Quasi-zero stiffness passive vibration isolation table

Abstract

The quasi-zero stiffness passive vibration isolation platform is beneficial to solving the problems of high natural frequency, difficult to adjust quasi-zero stiffness, and poor vibration isolation effect of existing vibration isolation platforms. It is characterized in that it includes a vertical vibration isolator and a horizontal vibration isolator arranged below the load platform, and the vertical vibration isolator and the horizontal vibration isolator are both located in the support seat. The vertical vibration isolator has a vertical negative stiffness mechanism, and the vertical negative stiffness mechanism has a lateral adjustment mechanism. The load platform is used to place the object to be isolated. The vertical vibration isolator and the horizontal vibration isolator are fixedly connected by a ball joint inverted pendulum, and the support seat is connected to the foundation.

Description

Technical Field

[0001] The invention belongs to the technical field of precision vibration isolation, and in particular relates to a quasi-zero stiffness passive vibration isolation platform. Background Art

[0002] With the continuous improvement of the precision of precision measuring instruments and precision processing and manufacturing equipment, the requirements for the micro-vibration environment of the equipment have increased dramatically, especially the interference suppression of low-frequency vibration. Passive vibration isolation platforms reduce the transmission of vibration to the isolated object by reasonably setting mechanical structures such as springs and damping. They have the characteristics of simple structure and high reliability, and can isolate frequencies greater than the natural frequency of the vibration isolation platform. times the vibration interference. To achieve ultra-low frequency vibration suppression, it is necessary to further reduce the natural frequency of the vibration isolation system. Quasi-zero stiffness vibration isolation is an effective solution. By connecting a negative stiffness mechanism and a positive stiffness element in parallel, quasi-zero stiffness is achieved at the static equilibrium position, significantly reducing the natural frequency of the vibration isolation system, thereby achieving ultra-low frequency vibration isolation characteristics.

[0003] Existing quasi-zero-stiffness isolators have a narrow operating range and are often limited to a single load. Once the isolator is manufactured, the structural parameters are difficult to change, making them unable to meet the vibration isolation requirements of different objects. Some adjustable quasi-zero-stiffness isolators have multiple levels of stiffness, but these only achieve quasi-zero stiffness for a few specific load masses and cannot achieve continuous stiffness variation. Therefore, designing a continuously adjustable quasi-zero-stiffness passive vibration isolation platform is a key issue currently under investigation in this field. Summary of the Invention

[0004] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a quasi-zero stiffness passive vibration isolation platform, which is conducive to solving the problems of high natural frequency, difficult adjustment of quasi-zero stiffness and poor vibration isolation effect of the existing vibration isolation platform.

[0005] The technical solutions of the present invention are as follows:

[0006] A quasi-zero stiffness passive vibration isolation platform is characterized in that it includes a vertical vibration isolator and a horizontal vibration isolator arranged below the load platform, the vertical vibration isolator and the horizontal vibration isolator are both located in a support seat, the vertical vibration isolator has a vertical negative stiffness mechanism, the vertical negative stiffness mechanism has a lateral adjustment mechanism, the load platform is used to place the object to be isolated, the vertical vibration isolator and the horizontal vibration isolator are fixedly connected by a ball joint inverted pendulum, and the support seat is connected to the foundation.

[0007] The upper end of the ball joint inverted pendulum (33) is connected to the horizontal vibration isolation platform (31) of the horizontal vibration isolator (3), and the lower end of the ball joint inverted pendulum (33) is connected to the lower bearing platform (213) of the vertical vibration isolator. The ball joint inverted pendulum (33) rotates circumferentially within a certain range to provide horizontal negative stiffness. Horizontal springs (32) are hung between the two corresponding side surfaces of the horizontal vibration isolation platform (3) and the upper bearing platform (211) of the vertical vibration isolator (2). The horizontal springs balancing the displacement in the x-axis direction and the horizontal springs balancing the displacement in the y-axis direction jointly provide horizontal positive stiffness. Quasi-zero stiffness passive vibration isolation is achieved by balancing the horizontal positive stiffness and the horizontal negative stiffness.

[0008] Include the following expressions:

[0009]

[0010] Where K is the dimensionless equivalent stiffness of the horizontal vibration isolator, x is the deformation of the horizontal spring, h is the height from the horizontal spring to the bottom of the ball joint pendulum, k is the total stiffness of the horizontal spring, m is the load mass, g is the acceleration of gravity, and H is the length of the ball joint pendulum.

