CN113291825A

CN113291825A - Precise air floatation platform

Info

Publication number: CN113291825A
Application number: CN202110549132.XA
Authority: CN
Inventors: 王绍凯; 蒋荷洁; 史维佳; 谭久彬
Original assignee: Harbin Institute of Technology
Current assignee: Harbin Institute of Technology
Priority date: 2021-05-20
Filing date: 2021-05-20
Publication date: 2021-08-24

Abstract

The invention relates to a precise air-floating platform, belonging to the technical field of transportation devices, wherein the air-floating platform comprises one or more parallel supporting surfaces, and each supporting surface comprises a positive pressure unit and a negative pressure unit; the positive pressure unit comprises a pressure outlet which provides pressurized gas and is used for generating a supporting gas film for supporting a carried object; the negative pressure unit comprises a pressure inlet, the pressure inlet provides a pressure value lower than the ambient pressure, and the adsorption pressure opposite to the supporting air film is generated; and an atmosphere communication groove is surrounded around each positive pressure unit and each negative pressure unit, and the atmosphere communication groove locally discharges the mass flow of the pressure outlet or locally provides the mass flow of the pressure inlet, so that the pressure at the atmosphere communication groove is kept at the ambient pressure. By adopting the technical scheme, the thin flexible object can be stably, reliably and contactlessly suspended on the air floatation platform, and low-friction, high-precision, lossless and efficient supporting, transporting, detecting and processing are realized.

Description

Precise air floatation platform

Technical Field

The invention belongs to the technical field of transportation devices, and particularly relates to a precise air floatation platform.

Background

The transportation means includes conventional contact transportation and non-contact transportation. Among them, there are many problems in the conventional contact transportation, such as: mechanical damage, contact contamination, ESD, contact deformation, temperature gradients, etc. Meanwhile, along with the size enlargement and lightening of the transported object (such as a silicon wafer, an LCD glass substrate, an FPD and the like), the requirements on the transportation stability, reliability and processing precision are higher and higher, and the lossless, reliable and efficient transportation and detection difficulty are gradually improved. The traditional contact type transportation can not meet the application requirements of increasingly developed technologies such as precision manufacturing, precision measurement, precision transportation and the like, and the non-contact transportation device is produced at the same time.

The non-contact transportation technology which is applied and researched more at present mainly comprises the following steps: electrostatic suspension, magnetic suspension, ultrasonic suspension, and pneumatic suspension. The electrostatic suspension requires that the carried object is charged to a certain extent; magnetic levitation can only be used to suspend conductors or semiconductors with higher electrical conductivity; ultrasonic levitation devices are complex in construction, extremely costly to manufacture and maintain, and can only support and transport objects of relatively small volume. The static pressure air-float transportation technology in the pneumatic suspension has no requirements for the material, volume, weight and the like of the carried object, has the advantages of simple structure, air cushion homogenization error and the like, and is widely concerned.

The size of the transported object is large, the transported object is light and thin, so that the transported object tends to be a flexible object, when the transported object is supported and transported by using a static pressure air flotation transportation technology, the unreasonable air flotation structure design can generate uneven air cushion pressure, and the flexible object can be placed on the uneven air cushion pressure support to cause large deformation and integral instability of the object, so that the processing and treatment of the object are failed.

In a patent document entitled "high performance non-contact support platform", published in WO2003/060961, a PV-type air cushion is described: a support surface having an arrangement of a plurality of pressure outlets in communication with a high pressure source and pressure inlets in communication with a vacuum source creates an air cushion in which excess air is evacuated by the pressure inlets in communication with the vacuum source. The PV-type air-cushion in this patent locally discharges mass flow through a pressure inlet connected to a vacuum source, which reduces air-cushion pressure blockage at a pressure outlet located inside the air-cushion support surface, so that the peak value of the air-cushion pressure is reduced to obtain a more uniform and stable bi-directional stiffness air-cushion support.

The thesis of construction and optimization of an air flotation module, design and optimization of a negative pressure adsorption type air flotation platform carrying unit and glass substrate deformation research in an air flotation transmission system researches the influence of working conditions and structural parameters of a PV-type air cushion in a high-performance non-contact supporting platform on the air cushion performance and deformation of a thin flexible object through a finite element and experimental method, and the fact that the PV-type air cushion cannot provide a completely uniform bidirectional rigidity air cushion can be known.

The invention provides a method for partitioning by pressure in a high-performance non-contact supporting platform, namely a method for slightly supplying pressure to the edge of an air floating platform than the inside of the air floating platform so as to obtain an air cushion which is uniform and consistent on the whole. The paper "research on deformation of glass substrate in air floatation conveying system" reduces the pressure peak in the central pressure blocking area by increasing the vacuum degree inside the air floatation platform. The two principles are consistent, and the purpose is to smooth the pressure blockage of the internal air cushion area so as to reduce the deformation of the glass substrate. According to the research results of the thesis, after the vacuum degree in the air floating platform is improved, the negative pressure peak value of the pressure inlet in the inner area is increased, the positive pressure peak value of the pressure outlet is slightly reduced, the high and low pressure peak values of the air cushion tend to be uniform slightly, but the pressure peak values of the pressure outlet/pressure inlet at different positions with the same structure and property are still different greatly, the integral bending rigidity of the thin flexible supported object is extremely low, and the uneven load is easy to cause the integral large deformation of the object and the unevenness of the air cushion. This pressure-zonal optimization has limited improvement in pressure blockage and uniformity and locality of the air cushion, while the cost of the pressure-zonal is greatly increased.

Disclosure of Invention

In view of the above problems in the prior art, an object of the present invention is to provide a precise air floating platform, which can suspend a thin flexible object on the air floating platform stably, reliably and contactlessly, and realize low friction, high precision, lossless and efficient supporting, transporting, detecting and processing.

In order to achieve the above object, the present invention provides a technical solution as follows:

a precise air-floating platform comprises an air-floating platform, wherein the air-floating platform comprises one or more supporting surfaces which are parallel to each other, and the supporting surfaces comprise at least one positive pressure unit and at least one negative pressure unit which are arranged in a staggered mode; the positive pressure unit comprises at least one pressure outlet which provides pressurized gas and is used for generating a supporting gas film for supporting a supported object; the negative pressure unit comprises at least one pressure inlet, the pressure inlet provides a pressure value lower than the ambient pressure, and generates an adsorption pressure opposite to the supporting air film; and an atmosphere communication groove is formed around each of the positive pressure unit and the negative pressure unit, and the atmosphere communication groove partially discharges the mass flow of the pressure outlet or partially provides the mass flow of the pressure inlet, so that the pressure at the atmosphere communication groove is kept at the ambient pressure.

Preferably, the air floating platform is provided with vent holes at intervals, one end of each vent hole is communicated with the atmosphere communication groove, and the other end of each vent hole is positioned on the outer side of the supporting surface and is communicated with ambient air pressure fluid.

Preferably, a high-pressure air cavity channel is arranged in the air floatation platform, and each pressure outlet is communicated with the high-pressure air cavity channel through an arranged pressure restrictor; and a high-pressure source communicated with the high-pressure air cavity channel is arranged on the outer side of the air floatation platform.

