Parallel mechanism with six-degree-of-freedom vibration isolation and accurate positioning functions

Abstract

The parallel mechanism comprises a top plate, a base and an upper supporting leg, a partition plate is installed between the top plate and the base, the upper supporting leg is installed between the top plate and the partition plate, and the top of the upper supporting leg is connected with the bottom of the top plate through a flexible spherical hinge. The number of the upper supporting legs is six, every two adjacent upper supporting legs are perpendicular to each other, six lower supporting legs are perpendicularly installed on the top of the base, and the lower supporting legs penetrate through the partition plate and are connected with the upper supporting legs in a one-to-one correspondence mode through hooke joints. The device can realize 0.1-500Hz vibration control, vibration isolation bandwidth and six-degree-of-freedom vibration isolation, has the function of accurate positioning of a parallel mechanism, enables the driving distance of the system to be large through the serial connection of the servo motor and the voice coil motor, and can also be applied to the technical field of equipment for optical testing, measurement, alignment, detection and the like.

Description

Technical Field

[0001] The invention relates to the technical field of parallel mechanisms, in particular to a parallel mechanism with six-degree-of-freedom vibration isolation and precise positioning functions. Background Art

[0002] At present, the semiconductor industry is developing rapidly. The precision requirements of semiconductor production equipment are getting higher and higher, and 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 make the equipment unable to work normally. Therefore, the isolation of micro-vibration is becoming more and more important.

[0003] Parallel mechanisms have been widely used in aviation, aerospace, submarine operations, underground mining, manufacturing and assembly industries due to their high rigidity, strong load-bearing capacity and non-accumulation of position errors. The legs of traditional parallel mechanisms are driven by hydraulic cylinders, which are bulky and have low precision, and have certain limitations. In order to improve its positioning accuracy, parallel mechanisms using linear motors and piezoelectric drives as drive devices have emerged. Although the positioning accuracy has been improved, its load-bearing capacity has been significantly reduced. Although there are also parallel mechanisms using servo motors as drive devices, the positioning accuracy is better than that of hydraulic cylinder drives, but it still cannot meet the requirements of precise positioning.

[0004] In addition, the traditional parallel mechanism has a certain vibration control capability, but its stiffness is fixed, the vibration isolation band is narrow, and the application object is single and fixed. It is difficult to meet the vibration isolation requirements of complex environments and cannot meet the vibration isolation requirements of different objects, and has poor versatility. Summary of the invention

[0005] The purpose of the present invention is to provide a parallel mechanism with six-degree-of-freedom vibration isolation and precise positioning functions to solve the problems existing in the above-mentioned background technology.

[0006] The technical solution of the present invention is achieved as follows: a parallel mechanism with six-degree-of-freedom vibration isolation and precise positioning functions, comprising a top plate, a base and an upper leg, a partition is installed between the top plate and the base, the upper leg is installed between the top plate and the partition, the top of the upper leg is connected to the bottom of the top plate through a flexible ball joint, there are six upper legs and two adjacent upper legs are perpendicular to each other, six lower legs are vertically installed on the top of the base, the lower legs pass through the partition and are connected to the upper legs one by one through Hooke's hinges, the lower legs comprise a shell A, a servo motor is installed in the middle of the bottom inner side of the shell A, a ball screw is connected to the top of the servo motor, a ball nut is mounted on the ball screw, a drive sleeve is connected to the ball nut, the ball screw is inserted into the drive sleeve, the upper leg comprises a shell B, a piston is installed on the inner side of the shell B, the The piston is connected to the inner wall of the shell B through an air film, and the piston, air film and shell B form an air chamber. A guide rod is vertically installed inside the piston, a support plate is installed on the inner side of the shell B, a support plate is installed on the guide rod, between the support plate and the top of the inner side of the shell B, metal springs A are respectively installed on both sides of the guide rod, between the support plate and the inner side of the top of the shell B, metal springs B are respectively installed on both sides of the guide rod, between the support plate and the support plate, electromagnets are respectively installed on both sides of the guide rod and at the bottom of the support plate, permanent magnets are respectively installed on both sides of the guide rod, at positions corresponding vertically to the electromagnets, a voice coil motor is installed in the middle of the bottom of the piston and the bottom of the inner side of the shell B, an intake pipe is opened on one side of the shell B to communicate with the air chamber, a servo valve is installed on the intake pipe, an acceleration sensor and a position sensor are also installed at the bottom of the top plate, and a controller is also installed on the top of the partition.