[0011] The vertical vibration isolator (2) comprises a bearing mechanism (21), a vertical spring (22), a vertical negative stiffness mechanism (23), and a load adjustment mechanism (24), wherein the bearing mechanism (21) comprises an upper bearing platform (211), a connecting rod A (212), and a lower bearing platform (213), the upper bearing platform (211) and the lower bearing platform (213) are fixedly connected via the connecting rod A (212), the upper end of the vertical spring (22) is fixedly connected to the upper bearing platform (211), and the lower end is fixedly connected to the spring tray C (245), the vertical spring (22) is used to bear the load and provide positive stiffness in the vertical direction, and the vertical negative stiffness mechanism (23) can adjust the negative stiffness to achieve quasi-zero stiffness.

[0012] The vertical negative stiffness mechanism (23) comprises a guide rail (231), a slider (232), a rotating connecting rod (233), a support (234) and a lateral adjustment mechanism (235), and is substantially symmetrical. The guide rail (231) is fixedly connected to the support base plate (41) via a connecting rod B (236); the slider (232) can slide linearly along the guide rail (231); the rotating connecting rod (233) is rotatably connected to the slider (232) and the support (234) respectively; the support (234) is fixedly connected to the lower bearing platform (213) via a connecting rod C (237); the lateral adjustment mechanism adjusts the vertical negative stiffness by moving the slider (232) and changing the angle between the rotating connecting rod (233) and the horizontal plane.

[0013] The lateral adjustment mechanism (235) includes a lateral spring (2351), a screw rod A (2352), a screw rod B (2353), a spring tray A (2354) and a spring tray B (2355), wherein the two ends of the lateral spring (2351) are fixedly connected to the spring tray A (2354) and the spring tray B (2355); the screw rod A (2352) passes through the spring tray A (2354), the lateral spring (2351), the spring tray B (2355) and the slider (232) in sequence, and the other side passes through in the opposite direction in sequence; the spring tray A (2354) is threadedly connected to the screw rod A (2352) and fixedly connected to the screw rod B; the spring tray B (2355) is threadedly connected to the screw rod B (2353) and fixedly connected to the slider (232).

[0014] The load adjustment mechanism (24) includes an indicator (241), a worm (242), a turbine (243), a screw C (244) and a spring tray C (245), wherein the indicator (241) is fixedly connected to the side of the upper bearing platform (211), the screw C (244) passes through the supporting base plate (41) and is fixedly connected to the center of the turbine (243), and the spring tray C (245) is threadedly connected to the screw C (244). The spring tray C (245) moves up and down in the vertical direction through the worm and worm structure.

[0015] The support base (4) comprises a support base plate (41), a support side plate (42), a support leg (43) and a shell (44), wherein the support side plate (42) serves as a main frame, and the support base plate (41), the support leg (43) and the shell (44) are all fixedly connected to the support side plate (42); a connecting rod A (212) and a connecting rod C (237) pass through the support base plate (41), and the support leg (43) is placed on a horizontal ground.

[0016] The supporting side plate (42) is provided with a vertical through hole A (421), and the limiting rod (34) can swing slightly in the through hole A (421) to prevent the ball joint from swinging backward and becoming unstable; the outer shell is provided with a horizontal through hole B (441) and a through hole C (442), the worm (242) passes through the through hole B (441), and the indicator (241) can move slightly in the through hole C (442).

[0017] By adjusting the worm (242), the indicator (241) can be positioned at the center of the through hole C (442).

[0018] The technical effects of the present invention are as follows:

[0019] 1. This invention is suitable for ultra-low frequency vibration isolation of different loads. The vertical and horizontal stiffness can be adjusted according to the load mass to obtain quasi-zero characteristics, which greatly reduces the natural frequency of the vibration isolation platform and realizes ultra-low frequency vibration isolation.

[0020] 2. The present invention is provided with a vertical vibration isolator, which uses components such as a slider and a connecting rod to form a vertical negative stiffness mechanism. The negative stiffness is easily adjustable through a lateral adjustment mechanism, and is connected in parallel with a vertical spring to achieve quasi-zero stiffness.

