創新氣浮平台氣隙自調機構之研發

Abstract

本文運用氣靜壓氣體軸承的工作原理，設計出一種具一維方向平面精度保持功能的自調機構。本文嘗試透過比例式調壓閥及接觸式線性光學尺(LVDT)做即時距離檢測的方式，對氣體軸承的進氣壓力進行調控進而改變其氣隙高度，而達到前述平面精度保持與修正的自調功能。本研究經由氣體軸承的相關理論與靜平衡計算設計出機構模型，並利用高階機構動態模擬分析軟體ADAMS的模擬，以分析本自調機構受氣浮力時的動態特性。由理論推導及實驗結果證明，經由進氣壓力的控制以調節氣體軸承氣隙高度進而達成平面精度保持和修正的目的為可行的做法，其可達之平面自調精度為1μm，系統控制響應則為400ms。 期望藉由此一自調機構的研究，對於精密機械和量測設備在誤差補償及量測的處理上，提出一種新的設計，即不需要複雜的機構配置及控制系統架構亦能達到相對平面精度保持和修正的目的。而氣體軸承的計算與分析過程，則可做為後續類似的氣靜壓止推軸承設計或評估時的參考。

The objective of the thesis is to design an air gap self-adjusting mechanism by applying hydrostatic type air bearing theory and force function. The thesis proposes an integration control unit including the proportional pressure valve and linear optical scale sensor (LVDT) as real time air gap height detector and compensator respectively. This gap height pneumatic control unit can control the air bearing inlet pressure for maintaining the defined air gap height to afford required plane levelness. The experimental model of air gap self -adjusting mechanism of the air gap floating stage has also been designed based on the hydrostatic theory and dynamic characteristics analysis using ADAMS. The investigation results derived both from theoretical and experimental process show that, 1μm levelness accuracy and 400ms system signal response time can be achieved by using the air bearing inlet pressure control technology to keep it in the required status of air gap height. The proposed innovative self-adjusting mechanism demonstrates a new alternative approach of error compensation method for the application of new designed precision machinery and measuring equipment without the requirement of complex configuration and control system architecture. The pressure and control model of the proposed air bearing can be a reference in the similar application such as thrust hydrostatic bearing design.