CN103047343B - Electromagnetic damping zero-stiffness vibration isolator with angular decoupling function by aid of sliding joint bearing - Google Patents

Abstract

The electromagnetic damping zero-stiffness vibration isolator with angular decoupling of the sliding joint bearing belongs to the field of precision vibration isolation technology. The sleeve of the main body of the vibration isolator and the lower mounting plate, the piston cylinder and the sleeve are lubricated and supported by the air bearing surface respectively. The electromagnetic damper attenuates vibration energy and improves positioning stability. The degree of freedom of angular motion between the upper mounting plate and the lower mounting plate is decoupled through sliding joint bearings. The voice coil motor, displacement sensor, limit switch, controller, and driver are composed The position closed-loop feedback control system accurately controls the relative position of the upper and lower mounting plates; the invention has zero stiffness in the vertical and horizontal directions, high positioning accuracy and angle decoupling characteristics, and can obtain extremely low natural frequency and prominent low frequency /Ultra-low frequency vibration isolation performance, so as to effectively solve the problem of high-performance vibration isolation in ultra-precision measuring instruments and processing equipment, especially in step-scan lithography machines.

Description

Electromagnetic Damping Zero Stiffness Vibration Isolator with Angular Decoupling of Sliding Joint Bearings

technical field

The invention belongs to the technical field of precision vibration isolation, and mainly relates to an electromagnetic damping zero-stiffness vibration isolator with angular decoupling of sliding joint bearings.

Background technique

With the continuous improvement of ultra-precision machining and measurement accuracy, environmental vibration has become an important factor restricting the improvement of the accuracy and performance of ultra-precision machining equipment and measuring instruments. In particular, the ultra-large-scale integrated circuit processing equipment represented by the step-scan lithography machine is extremely technically intensive and complex, and the key technical indicators have reached the limit of the existing technology, representing the highest level of ultra-precision processing equipment. Precision vibration isolation has become the core key technology in this type of equipment; the line width of the step-and-scan lithography machine has reached 22nm and below, the positioning accuracy and overlay accuracy of silicon wafers have reached several nanometers, and the movement speed of the workpiece table has reached 1m/s Above, the acceleration of the workpiece table reaches dozens of times of the acceleration of gravity, which poses a new challenge to the existing vibration isolation technology. First of all, the lithography machine needs to provide an "ultra-quiet" working environment for the metrology system and the lithography objective lens, and at the same time needs to drive the workpiece table to move at high speed and high acceleration, which poses extremely strict requirements on the vibration isolation performance of the vibration isolation system. It is required that the natural frequencies in the three directions must be below 1Hz; secondly, the relative position between the various components of the lithography machine, such as the distance between the lithography objective lens and the surface of the silicon wafer, has very strict requirements and is in a position closed loop Under the control of the feedback control system, the relative position accuracy between the upper and lower mounting plates of the vibration isolator is required to reach the order of 10 μm, and the positioning accuracy of the traditional vibration isolator is far from meeting the requirements.

According to the vibration isolation theory, the natural frequency of a passive vibration isolator is proportional to the stiffness and inversely proportional to the load mass. Therefore, under the premise of a certain load mass, reducing the stiffness of the vibration isolator is to reduce the natural frequency and improve low frequency and ultra-low frequency vibration isolation. efficient way to perform. Vibration isolators in the form of traditional air springs have an inherent contradiction between static load capacity and stiffness. At the same time, they are constrained by factors such as material properties and structural stiffness. It is very difficult to further reduce their stiffness, especially the horizontal stiffness. In response to this problem, the researchers introduced the "pendulum" structure into the air spring vibration isolator to achieve the purpose of reducing the horizontal stiffness of the vibration isolator (1. Nikon Corporation. Vibration Isolator With Low Lateral Stiffness. US Patent Publication No.: US20040065517A1 ; 2. U.S.Philips Corporation. Positioning Device with a Force Actuator System for Compensating Center-of-gravity Displacements, and Lithographic Device Provided with Such APositioning Device. U.S. Patent No.: US005844664A). This method can reduce the horizontal stiffness of the air spring isolator to a certain extent and improve its low-frequency vibration isolation performance. The problems of this method are as follows: 1) Due to the constraints of material properties and structural stiffness, the amplitude of vertical and horizontal stiffness reduction of the vibration isolator is limited; 2) The vertical and horizontal positioning accuracy of the air spring vibration isolator is very poor, It cannot meet the requirements of the photolithography process; 3) To achieve a lower horizontal stiffness requires a larger pendulum length, resulting in excessive height of the vibration isolator, prone to string-membrane resonance, and poor stability.

