<p>High precision magnetic levitation control
methodologies during the manufacture of Organic light-emitting diode (OLED)
displays are designed, manipulated, and experimentally validated in this
thesis. OLED displays have many advantages over conventional display
technologies including thinner, lighter, lower power consumption, higher
resolutions, and greater brightness. However, OLED displays require tighter
environmental conditions of the manufacturing processes without the
introduction of vibration and contamination. For this reason, magnetic
levitation is used to transport the displays attached on the carrier during the
manufacturing process. This thesis addresses several critical problems related
to implement the levitation control performance of the carrier's motion during
the manufacturing process. </p>
<p>Attractive magnetic levitation requires
measurement of the airgap between the carrier and the levitation
electromagnets. An algorithm for modeling the gap sensor installation errors
was developed and subsequently used for controller development. A levitation
controller only was initiated as the stationary point for optimal state
feedback controller-observer compensator developed in this study. This optimal state
feedback controller-observer compensator allows the carrier to be passed from
support fixtures without the introduction of vibration. This controller was
designed, and its levitation control performance confirmed with both simulation
and experimental validation. To implement the levitation control performance of
the carrier's motion, a second order notch filter and a first order low pass
filter are designed to minimize the mechanical resonance and noise from the gap
sensor, respectively. To reduce the sudden change of the levitation forces
owing to the discrete allocation of the levitation electromagnets, a section
control algorithm is developed; the sum of the levitation forces is equal to
the weight of the carrier and the sum of the moment along the propulsion axis
is equal to zero. </p>
<p>Using the developed control strategies, the peak
to peak variation of the carrier’s motion at a standstill was 50 µm. This same
motion at low-speed 30 mm/s was 250 µm. While at high speed 300 mm/s was 430 µm.
The relative improvement in the levitation control performance of optimal state
feedback controller-observer compensator over the levitation controller only
was a peak to peak attenuation of 50 µm at low-speed and 270 µm at high-speed.
Most significantly while using optimal state feedback controller-observer compensator
could be passed from support fixture to support fixture, i.e., through the deadzone,
without mechanical contact or other manufacturing processes, inhibiting
vibration. </p>
<p>Having
comparative simulation and experimental validation, the proposed control
strategies were validated to improve the levitation control performance of the
carrier under uncertain disturbance and sensor installation error, and it is
expected to manufacture OLED displays with high productivity and low defect
rate.</p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/7859873 |
| Date | 15 May 2019 |
| Creators | Jaeyoung Kim (6442592) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/A_Study_on_a_High_Precision_Magnetic_Levitation_Transport_System_for_Carrying_Organic_Light-Emitting_Diode_Displays/7859873 |
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