Zero-stiffness vibration isolator and vibration isolation system for angular decoupling of rolling joint bearings

Abstract

The invention belongs to the technical field of precision vibration isolation, and relates to a zero-stiffness vibration isolator with a rolling oscillating bearing angle degree decoupling function and a vibration isolation system. A sleeve of a vibration isolator body and a lower mounting plate as well as a piston barrel and the sleeve are lubricated and supported through air floatation surfaces respectively, degree of freedom of angular motion between an upper mounting plate and the lower mounting plate is decoupled by a rolling oscillating bearing, and voice coil motors, displacement sensors, limit switches, a controller and a drive form a closed position loop feedback control system which is used for precision control of relative position of the upper mounting plate and the lower mounting plate. The zero-stiffness vibration isolator has the advantages of zero three-dimension stiffness, high positioning precision and angle degree decoupling and can obtain extremely-low-intrinsic-frequency and outstanding low-frequency / ultralow frequency vibration isolation performances, and accordingly high-performance vibration isolation of ultraprecise measuring instruments, machining equipment and particularly step-scan lithography machines is achieved.

Description

technical field [0001] The invention belongs to the technical field of precision vibration isolation, and mainly relates to a zero-stiffness vibration isolator and a vibration isolation system for angular decoupling of rolling joint bearings. 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 of the step...

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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