Through the analysis of the technical scheme of the existing air spring isolator, it can be seen that the existing air spring isolator is difficult to meet the requirements of ultra-low stiffness and high positioning accuracy of the lithography machine. The German IDE company proposed a vibration isolator technology solution that abandons the traditional rubber air spring (1. Integrated Dynamics Engineering GmbH. Isolatorgeometrie Eines Schwingungsisolationssystem. European Patent No.: EP1803965A2; 2. Integrated Dynamics Engineering GmbH. Schwingungsisolationssystem Mit Pneumatischemil. European Patent No.: filter Tiefpass EP1803970A2; 3. Integrated Dynamics Engineering GmbH. Air Bearing with Consideration of High-Frequency Resonances. US Patent Publication No.: US20080193061A1). The solution uses vertical and horizontal air bearings to decouple and isolate vibrations in all directions, which can achieve extremely low stiffness and natural frequency. The problems of this solution are: 1) In the disclosed technical solution, the vibration isolator cannot achieve precise positioning; 2) In the patent EP1803965A2, there is no degree of freedom of angular movement around the horizontal axis between the upper and lower mounting plates. The angular stiffness and natural frequency are very high; patents EP1803970A2 and US20080193061A1 use rubber blocks to provide angular freedom of rotation around the horizontal axis for the upper and lower mounting plates, but due to the high angular stiffness of the rubber blocks, the angular freedom of motion cannot be effectively achieved Degree of freedom decoupling, the friction between the components of the angular motion degree of freedom decoupling mechanism introduces additional stiffness, which restricts the vibration isolation performance.

Netherlands ASML company also proposed a similar vibration isolator technical scheme (1. U.S.Philips Corp, ASM Lithography B.V. Pneumatic Support Device with A Controlled Gas Supply, and Lithographic Device Provided with Such A Support Device. U.S. Patent No.: US006144442A; 2 .Koninklijke Philips ElectronicsN.V.，ASM Lithography B.V.Lithographic Pneumatic Support Device with Controlled Gas Supply.国际专利公开号：WO99/22272；3.ASML Netherlands B.V.Support Device，LithographicApparatus，and Device Manufacturing Method Employing A Supporting Device，and A PositionControl System Arranged for Use in A Supporting Device.美国专利号：US007084956B2；4.ASML Netherlands B.V.Support Device，Lithographic Apparatus，and Device ManufacturingMethod Employing A Supporting Device and A Position Control System Arranged for Use in ASupporting Device.欧洲专利号： EP1486825A1). In patent US006144442A and WO99/22272, closed-loop feedback control is performed on the air source pressure to achieve the purpose of improving the stability and performance of the vibration isolator; in patent US007084956B2 and EP1486825A1, a vibration sensor is installed on the upper mounting plate, and a reference vibration system is introduced at the same time. The vibration isolation performance of the vibration isolator is improved through the control algorithm. However, the proposed technical solution still does not solve the problem of decoupling the precise positioning of the vibration isolator and the angular motion degrees of freedom of the upper and lower mounting plates.

Contents of the invention

The purpose of the present invention is to provide a sliding joint bearing for the urgent requirements of ultra-precision measuring instruments and processing equipment, especially ultra-large-scale integrated circuit processing equipment such as step-scan lithography machines, for vibration isolators with low natural frequency and high positioning accuracy. Angle-decoupled electromagnetic damping zero-stiffness vibration isolator. The vibration isolator has the characteristics of three-dimensional approximate zero stiffness and extremely low natural frequency. The upper and lower mounting plates can be accurately positioned and angle-decoupled, thus effectively solving ultra-precision measurement. Precision vibration isolation in instruments and processing equipment, especially in step-and-scan lithography machines.

Technical solution of the present invention is:

