A double-layer six-degree-of-freedom ultra-low-frequency quasi-zero stiffness vibration isolation platform

Abstract

The present invention provides a double-layer, six-degree-of-freedom, ultra-low-frequency, quasi-zero-stiffness vibration isolation platform, comprising a base, a top plate, a support block, and vibration isolation legs. The top of the base is equipped with four vibration isolation legs via ball joints, the other ends of which are connected to the lower sides of the support block via Hooke's hinges. The bottom of the top plate is also equipped with four vibration isolation legs via ball joints, the other ends of which are connected to the upper sides of the support block via Hooke's hinges. A position sensor A and an acceleration sensor A are also installed at the bottom of the top plate, and a controller is also installed at the top of the base. The system of the present invention can achieve vibration control from 0.1Hz to 250Hz, has a wide vibration isolation band, can achieve six-degree-of-freedom vibration isolation, and has precise positioning. It can be adapted to various types of precision instruments, has a maximum load capacity of 1000kg, and has a wide range of applications and strong versatility.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor special devices, in particular to a double-layer six-degree-of-freedom ultra-low-frequency quasi-zero-rigidity vibration isolation platform. Background Art

[0002] At present, the semiconductor industry is developing rapidly. The precision requirements of semiconductor production equipment are getting higher and higher. The equipment is becoming more and more sensitive to environmental requirements such as micro-vibration. A small amount of micro-vibration will reduce the output yield of the equipment or even cause the equipment to malfunction. Therefore, isolation of micro-vibration is becoming more and more important.

[0003] To address these issues, researchers have recently discovered novel vibration isolation methods based on nonlinear dynamics theory—quasi-zero-stiffness isolators. These isolators exhibit high static stiffness and low dynamic stiffness. Specifically, when the system is subjected to static loads, the isolator exhibits relatively high system stiffness, providing sufficient support. When the system is subjected to dynamic loads, the isolator exhibits lower stiffness, increasing the isolation bandwidth and enabling low- and ultra-low-frequency vibration isolation. However, most current nonlinear isolators based on quasi-zero-stiffness theory can only achieve vibration reduction for specific controlled objects and are unable to isolate diverse objects. Furthermore, existing quasi-zero-stiffness isolators have a narrow low-stiffness displacement range. As displacement increases, the stiffness and nonlinearity increase significantly, increasing the isolator's initial isolation frequency, narrowing the isolation frequency band, and degrading low-frequency vibration isolation performance, thus limiting the applicability of quasi-zero-stiffness isolators. Furthermore, existing quasi-zero-stiffness vibration isolation methods primarily focus on single-axis vibration isolation, while research on multi-degree-of-freedom quasi-zero-stiffness vibration isolation is relatively rare. Summary of the Invention

[0004] The purpose of the present invention is to provide a double-layer six-degree-of-freedom ultra-low frequency quasi-zero stiffness vibration isolation platform to solve the problems existing in the above-mentioned background technology.

[0005] The technical solution of the present invention is achieved as follows: a double-layer six-degree-of-freedom ultra-low frequency quasi-zero stiffness vibration isolation platform, including a base, a top plate, a support block and a vibration isolation leg, the top of the base is equipped with four vibration isolation legs through a ball joint, the other ends of the four vibration isolation legs are respectively connected to the lower parts of the four sides of the support block through a Hooke's hinge, the bottom of the top plate is also equipped with four vibration isolation legs through a ball joint, the other ends of the four vibration isolation legs are respectively connected to the upper parts of the four sides of the support block through a Hooke's hinge, the vibration isolation leg includes an outer shell and a push rod, a piston is installed inside the outer shell, a baffle is installed inside the outer shell and above the piston, a first air chamber is formed between the piston and the inner side of the bottom of the outer shell, a second air chamber is formed between the piston and the baffle, and the push rod penetrates vertically Through the top of the outer shell and the baffle, the bottom of the push rod is vertically connected and fixed to the middle of the top of the piston. A permanent magnet is installed at the bottom of the piston, and an electromagnetic coil is installed correspondingly below the permanent magnet. Telescopic rods are installed on both sides of the bottom of the electromagnetic coil. A metal spring A is set between the outside of the telescopic rod, the bottom of the electromagnetic coil and the inside of the bottom of the outer shell. A support plate is vertically installed on the outside of the push rod and above the baffle. Metal springs B are installed on the left and right sides of the push rod, between the inside of the top of the outer shell and the top of the support plate. Metal springs C are installed on the left and right sides of the push rod, between the bottom of the support plate and the top of the baffle. A position sensor A and an acceleration sensor A are also installed at the bottom of the top plate, and a controller is also installed on the top of the base.