Preferably, a vacuum air cavity channel is arranged in the air floatation platform, and each pressure inlet is communicated with the vacuum air cavity channel through an arranged vacuum restrictor; a vacuum restrictor is arranged between the pressure inlet and the vacuum air cavity channel; the throttling effect of the pressure throttling device is higher than that of the vacuum throttling device.

Preferably, a shallow vacuum groove is provided on the support surface at the pressure inlet.

Preferably, the support surfaces comprise at least one central support surface and at least one edge support surface which are mutually spliced; the pressure subarea is arranged at the local position of the middle supporting surface or the edge supporting surface, and the positive pressure unit and the negative pressure unit are respectively arranged in the pressure subarea.

Preferably, the resultant force of the positive pressure units in the pressure subareas is greater than the resultant force of the negative pressure units in the pressure subareas, and the resultant force of the positive pressure units and/or the negative pressure units in the pressure subareas is respectively less than or greater than the resultant force of the positive pressure units and/or the negative pressure units outside the pressure subareas.

Preferably, the resolution of the positive pressure unit and the negative pressure unit in the pressure subarea is smaller or larger than the resolution of the positive pressure unit and the negative pressure unit outside the pressure subarea.

Preferably, the pressure partition includes a plurality of the positive pressure units or the negative pressure units.

Preferably, the resultant force of the positive pressure unit and/or the negative pressure unit is 5-80 times of the gravity value of the corresponding area of the loaded object.

In summary, the precise air floating platform provided by the invention has the following beneficial effects:

1. the precise air floating platform can not only provide high-precision support and transportation for large-size thin flexible objects, but also be used as an air floating transportation platform for rigid objects.

2. The air cushion 500 formed by the precise air floating platform has the property of bidirectional rigidity, and the property can ensure that an object has the bidirectional rigidity of compression resistance and tensile resistance at the same time, and is stably supported and transported with high precision.

3. The air cushion 500 formed by the precise air floating platform of the invention has self-adaptive property, which can lead the air cushion 500 to adjust the resultant force of the air cushion 500 in a self-adaptive way, resist the influence of the fluctuation in different directions on the object and lead the object to be stably kept at the thickness of a balance air cushion 500.

4. The air cushion 500 formed by the precise air-floating platform has the characteristics of uniformity and locality, the characteristics can ensure the stability and the flatness of the object in the supporting and transporting processes, and the risk of the contact and collision of the object with the supporting surface under the critical condition in the supporting and transporting processes is reduced.

5. The air cushion 500 formed by the precise air floating platform has the property of negative pressure delayed adsorption, and the property can delay the adsorption effect of negative pressure on an object, ensure the safety of the object transportation process and prevent the front edge of the object from contacting or colliding with a supporting surface downwards.

6. The air cushion 500 formed by the precise air floating platform has the properties of bidirectional rigidity, self-adaption, negative pressure delayed adsorption, uniformity and locality, can stably and reliably suspend the thin flexible object on the air floating platform, realizes low-friction, high-precision, nondestructive and efficient transportation and detection, and can flatten the thin flexible object which is not flat.

7. The precise air-floating platform of the present invention can be applied to the fields of non-horizontal transportation (e.g., vertical transportation, inclined transportation), turning, loading and unloading (air pressure loading/unloading by controlling the vacuum adsorption of the negative pressure unit 200), etc., in addition to the up-and-down horizontal support and transportation.

Drawings

FIG. 1 is a schematic plan view of a precise air-floating platform according to the present invention;

FIG. 2 is a schematic plan view of a protruded positive pressure unit/negative pressure unit in a precise air floating platform according to the present invention;

FIG. 3 is an isometric view of an air bearing platform comprised of a single raised support surface of a precision air bearing platform according to the present invention;

FIG. 4 is a schematic view of a shallow protruded vacuum groove in a precision air floating platform according to the present invention;

FIG. 5 is a plan view of an air bearing platform constructed with a plurality of raised support surfaces according to the present invention;

FIG. 6 is a graph showing the behavior of the air bearing at different states in section A-A of FIG. 1 in a precision air-bearing platform according to the present invention;

FIG. 7 is a graph illustrating the behavior of an air bearing, highlighted as section B-B in FIG. 1, in a precision air bearing platform of the present invention at equilibrium;

FIG. 8 is a modified view of the air cushion supported load of the present invention;

FIG. 9 is a plan view of a PV type air cushion in a prior art "high Performance non-contact support platform";

FIG. 10 is a graph highlighting the air cushion behavior at section C-C in FIG. 9;

figure 11 is a graph highlighting the behavior of the air spring of section D-D in figure 9 at equilibrium.

Reference numbers in the figures:

100. a positive pressure unit; 110. a pressure outlet; 200. a negative pressure unit; 210. a pressure inlet; 220. vacuum shallow grooves are formed; 300. an atmosphere communicating groove; 310. a vent hole; 400. a supported object; 500. an air cushion; 600. a high pressure air cavity channel; 700. a vacuum air cavity channel; 800. a support surface;

100 ', a positive pressure unit'; 110. a pressure outlet; 200 ', a negative pressure unit'; 210. a pressure inlet;

fa-is the force of a single positive pressure unit/unit' pulling the object away from the support surface;

fv-is the force of a single negative pressure unit/negative pressure unit' on the object to push against the support surface;

pa-is the air cushion pressure of the positive pressure unit/positive pressure unit';

pv-is the air cushion vacuum pressure of the negative pressure unit/negative pressure unit'.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Examples

The invention provides a precise air-floating platform, which is shown in figures 1-8 and comprises an air-floating platform, wherein the air-floating platform comprises one or more supporting surfaces 800 which are parallel to each other, and the supporting surfaces 800 comprise at least one positive pressure unit 100 and at least one negative pressure unit 200 which are arranged in a staggered mode.

The positive pressure unit 100 includes at least one pressure outlet 110, and the pressure outlet 110 provides pressurized gas and is used to generate a supporting gas film for supporting the supported object 400. The negative pressure unit 200 comprises at least one pressure inlet 210, the pressure inlet 210 providing a pressure value below ambient pressure, creating a suction pressure opposite to the supporting air film. An atmosphere communication groove 300 is surrounded around each of the positive pressure unit 100 and the negative pressure unit 200, and the atmosphere communication groove 300 partially discharges the mass flow of the pressure outlet 110 or partially supplies the mass flow of the pressure inlet 210, so that the pressure at the atmosphere communication groove 300 is maintained at the ambient pressure.

During operation, the positive pressure unit 100 provides pressurized air for generating an air film for supporting the object 400 to make the object 400 have a certain compressive rigidity when suspended above the air film, and the negative pressure unit 200 provides a certain negative pressure to generate an adsorption pressure opposite to the air film on the object 400 to make the object 400 have a tensile rigidity when supported and transported without contact. Through the arranged atmosphere communicating groove 300, the flow field of each positive pressure unit 100 or negative pressure unit 200 is kept relatively independent, the stress of the large flat borne object 400 tends to be bidirectionally and uniformly distributed in the range of the whole air cushion 500, and the phenomenon that the borne object 400 is integrally deformed greatly due to the concentrated load of each positive pressure unit 100 and each negative pressure unit 200, so that the borne object 400 is integrally unstable and has uneven thickness of the air cushion 500 is avoided.

The surfaces of the positive pressure unit 100 and the negative pressure unit 200 may be rectangular, circular, prismatic or other shapes.

