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Design of Optimal Petri Net Supervisors for Flexible Manufacturing Systems via Weighted Inhibitor Arcs |
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| Authors: | XuYa Cong Chao Gu Murat Uzam YuFeng Chen Abdulrahman M Al‐Ahmari NaiQi Wu MengChu Zhou ZhiWu Li |
| Affiliation: | 1. School of Electro‐Mechanical Engineering, Xidian University, Xi'an, China;2. Key Laboratory of Electronic Equipment Structure Design (Xidian University), Ministry of Education, Xi'an, China;3. Elektrik‐Elekronik Mühendisli?i B?lümü, Meliksah Universitesi Muhendislik‐Mimarlik Fakultesi, Kayseri, Turkey;4. Institute of Systems Engineering, Macau University of Science and Technology, Taipa, Macau;5. FARCAMT Chair, Advanced Manufacturing Institute, King Saud University, Riyadh, Saudi Arabia;6. College of Engineering, Industrial Engineering Department, King Saud University, Riyadh, Saudi Arabia;7. Department of Electrical and Computer Engineering, New Jersey Institute of Technology, Newark, USA;8. Renewable Energy Research Group, King Abdulaziz University, Jeddah, Saudi Arabia |
| Abstract: | This paper develops an approach to the design of an optimal Petri net supervisor that enforces liveness to flexible manufacturing systems. The supervisor contains a set of observer places with weighted inhibitor arcs. An observer place with a weighted inhibitor arc is used to forbid a net from yielding an illegal marking by inhibiting the firing of a transition at a marking while ensuring that all legal markings are preserved. A marking reduction technique is presented to decrease the number of considered markings, which can dramatically lower the computational burden of the proposed approach. An integer linear program is presented to simplify the supervisory structure by minimizing the number of observer places. Finally, several examples are used to shed light on the proposed approach which can lead to an optimal supervisor for the net models that cannot be optimally controlled via pure Petri net supervisors. |
| Keywords: | Deadlock prevention flexible manufacturing system observer place Petri net supervisory control weighted inhibitor arc |