An electromagnetic damping zero-stiffness vibration isolator with angular decoupling of sliding joint bearings, consisting of an upper mounting plate, a lower mounting plate, a clean compressed air source, a gas pipe, and a main body of the vibration isolator. The main body of the vibration isolator is installed on the upper mounting plate and the lower mounting plate. Between the mounting plates), the clean compressed air source is connected to the main body of the vibration isolator through the air pipe. In the main body of the vibration isolator, the lower surface of the sleeve and the lower mounting plate are lubricated and supported by the axial bearing plane air bearing surface, and the piston barrel is inverted The buckle is installed in the sleeve, and the sleeve is lubricated and supported by the radial bearing cylinder air bearing surface, the sliding joint bearing is installed between the piston cylinder and the upper mounting plate, the Z-direction voice coil motor, the Z-direction displacement sensor, the Z-direction limiter The position switch is installed between the piston barrel and the sleeve, and the X-direction voice coil motor, X-direction displacement sensor, X-direction limit switch and Y-direction voice coil motor, Y-direction displacement sensor, and Y-direction limit switch are installed between the sleeve and the Between the lower mounting plates; the driving force direction of the Z-direction voice coil motor is the vertical direction, the driving force directions of the X-direction voice coil motor and Y-direction voice coil motor are in the horizontal plane and perpendicular to each other, and the X, Y, and Z direction displacement sensors The action line direction of the X, Y, Z direction limit switch is consistent with the driving force direction of the X, Y, Z direction voice coil motor; the X, Y, Z direction displacement sensor and the X, Y, Z direction limit switch are respectively connected with The signal input terminal of the controller is connected, the signal output terminal of the controller is connected with the signal input terminal of the driver, and the signal output terminal of the driver is respectively connected with the voice coil motor in X, Y and Z directions; An X-direction permanent magnet is installed in the driving force direction of the voice coil motor to form an X-direction electromagnetic damper, and a Y-direction permanent magnet is installed on the side wall of the upper surface of the lower mounting plate along the Y-direction voice coil motor driving force to form a Y-direction electromagnetic damper. Z-direction permanent magnets are installed along the Z-direction voice coil motor driving force direction on the side wall of the cylindrical surface to form a Z-direction electromagnetic damper. The magnetic pole directions of the X and Y permanent magnets are perpendicular to the upper surface of the lower mounting plate, and the N and S poles are arranged alternately. , The magnetic pole direction of the Z-direction permanent magnet is perpendicular to the outer cylindrical surface of the piston cylinder, and the N and S poles are arranged alternately. The piston cylinder and the lower mounting plate are made of ferromagnetic materials, and the sleeve is made of non-magnetic good conductor material.

A gas pressure sensor is arranged in the piston barrel, an air inlet and a solenoid valve are arranged on the piston barrel, the gas pressure sensor is connected to the signal input end of the controller, the signal output end of the controller is connected to the signal input end of the driver, and the driver The signal output terminal is connected with the solenoid valve.

The voice coil motors in the X, Y and Z directions are cylindrical voice coil motors or flat voice coil motors.

The X, Y, and Z direction displacement sensors are grating scales, magnetic scales, capacitive scales or linear potentiometers.

The X-, Y-, and Z-direction limit switches are mechanical limit switches, Hall-type limit switches or photoelectric limit switches.

The gas pressure in the piston barrel is 0.1MPa-0.8MPa.

The air film thickness of the axial bearing plane air bearing surface and the radial bearing cylindrical air bearing surface is 10 μm to 20 μm.

The diameter of the orifice on the cylindrical air-floating surface on the piston barrel and the orifice on the plane air-floating surface on the sleeve is φ0.1mm˜φ1mm.

The technical innovation of the present invention and the good effect that produce are:

(1) The present invention abandons the traditional vibration isolator technical scheme based on elastic elements/mechanisms, and adopts the axial bearing flat air bearing surface and the radial bearing cylindrical air bearing surface to decouple and isolate the horizontal and vertical vibrations respectively. The floating surface has no friction and the stiffness is approximately zero, which enables the vibration isolator to obtain approximately zero stiffness characteristics and outstanding ultra-low frequency vibration isolation performance, which solves the problem that the existing technology is limited by structural stiffness and material properties, and the stiffness is difficult to further reduce. Stiffness and stability Sexual incompatibility. This is one of the innovative points that the present invention is different from the prior art.

(2) The present invention adopts displacement sensor ruler, limit switch, controller, driver and voice coil motor etc. to constitute the position closed-loop feedback control system of vertical direction and horizontal direction, and the relative position between upper and lower mounting plate is accurately carried out. control, the positioning accuracy can reach 10 μm and above, which can effectively solve the problems of low positioning accuracy of existing technical solutions, and the inability to balance positioning accuracy with stiffness and vibration isolation performance. This is the second innovative point that the present invention is different from the prior art.

(3) The present invention uses a sliding joint bearing to decouple the angular motion between the upper and lower mounting plates. The sliding joint bearing introduces less friction, wear and additional angular stiffness, and at the same time has a high load-carrying capacity, which can effectively solve the problem of The existing method of angular decoupling using elastic body introduces a large additional angular stiffness, restricts the natural frequency and low frequency vibration isolation performance and other problems. This is the third innovative point that the present invention is different from the prior art.

(4) The present invention adopts a gas pressure sensor, a solenoid valve, a controller, a driver, etc. to form a pressure closed-loop feedback control system to precisely control the gas pressure in the sleeve to keep it constant, and to balance the gravity and balance the axial load of the vibration isolator. Compensation, under the action of the air bearing surface of the radial bearing cylinder, the piston cylinder carrying the load gravity can slide up and down freely along the sleeve with zero stiffness, so as to achieve the ideal gravity balance and zero stiffness vibration isolation effect. This is the fourth innovative point that the present invention is different from the prior art.

