Petri Networks for Mechanized Longwall System Simulation

Abstract

Modern longwall system is a complex electromechanical plant. It consists of many devices that operate together sequentially or in parallel. Petri net – consisting of places and transitions can be used as a convenient modeling language for the description of distributed and concurrent systems. The paper presents subnetwork models of the main longwall system component as shearer movement and powered roof support movement. Petri net offers a graphical notation for these discrete and time-dependent processes. One of the main advantages of the Petri networks is their similarity to the SFC language (GRAFCET) defined in the IEC 61131-3 standard, which facilitates the synthesis of discrete control algorithms implemented with PLCs. Models in the form of the timed Petri network can (with the use of appropriate simulation software) assess the performance of the modelled longwall complex, search for ways to increase this performance, and help with the verification of correct operation of control systems.