A Novel and Advantageous Recovery Solution for Deadlock Problem of Flexible Manufacturing Systems Based on Petri Nets Modeling Theory

Instead of the mass production industry in the past, over these decades, precision and automatic manufacturing have become more and more widely accepted in the production area. With highly variable productivity and flexibility, Flexible Manufacturing Systems (FMS) can decrease production costs and increase efficiency. Due to its resource sharing, unexpected system deadlock may occur in some situations. In research on system deadlock control, lots of existing literature use deadlock prevention as the primary control method, while it could block resources transporting and downscale the system reachability graph. This paper adopts a deadlock recovery policy as the direct control strategy based on control transition technology. This kind of control strategy and its benefit could be demonstrated through classical systems of simple sequential processes with resources (S³PR) nets and their Petri nets model.

Introduction

As a well-known mathematical modeling language, Petri Nets (PNs) [1–3] is a class of Discrete Event Dynamic Systems (DEDS). It is also widely applied to present and analyze most of the distributed systems [4–5]. Carl A. Petri firstly developed PN in 1962 [1–2], whom the theory of PN is named after. In this paper, we use PNs to simulate FMS and design a high-efficiency solution of system deadlocks. We also adopt Reachability Graph (RG) analysis to help finding out all reachable markings in FMS.