平面顯示器玻璃基板主動式氣浮平台之設計與控制研究

Abstract

本研究旨在發展具主動控制之平面顯示器玻璃基板氣浮平台系統，將高壓氣體輸入至氣浮塊內，藉由氣浮塊表面之細小孔隙噴出高壓氣體，利用此高壓氣體在氣浮塊與其上之玻璃基板間形成氣墊層，利用氣墊層與外界大氣壓之壓差，藉以提供玻璃基板的升力，使玻璃基板可漂浮於氣浮平台之上，不會直接與平台接觸，減少玻璃基板與平台間磨擦力。此氣浮平台將可運用於TFT-LCD玻璃基板與太陽能面板的工業製程中，改良傳統工業製程中，利用滾輪支撐與帶動的運送方式，以減少玻璃基板因為摩擦力存在而毀損的機會。 本文針對時變氣壓系統的數學模型，進行降階簡化，使氣壓系統為一三階非線性時變系統，且能滿足匹配條件。在控制器設計的部分，引用具 性能追蹤之函數近似法為基礎之適應滑動控制器，採用函數近似法近似非線性系統之數學模型，藉以克服系統之高度不確定性及時變問題，本文採用軌跡-定位的方式進行定位控制，以求同時兼顧系統之暫態及穩態特性。 本文首先以電腦進行靜態之玻璃基板於氣浮平台上之變形量模擬，並在實際實驗前利用電腦進行動態的模擬，藉以驗證其控制系統架構之可行性，最終以實驗的方式來實現，其實驗的項目包含玻璃基板漂浮高度之位移量軌跡追蹤控制，穩態穩定性之分析及系統之強健性分析。

The objective of this thesis is to develop an air bearing table with active control for the floating altitude of the glass substrates of TFT-LCD or solar energy. The principle of an air bearing table is to input the high pressure air to the air bearing blocks on which there are small orifices to spurt the high pressure air such as to form an air cushion between the air bearing and the glass. The lifting force to the glass can be formed by using the difference in pressure between the air cushion and the atmospheric pressure such that the glass substrates can float on the air bearing table and don’t contact the air bearing table directly. Hence, it can reduce the friction between the glass substrates and the air bearing table in compared with the conventional roller conveyors. The study first derives the nonlinear time-variant mathematical models of pneumatic system and then simplify the models for a 3rd system. In the controller design, Fourier series-based adaptive sliding-mode controller with tracking performance is used. To ease the adverse effects caused by approximate errors, unmodeled dynamics and disturbances prior to constructing the control input , the tracking design technique and the Fourier series-based functional approximation technique are incorporated into the sliding-mode control method. Bedsides, this study also analyze the deformation of the glass substrates on the different arranged air bearing table in the steady state for ensuring better air bearing effects and less deformation of glass substrates. Then, the dynamic simulation of overall air-bearing table is implemented for confirming the feasibility of the developed systems. Finally, practical experiments, including position step response, path tracking control of the floating altitude of the glass substrates are perfromed for the verifying the control performance, stability and robustness of the developed system.