A deadlock prevention approach for flexible manufacturing systems with uncontrollable transitions in their Petri net models

Abstract

Deadlocks are a highly undesired situation in a fully automated flexible manufacturing system, whose occurrences are tied to the existence of shared resources that are competed by different production processes. In the last two decades, a fair amount of research has been done on deadlock analysis and control for flexible manufacturing systems, leading to a variety of strategies in the literature. Petri nets are a promising mathematical tool to handle deadlock problems in flexible manufacturing systems. However, most deadlock control policies based on a Petri net formalism assume that all the transitions in a plant model are controllable. However, uncontrollability of events are a natural feature in a real-world production system. This paper proposes a deadlock prevention policy for a class of Petri nets by considering the existence of uncontrollable transitions. Deadlocks are prevented by adding monitors to a plant Petri net model, whose addition does not inhibit the firings of uncontrollable transitions. Linear programming techniques are employed to find transitions to which a monitor points in order that a more permissive liveness-enforcing Petri net supervisor can be found. A number of manufacturing examples are used to demonstrate the proposed methods.

Confusion Diagnosis and Control of Discrete Event Systems Using Synchronized Petri Nets

“…In this case, there is a deadlock state. The work on deadlock resolution is extensively discussed in [5,18,22,27,28,29,30,32,33]. We can use deadlock prevention or recovery strategies to control it and the control processes do not affect the control of confusions.…”

New Controllability Condition for Siphons in Ws3PR Nets

“…Petri nets are well suited to describing the behavioral characteristics of FMS, such as liveness, boundedness, concurrency and conflict. Therefore, they are widely used to model FMS and deal with deadlock problems [3][4][5][6][7][8][9]. There are many subclasses of Petri nets.…”

Comment on “A Deadlock Prevention Approach for Flexible Manufacturing Systems with Uncontrollable Transitions in Their Petri Net Models”

“…A deadlock prevention approach for flexible manufacturing systems (FMS) with uncontrollable transitions in their Petri net models (PNM) was proposed in . A few examples were considered to show the applicability of the proposed approach.…”

“…Fig. depicts the PNM of an FMS considered in . This is a well‐known FMS example widely used in the Petri‐net based deadlock prevention literature to demonstrate a variety of design methods of liveness‐enforcing supervisors .…”

“…This is a well‐known FMS example widely used in the Petri‐net based deadlock prevention literature to demonstrate a variety of design methods of liveness‐enforcing supervisors . In the literature, generally all the transitions of this PNM are assumed to be controllable, but in it is assumed that transitions t1, t2, t7, t11, t15, and t16 are controllable and other transitions are uncontrollable. The PNM shown in Fig.…”