Specification method based on temporal SADT and deterministic/stochastic Petri nets. Application to safety assessment

A significant complexity of automated manufacturing systems (AMS) requires methods and tools which must allow preliminary safety analysis beginning right from the start of the design cycle. In this paper we propose a new specification method for AMS, based on temporal SADT and deterministic/stochastic Petri nets (DSPN). Temporal SADT complements conventional SADT with temporal description and additional operators leading to both dynamic and simulation SADT diagrams. Creating his own temporal SADT specification, the user can simultaneously develops its Petri net representation. At this level of specification the required calculations can be undertaken due to the mathematical PN formalism and the possibility of transforming the DSPN into a Markov graph. Such calculations allow us to detect errors and to estimate a system safety at the start of the design. Because of its structured and hierarchical formalism, the proposed method contributes to facilitating the communication between different members of the project team.