Rigidity-adjustable active and passive composite shock absorber

Abstract

The invention relates to the technical field of vibration isolation and suppression devices, and discloses a rigidity-adjustable active and passive composite shock absorber. A load platform of the rigidity-adjustable active and passive composite shock absorber is located on the uppermost layer of the whole device; the supporting unit supports the active vibration reduction unit and the passive vibration reduction unit. The passive vibration reduction unit is matched with the active vibration reduction unit to form a second-order active and passive composite vibration reduction model, and the passive vibration reduction unit comprises a transverse groove type spring; the connecting unit comprises a connecting rod; the lower ends of the transverse groove type springs are connected with the supporting units, the upper ends of the transverse groove type springs support the load platform through connecting rods, and through holes are formed in the positions, corresponding to the connecting rods, of the transverse groove type springs. The fastener can penetrate through the load platform and the connecting rod to be screwed into the transverse groove type spring, and the rigidity of the transverse groove type spring is adjusted by adjusting the screwing-in depth of the fastener in the transverse groove type spring. In the active and passive composite shock absorber, compared with a traditional spring, the transverse groove type spring has the advantages of being compact and stable in structure, high in designability and the like, and the flexible rigidity requirement can be met through parametric design.

Description

Technical Field

[0001] The present application relates to the technical field of vibration isolation and suppression devices, for example, to an active and passive composite shock absorber with adjustable stiffness, which can be applied to equipment such as chariots, warships, aircraft and ships, and can also be used as auxiliary equipment on board. Background Art

[0002] The integration of electronic equipment is the key to promoting the transformation of equipment towards informatization, automation and intelligence. However, these electronic devices are often placed in extreme environments, such as tanks, ships, aircraft and ships. The various unstable conditions they face, such as ground bumps, wave impacts and high-altitude air flow disturbances, will cause strong vibrations and shocks. Therefore, vibration reduction technology is crucial to ensure the stable operation of equipment. Passive vibration reduction is good at medium and high frequency vibration reduction, but it is not effective in the low frequency band; on the contrary, active vibration reduction performs well in the low frequency band. In view of the limited space of shipborne and vehicle-borne equipment, the equipment is required to be miniaturized and lightweight. It is particularly important to design a broadband vibration reduction device with adjustable stiffness without changing the installation requirements, combining the advantages of active and passive vibration reduction.

[0003] Chinese patent CN114183493A proposes an active and passive vibration isolation rod and its control method, whose mechanism includes an electromagnetic damper, a cross-beam spring, a strain sensor, a flexible hinge, a piezoelectric actuator and a connecting rod. It has a certain effect on suppressing the micro-vibration of space optical loads, but there are problems such as unadjustable stiffness, limited control effect and large size.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present application, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0005] In order to provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. The summary is not an extensive review, nor is it intended to identify key / critical components or delineate the scope of protection of these embodiments, but rather serves as a prelude to the detailed description that follows.

[0006] The disclosed embodiments provide an active and passive composite shock absorber with adjustable stiffness. The device is miniaturized and lightweight, and combined with the advantages of active and passive vibration reduction, it can solve the problem of non-adjustable stiffness of the shock absorber without changing the installation requirements, and weaken the vibration of electronic equipment caused by impact on ships, aircraft and vessels in fluids, thereby preventing damage to shipborne electronic equipment due to excessive vibration.

[0007] In some embodiments, the active and passive composite vibration absorber with adjustable stiffness includes: a load platform, a support unit, a connection unit, an active vibration reduction unit and a passive vibration reduction unit;

[0008] The load platform is the top layer of the entire device and is used to carry equipment or objects that require vibration reduction; the support unit is used to support the active vibration reduction unit and the passive vibration reduction unit; the active vibration reduction unit is used to actively detect and adjust vibration to achieve active vibration isolation; the passive vibration reduction unit is used to cooperate with the active vibration reduction unit to form a second-order active and passive composite vibration reduction model, and the passive vibration reduction unit includes a transverse groove spring; the connecting unit is used to connect the load platform with the active vibration reduction unit and the passive vibration reduction unit, and the connecting unit includes a connecting rod; the lower end of the transverse groove spring is connected to the support unit, and the upper end supports the load platform through the connecting rod, and the corresponding parts of the transverse groove spring and the connecting rod are provided with through holes; the fastener can pass through the load platform and the connecting rod and be screwed into the transverse groove spring, and the stiffness of the transverse groove spring can be adjusted by adjusting the screw-in depth of the fastener in the transverse groove spring.

[0009] Optionally, the expression of the axial stiffness of the transverse groove spring is:

[0010]

[0011] Where E is the elastic modulus of the circular beam, a t is the radial wedge width, h is the layer beam thickness, n t is the total number of transverse groove spring layer beams, R 0 represents the radius of each layer of circular beam, μ is Poisson's ratio; γ is the section coefficient of the circular beam;

[0012] When the screw is screwed into the transverse groove spring layer beam, the axial stiffness is changed.

[0013] Optionally, the active vibration reduction unit includes a voice coil motor, a controller and an acceleration sensor; the output end of the acceleration sensor is connected to the input end of the controller, the output end of the controller is connected to the input end of the voice coil motor, and the voice coil motor, controller and acceleration sensor together constitute a closed-loop control system; the acceleration sensor collects signals, which are processed by the controller, and the voice coil motor actuator outputs an actuating force to offset residual vibration, and together with the passive vibration reduction unit constitute an active and passive composite vibration isolation mechanism.

