Combining Elementary Siphons of Petri Nets and Heuristic Algorithm for Controller Design of Deadlock Prevention for Flexible Manufacturing Systems

• Main Authors: Hong-Jie Zeng, 曾泓傑
• Other Authors: Ming-Shan Lu
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/22231858117054291569

碩士 === 國立雲林科技大學 === 工業工程與管理系 === 103 === A flexible manufacturing system (FMS) refers to an automatic manufacturing system in which some amount of flexibility allows the system to react in case of changes, whether predicted or unpredicted. It features high flexibility and high production efficiency. During operation, the most common problem encountered is the deadlock as a result of products having to share some common resources, causing the system to stop and resulting in serious loss. The current study, therefore, aimed to use the Petri net model to develop a FMS, specifically focusing on the use of Siphon Control Theory to locate Elementary Siphons that cause deadlocks in the Petri net model. Deadlock avoidance could be achieved by the addition of controllers using the connection position of the controller arc (Ezpeleta et al., 1995) and by the removal of places repeatedly controlled by controllers (Liu, 2014). However, the connection position of the controller arc affected the reachable states of the Petri net model and the reachable states could be improved by removing the flow places controlled by controllers. Therefore, a heuristic search together with Excel VBA was adopted to develop a program to automatically search for the best connection position of the controller arc, in an attempt to contruct the Petri net model with deadlock avoidance and more reachable states, making the system have higher flexibility.