Further, a high-pressure air cavity channel 600 is arranged in the air floating platform, and each pressure outlet 110 is communicated with the high-pressure air cavity channel 600 through an arranged pressure restrictor. One positive pressure unit 100 may include one pressure outlet 110, or may include a plurality of pressure outlets 110. And the high-pressure air chamber channel 600 is communicated with one positive pressure unit 100 or communicated with the pressure outlets 110 of a plurality of positive pressure units 100 through the arranged pressure throttler, so that the positive pressure units 100 in partial areas can provide balanced pressurized air. Meanwhile, a high pressure source communicated with the high pressure air cavity channel 600 is arranged outside the air floating platform. The high-pressure source may be a high-pressure reservoir or other high-pressure gas injection device, but is not limited thereto.

The air floating plate is internally provided with a vacuum air cavity channel 700, and each pressure inlet 210 is communicated with the vacuum air cavity channel 700 through the arranged vacuum restrictor. Wherein, one negative pressure unit 200 may include one pressure inlet 210, or may include a plurality of pressure inlets 210, and the vacuum air chamber channel 700 is connected to the pressure inlet 210 of one negative pressure unit 200 or a plurality of negative pressure units 200 through the arranged vacuum throttler. And a vacuum source communicated with the vacuum air cavity channel 700 is arranged on the outer side of the air floating platform. The vacuum source may be a vacuum reservoir or other vacuum pumping device, but is not limited thereto.

The throttling effect of the pressure throttling device is higher than that of the vacuum throttling device.

It should be noted that the pressure levels of the high pressure source and the vacuum source are controlled at least in selected sections of the high pressure source and the vacuum source to locally adjust and control the thickness of the air cushion 500 and keep the supported object 400 parallel with respect to an independent reference.

The pressure restrictor and/or the vacuum restrictor may be provided in various throttling manners such as orifice throttling, slit throttling, surface throttling, variable throttling, or porous throttling, but not limited thereto.

Further, a vacuum shallow groove 220 is disposed on the air floating platform and at the pressure inlet 210, wherein the depth of the vacuum shallow groove 220 is less than 1mm, and the shape of the vacuum shallow groove 220 may be circular, square, diamond, or other shapes, but is not limited thereto. The vacuum shallow groove 220 is arranged for delaying the action of vacuum adsorption pressure.

When the thin flexible substrate 400 is supported or transported on the air cushion 500, the substrate 400 will only receive a small absorption force of the shallow vacuum groove 220 to be covered before the front edge of the thin substrate 400 completely covers the shallow vacuum groove 220, compared to that, when the pressure outlet 110 just covered by the front edge of the substrate 400 has a large positive pressure on the substrate 400, the front edge of the substrate 400 will slightly rise until the shallow vacuum groove 220 is completely covered. This is because the ambient air flows into the shallow grooves 220 before the front edge of the supported object 400 completely covers the shallow grooves, and the vacuum pressure on the edge is reduced, so that the resultant force applied to the front edge of the supported object 400 is in the direction of pulling away the support surface 800. This property can delay the absorption of the load 400 by the negative pressure, ensure the safety of the transportation process of the load 400, and prevent the front edge of the load 400 from contacting or colliding with the supporting surface 800.

After calculating or actually measuring the size of the atmosphere communication groove 300 according to the structure and size of the air floating platform, the structure and size of the positive pressure unit 100/negative pressure unit 200, the type and size of the restrictor, the pressure condition, and other variables, a proper width value is designed to ensure that the mass flow of the pressure outlet 110/pressure inlet 210 is only discharged/supplied by the atmosphere communication groove 300, and the pressure is kept at the ambient pressure at the position of the atmosphere communication groove 300. And on the premise of realizing the above functions, the width of the atmosphere communicating groove 300 is not too large, so as to ensure that the bearing area of the positive pressure unit 100/the negative pressure unit 200 is enough to provide compressive rigidity/tensile rigidity for the carried object 400.

Preferably, the air floating platform is provided with air vents 310 at intervals, one end of the air vent 310 is communicated with the atmosphere communicating groove 300, and the other end is positioned outside the supporting surface 800 and is in fluid communication with the ambient air pressure. On the supporting surface 800, the atmosphere communicating groove 300 in the middle is relatively poor in fluid communication with the ambient air pressure compared with the atmosphere communicating groove 300 in the edge position, and the atmosphere communicating groove 300 can be enhanced to be in fluid communication with the ambient air pressure through the vent hole 310, so that the pressure in the atmosphere communicating groove 300 is ensured to be the ambient pressure. If the pressure of the atmosphere communication groove 300 in the support surface 800 can be secured to the ambient pressure even in the case where the vent hole 310 is not present after the actual measurement, the vent hole 310 may not be provided.

The shape of the support surface 800 may be a flat surface, a cylindrical surface, or other surface, without limitation, and the shape of the support surface 800 may be rectangular, circular, or other shape.

The support surface 800 includes at least one central support surface and at least one edge support surface that are spliced to each other. When multiple support surfaces 800 are provided, the edge support surfaces may surround the central support surface, the central support surface may be located in the center of the air bearing platform, and the edge support surfaces may be located at the edges of the air bearing platform. It should be noted that, when the supporting surfaces 800 are spliced together, the shape and position of each supporting surface 800 are not limited, that is, the shape may be rectangular, circular or other shapes, and may also be flat, curved or toric, and the distribution position of each supporting surface 800 is not limited to the above-mentioned middle edge and middle position distribution.

The pressure subarea is arranged on the local part of the middle supporting surface or the edge supporting surface, and the positive pressure unit and the negative pressure unit are respectively arranged in the pressure subarea. The pressure subarea is used as a compensation technology to adjust the problem of local unevenness of a supported object caused by various reasons, and the following parameters can be adjusted in the pressure subarea: resolution, pressure values of the positive pressure units/negative pressure units, and the number of the positive pressure units/negative pressure units. The method comprises the following specific steps:

in one embodiment, the resultant force of the positive pressure units in the pressure subareas is greater than the resultant force of the negative pressure units in the pressure subareas, and the resultant force of the positive pressure units and/or the negative pressure units in the pressure subareas is respectively less than or greater than the resultant force of the positive pressure units and the negative pressure units outside the pressure subareas.

In one embodiment, the resolution of the positive pressure unit and/or the negative pressure unit in the pressure partition is smaller or larger than the resolution of the positive pressure unit and the negative pressure unit outside the pressure partition, respectively. Wherein, the above "resolution" refers to the number of the positive pressure units 100 and the negative pressure units 200 on the air floating platform with the same size.

In one embodiment, the pressure zones comprise a plurality of positive pressure units or negative pressure units.

For example, a number of positive pressure units 100 and a number of negative pressure units 200 are included on the edge support surface. The pressure value of the positive pressure unit 100/negative pressure unit 200 at the edge support surface 800 is less than the pressure value at the middle support surface 800; the positive pressure unit 100 and the negative pressure unit 200 have a resolution at the edge support surface 800 that is greater than a resolution at the middle support surface 800. Under the condition that the size of the supporting plane is the same, the smaller the size of the positive pressure unit 100 and the negative pressure unit 200 is, the larger the number is, the higher the resolution is, the higher the rigidity of the carried object 400 is, the better the uniformity is, and the smaller the deformation generated in the process of being supported and transported is. In order to reduce the supporting cost, a high-resolution positive pressure unit 100 and a low-resolution negative pressure unit 200 are provided on a middle supporting surface 800, and a high-resolution positive pressure unit 100 and a high-resolution negative pressure unit 200 are provided on an edge supporting surface 800, in order to reduce the edge effect of the object 400, in an area where the object 400 is required to be inspected/processed with high precision. The edge effect is that the rigidity of the edge or corner of the thin flexible supported object 400, which generates deflection, is smaller than the rigidity of the supported object 400, which generates local deflection, i.e. under the same pressure distribution, the deflection of the edge of the supported object 400 is much larger than the deflection of the inside of the supported object 400.

