Erratum to Deadlock Prevention Based on Structure Reuse of Petri Net Supervisors for Flexible Manufacturing Systems [Jan 12 178-191]

2013 ◽  
Vol 43 (2) ◽  
pp. 474-474
Author(s):  
Z. W. Li ◽  
G. Y. Liu ◽  
H. M. Michael ◽  
M. C. Zhou
Keyword(s):  
Petri Net ◽  
Flexible Manufacturing ◽  
Flexible Manufacturing Systems ◽  
Manufacturing Systems ◽  
Deadlock Prevention

Design of Optimized Petri Net Supervisors for Flexible Manufacture Systems Based on Elementary Siphons

2013 ◽  
pp. 322-342
Author(s):  
Mingming Yan
Keyword(s):  
Petri Net ◽  
Flexible Manufacturing ◽  
Flexible Manufacturing Systems ◽  
Manufacturing Systems ◽  
Deadlock Prevention ◽  
Excellent Performance ◽  
Plant Model ◽  
Elementary Siphon ◽  
Flexible Manufacture ◽  
Major Target

This chapter focuses on the deadlock prevention problems in Flexible Manufacturing Systems (FMS), and the major target is to design more excellent controllers that lead to a more permissive supervisor by adding a smaller number of monitors and arcs than the existing ones in the literature for the design of liveness-enforcing Petri net supervisors. The authors distinguish siphons in a Petri net model by elementary and dependent ones. For each elementary siphon, a monitor is added to the plant model such that it is invariant-controlled without generating emptiable control-induced siphons, and the controllability of a dependent siphon is ensured by changing the control depth variables of its related elementary siphons. Hence, a structurally simple Petri net supervisor is achieved. Based on the previous work, this chapter explores two optimized deadlock prevention approaches based on elementary siphons that can achieve the same control purpose and have more excellent performance.

Petri Net Based Deadlock Prevention Approach for Flexible Manufacturing Systems

2011 ◽  
pp. 416-433 ◽  
Author(s):  
Chunfu Zhong ◽  
Zhiwu Li
Keyword(s):  
Petri Nets ◽  
Petri Net ◽  
Flexible Manufacturing ◽  
Mixed Integer Linear Programming ◽  
Flexible Manufacturing Systems ◽  
Manufacturing Systems ◽  
Iteration Step ◽  
Mixed Integer ◽  
Deadlock Prevention ◽  
Prevention Approach

In flexible manufacturing systems, deadlocks usually occur due to the limited resources. To cope with deadlock problems, Petri nets are widely used to model these systems. This chapter focuses on deadlock prevention for flexible manufacturing systems that are modeled with S4R nets, a subclass of generalized Petri nets. The analysis of S4R leads us to derive an iterative deadlock prevention approach. At each iteration step, a non-max-controlled siphon is derived by solving a mixed integer linear programming. A monitor is constructed for the siphon such that it is max-controlled. Finally, a liveness-enforcing Petri net supervisor can be derived without enumerating all the strict minimal siphons.

Petri Net Channelized-Based Deadlock Prevention Policy for Flexible Manufacturing Systems

2011 ◽  
Vol 317-319 ◽  
pp. 552-555
Author(s):  
Yi Sheng Huang ◽  
Ter Chan Row
Keyword(s):  
Control System ◽  
Petri Net ◽  
Flexible Manufacturing ◽  
Flexible Manufacturing Systems ◽  
Manufacturing Systems ◽  
Control Policy ◽  
Original Model ◽  
Deadlock Prevention ◽  
Prevention Policy ◽  
Maximal Permissiveness

Petri nets are employed to model flexible manufacturing systems (FMSs). However, the system deadlocked are possible happened. The conventional deadlock prevention policies are always to forbid the system entering the deadlock by using the control places. To obtain a live system, some dead markings must be sacrificed in the traditional policies. Therefore, the original reachability states of the original model can not be conserved. However, this paper is able to maintain all the reachability states of the original net and guaranty the control system live. Under our control policy, all number of reachability states of the original net will be preserved. Finally, two examples are performed that can reach the maximal permissiveness for FMSs using Petri net models (PNMs).