[0007] Furthermore, the top plate, the partition plate and the base are all made of stainless steel plates in a hexagonal structure.

[0008] Furthermore, the lower leg passes through the partition and is connected to the partition via a linear bearing A.

[0009] Furthermore, the driving sleeve passes through the shell A and is connected to the shell A through a linear bearing B. A cushion block is also vertically installed on the top of the driving sleeve, and the middle of the top of the cushion block is connected to the middle of the bottom of the shell B of the upper leg through a Hooke's hinge.

[0010] Furthermore, a support column is installed in the middle of the top of the base and in the middle of the bottom of the partition.

[0011] Furthermore, a baffle A is installed on the top of the ball screw to prevent the driving sleeve from slipping off the ball screw.

[0012] Furthermore, a baffle B is installed inside the shell A, a gap is left between the baffle B and the ball screw, and legs are installed between the bottom of the baffle B and the bottom of the shell A and on both sides of the servo motor.

[0013] Furthermore, the guide rod vertically passes through the support plate and the shell B and is connected to the bottom of the top plate through a flexible ball joint. The guide rod is connected to the shell B through a linear bearing C, and the guide rod is connected to the support plate through a linear bearing D.

[0014] Furthermore, the controller is connected to the acceleration sensor, the position sensor, the servo motor, the electromagnet, and the voice coil motor through cables.

[0015] The beneficial effects of the present invention are: The present invention adjusts the bearing capacity and positive stiffness of the system through the air chamber, and adjusts the negative stiffness of the system through magnetic control, so that the system reaches quasi-zero stiffness when in static balance, and has the characteristics of high static and low dynamic stiffness.

[0016] The present invention realizes secondary vibration reduction of high-frequency vibration by using two sets of metal springs connected in parallel, and further compensates for vibration reduction by a servo motor connected in series, thereby realizing vibration reduction of higher vibration sources and realizing vibration reduction of low-frequency vibration sources by using a voice coil motor.

[0017] The device of the present invention can achieve vibration control of 0.1Hz~500Hz, a wide vibration isolation bandwidth, can achieve six-degree-of-freedom vibration isolation, and has precise positioning. It can meet the vibration isolation requirements of precision instruments of different models, has a maximum load-bearing capacity of 3000kg, has a wide range of applications, and is highly versatile.

[0018] The device of the present invention also has the function of precise positioning of the parallel mechanism. The system driving distance is large through the series connection of the servo motor and the voice coil motor. It can also be applied to the technical fields of optical testing, measurement, alignment, detection and other equipment. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0021] Figure 3 It is a schematic structural diagram of the upper supporting leg of the present invention.

[0022] In the figure, 1-top plate, 2-base, 3-partition plate, 301-linear bearing A, 4-lower leg, 401-housing A, 402-servo motor, 403-ball screw, 404-ball nut, 405-drive sleeve, 406-linear bearing B, 407-baffle A, 408-baffle B, 409-leg, 5-upper leg, 501-housing B, 502-air chamber, 503-piston, 504-air film, 505 -guide rod, 506-support plate, 507-support plate, 508-metal spring A, 509-metal spring B, 510-electromagnet, 511-permanent magnet, 512-voice coil motor, 513-linear bearing C, 514-linear bearing D, 515-intake pipe, 516-servo valve, 6-pillar, 7-flexible ball joint, 8-Hook's joint, 9-acceleration sensor, 10-position sensor, 11-controller, 12-pad. DETAILED DESCRIPTION

