PNETLAB: A TOOL FOR THE SIMULATION, ANALYSIS AND CONTROL OF DISCRETE EVENT SYSTEMS BASED ON PETRI NETS

摘要

Although supervisory control based on Petri Nets (PNs) appeared in literature in the early 90's, nowadays there is no tool which allows the analysis and simulation of the plant (modelled as a PN) together with the controller/supervisor that can be a PN itself (compiled supervisor case) or a program (interpreted supervisor case). A lot of commercial or freeware tools have been developed with the aim of analyzing and simulating a PN model, in timed or untimed case, and Colored Timed Petri Nets (CTPNs). In this paper we present PNetLab, a freeware tool developed by the Automatic Control Group of the University of Salerno. It allows the drawing of a PN model by a Java graphical user interface. The definition of a controller as a PN (CTPN) or as a standard C/C++ program is also possible. The simulation of the closed loop system and the token game in the timed and untimed case are performed. In addition, for the open loop PN model, the tool performs P-invariant, T-invariant, minimal siphon and trap computation. PNetLab can compute the coverability tree both for the open loop and closed loop system, and it offers a very suitable management of the transition conflicts. The tool functionality are shown via two detailed examples.