Q($\lambda$) learning based route guidance of overhead hoist transport vehicle in automated material handling system = 자동 반송 시스템에서의 Q($\lambda$) 학습 기반 OHT 차량 경로 설정

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Overhead Hoist Transport (OHT) vehicle is widely used in the automated material handling system (AMHS) of semiconductor wafer fabrication facilities (FAB). Hundreds of OHTs deliver wafer lots on complex tracks, efficient operation of the OHT is one of the key factors of the overall performance of the modern semiconductor FAB. Commonly used routing methods include static Dynamic Programming (DP) approach, periodically updated DP approach, and online DP approach. However, routing based on the existing optimization approach can not effectively respond unexpected events such as delay time due to the OHT loading / unloading or congestion in the track. In this paper, we propose a routing algorithm based on Q ($\lambda$) learning in order to operate the automated transport system efficiently, which avoids congestion and can be applied to actual field. It gathers real-time routing information and measures the expected transport time for each alternative route. The learning-based algorithm is used to determine the next position of the OHT while avoiding congestion in the track. We also verify the performance of the algorithm through simulation experiments. Compared with the practical routing approach, the proposed method showed better performance in terms of the median of average lots delivery time. This study is conducted with one of the biggest global AMHS providers in the semiconductor industries.
Advisors
Jang, Young Jaeresearcher장영재researcher
Description
한국과학기술원 :산업및시스템공학과,
Publisher
한국과학기술원
Issue Date
2017
Identifier
325007
Language
eng
Description

학위논문(석사) - 한국과학기술원 : 산업및시스템공학과, 2017.8,[iv, 30 p. :]

Keywords

Automated Material Handling System▼aRouting▼aOverhead Hoist Transport▼aQ learning▼aPractical Approach; 자동 반송 시스템▼a경로 설정▼aOverhead Hoist Transport▼a큐러닝▼a현업 방식

URI
http://hdl.handle.net/10203/243044
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=718605&flag=dissertation
Appears in Collection
IE-Theses_Master(석사논문)
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