[0014] Optionally, the controller adopts an integral force (IFF) feedback control law based on the ceiling damping technology, and its frequency domain form can be expressed as:

[0015]

[0016] In the formula, F P Represents the force signal of the load platform, C FP It is expressed as the feedback control rate, s is the complex variable of Laplace complex transform, which is used for frequency domain analysis, and x 0 represents the original vibration excitation of the base platform, M P is the load mass, Λ is the gain coefficient of the ceiling damping, k i =MP ·Λ is the integral gain coefficient of IFF feedback control.

[0017] Optionally, the support unit includes an upper outer cylinder and a middle cylinder coaxially arranged.

[0018] The upper outer tube is matched with the middle tube structure, the upper outer tube is sleeved on the outside of the middle tube, and the top is open;

[0019] A mounting groove is arranged in the middle of the middle tube, and a blind hole is arranged on the outer periphery of the middle tube.

[0020] Optionally, the connection unit further includes a flexible hinge and an output plate;

[0021] The output plate includes a table top and a bent beam. A boss is arranged at the center of the table top. A plurality of bent beams extend from the periphery of the table top. The bent beam is an L-shaped structure. The horizontal plate of the bent beam passes through the slots arranged on the side walls of the middle cylinder and the upper outer cylinder, and is connected to the load platform through a flexible hinge.

[0022] Optionally, the passive vibration reduction unit further includes a diaphragm spring and a magnetic damping device.

[0023] The diaphragm spring is located on the upper part of the transverse groove spring, the center of the diaphragm spring is connected and fixed to the boss of the output plate through a fastener, and the outer periphery is pressed by the upper outer cylinder and the middle cylinder;

[0024] The magnetic damping device is located below the bent beam transverse plate and is gap-matched with the blind hole of the middle tube.

[0025] Optionally, the diaphragm spring and the output plate are provided with through holes that match the positions.

[0026] One end of the connecting rod is connected to the load platform, and the other end passes through the through hole and is connected to the upper end of the transverse groove spring.

[0027] Optionally, the stator of the voice coil motor is fixed in the middle cylinder, and the mover is connected to the output plate;

[0028] The transverse groove spring is sleeved on the outside of the voice coil motor, and the lower end is connected and fixed to the middle tube.

[0029] Optionally, the outer ring of the upper outer cylinder is surrounded by an oil pressure buffer and the magnetic damping device.

[0030] The active and passive composite shock absorber with adjustable stiffness provided in the embodiments of the present disclosure can achieve the following technical effects:

[0031] The passive vibration reduction unit and the active vibration reduction unit in the active and passive composite vibration reduction device disclosed in the present invention cooperate to form a second-order active and passive composite vibration reduction model, which can reduce the natural frequency and resonance peak value of the system, while ensuring high attenuation of high-frequency vibrations, and realizing vibration isolation and noise reduction in a wider frequency band.

[0032] In addition, the opening of the transverse groove spring at the corresponding position of the connecting rod is a through hole. The stiffness of the transverse groove spring can be adjusted by adjusting the depth of the bolt screwed into the transverse groove spring to match the actual stiffness requirements.

[0033] Compared with traditional springs, the transverse groove spring disclosed in the present invention has the characteristics of compact structure, stability and strong design, and can realize flexible stiffness requirements through parametric design.

[0034] The active and passive composite shock absorber disclosed in the present invention can be used as a shipborne auxiliary equipment. The equipment is miniaturized and lightweight, and combined with the advantages of active and passive vibration reduction, it can weaken the vibration of electronic equipment caused by impact on ships, aircraft and vessels in fluids without changing the installation requirements, thereby effectively preventing damage to shipborne electronic equipment due to excessive vibration.

[0035] The above general description and the following description are exemplary and explanatory only and are not intended to limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] One or more embodiments are exemplarily described by corresponding drawings, which do not limit the embodiments. Elements with the same reference numerals in the drawings are shown as similar elements, and the drawings do not constitute a scale limitation, and wherein:

[0037] Figure 1 It is a schematic diagram of the explosion structure of the present invention;

[0038] Figure 2 A three-dimensional structural view of the present invention;

[0039] Figure 3 is a cross-sectional view of the present invention;

[0040] Figure 4 It is a schematic diagram of the passive support part of the present invention;

[0041] Figure 5 It is the active part structure of the present invention;

[0042] Figure 6 It is a cross-sectional view of the structure of the magnetic damping device of the present invention;

[0043] Figure 7 The flexible hinge structure of the present invention;

[0044] Figure 8 The diaphragm spring structure of the present invention;

[0045] Fig. 9 The groove spring structure of the present invention;

[0046] FIG10( a ) is a schematic diagram of the principle of a conventional passive vibration isolation mechanism;

[0047] FIG10( b ) is a schematic diagram of the active and passive composite vibration isolation mechanism of the present invention;

[0048] Fig.11 It is a comparison diagram of the transmissibility curves of the traditional passive vibration isolation platform and the present invention in passive and active-passive composite situations.