A Channelized Deadlock Prevention Policy for Flexible Manufacturing Systems Using Petri Net Models

2011 ◽  
Vol 284-286 ◽  
pp. 1498-1501
Author(s):  
Yi Sheng Huang ◽  
Ter Chan Row
Keyword(s):  
Petri Net ◽  
Flexible Manufacturing ◽  
Flexible Manufacturing Systems ◽  
Manufacturing Systems ◽  
Control Policy ◽  
Deadlock Avoidance ◽  
Deadlock Prevention ◽  
Deadlock Detection ◽  
Prevention Policy ◽  
Maximal Permissiveness

Deadlock prevention, deadlock detection and deadlock avoidance strategies are used to solve the deadlock problems of flexible manufacturing systems (FMSs). The conventional prevention policies were always attempt to prevent the system entering the deadlocked situation by using a few control places. On can know that one prohibits the deadlocked markings, some dead markings will be sacrificed. Therefore, the reachability states will become less than the initial net. However, our goal is to preserve all the reachability states of the initial net. Under our control policy, the deadlocks or deadlock zone will be channelized to live markings such that all the dead markings in reachability states will be conserved. Finally, an example is performed and can obtain the maximal permissiveness of a Petri net model. The other examples are all getting the same result. To our knowledge, this is the first work that employs the channelized method to prevent the deadlock problem for FMSs.

Deadlock Prevention for Automated Manufacturing Systems with Uncontrollable and Unobservable Transitions

2013 ◽  
pp. 367-387
Author(s):  
Meng Qin
Keyword(s):  
Petri Nets ◽  
Petri Net ◽  
Flexible Manufacturing ◽  
Flexible Manufacturing Systems ◽  
Manufacturing Systems ◽  
Deadlock Prevention ◽  
Sufficient Condition ◽  
Prevention Policy ◽  
Automated Manufacturing Systems ◽  
Partial Observability

Many deadlock prevention policies on the basis of Petri nets dealing with deadlock problems in flexible manufacturing systems exist. However, most of them do not consider uncontrollable and unobservable transitions. This chapter solves deadlock problems in Petri nets with uncontrollable and unobservable transitions. A sufficient condition is developed to decide whether an existing deadlock prevention policy is still applicable in a Petri net with uncontrollable and unobservable transitions, when the policy itself is developed under the assumption that all the transitions are controllable and observable. Moreover, the author develops a deadlock prevention policy to design liveness-enforcing supervisors for a class of Petri nets with partial observability and controllability of transitions. Furthermore, a sufficient condition to decide the existence of a monitor to enforce a liveness constraint is developed.

A Computationally Improved Control Policy for FMS Using Crucial Marking/Transition-Separation Instances

2013 ◽  
pp. 61-82
Author(s):  
Yi-Sheng Huang ◽  
Yen-Liang Pan
Keyword(s):  
Petri Net ◽  
Flexible Manufacturing ◽  
Flexible Manufacturing Systems ◽  
Manufacturing Systems ◽  
Control Policy ◽  
Deadlock Avoidance ◽  
Deadlock Prevention ◽  
Deadlock Detection ◽  
Optimal Controllers ◽  
Unique Method

Deadlock prevention, deadlock detection, and deadlock avoidance strategies are used to solve the deadlock problems of Flexible Manufacturing Systems (FMS). The theory of regions has been recognized as the unique method for obtaining maximally permissive controllers in the existing literature. All legal and live maximal behavior of a Petri net model can be preserved by using a Marking/Transition-Separation Instance (MTSI). However, obtaining all sets of MTSIs is an extremely time consuming problem. This work proposes Crucial Marking/Transition-Separation Instances (CMTSIs) that allow designers to employ few MTSIs to deal with deadlocks. The advantage of the proposed policy is that a maximally permissive controller can be obtained with drastically reduced computation. Experimental results, by varying the markings of given net structures, indicate that it is the most efficient policy to obtain optimal controllers among existing methods based on the theory of regions.

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