A three-degree-of-freedom parallel vibration isolation platform with quasi-zero stiffness characteristics

Abstract

A three-degree-of-freedom parallel vibration isolation platform with quasi-zero stiffness characteristics, including a static platform connected to an external base platform, a dynamic platform carrying a vibration-isolated device, a branch chain, and a quasi-zero stiffness mechanism; the dynamic platform bottom plate 12 is connected to a branch chain every 120 degrees radially from the centroid as the center of the circle, and the branch chain is mounted on the support frame bottom plate 7 of the static platform; the dynamic platform bottom plate 12 supports a vertical spring 6 at the radial position, and the bottom of the vertical spring 6 is supported on the static platform bottom plate 1; the dynamic platform bottom plate 12 is connected to the branch chain through a rotating shaft mounting seat 19; the branch chain includes a parallelogram mechanism composed of a first rotating shaft 18, a second rotating shaft 18a and two connecting rods 11, which ensures that the dynamic platform always maintains a horizontal state when moving in space; the horizontal spring 10 and the vertical spring 6 constitute the quasi-zero stiffness mechanism. The present invention has a simple and compact structure, flexible motion characteristics, and meets the requirements of three-degree-of-freedom spatial translation vibration isolation.

Description

Technical Field

[0001] The invention relates to a parallel mechanism, in particular to a three-degree-of-freedom parallel vibration isolation platform with quasi-zero stiffness characteristics. Background Art

[0002] Vehicle-mounted instruments and equipment will inevitably be affected by vibrations during driving, which will affect the reliability of the vehicle-mounted instruments and equipment.

[0003] The vibration of mechanical equipment can be decomposed into vibrations in six coordinate directions. my country's military standards and the vibration and shock standards of some precision instruments and equipment have put forward clear requirements for the vibration and shock response in three translation directions. The three-degree-of-freedom vibration isolation mechanism can well meet this requirement.

[0004] Compared with the vibration isolation problem of medium and high frequency vibration, it is more difficult to solve the low-frequency vibration isolation problem using existing technology. Further reducing the natural frequency of the vibration isolation system is one of the effective means to achieve low-frequency vibration isolation. However, reducing the natural frequency by reducing the stiffness of the vibration isolation system will lead to insufficient bearing capacity of the system, and in severe cases will cause excessive static deformation or instability of the system. The quasi-zero stiffness mechanism formed by parallel connection of positive and negative stiffness mechanisms can reduce the natural frequency of the vibration isolation system while ensuring the bearing capacity of the vibration isolation system, and is an important means to solve the low-frequency vibration isolation problem.

[0005] In terms of three-degree-of-freedom vibration isolation, the patent "A low-frequency three-degree-of-freedom vibration isolator" CN101832352A discloses a three-degree-of-freedom vibration isolation device. The vibration isolation device consists of an air spring and a pair of hollow cylindrical permanent magnets. The outer hollow cylindrical water magnet is fixed on the top of the air spring body, and the inner hollow cylindrical permanent magnet is fixed on the rubber piston of the air spring to achieve three-degree-of-freedom vibration isolation. The defect of this mechanism is that when the design natural frequency is low, the volume of the air spring chamber will be too large, resulting in unstable position control, which makes it unable to work normally. Therefore, the air spring cannot meet the requirements of low-frequency / ultra-low-frequency vibration isolation; the patent "A three-degree-of-freedom active vibration isolation platform" CN104976488A discloses a three-degree-of-freedom active vibration isolation platform, which consists of an upper platform, a lower platform, a first telescopic rod, a second telescopic rod, a third telescopic rod, a cantilever and a crossbeam, which can reduce the upper platform's up and down translation and left and right swing vibration. The defect of this mechanism is that the natural frequency of the vibration isolation system is large and low-frequency / ultra-low-frequency vibration isolation cannot be achieved, and the working space is small. Patent "A three-degree-of-freedom parallel attitude adjustment vibration isolation platform with tower-shaped telescopic branches" CN105563466A and patent "A three-degree-of-freedom parallel attitude adjustment vibration isolation platform with variable angle branches" CN105538293A disclose two similar three-degree-of-freedom parallel vibration isolation platforms. Although they can achieve three-degree-of-freedom vibration isolation, the natural frequency of the vibration isolation system is relatively large and cannot achieve low-frequency vibration isolation.