[0023] The technical solution of the present invention will be described clearly and completely in conjunction with the embodiments below. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] like Figure 1-3As shown, a parallel mechanism with six-degree-of-freedom vibration isolation and precise positioning functions includes a top plate 1, a base 2 and an upper leg 5, a partition 3 is installed between the top plate 1 and the base 2, the upper leg 5 is installed between the top plate 1 and the partition 3, the top of the upper leg 5 is connected to the bottom of the top plate 1 through a flexible ball joint 7, there are six upper legs 5 and two adjacent upper legs 5 are perpendicular to each other, six lower legs 4 are vertically installed on the top of the base 2, the lower legs 4 pass through the partition 3 and are connected to the upper legs 5 through a Hooke's hinge 8 in a one-to-one correspondence, and the lower legs 4 include The housing A401 has a servo motor 402 installed in the middle of the bottom inner side of the housing A401, a ball screw 403 is connected to the top of the servo motor 402, a ball nut 404 is mounted on the ball screw 403, a drive sleeve 405 is connected to the ball nut 404, the ball screw 403 is inserted into the drive sleeve 405, and the upper leg 5 includes a housing B501, a piston 503 is installed on the inner side of the housing B501, and the piston 503 is connected to the inner wall of the housing B501 through an air film 504. The membrane 504 and the shell B501 form an air chamber 502, a guide rod 505 is vertically installed inside the piston 503, a support plate 506 is installed inside the shell B501, a support plate 507 is installed on the guide rod 505 and between the support plate 506 and the top of the inner side of the shell B501, metal springs A508 are installed on both sides of the guide rod 505 and between the support plate 507 and the inner side of the top of the shell B501, metal springs B509 are installed on both sides of the guide rod 505 and between the support plate 507 and the support plate 506, and the guide rod 505 is installed on both sides. Electromagnets 510 are installed on the side and the bottom of the support plate 506, respectively. Permanent magnets 511 are installed on both sides of the guide rod 505 and on the top of the piston 503 at positions vertically corresponding to the electromagnet 510. A voice coil motor 512 is installed in the middle of the bottom of the piston 503 and the bottom of the shell B501. An air intake pipe 515 is opened on one side of the shell 501B to communicate with the air chamber 502, and a servo valve 516 is installed on the air intake pipe. An acceleration sensor 9 and a position sensor 10 are also installed at the bottom of the top plate 1, and a controller 11 is also installed on the top of the partition 3.

[0025] The top plate 1, the partition plate 3 and the base 2 are all made of stainless steel plates into a hexagonal structure.

[0026] The lower leg 4 passes through the partition 3 and is connected to the partition 3 via a linear bearing A301.

[0027] The driving sleeve 405 passes through the shell A401 and is connected to the shell A401 through a linear bearing B406. A cushion block 12 is also vertically installed on the top of the driving sleeve 405. The middle of the top of the cushion block 12 is connected to the middle of the bottom of the shell B501 of the upper leg 5 through a Hooke's hinge 8.

[0028] A support column 6 is also installed in the middle of the top of the base 2 and the middle of the bottom of the partition 3.

[0029] A baffle A407 is also installed on the top of the ball screw 403 to prevent the driving sleeve 405 from slipping off the ball screw 403.

[0030] A baffle B408 is installed inside the housing A401 , a gap is left between the baffle B408 and the ball screw 403 , and legs 409 are installed between the bottom of the baffle B408 and the bottom of the housing A401 and on both sides of the servo motor 402 .

[0031] The guide rod 505 vertically passes through the support plate 506 and the shell B501 and is connected to the bottom of the top plate 1 through a flexible ball joint 7. The guide rod 505 and the shell B501 are connected through a linear bearing C513, and the guide rod 505 and the support plate 506 are connected through a linear bearing D514.

[0032] The controller 11 is connected to the acceleration sensor 9 , the position sensor 10 , the servo motor 402 , the electromagnet 510 , and the voice coil motor 512 via cables.

[0033] During installation, the precision instrument is installed on the top plate 1. The intake volume of the intake pipe 515 is adjusted by the servo valve 516 to adjust the air pressure of the air chamber 502 to adjust the bearing capacity and positive stiffness of the system. The magnetic field strength of the electromagnet 510 is controlled by the controller 11 to adjust the repulsive force between the electromagnet 510 and the permanent magnet 511, thereby adjusting the negative stiffness of the system. When static equilibrium is reached, the system reaches a quasi-zero stiffness state, and the metal spring A508 and the metal spring B509 are in a natural expansion and contraction state.

[0034] When working, the precision instrument generates vibration, and the signal is collected through the acceleration sensor 9 and the position sensor 10, and then the vibration signal is transmitted to the controller 11. When the vibration source is high frequency, the metal spring A508 and the metal spring B509 form a parallel mechanism to achieve secondary high frequency vibration reduction. At the same time, the controller 11 controls the servo motor 402 of the series lower leg 4 to control the drive sleeve 405 to drive and compensate for the high frequency vibration reduction, which can achieve vibration reduction for higher vibration sources; when the vibration source is low frequency, the voice coil motor 512 is driven by the controller 11 to achieve low frequency vibration reduction.