[0049] Reference numerals:

[0050] 1. Load platform; 2. Connecting rod; 3. Horizontal groove spring; 4. Diaphragm spring; 5. Flexible hinge; 6. Voice coil motor; 7. Output plate; 8. Magnetic damping device; 9. Oil pressure buffer; 10. Upper outer cylinder; 11. Middle cylinder; 12. Acceleration sensor; 13. Controller. DETAILED DESCRIPTION

[0051] In order to be able to understand the features and technical contents of the embodiments of the present disclosure in more detail, the implementation of the embodiments of the present disclosure is described in detail below in conjunction with the accompanying drawings. The attached drawings are for reference only and are not used to limit the embodiments of the present disclosure. In the following technical description, for the convenience of explanation, a full understanding of the disclosed embodiments is provided through multiple details. However, one or more embodiments can still be implemented without these details. In other cases, to simplify the drawings, well-known structures and devices can be simplified for display.

[0052] The terms "first", "second", etc. in the embodiments of the present disclosure are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged where appropriate, so as to describe the embodiments of the present disclosure described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0053] In the embodiments of the present disclosure, the terms "upper", "lower", "inside", "middle", "outside", "front", "back", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. These terms are mainly intended to better describe the embodiments of the present disclosure and their embodiments, and are not intended to limit the indicated devices, elements, or components to have specific directions, or to be constructed and operated in specific directions. Moreover, in addition to being used to indicate directions or positional relationships, some of the above terms may also be used to indicate other meanings. For example, the term "upper" may also be used to indicate a certain dependency or connection relationship in certain circumstances. For those of ordinary skill in the art, the specific meanings of these terms in the embodiments of the present disclosure can be understood according to specific circumstances.

[0054] In addition, the terms "disposed", "connected" and "fixed" should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements or components. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present disclosure can be understood according to the specific circumstances.

[0055] Unless otherwise stated, the term "plurality" means two or more.

[0056] In the embodiment of the present disclosure, the character " / " indicates that the preceding and following objects are in an "or" relationship. For example, A / B indicates: A or B.

[0057] The term "and / or" is a description of the association relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or, A and B.

[0058] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present disclosure may be combined with each other.

[0059] Combination Figure 1-5 As shown, an embodiment of the present disclosure provides an active and passive composite shock absorber with adjustable stiffness. The active and passive composite shock absorber is a columnar structure, including a load platform 1, a support unit, a connection unit, an active vibration reduction unit and a passive vibration reduction unit.

[0060] The load platform 1 is the uppermost layer of the entire device and is used to carry equipment or objects that require vibration reduction.

[0061] The support unit is used to support the load platform 1 , the active vibration reduction unit and the passive vibration reduction unit, and comprises an upper outer cylinder 10 and a middle cylinder 11 which are coaxially arranged.

[0062] The connection unit is used to connect the load platform 1 with the active vibration reduction unit and the passive vibration reduction unit, and includes a connection rod 2 , a flexible hinge 5 and an output plate 7 .

[0063] The active vibration reduction unit is used to actively detect and adjust vibration to achieve active vibration isolation, and includes a voice coil motor 6 , a controller 13 and an acceleration sensor 12 .

[0064] The passive vibration reduction unit includes a diaphragm spring 4, a transverse groove spring 3 and a magnetic damping device 8, which is used to cooperate with the active vibration reduction unit to provide additional damping and supporting force to further reduce vibration.

[0065] Regarding the support unit, Figures 1 to 3As shown, the upper outer cylinder 10 and the middle cylinder 11 are structurally matched, and the upper outer cylinder 10 is sleeved on the upper outer part of the middle cylinder 11, and the top is open. The connection between the middle cylinder 11 and the upper outer cylinder 10 is connected by 8 axisymmetric array 40° bolts, and the outer ring of the upper outer cylinder 10 is equipped with an oil buffer 9 and a magnetic damping device 8. The middle part of the middle cylinder 11 is provided with a mounting groove for installing the voice coil motor 6 and the transverse groove spring 3, and the outer periphery of the middle cylinder 11 is provided with a blind hole for placing the magnetic damping device 8, and the magnetic damping device 8 can be matched with the blind hole gap.

[0066] The mounting groove includes a first mounting groove for mounting the voice coil motor 6 and a second mounting groove for mounting the transverse groove spring 3. The second mounting groove is arranged around the first mounting groove so that the transverse groove spring 3 is sleeved outside the voice coil motor 6 and is arranged coaxially with the voice coil motor 6, so that the passive vibration reduction loop does not interfere with the active vibration reduction loop, and the installation space is greatly saved, so that the structure of the entire suspension system is simple and compact.

[0067] Regarding the output board 7, as Figures 1 to 3 As shown, the output plate 7 includes a table and a bent beam. A boss is provided at the center of the table for connecting with the diaphragm spring 4. A plurality of bent beams extend from the periphery of the table. The bent beam is an L-shaped structure. The horizontal plate of the bent beam passes through the slots provided on the side walls of the middle cylinder 11 and the upper outer cylinder 10, and is connected to the load platform 1 through the flexible hinge 5. The magnetic damping device 8 is located below the horizontal plate of the bent beam and is gap-matched with the blind hole of the middle cylinder 11.

[0068] The lower end of the stator of the voice coil motor 6 is fixed in the first mounting groove of the middle cylinder 11 by a fastener, and the mover of the voice coil motor 6 is connected to the platform of the output plate 7 .

