Coplane air floatation orthogonal decoupling and air floatation ball bearing angle decoupling magnetic levitation vibration isolator

Abstract

A coplane air floatation orthogonal decoupling and air floatation ball bearing angle decoupling magnetic levitation vibration isolator belongs to the technical field of precision vibration isolation. Lubrication and supporting between a sleeve of a vibration isolator main body and a lower installation plate and between a piston cylinder and the sleeve are carried out through a magnetic levitation thrust bearing and a static pressure air floatation face respectively, freedom of horizontal rectilinear motion between an upper installation plate and the lower installation plate is decoupled through a coplane orthogonal air floatation guide rail, freedom of angular motion between the upper installation plate and the lower installation plate is decoupled through an air floatation ball bearing, a position closed loop feedback control system is formed by a voice coil motor, a displacement sensor, a limit switch, a controller and a driver, and relative locations of the upper installation plate and the lower installation plate are accurately controlled. The vibration isolator has characteristics of zero three-dimensional stiffness, high positional accuracy and rectilinear motion freedom and angular motion freedom decoupling, and can effectively solve high-performance vibration isolation problems of ultra-precise measurement device and processing equipment, in particular to a step scanning photoetching machine.

Description

technical field [0001] The invention belongs to the technical field of precision vibration isolation, and mainly relates to a magnetic suspension vibration isolator for coplanar air bearing orthogonal decoupling and air bearing ball bearing angle decoupling. Background technique [0002] 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 w...

AI Technical Summary

Problems solved by technology

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-film resonance, and poor stability

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 angular motion freedom of rotation 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 the upper and lower mounting plates with angular freedom of rotation around the horizontal axis, but due to the high angular stiffness of the rubber blocks, the angular freedom of motion cannot be effectively achieved High degree of decoupling, there is friction between the parts of the decoupling mechanism and a large additional stiffness is introduced, which restricts the natural frequency and low frequency vibration isolation performance

However, the proposed technical solution still does not effectively solve the problem of precise positioning of the vibration isolator and decoupling of the angular motion degrees of freedom of the upper and lower mounting plates.

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