In a preferred embodiment, the edge support surface 800 includes a plurality of positive pressure units 100 to reduce edge effects of the substrate 400. By the single arrangement of the positive pressure unit 100, the edge contact of the supported object 400 with the supporting surface 800 on the lower side during the transfer process is avoided.

The resultant force of the positive pressure unit 100 and/or the resultant force of the negative pressure unit 200 are 5-80 times the gravity value of the corresponding area of the object 400. The resultant force value of the positive pressure unit 100 is greater than the resultant force value of the negative pressure unit 200, and the difference between the resultant force value of the positive pressure unit 100 and the resultant force value of the negative pressure unit is the gravity of the object 400 to be carried.

By adopting the scheme, the vacuum preloading precise air floating platform is provided, when the carried object 400 is suspended above the air floating platform by the thickness of the small air cushion 500, the air cushion 500 is formed between the carried object 400 and the air floating platform, and the air cushion 500 has the bidirectional rigidity of compression resistance and tensile resistance and is not influenced by the mass of the carried object 400. The supported object 400 can be stably and contactlessly held and the supported object 400 can be accurately supported in a static or conveying way.

The air cushion 500 formed by the air floating platform of the invention has the property of flattening thin and flexible objects which are not flat. According to a preferred embodiment of the present invention, the air cushion 500 of the air floating platform of the present invention has the properties of bidirectional rigidity, self-adaptation, negative pressure delayed adsorption and uniformity, locality. The specific analysis is as follows:

(1) principle of the bi-directional stiffness properties of the air mattress 500:

by bi-directional stiffness is meant that the air cushion 500 is able to force objects back to the equilibrium air cushion 500 gap with a force much greater than the object weight and in a self-adaptive manner during an attempt to push the objects toward the air platform support surface 800 or pull them away from the air platform support surface 800.

The positive pressure units 100 with the same size inside each air floating platform are within a limited range, and the pressure has the same positive pressure distribution around the pressure outlet 110; the negative pressure units 200 with the same size inside each air bearing platform have the same negative pressure distribution around the pressure inlet 210 within a limited range. The limited range refers to a single communication area with the pressure outlet 110/pressure inlet 210 surrounded by the atmospheric communication groove 300, which is a pressure/vacuum occupied area of the basic unit. The force for pulling the object away from the supporting surface 800 formed by the positive pressure unit 100 and the force for pushing the object towards the supporting surface 800 formed by the negative pressure unit 200 are of the same order of magnitude, and the combined force of the positive pressure unit 100 and the negative pressure unit 200 inside the air floating platform is 5-80 times the mass of the corresponding area of the carried object 400. The difference between these two opposing forces offsets the mass of the substrate 400 and stabilizes the substrate 400 at a distance from the support surface 800 of the air bearing platform, which is the thickness of the air bearing 500 under stabilization. The material can make the object have two-way rigidity of compression resistance and tensile resistance at the same time, and the object can be stably supported and transported with high precision. It should be noted that the base unit refers to the positive pressure unit 100 and/or the negative pressure unit 200.

(2) Principle of the adaptive nature of the air cushion 500:

since the throttling effect of the pressure restrictor of the pressure outlet 110 is significantly higher than that of the vacuum restrictor of the pressure inlet 210, the air cushion 500 can show the variation of the pulling force or pushing force of the air cushion 500 to the object when the carried object 400 deviates from the thickness of the stabilizing air cushion 500 by different distances. When the distance between the carried object 400 and the supporting surface 800 is less than the thickness of the stabilizing air cushion 500, the pressure of the positive pressure unit 100 and the pressure of the negative pressure unit 200 both tend to increase, but the difference of the throttling effect causes the positive pressure stored by the pressure throttling device to be released more than the negative pressure stored by the vacuum throttling device, the pressure of the positive pressure unit 100 increases more rapidly, and the negative pressure unit 200 only slightly increases, so the force for pulling the carried object 400 away from the supporting surface 800 is generally expressed; when the distance between the supported object 400 and the supporting surface 800 is larger than the thickness of the stabilizing air cushion 500, the pressure of the positive pressure unit 100 and the pressure of the negative pressure unit 200 both decrease, but the difference of the throttling effect causes the pressure throttling device to store more positive pressure than the vacuum throttling device, the pressure of the positive pressure unit 100 decreases more rapidly, and the pressure of the negative pressure unit 200 decreases more slowly, so the force pushing the supported object 400 to the supporting surface 800 is generally expressed. This behavior manifests the bi-directional stiffness and adaptive nature of the air bearing 500 of the inventive air bearing platform. This feature enables the air cushion 500 to adjust the resultant force of the air cushion 500 in a self-adaptive manner, and resists the influence of the fluctuation and deviation in different directions on the object, so that the object is stably maintained at a balanced air cushion 500 thickness.

(3) Principle of negative pressure delayed adsorption of the air cushion 500:

according to a preferred embodiment of the present invention, the basic units in a row perpendicular to the walking direction are the positive pressure units 100 and the negative pressure units 200 distributed alternately, and the negative pressure units 200 are provided with a sunken vacuum shallow groove 220 on the surface thereof opposite to the center of the pressure inlet 210, wherein the sunken vacuum shallow groove is a long rectangle parallel to the walking direction for delaying the action of the vacuum suction pressure. When the thin flexible substrate 400 is supported or transported on the air cushion 500, the substrate 400 will only receive a small absorption force of the shallow vacuum groove 220 to be covered before the front edge of the thin substrate 400 completely covers the shallow vacuum groove 220, compared to that, when the pressure outlet 110 just covered by the front edge of the substrate 400 has a large positive pressure on the substrate 400, the front edge of the substrate 400 will slightly rise until the shallow vacuum groove 220 is completely covered. This is because the ambient air flows into the shallow grooves 220 before the front edge of the supported object 400 completely covers the shallow grooves, and the vacuum pressure on the edge is reduced, so that the resultant force applied to the front edge of the supported object 400 is in the direction of pulling away the support surface 800. This property can delay the absorption of the load 400 by the negative pressure, ensure the safety of the transportation process of the load 400, and prevent the front edge of the load 400 from contacting or colliding with the supporting surface 800.

