A NEW RELEASE OF MODIFIED DISSIMILARITY MAXIMIZATION METHOD FOR REAL TIME ALTERNATIVE ROUTING SELECTION IN AN FMS

Abstract

Routing flexibility is one of among common types of flexibilities that exist in flexible manufacturing systems. It can be found in each system that contains alternative, identical machines or redundant machine tools. Modified DMM (Dissimilarity Maximization Method) is one of the most recent proposed heuristics for real time FMS scheduling by considering the routing flexibility. This rule is developed for part routing decisions by using a dissimilarity coefficient used to differ the routings from others in terms of the machines types, in order to reduce the congestion in the system and consequently improving the system throughput. This work presents an improvement of this method with a new dissimilarity coefficient which takes into account the breakdowns probability in the procedure of selecting a routing for a part. The simulation experimentation results obtained with presence of breakdowns after several simulations in a typical flexible manufacturing show that for an overloaded system, the new approach improve clearly the system performances in terms the production rate, machines and material handling utilisation rate.