[0069] Regarding passive vibration reduction units, such as Figure 1 , 3 As shown in , 4 and 8, the diaphragm spring 4 and the output plate 7 are provided with through holes that match the positions, one end of the connecting rod 2 is connected to the load platform 1, and the other end passes through the through hole and connects with the upper end of the transverse groove spring 3. The lower end of the transverse groove spring 3 is installed on the middle cylinder 11 through four countersunk bolts, and the upper end supports the load platform 1 through the connecting rod 2.

[0070] The center of the diaphragm spring 4 is fixed to the boss of the output plate 7 by bolts, and the outer periphery is compressed by the upper outer cylinder 10 and the middle cylinder 11 to save the height of the shock absorber.

[0071] like Figure 6 As shown, each magnetic damping device includes an annular permanent magnet 8b, each permanent magnet 8b is coaxially connected to the upper guide column 8a and the lower guide column 8c, a countersunk screw hole is provided between the lower end surface of the column 8d and the lower guide column 8c, and an interference fit is formed between the column 8d and the screw hole.

[0072] Regarding the active vibration reduction unit, the output end of the acceleration sensor 12 is connected to the input end of the controller 13, and the output end of the controller 13 is connected to the input end of the voice coil motor 6. The voice coil motor 6, the controller 13 and the acceleration sensor 12 together constitute a closed-loop control system.

[0073] The acceleration sensor 12 detects the vibration signal, and the controller 13 adjusts the output of the voice coil motor 6 according to the vibration signal. The transmission path of the active motion power output by the voice coil motor 6 is from the output plate 7 to the flexible hinge 5 and then to the load platform 1, thereby realizing active vibration isolation.

[0074] The transverse groove spring 3 which plays a supporting role is connected in parallel with the voice coil motor 6 which plays an active vibration control role, forming a typical second-order active-passive composite vibration reduction model, which can reduce the natural frequency and resonance peak value of the system, while ensuring high attenuation of high-frequency vibration, and realizing vibration isolation and noise reduction in a wider bandwidth.

[0075] In addition, the flexible hinge 5 has high axial stiffness and low bending stiffness, while the diaphragm spring 4 has low axial stiffness and high stiffness in other directions. The combined use of the two can effectively ensure the coaxiality of the stator and mover of the voice coil motor 6 and reduce the loss of motor output force, thereby enhancing the active vibration control capability and service life of the voice coil motor 6, while compensating for the displacement in other directions.

[0076] like Fig. 9 As shown, the opening of the transverse groove spring 3 at the corresponding position of the connecting rod 2 is a through hole, and the stiffness of the transverse groove spring 3 can be adjusted by adjusting the depth of the bolt screwed into the transverse groove spring 3 to match the actual stiffness requirement.

[0077] Compared with traditional springs, the transverse groove spring 3 has the characteristics of compact structure, stability and strong design, and can achieve flexible stiffness requirements through parametric design. The expression of the axial stiffness of the transverse groove spring is:

[0078]

[0079] Where E is the elastic modulus of the circular beam, and the radial wedge width a is t , layer beam thickness h, n t is the total number of transverse groove spring layer beams, R 0 It represents the radius of each layer of circular beam, μ is Poisson's ratio, and γ is the section modulus of the circular beam. When the screw is screwed into the three-layer beam of the transverse groove spring, the axial stiffness changes.

[0080] When the external vibration excitation signal is transmitted to the transverse groove spring at the center of the upper shell through the middle tube 11, the transverse groove spring has the characteristic of adjustable stiffness, and the stiffness is adjusted according to actual needs to change the natural frequency. Since the passive vibration isolation structure cannot change the vibration isolation performance at low frequencies, the remaining vibration response signal is collected by the acceleration sensor 12 connected to the load platform 1 and transmitted to the controller 13. After being processed by the IFF control algorithm, a corresponding control signal is generated, and then the voice coil motor 6 actuator is controlled to generate an actuating force, which offsets the residual vibration energy on the load platform 1, forming an active closed-loop feedback control, and realizing the ceiling damping effect, that is, effectively reducing the amplitude of the resonance peak at the natural frequency, and being able to ensure high-frequency high-attenuation vibration reduction performance.

[0081] As shown in Figure 10(a), the traditional passive vibration isolation platform can be composed of a mass-spring-damper unit, and its transfer function is:

[0082]

[0083] In the formula, x 1 is the displacement response of the load platform vibration, x 0 is the original vibration excitation of the base platform, the mass M of the load platform, C is the equivalent damping of the whole system, and K is the equivalent stiffness between the load platform and the base platform. These parameters act together in the vibration transmission process, where x 1 and x 0 The relationship between is expressed in the complex domain by Laplace transform, with s as the complex variable of the transform, so that the analysis can be performed in the frequency domain.

[0084] As shown in FIG10( b ), based on the traditional passive vibration isolation mechanism, the present invention makes it easy to change the stiffness of the passive elastic element. Without changing the actual application requirements of the vibration isolator, the stiffness is adjusted by adjusting the screwing depth of the bolt in the connecting rod 2, and an active feedback control loop is added. In the active feedback control loop, the acceleration sensor 12 collects the signal, which is processed by the controller 13, and the voice coil motor 6 actuator outputs the actuating force to offset the residual vibration, thereby forming an active and passive composite vibration isolation mechanism.