(5) The present invention uses an active actuator to actively control the relative position between the upper and lower mounting plates, and the parameters of the vibration isolator can be adjusted in real time according to the characteristics of the vibration-isolated object and the change of the working environment, so as to adapt to different working conditions. It has good flexibility, adaptability and stability. This is the fifth innovative point that the present invention is different from the prior art.

(6) The present invention adopts an electromagnetic damper based on an alternating magnetic pole permanent magnet array, which can be well integrated with a vibration isolator. The electromagnetic damper has a relatively ideal linear damping characteristic, which can effectively attenuate vibration energy and reduce motor drive. The positioning overshoot provides the stability of the isolator. This is the sixth innovation point that the present invention is different from the prior art.

Description of drawings

Fig. 1 is a schematic structural diagram of an electromagnetic damping zero-stiffness vibration isolator with angular decoupling of a sliding joint bearing;

Figure 2 is a schematic diagram of a three-dimensional cross-sectional structure of an electromagnetic damping zero-stiffness vibration isolator with angular decoupling of a sliding joint bearing;

Fig. 3 is a structural schematic diagram of a sliding joint bearing;

Fig. 4 is a block diagram of the control structure of the electromagnetic damping zero-stiffness vibration isolator with angular decoupling of the sliding joint bearing;

Fig. 5 is the schematic diagram of the orifice on the plane air bearing surface on the sleeve;

Fig. 6 is the schematic diagram of the orifice on the cylindrical air bearing surface on the piston barrel;

Fig. 7 is a schematic cross-sectional structure diagram of a Z-direction electromagnetic damper;

Fig. 8 is a schematic diagram of a partial cross-sectional structure of an electromagnetic damper in the X and Y directions;

Fig. 9 is an A-A sectional view of an installation method of the Z-direction permanent magnet on the side wall of the outer cylindrical surface of the piston barrel;

Fig. 10 is an A-A sectional view of another installation method of the Z-direction permanent magnet on the outer cylindrical side wall of the piston barrel;

Fig. 11 is a schematic diagram of an installation method of the X and Y direction permanent magnets on the upper side wall of the lower mounting plate;

Fig. 12 is a schematic diagram of another installation method of the X and Y direction permanent magnets on the upper side wall of the lower mounting plate.

Part number description in the figure: 1 upper mounting plate, 2 lower mounting plate, 3 clean compressed air source, 4 vibration isolator main body, 5 piston cylinder, 6 sleeve, 7 sliding joint bearing, 7a bearing body, 7b bearing seat, 8 X-direction voice coil motor, 9 Y-direction voice coil motor, 9a Y-direction motor iron yoke, 9b Y-direction motor magnet, 9c Y-direction motor coil bobbin, 9d Y-direction motor coil, 9e Y-direction motor transition piece, 10 Z-direction Voice coil motor, 10a Z-direction motor iron yoke, 10b Z-direction motor magnet, 10c Z-direction motor coil skeleton, 10d Z-direction motor coil, 10e Z-direction motor transition piece, 11 X-direction displacement sensor, 12 Y-direction displacement sensor, 12a Y-direction grating reading head transition piece, 12b Y-direction grating reading head, 12c Y-direction glass scale, 13 Z-direction displacement sensor, 13a Z-direction grating reading head transition piece, 13b Z-direction grating reading head, 13c Z-direction glass grating Ruler, 14 X-direction limit switch, 15 Y-direction limit switch, 15a Y-direction limit block, 15b Y-direction Hall switch, 15c Y-direction limit switch transition piece, 15d Y-direction limit block transition piece, 16 Z Direction limit switch, 16a Z direction limit block, 16b Z direction Hall switch, 16c Z direction limit switch transition piece, 17 Gas pressure sensor, 18 Solenoid valve, 19 Controller, 20 Driver, 21 Axial bearing plane gas Floating surface, 22 radial bearing cylindrical air bearing surface, 23 air inlet, 24 flat air bearing surface throttle hole, 25 cylindrical air bearing surface throttle hole, 26 air pipe, 40X direction electromagnetic damper, 40AX direction permanent magnet, 41 Y direction electromagnetic damping Device, 41A Y-direction permanent magnet, 42 Z-direction electromagnetic damper, 42A Z-direction permanent magnet.

Detailed ways

Specific embodiments of the present invention are given below in conjunction with the accompanying drawings.