[0021] 3. The present invention is provided with a horizontal vibration isolator, which realizes the quasi-zero characteristic in the horizontal direction by flexibly adjusting the positive stiffness of the horizontal spring and combining it with the inverted pendulum of the ball joint. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the structure of the quasi-zero stiffness passive vibration isolation platform of the present invention.

[0023] Figure 2 for Figure 1 Schematic diagram of the vertical vibration isolator structure in .

[0024] Figure 3 for Figure 2 Schematic diagram of the vertical negative stiffness mechanism structure.

[0025] Figure 4 for Figure 3 Schematic diagram of the lateral adjustment mechanism structure.

[0026] Figure 5 for Figure 1 Schematic diagram of the horizontal vibration isolator structure in .

[0027] Figure 6 for Figure 1 Schematic diagram of the support seat structure.

[0028] The reference numerals are listed as follows: 1-load platform; 2-vertical vibration isolator; 3-horizontal vibration isolator; 4-support seat; 22-vertical spring; 23-vertical negative stiffness mechanism; 211-upper bearing platform; 212-connecting rod; 213-lower bearing platform (211, 212, 213 constitute a bearing mechanism); 231-guide rail; 232-slider; 233-rotating connecting rod; 234-support; 235-lateral adjustment mechanism; 236-connecting rod B; 237-connecting rod C; 2351-lateral spring; 2352-screw A; 2353-screw B ; 2354-spring tray A; 2355-spring tray B; 241-indicator; 242-worm; 243-turbine; 244-stud C; 245-spring tray C (241, 242, 243, 244, 245 constitute a load adjustment mechanism); 31-horizontal vibration isolation platform; 311-vibration isolation pad; 32-horizontal spring; 33-ball joint inverted swing; 34-limiting rod; 41-support base plate; 42-support side plate; 43-support foot; 44-housing; 421-through hole A; 441-through hole B; 442-through hole C. DETAILED DESCRIPTION

[0029] Below is the attached figure ( Figures 1-6 ) and Examples illustrate the present invention.

[0030] Figure 1 Schematic diagram of the structure of the quasi-zero stiffness passive vibration isolation platform of the present invention. Figure 2 for Figure 1 Schematic diagram of the vertical vibration isolator structure in . Figure 3 for Figure 2 Schematic diagram of the vertical negative stiffness mechanism structure. Figure 4 for Figure 3 Schematic diagram of the lateral adjustment mechanism structure.

[0031] Figure 5 for Figure 1 Schematic diagram of the horizontal vibration isolator structure in . Figure 6 for Figure 1 Schematic diagram of the support structure in . Figures 1 to 6 As shown, the quasi-zero stiffness passive vibration isolation platform includes a vertical vibration isolator and a horizontal vibration isolator arranged below the load platform, both of which are located in a support seat, the vertical vibration isolator has a vertical negative stiffness mechanism, and the vertical negative stiffness mechanism has a lateral adjustment mechanism, the load platform is used to place the object to be isolated, the vertical vibration isolator and the horizontal vibration isolator are fixedly connected by a ball joint inverted pendulum, and the support seat is connected to the foundation. The upper end of the ball joint inverted pendulum (33) is connected to the horizontal vibration isolation platform (31) of the horizontal vibration isolator (3), and the lower end of the ball joint inverted pendulum (33) is connected to the lower bearing platform (213) of the vertical vibration isolator. The ball joint inverted pendulum (33) rotates circumferentially within a certain range to provide horizontal negative stiffness. Horizontal springs (32) are hung between the two corresponding side surfaces of the horizontal vibration isolation platform (3) and the upper bearing platform (211) of the vertical vibration isolator (2). The horizontal springs balancing the displacement in the x-axis direction and the horizontal springs balancing the displacement in the y-axis direction jointly provide horizontal positive stiffness. Quasi-zero stiffness passive vibration isolation is achieved by balancing the horizontal positive stiffness and the horizontal negative stiffness.

[0032] Include the following expressions:

[0033]

[0034] Where K is the dimensionless equivalent stiffness of the horizontal vibration isolator, x is the deformation of the horizontal spring, h is the height from the horizontal spring to the bottom of the ball joint pendulum, k is the total stiffness of the horizontal spring, m is the load mass, g is the acceleration of gravity, and H is the length of the ball joint pendulum.

