Monitoring manufacturing systems by means of Petri nets with imprecise markings

An attempt is made to introduce imprecision and uncertainty within Petri net theory in order to take into account abnormal events as well as the normal operation for the control and monitoring of flexible manufacturing systems. The uncertainty and imprecision concepts are introduced through a modification of the marking of a Petri net with objects and through time handling. The approach is based on the association of fuzzy enabling duration with the transition which results in attaching a fuzzy firing date to the transition. Some examples of possible use are presented