[0006] Furthermore, the base and the top plate are both made of stainless steel plates into a rectangular structure.

[0007] Furthermore, the ball joints are arranged in a diamond shape of the same size at the top of the base and the bottom of the top plate.

[0008] Furthermore, the support block is made of stainless steel and has a cubic structure.

[0009] Furthermore, an air intake pipe A is installed on one side of the first air chamber, and a pneumatic valve A is installed on the air intake pipe A.

[0010] Furthermore, an air intake pipe B is installed on one side of the second air chamber, and a pneumatic valve B is installed on the air intake pipe B.

[0011] Furthermore, a position sensor B and an acceleration sensor B are installed at the bottom of the support plate.

[0012] Furthermore, a linear bearing is installed between the push rod and the top of the shell.

[0013] Furthermore, a sealing ring is installed between the push rod and the baffle.

[0014] Furthermore, the controller is connected to the position sensor A, the acceleration sensor A, the position sensor B, the acceleration sensor B and the electromagnetic coil through cables.

[0015] The beneficial effects of the present invention are:

[0016] The present invention achieves the load-bearing requirements of different precision instruments by controlling the air pressure of the first air chamber. At the same time, a positive and negative stiffness parallel system is formed by the first air chamber and the second air chamber. The system achieves quasi-zero stiffness when in static balance, has the characteristics of high static and low dynamic stiffness, and can meet the stiffness requirements of different precision instruments through air pressure adjustment.

[0017] The present invention adopts a double-layer series structure design. The four diamond-shaped vibration isolation legs in the upper structure and the four diamond-shaped vibration isolation legs in the lower structure form a series structure. When targeting high-frequency vibration sources, the metal springs B and C in the upper structure are connected in parallel to achieve the first high-frequency vibration reduction, and the metal spring A achieves the second high-frequency vibration reduction. The metal springs B and C in the lower structure are connected in parallel to achieve the third high-frequency vibration reduction, and the metal spring A achieves the fourth high-frequency vibration reduction. Through the four vibration reductions, higher vibration frequencies can be reduced. When targeting low-frequency vibration sources, two electromagnetic drive vibration reductions are achieved through the electromagnetic coils in the upper structure and the lower structure, which can reduce the vibration of lower frequencies.

[0018] The system of the present invention can achieve vibration control of 0.1Hz~250Hz, has a wide vibration isolation band, can achieve six-degree-of-freedom vibration isolation, and has precise positioning. It can be adapted to different types of precision instruments, has a maximum load-bearing capacity of 1000kg, has a wide range of applications, and is highly versatile. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the present invention.

[0020] Figure 2 It is a structural schematic diagram of the vibration isolation leg of the present invention.

[0021] In the figure, 1-base, 2-top plate, 3-vibration isolation leg, 301-housing, 302-push rod, 303-piston, 304-baffle, 305-first air chamber, 306-second air chamber, 307-permanent magnet, 308-electromagnetic coil, 309-telescopic rod, 310-metal spring A, 311-support plate, 312-metal spring B, 313-metal spring C, 314-inlet pipe A, 315-pneumatic valve A, 316-inlet pipe B, 317-pneumatic valve B, 318-position sensor B, 319-acceleration sensor C, 320-linear bearing, 321-sealing ring, 4-support block, 5-Hook's hinge, 6-ball joint, 7-position sensor A, 8-speed sensor A, 9-controller. DETAILED DESCRIPTION

[0022] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] like Figure 1-2 As shown, a double-layer six-degree-of-freedom ultra-low frequency quasi-zero stiffness vibration isolation platform includes a base, a top plate, a support block and a vibration isolation leg. Four vibration isolation legs are installed on the top of the base through a ball joint, and the other ends of the four vibration isolation legs are respectively connected to the lower parts of the four sides of the support block through Hooke's hinges. Four vibration isolation legs are also installed on the bottom of the top plate through a ball joint, and the other ends of the four vibration isolation legs are respectively connected to the upper parts of the four sides of the support block through Hooke's hinges. The vibration isolation leg includes a shell and a push rod, a piston is installed inside the shell, and a baffle is installed inside the shell and above the piston. A first air chamber is formed between the piston and the inner side of the bottom of the shell, and a second air chamber is formed between the piston and the baffle. The push rod vertically passes through the top of the shell and the baffle Plate, the bottom of the push rod is vertically connected and fixed to the middle of the top of the piston, a permanent magnet is installed at the bottom of the piston, an electromagnetic coil is installed correspondingly just below the permanent magnet, telescopic rods are respectively installed on both sides of the bottom of the electromagnetic coil, a metal spring A is set between the outside of the telescopic rod, the bottom of the electromagnetic coil and the inner side of the bottom of the shell, a support plate is vertically installed on the outside of the push rod and above the baffle, metal springs B are respectively installed on the left and right sides of the push rod, between the inner side of the top of the shell and the top of the support plate, metal springs C are respectively installed on the left and right sides of the push rod, between the bottom of the support plate and the top of the baffle, a position sensor A and an acceleration sensor A are also installed at the bottom of the top plate, and a controller is also installed on the top of the base.