[0006] In terms of vibration isolation of quasi-zero stiffness mechanisms, the patent "A quasi-zero stiffness vibration isolator with positive and negative stiffness in parallel" CN108662055A, the patent "A quasi-zero stiffness vibration isolator with positive and negative stiffness in parallel" CN109139760A, and the patent "A positive and negative stiffness parallel shock absorber" CN103256332A all design vibration isolation devices with quasi-zero stiffness characteristics based on the quasi-zero stiffness theory. However, the common defect of the above invention patents is that the moving parts have only a single degree of freedom in a single direction and only have a single degree of freedom vibration isolation effect, which limits their scope of engineering application.

[0007] Patent "A positive and negative stiffness parallel three-translation vibration and impact isolation platform" CN101871505A discloses a three-degree-of-freedom vibration isolation platform using a quasi-zero stiffness vibration isolator. The device consists of an upper platform, a lower platform, 8 elastic branch chain structures and a silicone magnetorheological damper. The 8 elastic branch chain structures are fixed between the upper platform and the lower platform in pairs in a 4-point orthogonal symmetrical support manner, and the axes of the two elastic branch chain structures at each point are perpendicular to each other; the silicone magnetorheological damper is set at the geometric center between the upper platform and the lower platform. This vibration isolation device simply arranges multiple single-degree-of-freedom quasi-zero stiffness vibration isolators so that the upper platform can only move in translation on the three axes of the X-axis, Y-axis, and Z-axis. Multiple vibration isolators are prone to affect each other, reducing the vibration isolation performance of the platform. At the same time, the platform has a small working space, a large volume, and a complex structure, which limits its engineering application.

[0008] In summary, the existing three-degree-of-freedom vibration isolation mechanism cannot obtain good low-frequency vibration isolation performance, and the existing quasi-zero stiffness vibration isolators with positive and negative stiffness in parallel have good low-frequency / ultra-low-frequency vibration isolation performance, but cannot achieve three-degree-of-freedom vibration isolation. The limitations of these technologies make them unable to be used to solve the low-frequency three-degree-of-freedom vibration isolation problem. Summary of the invention

[0009] In order to overcome the above problems, the present invention provides a three-degree-of-freedom parallel vibration isolation platform with a simple and compact structure and a quasi-zero stiffness characteristic.

[0010] The technical solution adopted by the present invention is: a three-degree-of-freedom parallel vibration isolation platform with quasi-zero stiffness characteristics, including a static platform connected to an external base platform, a dynamic platform carrying a vibration-isolated device, a branch chain, and a quasi-zero stiffness mechanism;

[0011] The bottom plates of the static platform and the dynamic platform are both in the shape of horizontally arranged flat plates. The dynamic platform bottom plate 12 is connected to a branch chain in a radial direction of every 120 degrees from the center of the shape as the center of the circle. The branch chain is mounted on the support frame bottom plate 7 of the static platform. The radial direction constitutes the shape symmetry line of the dynamic platform bottom plate 12. The dynamic platform bottom plate 12 supports a vertical spring 6 at the radial position, and the bottom of the vertical spring 6 is supported on the static platform bottom plate 1.