An electromagnetic damping zero-stiffness vibration isolator with angular decoupling of sliding joint bearings, consisting of an upper mounting plate 1, a lower mounting plate 2, a clean compressed air source 3, an air pipe 26, and a vibration isolator body 4, the vibration isolator body 4 is installed Between the upper mounting plate 1 and the lower mounting plate 2, the clean compressed air source 3 is connected to the vibration isolator main body 4 through the air pipe 26. In the structure of the vibration isolator main body 4, the lower surface of the sleeve 6 is connected to the lower mounting plate 2 Lubricated and supported by the axial bearing plane air bearing surface 21, the piston barrel 5 is installed undercut in the sleeve 6, and is lubricated and supported with the sleeve 6 through the radial bearing cylindrical air bearing surface 22, and the sliding joint bearing 7 is installed in the piston barrel 5 and the upper mounting plate 1, the Z direction voice coil motor 10, the Z direction displacement sensor 13, and the Z direction limit switch 16 are installed between the piston barrel 5 and the sleeve 6, and the X direction voice coil motor 8 and the X direction displacement The sensor 11, the X-direction limit switch 14, the Y-direction voice coil motor 9, the Y-direction displacement sensor 12, and the Y-direction limit switch 15 are installed between the sleeve 6 and the lower mounting plate 2; the driving of the Z-direction voice coil motor 10 The force direction is the vertical direction, the driving force directions of the X-direction voice coil motor 8 and the Y-direction voice coil motor 9 are in the horizontal plane and are perpendicular to each other, and the X, Y and Z direction displacement sensors 11, 12, 13 and X, Y, Z The direction of the line of action to the limit switches 14, 15, 16 is consistent with the direction of the driving force of the X, Y, and Z direction voice coil motors 8, 9, 10; the X, Y, and Z direction displacement sensors 11, 12, 13 and X, Y, Z limit switch 14,15,16 is connected with the signal input end of controller 19 respectively, and the signal output end of controller 19 is connected with the signal input end of driver 20, and the signal output end of driver 20 is connected with X, Y respectively. , Z-direction voice coil motors 8, 9, 10 are connected; the X-direction permanent magnet 40A is installed on the upper surface side wall of the lower mounting plate 2 along the X-direction voice coil motor 8 driving force direction to form the X-direction electromagnetic damper 40, and on the lower mounting plate 2 A Y-direction permanent magnet 41A is installed on the side wall of the surface along the direction of the driving force of the Y-direction voice coil motor 9 to form a Y-direction electromagnetic damper 41. The magnet 42A constitutes the Z-direction electromagnetic damper 42, the magnetic pole directions of the X and Y permanent magnets 40A and 41A are perpendicular to the upper surface of the lower mounting plate 2, and the N and S poles are arranged alternately, and the magnetic pole directions of the Z-direction permanent magnet 42A are perpendicular to the upper surface of the lower mounting plate 2. The outer cylindrical surface of the piston barrel 5 is arranged alternately with N and S poles, the piston barrel 5 and the lower mounting plate 2 are made of ferromagnetic material, and the sleeve 6 is made of non-magnetic and good conductor material.

X, Y, and Z direction displacement sensors 11, 12, and 13 measure the displacement output by X, Y, and Z direction voice coil motors 8, 9, and 10, and X, Y, and Z direction limit switches 14, 15, and 16 are for X , Y, and Z direction voice coil motors 8,9,10 movement stroke limit; 16 feedback signals to control the X, Y, Z direction voice coil motors 8, 9, 10 to accurately control the relative position between the upper and lower mounting plates 1, 2.

Gas pressure sensor 17 is provided in described piston barrel 5, and air inlet 23 and solenoid valve 18 are provided on piston barrel 5, and gas pressure sensor 17 is connected with the signal input end of controller 19, and the signal output end of controller 19 is connected with The signal input end of the driver 20 is connected, and the signal output end of the driver 20 is connected with the solenoid valve 18 .

The voice coil motors 8, 9 and 10 in the X, Y and Z directions are cylindrical voice coil motors or flat voice coil motors.

The X, Y, Z direction displacement sensors 11, 12, 13 are grating scales, magnetic scales, capacitive scales or linear potentiometers.

The X, Y, and Z limit switches 14, 15, and 16 are mechanical limit switches, Hall-type limit switches or photoelectric limit switches.

The gas pressure in the piston barrel 5 is 0.1MPa-0.8MPa.

The air film thicknesses of the axial bearing plane air bearing surface 21 and the radial bearing cylindrical air bearing surface 22 are 10 μm˜20 μm.

The diameters of the cylindrical air bearing surface throttle hole 25 on the piston barrel 5 and the plane air bearing surface throttle hole 24 on the sleeve 6 are φ0.1mm˜φ1mm.