[0024] The base and the top plate are both made of stainless steel plates into a rectangular structure.

[0025] The ball joints are arranged in a diamond shape of the same size at the top of the base and the bottom of the top plate.

[0026] The support block is made of stainless steel and has a cubic structure.

[0027] An air intake pipe A is installed on one side of the first air chamber, and a pneumatic valve A is installed on the air intake pipe A.

[0028] An air intake pipe B is installed on one side of the second air chamber, and a pneumatic valve B is installed on the air intake pipe B.

[0029] A position sensor B and an acceleration sensor B are installed on the bottom of the support plate.

[0030] A linear bearing is also installed between the push rod and the top of the shell.

[0031] A sealing ring is installed between the push rod and the baffle.

[0032] The controller is connected to the position sensor A, the acceleration sensor A, the position sensor B, the acceleration sensor B and the electromagnetic coil through cables.

[0033] During installation, the precision instrument is installed on the top plate 1. The weight of the precision instrument is mainly borne by the first air chamber 305 of the vibration isolation leg 3, and the air intake of the air intake pipe A314 is controlled by the pneumatic valve A315 to adjust the bearing capacity and positive stiffness of the first air chamber 305 to meet the bearing requirements of different precision instruments. At the same time, the air intake of the air intake pipe B316 is controlled by the pneumatic valve B317 to adjust the negative stiffness of the second air chamber. By designing the positive and negative stiffness of the first air chamber 305 and the second air chamber 306 in parallel, the system can reach a quasi-zero stiffness state when the system is statically balanced. At this time, the metal spring B and the metal spring C are both not subjected to force.

[0034] During operation, the precision instrument generates vibrations, and the vibration signals of the top plate 2 are collected through the position sensor A7 and the acceleration sensor A8. The position sensor B and the acceleration sensor B of the vibration isolation leg 3 in the upper structure collect the vibration signals of the top plate 2 to the push rod 302. The position sensor B and the acceleration sensor B of the vibration isolation leg 3 in the lower structure collect the vibration signals of the support block 4 to the push rod 302, and then the vibration signals are transmitted to the controller 9. During high-frequency vibration, in the upper structure: the metal spring B312 and the metal spring C313 are connected in parallel to achieve the first high-frequency vibration reduction. At the same time, the controller 9 controls the magnetic field strength and direction of the electromagnetic coil 308 to apply a reaction force to the movement of the permanent magnet 307. The electromagnetic coil 308 moves up and down, and the metal spring A309 below achieves the second high-frequency vibration reduction. In the lower structure: the metal spring B312 and the metal spring C313 are connected in parallel to achieve the third high-frequency vibration reduction. At the same time, the controller 9 controls the magnetic field strength and direction of the electromagnetic coil 308 to apply a reaction force to the movement of the permanent magnet 307. The electromagnetic coil 308 moves up and down, and the metal spring A309 below achieves the fourth high-frequency vibration reduction. During low-frequency vibration, in the upper structure: the magnetic field strength and direction of the electromagnetic coil 308 are controlled by the controller 9 to achieve the first low-frequency electromagnetic drive vibration reduction. In the lower structure: the magnetic field strength and direction of the electromagnetic coil 308 are controlled by the controller 9 to achieve the second low-frequency electromagnetic drive vibration reduction.

