A quasi-zero stiffness six-degree-of-freedom vibration isolation platform

Abstract

The present application provides a kind of quasi-zero stiffness six-degree-of-freedom vibration isolation platform, including base, leg and top plate, the leg is three, the leg two ends are connected with the top of base, the bottom of top plate respectively through spherical hinge, the spherical hinge on the base, top plate is equilateral triangle distribution of same size, the leg is connected with the spherical hinge of top plate bottom in turn and right oblique, the bottom of top plate is also installed with position sensor and acceleration sensor, the top of base is also installed with controller.The present application system can realize 0.1Hz~200Hz vibration control, vibration isolation bandwidth, can realize six-degree-of-freedom vibration isolation, and positioning is accurate, can be adapted to different models of precision instrument, maximum load can reach 1000kg, wide range of application, strong versatility.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor special devices, and particularly relates to a quasi-zero stiffness six-degree-of-freedom vibration isolation platform. BACKGROUND

[0002] At present, the semiconductor industry develops rapidly, the precision requirement of semiconductor production equipment is higher and higher, and the equipment is more and more sensitive to the environment such as micro-vibration. A little micro-vibration will reduce the yield of the equipment, and even make the equipment unable to work normally. Therefore, the isolation of micro-vibration becomes more and more important.

[0003] In order to solve the above problems, in recent years, researchers have found some novel vibration isolation methods based on nonlinear dynamics theory-quasi-zero stiffness vibration isolator. The vibration isolator has the characteristics of high static and low dynamic in system stiffness, that is, when the system bears static load, the vibration isolator has relatively high system stiffness, which can provide sufficient supporting force; when the system bears dynamic load, the vibration isolator has relatively low system stiffness, which increases the vibration isolation frequency width, realizes low frequency and ultra-low frequency vibration isolation. However, most of the nonlinear vibration isolators based on quasi-zero stiffness theory can only realize the vibration reduction of specific controlled objects, and cannot meet the vibration isolation of different objects. In addition, the low stiffness displacement interval of the existing quasi-zero stiffness vibration isolator is relatively narrow, and the stiffness increases obviously with the increase of displacement, the nonlinearity is obviously enhanced, the initial vibration isolation frequency of the vibration isolator is increased, the vibration isolation frequency band is narrowed, and the low frequency vibration isolation performance is decreased, thereby affecting the application range of the quasi-zero stiffness vibration isolator. In addition, most of the existing quasi-zero stiffness vibration isolation methods focus on one-way vibration isolation, and the research on multi-degree-of-freedom quasi-zero stiffness vibration isolation is still relatively rare. SUMMARY

[0004] The present application aims to provide a quasi-zero stiffness six-degree-of-freedom vibration isolation platform to solve the problems in the background art.

[0005] The technical scheme of the present application is implemented as follows: a quasi-zero stiffness six-degree-of-freedom vibration isolation platform, comprising a base, three supporting legs and a top plate, the two ends of the supporting legs are connected with the top of the base and the bottom of the top plate through spherical hinges respectively, the spherical hinges on the base and the top plate are distributed in the same size equilateral triangle, the supporting legs are connected with the spherical hinges at the bottom of the top plate in turn and are inclined to the right, the supporting leg comprises an outer shell and a push rod, the push rod is vertically inserted into the outer shell through the top of the outer shell, a circular support plate is vertically sleeved on the lower part of the push rod and the inner side of the outer shell, an inner bellows is sleeved on the outer side of the push rod, an outer bellows is sleeved on the outer side of the inner bellows, the bottom of the inner bellows and the outer bellows is connected with the top of the support plate, the top of the inner bellows and the outer bellows is connected with the inner side of the top of the outer shell, an air cavity is formed between the inner bellows and the outer bellows, a hemispherical boss is arranged below the support plate and on the push rod, the outer side of the hemispherical boss is connected with an air spring through a roller, the other end of the air spring is vertically and fixedly installed on the inner side of the outer shell, the air spring comprises a cylinder, a piston A is installed in the cylinder, a guide rod is vertically installed on the top of the piston A and passes through the top of the cylinder, the top of the guide rod is connected with the roller, an additional air chamber is installed on the inner side of the bottom of the outer shell, a main air chamber is connected with the top of the additional air chamber through an air hole, a piston B is installed in the main air chamber, an electromagnetic coil is installed on the inner side of the bottom of the main air chamber, a permanent magnet is installed on the bottom of the piston B, the push rod is connected with the top of the piston B through the main air chamber, an air inlet pipe B which passes through the outer shell is installed on the additional air chamber, a pneumatic valve B is installed on the air inlet pipe B, a position sensor and an acceleration sensor are further installed on the bottom of the top plate, and a controller is further installed on the top of the base.