[0035] The vertical vibration isolator (2) comprises a bearing mechanism (21), a vertical spring (22), a vertical negative stiffness mechanism (23), and a load adjustment mechanism (24), wherein the bearing mechanism (21) comprises an upper bearing platform (211), a connecting rod A (212), and a lower bearing platform (213), the upper bearing platform (211) and the lower bearing platform (213) are fixedly connected via the connecting rod A (212), the upper end of the vertical spring (22) is fixedly connected to the upper bearing platform (211), and the lower end is fixedly connected to the spring tray C (245), the vertical spring (22) is used to bear the load and provide positive stiffness in the vertical direction, and the vertical negative stiffness mechanism (23) can adjust the negative stiffness to achieve quasi-zero stiffness. The vertical negative stiffness mechanism (23) includes a guide rail (231), a slider (232), a rotating connecting rod (233), a support (234) and a lateral adjustment mechanism (235), and is substantially symmetrical. The guide rail (231) is fixedly connected to the support base plate (41) via a connecting rod B (236); the slider (232) can slide linearly along the guide rail (231); the rotating connecting rod (233) is rotatably connected to the slider (232) and the support (234); and the support (234) is fixedly connected to the lower bearing platform (213) via a connecting rod C (237). The lateral adjustment mechanism adjusts the vertical negative stiffness by moving the slider (232) and changing the angle between the rotating connecting rod (233) and the horizontal plane.

[0036] The lateral adjustment mechanism (235) includes a lateral spring (2351), a screw rod A (2352), a screw rod B (2353), a spring tray A (2354) and a spring tray B (2355), wherein the two ends of the lateral spring (2351) are fixedly connected to the spring tray A (2354) and the spring tray B (2355); the screw rod A (2352) passes through the spring tray A (2354), the lateral spring (2351), the spring tray B (2355) and the slider (232) in sequence, and the other side passes through in the opposite direction in sequence; the spring tray A (2354) is threadedly connected to the screw rod A (2352) and fixedly connected to the screw rod B; the spring tray B (2355) is threadedly connected to the screw rod B (2353) and fixedly connected to the slider (232). The load adjustment mechanism (24) includes an indicator (241), a worm (242), a turbine (243), a screw C (244) and a spring tray C (245), wherein the indicator (241) is fixedly connected to the side of the upper bearing platform (211), the screw C (244) passes through the supporting base plate (41) and is fixedly connected to the center of the turbine (243), and the spring tray C (245) is threadedly connected to the screw C (244). The spring tray C (245) moves up and down in the vertical direction through the worm and worm structure.

[0037] The support seat (4) includes a support base plate (41), a support side plate (42), a support foot (43) and a shell (44), wherein the support side plate (42) is a main frame, and the support base plate (41), the support foot (43) and the shell (44) are all fixedly connected to the support side plate (42); the connecting rod A (212) and the connecting rod C (237) pass through the support base plate (41), and the support foot (43) is placed on a horizontal ground. The support side plate (42) is provided with a vertical through hole A (421), and the limit rod (34) can swing slightly in the through hole A (421) to prevent the ball joint from swinging backward and becoming unstable; the shell is provided with a horizontal through hole B (441) and a through hole C (442), the worm (242) passes through the through hole B (441), and the indicator (241) can move slightly in the through hole C (442). By adjusting the worm (242), the indicator (241) can be positioned at the center of the through hole C (442).

[0038] The present invention discloses a quasi-zero stiffness passive vibration isolation platform, comprising a load platform, a support base, a vertical vibration isolator, and a horizontal vibration isolator. The vertical vibration isolator includes a vertical negative stiffness mechanism with adjustable quasi-zero stiffness and a vertical spring, while the horizontal vibration isolator includes a horizontal spring with adjustable quasi-zero stiffness and a ball joint inverted pendulum. The present invention can flexibly adjust the horizontal positive stiffness and vertical negative stiffness according to the load mass, resulting in a system with quasi-zero stiffness characteristics, thereby achieving ultra-low frequency passive vibration isolation.