An embodiment of the present invention is given below in conjunction with FIG. 1 to FIG. 2 and FIG. 4 . In this embodiment, when the zero-stiffness vibration isolator works, the lower mounting plate 2 is installed on the foundation, the base of the instrument or the foundation frame, and the upper mounting plate 1 is connected to the load to be isolated. Voice coil motors 8, 9, and 10 in X, Y, and Z directions all adopt cylindrical voice coil motors. Taking Y-direction voice coil motor 9 as an example, it mainly includes Y-direction motor iron yoke 9a, Y-direction motor magnet 9b, Y-direction motor coil frame 9c, Y-direction motor coil 9d, Y-direction motor transition piece 9e and other components. Y-direction motor iron yoke 9a and Y-direction motor coil frame 9c are cylindrical, Y-direction motor magnetic steel 9b is cylindrical, Y-direction motor coil 9d is wound on Y-direction motor coil frame 9c, and Y-direction motor transition piece 9e provides The installation structure of the Y-direction motor bobbin 9c. The Y-direction motor iron yoke 9a and the Y-direction motor magnet steel 9b form the motor stator, and the Y-direction motor coil skeleton 9c and the Y-direction motor coil 9d form the mover of the motor. When the motor is working, a current is passed through the coil. According to the electromagnetic theory, the energized coil will be affected by the Lorentz force in the magnetic field. By controlling the magnitude and direction of the current, the magnitude and direction of the motor output driving force can be controlled.

X, Y, and Z direction displacement sensors 11, 12, 13 adopt grating rulers. Taking the Z-direction displacement sensor 13 as an example, it mainly includes the Z-direction grating reading head transition piece 13a, the Z-direction grating reading head 13b, and the Z-direction glass grating scale 13c. The Z-direction grating reading head transition piece 13a provides Z-direction grating reading Mounting structure of the head 13b. When the grating ruler is working, the Z-direction grating reading head 13b can detect the relative displacement between it and the Z-direction glass grating ruler 13c, and send it to the controller 19 through the signal wire.

X, Y, Z direction limit switches 14, 15, 16 adopt Hall type limit switches. Taking the Z-direction limit switch 16 as an example, it mainly includes components such as a Z-direction limit block 16a, a Z-direction Hall switch 16b, and a Z-direction limit switch transition piece 16c. The two Z-direction Hall switches 16b are installed back to back, and the two Z-direction limit blocks 16a are made of metal materials, and are installed opposite to the sensitive end of the Z-direction Hall switch 16b. The Z-direction limit switch transition piece 16c provides a mounting structure for the Z-direction Hall switch 16b. When the limit switch is working, when the Z-direction Hall switch 16b is close to the Z-direction limit block 16a, the Z-direction Hall switch 16b gives a limit signal and sends it to the controller 19 through the signal wire.

In this embodiment, the Z-direction voice coil motor 10 , the Z-direction displacement sensor 13 and the Z-direction limit switch 16 are installed between the piston cylinder 5 and the sleeve 6 and inside the piston cylinder 5 .

The load bearing of the vibration isolator is realized in the following manner: the clean compressed air source 3 delivers clean compressed air to the piston cylinder 5 through the air pipe 26 , the electromagnetic valve 18 and the air inlet 23 . The controller 19 controls the opening of the solenoid valve 18 according to the feedback signal from the gas pressure sensor 17, and adjusts the gas flow rate input into the piston cylinder 5, thereby adjusting the pressure of the clean compressed air in the piston cylinder 5, so that the clean compressed air acts on the piston cylinder. 5. The upward force is balanced with the load, the piston cylinder 5 and the load and the gravity of other parts on the piston cylinder 5, so as to realize the ideal gravity compensation and zero-stiffness vibration isolation effect.

In this embodiment, the pressure of the clean compressed air in the piston cylinder 5 is 0.4MPa, and the effective radius of the lower surface of the piston cylinder 5 is 100mm, so the mass carried by a single vibration isolator is: m=p×πr ² /g≈1282kg, Where p is the gas pressure, p=0.4MPa, r is the effective radius of the lower surface of the piston barrel 5, r=100mm, g is the acceleration of gravity, g=9.8m/s ² .

FIG. 2 shows an embodiment of a plain spherical plain bearing. The sliding joint bearing 7 is mainly composed of a bearing body 7a and a bearing seat 7b. The concave spherical surface on the bearing seat 7b and the convex spherical surface on the bearing body 7a form a sliding motion pair, which is lubricated by liquid or solid lubricant, and the upper and lower mounting plates The degrees of freedom of angular motion between 1 and 2 are decoupled.

FIG. 3 shows another embodiment of the plain spherical plain bearing. The sliding joint bearing 7 is mainly composed of a bearing body 7a and a bearing seat 7b. The bearing seat 7b has a convex spherical surface, and the concave spherical surface on the bearing body 7a constitutes a sliding motion pair, which is lubricated with a liquid or solid lubricant. The degrees of freedom of angular motion between plates 1 and 2 are decoupled.

Figure 5 shows an embodiment of the orifice on the plane air bearing surface of the sleeve. In this embodiment, eight orifice holes 24 on the plane air-floating surface are uniformly distributed around the center of the circle on the lower surface of the sleeve 6 along the circumferential direction, with a diameter of φ0.2 mm.