[0085] The passive elastic element in this embodiment is a grooved metal spring 3. The controller 13 adopts integral force feedback control.

[0086] The control algorithm adopts the integral force (IFF) feedback control law based on the ceiling damping technology, and its frequency domain form can be expressed as:

[0087]

[0088] In the formula, F P Represents the force signal of the load platform, C FPIt is expressed as the feedback control rate, s is the complex variable of Laplace complex transform, which is used for frequency domain analysis, and x 0 represents the original vibration excitation of the base platform, M P is the load mass, Λ is the gain coefficient of the ceiling damping, k i =M P ·Λ is the integral gain coefficient of IFF feedback control.

[0089] Fig.11 The transmissibility curves of the traditional passive vibration isolation system and the improved solution of the present invention under closed-loop control conditions are shown, with the horizontal axis representing frequency (Hz) and the vertical axis representing amplitude (dB). The solid line in the figure represents the transmissibility of the traditional passive vibration isolation, which is higher at the low-frequency resonance peak and has a higher natural frequency. The dotted line shows that the present invention adjusts the stiffness by adding a slotted spring 3, and changes the damping by adjusting the number of annular permanent magnets 8b and the upper and lower magnetic spacing, so that the resonance frequency moves forward and the resonance peak value is reduced. The dotted line shows that when combined with active control technologies such as IFF feedback, the transmissibility curve of the system changes further, the natural frequency moves forward further, and the resonance peak value is improved, which broadens the vibration isolation bandwidth and thus improves the vibration suppression capability.

[0090] Preferably, an oil pressure buffer 9 is arranged on the outer ring of the shock absorber, which can provide greater damping. Together with the flexible hinge 5, it can effectively prevent external impact from damaging the structure. The magnetic damping device 8 provides unidirectional damping for the equipment, improving high-frequency vibration isolation attenuation without affecting the main power of the voice coil motor 6.

[0091] Preferably, the load platform is evenly hollowed out in the middle, for example, cylindrical hollow grooves or discontinuous hollow ring grooves are provided around the middle, so as to reduce the weight while ensuring the rigidity and strength of the structure.

[0092] As an example, the active and passive composite shock absorber has an overall cylindrical shape with a height of 90 mm and a maximum diameter of 130 mm, so as to meet the height dimension requirements of the shock absorber.

[0093] Flexible hinges all adopt a bidirectional rounded straight beam structure, and their rotational stiffness is much smaller than that in other directions, and they are assumed to be rigid bodies in the axial direction. Compared with spherical hinges, flexible hinges overcome the shortcomings of gaps and friction between their kinematic pairs, thus overcoming the phase difference and insufficient stroke caused by the gap, as well as the additional damping caused by friction. The introduction of this damping increases the equivalent damping of the system, which reduces the high-frequency vibration reduction performance of the system.

[0094] When the magnetic damping device is subjected to external excitation, the annular permanent magnet 8b installed on the upper guide post 8a and the column barrel 8d move relative to each other, and this action immediately causes the change of the magnetic flux inside the column sleeve 8d, and an induced current is generated inside the column sleeve 8d, which is then converted into heat energy, effectively dissipating energy and providing damping force for the stable operation of the system; to ensure that there is no X-direction displacement of the vibration isolation and suppression device between the upper guide post 8a and the lower guide post 8c, and to avoid unnecessary harmful low-frequency resonance, the gap between the diameter of the middle section of the upper guide post 8a and the inner hole of the column barrel 8d is very small. In addition, to prevent the annular permanent magnet 8b of the upper guide post 8a from colliding relative to the annular permanent magnet 8b of the lower guide post 8c during operation and to maintain the unidirectional damping characteristics, the magnetic poles of the upper and lower permanent magnets 8b are in opposite directions.

[0095] As an example, a stiffness-adjustable active and passive composite shock absorber is provided, which includes, from top to bottom, a load platform 1, a connecting rod 2, a transverse groove spring 3, a diaphragm spring 4, a flexible hinge 5, a voice coil motor 6, an output plate 7, a magnetic damping device 8, an oil pressure buffer 9, an upper outer cylinder 10 and a middle cylinder 11, an acceleration sensor 12 and a controller 13;

[0096] The voice coil motor 6, acceleration sensor 12 and controller 13 are used to actively detect and adjust vibration to achieve active vibration isolation. The output end of the acceleration sensor 12 is connected to the input end of the controller 13, and the output end of the controller 13 is connected to the input end of the voice coil motor 6, together forming a closed-loop control system; the passive vibration reduction unit of the mechanism is composed of a diaphragm spring 4, a transverse groove spring 3 and a magnetic damping device 8.

[0097] like Figure 4 As shown, the lower end of the transverse groove spring 3 is installed at the center of the middle cylinder 11 through four countersunk bolts, and the upper end supports the load platform 1 through four connecting rods 2, and the connecting rods 2 pass through the openings of the diaphragm spring 4 and the output plate 7.

[0098] like Figure 5 As shown, the output plate 7 extends four bent beams 7b in all directions, and is connected to the load platform 1 through four flexible hinges 5 after passing through the slots of the upper outer cylinder 10 and the middle cylinder 11. The magnetic damping device 8 is installed under the bent beam 7b and fits with the blind hole gap of the middle cylinder 11.