[0039] like Figure 1 As shown, the quasi-zero stiffness passive vibration isolation platform of the present invention comprises a load platform (1), a vertical vibration isolator (2), a horizontal vibration isolator (3) and a support seat (4). It is characterized in that the load platform (1) is placed on the upper layer of the horizontal vibration isolator (3) for placing the object to be isolated; the vertical vibration isolator (2) and the horizontal vibration isolator (3) are fixedly connected by a ball joint inverted pendulum (34); and the support seat is connected to the foundation. The present invention can flexibly adjust the horizontal positive stiffness and the vertical negative stiffness according to the load mass, so that the system has a quasi-zero stiffness characteristic and realizes ultra-low frequency passive vibration isolation.

[0040] like Figure 2 As shown, the vertical vibration isolator (2) includes a bearing mechanism (21), a vertical spring (22), a vertical negative stiffness mechanism (23), and a load adjustment mechanism (24), wherein the bearing mechanism (21) includes an upper bearing platform (211), a connecting rod A (212), and a lower bearing platform (213), and the upper bearing platform (211) and the lower bearing platform (213) are fixedly connected via the connecting rod A (212). The upper end of the vertical spring (22) is fixedly connected to the upper bearing platform (211), and the lower end is fixedly connected to the spring tray C (245). The vertical spring (22) is used to bear the load and provide positive stiffness in the vertical direction. The vertical negative stiffness mechanism (23) can adjust the negative stiffness to achieve quasi-zero stiffness.

[0041] like Figure 3As shown, the vertical negative stiffness mechanism (23) includes a guide rail (231), a slider (232), a rotating connecting rod (233), a support (234) and a lateral adjustment mechanism (235), which are basically symmetrical. The guide rail (231) is fixedly connected to the support base (41) through a connecting rod B (236); the slider (232) can slide linearly along the guide rail (231); the rotating connecting rod (233) is rotatably connected to the slider (232) and the support (234); the support (234) is fixedly connected to the lower bearing platform (213) through a connecting rod C (237). The lateral adjustment mechanism adjusts the vertical negative stiffness by moving the slider (232) and changing the angle between the rotating connecting rod (233) and the horizontal plane.

[0042] The load adjustment mechanism (24) includes an indicator (241), a worm (242), a turbine (243), a screw C (244) and a spring tray C (245), wherein the indicator (241) is fixedly connected to the side of the upper bearing platform (211), the screw C (244) passes through the supporting base plate (41) and is fixedly connected to the center of the turbine (243), and the spring tray C (245) is threadedly connected to the screw C (244). The spring tray C (245) moves up and down in the vertical direction through the worm and worm structure.

[0043] like Figure 4 As shown, the lateral adjustment mechanism (235) includes a lateral spring (2351), a screw rod A (2352), a screw rod B (2353), a spring tray A (2354) and a spring tray B (2355), wherein both ends of the lateral spring (2351) are fixedly connected to the spring tray A (2354) and the spring tray B (2355); the screw rod A (2352) passes through the spring tray A (2354), the lateral spring (2351), the spring tray B (2355) and the slider (232) in sequence, and the other side passes through in the opposite direction in sequence; the spring tray A (2354) is threadedly connected to the screw rod A (2352) and fixedly connected to the screw rod B; the spring tray B (2355) is threadedly connected to the screw rod B (2353) and fixedly connected to the slider (232).

[0044] like Figure 5 As shown, the horizontal vibration isolator (3) includes a horizontal vibration isolation platform (31), a horizontal spring (32), a ball joint pendulum (33) and a limit rod (34). The upper surface of the horizontal vibration isolation platform (31) is installed with a vibration isolation pad (311) to prevent the load from tilting; the upper end of the ball joint pendulum (33) is connected to the horizontal vibration isolation platform (31), and the lower end is connected to the lower bearing platform (213), and rotates circumferentially within a certain range to provide horizontal negative stiffness; the horizontal vibration isolation platform (31) and the upper bearing platform (211) are both hung with horizontal springs (32) on each side to provide horizontal positive stiffness. By selecting horizontal springs with appropriate stiffness, the quasi-zero stiffness of the horizontal vibration isolator can be achieved.