[0035] The six lower legs 5 and the six upper legs 5 of the vibration isolation device of the present invention can be driven independently, respectively, so as to realize six free vibration isolations along the X axis, along the Y axis, along the Z axis, 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 principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A parallel mechanism with six-degree-of-freedom vibration isolation and precise positioning functions, comprising a top plate, a base and an upper leg, characterized in that: A partition is installed between the top plate and the base, the upper leg is installed between the top plate and the partition, the top of the upper leg is connected to the bottom of the top plate through a flexible ball joint, there are six upper legs and two adjacent upper legs are perpendicular to each other, six lower legs are vertically installed on the top of the base, the lower legs pass through the partition and are connected to the upper legs one by one through Hook's hinges, the lower legs include a shell A, a servo motor is installed in the middle of the bottom inner side of the shell A, a ball screw is connected to the top of the servo motor, a ball nut is mounted on the ball screw, a drive sleeve is connected to the ball nut, the ball screw is inserted into the drive sleeve, the upper leg includes a shell B, a piston is installed on the inner side of the shell B, the piston is connected to the inner wall of the shell B through an air film, the piston, the air film and the shell B forms an air chamber, a guide rod is vertically installed inside the piston, a support plate is installed on the inner side of the shell B, a support plate is installed on the guide rod and between the support plate and the inner top of the shell B, metal springs A are respectively installed on both sides of the guide rod and between the support plate and the inner side of the top of the shell B, metal springs B are respectively installed on both sides of the guide rod and between the support plate and the support plate, electromagnets are respectively installed on both sides of the guide rod and at the bottom of the support plate, permanent magnets are respectively installed on both sides of the guide rod and at positions vertically corresponding to the electromagnets on the top of the piston, a voice coil motor is installed in the middle of the bottom of the piston and the bottom of the shell B, an intake pipe is opened on one side of the shell B to communicate with the air chamber, a servo valve is installed on the intake pipe, an acceleration sensor and a position sensor are also installed at the bottom of the top plate, and a controller is also installed on the top of the partition.

2. A parallel mechanism with six-degree-of-freedom vibration isolation and precise positioning functions according to claim 1, characterized in that: The top plate, the partition plate and the base are all made of stainless steel plates into a hexagonal structure.

3. The parallel mechanism with six-degree-of-freedom vibration isolation and precise positioning function according to claim 1, characterized in that: The lower leg passes through the partition and is connected to the partition through a linear bearing A.

4. The parallel mechanism with six-degree-of-freedom vibration isolation and precise positioning functions according to claim 1, characterized in that: The driving sleeve passes through the shell A and is connected to the shell A through a linear bearing B. A cushion block is also vertically installed on the top of the driving sleeve. The middle of the top of the cushion block is connected to the middle of the bottom of the shell B of the upper leg through a Hooke hinge.

5. The parallel mechanism with six-degree-of-freedom vibration isolation and precise positioning function according to claim 1, characterized in that: A support column is also installed in the middle of the top of the base and the middle of the bottom of the partition.

6. The parallel mechanism with six-degree-of-freedom vibration isolation and precise positioning functions according to claim 1, characterized in that: A baffle A is also installed on the top of the ball screw to prevent the driving sleeve from slipping off the ball screw.

7. The parallel mechanism with six-degree-of-freedom vibration isolation and precise positioning functions according to claim 1, characterized in that: A baffle B is installed inside the housing A, a gap is left between the baffle B and the ball screw, and legs are installed between the bottom of the baffle B and the bottom of the housing A and on both sides of the servo motor.

8. The parallel mechanism with six-degree-of-freedom vibration isolation and precise positioning functions according to claim 1, characterized in that: The guide rod vertically passes through the support plate and the shell B and is connected to the bottom of the top plate through a flexible ball joint. The guide rod is connected to the shell B through a linear bearing C, and the guide rod is connected to the support plate through a linear bearing D.

9. The parallel mechanism with six-degree-of-freedom vibration isolation and precise positioning functions according to claim 1, characterized in that: The controller is connected with the acceleration sensor, the position sensor, the servo motor, the electromagnet and the voice coil motor through cables.

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