CONFUSION DIAGNOSIS AND CONTROL OF DISCRETE EVENT SYSTEMS USING SYNCHRONIZED PETRI NETS

摘要

The mixture of conflicting transitions and concurrent transitions in Petri nets can lead to the loss of conflict information, which is an unfortunate phenomenon in discrete event systems, usually called confusions. They appear in the processes of resource allocation and may cause incomplete decision-making on conflicts. Hence, a confusion detection method and a control strategy are required. This paper proposes a class of confusion control event reconfigurable (CCR) nets to control confusions with the evolution of markings. Their properties such as safety and liveness with the mapping from original Petri nets to CCR nets are investigated. Two confusion control algorithms are proposed to generate a set of control code sequences, which can completely control the occurrences of confusions. Then, a confusion detection algorithm with polynomial time complexity is developed. Finally, an example of confusion analysis in automated manufacturing systems is presented.