[0045] like Figure 6 As shown, the support seat (4) includes a support base plate (41), a support side plate (42), a support foot (43) and a shell (44). The support side plate (42) is the main frame, and the support base plate (41), the support foot (43) and the shell (44) are all fixedly connected to the support side plate (42); the connecting rod A (212) and the connecting rod C (237) pass through the support base plate (41); and the support foot (43) is placed on the horizontal ground. The support side plate (42) is provided with a vertical through hole A (421), and the limit rod (34) can swing slightly in the through hole A (421) to prevent the ball joint from swinging backward and becoming unstable; the shell is provided with a horizontal through hole B (441) and a through hole C (442), the worm (242) passes through the through hole B (441), and the indicator (241) can move slightly in the through hole C (442). By adjusting the worm (242), the indicator (241) can be positioned at the center of the through hole C (442).

[0046] A load with a mass of m is placed on the load platform. According to the force transmission effect, the horizontal vibration isolation platform (31), the lower bearing platform (213), the connecting rod A (212), the upper bearing platform (211), and the indicator (241) all move downward. If the load mass is too small, the indicator (241) is located above the center of the through hole C (442); otherwise, it is located below the center.

[0047] For a static load m, the stiffness is k z The compression amount Δx of the vertical spring (22) is constant, which is The worm (243) rotates, and the worm-gear structure transmits the motion to the screw C (244). Furthermore, the rotation of the screw C causes the spring tray C (245) to move up and down in the vertical direction. Since the compression amount Δx of the vertical spring (22) is constant, the vertical spring (22), the upper bearing platform (211), and the indicator (241) move up and down accordingly. When the indicator (241) is located at the center of the through hole C (422), it means that the load size is appropriate.

[0048] By rotating the screw rod A (2352), the spring tray A (2354) and the screw rod B (2353) move left and right in the horizontal direction, and further transmit the movement to the spring tray B (2355) and the slider (232). The movement of the slider (232) along the guide rail (231) changes the angle between the rotating connecting rod (233) and the horizontal plane, thereby causing the support (234) to move vertically. The force is transmitted to the lower bearing platform (213) through the connecting rod C (237), thereby realizing the adjustment of the negative stiffness.

[0049] The dimensionless equivalent stiffness K of the horizontal vibration isolator is: Where x is the horizontal spring deformation, h is the height from the horizontal spring to the bottom of the ball joint pendulum, k is the total stiffness of the horizontal spring, m is the load mass, g is the acceleration of gravity, and H is the length of the ball joint pendulum. By designing reasonable structural parameters h and H, the stiffness k of the horizontal spring is adjusted to meet Quasi-zero stiffness can be achieved.

[0050] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "circumferential", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the present invention.

[0051] Any content not described in detail in this specification is prior art known to those skilled in the art. It should be noted that the above description is intended to help those skilled in the art understand the present invention, but does not limit the scope of protection of the present invention. Any equivalent substitution, modification, improvement, and / or simplification of the above description that does not depart from the essence of the present invention shall fall within the scope of protection of the present invention.

Claims

1. Quasi-zero stiffness passive vibration isolation table, characterized by: The vertical vibration isolator and the horizontal vibration isolator are arranged below the load platform. The vertical vibration isolator and the horizontal vibration isolator are both located in the support seat. The vertical vibration isolator has a vertical negative stiffness mechanism, and the vertical negative stiffness mechanism has a lateral adjustment mechanism. The load platform is used to place the object to be isolated. The vertical vibration isolator and the horizontal vibration isolator are fixedly connected by a ball joint in an inverted pendulum manner. The support seat is connected to the foundation. The upper end of the ball joint inverted pendulum (33) is connected to the horizontal vibration isolation platform (31) of the horizontal vibration isolator (3), and the lower end of the ball joint inverted pendulum (33) is connected to the lower bearing platform (213) of the vertical vibration isolator. The ball joint inverted pendulum (33) rotates circumferentially within a certain range to provide horizontal negative stiffness. Horizontal springs (32) are hung between the two corresponding side surfaces of the horizontal vibration isolation platform (3) and the upper bearing platform (211) of the vertical vibration isolator (2). The horizontal springs balancing the displacement in the x-axis direction and the horizontal springs balancing the displacement in the y-axis direction jointly provide horizontal positive stiffness. Quasi-zero stiffness passive vibration isolation is achieved by balancing the horizontal positive stiffness and the horizontal negative stiffness. The following expression is used to determine the Quasi-zero stiffness is achieved when: , Where K is the dimensionless equivalent stiffness of the horizontal vibration isolator, x is the deformation of the horizontal spring, h is the height from the horizontal spring to the bottom of the ball joint pendulum, k is the total stiffness of the horizontal spring, m is the load mass, g is the acceleration of gravity, and H is the length of the ball joint pendulum.