[0006] Further, the base and the top plate are both made of stainless steel plates into circular structures.

[0007] Further, the outer shell is a cylindrical structure with an internal cavity.

[0008] Further, the guide rod and the top of the cylinder are connected through a linear bearing A.

[0009] Further, the bottom of the cylinder is provided with an air inlet pipe A which passes through the outer shell, and a pneumatic valve A is installed on the air inlet pipe A.

[0010] Further, the air hole is arranged on both sides of the electromagnetic coil.

[0011] Further, a linear bearing B is installed between the push rod and the main air chamber, and a linear bearing C is installed between the push rod and the top of the outer shell.

[0012] Further, a sealing plate is further installed between the top of the air cavity and the outer shell, an air inlet pipe C which passes through the sealing plate and the top of the outer shell is installed on the top of the air cavity, and a pneumatic valve C is installed on the air inlet pipe C.

[0013] Further, the controller is connected with the position sensor, the acceleration sensor and the electromagnetic coil through a cable.

[0014] The present application has the following advantages:

[0015] The present application provides positive stiffness by connecting the main air chamber and the additional air chamber in series, the existence of the additional air chamber can expand the air floating structure volume, thereby reducing the system vertical natural frequency, and the adjustment of the positive stiffness and the carrying capacity of the system is realized by controlling the air pressure of the main air chamber and the additional air chamber, so as to meet the vibration isolation requirements of different precision instruments.

[0016] The present application provides positive stiffness by connecting the main air chamber and the additional air chamber in series, the existence of the additional air chamber can expand the air floating structure volume, thereby reducing the system vertical natural frequency, and the adjustment of the positive stiffness and the carrying capacity of the system is realized by controlling the air pressure of the main air chamber and the additional air chamber, so as to meet the vibration isolation requirements of different precision instruments.

[0017] The present application provides positive stiffness by connecting the main air chamber and the additional air chamber in series, the existence of the additional air chamber can expand the air floating structure volume, thereby reducing the system vertical natural frequency, and the adjustment of the positive stiffness and the carrying capacity of the system is realized by controlling the air pressure of the main air chamber and the additional air chamber, so as to meet the vibration isolation requirements of different precision instruments.

[0018] The present application can realize 0.1Hz~200Hz vibration control, vibration isolation bandwidth, six-degree-of-freedom vibration isolation, accurate positioning, can be applied to different types of precision instruments, the maximum load can reach 1000kg, the application range is wide, and the universality is strong. BRIEF DESCRIPTION OF DRAWINGS

[0019] Fig. 1 It is a structural schematic diagram of the present application.

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

[0021] In the figure, 1 is a base, 2 is a leg, 201 is an outer shell, 202 is a push rod, 203 is a support plate, 204 is an outer corrugated pipe, 205 is an inner corrugated pipe, 206 is an air cavity, 207 is a hemispherical bump, 208 is an air spring, 2081 is an air cylinder, 2082 is a piston A, 2083 is a guide rod, 2084 is a linear bearing A, 2085 is an air inlet pipe A, 2086 is a pneumatic valve A, 209 is a roller, 210 is an additional air chamber, 211 is a main air chamber, 212 is an air hole, 213 is a piston B, 214 is an electromagnetic coil, 215 is a permanent magnet, 216 is an air inlet pipe B, 217 is a pneumatic valve B, 218 is a linear bearing B, 219 is a linear bearing C, 220 is a sealing plate, 221 is an air inlet pipe C, 222 is a pneumatic valve C, 3 is a top plate, 4 is a spherical hinge, 5 is a position sensor, 6 is an acceleration sensor, and 7 is a controller. EMBODIMENT