[0099] The lower end of the voice coil motor stator 6a is fixed in the middle cylinder 11 by bolts, the voice coil motor mover 6b is connected to the output plate 7 by bolts, the central boss of the output plate 7 and the center of the diaphragm spring 4 are fixed by bolts, and the outer periphery of the diaphragm spring 4 is pressed tightly by the upper outer cylinder 10 and the middle cylinder 11 to meet the height of the shock absorber.

[0100] The connection between the middle cylinder 11 and the upper outer cylinder 10 is achieved through eight axially symmetrical arrays of 40° bolts. The outer ring of the upper outer cylinder 10 is surrounded by an oil pressure buffer 9 and a magnetic damping device 8 .

[0101] like Figure 6 As shown, each magnetic damping device 8 includes an annular permanent magnet 8b, each permanent magnet 8b is coaxially connected to the upper guide column 8a and the lower guide column 8c, a countersunk screw hole is provided between the lower end surface of the column barrel 8d and the lower guide column 8c, and an interference fit is formed between the column barrel 8d and the screw hole.

[0102] The transmission path of the active driving force output by the voice coil motor 6 is from the output plate 7 to the flexible hinge 5 and then to the load platform 1. The transverse groove spring 3, which plays a supporting role, is arranged in parallel with the voice coil motor 6, which plays an active vibration control role, to form a typical second-order active-passive composite vibration reduction model, which can reduce the natural frequency and resonance peak value of the system, while ensuring high attenuation of high-frequency vibration, and realizing vibration isolation and noise reduction in a wider frequency band.

[0103] like Figure 7-8 As shown, the flexible hinge 5 has high axial stiffness and low bending stiffness, while the diaphragm spring 4 has low axial stiffness and high stiffness in other directions. The combined use of the two can effectively ensure the coaxiality of the voice coil motor stator 6a and the mover 6b and reduce the loss of the motor output force, thereby enhancing the active vibration control capability and service life of the voice coil motor 6, while compensating for the displacement in other directions.

[0104] The opening of the transverse groove spring 3 at the corresponding position of the connecting rod 2 is a through hole, and the stiffness of the spring can be adjusted by adjusting the depth of the bolt screwed into the spring to match the actual stiffness requirement.

[0105] The outer ring of the shock absorber is arranged with an oil pressure buffer 9, which can provide greater damping. Together with the flexible hinge 5, it can effectively prevent external impact from damaging the structure. The magnetic damping device 8 provides unidirectional damping for the equipment, improving high-frequency vibration isolation attenuation without affecting the main power of the voice coil motor 6.

[0106] The load platform 1 is provided with a hollow annular ring and a cylindrical slot around the middle so as to be lightweight while ensuring structural rigidity and strength.

[0107] The grooved spring 3 is sleeved on the outside of the voice coil motor 6 to ensure that the passive vibration reduction loop does not interfere with the active vibration reduction loop, thereby greatly saving installation space and making the entire suspension system simple and compact.

[0108] The magnetic damping device 8, when external excitation acts, the annular permanent magnet 8b (installed on the upper guide column 8a) and the column barrel 8d move relative to each other, and this action immediately causes the change of the magnetic flux inside the column sleeve 8d, and generates an induced current inside the column sleeve 8d, which is then converted into heat energy, effectively dissipating energy, and providing damping force for the stable operation of the system; to ensure that there is no displacement in the X and Y directions between the upper guide column 8a and the lower guide column 8c, and to avoid unnecessary harmful low-frequency resonance, the gap between the diameter of the middle section of the upper guide column 8a and the inner hole of the column barrel 8d is very small. In addition, in order to prevent the annular permanent magnet 8b of the upper guide column 8a and the annular permanent magnet 8b of the lower guide column 8c from colliding relative to each other during operation, and to maintain the unidirectional damping characteristics, the magnetic poles of the upper and lower permanent magnets 8b are in opposite directions.

[0109] In this embodiment, Fig. 9 As shown, compared with the traditional spring, the transverse groove spring 3 has the characteristics of compact structure, stability and strong design, and can achieve flexible stiffness requirements through parametric design. The expression of the axial stiffness of the transverse groove spring is:

[0110]

[0111] Where E is the elastic modulus of the circular beam, and the radial wedge width a is t , layer beam thickness h, n t is the total number of transverse groove spring layer beams, R 0 It represents the radius of each layer of circular beam, μ is Poisson's ratio, and γ is the section modulus of the circular beam. When the screw is screwed into the three-layer beam of the transverse groove spring, the axial stiffness changes.

[0112] Combine the following Figures 1 to 10(b) The active and passive composite vibration absorber disclosed in the present invention will be described.

[0113] The present disclosure provides a vibration suppression platform, which is composed of a load platform 1, a connecting rod 2, a transverse groove spring 3, a diaphragm spring 4, a flexible hinge 5, a voice coil motor 6, a motor power output plate 7, a hydraulic buffer 9, a magnetic damping device 8, a middle cylinder 11, an upper outer cylinder 10 and an acceleration sensor 12, etc., and serves as an active and passive composite shock absorber with adjustable stiffness to weaken the vibration of electronic equipment caused by impact on ships, aircraft and ships in fluids, thereby preventing damage to ship-borne electronic equipment due to excessive vibration.