2. The quasi-zero stiffness passive vibration isolation platform according to claim 1, characterized in that: The vertical vibration isolator (2) comprises a bearing mechanism (21), a vertical spring (22), a vertical negative stiffness mechanism (23), and a load adjustment mechanism (24), wherein the bearing mechanism (21) comprises an upper bearing platform (211), a connecting rod A (212), and a lower bearing platform (213), the upper bearing platform (211) and the lower bearing platform (213) are fixedly connected via the connecting rod A (212), the upper end of the vertical spring (22) is fixedly connected to the upper bearing platform (211), and the lower end is fixedly connected to the spring tray C (245), the vertical spring (22) is used to bear the load and provide positive stiffness in the vertical direction, and the vertical negative stiffness mechanism (23) can adjust the negative stiffness to achieve quasi-zero stiffness.

3. The quasi-zero stiffness passive vibration isolation platform according to claim 2, characterized in that: The vertical negative stiffness mechanism (23) comprises a guide rail (231), a slider (232), a rotating connecting rod (233), a support (234) and a lateral adjustment mechanism (235), and is substantially symmetrical on the left and right sides. The guide rail (231) is fixedly connected to the support base plate (41) via a connecting rod B (236); the slider (232) can slide linearly along the guide rail (231); the rotating connecting rod (233) is rotatably connected to the slider (232) and the support (234) respectively; the support (234) is fixedly connected to the lower bearing platform (213) via a connecting rod C (237); the lateral adjustment mechanism adjusts the vertical negative stiffness by moving the slider (232) and changing the angle between the rotating connecting rod (233) and the horizontal plane.

4. The quasi-zero stiffness passive vibration isolation platform according to claim 3, characterized in that: The lateral adjustment mechanism (235) comprises a lateral spring (2351), a screw rod A (2352), a screw rod B (2353), a spring tray A (2354) and a spring tray B (2355), wherein both ends of the lateral spring (2351) are fixedly connected to the spring tray A (2354) and the spring tray B (2355); the screw rod A (2352) sequentially passes through the spring tray A (2354), the lateral spring (2351), the spring tray B (2355) and the slider (232), and the other side passes through in the opposite direction in sequence; the spring tray A (2354) is threadedly connected to the screw rod A (2352) and fixedly connected to the screw rod B; the spring tray B (2355) is threadedly connected to the screw rod B (2353) and fixedly connected to the slider (232).

5. The quasi-zero stiffness passive vibration isolation platform according to claim 2, characterized in that: The load adjustment mechanism (24) comprises an indicator (241), a worm (242), a turbine (243), a screw C (244) and a spring tray C (245), wherein the indicator (241) is fixedly connected to the side of the upper bearing platform (211), the screw C (244) passes through the supporting base plate (41) and is fixedly connected to the center of the turbine (243), and the spring tray C (245) is threadedly connected to the screw C (244), and the spring tray C (245) moves up and down in the vertical direction through the turbine and worm structure.

6. The quasi-zero stiffness passive vibration isolation platform according to claim 1, characterized in that: The support base (4) comprises a support base plate (41), a support side plate (42), a support foot (43) and a shell (44), wherein the support side plate (42) serves as a main frame, and the support base plate (41), the support foot (43) and the shell (44) are all fixedly connected to the support side plate (42); the connecting rod A (212) and the connecting rod C (237) pass through the support base plate (41), and the support foot (43) is placed on a horizontal ground.

7. The quasi-zero stiffness passive vibration isolation platform according to claim 6, characterized in that: The supporting side plate (42) is provided with a vertical through hole A (421), and the limiting rod (34) can swing slightly in the through hole A (421) to prevent the ball joint from swinging backward and becoming unstable; the housing is provided with a horizontal through hole B (441) and a through hole C (442), the worm (242) passes through the through hole B (441), and the indicator (241) can move slightly in the through hole C (442).

8. The quasi-zero stiffness passive vibration isolation platform according to claim 5, characterized in that: By adjusting the worm (242), the indicator (241) can be positioned at the center of the through hole C (442).

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