Figure 6 shows an embodiment of the orifice on the cylindrical air bearing surface on the piston cylinder. In this embodiment, two rows of orifice holes 25 on the cylindrical air-floating surface are evenly distributed along the circumferential direction on the side wall of the piston cylinder 5, and the number of orifice holes 25 on each row of cylindrical air-floating surface is 8, with a diameter of φ0.2mm.

An embodiment of the Z-direction electromagnetic damper is given below in conjunction with FIG. 7 and FIG. 9 . In this embodiment, the vibration isolator has two Z-direction electromagnetic dampers 42, which are composed of a Z-direction permanent magnet 42A array installed on the side wall of the outer cylindrical surface of the piston cylinder 5. The piston cylinder 5 is made of No. 45 steel material, which has a high The magnetic permeability is high, and the sleeve 6 is made of copper material, which is non-magnetic and has high electrical conductivity. The Z-direction permanent magnet 42A is bar-shaped, arranged along the driving force direction of the Z-direction voice coil motor 10 , that is, the axial direction of the piston cylinder 5 , the magnetic pole direction is perpendicular to the outer cylindrical surface of the piston cylinder 5 , and N and S poles are alternately arranged. When the sleeve 6 and the piston cylinder 5 move relative to each other in the Z direction, the sleeve 6 cuts the lines of magnetic force to generate eddy current and damping force, and the Z direction damping force is proportional to the relative movement speed of the sleeve 6 and the piston cylinder 5 in the Z direction, and Consistent with the direction of the driving force of the Z-direction voice coil motor 10, the purpose of consuming vibration energy and improving positioning stability is achieved.

7 and 10 show another embodiment of the Z electromagnetic damper. In this embodiment, the vibration isolator has four Z-direction electromagnetic dampers 42 , which are composed of an array of Z-direction permanent magnets 42A installed on the side wall of the outer cylindrical surface of the piston barrel 5 . The Z-direction permanent magnet 42A is bar-shaped, arranged along the driving force direction of the Z-direction voice coil motor 10 , that is, the axial direction of the piston cylinder 5 , the magnetic pole direction is perpendicular to the outer cylindrical surface of the piston cylinder 5 , and N and S poles are alternately arranged.

An embodiment of the X and Y direction electromagnetic dampers is given below in conjunction with Fig. 8 and Fig. 11 . In this embodiment, the vibration isolator has two X-direction electromagnetic dampers 40 and two Y-direction electromagnetic dampers 41, which are respectively composed of arrays of X- and Y-direction permanent magnets 40A and 41A installed on the side walls of the upper surface of the lower mounting plate 2 , The lower mounting plate 2 is made of No. 45 steel material with high magnetic permeability, and the sleeve 6 is made of red copper material, which is non-magnetic and has high electrical conductivity. The permanent magnets 40A and 41A in the X and Y directions are elongated, arranged along the driving force directions of the voice coil motors 8 and 9 in the X and Y directions respectively, the direction of the magnetic poles is perpendicular to the upper surface of the lower mounting plate 2, and the N and S poles alternate layout. When the sleeve 6 and the lower mounting plate 2 move relative to each other, the sleeve 6 cuts the lines of magnetic force to generate eddy currents and damping forces, and the damping force in the X and Y directions is related to the relative movement of the sleeve 6 and the lower mounting plate 2 in the X and Y directions. The speed is directly proportional, and the direction is consistent with the driving force directions of the X and Y direction voice coil motors 8 and 9, so as to achieve the purpose of consuming vibration energy and improving positioning stability.

Fig. 8 and Fig. 12 show another embodiment of the X and Y direction electromagnetic dampers. In this embodiment, the vibration isolator has an X-direction electromagnetic damper 40 and a Y-direction electromagnetic damper 41 , which are respectively composed of arrays of X- and Y-direction permanent magnets 40A and 41A installed on the sidewall of the upper surface of the lower mounting plate 2 . The permanent magnets 40A and 41A in the X and Y directions are elongated, arranged along the driving force directions of the voice coil motors 8 and 9 in the X and Y directions respectively, the direction of the magnetic poles is perpendicular to the upper surface of the lower mounting plate 2, and the N and S poles alternate layout.

