Showing 3 results for Petri Net
A. Doostparast Torshizi, S.r. Hejazi,
Volume 21, Issue 2 (5-2010)
Abstract
In highly competitive industrial market, the concept of failure analysis is an unavoidable fact in complex industrial systems. Reliability of such systems not only depends on the reliability of each element of these systems, but also depends on occurrence of sequence of failures. In this paper, a novel approach to sequential failure analysis is proposed which is based upon fuzzy logic and the concept of Petri nets which is utilized to track all the risky behaviors of the system and to determine the potential failure sequences and then prioritizing them in order to perform corrective actions. The process of prioritizing failure sequences in this paper is done by a novel similarity measure between generalized fuzzy numbers. The proposed methodology is demonstrated with an example of two automated machine tools and two input/output buffer stocks.
Meysam Zareiee, Abbas Dideban, Ali A. Orouji ,
Volume 22, Issue 2 (6-2011)
Abstract
Discrete event system, Supervisory control, Petri Net, Constraint |
This paper presents a method to manage the time in a manufacturing system for obtaining an optimized model. The system in this paper is modeled by the timed Petri net and the optimization is performed based on the structural properties of Petri nets. In a system there are some states which are called forbidden states and the system must be avoided from entering them. In Petri nets, this avoidance can be performed by using control places. But in a timed Petri net, using control places may lead to decreasing the speed of systems. This problem will be shown on a manufacturing system. So, a method will be proposed for increasing the speed of the system without using control places .
Abbas Dideban, Maysam Zareiee, Ali A. Orouji, Hassan Rezaei Soleymanpour ,
Volume 24, Issue 1 (2-2013)
Abstract
This paper deals with the problem of forbidden states in discrete event systems modeled by Petri Net. To avoid the forbidden states, some constraints which are called Generalized Mutual Exclusion Constraints can be assigned to them. Enforcing these constraints on the system can be performed using control places. However, when the number of these constraints is large, a large number of control places must be connected to the system which complicates the model of controller. In this paper, the objective is to propose a general method for reducing the number of the mentioned constraints and consequently the number of control places. This method is based on mixing some constraints for obtaining a constraint verifying all of them which is performed using the optimization algorithms. The obtained controller after reducing the number of the control places is maximally permissive.
