Derivation of placement transitions for offline calculation of restart states

This paper presents a preprocess to an existing method for offline calculation of restart states for manufacturing systems modeled by operations. In the existing method, placement transitions are used to model restart in restart states from potential error states, and supervisory control theory is used to calculate which of these transitions are valid. With the proposed preprocess, the precedence and the alternative dependencies between the operations are exploited in order to reduce the number of such placement transitions which are required in the model used by the existing method. With such a reduced model, the valid restart states for larger and more complex systems can be calculated.