[0114] The load platform 1 is the top layer of the entire device and is used to carry equipment or objects that need vibration reduction. The coaxially arranged upper outer cylinder 10 and middle cylinder 11 serve as support units for supporting the load platform 1, the active vibration reduction unit and the passive vibration reduction unit. The active vibration reduction unit is used to actively detect and adjust vibration to achieve active vibration isolation, and includes a voice coil motor 6, a controller 13 and an acceleration sensor 12. The passive vibration reduction unit includes a diaphragm spring 4, a transverse groove spring 3 and a magnetic damping device 8, which are used to cooperate with the active vibration reduction unit to provide additional damping and support force to further reduce vibration.

[0115] The upper outer cylinder 10 is matched with the middle cylinder 11 in structure. The upper outer cylinder 10 is sleeved on the upper outer part of the middle cylinder 11, and the top is open. The outer ring of the upper outer cylinder 10 is equipped with a hydraulic buffer 9 and a magnetic damping device 8. The middle part of the middle cylinder 11 is provided with a mounting groove for installing the voice coil motor 6 and the transverse groove spring 3. The outer periphery of the middle cylinder 11 is provided with a blind hole for placing the magnetic damping device 8, and the magnetic damping device 8 can be matched with the blind hole gap.

[0116] like Figures 1 to 3 As shown, a boss is provided at the center of the table of the output plate 7 for connecting with the diaphragm spring 4, and a plurality of bent beams extend from the periphery of the table. The bent beams pass through the slots provided on the side walls of the middle cylinder 11 and the upper outer cylinder 10, and are connected to the load platform 1 through the flexible hinge 5. The magnetic damping device 8 is located below the cross plate of the bent beam and is gap-matched with the blind hole of the middle cylinder 11.

[0117] The lower end of the stator of the voice coil motor 6 is fixed in the first mounting groove of the middle cylinder 11 by a fastener, and the mover of the voice coil motor 6 is connected to the platform of the output plate 7 .

[0118] The diaphragm spring 4 and the output plate 7 are provided with through holes for matching positions. One end of the connecting rod 2 is connected to the load platform 1, and the other end passes through the through hole to connect with the upper end of the transverse groove spring 3. The lower end of the transverse groove spring 3 is installed on the middle cylinder 11 through four countersunk bolts, and the upper end supports the load platform 1 through the connecting rod 2. The center of the diaphragm spring 4 is fixed to the boss of the output plate 7 by bolts, and the outer periphery is pressed by the upper outer cylinder 10 and the middle cylinder 11 to save the height of the shock absorber.

[0119] The voice coil motor 6, controller 13 and acceleration sensor 12 of the active vibration reduction unit together form a closed-loop control system. The acceleration sensor 12 detects the vibration signal, and the controller 13 adjusts the output of the voice coil motor 6 according to the vibration signal. The transmission path of the active action power output by the voice coil motor 6 is from the output plate 7 to the flexible hinge 5 and then to the load platform 1, realizing active vibration isolation.

[0120] The transverse groove spring 3 which plays a supporting role is connected in parallel with the voice coil motor 6 which plays an active vibration control role, forming a typical second-order active-passive composite vibration reduction model, which can reduce the natural frequency and resonance peak value of the system, while ensuring high attenuation of high-frequency vibration, and realizing vibration isolation and noise reduction in a wider bandwidth.

[0121] The cooperation of the flexible hinge 5 and the diaphragm spring 4 of the present invention not only ensures the coaxiality of the stator and the mover of the voice coil motor 6 but also reduces the loss of the motor output force; the transverse groove spring 3 connected in series with the diaphragm spring 4 realizes adjustable stiffness through the depth of the screw-in connection bolts; the output plate 7 of the bent beam structure is used in the design to cooperate with the flexible hinge 5, and the oil buffer is used as an auxiliary to enhance the ability of the vibration isolator to resist impact loads. The magnetic damping device 8 generates magnetic damping force through the relative movement between the annular permanent magnet on the upper guide column and the column tube. In order to ensure that the actuating force of the active control is not affected, the device designs the upper and lower guide column permanent magnets with magnetic poles in opposite directions and leaves a gap between the bent beams.

[0122] The acceleration sensor 12 of the present invention collects the vibration response signal on the load platform 1 and transmits it to the system controller 13. After being processed by the control algorithm, the system generates a corresponding control signal, adjusts the actuator of the voice coil motor 6 to offset the vibration excitation, and realizes closed-loop feedback control. This control method effectively reduces the resonance peak amplitude at the natural frequency, while providing high attenuation performance in the high frequency band. The present invention has a compact structure, adjustable stiffness, and can achieve efficient vibration reduction in a wide frequency range.

[0123] To sum up, the active and passive composite shock absorber disclosed in the present invention can be used as a shipborne auxiliary equipment. The equipment is miniaturized and lightweight, and combined with the advantages of active and passive vibration reduction, it can weaken the vibration of electronic equipment caused by impact on ships, aircraft and ships in fluids without changing the installation requirements, thereby effectively preventing damage to shipborne electronic equipment due to excessive vibration.

