1 / 2017-02-21 14:10:53

A Control Algorithm Using a Revised MIP Method to Deal With Livelocks in S4R of Petri Nets

12904,12905,12906,12907,12908

A Control Algorithm Using a Revised MIP Method to Deal With Livelocks in S4R of Petri Nets
Shaoyong Li, C. Hailin Li, Xianhong Wei, Zongli Wu, Ying Cai, Xilian Han

School of Civil Engineering, Lanzhou University of Technology, Lanzhou 730050
E-mail: lishaoyong99@163.com


Abstract: Livelocks, like deadlocks, can result in the serious results in running process of flexible manufacturing systems (FMSs) as well. Current deadlock control policies (DCP) based on mixed integer programming (MIP) cannot detect siphons that cause and cope with livelocks in Petri nets. This study proposes a revised MIP method to directly solve the new smart siphons (NSSs) associated with livelocks or deadlocks in a system of sequential systems with shared resources (S4R), a typical subclass of generalized Petri net models. Accordingly, the solved NSSs are max’-controlled by adding the corresponding control places (CPs). As a result, an original S4R system with livelocks or deadlocks can be converted into the live controlled Petri net system. The related theoretical analysis and an example are given to demonstrate the proposed RMIP and the corresponding control algorithm (CA).
Key Words: flexible manufacturing system (FMS), Petri nets, livelocks, revised mixed integer programming (RMIP), live controlled Petri net system