Fuzzy diagnosis based on P-time Petri nets for a winding machine

The fuzzy sets are applicable to many fields in which uncertainty plays a key role. Typically, manufacturing workshops with time constraints present uncertainties associated to operations. In such system, for each operation, a time interval is associated, which lower limit indicates the minimum time necessary to execute the operation. The upper limit sets the maximum time not to exceed and above which the quality of the product is deteriorated. Developments presented in this paper are devoted to the diagnosis of manufacturing job-shops with time constraints. A new method for monitoring combining P-time Petri Nets and fuzzy fault tree analysis is proposed. The purpose of the proposed approach is to explain in details what is happening on the system when time constraints are violated and to help operators identifying failures in order to avoid a damage of the process or an accident with human beings. Finally an application of the proposed approach to coil winding machine is outlined.