[0035] In addition, the eight double-layer vibration-damping legs 3 of the vibration isolation platform of the present invention can be driven independently, and can achieve six free vibration isolations: up and down, front and back, left and right, around the X axis, around the Y axis, and around the Z axis.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A double-layer six-degree-of-freedom ultra-low frequency quasi-zero stiffness vibration isolation platform, comprising a base, a top plate, a support block and vibration isolation legs, characterized in that: Four vibration isolation legs are installed on the top of the base through a ball joint, and the other ends of the four vibration isolation legs are connected to the lower parts of the four sides of the support block through a Hooke's hinge. Four vibration isolation legs are also installed on the bottom of the top plate through a ball joint, and the other ends of the four vibration isolation legs are connected to the upper parts of the four sides of the support block through a Hooke's hinge. The vibration isolation legs include an outer shell and a push rod, a piston is installed inside the outer shell, a baffle is installed inside the outer shell and above the piston, a first air chamber is formed between the piston and the inner side of the bottom of the outer shell, an air inlet pipe A is installed on one side of the first air chamber, a pneumatic valve A is installed on the air inlet pipe A, a second air chamber is formed between the piston and the baffle, an air inlet pipe B is installed on one side of the second air chamber, and a pneumatic valve B is installed on the air inlet pipe B. The push rod passes vertically through the top of the shell and the baffle, the bottom of the push rod is vertically connected and fixed to the middle of the top of the piston, a permanent magnet is installed at the bottom of the piston, an electromagnetic coil is installed correspondingly just below the permanent magnet, telescopic rods are installed on both sides of the bottom of the electromagnetic coil, a metal spring A is set between the outside of the telescopic rod, the bottom of the electromagnetic coil and the inside of the bottom of the shell, a support plate is vertically installed on the outside of the push rod and above the baffle, metal springs B are installed on the left and right sides of the push rod, between the inside of the top of the shell and the top of the support plate, metal springs C are installed on the left and right sides of the push rod, between the bottom of the support plate and the top of the baffle, a position sensor A and an acceleration sensor A are also installed at the bottom of the top plate, and a controller is also installed on the top of the base; Precision instruments are mounted on the top plate. The weight of the precision instruments is mainly borne by the first air chamber of the vibration isolation leg. The air intake of the air intake pipe A is controlled by pneumatic valve A to adjust the bearing capacity and positive stiffness of the first air chamber to meet the bearing requirements of different precision instruments. At the same time, the air intake of the air intake pipe B is controlled by pneumatic valve B to adjust the negative stiffness of the second air chamber. By designing the positive and negative stiffness of the first and second air chambers in parallel, the system can achieve a quasi-zero stiffness state when the system is statically balanced. At this time, both metal springs B and C are not subjected to stress. The precision instrument generates vibration, and the top plate vibration signal is collected through the position sensor A and the acceleration sensor A. The position sensor B and the acceleration sensor B of the vibration isolation leg in the upper structure collect the vibration signal of the top plate to the push rod. The position sensor B and the acceleration sensor B of the vibration isolation leg in the lower structure collect the vibration signal of the support block to the push rod, and then the vibration signal is transmitted to the controller; when the high-frequency vibration source is used, in the upper structure: the metal spring B and the metal spring C are connected in parallel to achieve the first high-frequency vibration reduction. At the same time, the controller controls the magnetic field strength and direction of the electromagnetic coil to apply a reaction force to the movement of the permanent magnet. When the permanent magnet moves downward, the metal spring A below realizes the second high-frequency vibration reduction. In the lower structure, the metal spring B and the metal spring C are connected in parallel to realize the third high-frequency vibration reduction. At the same time, the controller controls the magnetic field strength and direction of the electromagnetic coil to exert a reaction force on the movement of the permanent magnet. The electromagnetic coil moves up and down, and the metal spring A below realizes the fourth high-frequency vibration reduction. During low-frequency vibration, in the upper structure, the magnetic field strength and direction of the electromagnetic coil are controlled by the controller to realize the first low-frequency electromagnetic drive vibration reduction. In the lower structure, the magnetic field strength and direction of the electromagnetic coil are controlled by the controller to realize the second low-frequency electromagnetic drive vibration reduction.

2. A double-layer six-degree-of-freedom ultra-low-frequency quasi-zero stiffness vibration isolation platform according to claim 1, characterized in that: The base and the top plate are both made of stainless steel plates into a rectangular structure.

3. The double-layer six-degree-of-freedom ultra-low-frequency quasi-zero stiffness vibration isolation platform according to claim 1, characterized in that: The ball joints are arranged in a diamond shape of the same size at the top of the base and the bottom of the top plate.

4. The double-layer six-degree-of-freedom ultra-low-frequency quasi-zero stiffness vibration isolation platform according to claim 1, characterized in that: The support block is made of stainless steel and has a cubic structure.

5. The double-layer six-degree-of-freedom ultra-low-frequency quasi-zero stiffness vibration isolation platform according to claim 1, characterized in that: A position sensor B and an acceleration sensor B are installed on the bottom of the support plate.

6. The double-layer six-degree-of-freedom ultra-low-frequency quasi-zero stiffness vibration isolation platform according to claim 1, characterized in that: A linear bearing is also installed between the push rod and the top of the shell.

7. The double-layer six-degree-of-freedom ultra-low-frequency quasi-zero stiffness vibration isolation platform according to claim 1, characterized in that: A sealing ring is installed between the push rod and the baffle.

8. The double-layer six-degree-of-freedom ultra-low-frequency quasi-zero stiffness vibration isolation platform according to claim 1, characterized in that: The controller is connected to the position sensor A, the acceleration sensor A, the position sensor B, the acceleration sensor B and the electromagnetic coil through cables.

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