[0022] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0023] like Figs. 1-2 As shown, a quasi-zero stiffness six-degree-of-freedom vibration isolation platform includes a base 1, legs 2, and a top plate 3. There are three legs 2, each connected at both ends to the top of the base 1 and the bottom of the top plate 3 via ball joints 4. The ball joints 4 on the base 1 and the top plate 3 are arranged in an equilateral triangle of the same size. The legs 2 are sequentially inclined to the right and connected to the ball joints 4 at the bottom of the top plate 3. Each leg 2 includes a housing 201 and a push rod 202. The push rod 202 vertically passes through the top of the housing 201 and inserts into the housing 201. The lower part of the push rod 202 and the inner side of the housing 201 are perpendicular to each other. A circular support plate 203 is mounted on the straight section. An inner corrugated tube 205 is mounted on the outer side of the push rod 202, and an outer corrugated tube 204 is mounted on the outer side of the inner corrugated tube 205. The bottoms of the inner corrugated tube 205 and the outer corrugated tube 204 are connected to the top of the support plate 203, and the tops of the inner corrugated tube 205 and the outer corrugated tube 204 are connected to the inner side of the top of the outer shell 201. An air cavity 206 is formed between the inner corrugated tube 205 and the outer corrugated tube 204. A hemispherical protrusion 207 is provided below the support plate 203 and on the push rod 202. The outer side is connected to the air spring 208 via roller 209. The other end of the air spring 208 is vertically fixed to the inner side of the housing 201. The air spring 208 includes a cylinder 2081. A piston A2082 is installed inside the cylinder 2081. A guide rod 2083 is vertically installed on the top of the piston A2082, passing through the top of the cylinder 2081. The top of the guide rod 2083 is connected to the roller 209. An auxiliary air chamber 210 is installed at the bottom of the inner side of the housing 201. The top of the auxiliary air chamber 210 is connected to the main air chamber 2 through an air hole 212. 11. A piston B213 is installed inside the main air chamber 211. An electromagnetic coil 214 is installed at the bottom of the inner side of the main air chamber 211. A permanent magnet 215 is installed at the bottom of the piston B213. The push rod 202 passes vertically through the main air chamber 211 and is connected to the top of the piston B213. An air inlet pipe B216 that passes through the outer shell 201 is installed in the auxiliary air chamber 210. A pneumatic valve B217 is installed on the air inlet pipe B216. A position sensor 5 and an acceleration sensor 6 are also installed at the bottom of the top plate 3. A controller 7 is also installed on the top of the base 1.

[0024] Both the base 1 and the top plate 3 are made of stainless steel plates in a circular structure.

[0025] The shell 201 is a cylindrical structure with an enclosed cavity.

[0026] The guide rod 2083 is connected to the top of the cylinder 2081 through a linear bearing A2084.

[0027] The bottom of the cylinder 2081 is provided with an air inlet pipe A2085 which penetrates the shell 201, and the air inlet pipe A2085 is provided with a pneumatic valve A2086.

[0028] The air holes 212 are arranged on both sides of the electromagnetic coil 214.

[0029] The push rod 202 is provided with a linear bearing B218 between the main air chamber 211 and the push rod 202, and a linear bearing C219 between the push rod 202 and the top of the shell 201.

[0030] The top of the air cavity 206 is further provided with a sealing plate 220 between the top of the air cavity 206 and the shell 201, and the top of the air cavity 206 is provided with an air inlet pipe C221 which penetrates the sealing plate 220 and the top of the shell 201, and the air inlet pipe C221 is provided with a pneumatic valve C222.

[0031] The controller 7 is connected to the position sensor 5, the acceleration sensor 6 and the electromagnetic coil 214 through a cable.

[0032] During installation, the precision instrument is installed on the top plate 3, and the weight of the precision instrument is mainly borne by the series mechanism of the main air chamber 211 and the additional air chamber 210 of the three supporting legs 2, the air inlet amount of the air inlet pipe B216 is controlled through the pneumatic valve B217 to adjust the bearing capacity and the positive stiffness of the main air chamber 211 and the additional air chamber 210, the air inlet amount of the air inlet pipe C221 is controlled through the pneumatic valve C222 to control the negative stiffness of the air cavity 206, when the static balance is reached, the system reaches the quasi-zero stiffness state, at this time the roller 209 is located at the middle position of the hemispherical protrusion 207, at this time the air spring 208 does not exert a force on the push rod 202 in the vertical direction, then the air inlet amount of the air inlet pipe A2085 is controlled through the pneumatic valve A2086 to adjust the air pressure of the cylinder 2081 to adjust the negative stiffness of the air spring 208, so as to expand the vibration isolation bandwidth of the quasi-zero stiffness of the system.

