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Mathematical Problems in Engineering
Volume 2015, Article ID 537893, 19 pages
http://dx.doi.org/10.1155/2015/537893
Research Article

Comparison and Evaluation of Deadlock Prevention Methods for Different Size Automated Manufacturing Systems

1Industrial Engineering Department, College of Engineering, King Saud University, Riyadh 11421, Saudi Arabia
2Mechanical Engineering Department, Helwan University, Cairo 11792, Egypt

Received 13 January 2015; Revised 26 June 2015; Accepted 3 August 2015

Academic Editor: Yan-Jun Liu

Copyright © 2015 Emad Abouel Nasr et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

In automated manufacturing systems (AMSs), deadlocks problems can arise due to limited shared resources. Petri nets are an effective tool to prevent deadlocks in AMSs. In this paper, a simulation based on existing deadlock prevention policies and different Petri net models are considered to explore whether a permissive liveness-enforcing Petri net supervisor can provide better time performance. The work of simulation is implemented as follows. (1) Assign the time to the controlled Petri net models, which leads to timed Petri nets. (2) Build the Petri net model using MATLAB software. (3) Run and simulate the model, and simulation results are analyzed to determine which existing policies are suitable for different systems. Siphons and iterative methods are used for deadlocks prevention. Finally, the computational results show that the selected deadlock policies may not imply high resource utilization and plant productivity, which have been shown theoretically in previous publications. However, for all selected AMSs, the iterative methods always lead to structurally and computationally complex liveness-enforcing net supervisors compared to the siphons methods. Moreover, they can provide better behavioral permissiveness than siphons methods for small systems. For large systems, a strict minimal siphon method leads to better behavioral permissiveness than the other methods.