An Approximation Method For The Performance Analysis Of Manufacturing Systems Based On GSPNs

The response time approximation (RTA) technique for the performance analysis of generalized stochastic Petri net s y s t e r n is based on single or multiple cuts and has previously been introduced in the context of Marked Graphs. In this paper, Macroplace-Macrotransition-nets (MPMT-nets) are introduced, a subclass of Petri nets that allows limited choice, concurrency and sharing of resources. RTA has been extended to include MPMT-nets and can therefore be seen as a relatively general approximation technique. The accuracy of RTA is tested by analyzing various flow lines using single cuts and a hierarchical decomposition scheme. The results are compared to the approximation method of Choong, which is specifically designed for flow lines with unreliable machines. The comparison shows that,-in general, the special purpose method is superior to RTA, but RTA can model a larger variety of systems than just flow lines. Nevertheless it is possible to give guidelines for single cuts that will result in a low error (less than 8%).