(4) Principle of uniformity and local properties of the air cushion 500:

the basic unit is established by surrounding the pressure outlet 110 or the pressure inlet 210 with the atmospheric communication groove 300, and the positive pressure unit 100 and the negative pressure unit 200 are distributed substantially in a staggered arrangement. The atmosphere communication groove 300 functions as:

a. the mass flow for the local discharge pressure outlet 110 or the mass flow for the local supply pressure inlet 210, where the pressure is maintained at ambient pressure, causes the flow field to transition locally gently from high/low pressure to low/high pressure, and the flat flexible substrate 400 to transition locally gently from a deflection away from/towards the support surface 800 to a deflection towards/away from the support surface.

b. Each positive pressure unit 100/negative pressure unit 200 can balance force and moment locally, so that the stress of a large flat object tends to be distributed with load in two directions in the range of the whole air cushion 500, and the phenomenon that the whole borne object 400 is greatly deformed due to the concentrated load of each basic unit, which is inconsistent, and the whole body of the object is unstable and uneven thickness of the air cushion 500 is avoided.

c. Each positive pressure unit 100/negative pressure unit 200 with the same size has the same positive pressure/negative pressure distribution and peak value within a limited range, so that the problems of poor flatness of the supported object 400 and large thickness change of the air cushion 500 caused by the difference of the pressure distribution and the pressure peak value due to different positions of the pressure outlet 110 and the pressure inlet 210 are avoided, and the supported object 400 can keep stable and uniform thickness of the air cushion 500.

d. When the thin object fluctuates locally due to a critical condition or the like, and the thickness of the air cushion 500 changes, no matter whether the positive pressure/negative pressure of the basic unit is increased or decreased or is in a balanced state, the pressure extends to the boundary of the communication groove all the time, namely, the pressure is transited to the ambient pressure locally, more importantly, the occupied area limited by the single positive pressure unit 100/negative pressure unit 200 does not change, and the property can enable the thin flexible supported object 400 to keep a preset deformation form all the time.

e. The air floating platform can be divided into a plurality of parallel supporting surfaces 800 along the atmosphere communicating groove 300 and then spliced according to the process convenience or the practical application requirement. Since each basic cell has locality, the division does not affect the uniformity and locality and overall properties of the air cushion 500.

The above a-e can make the thin flat flexible supported object 400 generate three-dimensional wave-like undulation on a plane. Compared with the single trend deflection deformation without fluctuation generated by a thin flexible object, the regular wavy deflection deformation can greatly increase the rigidity of the object, maintain the stability and the flatness of the object in the supporting and transporting process and reduce the contact collision risk of the object with the supporting surface 800 under the critical condition in the supporting and transporting process. Among them, the critical situations include: the object is influenced by external forces such as accelerated movement of the clamping device; the transient effect of the additional weight of the object; a transition process of an object from one equilibrium state to another; unstable or fluctuating supply pressure.

If each basic cell is not surrounded by the atmosphere communication groove 300, the following occurs:

if each elementary cell does not have the mass flow of the partial supply/discharge pressure inlet 210/pressure outlet 110 of the atmospheric communication tank 300, the mass flow provided by the pressure outlet 110 is partially discharged by the pressure inlet 210 connected to the vacuum source inside the air bearing platform support surface 800. The air cushion 500 thus produced has different pressure peaks and pressure distributions near the pressure peaks, even though the pressure outlets 110 have the same structure and properties. Only 4 narrow rectangular boundaries around the supporting surface 800 are connected to the ambient air pressure, so that the pressure outlet 110 in the central region of the supporting surface 800 is blocked by the pressure to form a high-pressure region, and even if the vacuum pressure inlet 210 is provided on the air floating platform for discharging the mass flow locally, the peak value of the pressure blockage in the high-pressure region is reduced. The pressure in the area of the air cushion 500 inside the support surface 800 is greater than the pressure in the area of the edge air cushion 500, and meanwhile, due to the interaction between the positive pressure and the negative pressure, the negative pressure in the central area is smaller, and the negative pressure in the peripheral area is larger, so that a completely uniform two-way stiffness air cushion 500 cannot be provided.

In the background art, a PV-type air cushion is described in the patent document entitled "high performance non-contact support platform": a support surface having an arrangement of a plurality of pressure outlets in communication with a high pressure source and pressure inlets in communication with a vacuum source creates an air cushion in which excess air is evacuated by the pressure inlets in communication with the vacuum source. The PV-type air-cushion in this patent locally discharges mass flow through a pressure inlet connected to a vacuum source, which reduces air-cushion pressure blockage at a pressure outlet located inside the air-cushion support surface, so that the peak value of the air-cushion pressure is reduced to obtain a more uniform and stable bi-directional stiffness air-cushion support.

The patent "high performance non-contact supporting platform" proposes a method of pressure partition, i.e. a method of slightly greater pressure supply at the edge than the pressure supply at the inside of the air floating platform, so as to obtain an air cushion with uniform uniformity in the whole. The paper "research on deformation of glass substrate in air floatation conveying system" reduces the pressure peak in the central pressure blocking area by increasing the vacuum degree inside the air floatation platform. The two principles are in agreement, both in order to smooth out the pressure blockage in the area of the internal gas cushion 500 to reduce glass substrate deformation. According to the research results of the thesis, after the vacuum degree in the air floating platform is improved, the negative pressure peak value of the pressure inlet in the inner area is increased, the positive pressure peak value of the pressure outlet is slightly reduced, the high and low pressure peak values of the air cushion tend to be uniform slightly, but the pressure peak values of the pressure outlet/pressure inlet at different positions with the same structure and property are still different greatly, the integral bending rigidity of the thin flexible supported object is extremely low, and the uneven load is easy to cause the integral large deformation of the object and the unevenness of the air cushion. This pressure-zonal optimization has limited improvement in pressure blockage and uniformity and locality of the air cushion, while the cost of the pressure-zonal needs to be increased significantly.

In the present application, when the thickness of the air cushion 500 changes due to local fluctuation of the thin object caused by a critical condition or the like, no matter whether the positive pressure/negative pressure of the basic unit is increased or decreased or is in a balanced state, the pressure extends to the boundary with the atmosphere communication groove 300 all the time, i.e., the pressure is locally transited to the ambient pressure, the occupied area defined by the positive pressure unit 100/the negative pressure unit 200 does not change, and the thin flexible supported object 400 can always maintain a predetermined deformation form due to this property.

If each cell were to eliminate the atmospheric communication channel 300, the area occupied by positive pressure would be similar to, but not exactly equal to, the area occupied by negative pressure when the cushion 500 is in equilibrium. However, when the air cushion 500 deviates from the equilibrium gap due to a critical situation or the like, the peak value and distribution of the positive/negative pressure in the air cushion 500 may change, and the resultant positive and negative pressure forces may change, which, although it helps to enhance the stiffness of the air cushion 500 returning to the equilibrium position, the non-uniform pressure value and the non-uniform area occupied by the positive and negative pressure may also cause the deformation of the thin flexible object and the non-uniform thickness of the air cushion 500.

(5) Air cushion behavior

To further illustrate the performance of the air bearing 500 of the air bearing platform of the present invention, and to compare the performance differences between the PV-type air bearing 500 without atmospheric communication grooves 300 of the basic unit in the "high performance non-contact support platform" patent and the air bearing 500 of the present invention.

As shown in fig. 10, the surface sizes of the basic unit, the positive pressure unit '100' (no atmosphere communicating groove 300) and the negative pressure unit '200' (no atmosphere communicating groove 300) in the patent "high performance non-contact support platform" are completely consistent. As shown in fig. 1, the basic unit, the positive pressure unit 100 (with the atmosphere communicating groove 300) and the negative pressure unit 200 (with the atmosphere communicating groove 300) in the present application have the same surface size, and each basic unit has only one pressure outlet 110/pressure inlet 210, and the restrictor is an orifice.