[0012] The moving platform bottom plate 12 is connected to the branch chain through the rotating shaft mounting seat 19;

[0013] The static platform bottom plate 1 is provided with a support frame 3 at the corresponding radial position, and a horizontally arranged support frame bottom plate 7 is installed on the top of the support frame 3. A horizontal spring 10 and a linear slider guide rail module 21 arranged along the radial direction are installed on the support frame bottom plate 7. The linear slider guide rail module 21 includes a radially arranged guide rail, and the horizontal spring 10 is arranged between the first horizontal spring mounting seat 8 and the rotating shaft slider 13;

[0014] The branch chain includes: a rotating shaft slider 13 slidably arranged on a guide rail, the rotating shaft slider 13 is connected to a rotating shaft mounting seat 19 through a parallelogram mechanism, the parallelogram mechanism includes a first rotating shaft 18 arranged on the rotating shaft mounting seat 19, a second rotating shaft 18a arranged on the rotating shaft slider 13, and a connecting rod 11 with two ends respectively hinged to the first rotating shaft 18 and the second rotating shaft 18a, the connecting rod 11 is parallel to the radial direction, the first rotating shaft 18 and the second rotating shaft 18a are perpendicular to the radial direction, and the plane where the parallelogram mechanism is located is parallel to the moving platform bottom plate 12;

[0015] The horizontal spring 10 and the vertical spring 6 constitute the quasi-zero stiffness mechanism.

[0016] Further, the static platform includes a support frame 3 arranged on the static platform bottom plate 1, the support frame 3 is fitted with a support frame rib 4, the longitudinal section of the support frame rib 4 is an inverted L-shape, the vertical side of the support frame rib 4 is fixedly connected to the support frame 3, the horizontal side of the support frame rib 4 is flush with the top of the support frame 3, and the support frame base 7 is arranged on the top surface of the support frame rib 4 and the support frame 3; the linear slider guide module 21 includes a guide rail and a slider slidably connected to the guide rail, the end of the linear slider guide module 21 away from the moving platform is provided with a first horizontal spring mounting seat 8, and the end of the linear slider guide module 21 close to the moving platform is provided with a second horizontal spring mounting seat 8a for preventing the slider from exceeding the stroke; a plurality of groups of screw holes for installing the horizontal spring mounting seat 8 are provided on the support frame base 7 along the radial direction, and the horizontal spring mounting seat 8 is also provided with a horizontal spring guide column 9 for installing the horizontal spring 10;

[0017] The bottom of the vertical spring 6 is supported by a static platform vertical spring guide column 2 arranged on the static platform bottom plate 1. A limiting step is provided on the top of the static platform vertical spring guide column 2. The vertical spring sleeve 5 is installed on the upper surface of the limiting step. The top of the vertical spring sleeve 5 is sleeved with a vertical spring 6.

[0018] Further, the branch chain includes a rotating shaft slider 13, the rotating shaft slider 13 is arranged at the top of the slider, and the rotating shaft slider 13 is slidably connected to the guide rail through the slider. 4. A three-degree-of-freedom parallel vibration isolation platform with quasi-zero stiffness characteristics as claimed in claim 1, characterized in that: the lower surface of the moving platform bottom plate is provided with a rotating shaft mounting seat 19 for connecting with the branch chain and a moving platform vertical spring guide column 22 for installing the vertical spring 6.

[0019] Furthermore, the horizontal spring 10 in the quasi-zero stiffness mechanism is arranged between the first horizontal spring mounting seat 8 of the static platform and the rotating shaft slider 13 of the branch chain, and the compression amount of the horizontal spring is adjusted by changing the installation position of the first horizontal spring mounting seat 8; the vertical spring 6 is arranged between the lower surface of the moving platform bottom plate 12 and the vertical spring sleeve 5 of the static platform, and the compression amount of the vertical spring 6 is adjusted by changing the thickness of the vertical spring sleeve 5.

