Modeling andControl ofFlowshopProduction Systems byFuzzyMax-Plus Algebra

Flowshopproduction lines areverycommonin manufacturing systems suchascarassemblies, manufacturing ofelectronic circuits, etc. Inthis paper, Tomodeltheuncertainty embedded inservice times, allservice times arefirst considered intheformoffuzzy numbers. Also, asystematic procedure is givenforgenerating event-timing equations directly fromthe machineinterconnections fora generalized flowshopsystem. Then,anadaptive fuzzycontroller isproposed toadjust the numberofparts percycle entering thesystem. Bythedefinition ofa newmeasureforaproduction systemtheproposed fuzzy controller isimplemented using onlythetimedifference between outputs departure times andinput release times. Thisapproach isalsorobust toservice timevariations, andalsotothesystem emergency conditions. I.INTRODUCTION Recently, application ofdiscrete eventsystems inthe modeling ofproduction systems hasattracted agreat atten- tionofmanyresearchers. Ingeneral, modeling ofproduction systems canbeclassified astwodifferent categories, onethat deals withthelogical aspects oftheproduction systems andthe other that deals withthequantitative aspects ofsuchsystems.