Global Supervisory Structure for Decentralized Systems of Flexible Manufacturing Systems Using Petri Nets

Abstract

Decentralized supervisory structure has drawn much attention in recent years to address the computational complexity in designing supervisory structures for large Petri net model. Many studies are reported in the paradigm of automata while few can be found in the Petri net paradigm. The decentralized supervisory structure can address the computational complexity, but it adds the structural complexity of supervisory structure. This paper proposed a new method of designing a global controller for decentralized systems of a large Petri net model for flexible manufacturing systems. The proposed method can both reduce the computational complexity by decomposition of large Petri net models into several subnets and structural complexity by designing a global supervisory structure that can greatly reduce the cost at the implementation stage. Two efficient algorithms are developed in the proposed method. Algorithm 1 is used to compute decentralized working zones from the given Petri net model for flexible manufacturing systems. Algorithm 2 is used to compute the global controller that enforces the liveness to the decentralized working zones. The ring assembling method is used to reconnect and controlled the working zones via a global controller. The proposed method can be applied to large Petri nets size and, in general, it has less computational and structural complexity. Experimental examples are presented to explore the applicability of the proposed method.

Challenges in Application of Petri Nets in Manufacturing Systems

“…Flexible manufacturing systems that adapt to facts and situations in order to remain competitive in the market [35] are also widely supported by PN formalism. Even large Petri nets can be efficiently used when they are decomposed into smaller subnets [36]. Practical implementation of a set of PN controllers based on PLCs within a reasonable time is shown in [37].…”

Control and Optimization of Multi-Agent Systems and Complex Networks for Systems Engineering

“…The rest of the papers of this Special Issue can be classified into three key areas: (i) infrastructure management [3,4]; (ii) manufacturing and industrial processes [5][6][7][8]; and (iii) energy production processes [9][10][11].…”

“…Bashir et al's [7] work focused on Petri net models for a global supervisory structure design, aiming to reduce the costs and complexities of manufacturing processes. This paper proposes two algorithms.…”

An Improved Synthesis Method Based on ILPP and Colored Petri Net for Liveness Enforcing Controller of Flexible Manufacturing Systems

“…Petri nets (PNs) are efficient mathematical and graphical modeling, analysis, and control tools for FMS deadlocks [2,12,13]. It is used to depict the FMSs's properties and behaviors, including conflict, sequencing, and synchronization.…”