As shown in fig. 10, the air cushion 500 is formed by alternately arranging the pressure outlets 110 connected to the high pressure source and the pressure inlets 210 connected to the vacuum source in a checkerboard pattern, and the negative pressure unit 200 'and the positive pressure unit 100' of the structure are isolated by the non-atmosphere communicating groove 300.

As shown in FIG. 1, the air cushion 500 of the present application is formed by the staggered arrangement of the pressure outlets 110 connected to the high pressure source and the pressure inlets 210 connected to the vacuum source, and the negative pressure unit 200 and the positive pressure unit 100 of the structure are isolated by the surrounding of the atmosphere communication groove 300.

Fa is the force of the single positive pressure unit 100/positive pressure unit '100' pulling the object away from the support surface 800, Fv is the force of the single negative pressure unit 200/negative pressure unit '200' pushing the object towards the support surface 800, Pa is the pressure of the air cushion 500 of the positive pressure unit 100/positive pressure unit '100', and Pv is the vacuum pressure of the air cushion 500 of the negative pressure unit 200/negative pressure unit '200'. The pressure flows into the air mattress 500 through the pressure restrictor in the pressure outlet 110 (the air mattress 500 is located between the upper surface of the positive pressure unit 100/negative pressure unit 200 and the lower surface of the carried object 400), and the vacuum draws the air in the air mattress 500 out through the vacuum restrictor of the pressure inlet 210.

Referring first to fig. 7, fig. 11, the pressure distribution in cross section a-a (fig. 1) and cross section C-C (fig. 10) is illustrated in three different states: wherein, the a diagram is shifted downwards, the b diagram is kept balanced, and the c diagram is shifted upwards.

Referring to fig. 7 and 11, graph b at equilibrium.

In the air-cushion 500 shown in fig. 11 (air-cushion behavior plot of section C-C in prior art "high performance non-contact support platform"), the pressure introduced is similar to, but not exactly the same as, the active area occupied by the vacuum.

As shown in the air mattress 500 of fig. 7, which is a graph of the air mattress behavior of section a-a of the air mattress 500 of the present invention (fig. 1) in a planar arrangement, the pressure introduced is exactly the same as the active area occupied by the vacuum. The difference in bearing capacity (Fa-Fv) of the positive pressure unit 100 and the negative pressure unit 200 offsets the weight of the object, and thus, such air cushion 500 performs independent of the object weight, whereas Fa and Fv can be significantly greater than the object weight.

The throttling effect of the pressure restrictor of the pressure outlet 110 is required to be significantly higher than that of the vacuum restrictor of the pressure inlet 210, and the air cushion 500 can show the change of the pulling force or pushing force of the air cushion 500 to the object when the carried object 400 deviates from the thickness of the stabilizing air cushion 500 by different distances.

When the air spring 500 is wave deflected downward, less than the thickness of the balanced air spring 500, the pressure restrictor introduces more pressure into the air spring 500 and, at the same time, the vacuum introduced into the air spring 500 by the vacuum restrictor is increased. If the pressure restrictor and the vacuum restrictor are as effective as the restriction, the pressure of the pressure restrictor introduced into the air cushion 500 is of the same order of magnitude as the vacuum of the vacuum restrictor introduced into the air cushion 500, Fa is substantially equal to Fv, i.e., the difference between Fa and Fv is approximately zero, and there is no additional force available to pull the object away from the support surface 800, there is a risk that the object will contact or impact the support surface 800. If the throttling effect of the pressure restrictor is higher than that of the vacuum restrictor, the magnitude of the pressure restrictor introduced into the air cushion 500 is larger than that of the vacuum restrictor introduced into the air cushion 500, Fa is larger than Fv, namely the difference between Fa and Fv is represented as a force for pulling an object away from the supporting surface 800, and the force is far larger than the weight of the object corresponding to the supporting area, so that the air cushion 500 returns to the balance thickness, and the safety distance between the object and the supporting surface is ensured.

When the air spring 500 fluctuates in thickness upward, greater than the equilibrium air spring 500 thickness, the pressure restrictor will reduce the pressure introduced into the air spring 500, and at the same time, the vacuum introduced into the air spring 500 by the vacuum restrictor will also be reduced. If the throttling effect of the pressure throttler and the vacuum throttler is the same, the magnitude of the pressure introduced into the air cushion 500 by the pressure throttler is equal to that of the vacuum introduced into the air cushion 500 by the vacuum throttler, Fa is substantially equal to Fv, namely the difference between Fa and Fv is nearly zero, no extra force can push an object to the supporting surface, the thickness of the air cushion 500 is increased, and the oscillation fluctuation of the object is increased. If the throttling effect of the pressure restrictor is higher than that of the vacuum restrictor, the magnitude of the pressure restrictor introduced into the air cushion 500 is slightly smaller than that of the vacuum restrictor introduced into the air cushion 500, Fa is slightly smaller than Fv, i.e., the difference between Fa and Fv is represented as a force on an object to push the object to the supporting surface, which is greater than the weight of the object corresponding to the supporting area, so that the air cushion 500 returns to the equilibrium thickness.

Having elucidated the theoretical basis for using chokes of different throttling effects for the pressure outlet 110 and the pressure inlet 210 above, the difference between the dynamic characteristics of the air mattress 500 of the present invention and those of the PV-type air mattress 500 in the "high performance non-contact support platform" patent will be described below with reference to fig. 7, 8, 11, thereby further elucidating the role of the atmospheric communication channel 300 of the present invention.

The air mattress 500, as shown in figure 7 (which is a graph of the air mattress 500 of section a-a of the planar arrangement of the air mattress 500 of the present invention), is in a state of equilibrium, and the air mattress 500 holds and supports an object at a balanced air mattress 500 thickness, which is the best mode of operation of the present invention. The area occupied by Pa completely coincides with the area occupied by Pv, resulting in a balanced situation as shown in fig. 7 and 8. The air flow in the air cushion 500 is discharged or supplied with mass flow from the atmosphere communicating groove 300, each positive pressure unit 100/negative pressure unit 200 with the same size has the same positive pressure/negative pressure occupation area within a limited range, as shown in fig. 8, the problems of poor flatness of the supported object 400 and large variation of the thickness of the air cushion 500 caused by the difference of pressure distribution and pressure peak value caused by different positions of each basic unit are avoided, and the supported object 400 can keep stable and uniform thickness of the air cushion 500. The partial balance force and moment of each positive pressure unit 100/negative pressure unit 200 is equivalent to that of a large flat object subjected to bidirectional uniform load, so that the phenomenon that each basic unit generates inconsistent concentrated load, the whole borne object 400 is greatly deformed, and the whole borne object 400 is unstable and uneven in thickness of the air cushion 500 is avoided. As the air mattress 500 fluctuates and deflects downward, the pressure restrictor will introduce significantly more pressure into the air mattress 500, while the vacuum introduced into the air mattress 500 by the vacuum restrictor will only slightly increase, increasing both the pressure distribution and the vacuum pressure spikes within the air mattress 500. Although the pressure distribution of the positive pressure unit 100 and the negative pressure unit 200 is largely changed, the area occupied by Pa and the area occupied by Pv are identical at the same time of balance. The whole body is presented as a force for pulling the object away from the supporting surface, the force is far larger than the weight of the object corresponding to the supporting area, the object is forced to return to the thickness of the balance air cushion 500, and the safe distance between the object and the supporting surface is ensured. As the air mattress 500 fluctuates and deflects upward, the pressure restrictor will reduce the pressure introduced into the air mattress 500, while the vacuum introduced into the air mattress 500 by the vacuum restrictor is only slightly reduced, reducing both the pressure distribution and the vacuum pressure spikes within the air mattress 500. Although the pressure distribution of the positive pressure unit 100 and the negative pressure unit 200 is largely changed, the area occupied by Pa and the area occupied by Pv are identical at the same time of balance. The ensemble appears to push the object closer to the support surface with a force greater than the object weight corresponding to the support area, forcing the object back to the equilibrium air-cushion 500 thickness. No matter the positive pressure/negative pressure of the basic unit is increased/decreased or is in a balanced state, the air flow in the air cushion 500 is always discharged or supplied with mass flow from the atmosphere communicating groove 300, the pressure is always extended to the boundary of the communicating groove, namely, the local transition is the ambient pressure, and accordingly, the thin flexible supported object 400 is gradually transited from the flexibility far away/close to the supporting surface to the flexibility near/far away from the supporting surface in the position. More importantly, the area occupied by Pa/Pv does not change, and this property can make the thin flexible supported object 400 maintain three-dimensional wave-like fluctuation in the longitudinal direction and the transverse direction, and the wave wavelength of each wave of the positive pressure unit 100 and the negative pressure unit 200 is consistent, and the object is deformed into the shape as shown in FIG. 7. Compared with single-trend deflection deformation without fluctuation, the regular wavy fluctuation deformation can greatly increase the rigidity of the object, maintain the stability and the flatness of the object in the supporting and transporting processes and reduce the contact collision risk of the object with the supporting surface under the critical condition in the supporting and transporting processes.