[0020] The beneficial effects of the present invention are: 1) This vibration isolation platform designs a new type of three-degree-of-freedom parallel mechanism, which is simple and compact, has flexible motion characteristics, and meets the requirements of three-degree-of-freedom spatial translational vibration isolation. 2) This vibration isolation platform introduces the quasi-zero stiffness theory into the design of the three-degree-of-freedom parallel mechanism, and obtains a parallel vibration isolation platform with quasi-zero stiffness characteristics and three-degree-of-freedom directional vibration isolation effects. Quasi-zero stiffness is generated in the vertical direction to ensure the vertical bearing capacity while reducing the vertical natural frequency of the vibration isolation platform. The horizontal spring group in the quasi-zero stiffness structure ensures that the vibration isolation platform also has a good vibration isolation effect in the horizontal direction. 3) The compression amount of the horizontal spring and the vertical spring of this vibration isolation platform is adjustable, and the quasi-zero stiffness can be adjusted according to the different vibration isolation equipment and usage requirements to ensure low-frequency three-degree-of-freedom vibration isolation performance, and has a certain adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the present invention.

[0022] Figure 2 It is the front view of the present invention.

[0023] Figure 3 It is a top view of the present invention.

[0024] Figure 4 It is a structural schematic diagram of the static platform and the spring group of the present invention.

[0025] Figure 5 It is a structural schematic diagram of the moving platform of the present invention.

[0026] Figure 6 It is a schematic diagram of the structure of the branched chain of the present invention.

[0027] Figure 7 The present invention relates to a quasi-zero stiffness mechanism principle diagram.

[0028] Figure 8 This is the stiffness characteristic curve 1 of the quasi-zero stiffness mechanism involved in the present invention.

[0029] Fig. 9 This is the stiffness characteristic curve 2 of the quasi-zero stiffness mechanism involved in the present invention.

[0030] Fig.10 It is a function simulation diagram of the vertical vibration isolation transmission of the present invention.

[0031] Explanation of the reference numerals in the accompanying drawings: 1. static platform base plate; 2. static platform vertical spring guide column; 3. support frame; 4. support frame rib plate; 5. vertical spring sleeve; 6. vertical spring; 7. support frame base plate; 8. first horizontal spring mounting seat; 8a. second horizontal spring mounting seat; 9. horizontal spring guide column; 10. horizontal spring; 11. connecting rod; 12. dynamic platform base plate; 13. shaft slider; 14. first shaft bearing; 15. connecting rod shaft; 16. first retaining spring; 17. connecting rod shaft bearing; 18. first shaft; 18a. second shaft; 19. shaft mounting seat; 20. shaft bearing sleeve; 21. linear slider guide module; 22. dynamic platform vertical spring guide column. DETAILED DESCRIPTION

[0032] The present invention is further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto:

[0033] Referring to the attached drawings, a three-degree-of-freedom parallel vibration isolation platform with quasi-zero stiffness characteristics includes a static platform connected to an external base platform, a dynamic platform carrying a vibration-isolated device, a branch chain, and a quasi-zero stiffness mechanism;

[0034] The bottom plates of the static platform and the dynamic platform are both in the shape of horizontally arranged flat plates. The dynamic platform bottom plate 12 is connected to a branch chain in a radial direction of every 120 degrees from the center of the shape as the center of the circle. The branch chain is mounted on the support frame bottom plate 7 of the static platform. The radial direction constitutes the shape symmetry line of the dynamic platform bottom plate 12. The dynamic platform bottom plate 12 supports a vertical spring 6 at the radial position, and the bottom of the vertical spring 6 is supported on the static platform bottom plate 1.

[0035] The movable platform bottom plate 12 is connected to the branch chain through the rotating shaft mounting seat 19; the lower surface of the movable platform bottom plate is provided with a rotating shaft mounting seat 19 for connecting with the branch chain and a movable platform vertical spring guide column 22 for mounting the vertical spring 6;

