An integrated control method for designing non-blocking supervisors using Petri nets

Abstract

This article presents an efficient integrated approach on designing a non-blocking supervisor for the most general classes of Petri nets, called G-systems that allow multiple resource acquisitions. This work mainly focuses on developing a deadlock prevention policy with a polynomial computational complexity. First, an extraction algorithm of liveness requirement constraints is presented according to the concept of resource partial orders. By considering the different resource requirements of various processes, monitors are added for the uncontrolled G-system on the basis of those precise linear inequality constraints. Afterward, we explore an iterative control policy by utilizing the traditional mathematical programming method, which can ensure the liveness of the resultant controlled system. Comparing with the existing deadlock control policies reported in the literature, the proposed method can achieve a non-blocking controlled G-system with simple structure and high computational efficiency. Finally, a benchmark G-system example is used to substantiate the efficiency of the new method.

Colored Resource-Oriented Petri Net Based Ladder Diagrams for PLC Implementation in Reconfigurable Manufacturing Systems

“…The everincreasing complexity of the PLC software and user-imposed operational and security specifications require new techniques to meet the control requirements. Petri nets (PNs) are a very interesting and useful graphical and mathematical tool for the modeling and control of manufacturing systems [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. Indeed, PNs have advantages over other languages, including simple graphical representation (circles, rectangles, and arcs), structured algorithms, and simple algebraic representation [18,19].…”

Liveness characteristic analysis of a class of Petri nets

“…Consequently, many investigations focus on deadlock control in FMSs. [1][2][3][4][5] Due to their appealing formal and graphical representation, Petri nets (PNs) are extensively adopted for modeling, analysis, scheduling, [6][7][8][9] and supervisory control [10][11][12] and hence adopted for handling the deadlock problems in FMSs. A seminal work in Zhou and Dicesare 13 contributes a PN model synthesis method for FMSs, where the places in a PN that are modeling of an FMS are first classified to A-, B-, and C-places.…”

“…Nevertheless, the approaches in Chen et al 24 cannot deal with a large-scale systems with a large initial marking due to the state explosion problem. 25 The works in Zhao 4 provide a deadlock control policy based on the divide-and-conquer strategy. However, the method in Zhao 4 has a high computational complexity since it needs to handle a large number of subsystems.…”

“…25 The works in Zhao 4 provide a deadlock control policy based on the divide-and-conquer strategy. However, the method in Zhao 4 has a high computational complexity since it needs to handle a large number of subsystems.…”

Modeling, scheduling, and control in advanced production systems

“…The proposed strategy can also improve the utilization rate of the available loads. The third article, authored by Zhao, 11 aims to design a supervisor for a production system where an operation may have multiple resource acquisition requirements such that the system is blocking-free. A two-stage method is proposed to synthesize a blocking-free supervisor and it is shown that such a supervisor with simple controller structure can be efficiently designed.…”