n this paper, the forbidden state problem, in the context of supervisory control of discrete event systems modelled by Petri nets, is discussed. The forbidden state problem is specified by generalized mutual exclusion constraints (GMECs). The case of backward conflict free and free choice uncontrollable subnet is considered. The uncontrollable subnet is first extended to a number of well formed free choice nets and then decomposed in marked graph components, which can be obtained from minimal T-invariants of the extended net. The forbidden state problem is so re-formulated into an equivalent one, based on the decomposed net, such that it can be solved by a linear programming problem. Thus, a polynomial complexity solution, suitable for on-line control, is achieved, improving the existing results in literature for this net subclass.
Feedback control logic for backward conflict free choice nets
BASILE, FRANCESCO;CARBONE, CIRO;CHIACCHIO, Pasquale
2005-01-01
Abstract
n this paper, the forbidden state problem, in the context of supervisory control of discrete event systems modelled by Petri nets, is discussed. The forbidden state problem is specified by generalized mutual exclusion constraints (GMECs). The case of backward conflict free and free choice uncontrollable subnet is considered. The uncontrollable subnet is first extended to a number of well formed free choice nets and then decomposed in marked graph components, which can be obtained from minimal T-invariants of the extended net. The forbidden state problem is so re-formulated into an equivalent one, based on the decomposed net, such that it can be solved by a linear programming problem. Thus, a polynomial complexity solution, suitable for on-line control, is achieved, improving the existing results in literature for this net subclass.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