[0036] The static platform bottom plate 1 is provided with a support frame 3 at the corresponding radial position, and the support frame 3 is fitted with a support frame rib 4, the longitudinal section of the support frame rib 4 is an inverted L-shape, the vertical side of the support frame rib 4 is fixedly connected to the support frame 3, the horizontal side of the support frame rib 4 is flush with the top of the support frame 3, and the support frame base 7 is horizontally arranged on the top surface of the support frame rib 4 and the support frame 3; the support frame bottom plate 7 is installed with a horizontal spring 10 and a linear slider guide rail module 21 arranged along the radial direction, the linear slider guide rail module 21 includes a radially arranged guide rail and a slider slidably connected to the guide rail, and the rotating shaft slider 13 is arranged at the top of the slider; the linear slider guide rail module 21 is provided with a first horizontal spring mounting seat at the end away from the moving platform 8. A second horizontal spring mounting seat 8a is provided at one end of the linear slider guide module 21 close to the moving platform to prevent the slider from exceeding the stroke; the horizontal spring 10 is arranged between the first horizontal spring mounting seat 8 and the rotating shaft slider 13; a plurality of groups of screw holes for installing the horizontal spring mounting seat 8 are provided on the support frame base 7 along the radial direction, and a horizontal spring guide column 9 for installing the horizontal spring 10 is also provided on the horizontal spring mounting seat 8; the bottom of the vertical spring 6 is supported by a static platform vertical spring guide column 2 arranged on the static platform bottom plate 1, and a limiting step is provided on the top of the static platform vertical spring guide column 2, and the vertical spring sleeve 5 is installed on the upper surface of the limiting step, and the vertical spring 6 is sleeved on the top of the vertical spring sleeve 5.

[0037] The branch chain includes: a rotating shaft slider 13 is arranged at the top of the slider, and the rotating shaft slider 13 is slidably connected to the guide rail through the slider; the rotating shaft slider 13 is connected to the rotating shaft mounting seat 19 through a parallelogram mechanism, and the parallelogram mechanism includes a first rotating shaft 18 arranged on the rotating shaft mounting seat 19, a second rotating shaft 18a arranged on the rotating shaft slider 13, and a connecting rod 11 whose two ends are respectively hinged to the first rotating shaft 18 and the second rotating shaft 18a through a connecting rod rotating shaft 15, the connecting rod 11 is parallel to the radial direction, the first rotating shaft 18 and the second rotating shaft 18a are perpendicular to the radial direction, and the plane where the parallelogram mechanism is located is parallel to the moving platform bottom plate 12; the connecting rod rotating shaft 15 is perpendicular to the plane where the parallelogram mechanism is located, and the connecting rod rotating shaft 15 Both ends of the shaft are provided with connecting rod rotating shaft bearings 17, the outer end surface of the connecting rod rotating shaft bearing 17 is limited by the first retaining spring 16, and the connecting rod 11 can rotate freely around the connecting rod rotating shaft 15; the first rotating shaft 18 is installed on the rotating shaft mounting seat 19 through the first rotating shaft bearing 14, the first rotating shaft bearing 14 is positioned by the first rotating shaft bearing sleeve 20 and the second retaining spring, and the first rotating shaft 18 can rotate freely in the rotating shaft mounting seat 19; the second rotating shaft 18a is installed on the rotating shaft slider 13 through the second rotating shaft bearing, the second rotating shaft bearing is positioned by the second rotating shaft bearing sleeve and the third retaining spring, and the second rotating shaft 18a can rotate freely in the rotating shaft slider 13, and the rotating shaft mounting seat is fixed to the lower surface of the moving platform bottom plate 12 by screws.

[0038] The horizontal spring 10 and the vertical spring 6 constitute the quasi-zero stiffness mechanism. The horizontal spring 10 is arranged between the first horizontal spring mounting seat 8 of the static platform and the rotating shaft slider 13 of the branch chain. The compression amount of the horizontal spring can be adjusted by changing the installation position of the first horizontal spring mounting seat 8; the vertical spring 6 is arranged between the lower surface of the bottom plate 12 of the dynamic platform and the vertical spring sleeve 5 of the static platform. The compression amount of the vertical spring 6 can be adjusted by changing the thickness of the vertical spring sleeve 5.

