Abstract: Considering the characteristics of virtual enterprises task scheduling, timed place Petri-net(TPPN) based approach is proposed to model the task scheduling. On the basis of formal definition and transition rules of the TPPN, product manufacturing types in virtual enterprises are classified, and the TPPN model of each kind of manufacturing is provided, then the methods of resolving critical path with place zero activity floats and solving reasonable scheduling scheme with reachability graph are analyzed. Finally, the simulation of a case indicates that the approach is feasible and effective.

Key words: task scheduling, timed palce Petri-net, virtual enterprises