When the air mattress 500 of fig. 11 (the behavior graph of the air mattress 500 of section C-C of the planar arrangement of the PV-type air mattress 500 in fig. 10) is in a balanced state, the air mattress 500 holds and supports an object at the thickness of the balanced air mattress 500, and the area occupied by Pa is similar to, but not completely identical to, the effective area occupied by PV, which becomes a balanced situation as shown in fig. 10 and 11. The mass flow provided by the pressure outlet 110 is partially evacuated inside the air bearing surface by the pressure inlet 210 connected to the vacuum source, and at the edge of the air bearing surface, the mass flow provided by the pressure outlet 110 is evacuated by the pressure inlet 210 connected to the vacuum source and the edge ambient outlet. The air cushion 500 generated in this arrangement has different pressure peaks and pressure distribution near the pressure peaks even though the pressure outlets 110 with the same structure and properties are located at different positions, as shown in fig. 12, because the central pressure is blocked, the pressure outlets 110 located at the boundary have larger space for air to flow, the peak of the positive pressure in the inner area of the air cushion 500 is larger than that in the edge area, and the peak of the negative pressure in the inner area of the air cushion 500 is smaller than that in the edge area due to the interaction between the positive pressure and the negative pressure. Even if the air bearing platform is provided with the vacuum pressure inlet 210 for discharging mass flow locally, the peak value of the pressure blockage in the high pressure area is only reduced, i.e. it is difficult to provide a completely uniform two-way rigid air cushion 500. As the air mattress 500 undulates and deflects downward, similar to fig. 7, both pressure and vacuum pressure spikes within the air mattress 500 increase. While the pressure distribution and peak value of the positive pressure unit '100' and the negative pressure unit '200' are greatly changed, the area occupied by Pa and the area occupied by Pv are also changed correspondingly: pa and hence Pv, appear as forces pulling the object away from the support surface. As the air cushion 500 undulates and deflects upward, similar to fig. 7, both the pressure and vacuum pressure distribution and spikes within the air cushion 500 decrease. While the pressure distribution and peak value of the positive pressure unit '100' and the negative pressure unit '200' are greatly changed, the area occupied by Pa and the area occupied by Pv are also changed correspondingly: pa slightly decreases and thus Pv slightly increases. The whole is presented as a force pushing the object closer to the support surface. No matter the positive pressure/negative pressure of the basic unit is increased/decreased or is in a balanced state, the areas occupied by the Pa and the Pv are difficult to keep consistent, the Pa/Pv distribution of each positive pressure unit '100'/negative pressure unit '200' is different according to positions, the stress condition cannot approach to uniform load, and deformation of a thin flexible object and non-uniformity of the thickness of the air cushion 500 are easily caused.

(6) Parameters affecting deformation of thin flexible objects

When the supported object 400 has large size, thin thickness and low rigidity, and high-precision flatness is required in the process, in addition to ensuring the inspection/processing of the object by the properties of the air cushion 500 of the present invention, the precision and stability of the object can be further improved by adjusting the following parameters: the whole bending rigidity of the object is improved, and the rigidity of the air cushion 500 is improved.

(1) Improving the whole bending rigidity of the object: compared with the single trend deflection deformation without fluctuation generated by a thin flat flexible object, the bending rigidity of the whole object can be improved by enabling the object to generate regular wavy fluctuation deformation as shown in figure 9. Meanwhile, the uniformity of the air cushion 500 is only true when the size of the base unit is much smaller than the object size. The positive pressure units 100 and the negative pressure units 200 are arranged in a substantially staggered manner, and the surface shape of the basic unit can be rectangular, circular, prismatic or other shapes. The more the number of the local three-dimensional wavy undulations generated by the same size of the supported object 400, the higher the rigidity of the object and the better the uniformity. One way to increase the local wave-like heave deformation is to increase the resolution of the basic unit, where "resolution" refers to the number of air bearing platforms, positive pressure units 100 and negative pressure units 200 of the same size. With the same size of the support surface 800, the smaller the basic unit size, the greater the number, the higher the resolution, the higher the rigidity of the object, the better the uniformity, and the less the deformation generated during the support and transport. On the air-floating platform, the resolution of the set basic units can be different according to the functions and positions of different areas. For example: in the object inspection/processing area requiring high precision, a high-resolution basic unit is arranged, and in order to reduce the manufacturing cost, low resolution is arranged in other areas; in the edge area of the air floating platform, high-resolution basic unit distribution is arranged to reduce the edge effect of the object. The edge effect means that the rigidity of generating deflection at the edge or corner of a thin flexible object is smaller than the rigidity of generating local deflection inside the object, namely the deflection of the edge of the object is far larger than the deflection inside the object under the same pressure distribution.

(2) Increasing the stiffness of the air mattress 500: by increasing the stiffness of the air mattress 500, the accuracy of the object during support and transport is increased. In the present invention, three direct parameters will affect the stiffness of the air mattress 500: increasing the gas supply pressure of the high pressure source; the throttling effect of the pressure throttling device is improved, for example, the throttling aperture can be reduced by small-hole throttling, the permeability coefficient can be reduced by porous throttling, and the like; a smaller balance cushion 500 thickness is selected to achieve a higher cushion 500 stiffness, but note that the relationship between the cushion 500 stiffness and the cushion 500 thickness is: the stiffness decreases as the thickness of the air mattress 500 increases when the air mattress 500 is thicker, and decreases as the thickness of the air mattress 500 decreases when the air mattress 500 is thinner. A flow field calculation design should be performed to maximize the stiffness of the air mattress 500 by taking an optimal balanced air mattress 500 thickness.