[0039] Its specific working principle is: in the initial state, the moving platform, the connecting rod 11, and the horizontal spring 10 are all in a horizontal state and in the same horizontal plane; under the action of external excitation, the moving platform leaves the equilibrium position, and due to the limitation of the parallelogram mechanism, the moving platform can only move horizontally in space; by selecting appropriate stiffness values ​​of the horizontal spring 10 and the vertical spring 6, the moving platform can always move within the quasi-zero stiffness position range, and under the action of the quasi-zero stiffness mechanism, the system stiffness is affected, so that the entire mechanism has a vibration isolation effect.

[0040] Figure 7 The schematic diagram of a quasi-zero stiffness mechanism of a three-degree-of-freedom vibration isolation platform with quasi-zero stiffness characteristics of the present invention is shown in FIG. 1 , wherein G is the gravity of the dynamic platform mechanism and the vibration-isolated device; L is the length of the connecting rod; λ and k h is the pre-compression amount and stiffness of the horizontal spring; P is the pre-compression force generated by the horizontal spring; k v is the stiffness of the vertical support spring; x is the vertical distance of the moving platform away from the equilibrium position. Select a suitable vertical spring stiffness so that the moving platform, connecting rod and horizontal spring are in the same horizontal plane in the initial state; according to the virtual displacement principle, the stiffness generated by the quasi-zero stiffness mechanism is:

[0041]

[0042] When the vertical distance x of the moving platform from the equilibrium position satisfies the following formula, the quasi-zero stiffness mechanism takes effect, making the vibration isolation platform have a quasi-zero stiffness characteristic:

[0043]

[0044] Figure 8 , Fig. 9 : is a stiffness characteristic curve of a three-degree-of-freedom vibration isolation platform with quasi-zero stiffness characteristics under different conditions of the present invention, in which λ0 is the ratio of the pre-compression of the horizontal spring to the length of the connecting rod L; α is the ratio of the vertical spring stiffness to the horizontal spring; Figure 8 , Fig. 9 It can be seen that the structural parameter values ​​of the quasi-zero stiffness mechanism affect the stiffness value of the quasi-zero stiffness and the range of the quasi-zero stiffness. Therefore, appropriate structural parameters are selected according to different vibration isolation requirements and working conditions.

[0045] Fig.10 This is a simulation diagram of the vertical vibration isolation transfer function of a three-degree-of-freedom vibration isolation platform with a quasi-zero stiffness characteristic according to an embodiment of the present invention. The solid line in the figure is the vertical vibration isolation transfer function curve of the three-degree-of-freedom vibration isolation platform with a quasi-zero stiffness characteristic, and the dotted line is the vertical vibration isolation transfer function curve of an ordinary vibration isolation platform without a quasi-zero stiffness mechanism. From the comparison of the two curves, it can be seen that the natural frequency of the vibration isolation platform is significantly shifted forward after the quasi-zero stiffness mechanism is adopted. It can be seen that the three-degree-of-freedom vibration isolation platform with a quasi-zero stiffness characteristic of the present invention can effectively reduce the natural frequency of the vibration isolation system, broaden the vibration isolation frequency band, and effectively improve the vibration isolation performance compared to the ordinary vibration isolation system.

[0046] The contents described in the embodiments of this specification are merely an enumeration of the implementation forms of the inventive concept. The protection scope of the present invention should not be regarded as limited to the specific forms described in the embodiments. The protection scope of the present invention also extends to equivalent technical means that can be conceived by those skilled in the art based on the inventive concept.