[0124] The above description and the accompanying drawings sufficiently illustrate the embodiments of the present disclosure to enable those skilled in the art to practice them. Other embodiments may include structural and other changes. The embodiments represent only possible variations. Unless explicitly required, individual components and functions are optional, and the order of operations may vary. Portions and features of some embodiments may be included in or replace portions and features of other embodiments. The embodiments of the present disclosure are not limited to the structures described above and shown in the accompanying drawings, and various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. An active and passive composite shock absorber with adjustable stiffness, characterized in that: It comprises a load platform (1), a support unit, a connection unit, an active vibration reduction unit and a passive vibration reduction unit; The load platform (1) is the uppermost layer of the entire device and is used to carry equipment or objects that require vibration reduction; The support unit is used to support the active vibration reduction unit and the passive vibration reduction unit; The active vibration reduction unit is used to actively detect and adjust vibration to achieve active vibration reduction; The passive vibration reduction unit is used to cooperate with the active vibration reduction unit to form a second-order active-passive composite vibration reduction model, and the passive vibration reduction unit includes a transverse groove spring (3); The connection unit is used to connect the load platform (1) with the active vibration reduction unit and the passive vibration reduction unit, and the connection unit comprises a connection rod (2); The lower end of the transverse groove spring (3) is connected to the support unit, and the upper end supports the load platform (1) through the connecting rod (2); a through hole is provided at a portion of the transverse groove spring (3) corresponding to the connecting rod (2); The fastener can pass through the load platform (1) and the connecting rod (2) and be screwed into the transverse groove spring (3). The rigidity of the transverse groove spring (3) can be adjusted by adjusting the screwing depth of the fastener into the transverse groove spring (3).

2. The active and passive composite shock absorber according to claim 1, characterized in that: The expression of the axial stiffness of the transverse groove spring (3) is: Where E is the elastic modulus of the circular beam, and the radial wedge width a is t , layer beam thickness h, n t is the total number of the transverse groove spring layer beams, R0 represents the radius of each layer of circular beams, μ is the Poisson's ratio; γ is the section modulus of the circular beam. When the screw is screwed into the transverse groove spring (3), the layer beam changes its axial stiffness.

3. The active and passive composite shock absorber according to claim 2, characterized in that: The active vibration reduction unit comprises a voice coil motor (6), a controller (13) and an acceleration sensor (12); The output end of the acceleration sensor (12) is connected to the input end of the controller (13), the output end of the controller (13) is connected to the input end of the voice coil motor (6), and the voice coil motor (6), the controller (13) and the acceleration sensor (12) together constitute a closed-loop control system; The acceleration sensor (12) collects signals, which are processed by the controller (13), and the voice coil motor (6) actuator outputs an actuating force to offset the residual vibration, thereby forming an active and passive composite vibration isolation mechanism together with the passive vibration reduction unit.

4. The active and passive composite shock absorber according to claim 3, characterized in that: The controller (13) adopts an integral force (IFF) feedback control law based on the ceiling damping technology, and its frequency domain form can be expressed as: In the formula, F P Represents the force signal of the load platform, C FP It is expressed as the feedback control rate, s is the complex variable of Laplace complex transform, which is used for frequency domain analysis, x0 represents the original vibration excitation of the base platform, M P is the load mass, Λ is the gain coefficient of the ceiling damping, k i =M P ·Λ is the integral gain coefficient of IFF feedback control.

5. The active and passive composite shock absorber according to any one of claims 1 to 4, characterized in that: The support unit comprises an upper outer cylinder (10) and a middle cylinder (11) which are coaxially arranged. The upper outer cylinder (10) and the middle cylinder (11) are structurally matched, the upper outer cylinder (10) is sleeved on the outside of the middle cylinder (11), and the top is open; A mounting groove is arranged in the middle of the middle cylinder (11), and a blind hole is arranged on the outer periphery of the middle cylinder (11).

6. The active and passive composite shock absorber according to claim 5, characterized in that: The connection unit further comprises a flexible hinge (5) and an output plate (7); The output plate (7) comprises a table top and a bent beam. A boss is arranged at the center of the table top. A plurality of bent beams extend from the periphery of the table top. The bent beams are L-shaped structures. The horizontal plates of the bent beams pass through the slots arranged on the side walls of the middle cylinder (11) and the upper outer cylinder (10), and are connected to the load platform (1) via a flexible hinge (5).

7. The active and passive composite shock absorber according to claim 6, characterized in that: The passive vibration reduction unit also includes a diaphragm spring (4) and a magnetic damping device (8). The diaphragm spring (4) is located on the upper part of the transverse groove spring (3), the center of the diaphragm spring (4) is connected and fixed to the boss of the output plate (7) through a fastener, and the outer periphery is pressed by the upper outer cylinder (10) and the middle cylinder (11); The magnetic damping device (8) is located below the bent beam transverse plate and is gap-matched with the blind hole of the middle cylinder (11).

8. The active and passive composite shock absorber according to claim 7, characterized in that: The diaphragm spring (4) and the output plate (7) are provided with through holes that match each other in position. One end of the connecting rod (2) is connected to the load platform (1), and the other end passes through the through hole and is connected to the upper end of the transverse groove spring (3).

9. The active and passive composite shock absorber according to claim 6, characterized in that: The stator of the voice coil motor (6) is fixed in the middle cylinder (11), and the mover is connected to the output plate (7); The transverse groove spring (3) is sleeved on the outside of the voice coil motor (6), and the lower end is connected and fixed to the middle tube (11).

10. The active and passive composite shock absorber according to claim 6, characterized in that: The outer ring of the upper outer cylinder (10) is surrounded by an oil pressure buffer (9) and a magnetic damping device (8).

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