TY - JOUR
T1 - Liveness enforcing supervisory policies tolerant to controllability failures for discrete-event systems modeled by Petri Nets
AU - Raman, Arun
AU - Sreenivas, Ramavarapu S.
N1 - Funding Information:
This work was supported in part by the Office of Naval Research, United States of America under Grant N00014-20-1-2249 . The material in this paper was not presented at any conference. This paper was recommended for publication in revised form by Associate Editor Christoforos Hadjicostis under the direction of Editor Christos G. Cassandras.
Publisher Copyright:
© 2021 Elsevier Ltd
PY - 2021/3
Y1 - 2021/3
N2 - A Discrete Event System (DES) modeled by a Petri Net (PN) is live if it is possible to fire any transition, although not necessarily immediately, from any marking that is reachable from the initial marking. A Liveness Enforcing Supervisory Policy (LESP) for a PN enforces liveness by preventing the firing of a subset of transitions called the controllable transitions, which correspond to the preventable events in a DES. In this paper, we consider the existence and synthesis of LESPs for arbitrary PNs in the presence of faults, where a subset of controllable transitions become temporarily uncontrollable, for a finite number of event occurrences. Following the formal specification of the fault model, we present a necessary and sufficient condition for the existence of Fault-Tolerant LESPs (FT-LESPs) for arbitrary PNs. We show that, even when an LESP is given, the existence of an FT-LESP for an arbitrary PN is undecidable. We then identify a class of PNs for which the existence of FT-LESPs is decidable. We conclude with some suggestions for future research.
AB - A Discrete Event System (DES) modeled by a Petri Net (PN) is live if it is possible to fire any transition, although not necessarily immediately, from any marking that is reachable from the initial marking. A Liveness Enforcing Supervisory Policy (LESP) for a PN enforces liveness by preventing the firing of a subset of transitions called the controllable transitions, which correspond to the preventable events in a DES. In this paper, we consider the existence and synthesis of LESPs for arbitrary PNs in the presence of faults, where a subset of controllable transitions become temporarily uncontrollable, for a finite number of event occurrences. Following the formal specification of the fault model, we present a necessary and sufficient condition for the existence of Fault-Tolerant LESPs (FT-LESPs) for arbitrary PNs. We show that, even when an LESP is given, the existence of an FT-LESP for an arbitrary PN is undecidable. We then identify a class of PNs for which the existence of FT-LESPs is decidable. We conclude with some suggestions for future research.
KW - Deadlock
KW - Discrete-event dynamic systems
KW - Discrete-event systems
KW - Fault-tolerant systems
KW - Petri-Nets
KW - Supervisory control
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U2 - 10.1016/j.automatica.2020.109430
DO - 10.1016/j.automatica.2020.109430
M3 - Article
AN - SCOPUS:85099179998
SN - 0005-1098
VL - 125
JO - Automatica
JF - Automatica
M1 - 109430
ER -