Claims (8)

1. An electromagnetic damping zero-stiffness vibration isolator with angular decoupling of sliding joint bearings, consisting of an upper mounting plate (1), a lower mounting plate (2), a clean compressed air source (3), an air pipe (26) and a vibration isolator The vibration isolator body (4) is installed between the upper mounting plate (1) and the lower mounting plate (2), and the clean compressed air source (3) is connected to the vibration isolator body (4) through the gas pipe (26). ) connection, characterized in that: in the structure of the vibration isolator main body (4), the lower surface of the sleeve (6) and the lower mounting plate (2) are lubricated and supported by the axial bearing plane air bearing surface (21), and the piston The sleeve (5) is installed undercut in the sleeve (6), and is lubricated and supported with the sleeve (6) through the radial bearing cylindrical air bearing surface (22). The sliding joint bearing (7) is installed in the piston sleeve (5) and Between the upper mounting plate (1), the Z direction voice coil motor (10), the Z direction displacement sensor (13), and the Z direction limit switch (16) are installed between the piston cylinder (5) and the sleeve (6), X-direction voice coil motor (8), X-direction displacement sensor (11), X-direction limit switch (14) and Y-direction voice coil motor (9), Y-direction displacement sensor (12), Y-direction limit switch (15 ) is installed between the sleeve (6) and the lower mounting plate (2); the driving force direction of the Z-direction voice coil motor (10) is the vertical direction, and the X-direction voice coil motor (8) and the Y-direction voice coil motor ( 9) The direction of the driving force is in the horizontal plane and perpendicular to each other, and the directions of the action lines of the X, Y, and Z direction displacement sensors (11, 12, 13) and the X, Y, and Z direction limit switches (14, 15, 16) are the same as X, Y, Z direction voice coil motors (8, 9, 10) have the same driving force direction; X, Y, Z direction displacement sensor (11, 12, 13) and X, Y, Z direction limit switch (14, 15,16) are connected with the signal input end of controller (19) respectively, and the signal output end of controller (19) is connected with the signal input end of driver (20), and the signal output end of driver (20) is connected with X, Y respectively. , Z-direction voice coil motor (8, 9, 10) connection; X-direction permanent magnet (40A) is installed on the upper surface side wall of the lower mounting plate (2) along the X-direction voice coil motor (8) driving force direction to form X-direction electromagnetic damping device (40), the upper surface side wall of the lower mounting plate (2) is installed along the Y direction to the driving force direction of the voice coil motor (9) to the Y direction permanent magnet (41A) to form the Y direction electromagnetic damper (41), in the piston barrel (5 ) The side wall of the outer cylindrical surface is installed along the direction of the driving force of the Z-direction voice coil motor (10) to form a Z-direction permanent magnet (42A) to form a Z-direction electromagnetic damper (42), and X and Y are directed to the magnetic pole directions of the permanent magnets (40A, 41A) perpendicular to the upper surface of the lower mounting plate (2), and the N and S poles are arranged alternately, the magnetic pole direction of the Z-direction permanent magnet (42A) is perpendicular to the outer cylindrical surface of the piston barrel (5), and the N and S poles are arranged alternately, The piston cylinder (5) and the lower mounting plate (2) are made of ferromagnetic material, and the sleeve (6) is made of a nonmagnetic good conductor material. 2. The electromagnetic damping zero-stiffness vibration isolator with angular decoupling of sliding joint bearings according to claim 1, characterized in that: the piston cylinder (5) is provided with a gas pressure sensor (17), and the piston cylinder (5) An air inlet (23) and a solenoid valve (18) are arranged on the top, the gas pressure sensor (17) is connected with the signal input end of the controller (19), and the signal output end of the controller (19) is connected with the signal of the driver (20). The input end is connected, and the signal output end of the driver (20) is connected with the solenoid valve (18). 3. The electromagnetic damping zero-stiffness vibration isolator with angular decoupling of the sliding joint bearing according to claim 1, characterized in that: the X, Y, and Z direction voice coil motors (8, 9, 10) are cylindrical Voice coil motor or flat type voice coil motor. 4. The electromagnetic damping zero-stiffness vibration isolator for sliding joint bearing angle decoupling according to claim 1, characterized in that: the X, Y, and Z direction displacement sensors (11, 12, 13) are grating rulers, magnetic scale, capacitive scale or linear potentiometer. 5. The electromagnetic damping zero-stiffness vibration isolator with angular decoupling of the sliding joint bearing according to claim 1, characterized in that: the X, Y, and Z direction limit switches (14, 15, 16) are mechanical limit switches. Position switch, hall limit switch or photoelectric limit switch. 6. The electromagnetic damping zero-stiffness vibration isolator with angular decoupling of sliding joint bearings according to claim 1, characterized in that: the gas pressure in the piston cylinder (5) is 0.1 MPa-0.8 MPa. 7. The electromagnetic damping zero-stiffness vibration isolator with angular decoupling of the sliding joint bearing according to claim 1, characterized in that: the axial bearing plane air bearing surface (21) and the radial bearing cylindrical air bearing surface (22) The thickness of the gas film is 10 μm to 20 μm. 8. The electromagnetic damping zero-stiffness vibration isolator of sliding joint bearing angle decoupling according to claim 1, characterized in that: the cylindrical air bearing surface throttle hole (25) and the sleeve ( 6) The diameter of the orifice (24) on the plane air bearing surface is φ0.1mm～φ1mm.