[0033] In operation, the precision instrument generates vibration, and the vibration signal is collected by the position sensor 5 and the acceleration sensor 6, and then transmitted to the controller 7. When the vertical high-frequency vibration source is provided, the leg 2 provides positive stiffness through the series mechanism of the main air chamber 211 and the additional air chamber 210, and forms a positive-negative stiffness system with the negative stiffness provided by the air chamber 206 to realize primary high-frequency vibration reduction. In addition, when the vertical high-frequency vibration source is provided, the push rod 202 moves vertically, breaking the original static balance, at which time the roller 209 deviates from the center position of the hemispherical block 207, so that the air spring 208 provides negative stiffness in the vertical direction to realize secondary high-frequency vibration reduction; when the vertical low-frequency vibration source is provided, low-frequency vibration reduction is mainly realized by controlling the magnetic field strength and direction of the electromagnetic coil 214 through the controller 13.

[0034] In addition, the three legs 2 of the vibration isolation platform of the present application can be independently driven, and can realize six degrees of freedom vibration isolation in the up-down, front-back, left-right, around the X-axis, around the Y-axis and around the Z-axis directions.

[0035] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A quasi-zero stiffness six-degree-of-freedom vibration isolation platform, comprising a base, legs, and a top plate, wherein the legs are three in number, characterized in that... The two ends of the support legs are connected to the top of the base and the bottom of the top plate via ball joints, respectively. The ball joints on the base and top plate are arranged in an equilateral triangle of the same size. The support legs are sequentially tilted to the right and connected to the ball joints at the bottom of the top plate. Each support leg includes a housing and a push rod. The push rod is inserted vertically into the housing through the top of the housing. A circular support plate is vertically fitted on the lower part of the push rod and the inner side of the housing. An inner bellows is fitted on the outer side of the push rod, and an outer bellows is fitted on the outer side of the inner bellows. The bottoms of the inner and outer bellows are connected to the top of the support plate, and the tops of the inner and outer bellows are connected to the inner side of the top of the housing. An air cavity is formed between the inner and outer bellows. A sealing plate is also installed between the top of the air cavity and the housing. An air inlet pipe C is installed on the top of the air cavity, passing through the sealing plate and the top of the housing. A pneumatic valve C is installed on the air inlet pipe C. A hemispherical protrusion is provided below the support plate and on the push rod. The outer side of the hemispherical protrusion is connected to the support plate by rollers. An air spring is connected, with its other end vertically fixed to the inner side of the housing. The air spring includes a cylinder, inside which a piston A is installed. A guide rod is vertically installed on the top of piston A, passing through the top of the cylinder. The guide rod is connected to the top of the cylinder via a linear bearing A. The top of the guide rod is connected to a roller. An air inlet pipe A is installed at the bottom of the cylinder, passing through the housing. A pneumatic valve A is installed on the air inlet pipe A. An auxiliary air chamber is installed at the bottom of the inner side of the housing. The top of the auxiliary air chamber is connected to a main air chamber via an air hole. A piston B is installed inside the main air chamber. An electromagnetic coil is installed at the bottom of the inner side of the main air chamber. A permanent magnet is installed at the bottom of piston B. A push rod vertically passes through the main air chamber and is connected to the top of piston B. An air inlet pipe B is installed in the auxiliary air chamber, passing through the housing. A pneumatic valve B is installed on the air inlet pipe B. A position sensor and an acceleration sensor are also installed at the bottom of the top plate. A controller is also installed at the top of the base.

2. The quasi-zero stiffness six-degree-of-freedom vibration isolation platform according to claim 1, characterized in that, The base and top plate are both made of stainless steel plates in a circular structure.

3. The quasi-zero stiffness six-degree-of-freedom vibration isolation platform according to claim 1, characterized in that, The outer shell has a cylindrical structure containing a cavity.

4. The quasi-zero stiffness six-degree-of-freedom vibration isolation platform according to claim 1, characterized in that, The air holes are located on both sides of the electromagnetic coil.

5. The quasi-zero stiffness six-degree-of-freedom vibration isolation platform according to claim 1, characterized in that, A linear bearing B is installed between the push rod and the main air chamber, and a linear bearing C is installed between the push rod and the top of the outer casing.

6. The quasi-zero stiffness six-degree-of-freedom vibration isolation platform according to claim 1, characterized in that, The controller is connected to a position sensor, an acceleration sensor, and an electromagnetic coil via cables.

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