(7) Edge effect processing of objects

In the "high performance non-contact support platform" PV-type air-cushion 500, the supported object 400 loses uniformity and locality at the edges due to the effect of edge effects. Uniformity: because the rigidity of the edge of the object is far less than that of the local deformation of the interior, the edge deformation is greater than that of the interior deformation, and the large deformation of the structure influences the flow field, so that the pressure distribution of the basic unit at the edge of the object, the air cushion thickness and the interior unit have larger difference, namely the strong coupling effect of the structure and the flow field is shown. The flow field of the strong coupling effect causes the force generated by each basic unit of the edge supporting surface covered by the object to be different from the force generated by the internal basic unit, and due to the properties of pressure blockage and the like of the PV type air cushion, the basic units at the edge cannot be equivalently loaded uniformly in two directions, and the air cushion further loses the property of uniformity. At the same time, the uniformity of the air cushion is only true when the size of the basic cell needs to be much smaller than the size of the object. The locality is as follows: inside the object cover, the mass flow provided by the pressure outlet 110 is partially evacuated by a pressure inlet 210 connected to a vacuum source. At the edge of the object cover, the mass flow provided by the pressure outlet 110 is expelled by the 4 narrow rectangular borders around the support surface and the pressure inlet 210 connected to a vacuum source, so that the air cushion 500 loses its locality at the edge.

The air cushion 500 of the present invention only loses uniformity at the edges of the supported object 400 due to the influence of the edge effect. Uniformity: the strongly fluid-tightly coupled flow fields cause each base cell of the object-covered edge-bearing surface to generate a different force than the base cells of the interior, and the air cushion 500 loses its uniformity properties. The locality is as follows: the mass flow of the pressure outlet 110 and the mass flow of the pressure inlet 210 are both discharged and supplied through the atmosphere communication groove 300, regardless of the inside or the edge of the object cover, so that the air cushion 500 will maintain the local property even at the edge of the object cover.

To counteract the effects of edge effects of an object, the following three measures can be taken: a. improving the resolution of the basic unit of the edge area; b. the edge region is provided with a pressure partition, a pressure difference is formed in the high-pressure air cavity channel 600/the vacuum air cavity channel 700, and simultaneously, the pressure supplied to the inner region of the air floatation platform is larger than the pressure of the edge region, and similarly, the vacuum degree supplied to the inner region of the air floatation platform is larger than the vacuum degree of the edge region. The reason is that the rigidity of the edge of the object is far less than that of the local deformation in the inner part, and under the condition that the basic units of the edge and the basic units in the inner part have the same pressure distribution, the deformation of the edge is far greater than that of the inner part, so that the pressure distribution of the basic units with reduced edges leads the deformation of the edge of the object to be consistent with the local deformation in the inner part. The pressure zones can be arranged in various ways, for example, throttling structures are arranged in the air cavity channels to form the pressure difference between the edges and the inner air cavities, or the air cavity channels in the inner area and the air cavity channels in the edge area are separated to independently control the pressure of each area, and the like; c. only the positive pressure unit 100 is positioned at the edge of the air bearing platform to avoid objects from hitting the support surface 800 due to edge effects.

Meanwhile, the two measures of arranging the basic unit with high resolution in the local area and arranging the pressure subarea in the local area can be used as a compensation technology to adjust the problem of local unevenness of the carried object 400 caused by various reasons.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", "front", "rear", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that unless otherwise explicitly stated or limited, the terms "mounted," "connected," and "connected" are to be construed broadly and may include, for example, a fixed connection, a detachable connection, an integral connection, a mechanical connection, an electrical connection, a direct connection, an indirect connection via an intermediate medium, and a communication between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art. The embodiments and features of the embodiments of the present invention may be combined with each other without conflict. In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

The above-mentioned embodiments only express the embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. The precise air floating platform is characterized by comprising an air floating platform, wherein the air floating platform comprises one or more supporting surfaces (800) which are parallel to each other, and the supporting surfaces (800) comprise at least one positive pressure unit (100) and one negative pressure unit (200) which are arranged in a staggered mode; the positive pressure unit (100) comprises at least one pressure outlet (110), wherein the pressure outlet (110) provides pressurized gas and is used for generating a supporting gas film for supporting a supported object (400); the negative pressure unit (200) comprises at least one pressure inlet (210), the pressure inlet (210) providing a pressure value below ambient pressure, generating an adsorption pressure opposite to the supporting gas film;

an atmosphere communication groove (300) is formed around each positive pressure unit (100) and each negative pressure unit (200), and the atmosphere communication groove (300) partially discharges the mass flow of the pressure outlet (110) or partially provides the mass flow of the pressure inlet (210) so that the pressure at the atmosphere communication groove (300) is kept at the ambient pressure.

2. The precision air-bearing platform as claimed in claim 1, wherein the air-bearing platform is provided with vent holes (310) at intervals, one end of each vent hole (310) is communicated with the atmosphere communication groove (300), and the other end of each vent hole (310) is positioned outside the supporting surface (800) and is in fluid communication with ambient air pressure.

3. The precise air-floating platform as claimed in claim 1, wherein a high-pressure air cavity channel (600) is arranged in the air-floating platform, and each pressure outlet (110) is communicated with the high-pressure air cavity channel (600) through a pressure restrictor;

and a high-pressure source communicated with the high-pressure air cavity channel (600) is arranged on the outer side of the air floatation platform.

4. The precise air-floating platform according to claim 3, characterized in that a vacuum air cavity channel (700) is arranged in the air-floating platform, and each pressure inlet (210) is communicated with the vacuum air cavity channel (700) through an arranged vacuum restrictor;

a vacuum source communicated with the vacuum air cavity channel (700) is arranged on the outer side of the air floating platform; the throttling effect of the pressure throttling device is higher than that of the vacuum throttling device.

5. The precision air platform as claimed in claim 1, wherein a shallow vacuum groove (220) is provided on the support surface (800) at the pressure inlet (210).

6. The precision air-bearing platform according to any one of claims 1-5, characterized in that the support surface (800) comprises at least one central support surface and at least one edge support surface that are spliced to each other;

the local position of middle part supporting surface and/or edge supporting surface is provided with the pressure subregion, be provided with respectively in the pressure subregion malleation unit with the negative pressure unit.

7. The precision air-bearing platform as claimed in claim 6, wherein:

the resultant force of the positive pressure units in the pressure subareas is greater than that of the negative pressure units in the pressure subareas, and the resultant force of the positive pressure units and/or the negative pressure units in the pressure subareas is respectively less than or greater than that of the positive pressure units and the negative pressure units outside the pressure subareas.

8. The precision air-floating platform according to claim 6, characterized in that the resolution of the positive pressure unit (100) and/or the negative pressure unit (200) inside the pressure section is smaller or larger than the resolution of the positive pressure unit (100) and/or the negative pressure unit (200) outside the pressure section, respectively.

9. The precision air-floating platform as claimed in claim 6, wherein said pressure zones comprise a plurality of said positive pressure units or said negative pressure units.

10. The precision air-floating platform according to claim 1, characterized in that the resultant force of the positive pressure unit (100) and/or the resultant force of the negative pressure unit (200) is 5-80 times of the gravity value of the corresponding area of the supported object (400).