Claims

1. A three-degree-of-freedom parallel vibration isolation platform with quasi-zero stiffness characteristics, characterized in that: It includes a static platform connected to an external base platform, a dynamic platform carrying the vibration-isolated equipment, a branch chain, and a quasi-zero stiffness mechanism; The base plates of the static platform and the dynamic platform are both in the shape of horizontally arranged flat plates. The dynamic platform base plate (12) is connected to a branch chain in a radial direction of every 120 degrees from the center of the shape as the center of the circle. The branch chain is mounted on the support frame base plate (7) of the static platform. The radial direction constitutes the shape symmetry line of the dynamic platform base plate (12). The dynamic platform base plate (12) supports a vertical spring (6) at the radial position, and the bottom of the vertical spring (6) is supported on the static platform base plate (1); The movable platform bottom plate (12) is connected to the branch chain via a rotating shaft mounting seat (19); The stationary platform bottom plate (1) is provided with a support frame (3) at the corresponding radial position, the top of the support frame (3) is provided with a horizontally arranged support frame bottom plate (7), the support frame bottom plate (7) is provided with a horizontal spring (10) and a linear slider guide rail module (21) arranged along the radial direction, the linear slider guide rail module (21) includes a radially arranged guide rail, and the horizontal spring (10) is arranged between the first horizontal spring mounting seat (8) and the rotating shaft slider (13); The branch chain comprises: a rotating shaft slider (13) slidably arranged on a guide rail, the rotating shaft slider (13) is connected to a rotating shaft mounting seat (19) through a parallelogram mechanism, the parallelogram mechanism comprises a first rotating shaft (18) arranged on the rotating shaft mounting seat (19), a second rotating shaft (18a) arranged on the rotating shaft slider (13), and a connecting rod (11) hinged to the first rotating shaft (18) and the second rotating shaft (18a) at both ends, respectively, the connecting rod (11) is parallel to the radial direction, the first rotating shaft (18) and the second rotating shaft (18a) are perpendicular to the radial direction, and the plane where the parallelogram mechanism is located is parallel to the movable platform bottom plate (12); The horizontal spring (10) and the vertical spring (6) constitute the quasi-zero stiffness mechanism; The static platform comprises a support frame (3) arranged on a static platform bottom plate (1); the support frame (3) is fitted with a support frame rib plate (4); the longitudinal section of the support frame rib plate (4) is in an inverted L shape; the vertical side of the support frame rib plate (4) is fixedly connected to the support frame (3); the horizontal side of the support frame rib plate (4) is flush with the top of the support frame (3); the support frame bottom plate (7) is arranged on the top surface of the support frame rib plate (4) and the support frame (3); the linear slider guide rail module (21) comprises a guide rail and a slide block slidably connected to the guide rail A slider, a first horizontal spring mounting seat (8) is provided at one end of the linear slider guide rail module (21) away from the moving platform, and a second horizontal spring mounting seat (8a) is provided at one end of the linear slider guide rail module (21) close to the moving platform for preventing the slider from exceeding the stroke; a plurality of groups of screw holes for mounting the first horizontal spring mounting seat (8) are provided on the support frame bottom plate (7) along the radial direction, and a horizontal spring guide column (9) for mounting a horizontal spring (10) is also provided on the first horizontal spring mounting seat (8); The bottom of the vertical spring (6) is supported by a static platform vertical spring guide column (2) arranged on the static platform bottom plate (1); a limiting step is arranged on the top of the static platform vertical spring guide column (2); a vertical spring sleeve (5) is installed on the upper surface of the limiting step; and a vertical spring (6) is sleeved on the top of the vertical spring sleeve (5); The lower surface of the movable platform bottom plate is provided with a rotating shaft mounting seat (19) for connecting with the branch chain and a movable platform vertical spring guide column (22) for mounting a vertical spring (6); The horizontal spring (10) in the quasi-zero stiffness mechanism is arranged between the first horizontal spring mounting seat (8) of the static platform and the rotating shaft slider (13) of the branch chain, and the compression amount of the horizontal spring is adjusted by changing the installation position of the first horizontal spring mounting seat (8); the vertical spring (6) is arranged between the lower surface of the dynamic platform bottom plate (12) and the vertical spring sleeve (5) of the static platform, and the compression amount of the vertical spring (6) is adjusted by changing the thickness of the vertical spring sleeve (5).

2. A three-degree-of-freedom parallel vibration isolation platform with quasi-zero stiffness characteristics as claimed in claim 1, characterized in that: The branch chain comprises a rotating shaft slider (13), the rotating shaft slider (13) is arranged at the top of the slider, and the rotating shaft slider (13) is slidably connected to the guide rail through the slider.

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