Zero-stiffness vibration isolator for double-layered aerostatic orthogonal decoupling and sliding knuckle bearing angular decoupling

Abstract

A zero-stiffness vibration isolator for double-layered aerostatic orthogonal decoupling and sliding knuckle bearing angular decoupling belongs to the technical field of precision vibration isolation. A sleeve and an aerostatic plate of a vibration isolator body are lubricated and supported by an aerostatic surface in between, the aerostatic plate and a lower mounting plate of the vibration isolator body are lubricated and supported by an aerostatic surface in between, a piston barrel and the sleeve of the vibration isolator body are lubricated and supported by an aerostatic surface in between, the degree of freedom of horizontal linear motion between the upper mounting plate and the lower mounting plate is decoupled by two layers of orthogonal aerostatic slideways, the degree of freedom of angular motion between the upper mounting plate and the lower mounting plate is decoupled by a sliding knuckle bearing, and voice coil motors, displacement sensors, limit switches, a controller and a driver are formed into a closed-loop feedback position control system, which can accurately control the relative position between the upper mounting plate and the lower mounting plate. The zero-stiffness vibration isolator has the characteristics of three-dimensional zero stiffness, high positioning precision and decoupling of the degree of freedom of linear motion and the degree of freedom of angular motion, and can effectively solve the problem of high-performance vibration isolation in ultra-precision measuring instruments and machining equipment, particularly in step scanning lithographic machines.

Description

technical field [0001] The invention belongs to the technical field of precision vibration isolation, and mainly relates to a zero-stiffness vibration isolator for double-layer air bearing orthogonal decoupling and sliding joint 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 width...

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 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 decoupling, the friction between the decoupling mechanism components of the angular motion freedom introduces additional stiffness, which restricts the vibration isolation performance

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

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