixed plate spaced apart vertically; The suspended support frame is floating between the upper and lower fixed plates and includes a horizontal support plate floating between the two fixed plates, a guide rod vertically mounted on the horizontal support plate, and a loading platform mounted on the top of the guide rod. The guide rod passes through the upper fixed plate so that the loading platform is located directly above the upper fixed plate. The positive stiffness module includes a first disc motor assembly coaxially disposed on the lower surface of the upper fixed plate and the inner ring position of the upper surface of the lower fixed plate, and an annular permanent magnet disposed on the inner ring positions of the upper and lower surfaces of the horizontal support plate, for generating electromagnetic support force in the vertical direction and forming positive stiffness. The negative stiffness module includes a second disc motor assembly coaxially disposed on the lower surface of the upper fixed plate and on the outer ring of the upper surface of the lower fixed plate, and an annular magnetic plate disposed on the outer ring of the upper and lower surfaces of the horizontal support plate, for generating electromagnetic attraction in the vertical direction and forming negative stiffness. The first disc motor assembly and the second disc motor assembly have the same structure, each including an annular stator core and a plurality of coil windings disposed on the annular stator core. Each coil winding unit is arranged in parallel and generates an axial magnetic field after each coil winding is energized, which is used to generate an electromagnetic force with the annular permanent magnet or the annular magnetic guide plate. The positive stiffness module and the negative stiffness module are coaxially connected in parallel and act on the horizontal support plate. By independently adjusting the current of the positive and negative stiffness modules or adjusting the current of the positive and negative stiffness modules simultaneously, the quasi-zero stiffness of the vibration isolation system can be achieved.

2. The bidirectional adjustable electromagnetic quasi-zero stiffness vibration isolation device according to claim 1, characterized in that, The first disc motor assembly and the second disc motor assembly adopt a radial nested arrangement structure, so that the negative stiffness module covers the positive stiffness module in the radial direction, thereby achieving a compact overall structure.

3. A bidirectional adjustable electromagnetic quasi-zero stiffness vibration isolation device according to claim 1 or 2, characterized in that, Two first disc motor assemblies are arranged opposite each other, and two annular permanent magnets are suspended between the two first disc motor assemblies through the horizontal support plate. The upper surface of the inner ring of the horizontal support plate is provided with a convex ring, and one annular permanent magnet is disposed on the upper surface of the convex ring. The two second disc motor assemblies are arranged vertically opposite each other, and the two annular magnetic plates are suspended between the two second disc motor assemblies through the horizontal support plate. The inner diameter of the second disc motor assembly is larger than the outer diameter of the first disc motor assembly, and there is a preset interval in the radial direction.

4. A bidirectional adjustable electromagnetic quasi-zero stiffness vibration isolation device according to claim 1 or 2, characterized in that, In the positive stiffness module, the magnetic field generated by the first disc motor assembly interacts with the magnetic field of the ring permanent magnet to form a restoring force that increases with the increase of vertical displacement, so that the system exhibits positive stiffness characteristics. In the negative stiffness module, the magnetic field generated by the second disc motor assembly forms an electromagnetic attraction with the annular magnetic plate, and the electromagnetic attraction exhibits negative stiffness characteristics as the vertical displacement changes.

5. The bidirectional adjustable electromagnetic quasi-zero stiffness vibration isolation device according to claim 1, characterized in that, The vibration isolation device also includes a controller, a force sensor, a current sensor, a displacement sensor, and an acceleration sensor; The force sensor is mounted on the loading platform and is used to detect the load mass in real time. The current sensor is installed in the power supply circuit of each disc motor assembly to detect the actual operating current of each disc motor assembly. The displacement sensor and acceleration sensor are both mounted on the horizontal support plate and are used to detect the displacement and acceleration of the protected object, respectively. The controller is connected to the force sensor, current sensor, displacement sensor and acceleration sensor respectively, and is used to adjust the current of each disc motor assembly according to load changes, current feedback and vibration signals.

6. The bidirectional adjustable electromagnetic quasi-zero stiffness vibration isolation device according to claim 1, characterized in that, The fixed support frame also includes several support columns, which are evenly arranged around the upper and lower fixed plates to form a stable external frame together with the upper and lower fixed plates. The lower surface of the upper fixing plate and the upper surface of the lower fixing plate are provided with a number of locking blocks. Correspondingly, the bottom surface of each annular stator core is provided with a locking groove. Each disc motor assembly is positioned on the corresponding fixing plate through the locking groove and the locking block.

7. A control method for a bidirectional adjustable electromagnetic quasi-zero stiffness vibration isolation device as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Initial current is supplied to each of the first disc motor components in the positive stiffness module to generate electromagnetic support force between the first disc motor component and the corresponding permanent magnet, so as to balance the gravity of the load on the loading platform and establish the initial static equilibrium state of the vibration isolation device. An initial current is supplied to each of the second disc motor assemblies in the negative stiffness module, so that an electromagnetic attraction is formed between the second disc motor assembly and the corresponding annular magnetic plate, so that the system forms a negative stiffness characteristic near the static equilibrium state. S2. Load change information on the load platform is collected in real time by force sensors installed on the load platform, and the load change information is transmitted to the controller. The controller adjusts the current of the disc motor assembly in the positive stiffness module and / or negative stiffness module respectively, so that the system always maintains a quasi-zero stiffness state under load changes.

8. The control method according to claim 7, characterized in that, When an increase in load is detected, the current supplied to the positive stiffness module is increased to enhance the supporting force, and / or the current supplied to the negative stiffness module is increased so that the system still maintains quasi-zero stiffness. When a decrease in load is detected, the current supplied to the positive stiffness module is reduced, and / or the current supplied to the negative stiffness module is reduced, so that the system returns to the quasi-zero stiffness operating point.

9. The control method according to claim 7, characterized in that, When the current sensor detects a deviation between the actual current of each disc motor component and the set current, the controller compensates for the deviation by adjusting the supply voltage to maintain the near-zero stiffness state of the system.

Images