A Constraint Transformation Technique for Petri Nets with Certain Uncontrollable Structures

In this paper we study the problem of constraint transformation. We consider a special type of system in which the uncontrollable subnet is an assembly flow system, which is a subclass of backward-synchronization-backward-conflict-free Petri net. We propose an algorithm to transform a given inadmissable GMEC into an equivalent admissible OR-GMEC. The algorithm is based on a technique that adds new constraints obtained by composition of elementary ones.