Design and Control of an Active Air Bearing Table for Flat Panel Display Glass Subtrate
Date Issued
2009
Date
2009
Author(s)
Chen, Keng-Ku
Abstract
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. he 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. edsides, 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.
Subjects
glass substrate
TFT-LCD
air-bearing system
pneumatic servo system
adaptive sliding mode controller
function approximation
H-infinite control
Type
thesis
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