碩士 / 國立臺灣科技大學 / 電機工程系 / 105 / Automated guided vehicles (AGVs) are popularly used in material handling systems of automated factories. The operation of an AGV can be categorized as the guidance with rail tracks or optical/ magnetic tracks and the guidance with autonomous navigation. The AGV had to follow the deployed tracks for the guidance with rail tracks or optical/ magnetic tracks. Although such a system exhibits high reliability and simple control schemes, limited track combination is the drawback. Contrarily, autonomous navigation approaches did not need any deployed tracks; however, they employed advanced localization and obstacle detection sensor for navigation. Therefore, autonomous navigation approaches provided high trajectory flexibility; nevertheless, complicated system architecture and reliability would be practical concerns. To combine the advantages of two aforementioned movement systems, this study proposes a cyber-physical track (CPT) AGV system that used optical guidance tracks and regional autonomous tracks as well. The CPT AGV system is composed of the CPT design, path planning and control system. The physical track system is formed by a number of visible track segments with a specific color. Bar code plates were placed beside the track to identify specific locations such as loading/ unloading buffers and cyber and physical track junctions (CPTJs). Cyber tracks were freely formed between any of two distinct CPTJs without a physical track connection, and the regional autonomous navigation was applied accordingly. Hence, cyber represents an invisible short-cut track in a track system. The path planning was realized with A* algorithm that is capable to find an optimal path from CPT segments to deal with a "from-to" movement command. To facilitate the CPT operation, a low cost line scanner camera was used to detect the color track and the identification shown on a bar code plate; seven sonar sensors were used to detect obstacles surrounding the robot; two incremental wheel encoders were desired to obtain the odometry. In addition to sensor modules, a controller was implemented for path planning and fuzzy logic based reactive navigation. Finally, a CPT system containing six loading/ unloading buffers and 4 CPTJs was produced for discussion, and the experimental results were used to evaluate the feasibility of CPT AGV systems.
| Identifer | oai:union.ndltd.org:TW/105NTUS5442003 |
| Date | January 2016 |
| Creators | Yu-Siang Wang, 王昱翔 |
| Contributors | Chung-Hsien Kuo, 郭重顯 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 78 |
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